Monday, December 29, 2008

Iodine benefits

Iodine is a component of the thyroid hormones thyroxine and triiodothyronine, which help regulate cell activities. These hormones are also essential for protein synthesis, tissue growth (including the formation of healthy nerves and bones), and reproduction.
The best natural sources of iodine are seafood and plants grown near the ocean, but modern Americans are most likely to get the iodine they need from iodized salt (plain table salt with iodine added). And here’s an odd nutritional note: You may get substantial amounts of iodine from milk. Are the cows consuming iodized salt? No. The milk is processed and stored in machines and vessels kept clean and sanitary with iodates and iodophors, iodine-based disinfectants. Tiny trace amounts get into the products sent to the stores. Iodates are also used as dough conditioners (additives that make dough more pliable), so you’re also likely to find some iodine in most bread sold in supermarkets.

Zinc benefits

Zinc protects nerve and brain tissue, bolsters the immune system, and is essential for healthy growth. Zinc is part of the enzymes (and hormones such as insulin) that metabolize food, and you can fairly call it the macho male mineral.
The largest quantities of zinc in the male human body are in the testes, where it’s used in making a continuous supply of testosterone, the hormone a man needs to produce plentiful amounts of healthy, viable sperm. Without enough zinc, male fertility falters. So, yes, the old wives’ tale is true: Oysters — a rich source of zinc — are useful for men. By the way, women also need zinc . . . just not as much as men do.
Other good sources of zinc are meat, liver, and eggs. Plenty of zinc is in nuts, beans, miso, pumpkin and sunflower seeds, whole-grain products, and wheat germ. But the zinc in plants, like the iron in plants, occurs in compounds that your body absorbs less efficiently than the zinc in foods from animals.

Iron benefits

Iron is an essential constituent of hemoglobin and myoglobin, two proteins that store and transport oxygen. You find hemoglobin in red blood cells (it’s what makes them red). Myoglobin (myo = muscle) is in muscle tissue. Iron also is part of various enzymes.
Your best food sources of iron are organ meats (liver, heart, kidneys), red meat, egg yolks, wheat germ, and oysters. These foods contain heme (heme = blood) iron, a form of iron that your body can easily absorb. Whole grains, wheat germ, raisins, nuts, seed, prunes and prune juice, and potato skins contain nonheme iron. Because plants contain substances called phytates, which bind this iron into compounds, your body has a hard time getting at the iron. Eating plant foods with meat or with foods that are rich in vitamin C (like tomatoes) increases your ability to split away the phytates and get iron out of plant foods.

Magnesium benefits

Your body uses magnesium to make body tissues, especially bone. The adult human body has about an ounce of magnesium, and three-quarters of it is in the bones. Magnesium also is part of more than 300 different enzymes that trigger chemical reactions throughout your body. You use magnesium to
  • Move nutrients in and out of cells
  • Send messages between cells
  • Transmit the genetic code (genes and chromosomes) when cells divide and reproduce
An adequate supply of magnesium also is heart-healthy because it enables you to convert food to energy using less oxygen. Bananas are a good source of magnesium and so are many other plant foods, including dark green fruits and vegetables (magnesium is part of chlorophyll, the green pigment in plants), whole seeds, nuts, beans, and grains.

Phosphorus Benefits

Like calcium, phosphorus is essential for strong bones and teeth. For tiptop performance, you need about half as much phosphorus as calcium. Phosphorus also enables a cell to transmit the genetic code (genes and chromosomes that carry information about your special characteristics) to the new cells created when a cell divides and reproduces. In addition, phosphorus
  • Helps maintain the pH balance of blood (that is, keeps it from being too acidic or too alkaline)
  • Is vital for metabolizing carbohydrates, synthesizing proteins, and ferrying fats and fatty acids among tissues and organs
  • Is part of myelin, the fatty sheath that surrounds and protects each nerve cell Phosphorus is in almost everything you eat, but the best sources are highprotein foods such as meat, fish, poultry, eggs, and milk. These foods provide more than half the phosphorus in a nonvegetarian diet; grains, nuts, seeds, and dry beans also provide respectable amounts.

Sunday, December 14, 2008

Calcium: The bone team player

The toe bone’s connected to the foot bone. The foot bone’s connected to the anklebone. The anklebone’s connected to the knee bone. And what holds them together all the way up to the head bone is connected to your diet. Like all body tissues, bones are constantly being replenished. Old bone cells break down, and new ones are born. Specialized cells called osteoclasts start the process by boring tiny holes into solid bone so that other specialized cells, called osteoblasts, can refill the open spaces with fresh bone. At that point, crystals of calcium, the best-known dietary bone builder, glom onto the network of new bone cells to harden and strengthen the bone.
Calcium begins its work on your bones while you’re still in your mother’s womb. But it’s not the only mineral at play. You should also think zinc. Based on a survey of 242 pregnant women in Peru, where zinc deficiency is common, Johns Hopkins researchers found the babies born to women who got prenatal supplements with iron, folic acid, and zinc had longer, stronger legs bones than did babies born to women who got the same supplement minus the zinc. After you’re born, calcium continues to build your bones, but only with the help of vitamin D, which produces a calcium-binding protein that enables you to absorb the calcium in the milk Mummy feeds you. To make sure you get your D, virtually all milk sold in the United States is fortified with the vitamin. And because you may outgrow your taste for milk but never outgrow your need for calcium, calcium supplements for adults frequently include vitamin D. But vitamin D isn’t milk’s only contribution. Remember the iron in the Peruvian (and American) prenatal supplements? It isn’t there by accident. Iron increases the production of collagen, the most important protein in bone. Milk contains lactoferrin (lacto = milk; ferri = iron), an iron-binding compound that stimulates the production of the cells that promote bone growth. When researchers at the University of Auckland in New Zealand added lactoferrin from cow’s milk to a dish of osteoblasts, the bone cells grew more quickly. When they injected lactoferrin into the skulls of five lab mice, the bone at the site of the injection also grew faster, leading the team to suggest in the journal Endocrinology that lactoferrin may play a role in treating osteoporosis. No surprise to the Department of Nutrition Sciences at the University of Arizona, where a study done with scientists from the University of Arkansas and Columbia University shows that women in their 40s, 50s, and 60s who get about 18 milligrams of iron a day have stronger, denser bones than women who get less iron. What makes this intriguing is that 18 milligrams a day is more than double the current RDA (8 milligrams) for older women.
But the iron/calcium dance is a balancing act. In your body, iron and calcium appear to compete to see which one gets absorbed. So the extra iron works only for women who get about 800 to 1,200 milligrams calcium a day — women who get less and women who get more don’t seem to benefit from extra iron.
Finally, please note that the word bones begins with b — as in vitamin B12. The female sex hormone estrogen preserves bone; the male sex hormone testosterone builds new bone. As people age and their supply of sex hormones diminishes, they lose bone faster than they can levels of vitamin B12. A report in the Journal of Clinical Endocrinology and Metabolism says that researchers at the University of California, San Francisco, found that women with lower levels of this vitamin also have less dense hip bones. So to protect your bones, you need calcium, zinc, iron, and vitamins D and B12, all found most abundantly in milk, cheese, eggs, and red meat. Which sounds like a cardiologist’s nutritional high-fat, high-cholesterol nightmare — unless you edit the menu to read: skim milk, low-fat cheese, egg whites, and lean beef. Way to go.

