As children our mothers told us to finish our milk because it would make us big and strong. It turns out that the vitamin D enriched creamy goodness many thoughtlessly poor over cereal every morning doesn’t just build strong bones. 2009 has been a banner year for vitamin D related research and has seen the publication of numerous studies revealing that vitamin D isn’t only essential for building bones but serves in a variety of ways to help age against the machine.

Vitamin D is a nutrient and prohormone that occurs in a variety of forms. We can take in vitamin D from food or dietary supplements, or make our own with judicious sun exposure. Regardless of how we get our vitamin D, the vitamin isn’t useful to the body until it can be put through a series of metabolic steps to activate it. These additional steps take the precursor forms of vitamin D and make them biologically active.

It is our understanding of that biological activity that has expanded so much this year:

• The current issue of the British Medical Journal includes a study that finds that supplementing vitamin D reduces the risk of falling amongst the elderly.
• Vitamin D has been found to reduce joint and bone pain.
• Low vitamin D is associated with increased cognitive impairment.
• Insufficient vitamin D increases the risk of dying from heart disease.
• Vitamin D reduces insulin resistance.
• Low vitamin D is even associated with bacterial vaginosis, a common infection.
• Low vitamin D levels results in a shortened lifespan overall.

The list goes on and on. It’s all current research and more is forthcoming.

With the mounting evidence the question becomes just how much vitamin D should one supplement. Most of the supplementation studies use 700 to 1000 IU of vitamin D daily. Is this optimal? We don’t know that for sure yet, but it is a place to start.