Spinach extract preparation
’
Thylakoid membranes were extracted from the fresh baby spinach (i.e., Spinacia oleracea) leaves. The leaves were then homogenized, filtered, and diluted with distilled water for ten times. The pH was adjusted to 4.7, which allowed the maximum precipitation. The green precipitate was collected, purified, washed using repeated centrifugation technique, and dried. The green thylakoid powder was manufactured by Darook Pharmaceutical Co., Tehran, Iran. Placebo sachets containing corn starch were colored with edible green color and flavored with kiwi fruit flavor (similar to the flavor added to thylakoid powder) so that the two powders could not be distinguishable in terms of appearance and taste. The packages containing the sachets were coded and distributed monthly by a third party who had no other role in performing the study. The participants’ adherence to taking the sachets on a monthly basis was assessed by counting the sachets returned by them. Consuming more than 80% of the sachets was considered as an acceptable adherence effort.