Scientific Update

By Reed Mangels, PhD, RD, FADA

AND's New Position on Vegetarian Diets

The Academy of Nutrition and Dietetics (AND), the world's largest organization of food and nutrition professionals, recently published a new position paper about vegetarian diets. AND's position paper provides current information about key nutrients for vegetarians, vegetarian diets for different stages of the life cycle, and the role of vegetarian diets in prevention and treatment of chronic diseases such as obesity, heart disease, high blood pressure, diabetes, and cancer. The paper defines vegetarian diets as "diets that are devoid of flesh foods (such as meat, poultry, wild game, seafood, and their products)" and lists vegan, lacto-ovo, and lacto vegetarian diets as examples of types of vegetarian diets. Environmental benefits of vegetarian diets are also discussed. VRG's polls of the number of vegetarian adults are featured in the paper and VRG's Vegan Plate ( is identified as a useful resource. The Academy's paper is a helpful source of information for the media, healthcare professionals, and others with questions about vegetarianism. The complete position paper is available at: (

Melina V, Craig W, Levin S. 2016. Position of the Academy of Nutrition and Dietetics: Vegetarian diets. J Acad Nutr Diet. 116:1970-1980.

Fruits and Vegetables and Depression

Plant foods contain many health-promoting substances, called phytochemicals, also known as "plant chemicals." One type of phytochemical is called flavonoids. Flavonoids are found in fruits, vegetables, grains, herbs, and beverages. Researchers looked at more than 80,000 women's intakes of flavonoids by asking them about the foods they commonly ate. They also asked the women whether or not they had been treated for depression. Women with the highest intakes of flavonoids had a 7-10% lower risk of depression compared to women with the lowest intake. This reduced risk of depression was especially seen in women age 65 and older. The foods most strongly associated with a reduced risk of depression were citrus fruits and juices, like orange and grapefruit. Tea was also associated with a lower risk of depression. Although further study is needed, these results suggest that eating a variety of fruits, vegetables, and grains may help to reduce the risk of depression in women. No results were available for men.

Chang SC, Cassidy A, Willett WC, Rimm EB, O'Reilly EJ, Okereke OI. 2016. Dietary flavonoid intake and risk of incident depression in midlife and older women. Am J Clin Nutr. 10:704-14.

Vegetarian Athletes

Many athletes choose to follow a vegetarian diet and may wonder if their diet choice affects their athletic performance. Most studies of vegetarian diets in athletes put non-vegetarians on vegetarian diets for a short time and see if that affects performance. These studies don't reflect long-term use of vegetarian diets. Researchers recently compared 27 vegetarian (15 of the vegetarians were vegan) and 43 non-vegetarian athletes, all of whom were either on a competitive club sports team at an NCAA Division 1 university or were training for a major event such as a marathon or triathlon. Study participants had been vegetarian for at least three months; most had followed their diet for more than two years. Female vegetarians had greater cardiorespiratory fitness than female nonvegetarians; there was no significant difference in males. Vegetarians and nonvegetarians were not significantly different in terms of strength. These results suggest that vegetarian diets do not compromise strength and may be advantageous for aerobic fitness.

Lynch HM, Wharton CM, Johnston CS. 2016. Cardiorespiratory fitness and peak torque differences between vegetarian and omnivore endurance athletes: a cross-sectional study. Nutrients. 15;8(11). pii: E726.

Alternative Plant Milks

Three food scientists from India recently projected that the market for plant milks would grow to reach a value of $14 billion by 2018. They see plant milks being increasingly used to meet the needs of the many people in the world who are lactose intolerant or are allergic to cow's milk. They point out a number of substances, in addition to soy, rice, almonds, cashews, oats, hemp, and coconut that are either being used internationally or could be used to make plant milks. Some of their ideas include peanuts, lupin, corn, spelt, teff, amaranth, and quinoa. Lupin, a plant in the legume family, seems especially promising because it is high in protein and fiber and low in fat, and could potentially be used in the same way that soybeans are used. They predict that blends of different kinds of plant milk will become popular because combining products can improve the overall nutritional profile.

Sethi S, Tyagi SK, Anurag RK. 2016. Plant-based milk alternatives an emerging segment of functional beverages: a review. J Food Sci Technol. 53:3408-3423.

Fruits and Vegetables Don't Overcome Red Meat

Eating a lot of red and processed meat is associated with a greater risk of heart disease and cancer and of dying earlier. Eating a lot of fruits and vegetables is associated with living longer. What happens if someone eats a lot of red/processed meat and a lot of fruits and vegetables? Swedish researchers set out to answer this question. They studied more than 70,000 Swedish men and women who were asked about their food habits several times over a 16-year period. Those eating the most red/processed meat had a 21% higher risk of overall mortality and a 29% higher risk of dying from heart disease. These risks were not affected by fruit and vegetable consumption. Risks were similar in those eating the most red/processed meat who ate few fruits and vegetables and who ate lots of fruits and vegetables. Overall, processed meat seemed to be associated with the greatest risks. These results suggest that eating a lot of fruits and vegetables will not counterbalance the apparently harmful effects of eating a red/processed meat-centered diet.

Bellavia A, Stilling F, Wolk A. 2016. High red meat intake and all-cause cardiovascular and cancer mortality: is the risk modified by fruit and vegetable intake? Am J Clin Nutr. 104:1137-1143.

Whole Grain Benefits

Whole grains — foods like whole-wheat bread and pasta, brown rice, quinoa, and oatmeal — are foods we're often told to eat more of. People who eat plenty of whole grains tend to have a lower risk of developing heart disease, diabetes, and some kinds of cancer. New studies have taken a fresh look at whole grains.

The first study was of 33 middle-aged adults (less than 50 years old) who were overweight or obese. For eight weeks, the study subjects ate a diet high in wholegrains, they took a 10 week break, and then were given a diet high in refined grains for eight weeks. Sauces and packaging were used to disguise the diets so subjects didn't know which grains they were getting. After eating whole grains for eight weeks, subjects' diastolic blood pressure was lowered by 8%. Diastolic blood pressure is the bottom number when blood pressure is reported. For example, if your blood pressure is 120/80, 80 is your diastolic blood pressure. What does this all mean? Well, elevated diastolic blood pressure is a risk factor for heart disease in middle-aged adults. If it's lowered to the extent that it was in this study, it could mean that a person's risk of dying from heart disease would be about 30% less and of dying from a stroke would be about 40% less. Eating more whole grains (and fewer refined grains) seems to help to control blood pressure and may reduce the risk of heart disease.

The second study looked at gum disease in over 6000 adults. Study subjects completed records of what they ate for several days and were examined. About 45% of them had gum disease, of varying severity. Study subjects eating the lowest amount of whole grains were about 30% more likely to have worse gum disease than those eating the highest amount of whole grains. Eating more fruits and vegetables was not associated with a lower risk of gum disease.

Kirwan JP, Malin SK, Scelsi AR, et al. 2016. A wholegrain diet reduces cardiovascular risk factors in overweight and obese adults: a randomized controlled trial. J Nutr. 146:2244-2251.

Nielsen SJ, Trak-Fellermeier MA, Joshipura K, Dye BA. 2016. Dietary fiber intake is inversely associated with periodontal disease among US adults. J Nutr [Epub ahead of print]