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What are the health benefits of vitamin D?

 vitamin D

vitamin D

The human body produces vitamin D in response to sunlight or it can be ingested from a dietary source. Research has revealed that this essential vitamin is crucial for healthy bones, and may also have anti-inflammatory effects. As illustrated below, recent research is finding that vitamin D deficiency is now more prevalent than ever.

Cortisol and inflammation

As has been highlighted in previous articles , the hormone cortisol has a role to play in the body's inflammatory response - a phenomenon that has become of increasing concern as the world becomes more and more inflamed. When cortisol increases, it upsets the micro-ecology of the cells in our bodies, symptoms that include skin rashes and rhinitis, joint pain (especially in those with fibromyalgia or rheumatoid arthritis), gastrointestinal (GI) symptoms like indigestion, skin disorders (acne), heart disease, diabetes and fibroids.

While there are several causes of chronic inflammation in the body, including gluten sensitivity and auto-immune disorders, the underlying cause of many cases is elevated cortisol levels. As a person ages and the adrenal glands become less efficient at producing cortisol, they must be supplemented with exogenous (from outside the body) sources to avoid deficiencies [1]. In some cases, this may manifest as severe fatigue.

Vitamin D - an anti-inflammatory

The hormone calcitriol (1,25 dihydroxy cholecalciferol), which is formed from vitamin D or can be ingested from dietary sources, has been shown to exert an anti-inflammatory effect on cells by inhibiting cytokine production [2]. This anti-inflammatory effect is mediated indirectly through vitamin D's effects on the immune system, but it has been shown in a recent study that calcitriol can also directly inhibit pro-inflammatory cytokines and protein tyrosine phosphorylation.

While the precise mechanism by which vitamin D leads to an anti-inflammatory effect is still unclear, several mechanisms have been proposed and are outlined below:

1. Vitamin D increases serum neutral parathyroid hormone (NPH)

In this study , researchers checked whether a dose of vitamin D could improve insulin sensitivity without increasing blood glucose levels in individuals suffering from type 2 diabetes. What they found was that the vitamin D dose induced a significant increase in serum NPH levels which may improve insulin sensitivity and glucose tolerance.

2. Vitamin D inhibits interleukin-1 (IL-1)

In this study , researchers looked at whether vitamin D can inhibit IL-1alpha and IL-1beta production in mouse macrophages. What they found was that 1,25(OH)2D3 inhibited IL-1alpha expression by approximately 50% and increased IL-10 levels by 3 to 7 fold. An earlier study also reported that 1,25(OH)2D3 inhibits LPS-induced TNFa production in murine macrophages .

3. Vitamin D may regulate macrophage activation via IL-10

A study has shown that 1,25(OH)2D3 regulates expression of the anti-inflammatory cytokine IL-10 (also known as IL-1 receptor accessory protein) in murine macrophages [3]. Another recent study has described vitamin D's ability to induce immune tolerance by regulating pro-inflammatory cytokines (IL1b and TNFa) in bone marrow derived cells [4].

Vitamin D deficiency - the new normal

As highlighted above, vitamin D deficiency is now well recognized as a major problem. In fact, deficiencies are becoming so common that there is currently a campaign to increase awareness about vitamin D and improve the wellbeing of both children and adults suffering from low levels. As reported in the New York Times:

"The Centers for Disease Control and Prevention estimates that 1 in 30 Americans has insufficient [vitamin D] levels . . . A recent study found that, among teenagers, vitamin D levels dropped by as much as 51 percent from 2007 to 2012. In affluent countries like the United States, calcium deficiency — which is tied to vitamin D deficiency — is twice as common in women as it is in men. But because most people do not supplement with vitamin D or get enough sun exposure," sunlight cannot account for this high prevalence of deficiencies.

"It is something that is definitely happening, and it's across the population, but there's a lot of debate about why," said Dr. Edward D. Gorham, an author of the study and a researcher at the University of Wisconsin.

Low levels in women

Dr. Gorham explained that researchers are trying to figure out how widespread vitamin D deficiency actually is, how it affects people and whether there is a threshold effect at which point low levels cause symptoms.

