Random allocation & intervention
The participants were allocated into two groups (curcumin and placebo) using block randomization with a ratio of 1:1. Identical black opaque bottles numbered consecutively (in order of allocation) were used to conceal what was allocated to each participant. The bottles were prepared by a third party that had no role in the sampling or gathering and analysis of data. The curcumin and placebo were produced by Dineh Iran pharmaceutical company (Qazvin, Iran). The intervention group received two 500 mg tablets of edible curcumin together at the same time per day for twelve weeks while the control group received placebo tablets similar to curcumin. Placebo and curcumin tablets were identical in terms of weight, shape, color and smell.