Calcium Benefits

When you step on the scale in the morning, you can assume that about three pounds of your body weight is calcium, most of it packed into your bones and teeth.
Calcium is also present in extracellular fluid (the liquid around body cells), where it performs the following duties:
  • Regulating fluid balance by controlling the flow of water in and out of cells
  • Enabling cells to send messages back and forth from one to another
  • Keeping muscles moving smoothly and preventing cramping
An adequate amount of calcium is important for controlling high blood pressure — and not only for the person who takes the calcium directly. At least one study shows that when a pregnant woman gets a sufficient amount of calcium, her baby’s blood pressure stays lower than average for at least the first seven years of life, meaning a lower risk of developing high blood pressure later on. Your best food sources of calcium are milk and dairy products, plus fish such as canned sardines and salmon. Calcium also is found in dark green leafy vegetables, but the calcium in plant foods is bound into compounds that are less easily absorbed by your body.

An elementary guide to minerals

The early Greeks thought that all material on Earth was constructed of a combination of four basic elements: earth, water, air, and fire. Wrong. Centuries later, alchemists looking for the formula for precious metals, such as gold, decided that the essential elements were sulfur, salt, and mercury. Wrong again.
In 1669, a group of German chemists isolated phosphorus, the first mineral element to be accurately identified. After that, things moved a bit more swiftly. By the end of the 19th century, scientists knew the names and chemical properties of 82 elements. Today, 112 elements have been identified.
The classic guide to chemical elements is the periodic table, a chart devised in 1869 by Russian chemist Dmitri Mendeleev (1834–1907), for whom mendelevium was named. The table was revised by British physicist Henry Moseley (1887–1915), who came up with the concept of atomic numbers, numbers based on the number of protons (positively charged particles) in an elemental atom.
The periodic table is a clean, crisp way of characterizing the elements, and if you are now or ever were a chemistry, physics, or premed student, you can testify firsthand to the joy (maybe that’s not the best word?) of memorizing the information it provides. Personally, I’d rather be forced to watch reruns of The Dating Game.

Introducing the major minerals

The following major minerals are essential for human beings:
_ Calcium
_ Phosphorus
_ Magnesium
_ Sulfur
_ Sodium
_ Potassium
_ Chloride
Note: Sodium, potassium, and chloride, also known as the principal electrolytes.
Although sulfur, a major mineral, is an essential nutrient for human beings, it’s almost never included in nutritional books and/or charts. Why? Because it’s an integral part of all proteins. Any diet that provides adequate protein also provides adequate sulfur.
After you’ve checked out proteins, come on back to look at the major minerals in minute detail.

Mineral Benefits

Think of your body as a house. Vitamins are like tiny little maids and butlers, scurrying about to turn on the lights and make sure that the windows are closed to keep the heat from escaping. Minerals are more sturdy stuff, the mortar and bricks that strengthen the frame of the house and the current that keeps the lights running. Nutritionists classify the minerals essential for human life as either major minerals (including the principal electrolytes) or trace elements. Major minerals and trace elements are both minerals. The difference between them, nutritionally speaking, is how much you have in your body and how much you need to take in to maintain a steady supply. Your body stores varying amounts of minerals but keeps more than 5 grams (about 1⁄6 of an ounce) of each of the major minerals and principal electrolytes on hand; you need to consume more than 100 milligrams a day of each major mineral to maintain a steady supply and to make up for losses. You store less than 5 grams of each trace element and need to take in less than 100 milligrams a day to stay even.
Some minerals interact with other minerals or with medical drugs. For example, calcium binds tetracycline antibiotics into compounds your body can’t break apart so that the antibiotic moves out of your digestive tract, unabsorbed and unused. That’s why your doctor warns you off milk and dairy products when you’re taking this medicine.

Saturday, November 29, 2008

Taking extra vitamin during pregnancy

Keep in mind that “eating for two” means that you’re the sole source of nutrients for the growing fetus, not that you need to double the amount of food you eat. If you don’t get the vitamins you need, neither will your baby. The RDAs for many nutrients are the same as those for women who aren’t pregnant. But when you’re pregnant, you need extra
  • Vitamin D: Every smidgen of vitamin D in a newborn’s body came from his or her mom. If the mother doesn’t have enough D, neither will the baby. Are vitamin pills the answer? Yes. And no. The qualifier is how many pills, because although too little vitamin D can weaken a developing fetus, too much can cause birth defects. That’s why until new recommendations for vitamin D are issued, the second important d-word is “doctor.” As in, check with yours to see what’s right for you.
  • Vitamin E: To create all that new tissue (the woman’s as well as the baby’s), a pregnant woman needs an extra 2 a-TE each day, the approximate amount in one egg.
  • Vitamin C: The level of vitamin C in your blood falls as your vitamin C flows across the placenta to your baby, who may — at some point in the pregnancy — have vitamin C levels as much as 50 percent higher than yours. So you need an extra 10 milligrams vitamin C each day (1⁄2 cup cooked zucchini or 2 stalks of asparagus).
  • Riboflavin (vitamin B2): To protect the baby against structural defects such as cleft palate or a deformed heart, a pregnant woman needs an extra 0.3 milligrams riboflavin each day (slightly less than 1 ounce of ready-to-eat cereal).
  • Folate: Folate protects the child against cleft palate and neural tube (spinal cord) defects. As many as two of every 1,000 babies born each year in the United States have a neural tube defect such as spina bifida because their mothers didn’t get enough folate to meet the RDA standard. The accepted increase in folate for pregnant women has been 200 micrograms (slightly more than the amount in 8 ounces of orange juice). But new studies show that taking 400 micrograms folate before becoming pregnant and through the first two months of pregnancy significantly lowers the risk of giving birth to a child with cleft palate. Taking 400 micrograms folate each day through an entire pregnancy reduces the risk of neural tube defect.
  • Vitamin B12: To meet the demands of the growing fetus, a pregnant woman needs an extra 0.2 micrograms vitamin B12 each day (just 3 ounces of roast chicken).

Taking Extra Vitamins as Needed

Who needs extra vitamins? Maybe you. The RDAs are designed to protect healthy people from deficiencies, but sometimes the circumstances of your life (or your lifestyle) mean that you need something extra. Are you taking medication? Do you smoke? Are you on a restricted diet? Are you pregnant? Are you a nursing mother? Are you approaching menopause? Answer “yes” to any of these questions, and you may be a person who needs larger amounts of vitamins than the RDAs provide.

I’m taking medication
Many valuable medicines interact with vitamins. Some drugs increase or decrease the effectiveness of vitamins; some vitamins increase or decrease the effectiveness of drugs. For example, a woman who’s using birth control pills may absorb less than the customary amount of the B vitamins. For more about vitamin and drug interactions.

I’m a smoker
It’s a fact — you probably have abnormally low blood levels of vitamin C. More trouble: Chemicals from tobacco smoke create more free radicals in your body. Even the National Research Council, which is tough on vitamin overdosing, says that regular smokers need to take about 66 percent more vitamin C — up to 100 mg a day — than nonsmokers.

I never eat animals
On the other hand, if you’re nuts for veggies but follow a vegan diet — one that shuns all foods from animals (including milk, cheese, eggs, and fish oils) — you simply cannot get enough vitamin D without taking supplements. Vegans also benefit from extra vitamin C because it increases their ability to absorb iron from plant food. And vitamin B12–enriched grains or supplements are a must to supply the nutrient found only in fish, poultry, milk, cheese, and eggs.

I’m a couch potato who plans to start working out
When you do head for the gym, take it slow, and take an extra dose of vitamin E. A study at the USDA Center for Human Nutrition at Tufts University (Boston) suggests that an 800 milligram vitamin E supplement every day for the first month after you begin exercising minimizes muscle damage by preventing reactions with free radicals (parts of molecules) that cause inflammation. After that, you’re on your own: The vitamin doesn’t help conditioned athletes whose muscles have adapted to workout stress.

