Diet and Nutrition Claims

We're often told to avoid red meat because too much is bad for our hearts. Indeed, research does suggest that a high-meat diet poses a health risk -- but the most established threat is cancer, not heart disease.

More than a dozen cohort studies have linked a high intake of red meat -- defined as beef, pork, lamb, or anything made from them, like hamburgers, sausage, or chili -- to an increased risk of colorectal cancer. For example, a European study of 478,000 men and women found that colorectal cancer was more common among those who consumed the most red meat (about 5.5 ounces or more a day) compared to those who ate the least (less than 1 ounce).

Research has also associated meat eating with other types of cancer, including lung, liver, and esophagus, though this evidence is less conclusive than that for colorectal cancer.

One possible culprit behind the meat-cancer connection is the type of iron (known as heme iron) in red meat. During digestion, it contributes to the formation of potentially cancer-causing substances in the gut known as N-nitroso compounds. Other suspects include chemicals known as heterocyclic amines (HCAs), which form when meat is cooked at high temperatures.

Scientists suspect that these same factors, along with red meat's relatively high levels of saturated fat may be responsible for any association with heart disease. But overall, the evidence linking red meat to heart disease is mixed. Some studies have found that those who eat more meat are at increased risk of heart disease. But when researchers pooled data from 20 studies involving 1.2 million people, they turned up no association.

These scientists did find that processed meats, which include bacon, ham, sausage, and hot dogs, were associated with a higher risk of both heart disease and diabetes. Other research has linked them to colon cancer as well. (Nitrates and nitrites, which are used to preserve, flavor, and color many processed meats, are suspected culprits.) One large study found that people who ate the most processed -- and red -- meat were slightly more likely to die prematurely.

None of this means you need to forgo meat completely. Just make it an occasional part of your diet and replace it whenever possible with vegetables, beans, fish, and chicken.

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