People who have a higher vitamin D intake may be slowing down a biological process linked to aging https://sciencedirect.com/science/article/abs/pii/S0002916525002552 Vitamin D supplements help slow telomere shortening linked to biological aging https://dailymail.co.uk/health/article-14736021/breakthrough-harvard-study-common-supplement-reverses-aging.html Vitamin D3 (2000–4000 IU/day)