The effect of probiotic-enriched kefir compared to regular kefir drinks on stress oxidative and inflammatory markers in elderly overweight and obese participants: a randomized clinical trial

The aim of this study is to evaluate the effect of probiotics-enriched kefir drink on anthropometric indices, oxidative stress, inflammatory markers, lipid profiles, appetite and depression in elderly overweight and obese people.

A parallel randomized double-blind controlled clinical trial of 72 elderly participants, Block randomization with a fixed block size of 4 will be done.

Retired elderly men over 65 will be referred to Motahari Clinic in Shiraz and are randomly assigned into 2 study groups. The informed consent form, demographic information, physical activity (IPAQ), 3-day food record, and visual appetite scale (VAS) questionnaires and geriatric depression scale-15 are completed for all individuals before and after the study. Anthropometric measurements, evaluation of total antioxidant capacity, superoxide dismutase, catalase, glutathione peroxidase, c-reactive protein, malondialdehyde, interleukin-6 and lipid profiles are performed before and after the study. The appearance of the kefir drinks is quite similar.

Inclusion Criteria: Willingness to participate in the study Male gender Age over 65 years Body mass index above 25 Absence of chronic liver, kidney, diabetes, cardiovascular diseases, digestive disorders, chronic infectious diseases, severe neurological and psychological disorders and not taking antidepressants medicine Not taking probiotic supplements within 2 months and antibiotics within the last 3 months Not taking antioxidant supplements Not regularly consuming alcohol (more than three units per week) and smoking Exclusion criteria: Any changes in diet or medications Unwillingness to continue studying Unwanted side effects that improve by stopping the intervention, which will cause participants to withdraw from the study

Group 1 receives the probiotic-enriched kefir drinks. Group 2 receives the kefir drink.

Total antioxidant capacity, superoxide dismutase, catalase, glutathione peroxidase, c-reactive protein, malondialdehyde and interleukin-6

Before beginning the study, an outsider who is familiar with the randomization method prepares 4 blocks of random blocks, then randomly identifies the sequences and groups them in a closed envelope, named A, B, C, and D. After the individuals enter the study, the sealed envelopes containing the assigned group of participants will be opened for each participant based on the sequence determined by the person outside the study.

The appearance of the kefir drinks in which they are packaged are quite similar. The drinks will be named with the Latin letters A and B. In the clinical phase of the study, the random allocation sequence is done with the same letters. Therefore, the researcher and all participants will be blinded to the intervention.