Although it is commonly known that meat products are not necessarily healthful when consumed in large quantities, for a long time researchers had not confirmed the precise link between red meat and mortality through a large-scale study over a significant period.

A 2012 study published in Archives of Internal Medicine, “Red Meat Consumption and Mortality,” changes the research picture. Conducted over a 22-year period with a pool of 121,342 individuals, the study — from researchers at Harvard Medical School, Harvard School of Public Health, Wellness Institute of the Cleveland Clinic and the German Institute of Human Nutrition — looked at how increasing meat consumption by one serving size (3 oz. or roughly one small beef patty) a day contributed to the chances of mortality. The study subjects were all American health professionals; analyzing such a group minimizes the chances that external factors such as diminished access to health care or lower education levels could skew the results.

The study’s findings include:

• An additional daily serving size of of red meat resulted in a 12% greater risk overall of mortality; increased red meat consumption was associated with elevated risk of cardiovascular disease and cancer. The increased risk of mortality was 13% for unprocessed red meat and 20% for processed red meat.
• If red meat intake was reduced to half a serving size a day, there would be 9.3% fewer deaths in male populations and 7.6% fewer deaths in female populations. Cardiovascular-related deaths would drop by 12.2% in men and 8.6% in women.
• The researchers found a high correlation between red meat eaters and smoking, alcohol consumption, high body mass index and reduced physical activity. Even when they controlled for these variables, however, red meat eaters still faced higher risk of mortality.
• There were no significant statistical differences between specific red meat food items, except the consumption of bacon and hot dogs tended to result in higher risk.
• The substitution of one serving of red meat for one serving of fish resulted in a 7% reduced rate of mortality; likewise, the reduction rate was 14% for chicken, 19% for nuts, 10% for vegetables, 10% for low-fat dairy products and 14% for whole grains.

The researchers suggest several theories for the correlation of red meat intake and higher mortality rate, including sodium content; the presence of nitrites and nitrates (used in meat preservation); and high levels of heme iron. Because most of the study’s participants were white, the study suggests further research into the impact of a red-meat-heavy diet on Hispanic or black populations.

A 2011 study, “Changes in Diet and Lifestyle and Long-Term Weight Gain in Women and Men,” published in The New England Journal of Medicine. provides additional insight into the relationship between dietary practices and body mass. The study notes: “For each of the following, an increase of one serving per day resulted in specific weight gains over a four-year period: french fries (3.35 pounds); potato chips (1.69 pounds); boiled, baked, or mashed potatoes (0.57 pounds); sugar-sweetened beverages (1 pound); unprocessed red meats (0.95 pounds); processed meats (0.93 pounds); refined grains (0.39 pounds); and sweets and desserts (0.41 pounds).”

Related research: A variety of studies are also focusing on the environmental impact of red meat production, which generally requires a substantial amount of grain for the livestock. See “Impact of a Reduced Red and Processed Meat Dietary Pattern on Disease Risks and Greenhouse Gas Emissions in the U.K.”; the United Nations report “Livestock’s Long Shadow”; and the 2012 PNAS study “Global Changes in Diets and the Consequences for Land Requirements for Food.”

Tags: nutrition, cancer