evaluation of the effects of ramadan fasting on lymphocyte subpopulations in a two‐year follow‐up

today, the intractions of the immune system of the immune system, nutrition, and nervous system are one of the main research areas of interest in immunology and disease treatment. due to changes in the mood, behavior, and diet of an individual during fasting period, the body's internal homeostasis is affected. the aim of the present study was to evaluate the effects of ramadan fasting on lymphocyte subgroups, which are the main specific immune cells in the body. for this purpose, in years 1999 and 2000, thirty‐eight healthy muslims (9 females and 29 males), within the age range of 17 to 51 years (mean age=35.4 years), were assessed before the start and one day before the end of ramadan. the pre‐lymphocytic subpopulations analysis was conducted using flow cytometery. the results showed that the percentage of total lymphocytes was 25.82% and 26.23% in the pre‐ and late‐ramadan periods, respectively; the observed difference was insignificant. however, the absolute lymphocyte counts were 2.3×103 and 2.1×103 mm3 before and late ramadan, respectively, and the difference was considered significant (p‐value=0.06). the percentage of cd3+ cells (t cells) was 70.12% before ramadan and 70.25% late ramadan, and the absolute lymphocyte counts were 1.6×103 and 1.5×103 mm3, respectively; therefore, the differences were not significant. regarding the subgroups of cd4+cells (th), the percentage ratios of the cells were 53.46% and 52.8% in the pre‐ and late ramadan periods, and the absolute counts were 0.087×103 and 0.081×103 mm3, respectively; however, the differences were not significant in this cell subgroup. the percentage of cd8+ (tc) cells was 37.7% before ramadan and 37.8% late ramadan, and the absolute counts were 0.6×103 and 0.54×103 mm3 in the pre‐ and late‐ramadan periods, respectively; therefore, the differences were considered insignificant. in addition, the percentage ratios of blymphocytes cells were 14.56 % and 14.74% in the pre‐ and late‐ramadan periods, and the absolute count changed from 0.35×103 to 0.3×103 mm3. according to the results, the differences were not significant, therefore, it seems ramadan fasting does not affect these cells. moreover, the percentage of activated t cells or tdr+, which are involved in specific immune responses, has not been affected by fasting. in fact, the percentage ratios were reported as 11.14% and 10.54% in the pre‐ and late‐ramadan periods, and the absolute count changed from 0.14×103 to 0.11×103 mm3; the differences were not considered significant. finally, the ratio of cd4+/cd8+ cells or th/tc changed from 1.48% before ramadan to 1.5% late this month; however, this difference was insignificant. thus, the overall results indicate that ramadan fasting during winter does not affect the lymphocyte count, percentage ratio, and the main lymphocyte subpopulations.