Sunday, April 27, 2008

Nutrition Mini Quiz

By Gwen Schoen

Most of us know that eating fruit is a good boost for your health, but does that mean you should just plop an apple into your lunch sack every day and call it nutrition accomplished? Here's a quiz to find out if you are making the best choices when it comes to fruit.

1. Figs are higher in potassium than bananas.

True or false?

2. Figs are excellent sources of calcium.

True or false?

3. A recent study shows that lychee may help prevent the formation of breast cancer cells due to its powerful antioxidant activity.

True or false?

4. Oranges have more vitamin C than guava.

True or false?

5. Guava can protect against food-borne pathogens such as listeria.

True or false?

6. Apples are high in fiber, which helps lower cholesterol.

True or false?

7. Apples have more fiber than Asian pears.

True or false?

8. Watermelon and papaya are rich sources of lycopene.

True or false?

9. Rubbing a slice of papaya on a sunburn will help your skin to heal faster.

True or false?

Source: May 2008 issue of Prevention magazine

Answers: 1. True; 2. True; 3. True; 4. False; 5. True; 6. True; 7. False; 8. True; 9. True.

Fat In the body

Glucose, the molecule you get by digesting carbohydrates, is the body’s basic source of energy. Burning glucose is easier and more efficient than burning fat, so your body always goes for carbohydrates first. But if you’ve used up all your available glucose — maybe you’re stranded in a cabin in the Arctic, you haven’t eaten for a week, a blizzard’s howling outside, and the corner deli 500 miles down the road doesn’t deliver — then it’s time to start in on your body fat. The first step is for an enzyme in your fat cells to break up stored triglycerides (the form of fat in adipose tissue).

The enzyme action releases glycerol and fatty acids, which travel through your blood to body cells, where they combine with oxygen to produce heat/energy, plus water — lots of water —and the waste product carbon dioxide. As anyone who has used a highprotein/ high-fat/low-carb weight-loss diet such as the Atkins regimen can tell you, in addition to all that water, burning fat without glucose produces a second waste product called ketones. In extreme cases, high concentrations of ketones (a condition known as ketosis) alter the acid/alkaline balance (or pH) of your blood and may trip you into a coma. Left untreated, ketosis can lead to death. Medically, this condition is most common among people with diabetes. For people on a low-carb diet, the more likely sign of ketosis is stinky urine or breath that smells like acetone (nail polish remover).

Fat in the intestines

When the fat moves down your digestive tract into your small intestine, an intestinal hormone called cholestokinin beeps your gallbladder, signaling for the release of bile. Bile is an emulsifier, a substance that enables fat to mix with water so that lipases can start breaking the fat into glycerol and fatty acids. These smaller fragments may be stored in special cells (fat cells) in adipose tissue, or they may be absorbed into cells in the intestinal wall, where one of the following happens:
  • They’re combined with oxygen (or burned) to produce heat/energy, water, and the waste product carbon dioxide.
  • They’re used to make lipoproteins that haul fats, including cholesterol, through your bloodstream.

Wednesday, April 23, 2008

Nutrition: Should you eat organic?

Should you eat organic? This being Earth Day and all, I'd love to answer that million-dollar question with a few irrefutable facts (for one side or the other), leaving everyone feeling satisfied that the choice (one way or another) is easy. But the reality is that this simple question has a very, very complex answer.

Taken at face value, the answer is a simple one: For both environmental and health reasons, you should probably eat organic whenever possible. By choosing organic foods, you reduce your intake of pesticides, herbicides and other chemicals (whether as part of the growing process for fruits and vegetables, or as part of the feed for animal-based foods), and you also reduce their use in farming, which in turn helps the environment.

On the other hand, many individuals will choose organic foods based on their perception that they are somehow more nutritious than their non-organic counterparts. At this point, however, there is virtually no evidence that this is the case (note, however, that at least one study has shown an increase in the anti-oxidant content of foods grown in soil that has been organically farmed for several years, leading researchers to speculate that gradual improvements in the soil's quality may eventually get passed into the food over time). And though your tongue may tell you different, there is no solid evidence that organic foods taste any better.