I’m breast-feeding
You need extra vitamin A, vitamin E, thiamin, riboflavin, and folate to produce sufficient quantities of nutritious breast milk, about 750 milliters (3⁄4 liter) each day. You need extra vitamin D, vitamin C, and niacin as insurance to replace the vitamins you lose — that is, the ones you transfer to your child in your milk.

I’m approaching menopause
Information about the specific vitamin requirements of older women is as hard to find as, well, information about the specific vitamin requirements about older men. It’s enough to make you wonder what’s going on with the people who set the RDAs. Don’t they know that everyone gets older? Right now, just about all anybody can say for sure about the nutritional needs of older women is that they require extra calcium to stem the natural loss of bone that occurs when women reach menopause and their production of the female hormone estrogen declines. They may also need extra vitamin D to enable their bodies to absorb and use the calcium. Gender Bias Alert! No similar studies are available for older men. But adding vitamin D supplements to calcium supplements increases bone density in older people. The current RDA for vitamin D is set at 5 micrograms/200 IU for all adults, but the new AI (Adequate Intake) for vitamin D is 10 micrograms/400 IU for people ages 51 to 70 and 15 micrograms/600 IU or more for people 71 and older. Some researchers suggest that even these amounts may be too low to guarantee maximum calcium absorption.
Check with your doctor before adding vitamin D supplements. In very large amounts, this vitamin can be toxic.

I have very light skin or very dark skin
Sunlight — yes, plain old sunlight — transforms fats just under the surface of your skin to vitamin D. So getting what you need should be a cinch, right? Not necessarily. Getting enough vitamin D from sunlight is hard to do when you have very light skin and avoid the sun for fear of skin cancer. Even more difficult is getting enough vitamin D when you have very dark skin, which acts as a kind of natural sunblock. When Centers for Disease Control and Prevention researchers surveyed the vitamin D status of more than 2,000 African American and Caucasian women ages 15 to 49, they found low body levels of vitamin D in 42 percent of the African American women and 4.2 percent of the Caucasian women. Based on these numbers, Boston University researchers suggest that the Recommended Dietary Amount for adults who don’t get enough sunlight may be as much as four times the current recommended amount. Check this out with your doctor; it’s very important news for women who are or hope to be pregnant and need extra vitamin D (check back a few paragraphs for this information).

A special case: The continuing saga of vitamin C

In 1970, chemist Linus Pauling published Vitamin C and the Common Cold, a small book (just about 100 pages) made weightier by the fact that Pauling had not one, but two Nobel prizes on his shelf — one for chemistry and one for peace. Ever since, people have been fighting over Pauling’s message that very large doses of vitamin C — called gram doses because they provide more than 1,000 milligrams (1 gram) — prevent or cure the common cold or his later (unfounded) claim that these doses may also cure advanced cancer.
Over the past decade, the argument has switched to vitamin C’s reputed ability to protect heart health. For example, an April 2004 report in the Journal of the American College of Nutrition said vitamin C could lower blood levels of CRP, an inflammation-related protein that increases the risk of heart disease. University of California, Berkeley, researchers gave 160 healthy adult volunteers either 500 milligrams vitamin C or a mixture of antioxidant nutrients or a look-alike pill with no nutrients once a day for two months. In the end, the folks who got the vitamin C experienced a 24 percent drop in CRP blood levels versus a statistically insignificant 4.7 percent for the cocktail and no change at all for those on the placebo. Not surprisingly, UC epidemiologists thought vitamin C may become an important aid to heart health.
Unless, that is, you’re taking medicines to knock down your “bad” cholesterol and boost the “good” kind. As the American Heart Association (AHA) Council on Nutrition Physical Activity and Metabolism points out, when 20 volunteers in an HDL-Atherosclerosis Treatment Study were given vitamin C supplements along with their anti-cholesterol meds, they ended up with lowerthan-expected levels of heart healthy high density lipoproteins (HDLs). In another small study, women taking antioxidant vitamins along with post-menopausal estrogens were more likely than those taking look-alike pills to die from their heart disease.
Oh, well. Nothing’s perfect.

Vitamin Megadoses, Is it Dangerous?

  • Vitamin A 15,000 to 25,000 IU retinol a day for adults (2,000 IU or more for children) may lead to liver damage, headache, vomiting, abnormal vision, constipation, hair loss, loss of appetite, low-grade fever, bone pain, sleep disorders, and dry skin and mucous membranes. A pregnant woman who takes more than 10,000 IU a day doubles her risk of giving birth to a child with birth defects.
  • Vitamin D 2,000 IU a day can cause irreversible damage to kidneys and heart. Smaller doses may cause muscle weakness, headache, nausea, vomiting, high blood pressure, retarded physical growth, and mental retardation in children, and fetal abnormalities. Vitamin E Large amounts (more than 400 to 800 IU a day) may cause upset stomach or dizziness.
  • Vitamin C 1,000 mg or higher may cause upset stomach, diarrhea, or constipation.
  • Niacin Doses higher than the RDA raise the production of liver enzymes and blood levels of sugar and uric acid, leading to liver damage and an increased risk of diabetes and gout.
  • Vitamin B6 Continued use of 50 mg or more a day may damage nerves in arms, legs, hands, and feet. Some experts say the damage is likely to be temporary; others say that it may be permanent.
  • Choline Very high doses (14 to 37 times the adequate amount) have been linked to vomiting, salivation, sweating, low blood pressure, and — ugh! — fishy body odor.
You may not have to go sky-high on vitamin A to run into trouble. In January 2003, new data from a long-running (30-year) study at University Hospital in Uppsala (Sweden) suggested that taking a multivitamin with normal amounts of vitamin A may weaken bones and raise the risk of hip fractures by as much as 700 percent, a conclusion supported by data released in 2004 from the long-running Nurses’ Health Study. A high blood level of retinol — from large amounts of vitamin A from food or supplements — apparently inhibits special cells that usually make new bone, revs up cells that destroy bone, and interferes with vitamin D’s ability to help you absorb calcium. Of course, confirming studies are needed, but you can bet the debate about lowering the
amount of A in your favorite supplement will be vigorous. The new recommendations for vitamin A are 700 RE/2,300 IU of vitamin A for women and 900 RE/3,000 IU for men, but many popular multivitamins still contain 750–1500 RE/2,500–5,000 IU. Oooops?

Big trouble: Vitamin megadoses

Can you get too much of a good thing? Darn right, you can. Some vitamins are toxic when taken in the very large amounts popularly known as megadoses. How much is a megadose? Nobody knows for sure. The general consensus, however, is that a megadose is several times the RDA, but the term is so vague that it’s in neither my medical dictionary nor the dictionary on my computer.
  • Megadoses of vitamin A (as retinol) may cause symptoms that make you think you have a brain tumor. Taken by a pregnant woman, megadoses of vitamin A may damage the fetus.
  • Megadoses of vitamin D may cause kidney stones and hard lumps of calcium in soft tissue (muscles and organs).
  • Megadoses of niacin (sometimes used to lower cholesterol levels) can damage liver tissue.
  • Megadoses of vitamin B6 can cause (temporary) damage to nerves in arms and legs, fingers, and toes.
But here’s an interesting fact: With one exception, the likeliest way to get a megadose of vitamins is to take supplements. It’s pretty much impossible for you to cram down enough food to overdose on vitamins D, E, K, C, and all the Bs. Did you notice the exception? Right: vitamin A. Liver and fish liver oils are concentrated sources of preformed vitamin A (retinol), the potentially toxic form of vitamin A. Liver contains so much retinol that early 20th century explorers to the South Pole made themselves sick on seal and whale liver. Cases of vitamin A toxicity also have been reported among children given daily servings of chicken liver. On the other hand, even very large doses of vitamin E, vitamin K, thiamin (vitamin B1), riboflavin (vitamin B2), folate, vitamin B12, biotin, and pantothenic acid appear safe for human beings.

