UK Study Discovered Link Between Vegetarian Diet and Increased Risk of Stroke

A study done in the UK found a link between a vegetarian diet and an increased risk of stroke. However, one should not rush to the nearest butcher shop

In the media, we have recently heard about a surprising new study. How surprising? Contrary to popular belief that vegetarianism is healthy and beneficial to the body, it has been claimed by this study that this lifestyle increases the risk of stroke. 

However, when looking at the findings in depth, the conclusiosn are far less conclusive then the claims.

As part of a larger study called EPIC-Oxford : An Acronym for "European Prospective Investigation into Cancer and Nutrition". 

This is part of an integrated pan-European study that began in 1992 with the aim of examining the relationship between dietary habits, lifestyle, environmental factors, cancer and other chronic diseases.

EPIC-Oxford tracks around 48,000 UK participants recruited between 1993 and 2001 for a follow-up period that is currently 18 years on average. 

By proactively addressing the participants, the researchers say that the research group will be diverse in terms of dietary habits and include meat eaters, vegetarians, and those who avoid most meat but eat fish. 

All participants were healthy at baseline, with no history of heart disease, stroke or other cardiovascular disease. 

This is how a large group of participants was built, with the information gathered over the years can be used to examine many issues.

Such studies are called observational studies, as researchers do not make any intervention in the participants' lifestyle.

For example, they were not asked to change their dietary habits - but merely collect data on them. 

Because of this, observational studies cannot show cause and effect, but only show a causal relationship between two or more factors.

That is, they cannot be inferred from mechanisms by which a particular diet leads to improvement or worsening in a particular medical condition, but only to point to a statistical correlation between the type of diet and the medical condition.

Vegetarian Diet and Increased Risk of Stroke
Brain MRI scan after stroke. Photo: Science Photo Library

Link between nutrition and stroke?

In the present article, the researchers separated the data on European study participants into three groups: 
  1. meat eaters 
  2. fish eaters 
  3. vegetarians
Researchers examined the risk of each group's members getting heart disease or having a stroke. 

It was found that the risk of fish eaters or vegetarians having a heart disease was 13 percent and 22 percent, respectively, compared to meat eaters. 

In addition, it is found that for vegetarians to experience a stroke is 20 percent more then members of the other two groups. 

A big difference? 

Depending on how you look at it. You can put it this way too: For ten years, every thousand fish eaters will have 5.8 less cases of heart disease than a thousand meat eaters, and for vegetarians ten cases. 

Also, three more vegetarians out of every thousand will suffer from stroke during this period, compared to the number of patients eating meat or fish.

The results show that those who avoid eating meat suffer less from heart disease than expected, since the average body weight of members of this group is also lower, and they are less likely to suffer from high blood pressure and high blood lipid levels. 

The relative increase in their stroke rate sounds surprising. 

Because of the nature of the cerebral events in question, researchers speculate that vegetarians may suffer from deficiency of vitamins such as B- 12, and low levels of lipids, which can lead to bleeding from blood vessels. However, this is currently only a hypothesis.

The editors of the BMJ medical journal in which the article was published dedicated the editorial to him

The authors, Mark Lawrence and Sarah McNaughton, claim that while the research group is very large and the statistics were done properly, it is the result of one study and a fairly moderate increase in stroke cases. 

Further studies are needed to verify the existence of the risk For vegetarians. 

It should also be borne in mind that the study was conducted only on a British population, and it is not necessarily possible to discard it from vegetarian groups elsewhere in the world whose dietary habits may differ.

Other doctors who were asked to respond to the article also stated that vegetarians should not be alarmed.

First, they note that, according to the study, people who do not eat meat are actually healthier, as is clearly evident in their lesser tendency to heart disease. 

We do not yet explained the increase in the risk of having a stroke, so further research is needed. 

They conclude that as long as vegetarians pay close attention to medical surveillance and taking nutritional supplements if necessary, they have no cause for concern.


Vegetarian diets and health

BMJ 2019; 366 doi: (Published 04 September 2019)Cite this as: BMJ 2019;366:l5272

Risks of ischaemic heart disease and stroke in meat eaters, fish eaters, and vegetarians over 18 years of follow-up: results from the prospective EPIC-Oxford study

BMJ 2019; 366 doi: (Published 04 September 2019)Cite this as: BMJ 2019;366:l4897