So if you're looking to reduce the pesticide load for yourself and the Earth, it seems that you have a pretty straightforward choice. But once you start to factor the carbon footprint issue into the picture, things get pretty muddy. Are you better off to choose an organic plum from Chile, or a locally grown, conventionally farmed apple?

The first problem with that question is that there's no clear way to define what "better off" means. Is it better for the environment to use fewer pesticides in farming, but to transport the food by carbon-spewing airplane across many thousands of miles? Or is it better to buy food that may have been exposed to some type of chemical, but has only a few hundred kilometres to travel by transport truck?

And what about other resources not factored into the organic designation, like water and energy use? Perhaps the organic option requires a much greater input of water and fertilizer, or requires vast amounts of energy to produce (as with meats, organic or not)? Suddenly the organic choice doesn't seem so pristine. But the same apply to locally grown foods, and the energy needs for either type of food will increase significantly if the product requires processing before it reaches the shelf. For example, that same locally grown apple might see its carbon footprint increased if it needs to be shipped from Ontario to Quebec and back again to be turned into applesauce.

Before you throw in the towel and say "forget it -- as long as China is opening X number of coal mines per day, then it really doesn't matter what I do anyway, so I'm going to buy a huge T-bone steak and a pineapple from Thailand and not care a hoot about it," remember that these answers are not readily available to the average consumer.
At this point, there really is no way you can know whether the carbon footprint for that bag of organic milk is less than for the non-organic milk, or that the cow was treated better or lived a more fulfilled life. As I said off the top, this is a very complicated situation -- and there are many great minds debating the issue to achieve some level of consensus that will be practical for the consumer.

So, in the interim, what can a savvy, modern-day shopper do? For starters, print and clip the attached sidebar and put it on the fridge:
  1. Buy food in season, when you can. And if you have the option, try growing some food of your own.
  2. Eat fewer processed foods. They're much more energy efficient to produce and generally better for you.
  3. When you do buy food in season, consider freezing some of it, especially if it's a favourite that you eat frequently and have to buy out of season for the rest of the year. For instance, now's the time to start stockpiling blueberries.
  4. At the same time, don't go too crazy on the freezing, as a large amount of resources (about 20% of the total energy requirements for a given food, from seed to sewage treatment or compost transport) are spent on household energy use to store and prepare our food; in other words, don't plug in an extra couple of freezers to hold your summer bounty. Also, avoid mega-bulk purchasing, which not only requires extra energy for storage, but tends to lead to overeating and gradual weight gain.
  5. Buy only what you need. All of this discussion is moot if you throw out half of your food. That said, don't teach yourself to overeat just for the sake of saving a buck, or because your mom told you to always clean your plate -- just try smaller portions!
  6. And if you don't eat everything you buy, at least use a composter or organic waste bin for whatever's left.

• Jennifer Sygo is a dietitian in private practice at Cleveland Clinic Canada, which offers executive physicals, prevention and wellness counselling and personal health care management in Toronto.

Pulling energy from fat

Although fat has more energy (calories) per gram than proteins and carbohydrates, your body has a more difficult time pulling the energy out of fatty foods. Imagine a chain of long balloons — the kind people twist into shapes that resemble dachshunds, flowers, and other amusing things. When you drop one of these balloons into water, it floats. That’s exactly what happens when you swallow fat-rich foods. The fat floats on top of the watery food-and-liquid mixture in your stomach, which limits the effect that lipases — fat-busting digestive enzymes in the mix below — can have on it. Because fat is digested more slowly than proteins and carbohydrates, you feel fuller (a condition called satiety) longer after eating high-fat food.

Understanding how your body uses fat

Here’s a sentence that you probably never thought you’d read: A healthy body needs fat. Your body uses dietary fat (the fat that you get from food) to make tissue and manufacture biochemicals, such as hormones. Some of the body fat made from food fat is visible. Even though your skin covers it, you can see the fat in the adipose (fatty) tissue in female breasts, hips, thighs, buttocks, and belly or male abdomen and shoulders.

