Aged garlic extract supplementation modifies inflammation and immunity of adults with obesity: A randomized, double-blind, placebo-controlled clinical trial

Summary Background Obesity is a serious global health issue and often results in low-grade systemic inflammation, increasing the risk for several chronic diseases. If obesity-induced inflammation could be reduced, fewer complications and co-morbidities might occur. Objective To investigate whether daily supplementation with aged garlic extract (AGE) could reduce chronic inflammation and improve immune function in adults with obesity. Methods Fifty-one healthy adults with obesity (mean age 45.6 ± 1.6 years, mean BMI 36.1 ± 0.9 kg/m 2 ) were recruited to participate in a parallel, double-blind, placebo-controlled, randomized study. After being matched by BMI, participants were randomized into the AGE supplementation or placebo group. Participants were asked to take a divided daily dose of 3.6 g AGE or placebo, with food for 6 weeks. Blood lipid and inflammatory markers were assessed at baseline and after 6 weeks of supplementation. Additionally, peripheral blood mononuclear cells (PBMC) were isolated from whole blood and used to detect changes in immune cell populations and levels of cytokine secretion. A one-way ANCOVA was performed to evaluate differences between the two groups, controlling for respective baseline values. Results At the end of study, serum IL-6 (p = 0.04) and TNF-α (p = 0.05) of participants consuming AGE were significantly lower than those consuming the placebo capsules. PBMC flow cytometry results showed that participants from the AGE group had a higher proportion of γδ-T cells (p = 0.03) and a lower proportion of NKT cells (p = 0.02) in the total population of lymphocytes. There was no difference in percentage of NK cells between the two groups. A significant difference in blood LDL concentration was also observed (p = 0.05). Total cholesterol and non-HDL cholesterol tended to differ between participants from the AGE group and those from the placebo group, although values did not achieve statistical significance. Conclusion Six weeks of AGE consumption modulated immune cell distribution, prevented the increase of serum TNF-α and IL-6 concentrations and reduced blood LDL concentration in adults with obesity. AGE, taken consistently, may be beneficial in preventing the development of chronic diseases associated with low-grade inflammation in adults with obesity. Registered under ClinicalTrials.gov with the identifier code NCT01959646 .