A substantial piece of British research has examined the possible correlation between different types of diet and health risks. The results also revealed a higher likelihood of stroke among vegetarians and vegans compared with those who eat meat and fish.
That we should all eat less meat is no longer a debatable question: studies and research have shown that reducing meat consumption is good for the environment and for our health (especially when it comes to processed red meat). Many people have even eliminated it entirely from their diet for health or ethical reasons, adopting a vegetarian or vegan diet. Recently, however, on the subject of the correlation between diet and health, the results of a study published last September by the British Medical Journal have opened up new avenues for reflection and investigation.
Between 1993 and 2001, the nutritional epidemiology researchers who carried out the study recruited 48,188 British people, both women and men, and followed them for 18 years, dividing the group into three categories: "meat eaters", i.e. people who ate meat, "fish eaters", people who consumed fish but not meat, and "vegetarians", meaning vegetarians and vegans. For each group, the research then examined the likelihood of experiencing cardiovascular events such as stroke and ischaemia. The result? The research found that vegetarians and fish-eaters were less likely to have an ischaemic attack than those who also ate meat (−20 per cent and −13 per cent respectively), but that, at the same time, vegetarians and vegans were more likely to suffer a stroke (+20 per cent) compared with those who included meat in their diet. Put another way, those who ate meat were more likely to experience cardiac ischaemia than vegetarians/vegans or fish-eaters, but less likely to have a stroke than those who ate only fish (in this case with statistically non-significant data) and — in a statistically significant way — than those following a vegetarian/vegan diet.
"Because the study is observational and, to date, little is known about the overall dietary habits of the participants in the analysis, it is certainly too early to formulate concrete hypotheses," explains Dr Michela C. Speciani, a surgeon specialising in applied nutrition and author of the book Incredibilmente in forma – sport e nutrizione per stare bene. "It remains interesting nonetheless to note that the statistically significant risk in the study was identified in the diet 'without meat or fish', particularly for haemorrhagic stroke, in which a significant restriction of protein in the diet may play a role. This does not mean that a diet without meat or fish cannot contain the right amount of protein, but that reaching one's target may in these cases be more demanding or require greater attention. In a similar way, the restriction of certain specific fatty acids or even of cholesterol intake could also play a part. No certainties here, then, but some interesting avenues to bear in mind and explore through further studies."
Within the study, the researchers also highlighted the possibility that the risk of ischaemia in "meat-eaters" was influenced by other factors as well, such as low levels of physical activity, consumption of trans fats or ultra-processed foods, with consequent weight gain, high cholesterol, diabetes, high blood pressure. In the case of stroke in vegetarians and vegans, on the other hand, the probabilities remained unchanged even regardless of blood pressure, body mass index, cholesterol and diabetes.
"The data confirms the overall value of paying general attention to lifestyle and diet. The recommendation to broadly reduce simple sugars and trans fats remains strong and clear, as does the advice to increase fibre consumption (fruit, vegetables, wholegrains, legumes), unsaturated fats (such as those typically of plant origin) and antioxidants (fresh and seasonal fruit and vegetables, oilseeds, etc.). Equally important is the recommendation of a balanced diet, with particular reference to the well-known 'Harvard Plate', one that contains at least sufficient protein as well as essential micronutrients. This applies both to those who choose the vegetarian path and to those who also consume meat or fish," the doctor continues. On the subject of meat, it is worth recalling that, to date, the WHO has classified processed meat as a carcinogen and red meat only as a "probable carcinogen" (in the category where the presence of bias cannot yet be ruled out). It is equally important to note that, in the observational study we are discussing, including at least some fish in the diet was associated with a lower risk of cardiac ischaemia compared with those who "also ate meat", but also with a risk of stroke not significantly different from that of the same group."