Thursday, November 13, 2008

Vitamin deficiencies

The good news is that vitamin deficiencies are rare among people who have access to a wide variety of foods and know how to put together a balanced diet. For example, the only people likely to experience a vitamin E deficiency are premature and/or low–birth weight infants and people with a metabolic disorder that keeps them from absorbing fat. A healthy adult may go as long as 10 years on a vitamin E–deficient diet without developing any signs of a problem. Aha, you say, but what’s this subclinical deficiency I hear so much about? Nutritionists use the term subclinical deficiency to describe a nutritional deficit not yet far enough advanced to produce obvious symptoms. In lay terms, however, the phrase has become a handy explanation for common but hard-to-pin-down symptoms such as fatigue, irritability, nervousness, emotional depression, allergies, and insomnia. And it’s a dandy way to increase the sale of nutritional supplements.
Simply put, the RDAs protect you against deficiency. If your odd symptoms linger even after you take reasonable amounts of vitamin supplements, probably something other than a lack of any one vitamin is to blame. Don’t wait until your patience or your bank account has been exhausted to find out. Get a second opinion as soon as you can. Table 10-2 lists the symptoms of various vitamin deficiencies.


Choline is not a vitamin, a mineral, a protein, a carbohydrate, or a fat, but it’s usually lumped in with the B-vitamins, so heeeeere’s choline! In 1998, 138 years after this nutrient first was identified, the Institute of Medicine (IOM) finally declared it essential for human beings. The IOM had good reasons for doing so. Choline keeps body cells healthy. It’s used to make acetylcholine, a chemical that enables brain cells to exchange messages. It protects the heart and lowers the risk of liver cancer. And new research at the University of North Carolina (Chapel Hill) shows that choline plays a role in developing and maintaining the ability to think and remember, at least among rat pups and other beasties born to lab animals that were given choline supplements while pregnant. Follow-up studies showed that prenatal choline supplements helped the animals grow bigger brain cells. True, no one knows whether this would also be true for human pups, er, babies, but some researchers advise pregnant women to eat a varied diet, because getting choline from basic stuff like eggs, meat, and milk is so easy. IOM’s Food and Nutrition Board, the group that sets the RDAs, has established an AI (Adequate Intake) for choline.

Pantothenic acid

Pantothenic acid, another B-vitamin, is vital to enzyme reactions that enable you to use carbohydrates and create steroid biochemicals such as hormones. Pantothenic acid also helps stabilize blood sugar levels, defends against infection, and protects hemoglobin (the protein in red blood cells that carries oxygen through the body), as well as nerve, brain, and muscle tissue. You get pantothenic acid from meat, fish and poultry, beans, whole grain cereals, and fortified grain products. As with biotin, the Food and Nutrition Board has established an Adequate Intake (AI) for pantothenic acid.

Understanding Biotin

Biotin is a B-vitamin, a component of enzymes that ferry carbon and oxygen atoms between cells. Biotin helps you metabolize fats and carbohydrates and is essential for synthesizing fatty acids and amino acids needed for healthy growth. And it seems to prevent a buildup of fat deposits that may interfere with the proper functioning of liver and kidneys. (No, biotin won’t keep fat from settling in more visible places, such as your hips.) The best food sources of biotin are liver, egg yolk, yeast, nuts, and beans. If your diet doesn’t give you all the biotin you need, bacteria in your gut will synthesize enough to make up the difference. No RDA exists for biotin, but the Food and Nutrition Board has established an Adequate Intake (AI), which means a safe and effective daily dose.

Understanding Vitamin B12

Vitamin B12 (cyanocobalamin) makes healthy red blood cells. Vitamin B12 protects myelin, the fatty material that covers your nerves and enables you to transmit electrical impulses (messages) between nerve cells. These messages make it possible for you to see, hear, think, move, and do all the things a healthy body does each day. In 2005, the Canadian Medical Association Journal reported that low blood levels of B12 in older people are linked to higher levels of homocysteine (a minor risk factor for heart disease).
Vitamin B12 is unique. First, it’s the only vitamin that contains a mineral, cobalt. (Cyanocobalamin, a cobalt compound, is commonly used as “vitamin B12” in vitamin pills and nutritional supplements.) Second, it’s a vitamin that can’t be made by higher plants (the ones that give us fruits and vegetables). Like vitamin K, vitamin B12 is made by beneficial bacteria living in your small intestine. Meat, fish, poultry, milk products, and eggs are good sources of vitamin B12. Grains don’t naturally contain vitamin B12, but like other B vitamins, it’s added to grain products in the United States.

Wednesday, October 29, 2008


Folate, or folic acid, is an essential nutrient for human beings and other vertebrates (animals with backbones). Folate takes part in the synthesis of DNA, the metabolism of proteins, and the subsequent synthesis of amino acids used to produce new body cells and tissues. Folate is vital for normal growth and wound healing. An adequate supply of the vitamin is essential for pregnant women to enable them to create new maternal tissue as well as fetal tissue. In addition, an adequate supply of folate dramatically reduces the risk of spinal cord birth defects. Beans, dark green leafy vegetables, liver, yeast, and various fruits are excellent food sources of folate, and all multivitamin supplements must now provide 400 mcg of folate per dose.

Vitamin B6 (Pyridoxine)

Vitamin B6 is another multiple compound, this one comprising three related chemicals: pyridoxine, pyridoxal, and pyridoxamine. Vitamin B6, a component of enzymes that metabolizes proteins and fats, is essential for getting energy and nutrients from food. It also helps lower blood levels of homocysteine (see Chapter 6), an amino acid produced when you digest proteins. The American Heart Association calls a high level of homocysteine an independent (but not major) risk factor for heart disease, and the American Journal of Clinical Nutrition reported in 2005 that a high homocysteine level may be associated with an age-related decline in memory. Alas, follow up studies show no reduction in the risk of heart disease or improvement in memory in those who reduce their blood levels of homocysteine.
The best food sources of vitamin B6 are liver, chicken, fish, pork, lamb, milk, eggs, unmilled rice, whole grains, soybeans, potatoes, beans, nuts, seeds, and dark green vegetables such as turnip greens. In the United States, bread and other products made with refined grains have added vitamin B6.


Niacin is one name for a pair of naturally occurring nutrients, nicotinic acid and nicotinamide. Niacin is essential for proper growth, and like other B vitamins, it’s intimately involved in enzyme reactions. In fact, it’s an integral part of an enzyme that enables oxygen to flow into body tissues. Like thiamin, it gives you a healthy appetite and participates in the metabolism of sugars and fats. Niacin is available either as a preformed nutrient or via the conversion of the amino acid tryptophan. Preformed niacin comes from meat; tryptophan comes from milk and dairy foods. Some niacin is present in grains, but your body can’t absorb it efficiently unless the grain has been treated with lime —the mineral, not the fruit. This is a common practice in Central American and South American countries, where lime is added to cornmeal in making tortillas. In the United States, breads and cereals are routinely fortified with niacin. Your body easily absorbs the added niacin. The term used to describe the niacin RDA is NE (niacin equivalent): 60 milligrams tryptophan = 1 milligram niacin = 1 niacin equivalent (NE).