Visible body fat
  • Provides a source of stored energy
  • Gives shape to your body
  • Cushions your skin (imagine sitting in a chair for a while to read this book without your buttocks to pillow your bones)
  • Acts as an insulation blanket that reduces heat loss
Other body fat is invisible. You can’t see this body fat because it’s tucked away in and around your internal organs. This hidden fat is part of every cell membrane (the outer skin that holds each cell together)
  • A component of myelin, the fatty material that sheathes nerve cells and makes it possible for them to fire the electrical messages that enable you to think, see, speak, move, and perform the multitude of tasks natural to a living body; brain tissue also is rich in fat
  • A shock absorber that protects your organs (as much as possible) if you fall or are injured
  • A constituent of hormones and other biochemicals, such as vitamin D and bile

Saturday, April 19, 2008

Facts About Children's Nutrition

Cheryl Forberg offers these facts about children's nutrition. You can also check out her advice/suggestions regarding healthy kids' snacks and exercise routines in the new Kids' Corner section of the Diet Center!

1.On average, children ages 11-18 eat at fast food restaurants twice a week.

2.When children and teens eat fast food, they consume more calories, fat, carbohydrates, added sugars and sugar-sweetened beverages. They also consume less fiber and milk, and fewer fruits and non-starchy vegetables.

3.At least 30 minutes of moderate physical activity on most days of the week is the recommended minimum. However, only 23% of children and nearly 40% of adults get no free-time physical activity at all.

4.A national study reports that only 8% of elementary schools, 6.4% of middle/junior high schools, and 5.8% of senior high schools provide daily physical education or its equivalent (150 minutes per week for elementary schools, 225 minutes per week for middle/junior and senior high schools is advised) for the entire school year for students in all grades in the school.

5.Six out of 10 children ages 9-13 don't participate in any kind of organized sports/physical activity program outside of school, and children whose parents have lower incomes and education levels are even less likely to participate. Nearly 23% don't engage in any free-time physical activity.

6.Among children and teens aged 6-19 in the US, 16% (over 9 million) are considered overweight.

7.Among children ages 2-5, the prevalence of overweight has increased from 7% to more than 10% since 1994.

8.The obesity epidemic threatens everyone, but not everyone is equally at risk. Among children and adolescents, obesity is more common among African Americans and Hispanics.

9.Most overweight children have at least one major physiological risk factor (besides overweight) for cardiovascular disease, such as high cholesterol, high triglycerides, high insulin or high blood pressure.

10.Overweight adolescents have a 70% chance of becoming overweight or obese adults. This increases to 80% if one or more parent is overweight or obese.

11.Overweight children are more likely to have abnormally thick heart muscle ue when they become adults, which increases the risk of heart attack and heart failure.

Kids may require lots of food fuel to stoke their metabolism, but they still need to be active. An hour of moderate activity each day is recommended. Though some kids love to ride their bikes or play basketball, far too many prefer to plop down in front of the television after school and often, they don't budge til dinnertime. Parents may need to intervene to keep things moving. When kids find activities that they enjoy, they're more likely to stick with it and they'll do it more often.

Here are some tips to keep them moving:
1.Limit their hours of TV or computer games - if they want to watch/play beyond that, have them stand up! (This is especially helpful to kids with weight issues. Standing up burns more calories, and this may make them more inclined to go and do something active rather than standing to watch television)

2.Step it - set a good example and take the stairs when you're together (rather than elevators.)

3.Go for a family walk before or after dinner; in addition to exercise, it's a great way to spend more time together, sharing your news of the day.

4.If it's feasible, encourage them to walk or ride their bikes to and from school.

5.Spend less time at the movies and more time playing soccer or swimming.

6.Involve them in walking the dog, yardwork, housecleaning - anything that's active.

7.A small investment in basic equipment can make a big change. Help your children find a new activity they love: hula-hoop, mini-trampoline, jumprope, kickball, badminton, roller skates, basketball or swimming!

8.Set a good example and be an active parent -- eat healthy and exercise!

Read food nutrition labels closely

By R.J. Ignelzi
Copley News Service

Forget Oprah's latest book club selection. Never mind what's topping the New York Times best-seller list. The must-read for nearly everyone is thought-provoking, empowering and available on nearly every grocery store shelf.

