Vitamin D has appeared more in the news recently, as researchers discover more about the value of this vitamin in treating disease and maintaining wellness. When you read about what a particular vitamin, like D, can do for you, it’s tempting to start supplementing right now. But not so fast: Lets first look at the details of what influences Vitamin D uptake.
The most important role of vitamin D is in promoting the absorption of calcium, and helping bones mineralise at the right rate; recently science has discovered that vitamin D may have a role in regulating immunity and healthy cell reproduction too.
Why shouldn’t you immediately begin supplementing, if you suspect you could be deficient? Because your body contains a multitude of mechanisms for absorbing just the right amount of specific nutrients; and also, if your absorption mechanisms (intestines, liver, kidneys) aren’t in good shape, you’re not going to absorb much of that supplement anyway. Remember too that vitamin D is a fat soluble vitamin; and all fat soluble vitamins can accumulate in your body when you constantly take in more than you need. (Vitamins A, D E and K are fat soluble vitamins). Excess water-soluble vitamins (the B group and vitamin C) are excreted through urine.
Your skin is the main means for your body to absorb vitamin D. Just five to 10 minutes of sun exposure per day, on your arms and legs, will provide 3000IU of vitamin D. After absorption through your skin, a large number of enzymes in your kidneys and liver convert D to its active form. Some vitamin D is absorbed through your diet too, especially oily fish. (100g of canned salmon will provide 300-600IU of vitamin D). The recommended daily intake of vitamin D is just 400IU. Even with just some simple math, you can see how easy it should be to get enough vitamin D. So why are so many people now deficient in this important vitamin? Here are some of the groups considered most as risk:
- People who are institutionalised, like the frail elderly, who don’t often get into the sun
- People whose intestinal fat absorption is defective (like those with irritable bowel, crohns or colitis)
- Some medications can interfere with absorption of fat soluble vitamins
- Those with chronic kidney disease (because your kidneys are an important part of converting vitamin D to its active form)
- Obese members of our population are considered more at risk for vitamin D deficiency. The theory is that excessive fat just under the skin ‘soaks up’ too much of the vitamin D before it reaches the bloodstream.
A blood test to ascertain whether you really need a vitamin D supplement can be arranged through the clinic, if you are a current client. In the meantime, you can help yourself with brief daily exposure to the sun, including oily fish in your diet, and ensuring that your digestive health is good.