Exploding Nutrition Myths

Exploding Nutrition Myths
Brenda Davis, RD/ 2004

1. The Atkins diet is best for weight loss.

    The Atkins diet is the king of low carbohydrate diets, and while these types of diets are nothing new, their popularity over the past 2 or 3 years has been mind-boggling.

    The Atkins diet allows about 5-10% of calories from carbohydrates - a stark contrast to the 55-75% of calories from carbohydrates recommended for maximum disease risk reduction by the World Health Organization.
Low-carb diets are based on the premise that carbohydrates make people fat, and are responsible for much of the chronic disease that plagues Western nations. If the low carb gurus were right, the highest rates of obesity and chronic degenerative disease in the world would occur in areas with the highest carbohydrate intakes. In fact, the exact opposite is true. The lowest rates of obesity and chronic disease occur in populations consuming 60-75% of calories as carbohydrates. The key to the healthfulness of these diets is in the source of the carbohydrates – whole, unrefined plant foods such as vegetables, legumes, grains, fruits, nuts and seeds.

    Carbohydrates are the sun’s way of storing energy in plants. All plant foods contain carbohydrates. When carbohydrates come from whole plant foods they are packaged with the most powerful protectors in the diet - fiber, phytochemicals, phytosterols, antioxidants, and healthful mono and polyunsaturated fats, including essential fatty acids. Unfortunately, the vast majority of carbohydrates that North Americans consume are refined. That means we remove almost everything of value to health prior to consuming them. Getting rid of refined carbohydrates is what Atkins gets right. Minimizing unrefined carbohydrates is what Atkins gets wrong. When all carbohydrates are minimized, fat and protein are automatically maximized. Fat accounts for about 50-66% of calories, and protein about 30% of calories on the Atkins diet. In the short term, many people on this type of diet end up with constipation, bad breath, headaches and irritability. In the long term, they may increase their risk for kidney and liver disease, heart disease, hypertension, osteoporosis, several forms of cancer, especially colorectal cancer, prostate and endometrial cancer, and a number of immune/inflammatory disorders. While there is little doubt that low carb diets can work for quick weight loss, we mortgage our health in the process. Remember, it is virtually impossible to enjoy optimal health when you put a lid on the most concentrated sources of protective dietary components, while loading up on the most concentrated sources of the most damaging dietary components.



2. You need meat to get enough protein.
    Many people believe that meat is our best source of protein, and that without meat children will not grow properly, and adults will sacrifice strength and agility. The meat myth is so pervasive in our society that it is hardly questioned.

    Protein is an essential nutrient, allowing our body systems to operate smoothly. It is necessary for building and repairing body cells, transporting oxygen and producing antibodies. A wide variety of proteins are constructed from a “pool” of amino acids distributed in the fluids throughout our bodies. Amino acids that cannot be made in our bodies are called indispensable amino acids (IAA). These amino acids must come from the food we eat. All IAA are manufactured by plants; animals cannot make them. Of course, people can get their IAA from animal products, but the IAA in animal products can all be traced back to their plant origins. Once in our cells, an amino acid molecule from a piece of chicken is no different than an amino acid molecule from a soybean.
How much protein do we need for good health? The exact amount depends on our age, body size, and, to some extent, on the composition of our diet. For most people, 0.8 g/kg body weight is recommended, assuming adequate energy intakes. Protein needs are higher during times of growth (pregnancy, lactation, infancy, childhood and adolescence), for some athletes (especially competitive athletes), and for people recovering from certain illnesses. Some experts suggest that recommended protein intakes should be increased 10-20 percent for vegetarians who consume primarily whole plant foods, in order to compensate for their lower digestibility. This increase is thought to be unnecessary for those who include soy products such as tofu and soymilk, or dairy products and eggs in their diets. This amount of protein is not difficult to get in any vegetarian or vegan diet containing a variety of plant foods. Even elite athletes can meet all of their protein needs without a drop of animal protein.