Lemons, limes, oranges — and bacon?

Check the meat label. Right there it is, plain as day — vitamin C in the form of sodium ascorbate or isoascorbate.
The Food and Drug Administration (FDA) says it has to be there because vitamin C does for meat exactly what it does for your body: It prevents free radicals (incomplete pieces of molecules) from hooking up with each other to form damaging compounds, in this case carcinogens, substances that cause cancer.
Processed meats such as bacon and sausages are preserved with sodium nitrite, which protects the meat from Clostridium botulinum, microorganisms that cause the potentially fatal food poisoning known as botulism.
On its own, sodium nitrite reacts at high temperatures with compounds in meat to form carcinogens called nitrosamines. But like the Lone Ranger, antioxidant vitamin C rides to the rescue, preventing the chemical reaction and keeping the sausage and bacon safe to eat. How’s that for healthy eating, Kemo Sabe?

Riboflavin (vitamin B2)

Riboflavin (vitamin B2), the second B vitamin to be identified, was once called “vitamin G.” Its present name is derivative of its chemical structure, a carbon-hydrogen-oxygen skeleton that includes ribitol (a sugar) attached to a flavonoid (a substance from plants containing a pigment called flavone). Like thiamin, riboflavin is a coenzyme. Without it, your body can’t digest and use proteins and carbohydrates. Like vitamin A, it protects the health of mucous membranes — the moist tissues that line the eyes, mouth, nose, throat, vagina, and rectum. You get riboflavin from foods of animal origin (meat, fish, poultry, eggs, and milk), whole or enriched grain products, brewer’s yeast, and dark green vegetables (like broccoli and spinach).

Thiamin (vitamin B1)

Call it thiamin. Call it B1. Just don’t call it late for lunch (or any other meal). This sulfur (thia) and nitrogen (amin) compound, the first of the B vitamins to be isolated and identified, helps ensure a healthy appetite. It acts as a coenzyme (a substance that works along with other enzymes) essential to at least four different processes by which your body extracts energy from carbohydrates. And thiamin also is a mild diuretic (something that makes you urinate more).
Although thiamin is found in every body tissue, the highest concentrations are in your vital organs — heart, liver, and kidneys. The richest dietary sources of thiamin are unrefined cereals and grains, lean pork, beans, nuts, and seeds. In the United States, refined flours, stripped of their thiamin, are a nutritional reality, so most Americans get most of their thiamin from breads and cereals enriched with additional B1.

Wednesday, October 15, 2008

Vitamin C

Vitamin C, which also is referred to as ascorbic acid, is essential for the development and maintenance of connective tissue (the fat, muscle, and bone framework of the human body). Vitamin C speeds the production of new cells in wound healing, protects your immune system, helps you fight off infection, reduces the severity of allergic reactions, and plays a role in the syntheses of hormones and other body chemicals.

Water-soluble vitamins

Vitamin C and the entire roster of B vitamins (thiamin, riboflavin, niacin, vitamin B6, folate, biotin, and pantothenic acid) are usually grouped together simply because they all dissolve in water. The ability to dissolve in water is an important point, because that means large amounts of these nutrients can’t be stored in your body. If you take in more than you need to perform specific bodily tasks, you will simply pee away virtually all the excess. The good news is that these vitamins rarely cause side effects. The bad news is that you have to take enough of these vitamins every day to protect yourself against deficiencies.

PQQ, a new kind of vitamin

The next time someone tells you to mind your p’s and q’s, don’t take offense. The subject may be nutrition, not manners — pyrroloquinoline quinone (PQQ), the first new vitamin in more than half a century. The water-soluble compound, identified at the University of Texas in 1979 and labeled a vitamin four years later by researchers at Tokyo’s Institute of Physical and Chemical Research, is widely available in plant foods such as green tea, green bell peppers, papaya, spinach, carrots, cabbage, and bananas. Animal studies show a connection between PQQ and an enzyme used by mammals to digest lysine, an amino acid found in proteins. The vitamin is essential for some bacteria and maybe even mice. And you? Well, if you need it, you need very, very little. The amounts of other vitamins are measured in milligrams (thousandths of a gram) or micrograms (millionths of a gram). But PQQ is measured in nanograms (billionths of a gram) — 1/1,000,000,000.Which is about as itty-bitty as it gets.

Sunday, September 21, 2008

Understanding Vitamin K

Vitamin K is a group of chemicals that your body uses to make specialized proteins found in blood plasma (the clear fluid in blood), such as prothrombin, the protein chiefly responsible for blood clotting. You also need vitamin K to make bone and kidney tissues. Like vitamin D, vitamin K is essential for healthy bones. Vitamin D increases calcium absorption; vitamin K activates at least three different proteins that take part in forming new bone cells. For example, a report on 888 men and women from the long-running Framingham (Massachusetts) Heart Study shows that those who consumed the least vitamin K each day had the highest incidence of broken bones. The same was true for a 1999 analysis of data from the Nurses’ Health Study. Vitamin K is found in dark green leafy vegetables (broccoli, cabbage, kale, lettuce, spinach, and turnip greens), cheese, liver, cereals, and fruits, but most of what you need comes from resident colonies of friendly bacteria in your intestines, an assembly line of busy bugs churning out the vitamin day and night.

Understanding Vitamin E

Every animal, including you, needs vitamin E to maintain a healthy reproductive system, nerves, and muscles. You get vitamin E from tocopherols and tocotrienols, two families of naturally occurring chemicals in vegetable oils, nuts, whole grains, and green leafy vegetables — your best natural sources of vitamin E.
Tocopherols, the more important source, have two sterling characteristics: They’re anticoagulants and antioxidants that reduce blood’s ability to clot, thus reducing the risk of clot-related stroke and heart attack. Antioxidants prevent free radicals (incomplete pieces of molecules) from hooking up with other molecules or fragments of molecules to form toxic substances that can attack tissues in your body. In fact, nutrition scientists at Purdue University released a study showing that vitamin E promotes bone growth by stopping free radicals from reacting with polyunsaturated fatty acids to create molecules that interfere with the formation of new bone cells.
But some claims about E’s heart health benefits are now considered iffy. True, a recent clinical trial at Cambridge University in England showed that taking 800 IU (International Units) of vitamin E, two times the RDA, may reduce the risk of nonfatal heart attacks for people who already have heart disease. And, yes, the federal Women’s Health Study found that older women taking 600 IU vitamin E per day had a lower risk of heart attack and a lower risk of death from heart disease. But the Heart Outcomes Prevention Evaluation (HOPE) study showed no such benefits. In fact, people taking 400 IU per day vitamin E were more likely to develop heart failure. No one (and no study) has found similar problems among those taking less vitamin E, say 100 IU/day. Whew. The best sources of vitamin E are vegetables, oils, nuts, and seeds. The RDA is expressed as milligrams a-tocopherol equivalents (abbreviated as a-TE).

