Value and Danger of Various Food Components

The Best Alternative Medicine
by Kenneth R. Pelletier

(Page 2 of 5)

Fiber. Eating a plant-based diet provides high levels of fiber. Water-soluble fibers, such as gums and pectins, protect against heart disease and diabetes by binding in the gut with bile acids, which contain cholesterol, thus preventing the reabsorption of these bile acids. Water-soluble fibers also delay glucose absorption and gastric emptying, which stabilizes blood sugar levels. Water-insoluble fibers, celluloses and hemicelluloses, protect against colon cancer by absorbing water, increasing stool volume, and speeding the passage of stool through the bowel. They also dilute the concentration of toxic bile acids, which can contribute to cancer. Presently, Americans consume an average of ten to fifteen grams of fiber per day, but should eat about twenty-five to thirty-five grams.

Recently, some nutrition experts expressed concern that high fiber consumption might inhibit the absorption and availability of minerals such as calcium, zinc, and iron. However, population studies disproved this.

Antioxidants. Our bodies are constantly exposed to "free radicals," or highly reactive molecules that can damage the body and are associated with degenerative diseases.

Fruits and vegetables are rich in substances known as phytochemicals, some of which act as antioxidants, protecting us against free radicals. Many phytochemicals in our foods have not yet been identified. This is a powerful argument for the use of whole foods rather than supplements. Another argument for this is that fruits and vegetables absorb more free radicals than isolated free-radical-scavenging vitamins, such as C and E. For example, ¾ cup of cooked kale can neutralize as many free radicals as 500 mg of vitamin C, or 800 IU of vitamin E, even though kale contains only 40 mg of vitamin C and less than 10 IU of vitamin E.

Other important phytochemicals occur in rice, tea, and spices. Cruciferous vegetables, including cabbage, broccoli, cauliflower, and Brussels sprouts, contain phytochemicals that seem to be protective against cancer. Some phytochemicals also appear to be helpful for minor illnesses, such as colds.

Fats. Government guidelines say that we should consume no more than 30 percent of total daily calories as fat. Actually, optimal fat intake may be much lower, perhaps 15 to 20 percent, or even less. To reverse coronary heart disease, Dr. Dean Ornish cuts fat to a mere 10 percent of total calories, and cholesterol to 5 mg. Most recently, concern has been raised from research that such an extremely low-fat diet may increase triglycerides and lower HDL, which would actually have the effect of increasing heart disease risk for some individuals. This contrasts with the American Heart Association's recommendation of 30 percent of total calories as fat and 300 mg of cholesterol.

Besides increasing the risk of cardiovascular disease, a high-fat diet also increases the risk of cancer, obesity, and diverticulitis, which is an inflammation of the colon due to pockets of stagnant digested matter.

There are three kinds of dietary fats: saturated, polyunsaturated, and monounsaturated.

Saturated fats are primarily found in animal foods and in tropical oils, such as coconut and palm oil, which are solid at room temperature. These fats can be the most harmful, because they easily clog arteries.

Polyunsaturated fats are found in safflower, sunflower, corn, and fish oils. They contain both omega-6 and omega-3 essential fatty acids (EFAs). Theoretically, humans evolved on a diet that consisted of small and approximately equal amounts of omega-6 and omega-3 fatty acids, but now most people eat about twenty times more omega-6 than omega-3.

Omega-6 is useful in repairing injuries and causing blood to clot and blood vessels to constrict. Omega-3, however, inhibits blood clotting, relaxes smooth muscles in blood vessel walls, and protects against heart arrythmias, thereby reducing the risk of heart disease. Many foods are rich in omega-3 EFAs, including cold-water fish, such as salmon and mackerel, and flax and flaxseed oil. Smaller amounts of omega-3 fatty acids are contained in great northern, navy, kidney, and soybeans. Among oils, flaxseed oil and canola oil are high in omega-3 EFAs, and so are soy, pumpkin seed, evening primrose, borage seed, walnut, and black currant oils. Actually, the best source of omega-3 fatty acids is flaxseed oil. It contains 50 percent omega-3, compared to the 10 percent found in canola oil.

