Vegetarians Get a Bad Rap

by Jack Dini

A post showing vegetarians and veggies tend to have significantly more mental disorders and health issues than meat-loving people has gone viral, being shared or liked at Facebook over a quarter million times reports Pierre Gosselin.

A study from the University of Graz, Austria, suggests there is an association between a vegetarian diet and an increased risk of certain chronic diseases. (2)

However, as NHS in the UK points out, “Before any meat eating readers start feeling smug, the study provides no proof that vegetarians are in poorer health than meat eaters.” (3)

This was an Austrian survey which simply took a group of 330 people put into a general 'vegetarian' category (some in this category were not exclusively vegetarian). They were matched with groups of people from three 'carnivorous' categories ranked in terms of total meat consumption.

The 'vegetarians' had lower body mass Index (BMI) and alcohol intake, but they also had increased prevalence of three chronic diseases: allergies, cancer and mental illness.

Since the research included a relatively small sample of only 330 vegetarians, the prevalence of the 18 diseases questioned in this group could differ from another group, meaning the associations with the three diseases could purely be due to chance. (3)

There were also inaccuracies in reports that vegetarians were 50% more likely to have a heart attack. There was no significant difference between the vegetarians and three carnivorous groups for any cardiovascular diseases questioned—history of heart attack, high blood pressure, stroke or diabetes.

Ross Pomeroy adds, “The study has a host of inescapable limitations. All of the data, including diet information, is self-reported, thus, we have no idea precisely what vegetarians or the various meat-consuming groups were actually eating. The authors admit, “No statements can be made whether the poorer health in vegetarians in our study is caused by their dietary habit or if they consume this form of diet due to their poorer health status.” Moreover, the study was based in Austria, and the Austrian diet and lifestyle significantly differs from the American diet and lifestyle.” (4)

Even if the study wasn't severely limited, it wouldn't be enough to overturn prior evidence. In a 2009 review, the Academy of Nutrition and Dietetics (formerly the American Dietetic Association), the largest organization of food and nutrition professionals in the US, declared that appropriately planned vegetarian diets, including total vegetarian or vegan diets, are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases. More recently, a 2012 review published in the journal Public Health Nutrition, found that vegetarian diets have not shown any adverse effects on health. (4)

Since the sample size was small, its worth discussing observations from John Ioannidis of Stanford. He is well know for his advocacy in examining the biases and reproducibility of published science. In one of his reports, he looked at 45 studies published between 1990 and 2003 and found that subsequent research contradicted the results of seven of those studies (16%), and another seven were found to have weaker results than originally published. In other words, 32% did not withstand the test of time. (5)

In a number of cases the explanation for the discrepancies was sample size. The smaller the group, the shorter the study, the more likely it was that subsequent, deeper, investigation, would contradict or alter the original thesis. Ioannidis provides numerous examples supporting this.

So, instead of all the publicity surrounding the Austrian study, the choice of vegetarianism is supported by studies that are much more thorough and have positive results.

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References

1. Pierre Gosselin, “The hazards of vegetarianism: U of Graz study showing vegetarians are unhealthier, more mentally disturbed, goes viral,” notrickszone.com February 5, 2015

2. Nathalie T. Burket et al., “Nutrition and health-the association between eating behavior and various health parameters: a matched sample study,” PLOS, Volume 9, Issue 2, February 2014

3. “Vegetarians have 'poorer quality of life' study claims,” nhs.uk/news, April 4, 2014

4. Ross Pomeroy, “Large study finds vegetarians have poorer health, lower quality of life than meat eaters,” realclearscience.com, April 4, 2014

5. John P. A. Ioannidis, “Contradicted and initially stronger effects in highly cited clinical research,” JAMA, 294 (2), 218 (July 13, 2005)