Understanding Vitamin D

If I say “bones” or “teeth,” what nutrient springs most quickly to mind? If you answer calcium, you’re giving only a partial picture. True, calcium is essential for hardening teeth and bones. But no matter how much calcium you consume, without vitamin D, your body can’t absorb and use the mineral. So vitamin D is vital for building — and holding — strong bones and teeth.
Researchers at the Bone Metabolism Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston say vitamin D may also reduce the risk of tooth loss by preventing the inflammatory response that leads to periodontal disease, a condition that destroys the thin tissue (ligaments) that connects the teeth to the surrounding jawbone.
Finally, a report in the February 2006 issue of The American Journal of Public Health suggests that taking 1,000 international units (IU) of vitamin D a day may cut in half a person’s risk of developing some forms of cancer, including cancer of the colon, breast, or ovaries.
Vitamin D comes in three forms: calciferol, cholecalciferol, and ergocalciferol. Calciferol occurs naturally in fish oils and egg yolk. In the United States, it’s added to margarines and milk. Cholecalciferol is created when sunlight hits your skin and ultraviolet rays react with steroid chemicals in body fat just underneath. Ergocalciferol is synthesized in plants exposed to sunlight. Cholecalciferol and ergocalciferol justify vitamin D’s nickname: the Sunshine Vitamin. The RDA for vitamin D is measured either in International Units (IUs) or micrograms (mcg) of cholecalciferol: 10 mcg cholecalciferol = 400 IU vitamin D.

Monday, September 8, 2008

Help! I’m turning orange - Carotenoids overdose

Because you store retinol in your liver, megadoses of preformed vitamin A can build up to toxic levels. Not so with carotenoids, which serve up another form of that vitamin. They aren’t stored in the liver, so these red and yellow pigments in fruits and vegetables are safe even in very large amounts.
But that doesn’t mean that excess carotenoids don’t have side effects. Carotenoids, like retinoids, are stored in body fat. If you wolf down large quantities of carotenoid-rich foods like carrots and tomatoes every day, day after day, for several weeks, your skin — particularly the palms of your hands and the soles of your feet — will turn a nifty shade of dusty orange, brighter if your skin is naturally light, darker if it’s naturally dark. It sounds fantastic, but it has actually happened to people eating two cups of carrots and two whole tomatoes a day for several months. When they cut down on the carrots and tomatoes, the color faded.
Now, let’s see . . . it’s September 8, and you’ve been invited to a Halloween party. Maybe this year you’ll go as a pumpkin. If you start packing in the carrots and tomatoes right now. . . .

Understanding Vitamin A

Vitamin A is the moisturizing nutrient that keeps your skin and mucous membranes (the slick tissue that lines the eyes, nose, mouth, throat, vagina, and rectum) smooth and supple. Vitamin A is also the vision vitamin, a constituent of 11-cis retinol, a protein in the rods (cells in the back of your eye that enable you to see even when the lights are low) that prevents or slows the development of age-related macular degeneration, or progressive damage to the retina of the eye, which can cause the loss of central vision (the ability to see clearly enough to read or do fine work). Finally, vitamin A promotes the growth of healthy bones and teeth, keeps your reproductive system humming, and encourages your immune system to churn out the cells you need to fight off infection.
Two chemicals provide vitamin A: retinoids and carotenoids. Retinoids are compounds whose names all start with ret: retinol, retinaldehyde, retinoic acid, and so on. These fat-soluble substances are found in several foods of animal origin: liver (again!) and whole milk, eggs, and butter. Retinoids give you preformed vitamin A, the kind of nutrient your body can use right away. The second form of vitamin A is the vitamin A precursor, a chemical such as beta-carotene, a deep yellow carotenoid (pigment) found in dark green and bright yellow fruits and vegetables. Your body transforms a vitamin A precursor into a retinol-like substance. So far, scientists have identified at least 500 different carotenoids. Only 1 in 10 — about 50 altogether — are considered, like beta-carotene, to be sources of vitamin A.
Traditionally, the recommended dietary allowances of vitamin A are measured in International Units (IU). However, because retinol is the most efficient source of vitamin A, the modern way to measure the RDA for vitamin A is as retinol equivalents, abbreviated as RE. One microgram (mcg) RE = 3.3 IU. However, many vitamin products still list the RDA for vitamin A in IUs.

The father of all vitamins: Casimir Funk

Vitamins are so much a part of modern life you may have a hard time believing they were first discovered less than a century ago. Of course, people have long known that certain foods contain something special. For example, the ancient Greek physician Hippocrates prescribed liver for night-blindness (the inability to see well in dim light). By the end of the 18th century (1795), British Navy ships carried a mandatory supply of limes or lime juice to prevent scurvy among the men, thus earning the Brits once and forever the nickname limeys. Later on, the Japanese Navy gave its sailors whole grain barley to ward off beriberi.
Everyone knew these prescriptions worked, but nobody knew why — until 1912, when Casimir Funk (1884–1967), a Polish biochemist working first in England and then in the United States, identified “somethings” in food that he called vitamines (vita = life; amines = nitrogen compounds).
The following year, Funk and a fellow biochemist, Briton Frederick Hopkins, suggested that some medical conditions such as scurvy and beriberi were simply deficiency diseases caused by the absence of a specific nutrient in the body. Adding a food with the missing nutrient to one’s diet would prevent or cure the deficiency disease.

Understanding Vitamins

Your body needs at least 11 specific vitamins: vitamin A, vitamin D, vitamin E, vitamin K, vitamin C, and the members of the B vitamin family: thiamin (vitamin B1), riboflavin (B2), niacin, vitamin B6, folate, and vitamin B12. Two more B vitamins — biotin and pantothenic acid — are now believed valuable to your well-being as well. And one unusual compound called choline has recently received some favorable mention. You need only miniscule quantities of vitamins for good health.
In some cases, the recommended dietary allowances (RDAs), determined by the National Research Council, may be as small as several micrograms (1⁄1,000,000 – that’s one one-millionth — of a gram). Nutritionists classify vitamins as either fat soluble or water soluble, meaning that they dissolve either in fat or in water. If you consume larger amounts of fat-soluble vitamins than your body needs, the excess is stored in body fat. Excess water-soluble vitamins are eliminated in urine. Large amounts of fat-soluble vitamins stored in your body may cause problems. With watersoluble vitamins, your body simply shrugs its shoulders, so to speak, and urinates away most of the excess.
Medical students often use mnemonic devices — memory joggers — to remember complicated lists of body parts and symptoms of diseases. Here’s one I use to remember which vitamins are fat-soluble: “All Dogs Eat Kidneys.” This saying helps me remember that vitamins A, D, E, and K are fat-soluble.
All the rest dissolve in water.

The power of purple grapes (and peanuts)

Grape skin, pulp, and seeds contain resveratrol, a naturally occurring plant chemical that seems to reduce the risk of heart disease and some kinds of cancer. The darker the grapes, the higher the concentration of resveratrol. Dark purple grape juice, for example, has more resveratrol than red grape juice, which has more resveratrol than white grape juice. Because wine is made from grapes, it, too, contains resveratrol (red wine has more resveratrol than white wine).
But you don’t need to drink grape juice or wine to get resveratrol. You can simply snack on peanuts. Yes, peanuts. A 1998 analysis from the USDA Agricultural Research Service in Raleigh, North Carolina, showed that peanuts have 1.7 to 3.7 micrograms of resveratrol per gram of nuts. Compare that to the 0.7 micrograms of resveratrol in a glass of red grape juice or 0.6 to 8.0 micrograms of resveratrol per gram of red wine. This fact may explain data from the longrunning Harvard University/Brigham and Women’s Hospital Nurses’ Health Study, which shows that women who eat an ounce of nuts a day have a lower risk of heart disease. So let’s see — wine, grape juice, peanuts . . . decisions, decisions.

Monday, August 25, 2008

Binge drinking: A behavioral no-no

Binge drinkers are “once-in-a-while alcoholics.” They don’t drink every day, but when they do indulge, they go so far overboard that they sometimes fail to come back up. In simple terms, binge drinking is downing very large amounts of alcohol in a short time, not for a pleasant lift but to get drunk. As a result, binge drinkers may consume so much beer, wine, or spirits that the amount of alcohol in their blood rises to lethal levels, leading to death by alcohol poisoning. Got the picture? Binge drinking is not a sport. It’s potentially fatal behavior. Don’t do it.