It's the nutrition label on most food products.

While it's not as captivating as a Stephen King or John Grisham novel, reading and utilizing this material on a regular basis may make you and your family healthier.

WELL READ - Your health may depend on how closely you heed your food's nutritional labels. CNS Photo by Crissy Pascual.
"Reading a food label can guide you to better food selections," says Christine Zoumas, a registered dietitian and a senior nutrition researcher at the University of California San Diego Medical Center.

"There are certain nutrients you want to limit, like saturated fat and cholesterol, and other nutrients you want more of, like fiber. By reading the nutrition facts on the labels you can compare different products and make sure you're getting (the healthiest ones)."

PORTION SIZE TIPS - Other keyword: Serving, weight, health, fist, light bulb, mouse, baseball, thumb, dice

However, for many consumers, today's nutrition labels with the long lists of numbers, percentages and stock "nutri-speak" phrases only offer up a heaping helping of confusion. In order for food labels to help you achieve a more healthful diet, you need to be able to translate them into language and concepts that are meaningful to you. That doesn't mean you have to walk around the grocery store with a calculator and a dictionary. By simply zeroing in on a couple of label items and looking at how these fit into your daily diet, you'll get the biggest nutrition bang for your buck.

The first thing you should focus on is the serving size listed at the top of the nutrition facts box.

"Nothing else matters if you don't know what size serving you're talking about," Zoumas says. "In order to interpret all the nutrients and calorie information, you must look at the serving size."

To avoid misleading consumers into believing a food is low in fat or calories by unrealistically reducing the listed serving size (for example, a candy bar that's supposed to count as three servings), the U.S. Food and Drug Administration (FDA) has standardized most food serving sizes.

The agency says the serving sizes must be reasonable portions, in a weight or household measurement that's easy for people to understand, Zoumas explains.

However the listed serving size may not always reflect the portion size people actually consume.

"The (listed) serving size for most drinks is 8 ounces. But, most of us are looking at 16-ounce or 24-ounce drinks. The serving size for Oreos is two cookies. But, for many people, one serving is a lot more than that," says Patti Wooten Swanson, nutrition, family and consumer adviser for the University of California Cooperative Extension Service of San Diego County. "You have to take this into account when comparing the calories and other nutrients of different products. If one is larger or smaller than the other it can make a big difference (in nutritional values).

"In addition to noting the calories for a serving, it's important to check out the nutrients you want plenty of - fiber, calcium and vitamin C - and those you want to limit - saturated fat, trans fats, cholesterol and sodium.

Nobody expects you to memorize all the recommended daily allowances (RDAs) for each nutrient. Instead, check out how nutrient-rich or -poor a product is by reading the percent of daily values, listed as percentages next to each nutrient.

Based on a 2,000-calorie-a-day diet, the percent of daily values shows how much of a nutrient in one serving contributes to the recommended daily intake of that particular nutrient. So, for example, if you see that the amount of calcium in one serving of a food supplies 38 percent of your calcium needs for one day, you've got a winner. You're more than a third of the way to satisfying your bone-building calcium needs for the day.

However, if you see that a single serving contains 46 percent of the recommended intake of saturated fat, consider putting it back on the shelf. Saturated fat is one of the nutrients we need to limit in our diet, and getting half of the recommended daily amount in one serving is asking for trouble.

People with certain health conditions or concerns should pay close attention to those nutrients that may affect them. Diabetics should concentrate on the sugar and carbohydrate amounts. People with hypertension should focus on keeping the sodium low. Those with heart problems need to watch their saturated fat, trans fat and cholesterol grams. And women should look for products offering as much calcium and vitamin D (if listed) as possible.

In addition to offering long lists of numbers and percentages for the nutrient content of a product, food makers can also make nutritional claims. Often found on the front of the package in big, bold lettering, these claims aren't just random advertising hype to help attract shoppers. Regulated by the FDA and the U.S. Department of Agriculture, the claims have to be substantiated by the nutritional facts.

- Serving size: Pay attention to this and the number of servings in the package. The size of the serving on the food package influences all the nutrient amounts listed on the label.

