Vitamin D, also known as the ‘sunshine vitamin’, was originally thought to play a role only in the mineralization of bones and teeth by maintaining the correct phosphorous /calcium ratio. Now research has linked low vitamin D levels with obesity, diabetes, cardiovascular disease, osteoporosis, cancer and even depression.
The way doctors measure if you’re deficient in vitamin D is by testing your 25(OH)D level, but most doctors just call this a vitamin D test. Getting this blood test is the only accurate way to know if you’re deficient or not.
There are two ways to get more vitamin D: by exposing your bare skin to the sun or by taking vitamin D supplements.
There are two types of vitamin D supplements: vitamin D3 (cholecalciferol), which comes from fish oil, and plant source D2 (ergocalciferol), which is found in fortified foods and some supplements. D2, found in plants and made active by irradiation, is less biologically active.Vitamin D3 is found in eggs, organ meats, animal fat, cod liver oil, and fish. It is equivalent to the vitamin D3 formed on your skin from UV-B. You should stay away from the synthetic D2 as it has been shown to be toxic at the higher dose ranges.You will only want to use vitamin D3 (cholecalciferol).
How much is needed?
Experts disagree on how much vitamin D we need in our blood to be healthy. The Institute of Medicine recommends that most Americans need no more than 600 international units (IU) of vitamin D a day. People 71 and older may need 800 IU, it says
As per Dr.Mercola, based on the most recent research by GrassrootsHealth—an organization that has greatly contributed to the current knowledge on vitamin D through their D* Action Study—it appears as though most adults need about 8,000 IU's of vitamin D a day in order to get their serum levels above 40 ng/ml. This is significantly higher than previous vitamin D recommendations!
For children, many experts agree they need about 35 IU's of vitamin D per pound of body weight.
What are the potential harms of excess vitamin D supplements?
Very high doses of vitamin D can cause extremely high levels of calcium in your blood, which can lead to heart rhythm problems, kidney stones and damage, and severe muscle weakness. This calcium excess usually happens if you take 40,000 IU per day for a couple of months or longer, or take a very large one-time dose.