In light of the recent controversy around meat consumptio, we’ve decided to survey the latest data on meat and investigate the truth about the health risks of eating meat, especially red meat.
When considering the health effects of any food, it is important to ask: compared with what? Guidelines on meat consumption in cardiometabolic health have historically been based on minimally adjusted ecological comparisons.
An ecological comparison or study consists in measuring disease rates and exposures to a suspected cause, here meat, in different populations before their relation is examined. This type of study is appropriate only for initial investigation of a causal hypothesis.
Furthermore, the purported greater risk of cardiovascular disease (CVD) with meat lies in assumptions about the impact of isolated nutrient contents (eg, saturated fat, dietary cholesterol), rather than the matrix of fatty acids, proteins and micronutrients in the food.
However, modern nutritional evidence – including randomised trials, prospective cohort studies and randomised trials of multiple – not just single – biomarkers and risk factors supports relatively neutral effects of saturated fat and dietary cholesterol on CVD risk.
The essence of the issue seems to be more on the effects of other compounds in meats, such as heme iron, sodium, and other preservatives, as well as the level of processing/processing method of the product itself.
Unprocessed vs processed meat and CVD risk
Although some studies suggest a similar CVD risk for unprocessed red meat versus processed meats, many other studies and meta-analyses support a much stronger effect of processed meats, especially low-fat deli meats, on CVD.
Researchers believe that relationships between unprocessed red meat consumption and other non CVD-related outcomes (confounders) could explain part of the observed albeit modest associations of unprocessed meat with CVD.
Much of the association of processed meats with CVD can be explained by the blood pressure (BP)-raising effect of high levels of salt (about 400 per cent higher) in processed meats, and the subsequent effects of elevated BP on CVD endpoints, such as myocardial infarction (MI) or stroke.
Meat consumption and risk of type 2 diabetes
Recent findings point to evidence of both harm and benefit linked to meat consumption as it relates to the risk of type 2 diabetes. So what is the truth?
Interestingly, researchtends to show that both red and processed meats, regardless of fat content, are tied to a higher incidence of type 2 diabetes. However, there is approximately double the risk for processed meats than for unprocessed red meats.
Although this require further study, it is thought that the observed risk for type 2 diabetes may be linked to iron content and, to a lesser extent, to certain amino acids and lipid metabolites in meat.
Eating meat and staying healthy
Conventional diet guidelines that recommend to choose meats based on fat content for CVD prevention, i.e, to focus on selecting lower-fat cuts or lean meats, should be questioned according to newer evidence on dietary cholesterol.
Overall, the above findings suggest that it is fairly safe to consume small amounts of unprocessed red meats (eg, 1-2 servings per week) to obtain the RDAs in iron and zinc, while minimising or entirely avoiding processed (sodium and nitrates-rich) meats, like sausage, salami and low-fat deli meats.
