Leucine-Rich Diet Benefits Health, Weight Loss 32507

Leucine-Rich Diet Benefits Health, Weight Loss

URBANA, Ill.--Women consuming a high-protein diet--loaded withthe amino acid leucine--may experience positive health benefits, according toresearch published in February's Journal of Nutrition (133, 2:411-7,2003) (www.nutrition.org). Researchers atthe University of Illinois, Urbana-Champaign, compared the merits of aprotein-heavy diet to a control diet in a study involving 24 overweight womenaged 45 to 56. Women either consumed 68 g/d of protein (control) or 125 g/d(high-protein diet), and both diets were similar in calorie and fat content.Both groups followed the National Cholesterol Education Program's Step 1 dietguidelines.

After 10 weeks, the control group lost an average of 15.3 pounds compared tothe high-protein group's 16.6 pounds. The real difference between the two dietswas seen in health markers. Both diets led to a 10-percent reduction in serumcholesterol, but the high-protein group also experienced a significant decreasein triglycerides. Women in the control group had a higher insulin response tomeals, while women in the protein group experienced better glucose control, aswell as a feeling of greater satiety after meals. The researchers, led by DonaldLayman, Ph.D., concluded the high-protein diet had a better effect on bloodlipids and glucose homeostasis, not to mention body composition (the treatmentgroup lost more body fat and gained more muscle). They suggested high levels ofprotein may up the amount of dietary leucine--an amino acid linked tomaintaining muscle mass and reducing body fat during weight loss.

In the same journal (133, 2:405-10, 2003), some of the same researchersconducted research supporting protein's effects on blood sugar. They reportedthat consuming a high-protein diet stabilized blood sugar levels.

In research published in the January Journal of Nutrition (133,1:261S-7S, 2003), Layman discussed that while amino acids are beneficial for thebreakdown of protein, a framework for leucine intake should be evaluated inregard to creating an effective weight-loss model.

Layman stated in a university press release dated Feb. 6 that protein needsshould be based on body weight, not a percentage of calories consumed. In theweight-loss study, women on the high-protein diet consumed approximately .73g/kg/d.

"Study participants [in the weight-loss protocol] following themoderately high-protein plan, which I call the `Sensible Solution,' were twiceas effective in maintaining lean muscle mass," Layman said. "Musclehelps burn calories but is often compromised during weight loss." He plansto conduct a long-term study on the high-protein diet to further investigate therole of leucine in metabolic control.