New research (1) has found that eating processed meats, such as sausages, bacon, processed hams etc, may be linked to an increased risk of heart disease and diabetes. However, the research did not find links between eating unprocessed red meatsand increased risk of disease. This research is the first systematic review and meta-analysis of the worldwide evidence for how eating unprocessed red meat and processed meat relates to risk of cardiovascular diseases and diabetes.
The researchers reviewed (1) 20 studies which included a total of over a million individuals and 23 889 coronary heart disease (CHD), 2280 stroke, and 10 797 diabetes cases. In the study red, unprocessed red meat was defined as any unprocessed meat from beef, lamb or pork, excluding poultry. Processed meat was defined as any meat preserved by smoking, curing or salting, or with the addition of chemical preservatives; examples include bacon, salami, sausages, hot dogs or processed deli or luncheon meats.
Red, unprocessed, meat intake was not associated with CHD or diabetes mellitus. Conversely, processed meat intake (50g serving per day) was associated with 42% higher risk of CHD and 19% higher risk of type 2 diabetes mellitus. Consumption of red and processed meat were not associated with stroke, but only 3 studies evaluated these relationships. There was no association for red, unprocessed, meats. The authors conclude that “These results highlight the need for better understanding of potential mechanisms of effects and for particular focus on processed meats for dietary and policy recommendations”.
In a press release (2) the lead study author, Renata Micha, said “Although most dietary guidelines recommend reducing meat consumption, prior individual studies have shown mixed results for relationships between meat consumption and cardiovascular diseases and diabetes,” “Most prior studies also did not separately consider the health effects of eating unprocessed red versus processed meats.”
The study does not prove that processed meats CAUSE health problems but studies like this are important in discovering potential risk factors for disease. The study did take into account other factors and adjusted for these risk factors. The authors did look at lifestyle factors and found that the lifestyle factors associated with eating unprocessed red meats and processed meats were similar, but only processed meats were linked to higher risk of disease. The lead study author also said (2) “When we looked at average nutrients in unprocessed red and processed meats eaten in the United States, we found that they contained similar average amounts of saturated fat and cholesterol. In contrast, processed meats contained, on average, 4 times more sodium and 50% more nitrate preservatives,” “This suggests that differences in salt and preservatives, rather than fats, might explain the higher risk of heart disease and diabetes seen with processed meats, but not with unprocessed red meats.”
Dietary sodium (salt) is known to increase blood pressure which is a strong risk factor for heart disease. The authors call for more research to look into the specific factors in processed meats that may be increasing the risk of disease. The author also recommended (2) “To lower risk of heart attacks and diabetes, people should consider which types of meats they are eating. Processed meats such as bacon, salami, sausages, hot dogs and processed deli meats may be the most important to avoid,” “Based on our findings, eating one serving per week or less would be associated with relatively small risk.”
Previously I have mentioned the World Cancer Research Fund (WCRF UK) a charity committed to cancer prevention. The WCRF recommend avoiding processed meats. Their recommendation is based on an expert report (3) published in 2007. Eating a diet which is low in any kind of processed or refined foods is a good idea for health. A balanced diet based on unprocessed meats and fish, unrefined/unprocessed carbohydrates and rich in vegetables and fruits is a good starting point for anyone wanting to eat healthfully.
(1)Micha R et al. 2010. Red and Processed Meat Consumption and Risk of Incident Coronary Heart Disease, Stroke, and Diabetes Mellitus. A Systematic Review and Meta-Analysis. Circulation. Published online before print May 17. DOI: 10.1161/CIRCULATIONAHA.109.924977
(2)Press release. Harvard School of Public Health (2010, May 17). Eating processed meats, but not unprocessed red meats, may raise risk of heart disease and diabetes, study finds. ScienceDaily. Retrieved May 18, 2010, from http://www.sciencedaily.com /releases/2010/05/100517161130.htm
(3) WCRF/AICR. 2007. Food, nutrition, physical activity, and the prevention of cancer: a global perspective. Washington DC: AICR, 2007.
Written by Ani Kowal
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