- Calories: The number of calories this food contains for the stated serving size. (You have to burn 3,500 calories to lose one pound of body weight.)

- Percent of Daily Value: Shows how much one serving of a nutrient contributes to the total daily recommended intake of that nutrient for a 2,000-calorie a day diet.

- Total fat: Should make up no more than 20 percent to 35 percent of your total calories. Saturated fat and trans fats raise cholesterol and increase risk of heart disease and stroke. The American Heart Association recommends consuming less than 7 percent of total calories as saturated fat or trans-fat. Most fat should come from monounsaturated or polyunsaturated sources (fish, nuts, canola and olive oils).

- Cholesterol: Too much of it in your diet may lead to too much of it in your blood, which can lead to heart disease and stroke. Consume less than 300 milligrams per day. People with heart disease, high LDL (bad) cholesterol levels or who take cholesterol medication should consume less than 200 milligrams per day.

- Sodium: Healthy adults should consume less than 2,300 milligrams of sodium each day (about one teaspoon). African-Americans, older adults and people with high blood pressure should consume less than 1,500 milligrams per day.

- Total carbohydrates: This listing includes the healthy carbs (whole grains, fruits and vegetables) and the unhealthy or refined carbs (sugar). Try to keep the sugar grams low and load up on the fiber. Adults should eat 21 to 35 grams of fiber daily. Soluble fiber (oatmeal, barley, dried beans) can help lower cholesterol levels. Insoluble fiber (whole grains, fruit and vegetables) protects against bowel disorders and may help digestion.

- Protein: The government food safety advisory and regulation panels don't offer any daily value percentages for protein since getting enough of it has not been a problem in the American diet.

- Vitamins and minerals: Only two vitamins (A and C) and two minerals (calcium and iron) are required on the food label. Manufacturers can voluntarily list other vitamins and minerals in the food.

Merrie Monteagudo contributed to this story.

Avoiding protein overload

Yes, you can get too much protein. Several medical conditions make it difficult for people to digest and process proteins properly. As a result, waste products build up in different parts of the body. People with liver disease or kidney disease either don’t process protein efficiently into urea or don’t excrete it efficiently through urine. The result may be uric acid kidney stones or uremic poisoning (an excess amount of uric acid in the blood). The pain associated with gout (a form of arthritis that affects nine men for every one woman) is caused by uric acid crystals collecting in the spaces around joints. Doctors may recommend a low-protein diet as part of the treatment in these situations.

Boosting your protein intake: Special considerations

Anyone who’s building new tissue quickly needs extra protein. For example, the Dietary Reference Intake (DRI) for protein for women who are pregnant or nursing is 71 grams per day. Injuries also raise your protein requirements. An injured body releases above-normal amounts of protein-destroying hormones from the pituitary and adrenal glands. You need extra protein to protect existing tissues, and after severe blood loss, you need extra protein to make new hemoglobin for red blood cells. Cuts, burns, or surgical procedures mean that you need extra protein to make new skin and muscle cells. Fractures mean extra protein is needed to make new bone. The need for protein is so important when you’ve been badly injured that if you can’t take protein by mouth, you’ll be given an intravenous solution of amino acids with glucose (sugar) or emulsified fat.
Do athletes need more proteins than the rest of us? Recent research suggests that the answer may be yes, but athletes easily meet their requirements by increasing the amount of food in their normal diet.

Dodging protein deficiency

The first sign of protein deficiency is likely to be weak muscles — the body tissue most reliant on protein. For example, children who do not get enough protein have shrunken, weak muscles. They may also have thin hair, their skin may be covered with sores, and blood tests may show that the level of albumin in their blood is below normal. Albumin is a protein that helps maintain the body’s fluid balance, keeping a proper amount of liquid in and around body cells.
A protein deficiency may also show up in your blood. Red blood cells live for only 120 days. Protein is needed to produce new ones. People who do not get enough protein may become anemic, having fewer red blood cells than they need. Protein deficiency may also show up as fluid retention (the big belly on a starving child), hair loss, and muscle wasting caused by the body’s attempt to protect itself by digesting the proteins in its own muscle tissue. That’s why victims of starvation are, literally, skin and bones. Given the high protein content of a normal American diet (which generally provides far more protein than you actually require), protein deficiency is rare in the United States except as a consequence of eating disorders such as anorexia nervosa (refusal to eat) and bulimia (regurgitation after meals).

