Meat Linked to Prostate Cancer

Eating large amounts of red and processed meats may be linked to an increased risk of prostate cancer, researchers report in the American Journal of Epidemiology.

The authors followed 175,343 men in the United States who were 50-71 years old from 1995 until 2003. They recorded the participants’ meat consumption, including the type of meat they ate and how they cooked it, and monitored their iron levels, nitrite/nitrate intake and the number of prostate cancer diagnoses.

By the end of the study, 10,313 developed prostate cancer, of which 419 died.

After adjusting for various factors known to increase the risk of prostate cancer, the authors found that men who ate the most red meat were 12 percent more likely to develop prostate cancer and 33 percent more likely to develop advanced prostate cancer than those who ate the least amount.

Processed meat was also linked to a higher risk of prostate cancer. However, the authors noted that red processed meats (like hot dogs and bacon) were linked to a greater cancer risk than white processed meats (like turkey sandwich meat).

Grilling was the only cooking method that was linked to an increased risk of prostate cancer. It has been suggested that cancer risk may be increased by compounds called heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), which are formed when meat (especially red meat) is cooked at high temperatures. When heated, the amino acids, sugars and creatinine are converted into HCAs and PAHs, which have been linked to various cancers, including stomach, colorectal, pancreatic and breast cancers, in humans.

Nitrate intake was also correlated with an increased risk of the disease. Nitrates are preservatives that are added to processed and cured meats such as cold cuts and bacon. The preservatives have been associated with cancer-causing chemicals called nitrosamines.

This study supports growing evidence that too much meat may be unhealthy. Earlier studies suggest that red or processed meat may increase the risk of colon cancer and death (particularly from cancer and heart disease) and may be linked to age-related macular degeneration. Red meat also contains high amounts of saturated fats, which have been shown to increase the risk of heart disease.

Some other dietary changes may help reduce the risk of prostate cancer. For instance, eating fewer dairy products that are high in fat (like ice cream, cheese and sour cream) may be beneficial. Also, cruciferous vegetables (such as broccoli, cabbage and cauliflower) have been reported to contain cancer-fighting phytochemicals that may decrease the chances of developing prostate cancer.

The American Urological Association (AUA) encourages men who are in good health to have annual PSA testing starting at age 50, or at age 40 if they are in high-risk groups, such as African American men or those with histories of the disease. For more information on prostate cancer screening and prevention, please visit Natural Standard's Medical Conditions database.

For more information about integrative therapies for prostate cancer, please visit Natural Standard's Comparative Effectiveness database.

Comments

[Nancy Morrow, MS, CN]

Is it really the red meat that is causing the increase in prostate cancer? Cows who are fed diets of grain (corn) have higher arachadonic acid levels. When cows are fed their natural diets of grass, they have fatty-acid profiles similar to salmon! I would love to see a study comparison of grass-fed beef eaters to factory-farmed meat eaters.

[Grace Caulfield]

Nitrates should be consumed as little as possible. They are converted to nitrites by our body, and those are the more dangerous compounds. They don’t allow the blood to carry enough oxygen, and therefore, results in oxygen deficiency.

[URA]

Hate to add to the scare, but found another eye-opening study on the topic. A case-control study was conducted in Uruguay at 11 cancer sites for 8 years. The authors investigated the correlation between meat consumption and digestive tract cancers as well as others. The results were not encouraging. High intake of beef and lamb meat increased the chances of cancer of the oral cavity and pharynx, esophagus, larynx, stomach, colorectum, lungs, breasts, prostate, bladder, and kidneys. Processed meat showed similar results.

I am wondering what constitutes ‘high intake’? Are there any data available in regard to recommended doses for red meat? I don’t consume much but would not want to completely give up an occasional steak and cheese.

[Grace Caulfield]

It is so important for men to get screened, as men age their risk of prostate cancer increases. They should know their family histories, as this may put some men at increased risk. Men should also know that if they are taking any kind of testosterone/steroid therapy, which also increases their risk.

