The Vegetarian Resource Group
PO Box 1463
Baltimore, MD 21203
Co-Executive Secretary of the Dietary Guidelines Advisory Committee
Center for Nutrition Policy and Promotion
U.S. Department of Agriculture
3101 Park Center Drive, Room 1034
Alexandria, VA 22302
July 13, 2010
Comments submitted electronically at www.dietaryguidelines.gov
Dear Ms. Davis:
The Vegetarian Resource Group is a nonprofit educational organization that works with individuals, consumer groups, food companies, professional associations, government agencies, academic institutions, and other relevant constituencies to disseminate accurate information and sound advice to the public concerning vegetarian diets.
We were extremely impressed with the thoroughness of the recent Report of the Dietary Guidelines Advisory Committee on the Dietary Guidelines for Americans, 2010. The report makes a clear and compelling case for a rapid shift in the American diet to one that is more plant-based. The evidence-based approach used throughout the report allows readers to understand the basis for the recommendations that are made. This is an impressive report and we commend and thank the committee members for their diligence.
In an earlier letter we stated, “As advocates for people who choose to follow a vegetarian diet, we believe that the Dietary Guidelines should include information about vegetarian diets. This has been done somewhat in the past with suggestions for alternatives to meat products but information is limited. “We were quite pleased to see that this report contains a much more extensive discussion of vegetarian diets than previous reports.
We hope the following suggestions will be considered when finalizing the report.
1. Decrease or eliminate emphasis on combining plant proteins.
The need to combine plant proteins is repeatedly stressed throughout the report. For example, the Executive Summary states, “Plant proteins can be combined to form complete proteins if combinations of legumes and grains are consumed. Plant-based diets are able to meet protein requirements for essential amino acids through planning and offer other potential benefits, such as sources of fiber and nutrients important in a health-promoting diet.” Part D, Section 4, Protein states, “Individuals who restrict their diet to plant foods may be at risk of not getting adequate amounts of certain indispensable amino acids because the concentration of lysine, sulfur amino acids, and threonine are sometimes lower in plant than in animal food proteins. … Vegetarian diets that include complementary mixtures of plant proteins can provide the same quality of protein as that from animal protein. Education is needed for those designing diets containing complementary proteins for consumers switching to a more plant-based diet.”
While protein combining may be necessary in situations of extremely limited food choices, there is no evidence of protein or amino acid deficiencies in those eating plant-based, vegetarian, or vegan diets in countries where a variety of foods are readily available. A classic review of plant proteins supports the lack of evidence for combining proteins, even on a daily basis and says, “Although protein and amino acid requirements are conventionally expressed as daily rates (of intake) there is no implication that these amounts must be consumed each and every day. Therefore, it is not essential, at least in adults, that daily intakes of protein, or presumably of each indispensable amino acid, must equal or exceed the physiological requirement; it is apparently sufficient for the average intake over a number of days to achieve this level.” Our concern is that over-emphasis of this concept or of the need to carefully plan a plant-based diet will lead people to avoid potentially health-promoting plant-based, lacto-ovo vegetarian, and vegan diets. Even without stressing the concept of protein combination, the food patterns that accompany this report ensure that a variety of protein sources will be eaten. For example, the vegan food pattern includes grains, beans and peas, soy products, nuts and seeds, and (non-dairy) milk.
Additionally, there is no evidence of deficiencies of lysine, sulfur amino acids, and threonine in those who restrict their diet to plant foods.
2. Clarify information on plant-calcium sources and on the risk of fractures associated with vegan diets.
The report describes vegetable sources of calcium as being of limited bioavailability. For example, Part D, Section 2, Nutrient Adequacy states, “In addition, many vegetables contain calcium, another nutrient of concern; although the bioavailability of calcium in these foods is limited.” and “Some plant foods contribute calcium that is well absorbed, but the large quantity of these plant foods that would be needed to provide the equivalent amount of calcium found in 8 ounces of fluid milk may be unachievable for many.”
A number of dark green leafy vegetables contain significant amounts of bioavailable calcium. The research on this topic has been summarized in a review article by Weaver and Plawecki. Along with calcium that is better absorbed than calcium from dairy products, vegetables such as kale, turnip greens, broccoli, and Brussels sprouts also supply vitamin C, iron, potassium, vitamin A, and other key nutrients. As the report states, “calcium naturally occurring in foods is the recommended source.” Consideration should be given to increasing recommendations for these vegetables, especially as a source of calcium. Weaver and Plawecki’s review indicates that approximately 1 cup of turnip greens or 1.5 cups of Chinese cabbage or mustard greens would provide calcium equivalent to that found in 8 ounces of fluid milk. This certainly sounds possible for many to achieve, as a replacement for 1 or 2 cups of milk or milk equivalents.
