Protein pitfalls: exceeding or easing protein requirements may be harmful to your health

American Fitness, July-August, 1996 by Christie Knudsen

Helen drastically altered her diet' last year. Worried by reports trumpeting the hazards of the protein-rich American diet, she cut out cheese, beef, poultry, eggs, and limited her intake of beans and milk to one cup each a day. She ate about 1,800 calories a day--theoretically enough for her height, weight and activity level--but she was getting less than half the Recommended Daily Allowance (RDA) of protein.

During the nine-month period that followed her switch to a low-protein diet, she was surprised by a gradual loss of vitality. She had five colds, her proportion of body fat increased by 10%, she frequently felt tired during the day, and had to switch to lifting lighter weights. Helen expected better health, but found herself worse off. What happened?

The real target of the eat-less-protein campaign is the "average" American consuming 90 to 120 grams of animal protein every day. Such excessive protein consumption may raise the risk of developing osteoporosis, heart disease and cancer. Animal protein--especially beef--is loaded with artery-clogging saturated fat and cholesterol, and excessive consumption is also associated with osteoporosis. However, eating too little protein can be as harmful as eating too much. Moderate protein consumption provides essential amino acids, boosts immunity and maintains strength and muscle function.

Benefits of Protein

Virtually all of the molecules that regulate metabolism and keep the body functioning, including hormones, enzymes, and the oxygen carrier hemoglobin, are proteins. But the ability to produce vital proteins is based on the availability of amino acids. "Amino acids are the building blocks of proteins, and we have to get essential proteins (the ones we can't make) from dietary protein," explains Kyle Brown, M.D., of St. Louis University Medical Sciences Center. "To make sure you get enough amino acids, you need to eat the RDA of protein every day."

What happens if you are like millions of men and women who don't eat enough protein? "Common problems include muscle wasting, loss of muscle strength, longer recovery time from illness, and overall depressed immunity," says Brown.

Many experts agree a protein-poor diet can lead to serious problems. Marilyn Crim, M.D., Ph.D., and her colleagues at Tufts University studied two groups of elderly women. Those who ate 25 grams daily (half their RDA) lost lean body tissue, muscle strength and immune response, while the women who consumed 50 grams a day had improved immune response, stronger muscles and better muscle function. "Protein has been bad-mouthed in the press to the point that there are people who are not eating very much," notes Crim. "Decreases in lean body mass and immune response normally associated with aging may be due, in part, to chronic protein deficiency."

While Crim's work clearly shows dietary protein equal to the RDA is health-sustaining, there is little evidence to support claims by supplement manufacturers that athletes' protein requirements are greater than those of the general population. The American Council on Science and Health recently issued a report citing the marketing of anabolic protein supplements as "false and misleading." In addition, The New York City Department of Health called the promotion of strength-boosting protein powders "an economic hoax with unhealthy consequences." According to Joe Millward, Ph.D., an exercise physiologist at the University of Surrey, England, "Athletes need more calories than the average sedentary person--not extra protein."

Americans usually connect protein with meat like burgers, steaks, hot dogs or sausages. Red meat, especially ground beef, is the largest source of artery-clogging saturated fat in the average American's diet. Saturated fat raises cholesterol and is strongly linked to heart disease.

Heavy red meat consumption is also associated with colon and prostate cancers. Men who eat red meat as a main dish five or more times a week have four times the risk of colon cancer than men who eat red meat only, once a month, according to Edward Giovannucci, M.D., an epidemiologist at Harvard Medical School.

"The fat and cholesterol in meat may be responsible for higher rates of heart disease and cancer," says Andrew Nicholson, M.D., director of preventive medicine at Physicians Committee for Responsible Medicine in Washington, D.C. "The carcinogens created when meat is cooked could also be culprits."

Some believe the large amount of iron in red meat may initiate free radical attacks on cells. Damage by free radicals may cause cells to mutate and become cancerous, or, if they are in artery walls, to accumulate fat and contribute to heart disease. Other experts point to the lack of fiber in red meat as a contributing factor to these diseases.

What meat eaters don't consume may also play a role in heart disease and cancer. Studies indicate as people eat more meat, they tend to incorporate fewer fruits and vegetables into their diet. Studies have demonstrated fiber- and antioxidant-rich fruits and vegetables offer protection against many diseases.