The power of purple (and peanuts)

Grape skin, pulp, and seeds contain resveratrol, a naturally occurring plant chemical that seems to reduce the risk of heart disease and some kinds of cancer. The darker the grapes, the higher the concentration of resveratrol. Dark purple grape juice, for example, has more resveratrol than red grape juice, which has more resveratrol than white grape juice. Because wine is made from grapes, it, too, contains resveratrol (red wine has more resveratrol than white wine).
But you don’t need to drink grape juice or wine to get resveratrol. You can simply snack on peanuts. Yes, peanuts. A 1998 analysis from the USDA Agricultural Research Service in Raleigh, North Carolina, showed that peanuts have 1.7 to 3.7 micrograms of resveratrol per gram of nuts. Compare that to the 0.7 micrograms of resveratrol in a glass of red grape juice or 0.6 to 8.0 micrograms of resveratrol per gram of red wine.
This fact may explain data from the longrunning Harvard University/Brigham and Women’s Hospital Nurses’ Health Study, which shows that women who eat an ounce of nuts a day have a lower risk of heart disease. So let’s see — wine, grape juice, peanuts . . . decisions, decision

A lot and a little versus the middle

When scientists talk about the relationship between alcohol and heart disease, the words J-curve often pop up. What’s a J-curve? A statistical graph in the shape of the letter J.
In terms of heart disease, the lower peak on the left of the J shows the risk among teetotalers, the high spike on the right shows the risk among those who drink too much, and the curve in the center shows the risk in the moderate middle. In other words, the J-curve says that people who drink moderately have a lower risk of heart disease than people who drink too much or not at all.

That info’s nice. This is better: According to a recent report from the Alberta (Canada) Alcohol and Drug Abuse Commission, the J-curve may also describe the relationship between alcohol and stroke, alcohol and diabetes, alcohol and bone loss, and alcohol and longevity. The simple fact is that moderate drinkers appear to live longer, healthier lives than either teetotalers or alcohol abusers. Cheers!

Who should not drink

No one should drink to excess. But some people shouldn’t drink at all, not even in moderation. They include
  • People who plan to drive or do work that requires both attention and skill. Alcohol slows reaction time and makes your motor skills — turning the wheel of the car, operating a sewing machine — less precise.
  • Women who are pregnant or who plan to become pregnant in the near future. Fetal alcohol syndrome (FAS) is a collection of birth defects including low birth weight, heart defects, retardation, and facial deformities documented only in babies born to female alcoholics. No evidence links FAS to casual drinking — that is, one or two drinks during a pregnancy or even one or two drinks a week. But the fact is that about 7 percent of the babies born in the United States each year are born with birth defects independent of any parental behavior. The parents of these children may feel guilty, even though their behavior had absolutely nothing to do with the birth defect. Your decision about alcohol should take into consideration the possibility of (misplaced) lifelong guilt caused by having had a drink.
  • People who take certain prescription drugs or over-the-counter medication. Alcohol makes some drugs stronger, increases some drugs’ side effects, and renders other drugs less effective. At the same time, some drugs make alcohol a more powerful sedative or slow down the elimination of alcohol from your body.

Alcoholism: An addiction disease

Alcoholics are people who can’t control their drinking. Untreated alcoholism is a life-threatening disease that can lead to death either from an accident or suicide (both are more common among heavy drinkers) or from a toxic reaction (acute alcohol poisoning that paralyzes body organs, including the heart and lungs) or malnutrition or liver damage (cirrhosis). Alcoholism makes it extremely difficult for the body to get essential nutrients.
Here’s why:
  • Alcohol depresses appetite.
  • An alcoholic may substitute alcohol for food, getting calories but no nutrients.
  • Even when the alcoholic eats, the alcohol in his or her tissues can prevent the proper absorption of vitamins (notably the B vitamins), minerals, and other nutrients.
  • Alcohol may also reduce the alcoholic’s ability to synthesize proteins.
No one knows exactly why some people are able to have a drink once a day or once a month or once a year, enjoy it, and move on, while others become addicted to alcohol. In the past, alcoholism has been blamed on heredity (bad genes), lack of willpower, or even a bad upbringing. But as science continues to unravel the mysteries of body chemistry, it’s reasonable to expect that researchers will eventually come up with a rational scientific explanation for the differences between social drinkers and people who can’t safely use alcohol. It just hasn’t happened yet.

Sunday, August 10, 2008

The physical risks of alcohol abuse

Alcohol abuse is a term generally taken to mean drinking so much that it interferes with your ability to have a normal, productive life. The short-term effects of excessive drinking are well-known to one and all, especially to men who may find that drinking too much decreases sexual desire and makes it impossible to . . . well . . . perform. (No evidence suggests that excessive drinking interferes with female orgasm.)
Excessive drinking can also make you feel terrible the next day. The morning after is not fiction. A hangover is a miserable physical fact:
  • You’re thirsty because you lost excess water through copious urination.
  • Your stomach hurts and you’re queasy because even small amounts of alcohol irritate your stomach lining, causing it to secrete extra acid and lots of histamine, the same immune system chemical that makes the skin around a mosquito bite red and itchy.
  • Your muscles ache and your head pounds because processing alcohol through your liver requires an enzyme — nicotinamide adenine dinucleotide (NAD) — normally used to convert lactic acid, a byproduct of muscle activity, to other chemicals that can be used for energy. The extra, unprocessed lactic acid piles up painfully in your muscles.

Moderate drinking: Some benefits, some risks

Moderate amounts of alcohol reduce stress, so it isn’t surprising that recent well-designed scientific studies on large groups of men and women suggest that moderate drinking is heart-healthy, protecting the cardiovascular system (that’s science talk for heart and blood vessels). Here are some findings about the cardiovascular benefits and some of the other things moderate drinking can do for you:
  • The American Cancer Society’s Cancer Prevention Study 1 followed more than one million Americans in 25 states for 12 years to find that moderate alcohol intake had an “apparent protective effect on coronary heart disease.” Translation: Men who drink moderately lower their risk of heart attack. The risk is 21 percent lower for men who have one drink a day than for men who never drink. A similar analysis of data for nearly 600,000 women in the long-running (Harvard) Nurses’ Health Study showed that women who drink occasionally or have one drink a day are less likely to die of heart attack than those who don’t drink at all.
  • A 2003 study at Tulane University School of Public Health and Tropical Medicine shows that men who drink moderately (two drinks a day) also are less likely to die of clot-related stroke. But because alcohol reduces blood clotting, it increases the risk of hemorrhagic stroke (stroke caused by bleeding in the brain). Sorry about that.
  • According to researchers at USDA’s Agricultural Research Service (ARS) laboratory at Beltsville, Maryland, moderate drinking may lower a healthy older woman’s risk of developing diabetes.
  • Contrary to popular opinion, a 15-year, 1,700-person heart disease study at the Institute of Preventive Medicine, Kommunehospitalet in Copenhagen, Denmark, showed that older men and women who regularly consumed up to 21 drinks of wine a week were less likely than teetotalers to develop Alzheimer’s disease and other forms of dementia. Similarly, a recent 12-year, 1,488-person survey at Johns Hopkins University in Maryland suggests that regular, moderate drinkers score better over time than teetotalers do on the Mini-Mental State Examination (MMSE), a standard test for memory, reasoning, and decision making. That’s the good news. Here’s the bad news: The same studies that applaud the effects of moderate drinking on heart health are less reassuring about the relationship between alcohol and cancer: The American Cancer Society’s Cancer Prevention Study 1 shows that people who take more than two drinks a day have a higher incidence of cancer of the mouth and throat (esophagus). In addition;
  • Researchers at the University of Oklahoma say that men who drink five or more beers a day double their risk of rectal cancer.
  • American Cancer Society statistics show a higher risk of breast cancer among women who have more than three drinks a week, but newer studies suggest this effect may apply only to older women using hormone replacement therapy.

