Austrian Vegetarians: Good News?
A study was released a couple weeks ago from Austria – a cross-sectional survey of eating habits and various health outcomes. But it has so many issues that I don’t think it’s worth commenting on except in the interest of being thorough in documenting the research on vegetarians.
Trying to infer dietary effects on health by using cross-sectional studies is always fraught with problems, but this study had even more than usual.
The diet categories included vegan, lacto-ovo-vegetarian, and pesco-vegetarian which was fine; in the final analysis all of these were grouped as “vegetarians.” The remaining diet groups were:
– carnivorous diet rich in fruits and vegetables
– carnivorous diet less rich in meat
– carnivorous diet rich in meat
This is unusual, and they didn’t define them even for the participants when they were asking them which category they belonged to.
For the health outcomes, instead of a list of diseases and incidence rates, they created a number of indicators that I would not have much confidence in. Finally, their p-values made little sense to me.
To sum up their findings, they say, “Both a vegetarian diet and a carnivorous diet rich in fruits and vegetables were related to the best self-rated health and the lowest incidence of chronic conditions. However, the quality of life was better in subjects who consume a carnivorous diet rich in meat. Nevertheless, as diets rich in fruits and vegetables were associated with better health as well as better health-related behavior, these diets should be recommended, and public health programs will be needed to reduce the health risk due to nutritional factors.”
So for what it’s worth, I suppose this is good news.
References
1. Burkert NT, Freidl W, Großschädel F, Muckenhuber J, Stronegger WJ, Rásky E. Nutrition and health: different forms of diet and their relationship with various health parameters among Austrian adults. Wien Klin Wochenschr. 2013 Dec 17. [Epub ahead of print] | link
January 4th, 2014 at 4:00 am
I wouldn’t put much stock in a cross-sectional study. If they had more than a handful of people like me in it — individuals who started down the road to a plant-based diet for health issues — it would be completely confounded by self-selection bias. (though later the ethical issues predominate for me). Actually that problem applies to any type of observational study including cohort, case-control and ecological, but it just seems to be much more severe for cross-sectional studies, because they lack the temporal relationship of “exposure A precedes outcome B”.
I am not sure I can understand why carnivorous diets lead to better quality of life, unless it allows people to fit in more to Austrian society. It depends on whom they survey. If they were looking at people living on a vegan commune, or hipsters living in California, then maybe a vegan diet would have better quality of life and social “fit”. Of course, it’s possible they are talking about health-related quality of life but people are not compartments (social, health, psychological, physical, mental, spiritual, ethical all overlap tremendously).
January 7th, 2014 at 8:32 pm
My thoughts exactly. Define quality of life and identify who’s doing the defining.
February 11th, 2014 at 1:08 pm
Ordinary restaurants in Austria don’t have many choices for vegans (save for Asian ones), but 2 of the largest cities, Vienna and Graz, have many vegan restaurants (and a lot of vegan products in stores). Now, I guess a vegetarian who socializes only with meat-eaters doesn’t experience much of these.