By Susan Burke March, MS, RDN, LD/N, CDE
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The Facebook posts were coming hot and heavy, mostly chewing out “scientists” for the scary headlines that said that bacon and red meat was as bad for you as cigarettes and asbestos.
But the World Health Organization (WHO) never said that. What they did say is that high consumption of processed meats like bacon and sausage is a major risk factor for colorectal cancer.
As always, correlation is not causation, and meat won’t kill you in the same way as tobacco use will. Smoking causes lung cancer — processed meat and red meat contain substances that are carcinogenic.
First, the facts
A subsidiary of WHO, the International Agency for Research on Cancer (IARC), carefully assessed human risk for cancer from all sorts of things, from pesticides to sunlight. They grouped substances into five categories. Known carcinogens were slotted into the highest tier, Group 1; 2A are slightly less risky as “probably carcinogenic”, and 2B is “possibly carcinogenic”, and Group 3 is unclassified, because the data is not conclusive. Processed meats landed in the Group 1 tier — they contain substances that are known carcinogens.
This report was issued by a working group of 22 scientists and health experts for the IARC: they examined more than 800 studies on how likely substances in this disparate group are to cause cancer.
By the way, “red meat” includes “fresh” beef, lamb, or pork — any fresh meat except for (unprocessed) poultry and fish — fresh poultry and fish are not linked to increased risk for cancer.
Processed meat means any meat that has been cured, salted, smoked or otherwise preserved in some way — organic or not — including sausage, hot dogs, salami, pepperoni, and ham.
The risk for developing colorectal cancer is about 17% higher in those people who ate the MOST processed meat compared to those who ate the LEAST. They also found a higher risk for stomach cancer in people consuming the most processed meat compared to those who ate the least.
High red meat consumption is linked to a higher risk for colon, pancreatic and prostate cancer compared to people who ate the least amount of red meat.
It’s All Relative
Cancer Research UK points out that this is relative risk, and there are many different factors that play into this assessment. They explain that in the United Kingdom, about 61 in 1,000 people will develop bowel cancer in their lifetime. Compare that to the 56 in 1,000 who eat the LEAST amount of processed meat. Those who eat the MOST processed meat will raise their risk to about 66 in 1,000 — about five cases more thank average, but 10 more compared to those who eat the least. Does this seem significant? Depends if you’re in that group who develops colon cancer from consuming too much processed meat.
The WHO report detailed why processed meats are linked to development of cancer.
Some of the substances used in the smoking process to preserve meats may lead to the formation of the cancer-causing compounds called polycyclic aromatic hydrocarbons (PAHs).
Processing meat often involves using nitrites as preservatives to prevent bacterial growth and as coloring agents, but nitrites may form compounds called N-nitroso compounds.
Red meat’s color is due to heme iron, which may also stimulate the production of N-nitroso compounds in the gut. The compounds have been found to cause cancer in animal studies.
Cooking methods in fresh meats can be linked to cancer. High-temperature methods, such as grilling, frying or broiling, which might be used with beef or pork, can form more cancer-promoting chemicals, such as heterocyclic amines (HCAs), and the char on the outside of meats can contain PAHs.
As reported by Livescience.com, although the WHO report didn’t make any dietary recommendations in presenting this report, the American Cancer Society Guidelines on Nutrition and Physical Activity and Cancer Prevention currently advise people in a very general way “to limit how much processed meat and red meat they eat”.
The guidance from the American Institute for Cancer Research includes specific amounts of meat in its dietary recommendations.
They recommend that people avoid eating processed meat, or reserve eating it to only a few special occasions such as a special outing to the ballpark, or a barbeque.
For red meat, the American Institute for Cancer Research recommendations call for eating no more than 18 ounces of cooked red meat weekly, which is an amount that doesn’t increase colon cancer risk appreciable, based on an evaluation of the evidence done for AICR by a worldwide panel of experts.
The Portion Makes the Poison
Red meat offers some nutritional benefits, including a good source of protein, iron, zinc and vitamin B-12 in some people’s diet, but not too much, and not too often. A 3-ounce serving looks like a deck of cards.
