Meat and Cancer

by Jacob Franek

How is meat linked to cancer?

The whole idea that meat might cause cancer came from several large European population studies back in the early 1990s showing that vegetarians were almost half as likely to develop cancer as meat eaters when controlling for other diet and lifestyle factors. Since then, studies have continued to investigate the link. While some of the evidence seems compelling, what exactly is it about meat that might be dangerous? Although it’s not entirely clear, there are a number of hypotheses:

• Meat lacks fiber, antioxidants, phytochemicals, and other helpful nutrients that have shown to be protective against cancers.
• Many meats are high in fat and other animal products that increase hormone production, thus increasing the risk of hormone-related cancers such as breast or prostate cancer.
• High-protein diets have been linked to cancer. Meats are high in protein, and protein is broken down to ammonia, which may be carcinogenic in humans.
• Cooking meats at high temperatures forms carcinogenic compounds such as heterocyclic amines (HCA) and polycyclic aromatic hydrocarbons (PAH). These compounds have proven carcinogenic in mice, rats and nonhuman primates in lab studies.
• Salt-preserved, smoked and other preserved meats contain N-nitroso compounds (NOCs) that are potentially carcinogenic to humans.

Which meats are of concern?

While many studies have identified general meat intake as a risk factor for cancer, specifically the red meats like beef, lamb, pork, veal, and processed meats (meats preserved by salting, drying, smoking or curing), appear to put consumers at highest risk and have been the subject of most studies.

However, it’s not only the type of meat that is a cause for concern, but also the way in which it’s prepared. The cooking method, temperature and time all influence how carcinogenic certain meats are. Meats cooked at very high temperatures by frying, broiling and barbecuing produce the largest amount of HCAs, whereas oven roasting and baking are done at lower temperatures and thus form less HCAs. Stewing, boiling or poaching are done at such a low temperature that dangerous chemicals do not form.

Lastly, cooking for longer periods of time (for example, making a steak that’s well-done,) will cause more carcinogenic compounds to be formed than cooking for shorter periods of time, for example, making a steak that’s “bloody.” Just remember that undercooking meats can be dangerous, leading to food poisoning or other infection.

Are organic meats safer than conventional industrial meats?

Organic meats come from animals that are grown without growth additives or antibiotics. Whether organic meats are safer than nonorganic meats has never really been proven. Generally speaking, the amount of steroidal hormones found in meat is miniscule compared to those amounts that are known to increase the risk of cancer. The FDA even argues that leftover residues of growth additives in meat, specifically beef, are negligible in comparison to natural levels in both cows and humans.

To err on the side of caution, pregnant women and prepubescent children may want to avoid inorganic meats. Similarly, individuals may want to buy rBGH-free or certified organic milk and dairy products. rBGH is a growth hormone that some say causes cancer, although this has been largely disputed. More importantly, the use of antibiotics in animals increases the amount of antibiotic-resistant bacteria in the environment, which can have long-term consequences on human health in the future.

Do hotdogs cause childhood leukemia?

Back in 1994, several studies implicated hot dogs in raising the risk of childhood leukemia. While the results of the most recent study, the Northern California Childhood Leukemia Study (NCCLS), showed no increased risk, parents may choose to have their children avoid nitrate-containing hot dogs just to be safe. Nitrates are used as preservatives in many processed meats, including bacon, and lead to the formation of those potentially carcinogenic N-nitroso compounds (NOCs).

What types of cancers are linked to meat?

Colorectal cancer has been studied most extensively and linked most conclusively to both red and processed meats. Consumption of these meats seems to cause a modest increase in risk of colorectal cancer. Men who eat red meat frequently also appear to have a higher risk of prostate cancer. Lastly, frequent consumption of red meat may raise the risk of breast cancer in women. Aside from these three, various other cancers including stomach, pancreatic, kidney, and esophageal have been linked to consumption of meat (although not as consistently).

How can I reduce my risk?

The National Cancer Institute provides some recommendations to reduce exposure to HCAs in meat:

• Vary methods of cooking meats.
• Microwave meats more often, especially before frying, broiling or barbecuing.
• Refrain from making gravy from meat drippings (a substantial source of HCAs).
  

Aside from that, to reduce the risk of cancer from meat one should:

• Increase consumption of fruits, vegetables and fish while limiting consumption of red and processed meats.
• Select meats that are lean, low-fat or fat-free.
  

blame the bbq

“Everything causes cancer” -- a common belief that many subscribe to. While from a cynical point of view this may hold some truth, it’s no reason to avoid common sense and practice unhealthy eating habits. Instead, practice the art of moderation. It might be impossible for you to avoid meat, and it’s understandable because barbecued meat is, well... divine. However, try to vary your food sources. After all, variety is the spice of life.