Vitamin D

I was amazed to read recently that vitamin D deficiency is on the increase. Rickets, to use it’s medical name when presenting in children, was primarily a Victorian disease associated with poor diet. It was considered pretty much wiped out among 1st and 2nd world countries where diet is, or at least should be, adequate to prevent it but now the numbers being diagnosed are increasing, as reported by the BBC. It has been more commonly associated with women who have had multiple pregnancies and breast-fed whilst not achieving adequate daily intake. They deplete their own stores of vitamin D, putting them at risk of the adult version of the disease called osteomalacia, but also do not supply their breast-fed children with sufficient stores at a time when bone is being formed.

Vitamin D deficiency causes poor bone formation which in children causes soft bones that easily become deformed. In adults, vitamin D deficiency is classified as osteomalacia and results in an increased fracture rate. It arises for a number of reasons:

1. Poor diet. Vitamin D is found in the skin of oily fish and fish oils. It is also present in small amounts in some beef liver, cheese and egg yolks.

2. Direct sunlight. It’s primary source is from direct sunlight. It is absorbed through the skin and metabolised into a usable form by firstly the liver and secondly the kidneys.

3. Supplementation. Many calcium supplements also contain vitamin D and it is also added to other dietary products to fortify them. This is common with many cereals and some milk products, both specifically targeted to children.

1. Breast-fed babies may be at risk depending upon the mother’s vitamin D stores. A breast-feeding mother that has a good intake of vitamin D is less likely to have a child develop rickets.

2. The elderly will be at risk because as we age, liver and kidney function becomes reduced so the ability to convert vitamin D into it’s usable form is affected.

3. Dark skinned people are believed to be at a slightly higher risk because the higher levels of melanin which causes their skin to be darkened reduces the level of vitamin D absorbed. It is unclear whether this is significant as there are no higher fracture rates in those from African-American ancestry.

4. Those with limited contact with direct sunlight will also be at risk. We are all advised to cover up to protect ourselves against the sun to prevent skin cancer but if taken to extreme, it could have a detrimental effect on our health. The other option is to use a high spf sunscreen but it is unclear whether this has an effect on how the skin absorbs vitamin D. Many people also cover their skin for religious purposes or may have limited access to direct sunlight for other reasons, such as shift/night workers. If this is prolonged, they are at risk of becoming deficient.

5. People who have problems absorbing fat are at risk because vitamin D is fat-soluble. A degree of fat is required for the body to absorb it so those who are unable to absorb fat in turn cannot absorb vitamin D.

6. People that are obese, ie with a body mass index >30, tend to have low levels of the active form of vitamin D in their blood. This is due to the high levels of fat below the surface of the skin which affects how it is absorbed. People who have had gastric bypass are also at risk as the are when it is absorbed is bypassed and over a period of time, they cannot compensate.

The potential is that quite a large percentage of the population could be at risk of developing vitamin D deficiency and not be aware of it because they consider themselves to be healthy.

Most supplements that can be purchased without a prescription tend to be calcium with added vitamin D, such as Forever calcium. This product has the added benefit of containing magnesium which is required to aid absorption.

If you fall into one of these categories, or you think you are at risk, you should consider increasing your daily intake of vitamin D. The easiest way is by taking a  supplement, such as Forever calcium, because the damage could have started as early as your teenage years.