What is Vitamin D?
Vitamin D is a fat-soluble vitamin that your body can synthesize when your skin is exposed to ultraviolet B (UVB) light. There are some foods with vitamin D, so we can get it through our diet. Foods like cod liver oil, wild-caught salmon, portobello and maitake mushrooms, sardines and eggs are high in vitamin D.
The preferred way to get vitamin D is through exposure to the ultraviolet B rays in sunlight, but that can be difficult for many either because work keeps us inside all day or we live in the far northern or southern latitudes where there isn’t much UVB in the sunlight even if we can get outside.
Because we don’t get enough from exposure to sunlight, we have to either get it from our food or from supplements.
What Does Vitamin D Do?
Why is vitamin D important? I think everyone knows that vitamin D is necessary for strong bones because the body cannot process and use calcium without it. Calcium is also used by the nerves that cause muscle contraction and beat your heart, so vitamin D plays an important supporting role in movement and circulating blood.
A lack of vitamin D is associated with a variety of conditions. The most common ones, other than reduced bone mass, appear to involve nerve tissue. Some studies indicate that insufficient amounts of vitamin D can contribute to increased risk for depression (including seasonal affective disorder), dementia and Alzheimer’s disease.
One article I found says that vitamin D is actually a steroid hormone and that it is responsible for activating up to 1,000 of the 21,000 active genes that make up the human genome. It says that thirty-seven different tissues in the body depend on vitamin D to function properly.
How Much Vitamin D Do I Need?
The real answer is that it depends. The National Institutes of Health sets the recommended daily allowance of vitamin D at 600 IU for everyone from 1 to 70 years old. It is 400 IU for babies under 1 year and 800 IU for adults over 70. Most of the information that I read from other sources recommends 1,000 IU or even more. Again, the real reason is that it depends on a variety of factors.
The first factor is how much sun do you get? If you live somewhere that gets plenty of sun from high in the sky then you may not need as much. That is, unless you cover yourself with a lot of sunscreen or have dark skin that significantly reduces the amount of ultraviolet B that you receive. If that is the case then you probably need to supplement.
If you live farther north (or south if you live in the southern hemisphere) where days are shorter and the suns rays come in at a lower angle, or no matter where you are if you spend all of your time indoors, then you probably need to supplement. UVB rays are greatly reduced in the higher latitudes and they don’t penetrate buildings at all.
If you are overweight then you need more vitamin D because vitamin D dissolves in fat. Fatty tissue absorbs and breaks down the vitamin D making it unavailable where it is needed. Overweight people also have more blood flowing to support the additional cells, so they need more vitamin D to maintain the proper concentration in their blood. If you needed some incentive to lose weight, there it is.
There are many kinds of vitamin D supplements, so if you need to take additional vitamin D, make sure you get a good quality supplement with vitamin D3. Vitamin D3 is what your body makes and what you get in through your food so your body knows how to process it. I get my vitamin D3 supplement here.
Overweight? You Might Need a Lot More Vitamin D
Can’t Get Enough Sunlight?
Are You Getting Enough Vitamin D?
National Institutes of Health
Disclaimer and Disclosure
I am not a doctor. I do not make any medical claims to diagnose, treat, cure or prevent any condition. I am an independent Shaklee distributor, so I may earn a commission if you order your vitamin D supplement through the link above.