Monday, May 1, 2017

Vegan Diet Does Not Reduce Risk of Metabolic Syndrome in a Taiwanese Cohort

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Shang et al report that Veganism does not reduce the risk of the metabolic syndrome in a Taiwanese cohort.

In fact, the risk of metabolic syndrome was 19-32% lower among Taiwanese who consumed animal products, than among those who were vegan, with the lowest relative risk among those who were fish eaters.

This study resonated with the Adventist Health Study report which also found no advantage of a vegan diet for reduction of risk of metabolic syndrome or other chronic disease patterns (MS). Shang et al. note that "This may be due to vegan diet further excludes fish, dairy products and egg, however the latter had more protective effect against on MS."

They note that eating fish provided n-3 fatty acids which protects against MS and heart disease mortality, and that eating dairy products provides calcium, potassium, and magnesium which may be beneficial for reducing the risk of MS, stroke and some cancers.  The vegan diet certainly contains less long-chain n-3 fatty acids than a diet containing fish and most vegan diets also contain less calcium than a diet containing dairy products, which has also been implicated in a finding of higher bone fracture risk among European vegans compared to non-vegans

Taiwanese vegans also had a higher risk of low HDL cholesterol compared to pescovegetarians and non-vegetarians

The higher incidence of low HDL levels among the Taiwanese vegans may have been due to a lower intake of fats.  

Not mentioned by these authors is the fact that "In humans, diets high in saturated fat and cholesterol raise HDL-cholesterol (HDL-C) levels."  Vegan diets are generally low in saturated fat and supply essentially no cholesterol.

This study is of particular interest because it has been asserted that low rates of chronic diseases among Chinese people are due to low intakes of animal products and that this implies that a diet lacking animal products is the best for reducing chronic disease risk.  Apparently this study shows that ethnic Chinese in Taiwan are best protected from metabolic syndrome and possibly heart disease mortality if they include animal products in their diets. 

In summary this study resonates with reports from the Adventist Health Study that have failed to find strong evidence that complete avoidance of animal products provides better health outcomes than omnivorous diets. 

1 comment:

FXScouse said...

This is a 2011 article and naturally does not discuss the most recent results reported from the considerably bigger North American 7th Day Adventist studies. Those show that "vegans" have the lowest average BMI of all groups.
It is not clear what could account for these differences although, of course, there are vegan diets and there are vegan diets. Also, it is possible that the differing reasons people in the two populations adopted such diets may have skewed the results. For example. more people in Taiwan may have adopted the diet because it is seen as a way of tackling overweight and other health issues as opposed to 7th Day Adventists who would presumably have been more likely to do so for religious reasons. Hence, the Taiwanese vegan group may have been more overweight and unhealthier to begin with. That is, reverse causation may explain the association. Hiowever, that would be speculation.