New Study Implicates Red Meat in Greater Stroke Risk for Women

Alarm bells sounded for women's health advocates. In a new study of 30,000 Swedish women, it was found that women who eat lots of red meat may be putting themselves at increased risk of stroke. In this particular study, researchers also discovered that the top 10% of women (who ate more than 3 ounces of red meat on a daily basis) were 42% more likely to suffer a stroke from blocked blood flow in the brain compared to other women (who consumed less than an ounce of red meat daily.)

What does this mean for the rest of us? This may mean that women with diets heavy in red meat may need to adjust their routines, given the increased incidence of some cancers, heart disease, and high blood pressure. For the 153,000,000 women who live in the United States, these and other studies will provide a much-needed wake up call on the link between dietary choices and stroke risk. Hopefully, this information will spur more research into women's health.

About the Study on Swedish Women

It's interesting how they approached the study of the Swedish women. Dr. Susanna Larsson (from the Karolinska Institute in Stockholm) and her research team examined 34,670 women 39 to 73 years old. All the women were free of cardiovascular disease and cancer at the beginning of the 1997 study.

After tracking these women for 10 years, researchers found that 1,680 of the women (4 percent) had a stroke. In most cases, it was stroke "cerebral infarction" where blood is blocked from going to the brain. Strokes in the remaining women were attributed to bleeding in the brain, or unspecified causes.

The study was structured in an interesting way to shed light on the amount of red meat consumed and its relationship to stroke risk. Researchers divided the women into five groups based on how much red meat they reported eating. Researchers found that those in the top fifth, who ate at least 3 ounces of meat per day, had a 22 percent greater risk of cerebral infarction than women in the bottom fifth of the study who consumed less than 1.3 ounces each day.

The Evidence on Processed Meat

Women who at processed meat were also found to be at risk for stroke. Women who ate the most processed meat (about 1.5 ounces, a day) were at 24 percent greater risk of this type of stroke than women who consumed the least (less than half an ounce each day). Interestingly, researchers found no link between consumption of red or processed meat and risk of other types of stroke, nor was there any causal relationship between fresh meat consumption or poultry consumption and any type of stroke.

The study also produced counter-intuitive results. The consumption of red meat increased stroke risk in non-smokers, but not in smokers. In women who didn't have diabetes, but not in women with diabetes. Surprisingly, for non-smokers and non-diabetics in the top tenth of red meat consumption, the risk of cerebral infarction was 68 percent greater.

The Suggested Link Between Red Meat, Processed Meat and Stroke Risk

Researchers suggest several things could explain the link between red meat and processed meat and stroke risk. Both red meat and processed meat promote high blood pressure, the main cause of stroke. It may be that the iron contained in red meats accelerates the production of tissue-damaging free radicals. Finally, processed meats are very high in sodium, which can increase blood pressure, another factor in promoting stroke. More research will likely shed additional light on these and other factors.

RESOURCES

Eating lots of red meat ups women's stroke risk
Reuters Health (Dec 31, 2010)

Guide to Lowering Your Blood Pressure
Diseases and Conditions, High Blood Pressure
National Heart Lung and Blood Institute of the National Institutes of Health

National Institutes of Health
www.nih.gov

Mayo Clinic, Rochester, Minnesota
www.mayoclinic.org

Home Blood Pressure Measurement
A Systematic Review
Journal of American College of Cardiology, 2005; 46:743-751