Scientific Update
By Reed Mangels, PhD, RD
Lower Risk of Diabetes in Vegetarian Men
Diabetes affects millions of people worldwide. In the U.S. alone, more than 9% of people have diabetes; among those age 65 and older, 1 in 4 have diabetes. Clearly, identifying ways to reduce the incidence of diabetes is important, both for individual well-being and to reduce health care costs associated with diabetes. Could a vegetarian diet help? A recent study suggests that it could. In this study, results from 14 studies were combined using a powerful statistical technique called meta-analysis. The meta-analysis determined that those choosing to follow a vegetarian diet had a 27% lower risk of developing diabetes than did non-vegetarians. This reduced risk was seen in vegans and in lacto-ovo, lacto, and ovo vegetarians. When men and women were looked at separately, vegetarian men had a lower risk of having diabetes than did non-vegetarian men; no difference was seen in diabetes incidence in vegetarian women compared to non-vegetarian women. Results show promise that a vegetarian diet may reduce the risk of developing diabetes, especially in men.
Lee Y. Adherence to a vegetarian diet and diabetes risk: a systematic review and meta-analysis of observational studies. Nutrients. 2017 Jun 14;9(6). pii: E603.
Vegetarians & Weight Loss
Weight loss surgery is done to help people with extreme obesity lose weight. There are different kinds of weight loss surgery. Some limit the amount of food a person can eat by shrinking the size of the stomach. Others also affect how many calories and nutrients a person can absorb. In 2015, almost 200,000 people in the U.S. had weight loss surgery. A recent study from Israel looked at people who were "vegetarians" and who opted to have weight loss surgery. The researchers compared 21 "vegetarians" to 1449 non-vegetarians. The "vegetarian" group included 4 people who ate fish and 5 vegans. Most chose to be "vegetarian" for ethical reasons and had been "vegetarian" for an average of 17 years. "Vegetarians" had lower blood sugar levels before surgery but had similar rates of hypertension, and sleep apnea. "Vegetarians" were more likely to use iron and vitamin B12 supplements than were non-vegetarians. No information was provided about how the groups did after surgery. The study authors point out that after surgery, careful meal planning is needed. They developed nutritional recommendations for vegetarians and vegans following weight loss surgery. These include:
- 0.5-0.7 grams of protein per pound ideal body weight
- Consume a variety of plant-based proteins
- Consume foods high in iron and use an iron supplement providing 45-60 mg of iron per day
- Consume foods high in zinc and use a multi-vitamin that contains 8-22 mg of zinc daily
- Get 1200-2400 mg of calcium per day from food and supplements
- Use a multivitamin that includes iodine and other minerals
- Use vitamin B12 supplements as recommended by your health care provider
- Vitamin D supplements are recommend after surgery but the amount and whether or not a supplement is needed depends on serum vitamin D levels
In addition, it's important to consult with a registered dietitian with expertise in vegetarian nutrition.
Sherf-Dagan S, Hod K, Buch A, et al. Health and nutritional status of vegetarian candidates for bariatric surgery and practical recommendations. Obes Surg. 2017 Jul 11. [Epub ahead of print]
Veggies in Breastmilk
The facts about vegetables and children are sobering. One in four toddlers in the U.S. does not eat even one vegetable in a day. We're hopeful that vegetarian children do better than this. Still, many children don't care for vegetables, perhaps because they taste bitter or strange. Research has shown that babies learn about the taste of vegetables early in life through the flavors in their mothers' milk. In other words, the mother eats broccoli and some of the flavor of the broccoli appears in her breastmilk. The more varied the mother's diet is, the more varied the flavor of her milk. This could help babies be more familiar with the taste of veggies, even before they are given vegetables to eat. It could also explain why children who were breastfed and therefore experienced a variety of flavors, are less likely to be picky eaters than children who were fed infant formula. A recent study had women who breastfed their infants drink carrot, beet, vegetable, or celery juice daily, starting when their babies were 2 weeks old. Other women did not drink vegetable juices. The babies who had been exposed to the taste of vegetables from an early age were more likely to accept cereal made with carrot juice. Although it was not studied, it is likely that having mothers eat a variety of vegetables (instead of drinking juice) would have the same effect.
Mennella JA, Daniels LM, Reiter AR. Learning to like vegetables during breastfeeding: a randomized clinical trial of lactating mothers and infants. Am J Clin Nutr. 2017;106:67-76.
B12 Fortified Toothpaste
Researchers in Germany developed a vitamin B12 fortified toothpaste. They conducted a trial of this product with 76 vegan adults who either brushed 2 times a day with the vitamin B12 toothpaste or with a placebo for 3 months. At the end of the trial, the group using the fortified toothpaste had higher blood levels of vitamin B12. The increase in blood vitamin B12 levels was greatest in vegans who had not ever used vitamin B12 supplements. This study suggests that vitamin B12-fortified toothpaste can be an effective way to improve vitamin B12 status, especially in those who do not use vitamin B12 supplements.
Siebert AK, Obeid R, Weder S, et al. Vitamin B-12-fortified toothpaste improves vitamin status in vegans: a 12-wk randomized placebo-controlled study. Am J Clin Nutr. 2017;105:618-625.
Fewer Eating Disorders
As we've reported before, studies finding that so-called "vegetarians" who eat chicken and/or fish are at a higher risk for eating disorders than actual vegetarians and those who don't claim to be vegetarians (see Vegetarian Journal, Issue 2, 2012). A recent study looked at eating behaviors and attitudes of vegans, a group often under-represented in studies of vegetarians. The researchers compared 358 vegans and 220 non-vegetarians. All subjects were over 18 and similar in terms of demographics. Subjects self-identified as vegans, meaning "they refrained from all animal products." Study subjects completed an online survey that assessed their attitudes towards food and their risk for having an eating disorder. Vegans were more likely to consider themselves healthy and to frequently eat fruits, vegetables, beans, nuts, and grains. They were less likely to be concerned about eating or about their body shape than were non-vegetarians. They also scored lower on a test measuring problematic eating behavior. This lower score means they were less likely to have an eating disorder. Scores on other tests of eating behavior were similar in vegans and non-vegetarians.
Heiss S, Coffino JA, Hormes JM. Eating and health behaviors in vegans compared to omnivores: Dispelling common myths. Appetite. 2017;118:129-135.
Milk and Children's Height
A recent study looked at approximately 5000 Canadian children age 2-3 years old and asked how many cups of cow's milk and what the researchers called "noncow milk" they drank per day. "Noncow milk" could include soy, rice, goat, or other milk; this category was not exclusively plant milks. About 13% of children drank "noncow milk" on a typical day. The headline-making news was that children drinking the most "noncow milk" tended to be shorter than the children drinking the most cow's milk. At age 3 years, a child drinking 3 cups of "noncow milk" daily would be expected to be about half an inch shorter than a child drinking 3 cups of cow's milk. This study is problematic because of a number of issues including that it looked at "noncow milk" as a single group and that no information was included about the other foods and beverages in the children's diet. Beverages such as soy, almond, and rice milk vary widely in the amount of calories, protein, vitamins, and minerals they provide. Soy milk, for example, has a protein and calorie content similar to that of low-fat cow's milk while other plant milks tend to supply less protein and calories. Other dietary factors could have influenced the children's growth but were not investigated.
Morency ME, Birken CS, Lebovic G, et al. Association between noncow milk beverage consumption and childhood height. Am J Clin Nutr. 2017;106:597-602.
