Commonly, especially in gastronomy, red meat is red when raw and dark in color when cooked, in contrast to white meat, which is pale in color before and after cooking. In cooking, only flesh from mammals or fowl is classified as red or white.
In nutritional science, on the other hand, red meat is defined as any meat that has more myoglobin than white meat, white meat being defined as non-dark meat from chicken (excluding leg or thigh), or fish.
Some meat, such as pork, is red meat under the nutritional definition, and white meat using the common or gastronomic definition.
|Chicken Breast||0.005%||White Meat |
|Chicken Thigh||0.18 - 0.20%||Dark Meat|
|Turkey Thigh||0.25 - 0.30%||Dark Meat|
|Pork||0.10 - 0.30%||Red Meat|
|Veal||0.10 - 0.30%||Red Meat|
|Beef||0.40 - 1.00%||Red Meat|
|Old beef||1.50 - 2.00%||Red Meat|
According to the USDA, all meats obtained from mammals (regardless of cut or age) are red meats because they contain more myoglobin than fish or white meat (but not necessarily dark meat) from chicken.
Under the culinary definition, the meat from adult or 'gamey' mammals (for example, beef, horse meat, mutton, venison, boar, hare) is red meat, while that from young mammals (rabbit, veal, lamb) is white. Most poultry is white, but duck and goose are red. Most cuts of pork are red, others are white. Game is sometimes put in a separate category altogether. (French: viandes noires — "dark meats".) Some meats (lamb, pork) are classified differently by different writers.
Some cuts of pork are considered white under the culinary definition, but all pork is red in nutritional studies. The National Pork Board has positioned it as "Pork. The Other White Meat", profiting from the ambiguity to suggest that pork has the nutritional properties of white meat, which is considered more healthful.
In 2011, the USDA launched MyPlate, which didn't distinguish between kinds of meat, but did recommend eating at least 8 oz (227 grams) of fish each week. In 2011, the Harvard School of Public Health launched the Healthy Eating Plate in part because of the perceived inadequacies of the USDA's recommendations. The Healthy Eating Plate encourages consumers to avoid processed meat and limit red meat consumption to twice a week because of links to heart disease, diabetes, and colon cancer. To replace these meats it recommends consuming fish, poultry, beans or nuts.
Red meat is not a uniform product; its health effects can vary based on fat content, processing and preparation. Processed red meat is linked to higher mortality, mainly due to cardiovascular diseases and cancer. There is some evidence that the consumption of unprocessed red meat may have negative health effects in humans.
A 2016 literature review reported that for 100g or more per day of red meat consumed, the risk increased 11% for each of stroke and for breast cancer, 15% for cardiovascular mortality, 17% for colorectal cancer, and 19% for advanced prostate cancer.
In 2015 the International Agency for Research on Cancer concluded that red meat is probably (Group 2A) carcinogenic to humans, reported that for each additional 100g (up to a maximum of approximately 140g) of red meat consumed per day, the risk of colorectal cancer increased by 17%; there also appeared to be increased risk of pancreatic cancer and prostate cancer but the association was not as clear. Put in perspective, in the UK, 56 out of 1000 people who eat the lowest amount of red meat will develop colorectal cancer (5.6%) while 66 out of 1000 high-red meat eaters will develop colorectal cancer (6.6%) (1.17 x 5.6 = 6.6).
A 2012 meta-analysis found an increased risk of gastric cancer with higher consumption of red or processed meat. Red meat itself contains certain factors that, under certain conditions, produce carcinogens like N-nitroso compounds (NOCs).
The consensus on the role of red meat consumption to increased risk of cardiovascular diseases has changed in recent years. Studies that differentiate between processed and fresh red meat have failed to find a link between unprocessed red meat consumption and heart disease. A major Harvard University meta-study in 2010 involving over one million people who ate meat found that only processed meat had an adverse risk in relation to coronary heart disease (CHD). The study suggests that the "differences in salt and preservatives, rather than fats, might explain the higher risk of heart disease and diabetes seen with processed meats, but not with unprocessed red meats." Some mechanisms that have been suggested for why red meat consumption might be risk factor for cardiovascular disease include: its impact on serum cholesterol, that red meat contains arachidonic acid, heme iron, homocysteine, and its high saturated fat content.
