& Joannie Dobbs Wednesday, June 13 , 2001
Proper protein is necessary
Politicians often complain that their statements are taken out of context and used inappropriately to support the beliefs of others. A single statement or concept can sound very good and straight forward until it is considered in relation to a multitude of other factors.
The same is true in the world of science, especially nutrition science. Factual statements from one study are often applied well beyond what the original research supports. Frequently, the basis for this extrapolation of facts is the "All-American" attitude that if a little is good, then a whole lot is even better. Or conversely, if something is unsafe at high levels, then it could not be beneficial even in moderate amounts.
Dietary protein is a good example of this "all or nothing" attitude. Many people seem to have gotten the message that high-protein diets increase the amount of calcium lost in the urine. For those concerned about osteoporosis and bone health, the seemingly logical action to take is a low-protein diet. That may make sense on the surface, but a significant amount of good research associates low-protein diets with low bone density.
The skeleton primarily consists of protein, calcium, magnesium and water. A diet adequate in these components throughout life seems to be what is needed to support healthy bones. Regretfully, many people who are cutting down on dietary protein may be accelerating bone loss.
Recent research by Dr. Jane Kerstetter of the University of Connecticut indicates that people may need more protein as they age. Kerstetter's work, reported at the American College of Sports Medicine 2001 meeting, indicates that people absorb less calcium when protein intake is even slightly low. Also, more bone calcium is released from bones into the blood due to an increase in a hormone called parathyroid.
Kerstetter found it was necessary to increase protein intake above the current Recommended Dietary Allowance to overcome the negative bone effects. She is not alone in her conclusions. Other recent studies have reported lower bone density and an increased incidence of hip fractures in people with lower protein diets.
As a result, we may see a change in the adult RDA for protein in a revision slated for publication later this year. The RDA may return to its original value of 1 gram of protein per kilogram of body weight (a kilogram equals 2.2 pounds).
Most Americans who eat meat and poultry products are already consuming more than enough protein. Many older people, however, may not be meeting their protein needs as their calorie needs drop with age and they eat less.
The bottom line: As long as you are consuming recommended amounts of calcium, a higher protein diet will not harm bone health. And in fact, a low-protein diet also low in calcium may be bad for bones.
Health is all about balance. This includes a balance in the nutrients we consume and the amount of exercise we do.
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S.
are nutritionists in the Department of Human Nutrition, Food and Animal Sciences,
College of Tropical Agriculture and Human Resources, UH-Manoa.
Dr. Dobbs also works with the University Health Service
© 2001 Honolulu Star-Bulletin -- http://starbulletin.com
Human Nutrition, Food & Animal Sciences · University of Hawai`i at Mānoa
1955 East-West Road · Honolulu, HI 96822
Page was last updated on: