Aging, low-grade systemic inflammation and vitamin D: a mini-review

We conducted a mini-review of the literature, focusing on aging-related systemic inflammation and its association with vitamin D (VitD). As main findings, data indicate that inflammation in aging seems to have multiple origins, including immunosenescence, and from intestinal and adipose tissue, where VitD may modulate these three factors, through mechanisms not totally known. From the selected studies, three randomized clinical trials of VitD supplementation showed improvements in inflammatory status, whereas two studies did not. Ten epidemiological studies showed associations between VitD and inflammation, whereas two studies did not. One case study reinforced this association. As such, we can assume a reasonable association between VitD and inflammation in the elderly, and a promising role of supplementation in some situations. However, most studies did not take into account environmental and individual factors such as the season of the year, latitude, skin color or even the use of some medicines; in addition, the doses, time of intervention and the sample sizes differed between the studies. In conclusion, although more controlled VitD studies, both clinical and epidemiological, are necessary, it is important to remember the network of factors involved in systemic inflammation in the elderly; an understanding of the dietetic and non-dietetic factors is needed to offer a realistic approach.