Scientific Update

A Review of Recent Scientific Papers Related to Vegetarianism

By Reed Mangels, PhD, RD, FADA

Motivations and Attitudes of Vegans

A study of German vegans provides insights into the reasons people are vegan and how they view animal agriculture. Researchers approached customers at seven vegan supermarkets in Germany and asked, "Do you follow a vegan diet?" If a customer said that they did, they were asked how often they made exceptions and ate animal products. Only those who never or extremely rarely ate an animal product were included in the study. A total of 329 vegans were surveyed. More than half were under the age of 35 and two-thirds were women. They had followed a vegan diet for an average of 3.8 years. Subjects were asked to name the most important reasons why they are vegan and could list up to three responses. They were also asked about their attitudes towards animals for food and treatment of farm animals. Close to 90% of respondents listed animal welfare/animal rights/animal agriculture as one of their main motives for being vegan. More than two-thirds said a motive for being vegan was personal health. Almost half mentioned environmental concerns. More than 80% of subjects had more than one main motive for being vegan, with 30% listing animals, personal health, and the environment as primary motives. A substantial majority (more than 80%) of subjects said "animals have similar feelings and fears as humans" and "all animals should be granted the right to a natural death." Regardless of their motivation for following a vegan diet, the majority of subjects were not willing to buy animal products even if the welfare of the animals was guaranteed. The results of this study could have implications for food producers. The authors of this study believe today's vegans may be an early indicator of a future trend. Similar to small numbers of consumers who were originally interested in organic foods or fair trade practices, the small number of vegans today may represent the beginning of a larger movement.

Janssen M, Busch C, Rôdiger M, Hamm U. 2016. Motives of consumers following a vegan diet and their attitudes towards animal agriculture. Appetite. 105:643-51.

New Ruling by the U.S. Food and Drug Administration Expands the Use of Vitamin D2

Traditionally, there are two forms of vitamin D — vitamin D2 which is vegan and vitamin D3 which is derived from lanolin from sheep's wool or fish oil. A vegan form of vitamin D3 has been recently developed but most commercial vitamin D3 is not vegan. The US Food and Drug Administration (FDA) recently made it easier for vegans to get vitamin D from fortified foods. The FDA ruled that vitamin D2 could be added to "milk alternatives" and "plant-based yogurt alternatives." Examples of "milk alternatives" include soy-, rice-, almond-, and coconut-based beverages, according to the FDA. Previously, vitamin D2 was approved for use in soy beverages, and soy-based cheese substitutes. Vitamin D (could be either D2 or D3 form) was previously approved for use in breakfast cereals, grain products, cow's milk and other dairy products, infant formula, and margarine. Vitamin D3 can be added to calcium-fortified fruit juices and fruit juice drinks, and other products. The new ruling about vitamin D2 in plant milks and plant yogurts took effect July 18, 2016.

Food Additives Permitted for Direct Addition to Food for Human Consumption; Vitamin D2 and Vitamin D3 (Final Rule). (July 18, 2016). Federal Register 81:137 46578-46582. Available at

What Does "Moderation" Mean, Anyway?

We've all heard it — "Eat whatever you want, in moderation" and "All foods can fit in a healthy diet if consumed in moderation." Researchers from the University of Georgia and Duke University decided to look into how people define moderation. They wondered if the concept of "moderation" actually helps people to make better food choices. In a series of studies, the researchers found that people identified "moderate consumption" as eating more of an unhealthy food than what one "should" consume. So, if you thought you "should" only eat one cookie, you might define moderate consumption as two cookies. "Moderate consumption" was said by research subjects to be eating less than what would be considered an indulgence. So, for those cookies, indulgence might be three cookies. The study got even more interesting when the researchers factored in how much subjects liked a food. They found that the more subjects liked a food, the larger a "moderate" serving would be. For example, subjects who liked gummy candies and who ate gummy candies often, thought that a larger number of gummy candies would be a moderate serving compared to people who didn't especially like gummy candies. Also, people tended to view whatever amount of a food that they commonly ate as being a "moderate" amount. So, if you really like pizza, a "moderate" serving might be 6 slices. The results of this study suggest that the concept of "eating in moderation" is meaningless and not a useful way to educate people about nutrition. As the researchers say, "Our results suggest that people may be adjusting their perceptions of moderation to justify their own intake, regardless of what that intake is."

VanDellen MR, Isherwood JC, Delose JE. 2016. How do people define moderation? Appetite. 101:156-62.

Canadian Diabetes Association Recommends Use of Plant-based Diet to Manage Type 2 Diabetes

Worldwide, more than 422 million people or about 1 in 12 adults has diabetes, mainly type 2 diabetes. Type 2 diabetes is due to the body's not being able to use the hormone insulin effectively and is often linked to excess weight and inadequate physical activity. In 2013, the Canadian Diabetes Association identified a plant-based diet as one of several diets that are recommended for use by people with type 2 diabetes. The recommended plant-based diet is defined as "a regimen that encourages whole, plant-based foods and discourages meats, dairy products and eggs as well as all refined and processed food." Many studies have compared plant-based diets to more traditional diets that have been used in the past to manage diabetes. Plant-based diets have been shown to be as good as or better than more traditional diets in helping people with diabetes manage their weight, control blood cholesterol, and improve symptoms of diabetes. Plant-based diets are well accepted by people with diabetes and can reduce the need for diabetes medicines. Family influence, a lack of knowledge about meal planning, and a desire for meat were the top barriers people reported for following a plant-based diet. They wanted to have more individual or group counseling sessions to allow them to learn more about the diet. With diabetes on the increase worldwide, we hope that more countries will follow Canada's lead and that practitioners will continue to work to develop educational materials that promote plant-based diets.

Rinaldi S, Campbell EE, Fournier J, O'Connor C, Madill J. 2016 Jul 28. A comprehensive review of the literature supporting recommendations from the Canadian Diabetes Association for the use of a plant-based diet for management of type 2 diabetes. Can J Diabetes. [Epub ahead of print]

Performance of Vegetarian Athletes

Many athletes choose to follow a vegetarian diet, with a goal of running faster or farther or otherwise improving performance. Vegetarian diets are often high carbohydrate which can help with endurance. A recent study examined reports of vegetarian diets and athletic performance to see if there was evidence for benefits or concerns. For this study, the researchers defined performance as strength, speed, endurance, and power; they did not look at flexibility or balance. They found eight studies of vegetarian diets and athletic performance that had been published earlier. The studies looked at resistance/strength training and at running events over a range of distances. The authors did not find either beneficial or harmful effects of a vegetarian diet; it did not improve or hinder performance. Since these conclusions were based on a small number of studies, additional research is needed to further explore the use of a vegetarian diet by athletes. At this point, however, there is no evidence of compromised performance due to the use of a vegetarian diet.

Craddock JC, Probst YC, Peoples GE. 2016. Vegetarian and omnivorous nutrition — comparing physical performance. Int J Sport Nutr Exerc Metab. 26:212-20.