Red meat

Red meat in traditional culinary terminology is meat which is red when raw and not white when cooked. In the nutritional sciences, red meat includes all mammal meat. Red meat includes the meat of most adult mammals and some fowl (e.g. ducks).



Gastronomic
In gastronomy, red meat is darker-colored meat, as contrasted with white meat. The exact definition varies by time, place, and culture, but the meat of adult mammals such as cows, sheep, and horses is invariably considered red, while chicken and rabbit are invariably considered white. The meat of young mammals such as milk-fed veal calves and sheep, and pigs is traditionally considered white; while the meat of duck and goose is considered red. Game is sometimes put in a separate category altogether (French viandes noires 'black meats').

Red meat does not refer to how well a piece of meat is cooked. Nor does it refer to its coloration after it has been cooked.

Nutritional
The main determinant of the nutritional definition of the color of meat is the concentration of myoglobin. 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 livestock are red meats because they contain more myoglobin than chicken or fish.

Nutrition
Red meat is a source of iron. Red meat also contains protein, levels of creatine, minerals such as zinc and phosphorus, and vitamins such as niacin, vitamin B12, thiamin and riboflavin. Red meat is the richest source of Alpha Lipoic Acid, a powerful antioxidant.

Food pyramid
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, recommends lean forms of red meat.

Cancer
The American Institute for Cancer Research and World Cancer Research Fund stated in their report "Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective" that there is "convincing" evidence that red meat intake increases the risk for colorectal cancer, and that there is "suggestive" evidence that it increases the risk of oesophageal, lung, pancreatic and endometrial cancer. As a result, they recommend limiting intake of red meat to less than 300g (11oz) cooked weight per week, "very little, if any of which to be processed."

Some studies have linked consumption of large amounts of red meat with breast cancer,  stomach cancer, lymphoma, bladder cancer, lung cancer and prostate cancer  (although other studies have found no relationship between red meat and prostate cancer  ).

A 2009 study by the National Cancer Institute revealed a correlation between the consumption of red meat and increased mortality from cancer and cardiovascular diseases, as well as increased mortality from all causes. This study has been criticized for using an improperly validated food frequency questionnaire, which has been shown to have low levels of accuracy.

Colorectal Cancer
Many studies have found a link between red meat intake and colorectal cancer. Professor Sheila Bingham of the Dunn Human Nutrition Unit attributes this to the haemoglobin and myoglobin molecules which are found in red meat. She suggests these molecules, when ingested trigger a process called nitrosation in the gut which leads to the formation of carcinogens. Others have suggested that it is due to the presence of carcinogenic compounds called heterocyclic amines, which are created in the cooking process. However, this may not be limited to red meat, since a study from the Harvard School of Public Health found that people who ate skinless chicken five times or more per week increased their risk of developing bladder cancer by 52 percent.

The AICR and WCRF consider the evidence that red meat causes colorectal cancer "convincing".

Cardiovascular diseases
Red meat consumption is associated with cardiovascular diseases, possibly because of its high content of saturated fat. Specifically, increased beef intake is associated with ischemic heart disease.

A 1999 study funded by the National Cattlemen's Beef Association, an advocacy group for beef producers, involved 191 persons with high cholesterol on diets where at least 80% of the meat intake came from either lean red meat in one group, or lean white meat in another. The results of this study showed nearly identical cholesterol, and triglyceride levels in both groups. This study suggests that lean red meat may play a role in a low-fat diet for persons with high cholesterol.

Red meat consumption is also associated with acute coronary syndrome, as well as stroke. It has also been associated with greater intima-media thickness, an indicator of atherosclerosis.

A 2008 article published in Nature found that red meat consumption was "strongly associated" with increased odds of acute coronary syndrome, with those eating more than 8 servings of red meat per month being 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 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 Seven Countries Study found a significant correlation between red meat consumption and risk of CHD. A significant relationship between red meat and CHD has been found specifically for women, most strongly with regards to processed red meat.

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.

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 to saturated fat, trans fat and dietary cholesterol, rather than red meat per se. An additional confound is that processed meat intake is associated with 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 two 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.

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.