Langan Denhard and Claire Karlsson
Americans love red meat, but the World Health Organization’s October 2015 announcement that red meat is “probably carcinogenic” and processed meats are definitely cancer-causing may change that. Although the chance of you getting cancer from eating hot dogs, deli meats or bacon is small, the risk increases with the more you eat over your lifetime. Red and processed meats pose additional health risks that can increase the chance of death.
A study of over 170,000 men and women found that eating just one 3-ounce portion a day of pork, beef, or lamb may significantly increase your risk of dying early.1 And, unfortunately, a 3-ounce portion is much smaller than a typical American portion – it is about the size of a bar of soap. A double quarter pounder would be almost 3 days’ worth of meat. The research team, led by doctors An Pan and Frank Hu of Harvard University, tracked a group of 51,529 male health professionals and 121,700 female nurses for over 20 years, beginning in the 1980s. Men and women with a history of cardiovascular disease or cancer were excluded from the study.Every four years, the researchers sent the participants detailed surveys asking them about their dietary habits.The researcher kept track of deaths and determined the cause of death. By the end of the study in 2008, 23,926 of the participants had died, 5,910 of them due to cardiovascular disease and 9,464 due to cancer.
The participants were analyzed by comparing 5 groups that were designated according to their daily consumption of red meat.The group that consumed the lowest amount of meat—Group 1—ate on average a quarter serving of red meat a day, or about 2 standard-size servings (3 ounces) weekly. Group 3, the group in the middle, ate about one standard-size serving of red meat per day. Group 5, with the highest level of consumption, ate on average 2 servings a day—or 14 servings of red meat each week.
The people who ate the most red meat were also the people least likely to exercise regularly, mostly likely to smoke and drink, and had the highest body mass index—an index which uses height and weight to calculate if you are overweight.But by controlling for age, body mass index, level of physical activity, smoking status, and family history, the researchers were able to determine to what degree red meat alone played a role in people’s death. They found that the men who belonged to the one serving a day group—Group 3—were 20% more likely to have died in the course of the study than were the men in Group 1 who only ate a quarter serving every day. Meanwhile, the “hard core” red meat eaters in Group 5 were 37% more likely to have died than Group 1.
Eating larger or more servings of meat did not affect women as dramatically as it did men. Women in the moderate meat-eating group (Group 3) were 11% more likely to have died than women in Group 1, whereas Group 5 women were 24% more likely to have died than women in Group 1.
Combining the data for men and women, the researchers were able to evaluate the dangers of eating unprocessed and processed red meat: an additional serving per day of unprocessed red meat increased the risk of dying early by 13%. An additional serving per day of processed red meat (such as 2 slices of bacon, 1 hot dog, or 1 slice of lunch meat), increased the chances of dying prematurely by 20%.
A one-serving-per-day increase of unprocessed red meat increased the risk of dying from cardiovascular disease by 18%, and it increases the risk of dying from cancer by 10%. And if the red meat is processed, your risk of dying from cardiovascular disease goes up by 21% and your risk of dying from cancer by 16%.
The researchers determined that 9.3% of deaths in male participants and 7.6% in females would have been prevented had they limited themselves to an average of one half serving of red meat per day (1.5 ounces.)
The findings from this large and comprehensive study of 170,000 men and women on red meat and chances of death support the World Health Organization’s determination that eating processed meats is clearly linked with colon cancer. The WHO’s International Agency for Research on Cancer reviewed more than 800 studies on the risks of red meat and processed meat. They found that processed meats increase the chances of developing colon cancer and that red meat that is not processed is also likely to increase the chances of developing several different types of cancer, such as stomach, prostate and pancreatic cancer.2
What About Breast Cancer
You may have heard that a previous study of 44,231 women found that women who ate more red meat as adolescents were more likely to develop breast cancer before reaching menopause, but not more likely to develop post-menopausal breast cancer.3 The information about meat consumption in adolescence was based on their memories looking back as adults, however, not based on objectively measuring their food habits when they were adolescents. The researchers found that replacing one serving/day of red meat with one serving of poultry, fish, legumes, or nuts decreased the chances of developing premenopausal breast cancer by an average of 23%.
If by this point you’re considering cutting down on red meat, you may be wondering what to eat instead.The research team used substitution analysis to determine how much people could lower their risk of premature death by eating one serving per day of fish, poultry, nuts, legumes, low-fat dairy products, or whole grains instead of a daily serving of red meat.They found that for each serving consumed in place of one serving of red meat daily, the risk of premature death decreased as follows: 7% for fish, 14% for poultry, 19% for nuts, 10% for legumes, 10% for dairy, and 14% for whole grains. It is impossible to know why fish was not as beneficial as the other alternatives, but perhaps it is because the most popular fish meals in the U.S. tend to be tuna salad or fried fish, both of which have high fat content.
