What Do Dietitians Think about Red Meat and Cancer?

This is a topic of discussion within the beef industry.

Jan Tilley, MS, RDN, LD

Jan Tilley – MS, RDN, LD – is a nutrition professional who truly believes that red meat, such as lean beef, should be part of a healthy dietary pattern.

Misinformation Can Be Scary

At JTA Wellness, we want to clear up the confusion around red meat and redirect conversation back to the importance of seeking balance and moderation in the foods we choose. The fact is no single food has ever been found to cause cancer. From studying the current American diet, we know that it is heavy in carbohydrates, processed foods and light in high quality protein, fruits and non-starchy vegetables. Nutrient dense lean protein sources, such as lean beef, are key to maximizing energy, building lean muscle mass and creating satiety.

Understanding Diet, Inflammation and Cancer

A key area of interest in the link between diet and cancer is the role of chronic inflammation. To help understand how inflammation can lead to cancer, it is important to understand that there are two types of inflammation found in our bodies – acute inflammation and chronic inflammation.

Acute inflammation occurs when we have a bee sting or flu virus where our immune system jumps into action by sending white blood cells and proteins to help fight off the enemy. When the inflammation is resolved, the immune response shuts down and everything goes back to normal.

Chronic inflammation occurs when our immune system fights to repair an ongoing problem, such as obesity, but never receives the signal to stop. There is a growing body of evidence citing that the link between diet and cancer may be found in chronic inflammation. In this scenario our body mistakenly identifies healthy tissues as harmful pathogens. In addition to causing some types of cancer, chronic inflammation may be the root cause of many of the chronic diseases we see as we age including type 2 diabetes, cardiovascular disease and cognitive decline.

Preventing Cancer with a Healthy Lifestyle

In addition to making unhealthy food choices, it should be noted that there are many behavioral changes that are known to act as factors that can lead to the development of some types of cancer. Some of these risk factors include:

  • Smoking
  • Obesity
  • Leading a sedentary lifestyle
  • Not getting enough sleep
  • Poor stress management

The power of making healthy choices, both in how we fuel and care for our body, remains our best option for preventing the development of many types of cancer. We know that good health requires effort, dedication and determination to pursue an active, disciplined lifestyle that maximizes health and wellbeing.

Red Meat in the Diet

There is an abundance of evidence-based research demonstrating that a healthy, balanced diet rich in vegetables, whole grains, fruits, lean proteins and healthy fats can decrease our risk of developing cancer. Lean beef can be an important part of a healthy diet and is an excellent source of protein, heme-iron, vitamin B12, selenium, zinc and niacin. Certain cuts of beef, such as top sirloin, are not only high in protein but also have less fat than a 3-ounce boneless, skinless chicken thigh When shopping for lean beef, it helps to remember “if it’s round or loin its lean!” Some of America’s favorite cuts of beef are lean, including:

  • Top Sirloin steak
  • Tenderloin steak
  • 93% lean ground beef
  • Flank steak

By selecting cuts of beef from the loin or round you can be sure you are selecting the leanest cuts. For easy and delicious lean beef recipes, visit www.BeefItsWhatsForDinner.com.

Embrace Lean Beef

In summary, lean beef can be a vital part of a healthy, balanced lifestyle. It is a bioavailable source of protein bringing a unique set of important nutrients that are difficult to find in alternate sources. Lean beef can be enjoyed in moderation with fruits, vegetables, whole grains and low fat dairy as a part of a healthy diet.

Fast Facts: What Do IARC’s Findings on Red Meat and Cancer Mean for You?

1. Who is IARC?

The International Agency for Research on Cancer is an agency of the World Health Organization. The IARC’s mission is to review pre-existing research on cancer to determine potential causes and to evaluate the carcinogenicity of specific substances.

2: What does IARC do?

IARC evaluates substances and groups each into a category according to how “hazardous” they decide the substance may be. Hazard refers to the possibility to cause harm under any circumstances. IARC does not evaluate risk – the probability, possibility or likelihood to cause harm. When recommendations are made about important topics like diet and health, it’s necessary to consider hazard and risk together, to understand the complete story. Learn more about the difference between risks and hazard here.

  • IARC has evaluated more than 900 chemicals (e.g. formaldehyde), complex mixtures (e.g. air pollution), occupational exposures (e.g. carpentry), physical agents (e.g. sunlight), biological agents (e.g. hepatitis B virus), and personal habits (e.g. tobacco smoking), but does not specialize in food evaluation.