The report states, “Vegan diets may increase risk of osteoporotic fractures.” Evidence is limited to support this statement. The EPIC study in the U.K. did find a higher rate of fractures in vegans but the difference in rates disappeared when the analysis was restricted to subjects who consumed at least 525 mg/day of calcium. This suggests it is total calcium intake rather than a vegan diet that affects fracture risk.
3. Provide specific information about foods to avoid/eat less.
We find recommendations such as the following to clearly indicate which foods should be emphasized: “2. Shift food intake patterns to a more plant-based diet that emphasizes vegetables, cooked dry beans and peas, fruits, whole grains, nuts, and seeds.” In contrast, the following type of statement does not provide specific guidance as to which foods should be avoided or limited: “Significantly reduce intake of foods containing added sugars and solid fats because these dietary components contribute excess calories and few, if any, nutrients”. Major sources of solid fats have been identified as cakes, cookies, pies, doughnuts, granola bars, regular cheese, sausage, franks, bacon, ribs, pizza, fried white potatoes, and dairy-based desserts, such as ice cream. A clear statement that these foods should be modified (for example cheeseless and meatless pizza, baked fries, sorbet) or limited would add clarity to the recommendations. We are surprised that a marked reduction in processed meat intake is not strongly and specifically recommended based on the reported findings of a 42% higher risk of CHD and 19% higher risk of type 2 diabetes associated with processed meat as well as the possible relation between processed meat and colorectal and prostate cancers (as discussed in Part D, Section 4, Protein).
4. Reconsider the use of 3 cups milk-equivalents per day.
Although Appendix E-3.6 compares meal plans containing 3 cups of milk-equivalents to those containing 0 cups of milk-equivalents, we do not, see a comparison of meal plans with 1 or 2 cups of milk-equivalents and with appropriate increases in servings of alternative sources of key nutrients (e.g. calcium, vitamin D, potassium) such as dark green leafy vegetables, fortified foods, dried beans, and soy products. Many Americans do not use 3 cups of milk-equivalents daily; it seems more realistic to promote alternative sources of key nutrients. Additionally, no consideration has been given to the environmental impact of the substantial increase in dairy product production that would be needed to meet these recommendations.
5. Recommend expanded vegetarian and vegan choices in the School Meals Program.
The report clearly identifies a need to “Improve foods sold and served in schools, including school breakfast, lunch, and after-school meals and competitive foods so that they meet the recommendations of the IOM report on school meals (IOM, 2009) and the key findings of the 2010 DGAC. This includes all age groups of children, from preschool through high school.” The sections of this report supporting the health benefits and nutrient adequacy of vegetarian diets clearly indicate the need for increased provision of vegetarian and vegan options in school meals. We suggest that a recommendation be included in this report supporting expanded vegetarian and vegan choices in school meals.
We applaud the Committee’s decision to include specific recommendations for future research and are hopeful that funding will be available for studies on plant compared to marine n-3 fatty acids; the development of better methods of conducting cohort studies of populations consuming plant-based diets compared to animal based diets, including defined classifications of vegetarian and “near vegetarian” eating patterns and more specific impacts of dried beans and peas on health; key nutrients in plant-based diets including calcium, iron, vitamin B12, and protein quality, especially in children and the elderly; and development of better assessment tools to classify vegetarian patterns in epidemiologic studies. Research in these areas would be of significant benefit to those consuming plant-based, vegetarian, and vegan diets. We especially support the allocation of funds for studies of food intakes of vegetarians and vegans so that separate patterns can be developed based on actual proportionate consumption of plant foods in all groups.
We appreciate the committee’s work on Dietary Guidelines 2010 and its solicitation of these public comments.
Reed Mangels, PhD, RD, LD, FADA
Nutrition Advisor, The Vegetarian Resource Group
Co-Director, The Vegetarian Resource Group
Co-Director, The Vegetarian Resource Group
1. Young VR, Pellett PL. Plant proteins in relation to human protein and amino acid nutrition. Am J Clin Nutr. 1994;59:1203S-12S.
2. Weaver CM, Plawecki KL. Dietary calcium: adequacy of a vegetarian diet. Am J Clin Nutr. 1994;59(suppl):1238S-1241S.
3. Appleby P, Roddam A, Allen N, Key T. Comparative fracture risk in vegetarians and nonvegetarians in EPIC-Oxford. Eur J Clin Nutr. 2007;61:1400-1406.
4. Micha R, Wallace SK, Mozaffarian D. Red and processed meat consumption and risk of incident coronary heart disease, stroke, and diabetes mellitus: A systematic review and meta-analysis. Circulation. 2010;121:2271-83.