November 26, 2022

Vitamin D is found in many dietary sources such as fish, eggs, fortified milk, and cod liver oil. The sun also contributes significantly to the daily production of vitamin D, and as little as 10 minutes of exposure is thought to be enough to prevent deficiencies. The term “vitamin D” refers to several different forms of this vitamin

Two forms of Vitamin D are important in humans: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D2 is synthesized by plants. Vitamin D3 is synthesized by humans in the skin when it is exposed to ultraviolet-B (UVB) rays from sunlight. Foods may be fortified with vitamin D2 or D3.

Vitamin D Requirements and Deficiency

vitamin dThe major biologic function of vitamin D is to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones.

Recently, research also suggests vitamin D may provide protection from osteoporosis, hypertension (high blood pressure), cancer, and several autoimmune diseases.

Vitamin D helps your body absorb calcium, which your bones need to grow. A lack of vitamin D can lead to bone diseases such as osteoporosis  or rickets. Vitamin D also has a role in your nerve, muscle, and immune systems.

If you are concerned that you are deficient in Vitamin D then a blood test can be done which measures Serum 25-Hydroxy vitamin D levels.

A Serum Hydroxy vitamin D level of 10 ng/mL is low, a level of 15 ng/mL is adequate and a level of 200 ng/mL is potentially toxic.

Causes of Vitamin D deficiency

The primary way that people become deficient in Vitamin D is by not getting enough sun or by having the body block the creation of Vitamin D (Did you know that your body creates it’s own Vitamin D?).

Pregnant women or women that are breastfeeding as well as people that wear a veil or other bodycovering outside as well as people taking carbamezepine, phenytoin, primidone or barbiturates are the most at risk of being low in Vitamin D.

Signs of Vitamin D deficiency

There are a few signs of vitamin D deficiency, mostly a sense of tiredness and muscle soreness or weakness and bone and joint soreness are the most common.

But in kids low Vitamin D can manifest as severe athsma as recent research has found. And also in kids it is critical to find this deficiency as it can lead to bad bones and late teeth as well as soft bone tissue, and we all know how much kids want to run around and play!

Rickets and osteomalacia are classic vitamin D deficiency diseases. In children, vitamin D deficiency causes rickets, which results in skeletal deformities. In adults, vitamin D deficiency can lead to osteomalacia, which results in muscular weakness in addition to weak bones.

Populations who may be at a high risk for vitamin D deficiencies include the elderly, obese individuals, exclusively breastfed infants, and those who have limited sun exposure. Also, individuals who have fat malabsorption syndromes (e.g., cystic fibrosis) or inflammatory bowel disease (e.g., Crohn’s disease) are at risk.

How to Get The Vitamin D That You Need

You can get vitamin D in three ways: through your skin, from your diet, and from supplements. Your body forms Vitamin D naturally after exposure to sunlight. However, too much sun exposure can lead to skin aging and skin cancer. So many people try to get their vitamin D from other sources such as food and Vitamin D supplements. You need to get anywhere between 200IU to 600IU of Vitamin D a day with the amount increasing as we age.

Vitamin D-rich foods include egg yolks, saltwater fish, and liver. Some other foods, like milk and cereal, often have added vitamin D supplement for a healthier body.

You can also take vitamin D supplements. Check with your health care provider to see how much you should take. People who might need extra vitamin D include

  • Seniors
  • Breastfed infant
  • People with dark skin
  • People with certain conditions, such as liver diseases, cystic fibrosis and Crohn’s disease
  • People who are obese or have had gastric bypass surgery

Foods high in Vitamin D

Cod liver oil, 1 tablespoon1,360
Salmon (sockeye), cooked, 3 ounces794
Mackerel, cooked, 3 ounces388
Tuna fish, canned in water, 3 ounces154
Milk, nonfat, reduced fat, and whole115
Orange juice fortified with vitamin D, 1 cup100
Yogurt, fortified, 6 ounces80
Margarine, fortified, 1 tablespoon60
Sardines, canned in oil, drained, 2 sardines46
Liver, beef, cooked, 3.5 ounces46
Ready-to-eat cereal, fortified40
Egg, 1 whole (vitamin D is found in yolk)25
Cheese, Swiss, 1 ounce6

In a not very scientific survey I have personally found that many women are very deficient in Vitamin D. My wife and some of her friends have had to supplement a lot of Vitamin D just to try to catch up

5 thoughts on “Vitamin D Requirements, Deficiency, and Supplementation

  1. Thank you for the good writeup. It in reality was once a leisure account it. Glance complicated to more delivered agreeable from you! However, how can we be in contact?

  2. Thanks for explaining that your body naturally produces vitamin D when exposed to sunlight, many people are unaware of this fact. It’s also important to note that, while many people take vitamin D supplements because they are deficient, an excessive amount of Vitamin D is actually toxic. If you are taking a vitamin D supplement you should get your levels checked periodically! http://www.mayoclinic.com/health/vitamin-d-toxicity/AN02008

  3. Thanks for the great information. My doctor recently advised me to get more vitamin D and now I know more about it.

  4. If you lay near naked in the midday sun for a few minutes without burning your skin should make between 10,000 and 20,000iu of vitamin D3.

    These are the levels of intake that NATURALLY human DNA evolved to work best with. Living outdoors, hairless, with pale skinned bodies enabled humans to survive away from the tropics because it allowed the body to store vitamin D3 to enable them to survive the winter. Humans only begin to store vitamin d after basic daily needs have been met and that’s around 40ng/ml. Only above 50ng/ml do we have significant amounts of D3 stored.

    In the most extreme north the Inuit survived by fermenting high omega 3 and Vitamin D3 sources in holes underground to supply around 6000iu/daily through the diet and lichen grazing Deer, and insects and birds living on lichen also have higher vitamin D levels.

    In order to store vitamin D require roughly 1000iu/daily for each 25lbs you weigh. For human breast milk to flow vitamin D replete requires roughly 6400iu/daily. This only happens when 25(OH)D is around 60ng/ml

    Virtually every cell in your body requires vitamin D3. Maintaining a stored reserve of vitamin D3 is like having a reserve of cash in an instant access savings account. Very helpful when under stress.

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