Position of the American Dietetic Association: vegetarian diets

Effectiveness of a low-fat vegetarian diet in altering serum lipids in healthy premenopausal women

Few controlled trials have studied cholesterol-lowering diets in premenopausal women. None has examined the cholesterol-lowering effect of a low-fat vegetarian diet, which, in other population groups, leads to marked reductions in serum cholesterol concentrations and, in combination with other life-style changes, a regression of atherosclerosis. We tested the hypothesis that a low-fat, vegetarian diet significantly reduces serum total and low-density lipoprotein (LDL) cholesterol concentrations in premenopausal women. In a crossover design, 35 women, aged 22 to 48, followed a low-fat vegetarian diet deriving approximately 10% of energy from fat for 2 menstrual cycles. For 2 additional cycles, they followed their customary diet while also taking a "supplement" (placebo) pill. Serum lipid concentrations were assessed at baseline and during each intervention phase. Mean serum LDL, high-density lipoprotein (HDL), and total cholesterol concentrations decreased 16. 9%, 16.5%, and 13.2%, respectively, from baseline to the intervention diet phase (p<0.001), whereas mean serum triacylglycerol concentration increased 18.7% (p<0.01). LDL/HDL ratio remained unchanged. Thus, in healthy premenopausal women, a low-fat vegetarian diet led to rapid and sizable reductions in serum total, LDL, and HDL cholesterol concentrations.

Zinc intake and status in Australian vegetarians

Vegetarians have a lower incidence of many chronic diseases than omnivores. However, vegetarian diets could potentially result in lower intakes of some minerals, particularly Zn. In a cross-sectional study, dietary Zn intake was measured using 12 d weighed records in ninety-nine vegetarians (ten vegans) aged 18-50 years and forty-nine age- and sex-matched omnivores. In men, the mean daily Zn intake and Zn density values were similar in omnivores, ovolactovegetarians and vegans, but in women they were significantly lower in vegetarians (mean intake 6.8 mg v. 8.4 mg in omnivores) and few achieved the recommended intake. Significantly more vegetarian than omnivorous women had a daily Zn intake < 6 mg (44% v. 13%). Mean serum Zn concentrations were similar in female omnivores and vegetarians, despite the differences in intake. However, omnivorous men had a lower mean serum Zn concentration (0.85 microgram/ml v. 0.95 microgram/ml) and more subjects had levels below the reference range of 0.72-1.44 micrograms/ml than ovolactovegetarians (P < 0.01). Overall more women than men had low Zn concentrations; and these women generally had intakes below 6 mg/d. There was a significant correlation between serum Zn concentration and dietary Zn density in vegetarians, especially females (P < 0.001), but not in omnivores. Ovolactovegetarians did not have a significantly greater risk of low Zn status than omnivores.

Dietary intake and iron status of Australian vegetarian women

BACKGROUND

Despite the possible overall health benefits of a vegetarian diet, there is concern that some vegetarians and infrequent meat eaters, particularly females, may have inadequate iron status because of low or no heme-iron intakes.

OBJECTIVE

The objective was to investigate the nutritional intake and iron status of vegetarian women.

DESIGN

The nutritional intakes of 50 free-living vegetarian women aged 18-45 y and 24 age-matched omnivorous control women were assessed by using 12-d weighed dietary records. Iron status was assessed by measuring hemoglobin and serum ferritin concentrations.

RESULTS

There was no significant difference between mean (+/-SD) daily iron intakes of vegetarians and omnivores (10.7 +/- 4.4 and 9.9 +/- 2.9 mg, respectively), although heme-iron intakes were low in the vegetarians. Vegetarians had significantly lower intakes of protein (P < 0.01), saturated fat (P < 0.01), and cholesterol (P < 0.001), and significantly higher intakes of dietary fiber (P < 0.001) and vitamin C (P < 0.05). Mean serum ferritin concentrations were significantly lower (P = 0.025) in vegetarians (25.0 +/- 16.2 microg/L) than in omnivores (45.5 +/- 42.5 microg/L). However, similar numbers of vegetarians (18%) and omnivores (13%) had serum ferritin concentrations <12 microg/L, which is a value often used as an indicator of low iron stores. Hemoglobin concentrations were not significantly different.

CONCLUSION

It is important that both vegetarian and omnivorous women maintain an adequate iron status and follow dietary practices that enhance iron absorption.

