Dietary protein intake debated at ADA meeting

American Diabetes Association 68th Scientific Sessions

Too many questions remain about the potential adverse effects of a high-protein diet to recommend it as a standard routine diet for patients with diabetes, Joel D. Kopple, MD, argued at the Great Protein Debate here on Saturday.

Kopple, a professor at the University of California Los Angeles and nephrologist at the Harbor UCLA Medical Center, said that high-protein diets can not only increase proteinuria, GFR and intraglomular pressure, but they can also promote uremic toxicity in diabetic patients with advanced kidney disease. “Where there is proteinuria, kidney disease progresses,” Kopple said, adding that high-protein diets can place a patient at risk for osteoporosis, increased calciuria and urinary calcium excretion.

“We don’t know what high-protein diets will do to the kidneys of diabetic patients,” Kopple argued. A meta-analysis of seven studies with diabetic patients found a “clear trend toward the value of low-protein diets to retard progression to chronic kidney disease.”

Osama Hamdy, MD, PhD, medical director of the Obesity Clinical Program at Joslin Diabetes Center in Boston, countered that increased protein intake in a diabetic patient with normal kidney function is associated with reductions in blood pressure, inflammation markers and cardiovascular events.

The EURODIAB IDDM trial in 16 European countries found that blood pressure, not the amount of protein intake, was linked with albumin excretion rate, Hamdy said. Data from the Nurses Health Study, with 120,000 individuals followed since 1976, showed that high protein intake was not associated with renal decline in women with normal kidney function, Hamdy said.

Hamdy said that Joslin’s Why Wait program recommends that obese diabetic patients with normal kidney function reduce their daily calories by 250 to 500 and that their protein intake comprise 20% to 30% of total calories. A 30% fat intake is also recommended. After one year, patients who maintained that diet had significant weight loss, significant reductions in Hb1Ac, and significant decreases in lipid and CRP levels.

“Increasing the protein to 1.5 gm/kg to 2 gm/kg – or 20% to 30% of caloric intake – may enhance weight loss and reduce blood pressure,” he said. Hamdy said that protein intake of 0.8 gm/kg to 1 gm/kg can be recommended for patients who have diabetes and chronic kidney disease.