    In our society, many people think that eating large amounts of animal protein will lead to bigger muscles. Unfortunately, this is not the case. Eating excessive amounts of animal protein puts stress on the kidneys and liver, and can contribute to heart disease, stroke, colorectal cancer, and osteoporosis. Protein from meat comes packaged with saturated fat, cholesterol. By contrast, protein-rich plant foods are entirely free of cholesterol and animal protein, and most are low in saturated fat. As a bonus, they are brimming with protective phytochemicals, fiber, and trace minerals, such as magnesium, calcium and potassium (minerals that are lacking in meat).



3. You need milk to get enough calcium.
    The belief that it is practically impossible to get enough calcium without milk is deeply ingrained in our society. Children are taught that if they don’t drink milk, they won’t grow tall and have strong bones. Adults are quite convinced that osteoporosis is a dairy-deficiency disease.
In truth, humans have absolutely no requirement for cow’s milk. While this may seem like quite a radical statement, just stop and think about it. Each mammal produces milk that is uniquely designed to meet the nutritional needs of their offspring. It is meant to be their sole source of nutrition during the early weeks or months of life, giving them everything they need to grow and thrive. It defies rationality to think that any mammal would require the milk of another species for its survival. The milk of one species is never essential for the life of another; humans have no greater need for cow’s milk than for we do for moose milk.

    Yet somehow the powerful messages that have convinced us of milk’s supremacy in the calcium empire are not easily erased from our minds.  It comes as quite a revelation that prior to the advent of agriculture, humans in many parts of the world had dairy-free diets that provided an estimated 1500-3000 mg of calcium per day. This calcium came primarily from plants. Still today there are millions of people in the world, with varying calcium intakes, who consume little (if any) dairy products and have bone health as good, or better than populations with the greatest dairy intakes. The lesson here is that osteoporosis is not a dairy deficiency disease. It is not even a simple calcium deficiency disease. Bone health is a function of many things, including genetics, physical activity, hormone production, exposure to sunshine (vitamin D), and several dietary factors. Those who have great bone health may be genetically advantaged with bigger, stronger bones; they may be more physically active and have greater exposure to the sun. That is not to say that calcium intake is not important to bone health, because it is, but rather that it is only one of many factors important to lifelong bone health.

    We need an estimated 1000-1300 mg of calcium per day (adolescents 9-18 years – 1300 mg; adults 19-50 years – 1000 mg; adults 50+ years – 1200 mg). For most people, the easiest way to insure sufficient calcium without dairy is to use a combination of calcium-fortified foods and calcium-rich plant foods.  Select a variety of calcium-rich foods throughout the day. Including 6-8 servings of foods containing approximately 120-150 mg of calcium each would provide a total of approximately 720-1200 mg calcium.  An additional 100-300 mg of calcium will generally be provided by other plant foods containing smaller amounts of calcium.

Plant Calcium Sources (1 serving = 120-150 mg calcium)
½ cup fortified soymilk or other fortified non-dairy milk.
½ cup fortified juice
¼ cup calcium set tofu
¼ cup almonds or 3 Tbsp almond butter
1 cup cooked/2 cups raw calcium-rich greens (kale, broccoli, collards, Chinese greens, okra)
1 cup high calcium beans (soy, white, navy, Great Northern or black turtle), cooked
1 cup hummus
¼ cup hijiki seaweed
1 Tbsp. blackstrap molasses
5 figs



4. Soy products are damaging to health.
    For a while it appeared as though saint soy could do no wrong - reports suggested that it could reduce the risk of heart disease, certain cancers, osteoporosis, kidney disease, symptoms of menopause and possibly even baldness in men. Yet just when soy seemed to be on top of its empire, articles and websites began to appear accusing this new-found health hero of being a villain in disguise. Soy naysayers claimed that soy consumption was linked to thyroid problems, birth defects, reproductive problems, nutritional deficiencies, certain cancers and cognitive dysfunction. This left consumers wondering if soy is really a saint or a sinner.