Vegetarian food guide pyramid: a conceptual framework

The purpose of this article and the accompanying vegetarian food guide pyramid graphic is to provide the conceptual framework for the development of a new and unique food guide. Food guides for vegetarians have tended to be adaptations of guides developed for the general nonvegetarian population instead of being designed to emphasize the healthy components of vegetarian dietary patterns. A subcommittee of the organizers of the Third International Congress on Vegetarian Nutrition began a process that led to the development of a pyramid-shaped graphic illustration and a supporting document, both of which were introduced at the congress. The 5 major plant-based food groups (whole grains, legumes, vegetables, fruit, nuts, and seeds) form the trapezoid-shaped lower portion of the pyramid. Optional food groups, which may be avoided by some vegetarians (vegetable oils, dairy, eggs, and sweets), form the smaller, separate, triangle-shaped top portion of the pyramid. The supporting document discusses the concepts that affect vegetarian food guidance and the rationale for selecting the food groups. It is hoped that this framework will provide the impetus for further research and discussion and will lead to the development of a guide that is nutritionally adequate, is conducive to good health, and can be adopted by vegetarians of diverse eating practices.

Publication trends of vegetarian nutrition articles in biomedical literature, 1966-1995

We documented publication trends of vegetarian nutrition articles in biomedical literature between 1966 and 1995 using the National Institutes of Health MEDLINE bibliographic database. The publication rate of vegetarian articles increased steadily during the 3 decades, from an average of <10/y in the late 1960s to 76/y in the early 1990s. After adjusting for the total number of articles indexed in MEDLINE annually, we found that publication of vegetarian nutrition articles increased dramatically, by 4-fold, during the 1970s and reached an oscillating plateau during the 1980s. In the early 1990s, the proportion of vegetarian nutrition articles 8 articles per 1000 vegetarian nutrition articles and approximately 20 per 100000 articles indexed by MEDLINE. Non-nutrition journals have progressively published a larger share of all vegetarian articles in the biomedical literature during the period studied. The nature and study design of published vegetarian research has changed over the years as well. The proportion of original research and review articles increased whereas case series and letters to the editor decreased. Reports of epidemiologic studies of vegetarians with longitudinal designs have superseded cross-sectional designs in number and proportion. In 40% of all publications, preventive and therapeutic applications of vegetarian diets constituted the major themes of vegetarian articles in the decade of 1986-1995. However, 20 y earlier the main focus was on the nutritional adequacy of vegetarian diets. The progressive change in the themes of vegetarian nutrition publications is interpreted as a shift in the role of vegetarian diets in human nutrition.

Position of the American Dietetic Association: nutrition standards for child-care programs

ADA supports achievement of comprehensive nutrition standards in child-care programs. The standards presented in this position paper focus on meeting the child's nutrition needs and providing a safe and pleasant environment that promotes acquisition of eating habits that prevent disease and enable healthy growth and development. Dietetics professionals can play a powerful role in advocating and assisting the acceptance of child-care nutrition standards by parents, caregivers, foodservice personnel, and directors and policy makers for child-care programs.

Animal v. plant foods in human diets and health: is the historical record unequivocal?

An ideal diet is one that promotes optimal health and longevity. Throughout history, human societies have developed varieties of dietary patterns based on available food plants and animals that successfully supported growth and reproduction. As economies changed from scarcity to abundance, principal diet-related diseases have shifted from nutrient deficiencies to chronic diseases related to dietary excesses. This shift has led to increasing scientific consensus that eating more plant foods but fewer animal foods would best promote health. This consensus is based on research relating dietary factors to chronic disease risks, and to observations of exceptionally low chronic disease rates among people consuming vegetarian, Mediterranean and Asian diets. One challenge to this consensus is the idea that palaeolithic man consumed more meat than currently recommended, and that this pattern is genetically determined. If such exists, a genetic basis for ideal proportions of plant or animal foods is difficult to determine; hominoid primates are largely vegetarian, current hunter-gatherer groups rely on foods that can be obtained most conveniently, and the archeological record is insufficient to determine whether plants or animals predominated. Most evidence suggests that a shift to largely plant-based diets would reduce chronic disease risks among industrialized and rapidly-industrializing populations. The accomplish this shift, it will be necessary to overcome market-place barriers and to develop new policies that will encourage greater consumption of fruits, vegetables and grains as a means to promote public health.