[www.facebook.com/profile.php?id=100000183076410]

It's unlikely that nitrate is a problem given that leafy greens are high in nitrate
http://www.sciencedaily.com/releases/2009/08/090820175859.htm

[Sk]

I wonder how clear the correlation between eating red meat and prostate cancer can be. The study was performed in an age group of men that is already at a higher risk of prostate cancer, thus it would be difficult to determine how much that factored in the findings of this study.

[Ouch]

It is not surprising to hear that high consumption of meats can be linked to any cancer, but 12% and 33% sounds like very high rates. Burnt B.B.Q meats on the grill are the risky ones. They form carcinogens when cooked at high temperatures — which mainly involve cellular mutations and tumor cell growth. It is same theory for cruciferous vegetables; that may reduce the chance of cancers, and it can be applied to any cancer.

[dan]

Considering that this is a fairly large study and it followed the men through many years, I think it’s important to take the results seriously. However, I am not surprised that meat has been linked to prostate cancer, especially processed meats, such as cold cuts and bacon, since I have heard of the high nitrate intake being correlated with an increased risk of various cancers.

I am surprised that grilling these meats was associated with a higher risk since most of the time “grilled” options are considered healthier than other ways of cooking.

I don’t think this article should scare men away from meat in general, but just send the message to limit the intake of processed meats and opt for more “white” meat than “red” meat, which is probably a good idea concerning numerous health outcomes.

[PJ]

Most men are already at a higher risk of developing prostate cancer as they age. Many men will die of old age, and prostate cancer will be found coincidentally upon autopsy. This study was conducted in a high-risk population, so I wonder if it was that red meat consumption put them at a higher risk for prostate cancer or just the fact that researchers were looking for it.

[Tim]

Cruciferous vegetables like broccoli, cauliflower and cabbage may decrease the risk of getting prostate cancer. What is the proposed mechanism behind this?

[Pia]

Somebody told me that leafy green vegetables are rich in nitrates, but there are so many good properties of these vegetables that I would hope they outweigh the bad from nitrates.

[Grace Caulfield]

Red meat is not only linked to prostate cancer, but also colon cancer. According to the American Cancer Society, people who eat 3 or more ounces of red meat per day are 30-40% more likely to develop cancer in the lower part of the colon.

[DF]

I was interested to see Nancy Morrow mention salmon. An April 2009 study by V. Fradet found that men whose diets included the highest amount of omega-3 fatty acids were 63 percent less likely to develop aggressive prostate cancer compared to men whose diets included the lowest amount of these healthy fats. Besides fish and cruciferous vegetables, cooked tomatoes may also reduce prostate cancer risk. And green tea has shown promise as well.

[Mike]

It appears that lifestyle changes, diet and exercise may be the most important things for men to do to try to prevent prostate cancer. High-fat dairy products should be eaten in moderation. Cruciferous vegetables, such as broccoli, cabbage, and cauliflower, should be increased. Also, foods that are high in antioxidants are thought to contain cancer-fighting phytochemicals, so increasing things like berries, grapes, tomatoes, carrots and peppers, may help prevent prostate cancer.

[karina]

I would like to comment on the following comment made in the article "...eating fewer dairy products may be beneficial." Recently, I started listening to "The China Study" book on CD, and the author stresses the importance of completely cutting dairy out of the diet, for everyone. This is a lengthy and rather dense book, but it offers fascinating details about the connection between nutrition and heart disease, diabetes and cancer. The author produced more than 8,000 statistically significant associations between various dietary factors and disease, including dairy and meat-based protein. The author, Dr. Campbell writes, "People who ate the most animal-based foods got the most chronic disease... People who ate the most plant-based foods were the healthiest and tended to avoid chronic disease. These results simply could not be ignored."

Just as the article on Natural Standard's blog suggests, the book maintains that the high-protein diets were the ones most likely to cause cancer. The book's major thesis is that people could prevent or cure most diseases, such as heart disease, cancer, diabetes and autoimmune disorders, by eating a plant-based diet rich in whole foods. This type of diet drastically reduces protein intake and does not include meat or dairy products.

