From Wikipedia: >In sunny countries such as Nigeria, South Africa, and Bangladesh, there is sufficient endogenous vitamin D due to exposure to the sun. However

From Wikipedia: >In sunny countries such as Nigeria, South Africa, and Bangladesh, there is sufficient endogenous vitamin D due to exposure to the sun. However, [Rickets] occurs among older toddlers and children in these countries, which in these circumstances is attributed to low dietary calcium intakes due to a mainly cereal-based diet If you treat food as simple calorie numbers, you end up with deficiencies with very bad consequences. This is just an example that I found interesting.