Meat And Cancer? What’s the Connection?

Assessing Your Risk

Recent news from the WHO (World Health Organization) correlating meat consumption with cancer development elicited strong reactions from the public and media. Although this information isn’t new, arising from research conducted over the past few decades, the warning seemed particularly strong this time. For many Americans the news was a blow to the stomach, literally.  And as predicted, the meat industry fought back citing conflicting evidence in order to ensure Americans continue to support their bottom line.

Although conflicting evidence exists, when taken as a whole, the body of evidence demonstrates a strong correlation between the consumption of processed meats and two types of cancer: colorectal and stomach. The correlation between red meat and cancer development was less definitive but still present. It’s important to note that correlation does not equate to causation. In other words, it would be wrong to make the claim that eating processed meat will cause cancer. However, the correlation was observed across multiple studies representing different populations and so should inform dietary decisions by all of us, and especially those with an increased risk for stomach or colorectal cancer.

Research: Nuts and Bolts

Let’s look more closely at the research.

Who is behind this:  The analysis was performed by 22 scientists from 10 countries at the International Agency for Research on Cancer (IARC).

Body of Evidence: The above working group analyzed data from more than 800 epidemiological studies.

Definitions:

  • Red Meat: Any meat (muscle tissue) from a mammal (beef, veal, pork, lamb, mutton, horse, goat); fresh, minced, or frozen.
  • Processed Meat: Any animal protein (this includes the above but also poultry, fish, organ meat (liver), or meat byproducts) that has been transformed through salting, curing, smoking, fermentation, or any other process used to enhance flavor or for preservation.
    • Bacon, ham, sausages, salami, etc

Carcinogenic substances

  • Red Meat: heterocyclic aromatic amines (HAA), Polycyclic aromatic hydrocarbons (PAH), Heme iron
  • Processed Meat: N-nitrosos-compounds (NOC), PAH

Conclusions

  • Processed meat is carcinogenic to humans; linked primarily to Colorectal and Stomach cancers.
  • Red meat classified as probably carcinogenic to humans; Colorectal, Pancreatic, and Prostate cancers.

Red and processed meat cooked at high temperatures produce the carcinogenic substances listed above. These chemicals may cause oxidative stress or genetic changes which promote tumor development, especially affecting the tissue with which they make contact, i.e. colon, rectum, etc.   The more charred or well-done the protein, the higher the level of these compounds.

How much is too much? fresh tasty burger on black background

Epidemiological studies typically categorize consumption into groups: none, low, moderate, and high intake. In this case, high intake of red meat was defined at 200g (about 7 ounces) daily; high intake of processed meat was not clearly defined though it’s likely fewer than 7 ounces. Cancer risk increased as a function of incremental increases of red and processed meat consumption. Colorectal cancer risk increased by 17% for each 100g (3.5oz) of red meat consumed daily and 18% for each 50g of processed meat consumed daily.

This information is helpful in guiding daily choices of red/processed meat. However, it’s important to note that the risk increase is relative and not absolute. If an individual’s baseline risk for colorectal cancer is 20% over their lifetime, eating 3.5 ounces of red meat each day will increase their risk to about 24% (17% of 20% = 3.4%).  Your personal risk for cancer in general, and colorectal cancer specifically (see table below), depends on multiple factors including family history, other dietary choices, lifestyle habits, genetics, etc. These other contributing factors will determine the impact of red/processed meat consumption on your overall risk.

Colorectal Cancer Risk Factors

Obesity Smoking History of IBD Family history of polys
Type II Diabetes Alcohol History of polyps Family history of colorectal cancer
Lack of Exercise Processed Meat Increasing age Genetic predisposition

*Calculate your personal risk here (age 50+): http://www.cancer.gov/colorectalcancerrisk/

But, I can’t live without bacon!

Although some might convert, most meat eaters won’t become vegetarians immediately as a result of this decree.  Meat eaters can incorporate multiple changes in order to reduce their overall risk of cancer development while still enjoying animal protein.  Other dietary choices may reduce colorectal/cancer risk including eating a diet high in colorful fresh/frozen fruits and vegetables, and ensuring optimal daily intake of fiber (at least 30g).  In addition, use portion control when consuming processed and red meat and reduce the number of days red meat is consumed. Limit processed meat to rare occasions.

In addition, lifestyle habits may reduce one’s overall risk of cancer development. Regular exercise and optimal weight maintenance provide multiple benefits in addition to cancer prevention. Smoking and alcohol consumption are strongly associated with multiple types of cancer development- DECREASE or QUIT. Sleep, stress management, and outlook (pessimism vs. optimism) also play important roles in cancer prevention.

Naturopathic doctors are experts in disease prevention and specifically trained to work with individuals to reduce their personal risk of cancer development. If you fall in the category of higher risk or need support for risk reduction. including insomnia and stress management, see a qualified practitioner to put you on the road toward Living for Cancer Prevention.