I completely agree, and growing up in a family of 100% vegetarians, I have experienced this first hand.

[Sa]

I wonder how strong the correlation is between red meat consumption and the study population. The study population is already at high risk for developing prostate cancer. It would be interesting to see how eating red meat affects a younger group of men.

[TMP]

This isn’t surprising. Red meat has been linked to several types of cancer, not to mention hyperlipidemia and hypertension. The Mediterranean diet limits exposure to red meat with great success for hyperlipidemia and hypertension. The study didn’t mention if organic meats were used. I wonder if this would change the outcome, especially, if a cooking technique different from grilling was used instead. This study just confirms my feelings toward limiting red meat intake.

[Nina]

This article provides great awareness to carcinogenic compounds, such as heterocyclic amines (HCAs), polycyclic aromatic hydrocarbons (PAHs) and nitroso compounds. It's challenging to assess the intake of these dangerous dietary carcinogens since there seem to be no general guidelines of safe cooking or food composition databases of nitroso compounds. A good recommendation at this point may be to avoid cured and charbroiled meats.

[HJ]

On a related note, good scientific evidence supports the use of selenium as a way to help reduce risk of prostate cancer, according to the Natural Standard monograph on prostate cancer. Selenium is a trace mineral found in soil, water and some foods (like garlic, ginseng, grains, radish, sunflower seeds, walnuts, raisins, shellfish and fresh-water and salt-water fish). It decreases angiogenesis (growth of new blood vessels in tumors) and increases antioxidant effects, including cancer cell apoptosis (cell death).

[T.b.]

Nitrates are derived from the soil. Humans ingest nitrates when they eat plants that were grown in the soil. Therefore, one cannot limit the amount of nitrates to be ingested because our only source of food is from plants that use non-organic nitrogen, such as nitrates, from the soil. In addition, if the body is in homeostasis most of the time, we eliminate nitrogen and ammonia all the time through defecation, urination, perspiration, etc. So the question of nitrate poisoning is effaceable because the body automatically knows the amount it needs and shoots out the rest.

[Sweet banana]

It is noted that too much red meat consumption engenders aggression in males as a result of the animals of which the meats are derived from. Aggressive behaviors impact the liver, often changing its radiation and energy. The liver also is a sister to the pancreas. When it is malfunctioning, its effect is visible on the pancreas too. It will be interesting to observe the psychological conditions of these men: do they often feel irritated and vent off in attack after a big meal full of red meat? This will be a study worth cross referencing.

[EH]

Given the large sample size of this study, all men should undoubtedly be alarmed and aware of not consuming an excess amount of red processed meat. They should replace it with fresh white meat or seafood.

Besides cruciferous vegetables that were mentioned in this report, scientific studies have also demonstrated that an increased intake of tomato products among men is associated with a reduced risk of prostate cancer, in particular due to the carotenoid lycopene present in tomatoes. Lycopene in processed products, such as tomato sauce or ketchup, are absorbed into the body more efficiently. Adding some fat in the same meal can further enhance its absorption (e.g. tomato sauce with cheese on pizza or a little olive oil in spaghetti sauce).

[Yra]

According to the Natural Cancer Institute, other dietary factors that increase prostate cancer risk include fat, vitamin E, lycopene, dairy products/calcium/vitamin D and selenium. Phytoestrogens, on the other hand, may play a role in prevention. Phytoestrogens are found in significant amounts in soy products that are consumed in large amounts by Southeast Asian men who have the lowest incidence of prostate cancer. Other main risk factors include age and family history.

[Sam]

I wonder how much the study population affects the results. It would be interesting to see whether or not this is a confounding factor.

[jaka]

For anyone interested in overhauling their diet after reading this article, a good thought is to consider the Mediterranean diet. There is a webinar posted and a more recent blog about the fundamentals, but the diet basically involves eating as many whole foods as possible and limiting red meat to a once-monthly intake. Protein should primarily come from plant and lean animal sources and animal fats (such as butter) should be replaced with olive oil.

This diet has been shown to be heart healthy and is a complete lifestyle change compared with a simple fad diet.