Red meat

For other uses, see Red meat (disambiguation).

Red meat, in gastronomy is meat which is red when raw and not white when cooked, and includes the meat of most adult mammals. In nutritional science, red meat is defined as meat with more than a certain level of myoglobin.

Meat that meets a minimum threshold for the concentration of the pigment myoglobin is scientifically classified as a red meat. The white meat of chicken has under 0.05%; pork and veal have 0.1–0.3%; young beef has 0.4–1.0%; and old beef has 1.5–2.0%. According to the USDA, all meats obtained from mammals (regardless of cut) are red meats because they contain more myoglobin than chicken or fish.

In gastronomy, red meat is darker-colored meat, as contrasted with white meat. The meat from mammals such as cows, sheep, veal calves, lamb, pigs, horses is invariably considered red, while chicken and rabbit meat is invariably considered white. Game is sometimes put in a separate category altogether. (French: viandes noires — "black meats")

An uncooked rib roast.

Roast beef.

Nutrition

Red meat contains large amounts of iron, creatine, minerals such as zinc and phosphorus, and B-vitamins: (niacin, vitamin B₁₂, thiamin and riboflavin). Red meat is the richest source of lipoic acid, a powerful antioxidant.

Red meat contains small amounts of vitamin D. The liver contains much higher quantities than other parts of the animal.

USDA recommendations

The 1992 edition of the USDA food guide pyramid has been criticized for not distinguishing between red meat and other types of meat. The 2005 edition, MyPyramid, was incomprehensible but the accompanying website stated that "fish, nuts, and seeds contain healthy oils, so choose these foods frequently instead of meat or poultry" and for people who wanted to eat meat, it recommended lean or low-fat red meat and poultry.

In 2011, the USDA launched MyPlate, which didn't distinguish between kinds of meat, but did recommend eating at least 8 oz of fish each week.

Healthy Eating Plate

In 2011, the Harvard School of Public Health launched the Healthy Eating Plate to better communicate with the public and to make different recommendations than the USDA, which has to contend with lobbying from many quarters. The Healthy Eating Plate encourages consumers to limit red meat and avoid processed meat, and to instead choose fish, poultry, beans or nuts. Its website says: "Eating a lot of red meat and processed meat has been linked to increased risk of heart disease, diabetes, and colon cancer. So it’s best to avoid processed meat, and to limit red meat to no more than twice a week. Switching to fish, chicken, nuts, or beans in place of red meat and processed meat can improve cholesterol levels and can lower the risk of heart disease and diabetes.

Human health

See also: Beef § Health concerns

Red meat is not a uniform product; its health effects can vary based on fat content, processing and preparation. Processed red meat is strongly linked to higher mortality, mainly due to cardiovascular diseases and cancer. There is some evidence too that the consumption of unprocessed red meat may be bad for human health.

Cancer

Epidemiological studies have found that an increased consumption of processed and red meat is associated with an increased risk of colorectal cancer. The risk is not associated with white meat like chicken. The World Cancer Research Fund (WCRF) and American Institute for Cancer Research (AICR) classify red meat consumption as carrying an increased risk of contracting bowel cancer. In the United Kingdom approximately 21% of bowel cancers are associated with red meat consumption. The WCRF recommends limiting intake of red meat to less than 300g (11 oz) cooked weight per week, "very little, if any of which to be processed."

Red meat consumption also increases the risk of lung cancer.

There is suggestive evidence that red meat intake might increase the risk of esophageal, pancreatic, stomach, endometrial and bladder cancer.

There is no good evidence that red meat consumption increases breast cancer or prostate cancer risk.

Mechanisms

Processed meats (like bacon, ham, salami, pepperoni, hot dogs, and some sausages) are preserved by smoking, salting, and addition of certain chemicals like nitrates and nitrites. Nitrates and nitrites can be converted by our body into nitrosamines that can be carcinogenic, causing mutation in the colorectal cell line, thereby causing tumorigenesis and eventually leading to cancer. Cooking red meat at high temperature and smoking produces the carcinogens polycyclic aromatic hydrocarbon compounds (PAHs) and heterocyclic amines (HCA) Red meat itself contains certain factors that, under certain conditions, produce carcinogens like N-nitroso compounds (NOCs) Additionally, the heme iron that gives meat its red color may promote carcinogenesis due to its ability to increase cell proliferation in the mucosa, through lipid peroxidation and/or cytotoxicity of fecal water Both marinating fresh lean red meat and thoroughly cooking the meat at low temperature will reduce the production of carcinogenic compounds and thereby lower the risk of colorectal cancer.

