Health Problems Associated with Red Meat
(The following list is comprehensive, although not necessarily exhaustive. Contact your health care professional for more information.)
Atherosclerosis, or hardening of the arteries, is a very common disease of the major blood vessels. It is characterized by fatty streaks in vessel walls and deposits of cholesterol and calcium. This disease frequently leads to heart attacks.
The most important dietary changes for protecting arteries from atherosclerosis include avoiding saturated fat as found in meat (and dairy fat). A reversal of atherosclerosis resulting from a pure vegetarian diet--meaning no meat, poultry, dairy, or eggs--combined with exercise and stress reduction has been reported in medical research.1 Independent of other dietary components, daily consumption of meat has been linked to a tripling of the risk of dying from heart disease compared with avoidance of all meat.2 Others have reported a higher risk of heart attacks in meat eaters.3
Cancer is a general term for more than 100 diseases that are characterized by uncontrolled, abnormal growth of cells. Cancer is the second leading cause of death in Americans. Red meat has been linked to colon cancer in some4,5,6,7,8
though not all studies.9
Genetic factors may determine whether meat eating increases a person's colon cancer risk.10
Both colon and breast cancer have been linked with eating well-done meat.11,12,13
Colon cancer was linked only to processed meat (such as hot dogs) in one report.14
Preliminary studies have linked brain cancer in children to a variety of meats such as bacon and corned meats,15
ham and processed pork meats,16
and possibly hot dogs.17
Cardiovascular disease is the number one cause of death in the United States. Eating animal foods containing saturated fat is linked to high serum cholesterol18
and heart disease.19
Significant amounts of animal-based saturated fat are found in beef, pork, veal, poultry (particularly in poultry skins and dark meat), cheese, butter, ice cream, and all other forms of dairy products not labeled "fat free." Avoiding consumption of these foods reduces cholesterol and has been reported to even reverse existing heart disease.20
Daily consumption of meat has been linked to a tripling of the risk of dying from heart disease compared with avoidance of all meat.21
Although it is by no means the only major risk factor, elevated serum cholesterol is clearly associated with a high risk of heart disease. Eating animal foods containing saturated fat is linked to high serum cholesterol22
and heart disease.23
Significant amounts of animal-based saturated fat are found in beef, pork, veal, poultry (particularly in poultry skins and dark meat), cheese, butter, ice cream, and all other forms of dairy products not labeled "fat free." Avoiding consumption of these foods reduces cholesterol and has been reported to even reverse existing heart disease.24
Although research funded by the beef industry has sometimes suggested that lean beef may have similar effects on cholesterol levels compared with other animal based foods,25 most scientists, nutritionally oriented doctors, and conventional cardiologists recommend reducing the intake of red meat as a way to lower cholesterol and protect against heart disease. Research not funded by the beef industry has shown that switching from red meat to fish leads to a lowering of cholesterol levels.26
Crohn's disease is a poorly understood inflammatory condition that affects the final part of the small intestine and the beginning section of the colon. A high animal protein and high-fat diet (other than fish) has been linked to Crohn's disease in Japan.27
Until more is known, as with many other health conditions, it may be beneficial to eat less meat and dairy fat and more fruits and vegetables.
People with diabetes cannot properly process glucose, a sugar the body uses for energy. As a result, glucose stays in the blood, causing blood glucose to rise. At the same time, however, the cells of the body can be starved for glucose. Diabetes can lead to poor wound healing, higher risk of infections, and many other problems involving the eyes, kidneys, nerves, and heart.
Vegetarians have been reported to have a low risk of type 2, or non-insulin dependent diabetes mellitus.28 When people with diabetic nerve damage switch to a vegan diet (no meat, dairy, or eggs), improvements have been reported after only several days.29 In one study, pain completely disappeared in seventeen of twenty-one people.30 Fats from meat and dairy also cause heart disease, the leading killer of people with diabetes.
Vegetarians eat less protein than meat eaters. Reducing protein intake has lowered kidney damage caused by diabetes31,32 and may also improve glucose tolerance.33 Switching to a low-protein diet should be discussed with a nutritionally oriented doctor.
