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Food Guide Pyramid Revisions Letter
September 10, 2002
John Webster Director, Public Information and Governmental Affairs
Center for Nutrition Policy and Promotion
United States Department of Agriculture
3101 Park Center Drive, Room 1034
Alexandria, VA 22302
Dear Mr. Webster:
Thank you very much for inviting us to comment on the reassessment of the Food Guide Pyramid and for counting the Physicians Committee for Responsible Medicine (PCRM) among your stakeholders. We appreciate the opportunity to provide input into this important process. PCRM is a nonprofit organization that promotes preventive medicine, conducts clinical research, and encourages higher standards for ethics and effectiveness in research. We represent a broad base of doctors, dietitians, and other health professionals, as well as laypeople interested in nutrition and research issues.
As stated in the notes from the January 10, 2001, The Food Guide Pyramid: Moving into the 21st Century meeting, every decision regarding the revised Food Guide Pyramid should be soundly based on science. We certainly agree with this mandate, as well as with the proposal that the nutrition graphic should provide people with more than just the basic information needed to prevent nutrient deficiencies—this food guide should also support behavioral change. In addition, the graphic should promote an eating pattern that reduces chronic disease risk. Many Americans are overweight and are at a great risk for developing heart disease, cancer, and diabetes. On the basis of these criteria, we recommend three key revisions to the Food Guide Pyramid. We would like to see changes made in the Milk, Yogurt, and Cheese Group; the Meat, Poultry, Fish, Dry Beans, Eggs, and Nuts Group; and the Breads, Cereal, Rice, and Pasta Group.
The Milk, Yogurt, and Cheese Group
Scientific evidence no longer supports a broad-based recommendation to consume dairy products. Therefore, the Milk, Yogurt, and Cheese Group should be excluded in the revised Food Guide Pyramid. No other food group in the pyramid is focused on a specific nutrient (in this case, calcium), and all essential nutrients found in dairy products are also found in many non-dairy sources. Partly because of fortification, calcium can now be found throughout all food groups. For example, calcium is found in fortified cereals, juices, and non-dairy milk alternatives. It is also naturally present in some fruits, grains, nuts, vegetables, and beans.
More importantly, dairy product consumption and calcium intake has been linked to an increased risk of prostate cancer. Prostate cancer is the fourth most common malignancy among men worldwide, with an estimated 400,000 new cases diagnosed annually, accounting for 3.9 percent of all new cancer cases.1 Epidemiologic evidence strongly suggests that dietary factors play a major role in prostate cancer progression and mortality, with protective effects associated with consumption of fruit (particularly tomatoes), vitamin E, and selenium, and increased risk linked to dairy products, meat, and fat.2 Dairy product consumption has been associated with prostate cancer risk in divergent populations, and several studies have investigated mechanisms that may explain these findings.
Five of eleven cohort studies on dairy’s effect on prostate cancer have found significant associations between milk or dairy product consumption and prostate cancer incidence or mortality,3–7 while six studies found no association between milk or dairy product use generally and prostate cancer incidence or mortality.8–13 For example, in the Health Professionals Follow-Up Study, a cohort of U.S. male dentists, optometrists, osteopaths, pharmacists, and veterinarians, the relative risk of advanced prostate cancer associated with daily consumption of more than two glasses of milk, compared to zero, was 1.6 (95% CI, 1.2-2.1, Ptrend = 0.002). For metastatic disease, relative risk was 1.8 (95% CI, 1.2-2.8, Ptrend = 0.01). Of the milk consumed, 83 percent was skim or low-fat.5 In the Physicians’ Health Study cohort, consumption of two and one-half dairy servings daily was associated with increased risk of prostate cancer, compared to having less than one-half serving daily (RR 1.34, 95% CI: 1.04,1.71), after adjustment for age, smoking, exercise level, and body mass index (BMI).7
Also, new research casts grave doubt on the long-standing but poorly supported notion that dairy product consumption protects against bone loss. In countries where dairy products are not generally consumed, osteoporosis is less prevalent than in the United States. Studies have shown little effect of dairy products on osteoporosis.14 The Harvard Nurses’ Health Study followed 78,000 women for a 12-year period and found that milk did not protect against bone fractures. Indeed, those who got the most calcium from dairy sources had more fractures than those who rarely drank milk.15 In one of the most comprehensive reviews on the effect of dairy products on bone health, Weinseir and Krumdieck examined 57 research studies. In this review, 53 percent of the studies found results that were not significant, 42 percent found favorable results, and 5 percent found unfavorable results. The researchers concluded that there was not enough evidence to recommend dairy consumption for bone health to males, members of minority groups, or women over 30.16
In contrast to the lack of evidence for dairy products, two suggestions from the January 10, 2001, meeting—i.e., highlighting physical activity and making fruits and vegetables the base of the Pyramid—may, if implemented, contribute much to the prevention of osteoporosis. A recent study published in Pediatrics found that inactive teens had lower bone density by age 18 than those who engaged in regular physical activity. The researchers also found that the amount of calcium consumed (from milk or from other sources) had no effect on their bone density.17 Fruit and vegetable intakes also have a positive effect on bone health. A study published in the American Journal of Clinical Nutrition shows that higher intakes of fruits and vegetables throughout the teen years improve bone density in adulthood.18
Meat, Poultry, Fish, Dry Beans, Eggs, and Nuts Group
Our second recommendation for the reassessment of the Food Guide Pyramid is that the title of the protein-rich foods group (the Meat, Poultry, Fish, Dry Beans, Eggs, and Nuts Group) be reordered to highlight plant sources of protein. Beans and nuts should be placed first in the list and take central positions in the accompanying illustrations. For simplicity, we recommend that this group be named the Beans, Nuts, Eggs, and Meat Group. With heart disease being the number-one killer in America, the USDA is in an important position to promote healthier, cholesterol-free protein sources. Every 100 mg of cholesterol in the daily diet adds roughly 5 points to a person’s cholesterol level, although this varies from person to person. In practical terms, 100 mg of cholesterol is contained in four ounces of beef or chicken, half an egg, or three cups of whole milk. Highlighting white meat over red will not be beneficial, since beef and chicken have the same amount of cholesterol, 25 mg per ounce. Unlike fat, cholesterol is located mainly in the lean portion of meat, so emphasizing “leaner” cuts of meat in nutrition guides does little to reduce cholesterol intake.
