Vitamin D: Roles, Benefits, Forms, Serum Levels, Blood Tests

What is Vitamin D

Vitamin D belongs to a group of fat soluble vitamins. Chemically it is a steroid. But don’t worry, there are steroids that are good as well as bad for you. Vitamin D is the good guy.

You may have heard of steroid hormones in connection with bodybuilding. Vitamin D is different and has an important role in your body metabolism.

Vitamin D Roles, Functions and Benefits

Primary function of Vitamin D is absorption and metabolism of calcium as well as maintaining its healthy blood levels. Adequate amount of calcium is needed for healthy and strong bones.

Vitamin D also aids absorption and metabolism of phosphorus.

Apart from these it plays important role in protecting your genes. Adequate levels of Vitamin D will protect you on a genetic level from many civilization and chronic diseases like cancer, autoimmune, cardiovascular and infectious diseases, for example flu or colds.

Other roles of Vitamin D include: influencing cell growth (proliferation, differentiation, and apoptosis of cells), neuromuscular and immune function, inflammation processes, reducing asthma symptoms and regulating healthy body weight.

Some research indicated that Vitamin D helps protect brain function later in life with possible protective affects against Alzheimer and Parkinson diseases.

Forms and Synthesis of Vitamin D

Vitamin D exists in five different forms. We call them Vitamins D1, D2, D3, D4 and D5. The important forms for humans are D2 and D3.

Here is how it works and how one form changes to another:

Vitamin D1 – Chemically it is a molecular compound of ergocalciferol with lumisterol.

Vitamin D2 – Also called as ergocalciferol.

Plants, fungus and some simple animals are producing ergocalciferol from ergosterol after exposure to Ultraviolet (UV) radiation. It is believed that these organisms use it as a shield against the sun’s radiation. Vitamin D2 is not produced in humans, but can be consumed by humans and converted into other useful molecules.

Vitamin D3 – Chemical name is cholecalciferol and it is produced from 7-dehydrocholesterol.

This form is created in our skin after exposure to UV radiation, especially the UVB rays. Average exposure to sun needed to produce adequate levels of Vitamin D3 is approximately 10 to 15 minutes twice a week.

Exposed skin should be on face, hands, arms, alternatively on the back. Ideally you shouldn’t be having any sunscreen or at least not higher number than 3.

Vitamin D4 – Chemical name is 22-dihydroergocalciferol.

It is sometimes used by physicians as a supplement to treat some specific conditions. Example is tetany, which is described as involuntary contractions of the muscles.

Vitamin D5 – Chemical name is sitocalciferol and is synthetically produced from 7-dehydrositosterol. It is similar in structure to Vitamin D3.

However, it is less toxic in high doses. It can be therefore used more readily by doctors to treat some medical conditions associated with Vitamin D deficiencies.

Normal, Low and High Serum Levels of Vitamin D

Normal levels of Vitamin D in healthy people are in the range of 50 – 100 nmol/L or 20 – 40 ng/mL.

Low levels associated with deficiency symptoms are levels below 30 nmol/L (12 ng/mL respectively).

High blood (serum) levels with possible adverse effects start at about 150 nmol/L (60 ng/mL respectively)

Standard Vitamin D tests measure serum content of 25-hydroxyvitamin D (25OHD) in a sample of your blood.

Vitamin D Blood Tests

The best way to stay in a healthy range is to have regular moderate exposure to sun and consuming foods rich in Vitamin D. If you suspect that you are not getting enough of them or are experiencing some of the deficiency symptoms then it is recommended to take a Vitamin D blood test.

You have basically 3 options for having a test:

  1. Ask your doctor for a Vitamin D test. If your doctor is not happy to offer you this test or if your health insurance doesn’t cover it then read on about your other options.
  2. Contact your Local Blood Test Laboratory. Find out if they offer these tests without doctor’s referral. Some will be happy to do so for you. But there might also be few who refuse.
  3. Buy a Test and perform it at home. There are many tests available these days. You can even buy them over the counter in your local Pharmacy or Chemist. If they don’t have it, you can buy some online. Performing the test will require you to prick your finger, get the blood sample and mail it to the Laboratory. The Laboratory will then let you know the results.

If your intake from dietary sources are insufficient then we recommend this Vitamin D Supplement from Amazon.

One Handy Tip

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