    Let’s briefly consider a few of the major allegations against soy, and what science says thus far:


    Claim: Soy increases risk of breast cancer. There is little, if any, evidence suggesting that soy intake increases breast cancer risk in humans. Indeed, the evidence points slightly in the other direction. The most convincing data is for those eating soy from an early age (especially during puberty). It appears that in this sub-group, lifetime breast cancer risk may be significantly reduced. For those beginning to consume soy during adulthood, risk for breast cancer appears unaffected. For those who have estrogen positive breast cancer, the jury is still out. Most experts advise that soy not be used therapeutically in this population, although there is insufficient evidence to suggest that soy consumers need to eliminate it from their diet.


    Claim: soy contains goitrogens that interfere with thyroid function. It is true that soy contains goitrogens, as do many other foods such as cruciferous vegetables (cabbage, cauliflower, broccoli and Brussels sprouts), sweet potatoes, lima beans, flaxseeds and millet. However, these foods have been implicated in thyroid dysfunction only when iodine status is poor. Soy does not cause thyroid problems in healthy, well-nourished people who are not deficient in iodine. However, vegetarians who do not insure a reliable source of iodine could increase their risk of thyroid problems if they eat a lot of soy and/or other foods rich in goitrogens (the main sources of iodine in a mixed diet are iodized salt, dairy products and fish). The answer is not to avoid soy or cruciferous vegetables, but to get enough iodine.


    Claim: Soyfoods, especially tofu can cause mental deterioration and accelerate aging. The Honolulu Heart Study in Hawaii found that Japanese men who ate the most tofu in middle age had the greatest mental deterioration as seniors. This study is widely sited as proof that tofu causes a reduction in cognitive function. More recently, there have been at least 3 other studies that have suggested that soy provides significant beneficial effects to cognitive function. In addition populations with high soy intake, including people in Asia and Seventh-day Adventists experience lower rates of dementia than those populations who eat little if any soy. While epidemiological data does not prove that soy is protective, it does suggest that it is unlikely to be detrimental.


    Claim: soy contains several substances that inhibit the absorption of essential minerals. Critics of soy say that vegetarians who consume tofu and bean curd as a substitute for meat and dairy products risk severe mineral deficiencies. They point out that soy is rich in phytates, which inhibits the absorption of minerals such as iron, calcium and zinc, and trypsin inhibitors, which block protein absorption. While there is no question that soy is naturally high in phytates and trypsin inhibitors (as are many other whole foods), these substances are greatly reduced by cooking, and other food processing techniques. The absorption of protein from soyfoods is excellent, and quite comparable to that of animal products. The absorption of calcium from soy is only slightly less than it is for cow’s milk. By contrast, the absorption of iron and zinc is low (though possibly higher than previously believed), although this does not mean that soy will induce deficiencies of these minerals. It is important, however, that vegetarians include other good sources of these nutrients, such as legumes and seeds.


    Claim: soy causes male reproductive problems. There is some concern that the isoflavones in soy could adversely impact male reproduction, and male sexual development. Scientific studies looking at a wide range of reproductive measures have not supported these allegations. There have also been no observed widespread reproductive problems in populations where regular soy consumption is the norm.



5. Moderation is the key to a healthful diet.
    The theory goes something like this: if we consume moderate amounts of a wide variety of foods, our diet will be healthful. The message of moderation has been at the forefront of nutrition campaigns for decades. Popular slogans such as “there are no good foods and no bad foods,” or “all foods can fit into a healthy diet” are variations on the moderation theme. Moderation makes good sense. The theory works very well when the bulk of the diet consists of healthful foods and the occasional “treat” is thrown in, but when the lion’s share of the diet consists of nutritional washouts, the theory falls flat on its face.