With the discovery of the relationship between cholesterol and heart disease, Americans were encouraged to switch from animal fats, such as butter, to polyunsaturated fats, including the oils we just discussed. Unfortunately, this solution presented another set of problems. When these oils undergo metabolism, they are highly susceptible to lipid peroxidation, or rancidity, which gives rise to harmful free radicals. Most researchers now believe that it is better to use monounsaturated fats, which not only reduce the risk of lipid peroxidation but also reduce LDL, or bad cholesterol, while maintaining high levels of HDL, or good cholesterol. Olive oil and canola oil are high in monounsaturated fats.

Margarine is a polyunsaturated oil that has undergone hydrogenation to make it solid at room temperature. However, hydrogenation creates man-made molecules called trans-fatty acids, which may interfere with metabolic functions. Thus, in the rush away from butter, many people may have ended up compromising their health.

Nonetheless, very recently, some researchers concluded that monounsaturated fats may not be any better than polyunsaturated fats, because monounsaturated fats may be only slightly less susceptible to oxidation than polyunsaturated fats.

Therefore, when all these complexities are weighed and sorted, the bottom-line recommendation: Cut back on all forms of fats, except omega-3!

Dairy Products. Nonfat milk is an excellent source of calcium, but dairy products may be harmful to many people. It may not even be natural for our species to consume dairy products, since the consumption of cow's milk is a relatively recent phenomenon among humans. Milk protein allergy occurs frequently among young children, and lactose intolerance is widespread throughout the world.

Milk sugar is broken down into two simple sugars, glucose and galactose. Galactose may not be easily metabolized, and may accumulate in certain tissues; this may contribute to cataracts. Whole-milk dairy products also carry the risk of contamination with fat-soluble pesticides, sulfa drugs, and antibiotics. Nonfat dairy products do not carry these contaminants.

Calcium can also be obtained from plant sources, including dark green, leafy vegetables, many beans, almonds, and some dried fruits.

People who do want to consume dairy products should use only skim or 1 percent milk and dairy products. Children under the age of two should consume whole milk, if they use cow's milk, although soy milk is an excellent alternative. For infants, breast milk is the wisest choice. Milk substitutes, such as soy, almond, rice, or goat's milk, are an option for anyone wanting to avoid dairy products. Goat's milk is metabolized differently from cow's milk and may be a useful substitute for individuals with lactose intolerance to cow's milk.

Protein. Proteins play many important roles in the body, helping in the repair and maintenance of tissues. Plant proteins lower cholesterol and may improve the function of arteries. Proteins also make up hormones, enzymes, and neurotransmitters.

However, most Americans appear to eat too much protein. Protein cannot be stored in the body, so protein that is not used for body maintenance is converted to carbohydrate. During the process, the nitrogen-containing molecules that are left are processed by the liver into urea, which is excreted by the kidneys. Therefore, too much protein in the diet may overwork the kidneys and lead to sclerosis and reduced kidney function. High levels of protein in the diet also cause the body to lose calcium by increasing calcium excretion in the urine. Animal protein causes more calcium loss than vegetable protein.

Americans, on average, consume approximately twice the government's recommended level of protein. Even athletes do not need protein in excess of the RDA, which is 51 grams per 150 pounds of body weight. There is no evidence that protein supplements or high-protein foods are helpful in athletic training, and the old idea of the high-protein training diet has been discarded by most experts.

Recent evidence has shown that vegetarians do not need to engage in complex "protein combining" in order to receive complete protein, containing all of protein's amino acid "building blocks." This practice sometimes results in excessive protein intake.

If your diet contains animal products, it is likely that your protein intake already exceeds the RDA. Since excess protein in general, and particularly excessive animal protein, is associated with increased risk of bone loss, atherosclerosis, kidney stone formation, and impaired kidney function, it is a good idea to reduce or eliminate animal foods from the diet.

Copyright © 2000 by Dr. Kenneth R. Pelletier, Inc.

About the Author

Dr. Kenneth R. Pelletier is a clinical professor of medicine at the University of Maryland and the University of Arizona Schools of Medicine. He is a medical and business advisor to NIH, the World Health Organization (WHO), and major corporations, including American Airlines, Medtronic, Disney, Merck, Ford, Microsoft, Blue Cross, Blue Shield, and United Healthcare. As director of the American Health Association, he is the author of more than two hundred professional papers, and he was previously a clinical professor of medicine at the Stanford University School of Medicine.