Chitosan supplementation and fat absorption in men and women

Chitosan is a primary ingredient in dietary weight-loss supplements. Its claimed activity is the binding and trapping of dietary fat, leading to fat excretion and weight loss without caloric restriction. We tested the fat-trapping capacity of a chitosan product in men and women.

Participants (12 men, 12 women) were instructed to follow customized diet plans (five meals/day for 12 days). Oral charcoal markers defined two 4-day experimental periods. Two capsules were taken five times per day before each meal during the supplement period (2.5 g chitosan/day) and not during the control period. Feces were collected from day 2 to day 12. Feces from each period were pooled and analyzed for fat content.

For men (mean+/-standard deviation=24.8+/-5.1 years, body mass index [BMI; calculated as kg/m 2 ] 26.6+/-4.5) the average daily was 137+/-31 g fat and 3,256+/-624 kcal. For women (23.3+/-5.0 years, BMI 24.1+/-3.5) average daily 89+/-16 g fat and 2,110+/-195 kcal. Each two-capsule dose was consumed with 28+/-11 g fat in males and 18+/-7 g in females (range =10-76 g/dose). Fecal fat excretion increased with chitosan by 1.8+/-2.4 g/day in males, P =.02, and did not increase with chitosan (0.0+/-1.4 g/day, P =.99) in females.

The fat trapped was clinically insignificant. For men, it would take more than 7 months to lose 1 pound of body fat. For women, no fat was trapped. This product, as with other similar products, fails to meet claims.