3: What exactly does IARC mean by red meat and processed meat?

  • According to IARC, red meat refers to “unprocessed mammalian muscle meat”—for example, beef, veal, pork, lamb, mutton, horse, or goat meat—including minced, ground or chopped meat or frozen meat; it is usually consumed cooked.
  • Processed meat refers to “meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavor or improve preservation.” In the U.S., processed meats, such as bacon, sausages, hot dogs and deli meats, primarily contain pork and poultry, but can contain beef as well.
  • It’s important to note that all production and processing methods pertaining to red and processed meat fall into these definitions including conventional, organic, grass-fed and nitrite- and nitrate-free meats, for example.

4: Am I increasing my risk of cancer by eating red meat?

IARC’s classification of red and processed meat as hazardous is based largely on observational studies of people consuming these foods in the context of an overall diet and weak positive associations with increased cancer. Cancer is a complex disease that develops as the result of genetic, environmental, and lifestyle factors. It is impossible, given the nature of observational studies to isolate a single food from a complex dietary pattern and lifestyle. In fact, based on the available scientific evidence, single foods, including beef, haven’t been proven to cause any type of cancer. The strongest science supports a healthy and balanced diet that includes a variety of foods from all food groups. Research shows by far, the most important lifestyle factors to focus on are not smoking, maintaining a healthy body weight and staying physically active.

5: Is IARC recommending that I change how much red meat I’m eating?

No. Remember – IARC has not evaluated cancer risk (the probability, possibility or likelihood of carcinogenicity), only hazard (possibility of carcinogenicity under any circumstances). Evaluating if a certain intake level of meat is related to cancer risk was therefore not considered by IARC. In fact, the World Health Organization published clarification after questions and concerns stemmed from IARC’s report saying “the latest IARC review does not ask people to stop eating processed meats.”

  • On average, Americans consume 5.1 oz (144 g) of protein foods each day (i.e., from meat, poultry, egg, fish/seafood, nuts, seeds and soy products). The Dietary Guidelines recommend at least 5.5 oz (155 g) of protein foods daily, so Americans are consuming protein foods, including red meat, within the Dietary Guidelines recommendations.

6: What does the science actually say?

Research has continuously shown that beef can and should be part of a healthy balanced diet. The available scientific evidence simply does not support a causal relationship between any type of red or processed meat and any type of cancer. The observational studies in humans are limited, inconsistent and the evidence has weakened over time. The most logical rational for the weak positive associations that may be reported in observational studies is that these studies are more representative of overall diet and lifestyle patterns, i.e. confounded by diet and lifestyle factors such as smoking, obesity, low fruit and vegetable consumption and less physical activity, and less representative of any single food’s influence on cancer risk.

  • Take a look at the evidence that was submitted to IARC firsthand and learn more at BeefResearch.org.

7: Should I choose organic beef as a safer alternative?

IARC did not distinguish between different types of production methods when considering red and processed meat. Regardless of your preference, all beef is safe and nutritious whether you choose to buy conventional, organic or grass-fed for example.

8: What about high heat cooking methods – does this mean I should stop grilling my beef?

You can still enjoy grilling meat (including beef) while limiting the formation of heterocyclic aromatic amines (HAA) and polycyclic aromatic hydrocarbons (PAH), which are known or suspected carcinogens that are produced by cooking any meat. HAA and PAH formation can be greatly reduced by monitoring heat level and doneness temperature of meats, poultry and fish when cooking.

  • When cooking meat, use medium heat. High heat can overcook or char the outside of meat. If meat is charred, don’t eat the charred bits.
  • Do not grill over coals that are flaming to help avoid flare ups and charring.
  • Cooking methods that use low heat such as braising, stewing and poaching have been shown to produce negligible amounts of HAA.
  • Learn more about beef cooking temperatures.

 

Understanding the Evidence on Red Meat and Cancer Risk

For nearly 100 years, America’s farmers and ranchers have supported nutrition research to advance the understanding of beef’s role in a balanced and healthful diet, as part of our commitment to providing a wholesome, nutritious food to Americans. Part of that research has included commissioning scientific reviews of the existing evidence on red meat (including beef) and cancer risk. 

The Beef Checkoff and scientists who conducted these reviews recently submitted evidence for consideration in response to a call for data from the International Agency for Research on Cancer (IARC). We invite you to review the evidence that was submitted to IARC firsthand and learn more at BeefResearch.org.