Cardiovascular diseases

The postwar Seven Countries Study found a significant correlation between red meat consumption and risk of CHD and marked the beginning of our current understanding.

Many studies associate red meat consumption with cardiovascular diseases. Specifically red meat consumption is associated with ischemic heart disease, stroke, with greater intima-media thickness, (an indicator of atherosclerosis), acute coronary syndrome, A significant relationship between red meat and CHD has been found specifically for women.

Processed meat vs. unprocessed

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. 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."

Mechanisms

Some mechanisms that have been suggested for why red meat consumption is a risk factor for cardiovascular disease include: its impact on serum cholesterol, that red meat contains arachidonic acid, heme iron, and homocysteine., its high content of saturated fat. Bacteria in the digestive tract of people who eat meat have been found to produce a spike in TMAO when supplied with carnitine (abundant in red meat). TMAO is a metabolite that promotes atherosclerosis, a thickening of the arteries.

Risk

Those that eat more than 8 servings of red meat per month are 4.9 times more likely to have cardiac events than those eating less than four servings per month.

A 21-year follow up of about thirty thousand Seventh-day Adventists (adventists are known for presenting a "health message" that recommends vegetarianism) found that people who ate red meat daily were 60% more likely to die of heart disease than those who ate red meat less than once per week.

The risk of coronary disease due to high cholesterol can be mitigated by switching to a leaner red meat. According to one study, funded by the beef producers advocacy group, National Cattlemen's Beef Association, eating lean meat (both red and white) produced nearly identical cholesterol, and triglyceride levels in both groups.

Diabetes

Red meat intake has been associated with an increased risk of type II diabetes. Interventions in which red meat is removed from the diet can lower albuminuria levels. Replacing red meat with a low protein or chicken diet can improve glomerular filtration rate.

Other findings have suggested that the association may be due to saturated fat, trans fat and dietary cholesterol, rather than red meat per se.

An additional confound is that diets high in processed meat could increase the risk for developing Type 2 diabetes.

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”.

Obesity

The Diogenes project used data from ninety thousand men and women over about seven years and found that "higher intake of total protein, and protein from animal sources was associated with subsequent weight gain for both genders, strongest among women, and the association was mainly attributable to protein from red and processed meat and poultry rather than from fish and dairy sources. There was no overall association between intake of plant protein and subsequent changes in weight." They also found an association between red meat consumption and increased waist circumference.

A 1998 survey of about five thousand vegetarian and non-vegetarian people found that vegetarians had about 30% lower BMIs. A 2006 survey of fifty thousand women found that those with higher "western diet pattern" scores gained about two more kilograms over the course of four years than those who lowered their scores.

A ten-year follow up of 80,000 men and women found that "ten-year changes in body mass index was associated positively with meat consumption" as well as with weight gain at the waist. In a Mediterranean population of 8,000 men and women, meat consumption was significantly associated with weight gain. Data from the National Health and Nutrition Examination Survey showed "consistent positive associations between meat consumption and BMI, waist circumference, obesity and central obesity."

A survey of twins found that processed meat intake was associated with weight gain. Western diets, which include higher consumption of red meats, are often associated with obesity.

Other health issues

Regular consumption of red meat has also been linked to hypertension, and arthritis.

Marketing

Although the USDA classifies pork as a red meat, given nutritional concerns, meat producers are eager to have their products considered "white", so the United States National Pork Board has positioned their product as "Pork. The Other White Meat", playing on the gastronomic definition.

Culture

In some cultures, eating red meat is considered a masculine activity, possibly due to traditions of hunting big game as a male rite of passage.

See also

• White meat