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.
- Learn about the role of genetically modified crops in cattle feed , and how those crops are studied for safety before they reach the farm or ranch.
- Get answers to questions about the difference between grass-fed or grain-fed beef, including if one is safer/better than the other.
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.