How worried should I be?
There is now well-established evidence that processed meats are a carcinogen – they can cause cancer. However not all carcinogens are equally dangerous. Smoking, for example, is much more likely to cause cancer than your breakfast bacon. But the latest research should encourage all of us to eat processed meat only rarely and to eat red meat in moderation, or less often.
Although meat is a popular protein source, it is not the healthiest one. Red meat tends to be higher in saturated fat, which raises cholesterol in the blood. High cholesterol levels can result in cardiovascular disease. While processed and unprocessed read meats are both high in saturated fat, the high sodium content of processed red meat makes it even more harmful. When the body gets more sodium than the kidneys can handle or can be excreted through urine, sodium begins to build up in the bloodstream. This makes it harder to pump blood through blood vessels, which increases the pressure on the arteries. Americans consume about 3400 mg of sodium day, on average—much more than the USDA’s recommended limit of 2300 mg a day. Processed red meats generally have four times the amount of sodium and 50% more preservatives than unprocessed red meats.4 You can read more about the differences between processed and unprocessed red meats here.
There isn’t a clear answer for why red and processed meats cause cancer, but studies suggest that a variety of high-temperature cooking methods, including grilling and barbecuing meat, can lead to the formation of cancer-causing substances. Since processed meats are often smoked or cured, that process also promotes abnormal cell-growth.5. A type of iron found in all red meats has been found to promote colon cancer, particularly in cured meats like salami.6 However, better research is needed to understand how different cooking methods and iron levels lead to greater risks for cancer.
Cutting Back on Red Meat
Giving up meat entirely would be tough for many, but the mounting evidence against regular meat consumption is hard to ignore.Try eating chicken or fish (but not fried!) as your protein source, rather than hamburgers, pork chops, or deli meats. Dr. Frank Hu, the lead author of the study, suggests eating unprocessed red meats no more than 3 times a week—that’s nine ounces of beef, lamb or pork over seven days.Bacon, hot dogs, bologna and other processed meats, although tasty, should only be eaten occasionally—at a baseball game or picnic.
Remember that a healthy diet combined with regular physical activity is the best way to improve the quality and length of your life! Check out our 10 easy steps to get your family eating healthy!
All articles on our website have been approved by Dr. Diana Zuckerman and other senior staff.
- An, Pan, Qi Sun, Adam M. Bernstein, Matthias B. Schulze, JoAnn E. Manson, Meir J. Stampfer, Walter C. Willett, and Frank B. Hu. “Red Meat Consumption and Mortality.”Archives of Internal Medicine(2012). Web. 15 Mar. 2012. ▲
- Bouvard, Véronique; Loomis, Dana; Guyton, Kathryn Z; Grosse, Yann; El Ghissassi, Fatiha; Benbrahim-Tallaa, Lamia; Guha, Neela; Mattock, Heidi; Straif, Kurt. (October 2015). “Carcinogenicity of consumption of red and processed meat”. The Lancet. DOI: href=”http://dx.doi.org/10.1016/S1470-2045(15)00444-1″>http://dx.doi.org/10.1016/S1470-2045(15)00444-1. ▲
- Farvid MS, Cho E, Chen WY, Eliassen AH, Willett WC. Adolescent meat intake and breast cancer risk. Int J Cancer. 2015 Apr 15;136(8):1909-20. doi: 10.1002/ijc.29218. Epub 2014 Oct 3. http://www.ncbi.nlm.nih.gov/pubmed/25220168 ▲
- Cole, Megan.“Are Processed Meats More Dangerous than Other Red Meats?Yes and No!”Center for Research.National Research Center for Women and Families.Web.3. Apr. 2012. ▲
- Tasevska, N., Sinha, R., Kipnis, V., Subar, A.F., Leitzmann, M.CF., Hollenbeck, A.R., Caporaso, N.E., Schatzkin, A., Cross, A.J. (June 2009). “A prospective study of meat, cooking methods, meat mutagens, heme iron, and lung cancer risks”. American Journal of Clinical Nutrition. 89(6)1884-1894. doi: 10.3945/ajcn.2008.27272Am J Clin Nutr ▲
- Santarelli, R.L., Pierre, F., Corpet, D.E., (2008). “Processed meat and colorectal cancer: a review of epidemiologic and experimental evidence”. Nutrition and Cancer. 60(2):131-44. doi: 10.1080/01635580701684872 ▲