Although red meat and especially processed meats contain chemicals that have been definitively linked to increase risk for bowel cancer and some other cancers, exposure to carcinogens doesn’t necessarily equate to cancer. It’s important to remember that these groups show how confident IARC is that red and processed meat cause cancer, not how much cancer they cause. (Thanks to CancerResarchUK.com for the graphics).
However, that doesn’t mean we should ignore the comprehensive research that shows repeatedly those people who eat more processed meats consistently have higher rates of cancer — as Dr. David Katz, Founder at True Health Coalition notes, it’s not just isolated exposure to meat of any kind — risk is related to quantity, frequency, and duration.
November is National Diabetes Awareness Month. More than 80% of people with diabetes have type 2 diabetes, formerly known as adult diabetes. But increasing numbers of younger people are either pre-diabetic, or just undiagnosed, which increases their risk for complications from uncontrolled high blood sugars, especially heart disease, and cancer.
People who eat large amounts of red and processed meats are more likely to eat fewer fruits and vegetables. And they’re also more likely to be overweight or obese.
Whether it’s from the local butcher or your supermarket, the evidence so far suggests that it’s probably the processing of the meat, or chemicals naturally present in it, that increases cancer risk.
The news about processed meats isn’t “news”…and it’s something that shouldn’t be ignored now — or previously. One thing for sure, unlike what I’ve heard more than once in response to this announcement, everything does NOT cause cancer, and some foods and behaviors, like eating lots of processed meats, and not eating enough vegetables and fruit, does increase your risk.
Not in the same way as smoking cigarettes increases risk, but meaningfully compared to eating a whole foods, mostly plant-based diet.
To conserve the planet’s ecosystems and their diverse plant and animal species, human populations should consume less meat, according to researchers at Florida International University.
Producing livestock, including cattle, goats and sheep, for human consumption is the single largest driver of habitat loss and deforestation worldwide. It accounts for 75 percent of agricultural land and is a leading cause of climate change, soil loss, water pollution, and the loss of wild carnivores and herbivores.
Eating To Live — Healthfully
A lot of people worry that they won’t get enough protein if they reduce their meat consumption. But the average North American eats almost twice the daily-recommended intake of protein. Here in Cuenca, it’s rare to see locals making meat the focus of their diet — it may be on the plate, but not in platter-sized portions.
It’s easy to meet your daily protein needs from plant-based sources. Nuts, beans, seeds, soy and quinoa are all meatless sources of protein that are easy to prepare and easy on your budget. (Choose organic where possible.) Vegetables contain protein: spinach (2.1 grams per 2 cups raw) and broccoli (8.1 grams per one cup chopped), to name just two. More sources of plant protein from the Vegetarian Resource Group.
I found a useful blog post by The Diet Rebel. She wisely says that if you put your health first, it’s best to avoid processed meats, and if you do, go for the “uncured” varieties, without sodium nitrites. Choose organic if possible, to avoid the added risk of antibiotics, commonly fed to “factory-farmed” livestock.
Avoid Sodium Nitrite: it’s a major ingredient in red meat products:
Beef jerky, bacon, sausage, hot dogs, sandwich meats (ham, bologna, salami), frozen pizza with pepperoni, canned soups with meat, and frozen meals with meat.
If you choose to eat meat, choose fresh meats: (not farmed) fish, poultry, lean beef.
Your Best Bet for Preventing Colon Cancer
Regular screening for colon cancer is one of the most powerful weapons for preventing colon cancer. If you have a strong family history of colon cancer or polyps, for example a first degree relative (parent, brother, sister, child), talk to your doctor about screening. Today’s genetic testing allows you to discuss with your doctor or genetic counselor about getting screened early if you do have a family history.
Regular screening can, in many cases, prevent colon cancer altogether. Learn more from the American Cancer Society here.
Susan Burke March, a Cuenca expat, is a Registered and Licensed Dietitian, a Certified Diabetes Educator who specializes in smart solutions for weight loss and diabetes-related weight management. She is the author of Making Weight Control Second Nature: Living Thin Naturally—a fun and informative book intended to liberate serial dieters and make healthy living and weight control both possible and instinctual over the long term. Do you have a food, nutrition or health question? Write to me at SusanTheDietitian@gmail.com