Scientific Update
By Reed Mangels, PhD, RD, FADA
Vegan Diets for Companion Animals
How many companion animals (identified by this study's researchers as "pets") are
fed vegan diets? That's one question that researchers set out to answer when they
used an online questionnaire to survey 3,673 English-speaking "pet owners." A third
of those responding had dogs and cats, 51% had only dogs, and 16% only cats. More
than 6% of those people who responded were vegetarian (no meat or fish) and 5.8%
were vegan (no animal products). Some companion animals were sometimes fed
vegetarian or vegan foods (10% of dogs; 3% of cats). Exclusive feeding of vegan
diets to companion animals was reported only by vegans and by one vegetarian, with
1.6% of dogs and 0.7% of cats exclusively fed a vegan diet. The majority of these
diets were commercial with some homemade food included. About a quarter of vegans
fed their companion animals a vegan diet but more (78% of those who didn't) said
they would use a vegan diet for their animal if it met their standards. Over all,
about a third of people who did not already feed a vegan diet to their companion
animal indicated interest in doing so and wanted more information about nutritional
adequacy. This supports the need for additional research into the development of
nutritionally adequate vegan diets for companion animals.
Dodd SAS, Cave NJ, Adolphe JL, Shoveller AK, Verbrugghe A. 2019. Plant-based (vegan) diets for pets: A survey of pet owner attitudes and feeding practices. PLoS One. 14(1):e0210806.
Vegans May Have Lower Risk of Chronic Kidney Disease
Chronic kidney disease (CKD) affects more than 30 million adults in the U.S. and is
a major worldwide health problem. In this disease, the kidneys no longer work
properly and may eventually fail. Risk factors for CKD include diabetes, high blood
pressure, and heart disease. Does a vegan diet reduce the risk of CKD? To study
this, researchers in Taiwan asked more than 55,000 people who came to a hospital for
check-ups to complete a questionnaire, which asked about their diet and medical
history. Vegetarians (11,809) were those who reported eating eggs and/or dairy
products but no meat or fish; vegans (4,236) ate no animal products. Approximately
15% of vegans, 20% of vegetarians, and 16% of nonvegetarians had CKD. Vegans were
significantly less likely to have CKD compared to nonvegetarians. Additional
research is needed to see if the same effects are seen in vegans in other
countries.
Liu HW, Tsai WH, Liu JS, Kuo KL. 2019. Association of vegetarian diet with chronic kidney disease. Nutrients. 11(2). pii: E279.
O Canada!
Health Canada, a department of the Canadian government, recently released
Canada's Food Guide. In contrast to the United States' MyPlate,
there's no dairy group. Instead, the Canadian Food Guide calls for "making water
your drink of choice." Dairy products are included under the general heading of
Protein Foods where plant proteins are featured prominently. The Food Guide
states, "Protein foods, including plantbased protein foods, are an important part of
healthy eating. Include foods such as beans, lentils, nuts, seeds, lean meats and
poultry, fish, shellfish, eggs, lower fat milk and lower fat dairy products."
Canadians are urged to plan a couple of meatless meals a week and example meals are
vegan. The image of an ideal plate suggests that the recommended diet consists of
50% fruits and vegetables, 25% grains, and 25% protein foods. Yes, it would be even
better to see animal products excluded completely, but this Food Guide is a
refreshing change and one that we hope will be a model for the next MyPlate
update.
Government of Canada. 2019. Canada's Food Guide. www.food-guide.canada.ca/en/
Beware of Diets Based on Ultra-Processed Foods
Nutrition advice often includes a recommendation to avoid highly processed (also
called ultra-processed) foods. While we may intuit that these foods are not the best
choice, until now, no research had examined whether reducing the amount of these
foods offers health benefits. Researchers at the National Institutes of Health (NIH)
studied 20 healthy adults who for two weeks were given either a diet containing
mostly ultra-processed foods or one based on unprocessed foods. Neither diet was
vegetarian. After those two weeks, subjects were switched to the other diet for two
more weeks. An example of a dinner meal on the ultra-processed diet was a chicken
salad sandwich made with canned chicken, pickle relish, and mayonnaise on white
bread with cookies and canned peaches. An example of a dinner meal on the
unprocessed diet was an entr?e salad with lettuce, other vegetables, black beans
cooked from dried beans with a flaxseed oil and vinegar dressing; raw almonds; and
grapes. Meals were designed so that both ultraprocessed and unprocessed meals
offered to subjects would have similar amounts of calories, protein, fat,
carbohydrate, sodium, and fiber. Subjects could eat as much or as little of each
meal as they wanted to.
On average, when subjects received the ultraprocessed diet, they ate 460 calories more per day than when they ate the unprocessed diet. Subjects reported no difference in the pleasantness of each diet or their familiarity with foods on each diet, suggesting that their eating more calories on the ultra-processed regimen was not due to liking the foods more. They ate faster on the ultra-processed foods diet and gained about two pounds over the two weeks they were on this regimen. They lost an average of two pounds during the two weeks on the unprocessed diet. Although the diets used in this study were not vegan, it's certainly possible that a vegan diet based mainly on ultra-processed foods (frozen entr?es, chips, commercial baked goods and frozen desserts, for example) could lead to greater weight gain compared to a vegan diet based on unprocessed foods.
Hall KD, Ayuketah A, Brychta R, et al. Ultraprocessed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell Metab. 2019; S1550-131(19)30248-l.
Vegan Diet Meets Needs of Recreational Runners
By Lauren Capano, Dietetic Intern, College of Saint Elizabeth
Physical activity is an important component of health and well-being. Nutrition is key for sustaining and improving physical fitness. Many active people are adopting vegan or vegetarian lifestyles, but how do these diets affect performance compared to the traditional omnivorous diets of some athletes?
German scientists recruited 76 runners who typically ran two to five days a week. Participants were designated as vegan, lacto-ovo-vegetarian (LOV), or omnivorous depending on their response to questions about their diet over the past 6 months. Groups reported similar calorie and protein intakes. The vegans' diets were significantly higher in carbohydrates, fiber, magnesium, folate, and vitamin E compared to the LOVs' and omnivores' diets. No difference in performance was detected between the three groups. Vegan male and female athletes were able to reach a similar maximum power on stationary exercise bikes for their body weights as compared to the other athletes. They also found that diet did not affect the athletes' ability to use energy in their muscles from low to maximum power — meaning the vegan athletes' abilities were similar no matter how intense the exercise.1
The same scientists compared the micronutrient status of 81 vegan, LOV, and omnivorous recreational runners. Inadequate micronutrient status may negatively affect performance, and so it is important that the athletes' diets provide enough of these nutrients. Micronutrient status was determined by blood tests. Overall, the three groups had similar, adequate vitamin B12, folate, vitamin D, and iron status. Vegan athletes not taking a vitamin B12 supplement were more likely to have low, but still adequate, levels of the vitamin. Athletes in all three groups who were not taking a vitamin D supplement were the only ones with low to deficient vitamin D levels.2
1 Nebl J, Haufe S, Eigendorf J, et al. Exercise capacity of vegan, lacto-ovo-vegetarian and omnivorous recreational runners. J Int Soc Sports Nutr. 2019; 16:23.
2 Nebl J, Schuchardt JP, Strohle A, et al. Micronutrient status of recreational runners with vegetarian or non-vegetarian dietary patterns. Nutrients. 2019; 11:146.
