Treating and/or preventing iron deficiency. Without meat in the diet, it is hard for an adult woman to meet her iron requirement without supplements. One cooked 3.5-ounce hamburger provides about 2.9 mg iron, 16 percent of the RDA for an adult woman of childbearing age.

Possible anticarcinogenic activity. Beef is rich in a polyunsaturated fat called CLA (short for conjugated dienole linoleic acid). In 1993 and 1996, research at Purdue University showed that CLA slows or reverses skin, breast, and stomach cancers in laboratory rats and mice at all three stages of tumor development: when a cell is first damaged, when precancerous cells multiply to form tumors, and when tumors begin to enlarge and spread.

Possible anti-diabetes activity. CLA may also prevent Type II diabetes, also called adult-onset diabetes, a non-insulin-dependent form of the disease. At Purdue University, rats bred to develop diabetes spontaneously between 8 and 10 weeks of age stayed healthy when given CLA supplements.

Adverse Effects Associated with This Food

Increased risk of heart disease. Like other foods from animals, beef contains cholesterol and saturated fats that increase the amount of cholesterol circulating in your blood, raising your risk of heart disease. To reduce the risk of heart disease, the USDA/Health and Human Services Dietary Guidelines for Americans recommends limiting the amount of cholesterol in your diet to no more than 300 mg a day. The guidelines also recommend limiting the amount of fat you consume to no more than 30 percent of your total calories, while holding your consumption of saturated fats to more than than 10 percent of your total calories (the calories from saturated fats are counted as part of the total calories from Eat).

Increased risk of some cancers. A diet high in beef fat has been linked to an increased risk of cancer of the colon and rectum.

Food-borne illness. Improperly cooked meat contaminated with E. coli O157:H7 has been linked to a number of fatalities in several parts of the United States. In addition, meats contaminated with other bacteria, viruses, or parasites pose special problems for people with a weakened immune system: the very young, the very old, cancer chemotherapy patients, and people with HIV. Cooking meat to an internal temperature of 140°F should destroy Salmonella and Campylobacter jejuni; 165°F, the E. coli organism; and 212°F, Listeria monocytogenes.

Antibiotic sensitivity. Cattle in the United States are routinely given antibiotics to protect them from infection. By law, the antibiotic treatment must stop three days to several weeks before the animal is slaughtered. Theoretically, the beef should then be free of antibiotic residues, but some people who are sensitive to penicillin or tetracycline may have an allergic reaction to the meat, although this is rare.

Antibiotic-resistant Salmonella and toxoplasmosis. Cattle treated with antibiotics may produce meat contaminated with antibiotic-resistant strains of Salmonella, and all raw beef may harbor ordinary Salmonella as well as T. gondii, the parasite that causes toxoplasmosis. Toxoplasmosis is particularly hazardous for pregnant women. It can be passed on to the fetus and may trigger a series of birth defects including blindness and mental retardation. Both Salmonella and the T. gondii can be eliminated by cooking meat thoroughly and washing all utensils, cutting boards, and counters as well as your hands with hot soapy water before touching any other food.

Decline in kidney function. Proteins are nitrogen compounds. When metabolized, they yield ammonia, which is excreted through the kidneys. In laboratory animals, a sustained high-protein diet increases the flow of blood through the kidneys, accelerating the natural age-related decline in kidney function. Some experts suggest that this may also occur in human beings.

Food/Drug Interactions

Tetracycline antibiotics (demeclocycline [Declomycin], doxycycline [Vibtamycin], methacycline [Rondomycin], minocycline [Minocin], oxytetracycline [Terramycin], tetracycline [Achromycin V, Panymycin, Sumycin]). Because meat contains iron, which binds tetracyclines into compounds the body cannot absorb, it is best to avoid meat for two hours before and after taking one of these antibiotics.

Monoamine oxidase (MAO) inhibitors. Meat "tenderized" with papaya or a papain powder can interact with the class of antidepressant drugs known as monoamine oxidase (MAO) inhibitors. Papain meat tenderizers work by breaking up the long chains of protein molecules. One by-product of this process is tyramine, a substance that constructs blood vessels and raises blood pressure. MAO inhibitors inactivate naturally occurring enzymes in your body that metabolize tyramine. If you eat a food such as papain-tenderized meat, which is high in tyramine, while you are taking a MAO inhibitor, you cannot effectively eliminate the tyramine from your body. The result may be a hypertensive crisis.

Theophylline. Charcoal-broiled beef appears to reduce the effectiveness of theophylline because the aromatic chemicals produced by burning fat speed up the metabolism of theophylline in the liver.