Clocking Your Supplements: What the Science Really Says About Timing
A review of 84 studies finds that for generally healthy adults routine vitamin and mineral supplements offer little protection against heart disease, cancer, or early death and may cause harm when taken without a clear need. When timing matters, it’s about absorption rather than the clock: iron absorption can be sharply reduced by coffee and large calcium-rich meals (with a vitamin C boost helping modestly), while vitamin D is better absorbed with fat-containing meals. B12 timing is less crucial unless absorption is impaired by factors like metformin or acid suppressants. In most cases, follow product instructions, consider addressing definite deficiencies, and consult a clinician before adding supplements, especially if you’re on other medications or taking high doses.