Alcohol and Brain

Alcohol is a sedative. When it reaches your brain, it slows the transmission of impulses between nerve cells that control your ability to think and move. That’s why your thinking may be fuzzy, your judgment impaired, your tongue twisted, your vision blurred, and your muscles rubbery. Do you feel a sudden urge to urinate? Alcohol reduces your brain’s production of antidiuretic hormones, chemicals that keep you from making too much urine. You may lose lots of liquid, plus vitamins and minerals. You also grow very thirsty, and your urine may smell faintly of alcohol.

This cycle continues as long as you have alcohol circulating in your blood, or in other words, until your liver can manage to produce enough ADH to metabolize all the alcohol you’ve consumed. How long is that? Most people need an hour to metabolize the amount of alcohol (1⁄2 ounce) in one drink. But that’s an average: Some people have alcohol circulating in their blood for up to three hours after taking a drink.

Rising to the surface

In your blood, alcohol raises your level of high-density lipoproteins (HDLs), although not necessarily the specific good ones that carry cholesterol out of your body. Alcohol also makes blood less likely to clot, temporarily reducing your risk of heart attack and stroke.
Alcohol makes blood vessels expand, so more warm blood flows up from the center of your body to the surface of the skin. You feel warmer for a while and, if your skin is fair, you may flush and turn pink. (Asians, who — you may remember from a few paragraphs back — tend to make less alcohol dehydrogenase than do Caucasians, often experience a characteristic flushing when they drink even small amounts of alcohol.) At the same time, tiny amounts of alcohol ooze out through your pores, and your perspiration smells of alcohol.

Taking time out for air

Entering your heart, alcohol reduces the force with which your heart muscle contracts. You pump out slightly less blood for a few minutes, blood vessels all over your body relax, and your blood pressure goes down temporarily. The contractions soon return to normal, but the blood vessels may remain relaxed and your blood pressure lower for as long as half an hour. At the same time, alcohol flows in blood from your heart through your pulmonary vein to your lungs. Now you breathe out a tiny bit of alcohol every time you exhale, and your breath smells of liquor. Then the newly oxygenated, still alcohol-laden blood flows back through the pulmonary artery to your heart, and up and out through the aorta (the major artery that carries blood out to your body).

Stopping for a short visit at the energy factory

Most of the alcohol you drink is absorbed through the duodenum (small intestine), from which it flows through a large blood vessel (the portal vein) into your liver. There, an enzyme similar to gastric ADH metabolizes the alcohol, which is converted to energy by a coenzyme called nicotinamide adenine dinucleotide (NAD). NAD is also used to convert the glucose you get from other carbohydrates to energy; while NAD is being used for alcohol, glucose conversion grinds to a halt.
The normal, healthy liver can process about 1⁄2 ounce of pure alcohol (that’s 6 to 12 ounces of beer, 5 ounces of wine, or 1 ounce of spirits) in an hour. The rest flows on to your heart.

Monday, July 21, 2008

What alcohol do in your mouth and stomach?

Alcohol is an astringent; it coagulates proteins on the surface of the lining of your mouth to make it “pucker.” Some alcohol is absorbed through the lining of your mouth and throat, but most of the alcohol you drink spills into your stomach, where an enzyme called gastric alcohol dehydrogenase (ADH) begins to metabolize (digest) it.
How much alcohol dehydrogenase your body churns out is influenced by your ethnicity and your gender. For example, Asians, Native Americans, and Inuits appear to secrete less alcohol dehydrogenase than do most Caucasians, and the average woman (regardless of her ethnicity) makes less ADH than the average man does. As a result, more unmetabolized alcohol flows from their tummies into their bloodstreams, and they’re likely to become tipsy on smaller amounts of alcohol than an average Caucasian male would need to drink. While you ponder that, the unmetabolized alcohol is flowing through your stomach walls into your bloodstream and on to your small intestine.

How Much Alcohol Is in That Bottle?

No alcohol beverage is 100 percent alcohol. It’s alcohol plus water, and — if it’s a wine or beer — some residue of the foods from which it was made. The label on every bottle of wine and spirits shows the alcohol content as alcohol by volume (ABV). (For reasons too complicated to discuss in fewer than, say, 50 pages, beer containers may carry this information, but United States law doesn’t require it.)
ABV measures the amount of alcohol as a percentage of all the liquid in the container. For example, if your container holds 10 ounces of liquid and 1 ounce of that is alcohol, the product is 10 percent ABV — the alcohol content divided by the total amount of liquid.
Proof — an older term that describes alcohol content —is two times the ABV. For example, an alcohol beverage that is 10 percent alcohol by volume is 20 proof.
By the way, right now, alcohol beverages are the only entries in the food and drink market sold without a Nutrition Facts label. The National Consumers League and the Washington-based Center for Science in the Public Interest are petitioning the Food and Drug Administration to create an ingredients label for alcohol beverages. The label would show the ingredients, the number of standard servings in the container, and the alcohol content and calorie count per serving so you can compare products — and control what you drink. Smart. To see the proposed label, visit

The foods used to make beverage alcohol

Beverage alcohol can be made from virtually any carbohydrate food. The foods most commonly used are cereal grains, fruit, honey, molasses, or potatoes. All produce alcohol, but the alcohols have slightly different flavors and colors.
On its own, alcohol provides energy (7 calories per gram) but no nutrients, so distilled spirits, such as whiskey or plain, unflavored vodka serve up nothing but calories. Beer, wine, cider, and other fermented beverages, such as kumiss (fermented milk), contain some of the food from which they were made, so they contain small amounts of proteins and carbohydrates, vitamins, and minerals.

Distilled alcohol products

The second way to make an alcohol beverage is through distillation.
As with fermentation, yeasts are added to foods to make alcohol from sugars. But yeasts can’t thrive in a place where the concentration of alcohol is higher than 20 percent. To concentrate the alcohol and separate it from the rest of the ingredients in the fermented liquid, distillers pour the fermented liquid into a still, a large vat with a wide column-like tube on top. The still is heated so that the alcohol, which boils at a lower temperature than everything else in the vat, turns to vapor, which rises through the column on top of the still, to be collected in containers where it condenses back into a liquid. This alcohol, called neutral spirits, is the base for the alcohol beverages called spirits or distilled spirits: gin, rum, tequila, whiskey, and vodka. Brandy is a special product, a spirit distilled from wine. Fortified wines such as Port and Sherry are wines with spirits added.

Tuesday, July 8, 2008

Fermented alcohol products

Fermentation is a simple process in which yeasts or bacteria are added to carbohydrate foods such as corn, potatoes, rice, or wheat, which are used as starting material. The yeasts digest the sugars in the food, leaving liquid (alcohol); the liquid is filtered to remove the solids, and water is usually added to dilute the alcohol, producing — voilĂ  — an alcohol beverage. Beer is made this way. So is wine. Kumiss, a fermented milk product, is slightly different because it’s made by adding yeasts and friendly bacteria called lactobacilli (lacto = milk) to mare’s milk. The microorganisms make alcohol, but it isn’t separated from the milk, which turns into a fizzy fermented beverage with no water added.