    In North America, where an estimated 70 percent or more of all deaths are diet and lifestyle induced, and the vast majority of the population is overweight or obese, it makes little sense to spend precious nutrition education dollars on these sorts of feel-good messages. Why spend a dime convincing an overweight, chronic disease-laden population that whatever they wish to eat is just fine, so long as it is consumed in moderation? Unfortunately, the answer may have more to do with politics than nutrition. Major sponsors of large nutrition education campaigns have traditionally been manufacturers of the very products most heavily implicated in increasing obesity and disease rates – heavily processed foods, including fast foods, snack foods and soda pop, and animal products such as beef, pork, chicken and dairy.  These sponsoring organizations may be more comfortable with campaigns that promote “everything in moderation” than they would be with campaigns that promote and encourage the kinds of diet and lifestyle changes that could really make a difference in health. If nutrition educators really want to succeed in making healthy choices easy for people, it is that they acknowledge that there are good foods and there are bad foods. No matter how we serve them, deep fried pork rinds do not fit into a healthy diet.  Let’s put our money into nutrition education messages that people need to hear:

    a) Center your diet on whole plant foods. Eat more vegetables, especially green leafy vegetables, and beans. Eat a variety of fruits and whole grains. Include small amounts of nuts and seeds in the daily diet.

    b) Reduce intake of refined carbohydrates – both starches (mainly white flour-based products) and sugars.

    c) Avoid foods containing trans fatty acids – products with added hydrogenated or partially hydrogenated vegetable oils, and most deep-fried fast foods.

    d) Reduce intake of animal products, especially those that are high in fat and cholesterol.




6. Vegetarian diets are risky, especially for children.
    Twenty or thirty years ago, mainstream health organizations considered vegetarian diets risky and vegan diets downright dangerous, especially during pregnancy, infancy and childhood. Today, even the most conservative health organizations recognize the safety and adequacy of vegetarian and vegan diets. In 2003 the following official position on vegetarian diets was released:

“It is the position of the American Dietetic Association and Dietitians of Canada that appropriately planned vegetarian diets are healthful, nutritionally adequate, and provide health benefits in the prevention and treatment of certain diseases.” 

Where the more vulnerable stages of life are concerned, they add:

“Well-planned vegan and lacto-ovo vegetarian diets are appropriate for all stages of the life cycle, including during pregnancy and lactation.  Appropriately planned vegan and lacto-ovo vegetarian diets satisfy nutrient needs of infants, children, and adolescents and promote normal growth.  Vegetarian diets in childhood and adolescence can aid in the establishment of life long healthy eating patterns and can offer some important nutritional advantages.” 



    As it turns out, vegetarian children and adolescents have lower intakes of cholesterol, saturated fat and total fat, and higher intakes of fruits, vegetables and fiber than nonvegetarians. Reports also indicate that they are leaner and have lower serum cholesterol levels.
It is important to recognize, however, that as with omnivorous or lacto-ovo vegetarian diets, vegan diets can be both adequate and inadequate. Care must be taken to insure sufficient energy, vitamin B12, and vitamin D, especially in children of weaning age (1-3 years). Other nutrients that may require attention include protein, essential fatty acids, iron, zinc, and riboflavin. Fortunately, the primary nutrition challenges for vegans are relatively easy to overcome. In fact, many of the nutrients of concern are now being added to foods commonly consumed by vegetarians (i.e. calcium, riboflavin, vitamins B12, and D to soymilk, and iron, zinc and vitamin B12 to meat substitutes).

    One of the best things about a vegetarian lifestyle is the advantages that we enjoy beyond ourselves. Being vegetarian is among the most powerful steps anyone can take towards the preservation of this planet. It takes only 5 percent of the resources to feed a vegan that it takes to feed a nonvegetarian. Being vegetarian is also an act of compassion towards our fellow beings. Every year in North America we slaughter about 10 billion animals for food. Over 90 percent of them are raised in factory farming conditions which are inhumane. Not purchasing animal products is a strong vote against this kind of cruelty.



For more information, check out these books by Brenda Davis, RD
The New Becoming Vegetarian (Vesanto Melina and Brenda Davis)
Becoming Vegan (Brenda Davis and Vesanto Melina)
Dairy-free and Delicious (Brenda Davis, Bryanna Clark Grogan and Jo Stepaniak)
Defeating Diabetes (Brenda Davis, Thomas Barnard and Barbara Bloomfield)