The connection between eating large amounts of red or processed meat and certain diseases is well-known, but a new study suggests that consuming even a small amount of these foods could be risky.
The world is eating more meat. The global consumption of meat and poultry has increased in both developed and developing countries over the past 50 years, according to the Food and Agriculture Organization of the United Nations.
Red meat is the most popular type of meat in the United States. Processed meat that has undergone curing, smoking, or salting to alter its flavor makes up 22 percent of U.S. meat consumption, according to a 2011 study.
Previous studies have examined the effects of eating moderate-to-high amounts of meat on mortality. However, the impact of consuming a small amount has remained largely untested.
Finding the perfect sample
Researchers at Loma Linda University Health in California aimed to address this imbalance in a new study.
"We wanted to take a closer look at the association of low intakes of red and processed meat with all-cause, cardiovascular diseases, and cancer mortality compared to those who didn't eat meat at all," states lead author Saeed Mastour Alshahrani.
The team's findings suggest that eating small amounts of red and processed meat could increase a person's risk of death.
The researchers used data from people who took part in the Adventist Health Study-2 (AHS-2). Between 2002 and 2007, this cohort study recruited close to 96,000 Seventh-day Adventists living in the U.S. and Canada.
Adventists are an interesting group for scientists looking into factors relating to the diet. About half of these believers are vegetarian, and those who do choose to eat meat consume very little of it.
To see whether meat consumption had any effect on mortality, researchers analyzed two factors. The first was the cause of death of more than 7,900 Adventists over an 11-year period. The second was a dietary assessment of the same individuals using food frequency questionnaires.
Higher risk of death
The researchers noted that meat intake was low. Among the people who reported consuming meat, 90 percent ate 2 ounces or less of red meat per day.
When they evaluated the deaths, the investigators found that cardiovascular disease was responsible for almost 2,600 of them, while more than 1,800 deaths related to cancer.
The results, which feature in the journal Nutrients, showed that there was an association between the consumption of a combination of red and processed meats and a higher risk of both total and cardiovascular disease deaths. Processed meat alone did not show a similar trend.
Certain groups appeared to be more susceptible to specific meat types. For example, unprocessed red meat was "significantly" related to a risk of all-cause mortality for white people but not for black people. When the researchers looked specifically at the risk of cardiovascular disease mortality, they noted that this was only significant among women and black people.
Black people and women also had an increased risk of all-cause mortality from eating processed meat. However, the team only identified a link between processed meat consumption and cardiovascular disease in women.
The researchers did not report any significant findings relating to cancer, but they noted that other studies have found evidence of a relationship between meat intake and this disease. As a result, they suggest that this association may only become apparent with higher meat consumption.
A new conclusion
The authors of the new study believe that their work supports previous conclusions. "Our findings give additional weight to the evidence already suggesting that eating red and processed meat may negatively impact health and lifespan," comments Michael Orlich, Ph.D., co-author of the study and co-director of AHS-2.
The study also shows something new by demonstrating that eating even a small amount of red and processed meat could be worse for health than eating none.
The study has both strengths and limitations. Researchers adjusted the results for various factors, including obesity, physical activity, and low intake of fruit and vegetables.
To strengthen the findings, they also took into account specific dietary factors, such as intake of dairy, whole grains, and legumes. It also helped that relatively few of the participants smoked or drank alcohol.
However, the study relied on questionnaires, which could cast doubt over the results because people may not recall consuming food that they eat very little of or consume irregularly.
More research will be necessary to support the findings of this study. It is also still unclear precisely what causes red and processed meat to lead to adverse health outcomes.