Influence of chitosan treatment on surrogate serum markers of cholesterol

Chitosan treatment results in significantly lower serum LDL cholesterol 13 concentrations. To assess the working mechanism of chitosan, we measured serum surrogate 14 markers of cholesterol absorption (campesterol, sitosterol, cholestanol), synthesis (lathosterol, 15 lanosterol, desmosterol), and degradation to bile acids (7α-hydroxy-cholesterol, 27-hydroxy16 cholesterol) corrected for cholesterol concentration (R_sterols). Over 12 weeks, 116 obese 17 subjects (BMI 31.7, range 28.1 – 38.9 kg/m2) were studied under chitosan (n=61) and placebo 18 treatment (n=55). The participants were briefly educated regarding improvement of nutrition 19 quality and energy expenditure. Daily chitosan intake was 3200 mg. Serum LDL cholesterol 20 concentration decreased significantly more (P=0.0252) under chitosan (-8.67 ± 18.18 mg/dl, 21 5.6%) than under placebo treatment (-1.00 ± 24.22 mg/dl, 0.9%). This reduction was not 22 associated with the expected greater decreases in markers of cholesterol absorption under 23 chitosan treatment. Also, increase in markers of cholesterol synthesis and bile acid synthesis 24 under chitosan treatment was not any greater than under placebo treatment. In conclusion, a 25 significant selective reduction of serum LDL cholesterol under chitosan treatment is neither 26 associated with a reduction of serum surrogate markers of cholesterol absorption nor with an 27 increases of markers for cholesterol and bile acid synthesis. 28