Bacon has been the darling comfort food lately, with recipes abounding for bacon in everything possible including mayonnaise and ice cream. But you might want to hold that extra slice. A new Harvard analysis shows that one daily serving of processed red meat (a hot dog or two slices of bacon) increased overall mortality risk by 20%. One daily serving of unprocessed red meat (about the size of a deck of cards) increased risk of death by 13%.
The findings are based on two large ongoing studies from the Harvard School of Public Health: the Nurse’s Study of 83,644 women and the complementary Health Professionals Follow-up Study of 37,698 men. Since 1976 these studies have explored the links between diet, lifestyle, and health outcomes, questioning participants every four years about their diet and other health factors and investigating and tallying causes of death.
Yesterday an analysis of the results, Red Meat Consumption and Mortality, was published in a free, full-text online version through the Annals of Internal Medicine. The analysis considered the women’s diets from 1980-2008 and the men’s from 1986-2008.
Study participants who ate more meat also smoked more, drank more, weighed more, and were less active, but the analysis controlled for all those variables and more. The study revealed a striking relationship between the number of servings of red meat per day and the risk of death.
Among specific causes of death, an extra serving of red meat a day increased cardiovascular-related deaths by 18% (unprocessed meat) and 21% (processed meat). For cancer, the corresponding increases in death rate were 10% and 16%.
The authors hypothesize that some of the potentially harmful factors in red meat may be heme iron, saturated fat, nitrates, and carcinogins that are formed when meat is cooked at high temperatures. Extra sodium and nitrates may explain why processed meat is a higher risk factor than processed meat. There was a trend toward bacon and hot dogs being higher risk than other kinds of processed meat like sausage.
Red meat is the best source of iron, which can certainly be needed and beneficial. But excessive iron stores are known to the risk of fatal heart disease, especially in men.
Saturated fat is also known to increase the risk of heart disease and cancers. This study was not able to distinguish between eating lean and fatty kinds of meat, which is a difference worthy of further study.
Those who ate more red meat also ate fewer fruits, vegetables, and whole grains. So part of the story may be that meat-eaters were missing the protective factors that can be found in these foods, rather than simply being harmed by factors found in meat.
Each serving of total red meat replaced by a serving of an alternate protein source was associated with a lower risk of death: 7% less for fish, 14% for poultry, 19% for nuts, 10% for legumes, 10% for low-fat dairy products, and 14% for whole grains. The researchers estimated that 9.3% of deaths in men and 7.6% in women during the study period could have been prevented if all the participants had consumed less than half a serving a day of red meat.
“This study provides clear evidence that regular consumption of red meat, especially processed meat, contributes substantially to premature death,” said study author Frank Hu, MD. “On the other hand, choosing more healthful sources of protein in place of red meat can confer significant health benefits by reducing chronic disease morbidity and mortality.”
Another interesting finding of the study is that American meat consumption is declining, at least among the largely well-educated, mostly non-Hispanic white study population. Women’s red meat eating declined from around one serving to half a serving per day, while men’s portions declined slightly from .75 to .63 servings.
You’ll find lots of ideas for good meals not including red meat in the rest of this blog.