Science Does Not Support International Agency Opinion on Red Meat and Cancer

Evidence Inadequate to Reach Consensus on Cancer Risk

DENVER (October 26, 2015) – An international committee assigned to review all of the available evidence on red meat and cancer risk were divided on their opinion whether to label red meat a “probable” cause of cancer, according to the Beef Checkoff nutrition scientist and registered dietitian who observed the International Agency for Research on Cancer (IARC) process. After seven days of deliberation in Lyon, France, IARC was unable to reach a consensus agreement from a group of 22 experts in the field of cancer research, something that IARC has proudly highlighted they strive for and typically achieve. In this case, they had to settle for “majority” agreement.

“Cancer is a complex disease that even the best and brightest minds don’t fully understand,” says Shalene McNeill, PhD, RD. “Billions of dollars have been spent on studies all over the world and no single food has ever been proven to cause or cure cancer. The opinion by the IARC committee to list red meat as a probable carcinogen does not change that fact. The available scientific evidence simply does not support a causal relationship between red or processed meat and any type of cancer.”

Most scientists agree that it is unrealistic to isolate a single food as a cause of cancer from a complex dietary pattern further confounded by lifestyle and environmental factors.

“As a registered dietitian and mother, my advice hasn’t changed. To improve all aspects of your health, eat a balanced diet, which includes lean meats like beef, maintain a healthy weight, be physically active and, please don’t smoke,” says McNeill.

While IARC represents a select group of opinions, it doesn’t always represent consensus in the scientific community.

A large meta-analysis, published online in May in the Journal of the American College of Nutrition, analyzed the relationship between red meat intake and risk for colorectal cancer and concluded “red meat does not appear to be an independent predictor of CRC risk,” according to Dominik Alexander, PhD, MSPH, the epidemiologist who conducted the research on behalf of the Beef Checkoff.

“There are a constellation of factors that are associated with the probability of getting cancer, which include age, genetics, socioeconomic characteristics, obesity, lack of physical activity, where you grew up, alcohol consumption, smoking and even your profession,” says Alexander. “The bottom line is the epidemiologic science on red meat consumption and cancer is best described as weak associations and an evidence base that has weakened over time. And most importantly, because red meat is consumed in the context of hundreds of other foods and is correlated with other behavioral factors, it is not valid to conclude red meat is an independent cause of cancer.”

According to Alexander, studies in nutritional epidemiology can be highly prone to bias such as self-reported dietary intake, for which habits may change over time. Because of this, associations reported in nutritional epidemiology may be surrounded by uncertainty. For instance, most, if not all, of the observational studies with red meat are limited by confounding factors; for example, studies have shown that people who consume the most red meat are the most likely to smoke, eat fewer fruits and vegetables and be overweight or obese – all of which may confound the relationship between eating red meat and risk of cancer.

Also, more recent studies in large cohorts are now finding either no association or non-significant findings between red meat and cancer. For example, a recent study out of Harvard using the well known The Nurses’ Health Study (NHS) and The Health Professionals Follow-up Study (HPFS) found unprocessed meat intake had an inverse association with distal colon cancer and a weak, statistically non-significant, positive association with risk of proximal colon cancer.

In addition, gold standard nutrition evidence, such as the Women’s Health Initiative and the Polyp Prevention Trial, two large, multi-year randomized controlled dietary interventions, found that a 20 percent reduction in red meat consumption did not reduce the risk of colorectal cancer and/or had no effect on adenoma recurrence in the large bowel. These studies were disregarded from the IARC review.

“Given the weak associations in human studies and lack of evidence in animal studies it is hard to reconcile the committee’s vote,” says nutritional toxicologist James Coughlin, PhD, CFS. “Of more than 900 items IARC has reviewed, including coffee, sunlight and night shift work, they have found only one ‘probably’ does not cause cancer according to their classification system.”

Coughlin, a toxicologist with more than 40 years of experience in meat and cancer, is critical of the IARC review process due to the lack of transparency, selective inclusion or exclusion of studies and broad interpretation of study results that are inconsistent with the conclusions of the study authors.

“In my experience as an observer to an IARC working group, the process typically involves scientists who have previously published research on the substance being reviewed and may have a vested interest in defending their own research” says Coughlin. “In the case of red and processed meat, the overall scientific evidence simply does not support their conclusion.”

 

 

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