In a nutshell: It depends on the type of red meat.
The Evidence
Micha, R., Wallace, S. K., & Mozaffarian, D. (2010). Red and processed meat consumption and risk of incident coronary heart disease, stroke, and diabetes mellitus: A systematic review and meta-analysis. Circulation, 121, 2271- 2283. DOI: 10.1161/CIRCULATIONAHA.109.924977
What did the meta-analysis look into?
This meta-analysis investigated whether eating red meat (e.g., beef, lamb, pork, game), processed red meat (meat that is smoked, salted, cured and/or added chemical preservatives, such as bacon, salami, hams, sausages), and total red meat (all red and processed meats) increases the risk of Coronary Heart Disease (CHD), stroke, and type 2 diabetes. The meta-analysis synthesized evidence from 20 studies, including a total of 1 218 380 people from the United States, Europe, Asia, and Australia. Of these, 23 889 had CHD, 2280 had had experienced at least one stroke, and 10 797 had type 2 diabetes.
The meta-analysis also investigated whether several factors affected the relationship between the meat consumption and risk of disease, including:
1. Number of meat servings per week (serving sizes were defined as 100 grams for red meat and 50 grams for processed meat)
2. Location of participants (USA, Europe, Asia, Australia)
3. Socio-demographic characteristics of participants (e.g., education, income)
4. Other participant risk-factors for disease or special diets (e.g., current smoking, being overweight, family history of chronic disease, higher calorie intake)
What did the evidence suggest for CHD?
Red meat consumption was not associated with CHD, but each daily serving of processed meat was associated with 42% higher risk of CHD. Consumption of ‘total meat’ was associated with a trend towards higher CHD risk. None of the additional 4 factors played a role for CHD.
What did the evidence suggest for type 2 diabetes?
Red meat consumption was not associated with type 2 diabetes. However, each serving of daily processed meat was associated with 19% higher risk of type 2 diabetes, and the risk was even higher for US participants. Each daily serving of total meat was associated with 12% higher risk of type 2 diabetes.
What did the evidence suggest for stroke?
Red or processed meat consumption was not associated with higher risk for stroke, but each daily serving of ‘total meat’ was associated with 24% higher risk.
The take-home message
Unprocessed red meat consumption does not appear to be associated with higher risk for CHD, stroke, or type 2 diabetes, but processed and ‘total’ meat consumption appears to be associated, especially if the consumption is on a daily basis. The meta-analysis proposed that the high amounts of salt and nitrate (and other chemical) preservatives in processed meats could be the culprits behind the higher risk of CHD, stroke, and type 2 diabetes. Broadly speaking, consumption of red meat appears to be safe, as long as it is not processed and not consumed daily.