Fibrocystic Breast Disease
Fibrocystic breast disease is a term colloquially given to a group of very common benign conditions affecting the breast in young women. Both breasts become tender or painful and lumpy, and the symptoms vary at different times in the menstrual cycle.
Fibrocystic breast disease has been linked to excess estrogen. When women with fibrocystic breast disease are put on a low-fat diet, their estrogen levels decrease.34,35 After three to six months, the pain and lumpiness also decrease.36,37 The link between fat and symptoms appears to be most strongly related to saturated fat.38 Foods high in saturated fat include meat and dairy products.
Gallstones are formed in the gallbladder and primarily consist of cholesterol. They are commonly associated with bile that contains excessive cholesterol, a deficiency of other substances in bile (bile acids and lecithin), or a combination of these factors.
Most studies report that vegetarians are at low risk for gallstones.39 In some trials, vegetarians have had only half the risk compared with gallstone risk in meat eaters.40,41 Vegetarians often eat fewer calories and less cholesterol. They also tend to weigh less than meat eaters. All of these differences may reduce gallstone incidence.
Gout is a form of arthritis that occurs when crystals of uric acid accumulate in a joint, leading to the sudden development of pain and inflammation. Individuals with gout either overproduce uric acid or are less efficient at eliminating it. The big toe is the most commonly afflicted joint to accumulate uric acid crystals, although other joints may be affected.
Gout has been clearly linked to dietary factors. Foods that are high in a compound called purine raise uric acid levels in the body. Restricting purine intake can help control uric acid levels and in turn, the risk of an attack in individuals susceptible to gout. Foods high in purine are generally protein-rich foods, such as sweetbreads, anchovies, mackerel, sardines, chicken, dried beans and peas, liver and other organ meats, herring, scallops, red meat, and turkey.
Homocysteine, a normal breakdown product of the essential amino acid methionine, is believed to exert a number of toxic effects in the body. A growing body of evidence suggests that an elevated homocysteine level is a risk factor for heart disease, independent of other known risk factors such as elevated serum cholesterol and hypertension,42,43
though, in some research the link has appeared only in women.44
Since homocysteine is produced from methionine, intake of large amounts of methionine would presumably increase homocysteine levels. Indeed, ingestion of supplemental methionine is sometimes used experimentally as a method of increasing homocysteine levels.45 Foods high in methionine include meat, chicken, fish, and eggs. Although there is little research in this area, reducing one's intake of those foods could theoretically decrease homocysteine levels, thereby potentially reducing the risk of cardiovascular disease and osteoporosis.
Morning sickness is the common but poorly understood nausea that frequently accompanies early pregnancy. Women with a high intake of saturated fat (from meat and dairy) have been reported to have a much higher risk of severe morning sickness than women eating less saturated fat. A Harvard study found that saturated fat equivalent to one cheeseburger or three cups of milk was linked with more than a quintupled risk of developing morning sickness.46
People with osteoporosis have brittle bones, which increases the risk of bone fracture, particularly in the hip, spine, and wrist. When over 85,000 American women were followed for twelve years, those who ate the most animal protein (meat, poultry, and dairy) had a significantly higher risk of osteoporotic fractures.47
Similarly, high protein intake correlates with increased hip fracture in studies comparing different cultures.48
When dietary protein increases, so does the loss of calcium in urine49,50
(though this extra calcium loss is not always statistically significant).51
However, some protein (though not necessarily from meat) is needed for bone formation and too little
protein can also be a risk factor for osteoporosis; protein supplementation in some elderly osteoporosis patients has reduced bone loss.52
People who wish to avoid osteoporosis by avoiding meat, reducing its intake, or replacing meat with vegetable sources of protein should talk with a nutritionally oriented doctor.
Parasites are plants or animals that live upon or within humans to the disadvantage of the infected person. Parasites differ from bacteria in that they are larger (although sometimes still too small to see with the naked eye). Undercooked meats (particularly pork) and poultry can contain parasites. Parasites are killed by adequate cooking.