Who Actually Benefits

The useful cases share a theme: a real gap a normal diet leaves open. A vegan diet has almost no B12, so a supplement prevents nerve damage over time. Early pregnancy needs extra folate to protect the baby's developing spine — before most people even know they are pregnant.

People who get little sun or rarely eat fish can fall short on vitamin D or omega-3s. The logic is always the same: fix a known shortfall, not a vague worry.