Emphasizing plant protein sources in the new food guide could have tremendous effects on the average cholesterol level in the United States. For example, one study showed that people who adopted a vegetarian diet reduced their saturated fat intake by 26 percent and achieved a significant drop in cholesterol levels in just six weeks.19 Besides the low levels of saturated fat and absence of cholesterol in plant protein sources, vegetable protein also helps decrease the risk for heart disease. Studies have shown that replacing animal protein, such as casein, with soy protein reduces blood cholesterol levels even when the total amount of fat and saturated fat in the diet remains the same.20–21
While the elimination of meat protein has health-promoting attributes, the inclusion of beans and nuts in the diet also has important health benefits. For example, research from the Physicians’ Health Study at Harvard has found that nut consumption is associated with a decrease in risk of total coronary heart disease death, particularly sudden cardiac death.22 A reduction in the risk of coronary heart disease is also seen with legume consumption as reported in the NHANES I Epidemiologic Follow-up Study.23
Diets heavy in animal protein versus plant protein can cause an increase in bone loss, which can lead to osteoporosis, and an increase in kidney stone formation. Animal protein tends to leach calcium from the bones, leading to its excretion in the urine. International comparisons show a strong positive relationship between animal protein intake and fracture rates. These findings are supported by clinical studies showing that high protein intakes aggravate calcium losses. A 1994 report in the American Journal of Clinical Nutrition showed that when animal proteins were eliminated from the diet, calcium losses were cut in half.24 Another recent research study found that subjects consuming a diet high in animal protein for as little as six weeks had a significant decrease in estimated calcium balance.25
Also, the American Academy of Family Physicians notes that high animal protein intake is largely responsible for the high prevalence of kidney stones in the United States and other developed countries and recommends protein restriction for the prevention of recurrent nephrolithiasis.26 In part, this is because protein ingestion increases renal acid secretion, calcium resorption from bone, and a reduction in renal calcium resorption. In addition, animal protein is a major dietary source of purines, the major precursors of uric acid and an important factor in some stone formers. When uric acid builds up, especially in an acid environment, it can precipitate uric acid stone formers and decrease the solubility of calcium oxalate, a problem for calcium stone formers.26 Studies have shown that consumption of beans, particularly soybeans, have been associated with both cardiovascular and renal benefits.27
Reordering this protein group discourages the consumption of foods that have been linked to colon cancer and encourage foods that have been associated with a reduction in colon cancer risk. Colorectal cancer is one of the most common forms of cancer and is among the leading causes of cancer-related mortality. Long-term high intake of meat, particularly red meat, is associated with significantly increased risk of colorectal cancer. The 1997 report of the World Cancer Research Fund and American Institute for Cancer Research, Food, Nutrition, and the Prevention of Cancer, reported that, based on available evidence, diets high in red meat were considered probable contributors to colorectal cancer risk. Proposed mechanisms for the observed association include the effect of dietary fat on bile acid secretion, the action of cholesterol metabolites within the colonic lumen, and the carcinogenic action of heterocyclic amines produced during the cooking process, among others. In addition, diets high in animal protein are typically low in dietary fiber. Fiber facilitates the movement of wastes, including intralumenal carcinogens, out of the digestive tract, and promotes a biochemical environment within the colon that appears to be protective against cancer.28
Breads, Cereal, Rice, and Pasta
We also recommend that the Breads, Cereal, Rice, and Pasta Group be re-named in order to highlight healthier, whole-grain foods. The current group title also only highlights a few grains, most of which are consumed in their refined state (i.e., white bread, refined cereals, white rice, and white pasta). Instead, a variety of whole-grain foods should be emphasized, such as brown rice, whole-wheat bread, barley, oats, quinoa, and millet. For simplicity, this group could be re-named the Whole-Grain Foods Group.
Whole-grain foods should be emphasized over refined grain sources because they can be an important source of fiber in the diet. Currently, people in the United States are only eating between 12 and 15 grams of fiber a day, far less than the Daily Value of 25 grams.29 An easy way to boost fiber intake is to switch from refined grains to whole-grain foods. People who consume more whole grains are at lower risk of developing coronary heart disease, stroke, cancer, and diabetes,30 and women who consume more whole grains than refined grains have a lower mortality rate than women who favor refined grains.31 Inversely, consumption of refined grains has been associated with a higher risk of heart disease32 and with some forms of cancer.33
Overall, the USDA should recommend an optimal diet to Americans—one that not only meets basic nutrient requirements for most age and gender groups, but that also prevents the chronic diseases that plague so many people. Encouraging a higher nutrition standard will aid them in making healthier choices. A diet that emphasizes plant choices over animal products and whole grains over refined grains has been repeatedly shown in scientific literature to provide the most disease-fighting protection of any dietary pattern. It is time to translate this scientific research into a healthy food guide.
Thank you again for allowing us the opportunity to provide you with this information. Please feel free to contact us if you have any questions.
Brie Turner-McGrievy, M.S., R.D.
Clinical Research Coordinator
Amy Lanou, Ph.D.
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