Monday, April 7, 2008

Calculating the Correct Amount of Protein You Need

As a general rule, the National Academy of Sciences says healthy people need to get 10 to 35 percent of their daily calories from protein. More specifically, the Academy has set a Dietary Reference Intake (DRI) of 45 grams protein per day for a healthy woman and 52 grams per day for a healthy man. (Check out Chapter 4 for a complete explanation of the DRI.)

These amounts are easily obtained from two to three 3-ounce servings of lean meat, fish, or poultry (21 grams each). Vegetarians can get their protein from 2 eggs (12–16 grams), 2 slices of prepacked fat-free cheese (10 grams), 4 slices of bread (3 grams each), and one cup of yogurt (10 grams). As you grow older, you synthesize new proteins less efficiently, so your muscle mass (protein tissue) diminishes while your fat content stays the same or rises.

This change is why some folks erroneously believe that muscle “turns to fat” in old age. Of course, you still use protein to build new tissue, including hair, skin, and nails, which continue to grow until you cross over into The Great Beyond. By the way, the idea that nails continue to grow after death — a staple of shock movies and horror comics — arises from the fact that after death, tissue around the nails shrinks, making a corpse’s nails simply look longer. Who else would let you in on these secrets?

The lowdown on gelatin and your fingernails

Everyone knows that gelatin is protein that strengthens fingernails. Too bad everyone’s wrong. Gelatin is produced by treating animal bones with acid, a process that destroys the essential amino acid tryptophan. Surprise:
Bananas are high in tryptophan. Slicing bananas onto your gelatin increases the quality of the protein. Adding milk makes it even better, but that still may not heal your splitting nails. The fastest way to a cure is a visit to the dermatologist, who can tell you whether the problem is an allergy to nail polish, too much time spent washing dishes, a medical problem such as a fungal infection, or just plain peeling nails. Then the dermatologist may prescribe a different nail polish (or none at all), protective gloves, a fungicide (a drug that wipes out fungi), or a lotion product that strengthens the natural glue that holds the layers of your nails together.

Complete proteins and incomplete proteins

Another way to describe the quality of proteins is to say that they’re either complete or incomplete. A complete protein is one that contains ample amounts of all essential amino acids; an incomplete protein does not. A protein low in one specific amino acid is called a limiting protein because it can build only as much tissue as the smallest amount of the necessary amino acid. You can improve the protein quality in a food containing incomplete/ limiting proteins by eating it along with one that contains sufficient amounts
of the limited amino acids. Matching foods to create complete proteins is called complementarity.

For example, rice is low in the essential amino acid lysine, and beans are low in the essential amino acid methionine. By eating rice with beans, you improve (or complete) the proteins in both. Another example is pasta and cheese. Pasta is low in the essential amino acids lysine and isoleucine; milk products have abundant amounts of these two amino acids. Shaking Parmesan cheese onto pasta creates a higher-quality protein dish. In each case, the foods have complementary amino acids. Other examples of complementary protein dishes are peanut butter with bread, and milk with cereal. Many such combinations are a natural and customary part of the diet in parts of the world where animal proteins are scarce or very expensive. Here are some categories of foods with incomplete proteins:
  • Grain foods: Barley, bread, bulgur wheat, cornmeal, kasha, and pancakes
  • Legumes: Black beans, black-eyed peas, fava beans, kidney beans, lima beans, lentils, peanut butter, peanuts, peas, split peas, and white beans
  • Nuts and seeds: Almonds, Brazil nuts, cashews, pecans, walnuts, pumpkin seeds, sesame seeds (tahini), and sunflower seeds In order for the foods to complement each other, you must eat them together. In other words, rice and beans at one meal, not rice for lunch and beans for dinner.

