The Sunshine Vitamin-Vitamin D (The World’s Most Common Deficiency)
Home  / The Sunshine Vitamin-Vitamin D (The World’s Most Common Deficiency)
The Sunshine Vitamin-Vitamin D (The World’s Most Common Deficiency)
Home  / The Sunshine Vitamin-Vitamin D (The World’s Most Common Deficiency)


Vitamin D is a fat-soluble vitamin (mixes or dissolves in fat), which means it can be stored in body fat for an extended length of time.

Having enough Vitamin D has multiple roles in the body, helping to:

  • Maintain the health of bones and teeth.
  • Support the health of the immune system, brain, and nervous system.
  • Regulate insulin levels and aid diabetes
  • Support lung function and cardiovascular health.
  • Influence the expression of genes involved in cancer development.

Vitamins are nutrients that cannot be created by the body and therefore must be taken in through our diet. However, vitamin D can be synthesized by our body, as long as we get an adequate amount of UV light exposure (from the sun) on our skin.

Sun exposure on bare skin for 5-10 minutes 2-3 times per week allows most people to produce sufficient vitamin D, but vitamin D breaks down quite quickly, meaning that stores can run low. But due to modern office-based lifestyles, sun exposure on its own is no longer enough.

For instance, darker skin color and the use of sunscreen reduce the body’s ability to absorb the ultraviolet radiation B (UVB) rays from the sun needed to produce vitamin D. A sunscreen with sun protection factor (SPF) 30 can reduce the body’s ability to synthesize the vitamin by 95 percent.

Two main types of vitamin D
  • Vitamin D2 (ergocalciferol): Found in plant foods.
  • Vitamin D3 (cholecalciferol): Found in animals, like fatty fish and egg yolks.

Both are converted into the “active” type in the body when exposed to UV light from the sun.


One microgram of vitamin D is equal to 40 IU of vitamin D.

The recommended intakes of vitamin D throughout life:

  • Infants 0-12 months – 400 IU (10 mcg).
  • Children 1-18 years – 600 IU (15 mcg).
  • Adults to age 70 – 600 IU (15 mcg).
  • Adults over 70 – 800 IU (20 mcg).
  • Pregnant or lactating women – 600 IU (15 mcg).

The standard dose for vitamin D3 supplementation is 1,000‑2,000 IU (International Unit) per day, this is sufficient to meet the needs of most of the population.

The safe upper limit is said to be 4,000 IU (100 micrograms) per day.

Note:  It’s important to monitor regularly the blood levels of vitame D to ensure that the levels are as per recommended for different age groups and toxic levels are not attained


There are several commonly overlooked factors to consider before you supplement and while you supplement:

  • Vitamin D supplements should be taken daily with meals or a food source that contains fat.
  • Vitamin D supplements are known to interact with steroid medications, weight loss drugs and certain cholesterol-lowering drugs. These may inhibit the absorption of vitamin D.
  • Vitamin D and calcium supplementation seem to complement each other. This could be why combination treatment may be additionally beneficial in some aspects of health, including blood pressure and cancer risk.
  • Vitamin D may complement vitamin K2 supplementation as both share similar roles and mechanisms when it comes to heart and bone health.
  • Maintaining adequate magnesium levels also appears to be important for the function of vitamin D.

Remember that no nutrient acts in isolation, and no one supplement is a cure-all for your health problems. Supplements should be used as a tool to support a healthy diet and lifestyle, not replace it.

Vitamin D food sources

  • cod liver oil, 1 tablespoon: 1,360IU
  • herring, fresh, raw, 4 ounces: 1,056IU
  • swordfish, cooked, 4 ounces: 941IU
  • raw maitake mushrooms, 1 cup: 786IU
  • salmon, sockeye, cooked, 4 ounces: 596IU
  • sardines, canned, 4 ounces: 336IU
  • fortified skim milk, 1 cup: 120IU
  • tuna, canned in water, drained, 3 ounces: 68IU
  • egg, chicken, whole large: 44IU