Several studies have found a correlation between unprocessed red meat and the occurrence of CHD and certain types of stroke and have controlled for various confounding risk factors. A study of 84,000 women, over a period of 26 years, finds that those with the highest intake of unprocessed red meat, have a 13% increased risk of CHD. Likewise a Harvard study published in 2012, studying mortality as a result of processed and unprocessed red meat consumption finds that one serving of either type of meat a day results in an increased risk of mortality of 13%, while this ratio is indicative of cancer and cardiovascular (CVD) disease, the study indicates that of the 23,926 deaths investigated during the course of the study, 5910 of them were related to CVD and there was no statistical significance between the risk of unprocessed and processed red meats factors in the occurrence of CVD. The disparity between metadata studies definitely need to be addressed, because while one points toward unprocessed red meat being insignificant in certain health risks, there are still correlations to be found in focused large cohort studies.
Unprocessed red meat intake is tentatively associated with an increased risk of type II diabetes, but the link is weaker and less certain than the link between processed red meat and diabetes. Other findings have suggested that the association may be due to saturated fat, trans fat and dietary cholesterol, rather than red meat per se. One study estimated that “substitutions of one serving of nuts, low-fat dairy, and whole grains per day for one serving of red meat per day were associated with a 16–35% lower risk of type 2 diabetes”.
Most processed meat contains at least some red meat. To enhance flavor or improve preservation meat is treated by salting, curing, fermentation, smoking, or other processes to create processed meat. Nitrates and nitrites found in processed meat (e.g. bacon, ham, salami, pepperoni, hot dogs, and some sausages) can be converted by the human body into nitrosamines that can be carcinogenic, causing mutation in the colorectal cell line, thereby causing tumorigenesis and eventually leading to cancer. In its Press Release 240 (16 Oct. 2015) the International Agency for Research on Cancer, based on a review of 800 studies over 20 years, concluded that processed meat is definitely carcinogenic (Group 1) and found that for each additional 50g of processed meat consumed per day, the risk of colorectal cancer increased by 18% (up to a maximum of approximately 140g); it also found that there appeared to be an increase in gastric cancer but this was not as clear.
A 2016 literature review found that for the each additional 50g per day of processed meat (e.g., bacon, ham, hot dogs, sausages) consumed, the risk increased 4% for total prostate cancer, 8% for cancer mortality, 9% for breast cancer, 18% for colorectal cancer, 19% for pancreatic cancer, 13% for stroke, 24% for cardiovascular mortality and 32% for diabetes.
Cooking any meat at a high temperature or smoking meat produces carcinogenic polycyclic aromatic hydrocarbon compounds (PAHs) and heterocyclic amines (HCAs). The subgroups of heterocyclic amines compounds are amino-dimethylimidazo-quinoxaline (MelQx), amino-dimethylimidazo-quinoxaline (DiMelQx), and amino-methyl-phenylimidazo-pyridine (PhIP), which are mostly formed when meat is cooked at high temperatures. Benzo[a]pyrene (B[a]P) is another compound found in meat cooked at extremely high temperatures. Likely because of these factors, marinating fresh lean red meat, and thoroughly cooking it at a low temperature will reduce the production of carcinogenic compounds and thereby lower the risk of colorectal cancer.
The results of our analysis support a moderate positive association between processed meat consumption and mortality, in particular due to cardiovascular diseases, but also to cancer.
In non-linear models, colorectal cancer risk appears to increase almost linearly with increasing intake of red and processed meats up to approximately 140 g/day. Above this level, the risk increase is less pronounced..