The Food Journal and Food, Nutrition & Science

An alliance between The Lempert Report and The Center for Food Integrity

Vegetarian Diet Benefits

Vegetarian Diet Benefits

Health and Wellness

July 24, 2011

Vegetarian diets can be recommended for successful weight management without compromising diet quality, according to a recent study from Eastern Michigan University and published in The Journal of the American Dietetic Association. The study found that vegetarian diets are nutrient dense, consistent with dietary guidelines, and high in fiber and a large variety of other vitamins and minerals.

Researchers looked at a cross-sectional analysis of National Health and Nutrition Examination Survey (1999-2004) dietary and anthropometric data, focusing on participants aged 19 and older. All vegetarians were compared to all nonvegetarians. They found that mean intakes of fiber, vitamins A, C and E, thiamin, riboflavin, folate, calcium, magnesium, and iron were all higher for vegetarians than for all nonvegetarians. 

The findings are interesting in light of the common misconception that vegetarian diets are deficient in important nutrients like protein, vitamin B12, calcium, zinc, and iron – nutrients that most people get from animal foods. It seems difficult, says study author Bonnie Farmer, MS, RD, for many to understand that calcium can come from foods like greens and almonds and not just dairy, and that there is protein in vegetables, nuts, seeds, legumes, and grains and not just meat. In fact, Farmer points out, some studies have shown that vegans (those who eat no animal products) have higher iron intakes than both nonvegetarians and vegetarians who eat dairy and eggs.

“The 2010 Dietary Guidelines just issued are emphasizing a more plant-based diet for everyone, and USDA’s new ‘myplate’ shows that at least half of your diet should be fruits and vegetables, one-fourth should be grains, and only one-fourth protein foods. Even those who don’t want to be vegetarian could use this model to improve their intake of vitamins A and E, and magnesium,” says Farmer.

Although the protein intakes of vegetarians in the study were lower than the intakes of nonvegetarians, they were not lower than recommended amounts for adults. Typically, nonvegetarians exceed protein requirements, says Farmer, and higher protein intakes – particularly animal protein – are hypothesized to increase risk of some chronic conditions and diseases. Meanwhile, vegetarians were found to eat more dark leafy greens, legumes, and whole grains than nonvegetarians. Leafy greens provide calcium and iron, whole grains and legumes provide zinc, and all provide important contributions to protein intake. Farmers say that many vegetarians have learned over time to ensure that they have adequate intakes of the “problem nutrients” mentioned earlier, and gravitate to these foods for this reason.

Furthermore, vegetarian intakes of vitamin E, vitamin A, and magnesium exceeded that of nonvegetarians in the study, but both groups had intakes that were less than desired. One explanation for this, says Farmer, is that it’s possible that not all of the participants classified as vegetarian in the study were actually vegetarians. If they were, intake of these nutrients would likely have been higher, as vegetables, grains, and legumes are high sources of them. 

“I also think that many people who are new to vegetarianism tend to substitute things like pasta or cheese for meat instead of eating more vegetables, whole grains, and legumes,” says Farmer.

Having a registered dietitian involved would be the best way to educate consumers about vegetarian diets, says Farmer. She says that retailers could certainly suggest that a vegetarian diet could be an alternative for weight management, and that a registered dietitian can help consumers with planning the diet to ensure that their particular nutrient needs are met. People who are not familiar with vegetarian diets may need to learn how to ensure adequate intakes of nutrients such as calcium, iron and zinc.  

“As both a vegetarian and a registered dietitian, I think this information helps increase dietitians’ confidence that they can recommend a vegetarian diet without additional concerns with nutrient intakes,” Farmer adds. “Additionally, I hope that the information in this study will help dietitians fine-tune their counseling of clients who want to try vegetarian diets.”