Too Much Red Meat Ups Stroke Risk

Pam Harrison

August 23, 2012

August 23, 2012 — The atherogenic effects of consuming too much red meat have again been demonstrated by the largest meta-analysis to date showing that each increase in a single serving of fresh, processed, and total red meat consumption a day significantly increases the risk for total and ischemic stroke.

Joanna Kaluza, PhD, from Warsaw University of Life Sciences, in Warsaw, Poland, and colleagues from there and from the Karolinska Institute, in Stockholm, Sweden, found that the risk for total stroke increased by between 11% and 13% for each increase in a single serving of fresh, processed, and total red meat consumed per day.

Each daily increase in a single serving of fresh, processed, and total red meat consumption was also associated with a 12% to 15% increased risk for ischemic stroke.

In contrast, no significant association was observed between red meat consumption and risk for hemorrhagic stroke.

"Not all studies have shown a statistically significant association between red and processed meat consumption and risk of stroke. For example, a study in Japan observed no association," Susanna Larsson, PhD, from the Karolinska Institute, told Medscape Medical News. "So even though the associations were quite modest, results are still important because so many individuals consume red meat."

This study was published online July 31 in Stroke.

Not Limited to Stroke

According to investigators, clarifying the relationship between red meat consumption and stroke is relevant because of the high incidence of stroke around the world and its attendant morbidity and mortality.

A total of 6 prospective studies involving 10,630 stroke cases and 329,495 participants were included in the analysis. Four studies included data about stroke subtypes and involved 6420 cases of ischemic stroke and 1276 cases of hemorrhagic stroke.

As investigators note, 2 studies provided red meat consumption in grams per day, 3 in servings per day, and 1 in how often red meat was consumed per day.

For the purposes of the analysis, 1 serving equaled approximately 50 grams of processed meat a day, and 1 serving of fresh red and total red meat equaled 100 to 120 grams a day.

Red meat includes beef, pork, lamb, and veal.

Table. Relative Risk of Red Meat Consumption and Total Stroke Risk

  Relative Risk 95% Confidence Interval
Fresh red meat 1.11 1.03 - 1.20
Processed meat 1.13 1.03 - 1.24
Total red meat 1.11 1.06 - 1.16

 

"Stroke is only one of the diseases that [have] been associated with red and processed meat consumption," Dr. Larsson said.

"Red and processed meat consumption has also been associated with an increased risk of colorectal cancer, stomach cancer, and possibly other cancers, as well as myocardial infarction and type 2 diabetes. So the public health message is to reduce consumption of red meat, especially processed meats, and replace them with other protein-rich foods such as poultry, fish, and legumes," he added.

Public Unaware

Adam Bernstein, MD, PhD, from the Wellness Institute at Cleveland Clinic in Ohio, told Medscape Medical News that he seconded investigators' concerns that the public may not be aware of the increased health risks of consuming red meat, not only for the incidence of stroke but also for a number of cancers, diabetes, high blood pressure, heart failure, and premature death.

"There are a host of diseases associated with red meat consumption, and this study is another log in the fire, adding to the importance of reducing or eliminating red meat from the diet," he said.

In his own study, reported by Medscape Medical News in January of this year, Dr. Bernstein similarly found that higher consumption of both processed and unprocessed red meat is associated with higher risk for stroke, whereas poultry intake is associated with reduced risk.

Relative risks for total stroke identified by Bernstein and colleagues at 1.32 for each daily serving of processed meat and 1.16 for each daily serving of unprocessed red meat were very similar to results achieved on the current meta-analysis.

The relative risk reduction for total stroke, again identified by Bernstein and coworkers per single serving of poultry a day, was 0.77.

"It's not just the saturated fat content of red meat that contributes to stroke risk, it may also be the heme iron in red meat," Dr. Bernstein observed. "So simply using low-fat meat products may not confer a health benefit either."

The nitrates and nitrites found in processed meats in turn may play a role, as could high sodium content, which contributes to elevated blood pressure.

This research was supported by a grant from the Swedish Council for Working Life and Social Research. Dr. Larsson and Dr. Bernstein have disclosed no relevant financial relationships.

Stroke. Published online July 31, 2012.

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