Meat, Cancer Risk, and Nutrition Confusion

No wonder people are confused about nutrition

I was perusing the NY Times website last week, and noticed two articles appearing on the same day:  How Salad Can Make Us Fat and Is Grass-Fed Beef Better for You? No wonder people are confused about nutrition and health! Granted, reading beyond the headlines presents a more nuanced picture. Unfortunately, many people don’t read beyond headlines, and are left with a case of nutritional whiplash… “What? Salad is fattening? And beef is actually good for me?” Given this type of experience, it should come as no surprise that many people do not trust nutrition professionals.

A report worth reading

Despite this, I encourage you to pay attention to the World Health Organization (WHO) report released today on red meat, processed meat, and cancer risk. This report validates what I have always said about grass-fed meat and health: grass-fed meat may be healthier than conventionally-produced, “feed-lot” meat, but that doesn’t necessarily mean it is healthy.

What about grass-fed and organic meat?

Some who advocate for more grass-fed meat, butter, and milk focus on just one aspect of the meat: fat. When people say grass-fed, organic meat is healthier, I always ask, “Healthier than what?” I agree, these products are healthier than conventionally-raised meat. They do have a healthier fatty acid profile. But there’s more to food than one single nutrient or category of nutrients.

Also consider that according to the report from the WHO’s dedicated cancer agency, the International Agency for Research on Cancer (IARC), meat includes all mammalian muscle meat, such as beef, veal, pork, lamb, mutton, horse, and goat. Is there such a thing as grass fed pork? Regardless, keep in mind that in this WHO report, meat refers to all meat, not just beef.

So, back to the grass-fed meat question…based on available research, I believe how you raise the animal does not lessen the increased cancer risk associated with consuming it, particularly if the meat is processed. The WHO report classified the consumption of meat as probably carcinogenic to humans, and classified processed meat as carcinogenic to humans.

This implies that conventional or grass-fed, meat is a probable carcinogen. And once you process either type of meat, it is definitively carcinogenic, according to WHO, and other large health/research agencies, such as the American Institute for Cancer Research (AICR).

Why is meat linked with cancer risk?

In addition to the nitrates/nitrites in processed meats, three key issues to consider with meat in general are:

  • heme iron
  • polycyclic aromatic hydrocarbons (PAHs)
  • heterocyclic amines (HCAs)

Ample evidence suggests heme iron contributes to chronic disease risk, such as heart disease and digestive tract cancers. Heme iron is a strong pro-oxidant. In processed meat, heme iron likely worsens the carcinogenic effects of the nitrites as well.

As for PAHs and HCAs, you cannot avoid these if you eat cooked flesh. These compounds are generated due to the substances naturally found in meat.

  • HCAs are formed when amino acids (protein building blocks), sugars, and creatine (found in muscle) react at high temperatures.
  • PAHs are formed when fat and juices from meat grilled directly over an open fire drip onto the fire, causing flames and smoke, which rise up and coat the meat.

This means you can reduce PAHs by not grilling over open flame, but HCAs are formed regardless, simply because it’s meat plus heat.

There are ways to reduce the generation of these compounds in cooked flesh, but you can never get levels down to zero. Take the AICR quiz on safer grilling to learn more, and check out AICRs enews Guide to Healthy Grilling for additional information.

As an aside, you can grill your carrots and eggplant until they resemble a charcoal briquette, and you will not form PAHs or HCAs, because vegetables do not contain the precursor compounds from which these carcinogens form. You may create other noxious compounds, but the carcinogens PAHs and HCAs are particular to cooked flesh.

While it isn’t definitively known that PAHs and HCAs directly cause cancer in humans, evidence suggests this is the case.

The bottom line

  • Processed meat, regardless of whether it is conventionally-raised or grass-fed, contains nitrates/nitrites, heme iron, PAHs, and HCAs.
  • Fresh meat, regardless of whether it is conventionally-raised or grass-fed, contains heme iron, PAHs, and HCAs.

These substances (nitrates/nitrites, heme iron, PAHs, and HCAs) likely account for at least some of why processed meat and fresh meat are linked with increased cancer risk. Other research suggests animal protein in the diet may increase cancer risk as well.

Finding balance

Most health agencies do consider the adage, “the dose makes the poison,” when advising on meat consumption. Many of these agencies suggest up to 18 ounces of meat per week is not likely to measurably increase cancer risk. They do advise that no amount of processed meat is known to be “safe,” though they stop short of saying, “never eat these foods.”

The WHO/IARC report also stopped short of giving a definitive amount of meat that is “safe to eat.” According to Dariush Mozzafarian, MD, DrPH, the dean of the School of Nutrition Science and Policy at Tufts University, there’s not enough evidence to give meat eaters a specific amount that is safe to consume. However, as Dr. Mozaffarian detailed in a recent interview, his recommendations are “no more than one to two servings per month of processed meats, and no more than one to two servings per week of unprocessed meat.”

Keep a robust “health bank account”

I believe it’s important to note that we all engage in ‘pro-cancer’ and ‘anti-cancer’ behaviors all the time. This will help you keep scary nutrition news stories in perspective. I like to think of it this way. We all have a personal “health bank account.” We are constantly making deposits (improve health) into our health accounts and withdrawals (not so good for health) from them.

For example, perhaps you exercised today… that’s a deposit. You met a friend for coffee… that’s a deposit (social support improves health!). You had two glasses of wine with dinner… that’s a withdrawal. You ate a 12 ounce T-bone steak… that’s a withdrawal too. You don’t smoke and you maintain a healthy body weight… both are very important deposits. And so on.

There’s no way anyone can consistently make only deposits and take no withdrawals. Think how boring and pleasureless life would be! Life should be joyful, and most of us need to make “health account withdrawals” to enjoy ourselves fully. And if you make only deposits, you may have orthorexia, which is defined as an “unhealthy obsession” with otherwise healthy eating. The term “orthorexia nervosa,” literally means “fixation on righteous eating.”

I encourage people who are concerned about these issues… We all have to find which things bring us enough pleasure to justify making a withdrawal on our health account. For me, meat and animals foods don’t give me pleasure, so I don’t use my “withdrawals” for those things. Alcohol, on the other hand, which is considered a carcinogen, is something I enjoy. I’m more than happy to take a “health account withdrawal” to meet friends for a drink, and I like a beer or glass of wine with dinner. That’s my balance.

We tend to get hung up on the “minutia” of nutrition. These nitty gritty details are enough to drive anyone crazy. This is why I advocate focusing on the big picture with nutrition. As the journalist and author Michael Pollen succinctly stated, “Eat food. Not too much. Mostly plants.”

In other words, eat real food, not the processed junk that comes in plastic wrap; don’t overeat, so you can maintain a healthy body weight; and if you eat animal foods, such as meat, eat it sparingly, and balance it out with eating plenty of healthy vegetables, fruit, legumes, nuts, seeds, and whole grains.

This aligns very nicely with Dr. Mozaffarian’s recommendation on meat: “no more than one to two servings per month of processed meats, and no more than one to two servings per week of unprocessed meat.” That leaves a lot of room on your plate for plant foods.

I believe that if we all followed this advice, it would go a long way toward reducing cancer burden. Of course, making these healthy, unprocessed foods widely available to all communities, and giving people the tools and skills to integrate these items into their lives must be tackled too.

As a final note, there certainly are other opinions on this… The National Cattlemen’s Beef Association’s FB page has a link:
Science Does Not Support International Agency Opinion on Red Meat and Cancer. My advice? Consume this story at your own risk.
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