Tuesday, April 1, 2008

Homocysteine and your heart

Homocysteine is an intermediate, a chemical released when you metabolize (digest) protein. Unlike other amino acids, which are vital to your health, homocysteine can be hazardous to your heart, raising your risk of heart disease by attacking cells in the lining of your arteries by making them reproduce more quickly (the extra cells may block your coronary arteries) or by causing your blood to clot (ditto).
Years and years ago, before cholesterol moved to center stage, some smart heart researchers labeled homocysteine the major nutritional culprit in heart disease. Today, they’ve been vindicated. The American Heart Association cites high homocysteine levels as an independent probable (but not major) risk factor for heart disease, perhaps explaining why some people with low cholesterol have heart attacks. But wait! The good news is that information from several studies, including the Harvard/ Brigham and Women’s Hospital Nurses’ Health Study in Boston, suggest that a diet rich in the B vitamin folate lowers blood levels of homocysteine. Most fruits and vegetables have plentiful amounts of folate. Stocking up on them may protect your heart.

High-quality and low-quality proteins

Because an animal’s body is similar to yours, its proteins contain similar combinations of amino acids. That’s why nutritionists call proteins from foods of animal origin — meat, fish, poultry, eggs, and dairy products — high quality proteins. Your body absorbs these proteins more efficiently; they can be used without much waste to synthesize other proteins. The proteins from plants — grains, fruit, vegetables, legumes (beans), nuts, and seeds — often have limited amounts of some amino acids, which means their nutritional content is not as high as animal proteins.
The basic standard against which you measure the value of proteins in food is the egg. Nutrition scientists have arbitrarily given the egg a biological value of 100 percent, meaning that, gram for gram, it’s the food with the best supply of complete proteins. Other foods that have proportionately more protein may not be as valuable as the egg because they lack sufficient amounts of one or more essential amino acids.
For example, eggs are 11 percent protein, and dry beans are 22 percent protein. However, the proteins in beans don’t provide sufficient amounts of all the essential amino acids, so they (the beans) are not as nutritionally complete as proteins from animal foods. The prime exception is the soybean, a legume that’s packed with abundant amounts of all of the amino acids essential for adults. Soybeans are an excellent source of proteins for vegetarians, especially vegans, which are vegetarians who avoid all products of animal origin, including milk and eggs.
The term used to describe the value of the proteins in any one food is amino acid score. Because the egg contains all the essential amino acids, it scores 100.

Super soy: The special protein food

  • Nutrition fact No. 1: Food from animals has complete proteins.
  • Nutrition fact No. 2: Vegetables, fruits, and grains have incomplete proteins.
  • Nutrition fact No. 3: Nobody told the soybean.
Unlike other vegetables, including other beans, soybeans have complete proteins with sufficient amounts of all the amino acids essential to human health. In fact, food experts rank soy proteins on par with egg whites and casein (the protein in milk), the two proteins easiest for your body to absorb and use. Some nutritionists think soy proteins are even better than the proteins in eggs and milk, because the proteins in soy come with no cholesterol and very little of the saturated fat known to clog your arteries and raise your risk of heart attack.

Better yet, more than 20 recent studies suggest that adding soy foods to your diet can actually lower your cholesterol levels. One-half cup of cooked soybeans has 14 grams of protein; 4 ounces of tofu has 13. Either serving gives you approximately twice the protein you get from one large egg or one 8-ounce glass of skim milk, or two-thirds the protein in 3 ounces of lean ground beef. Eight ounces of fatfree soy milk has 7 milligrams protein — a mere 1 milligram less than a similar serving of skim milk — and no cholesterol. Soybeans are also jam-packed with dietary fiber, which helps move food through your digestive tract. In fact, soybeans are such a good source of food fiber that I feel obligated to add a cautionary note here. One day after I’d read through a bunch of studies about soy’s effect on cholesterol levels, I decided to lower my cholesterol level right away.

So I had a soy burger for lunch, a half cup of soybeans and no-fat cheese for an afternoon snack, and another half cup with tomato sauce at dinner. Delicacy prohibits me from explaining in detail how irritated and upset all that fiber made my digestive tract, but I’m sure you get the picture.
If you choose to use soybeans (or any other dry beans for that matter), take it slow — a little today, a little more tomorrow, and a little bit more the day after that.