Why do we need to eat vitamins?

In one sentence: Our bodies can’t produce all of the nutrients that we need to function properly, so we have to eat them.

To understand why we need vitamins, it’s best to first understand what vitamins are.  Vitamins are compounds which are necessary for our normal growth and function, which we cannot make within our bodies, and so we must obtain them from our foods.

Most of the compounds needed for our body cells to function for our health, can be made by our cells from other nutrients.  For some reason, we evolved without the ability to make the small number that we call vitamins.  They were present in ample amounts in ordinary foods throughout evolution, so we did not need to make them.  We only need tiny amounts of vitamins, and they are still present in ample amounts in many foods, but it is possible to become deficient in vitamins, and that damages health.

Did you know?  Other species do not all need the same vitamins.  For example: birds and guinea-pigs, can make their own Vitamin C.

Contrary to common understanding, there is actually no value in consuming extra vitamins, above what is necessary, in ‘supplements’ which is a huge industry.  It has been shown that these supplements can actually damage your health!  Vitamin supplements are however recommended in certain specific situations defined by scientific research.