by Monte Sahlin

By AT News Team, May 13, 2014

An article in the journal PLOS One has reported a study conducted by researchers at the Medical University of Graz, Austria, which concludes that, in the population studied, vegetarians suffer from higher risk of asthma, cancer, allergies, and poor mental health, compared to their meat-eating counterparts. PLOS One  is an international, peer-reviewed, open-access, online publication dedicated to rapid dissemination of research from all scientific disciplines.

While vegetarians may have a lower body mass index (BMI), vegetarian diets were shown to be tied to generally poorer health, poorer quality of life, and a higher need for health care than their meat-eating counterparts in Austria.  Also, according to the report, a vegetarian diet characterized by a low consumption of saturated fats and cholesterol that includes increased intake of fruits, vegetables and whole-grain products carries elevated risks of cancer, allergies and mental health disorders.

The study surveyed more than 15,000 people, a mix of vegetarians, vegetarians who eat eggs and cheese, and meat-eaters. The results showed that more than 30 percent of vegetarians surveyed had allergies, while less than 17 percent of participants who regularly included meat in their diet had allergies. Vegetarians also had a 50 percent increase in heart attacks and a 50 percent increase in incidences of cancers.

In the report vegetarians are found to have some elements of healthier lifestyles. They are less likely to smoke tobacco and also drink less alcohol. The research also found that vegetarians were more physically active, had better socioeconomic status, and had better health behaviors overall.

“Our study has shown that Austrian adults who consume a vegetarian diet are less healthy (in terms of cancer, allergies, and mental health disorders), have a lower quality of life, and also require more medical treatment," the researchers conclude. "Therefore, a continued strong public health program for Austria is required in order to reduce the health risk due to nutritional factors.”

Response from Adventist Health Study Research Team

Because many studies of Seventh-day Adventists have had significantly different findings, Adventist Today asked for comments from researchers at Loma Linda University (LLU) who have worked on these projects under grants from the National Institutes of Health (NIH). Dr. Gary Fraser and Dr. Pramil Singh of the LLU School of Public Health stated,  "We congratulate the authors on their study of Austrian vegetarians. As the authors point out it is not possible with this study design to decide whether associations are causal in the direction of diet causing or preventing disease."

"It is well known that many subjects who experience chronic disease, including cancer, may gravitate toward a plant-based diet. Then the association results from causation in the reverse direction i.e. disease causes a dietary preference. It would have been helpful to know about past dietary habits and the duration of the diets in the Austrian study. Thus we suggest that this study is an interesting sociological description of vegetarians in Austria as compared to others, but has little to say about the cause of disease."

"Interestingly, our data on U.S. vegetarians also suggests that they are less likely to participate in preventive health testing against cancer(see notes 1 and 2 below), although as distinct from the Austrian findings, vegetarians that we study longitudinally have lower rates of many common chronic diseases ( see notes 3-5). 

"A previous longitudinal study of German vegetarians has also found that they experienced much lower mortality from cancer, cardiovascular disease, and lower total mortality (6). British vegetarians may also derive some benefits (see notes 7 and 8), but perhaps less clearly so.

"U.S. vegetarians as compared to non-vegetarians in our studies do seem to experience better mental health (see notes 9 and 10), a finding that differs from the Austrian data, perhaps reflecting different motivations for the dietary choices. So findings among studies of vegetarians are somewhat diverse for some disease endpoints, and this is perhaps not surprising as vegetarians worldwide have diets that may differ greatly. Thus one would not expect the same health consequences in U.S., British, Austrian, German, and Indian vegetarians, as we have previously discussed (see note 11).

"We would strongly suggest that studies of vegetarians describe their diets with additional qualifiers that will allow the reader to understand more clearly what the study participants are actually eating, this both in terms of nutrients, vitamins, minerals, and also particular foods and food groups (see note 12)."

Reference notes attached to the statement from  Gary E. Fraser MD, Ph.D.; Pramil Singh DrPH

1. Ibrayev Y, Oda K, Fraser GE, Knutsen SF. Utilization of prostate cancer screening according to dietary patterns and other demographic variables. The Adventist Health Study-2.  J Cancer. 2013 Jun 28;4(5):416-26. doi: 10.7150/jca.6442.

2. Ibrayev Y, Oda K, Dang K. et al.  Utilization of colorectal cancer screening in persons with different dietary patterns. The Adventist Health Study-2.  American Journal of Epidemiology Volume: 175 Supplement: 11 Pages: S29-S29 Published: JUN 15 2012

3. Fraser GE. Diet Life Expectancy and Chronic Disease. Studies of Seventh-day Adventists and other vegetarians. Oxford University Press, New York, 2003.

4. Orlich MJ1, Singh PN, Sabaté J, Jaceldo-Siegl K, Fan J, Knutsen S, Beeson WL, Fraser GE. Vegetarian dietary patterns and mortality in Adventist Health Study 2. JAMA Intern Med. 2013 Jul 8;173(13):1230-8. doi: 10.1001/jamainternmed.2013.6473.

5. Tantamango-Bartley Y1, Jaceldo-Siegl K, Fan J, Fraser G. Cancer Epidemiol Biomarkers Prev. Vegetarian diets and the incidence of cancer in a low-risk population. 2013 Feb;22(2):286-94. doi: 10.1158/1055-9965.EPI-12-1060. Epub 2012 Nov 20.

6. Frentzel-Beyme R, Chang-Claude J. Vegetarian diets and colon cancer: the German experience.  Am J Clin  Nutr. 1994; 59 (supp): 1143S-1152S.

7. Key TJ1, Appleby PN, Spencer EA, Travis RC, Allen NE, Thorogood M, Mann JI. Cancer incidence in British vegetarians.  Br J Cancer. 2009 Jul 7;101(1):192-7. doi: 10.1038/sj.bjc.6605098. Epub 2009 Jun 16.

8. Crowe FL1, Appleby PN, Travis RC, Key TJ. Am J Clin Nutr. Risk of hospitalization or death from ischemic heart disease among British vegetarians and nonvegetarians: results from the EPIC-Oxford cohort study. 2013 Mar;97(3):597-603. doi: 10.3945/ajcn.112.044073. Epub 2013 Jan 30.

9. Ford PA,  Jaceldo-Siegl K, Lee JW, Youngberg W, Tonstad S. Intake of Mediterranean foods associated with positive affect and low negative affect.  2013; J Psychosom Res. 74(2):142-8. doi: 10.1016/j.jpsychores.2012.11.002. Epub 2012 Nov 22

10. Lee JW, Morton KR, Walters J, Bellinger DL, Butler TL, Wilson C, Walsh E, Ellison CG, McKenzie MM, Fraser GE.  Cohort profile: The biopsychosocial religion and health study (BRHS).  Int J Epidemiol. 2009 Dec;38(6):1470-8. doi: 10.1093/ije/dyn244. Epub 2008 Dec 3.

11. Fraser GE. Vegetarian diets: what do we know of their effects on common chronic diseases? Am J Clin Nutr. 2009 May;89(5):1607S-1612S. doi: 10.3945/ajcn.2009.26736K. Epub 2009 Mar 25. Review. Erratum in: Am J Clin Nutr. 2009 Jul;90(1):248.

12. Rizzo NS, Jaceldo-Siegl K, Sabate J, Fraser GE. Nutrient profiles of vegetarian and nonvegetarian dietary patterns.  J Acad Nutr Diet. 2013 Dec;113(12):1610-9. doi: 10.1016/j.jand.2013.06.349. Epub 2013 Aug 27.