The study found that women had lower blood levels than men in all age groups, perhaps because they tend to have less muscle mass (which helps produce vitamin D), or because they wear long pants and sleeves when outside more often than men. The current recommended dose of vitamin D is 400 IU per day. But Dr. Gorham said that even if people began to take the recommended 3000 IU per day, it probably would not correct a deficiency once it had set in.

"You could get a 25-year-old patient with low levels who's never been tested and say, 'Here, take this for 2000 hours of sun exposure,' " he said. "But it might not change anything."

In an editorial accompanying the study, Dr. Peter A. H. Jones, a professor of clinical medicine and laboratory medicine at the University of California San Francisco, said, "If indeed we are in the midst of an epidemic of vitamin D deficiency, as suggested by many studies, then serious consideration must be given to increasing the recommendations for vitamin D intake."

"We need to look carefully at what constitutes a normal serum [vitamin] D level," he added. "My concern is that advocating for more sun exposure is unwise."


In light of the above scientific evidence showing that elevated cortisol levels may contribute to inflammation and skin disorders (and may also directly suppress the immune system), it would seem prudent to give all anti-inflammatory drugs a second look .

One would assume that if a drug is used to fight inflammation, it would be non-inflammatory. Yet anti-inflammatory drugs (NSAIDs) such as ibuprofen , aspirin , and naproxen may have the opposite effect due to their effects on the levels of hormones involved in inflammation. In fact, naproxen has been shown to directly stimulate pro-inflammatory cytokine production in isolated immune cells [5].

In light of the evidence above, it may make sense to avoid these drugs if at all possible. It is also important not to forget other anti-inflammatory nutrients like fish oil (which contains anti-inflammatory omega 3 fatty acids), curcumin , and resveratrol . 

health benefits of vitamin D

Vitamin D sources:

Sunlight: Roughly 15 to 20 minutes of sun exposure between 10 am and 3 pm. (without sunscreen) can produce 10,000-20,000 iu of vitamin D!

Dark meat fish: roughly 500 iu of vitamin D per 6 oz serving

Egg Yolk: roughly 100 iu per egg yolk

Cod liver oil: roughly 400 IU per teaspoon

Granola bar with added Vitamin D: look for one that is fortified with 10 - 30% of the daily value. One with more than the DV is preferred so that you are consuming higher levels of this critical nutrient.

Vitamin D3 supplements: There are numerous vitamin D3 products available from vitamin manufacturers. They range from multivitamins to single ingredient supplements like cod liver oil, fish oil, and calcium. Here is a list of some of the various D3 formulations available:

• USP Fortified Cod Liver Oil - 1 gram contains 800-1000 IU of Vitamin D2 (cholecalciferol).

• Carlson Labs - Carlson's Harvest Blend - 500 iu per gram.

• Carlson Labs Harvest Blend™ with 25% more Vitamin D3 than the supplement listed above - 500 iu per gram.

• Carlson Labs Triple Strength Harvest Blend™ - 500 iu per gram.

• Carlson Labs Super Strenth® - 1000 IU per capsule.

• Solgar Vitamin D-3 softgel with natural d-alpha tocopherol (as preservative) - 100 IU per softgel.

• Nature's Own Pure Encapsulations Sunflower Seed Oil with added Fortified Vitamin D2 - 50:1 blend of sunflower oil and cholecalciferol (cholecalciferol).

• Solgar Vitamin D3/Krill Oil Complex with added calcium ascorbate also contains 10 mg coenzyme Q10 and .2 mg selenium per serving. Each serving contains 100 IU of vitamin D3.

• Nature's Plus calcium & d vitamin with extra vitamin K2 - 100 IU per tablet and a broad spectrum of nutrients & phytonutrients.

• Carlson Labs Vitamin K2 as MK-7 - 100 mcg.

• Carlson Labs Vitamin K2 as MK-4 - 60 mcg.

• Carlson Labs Vitamin D with natural vitamin K2 as menaquinone-4 (MK-4) and menaquinone-7 (MK-7) (a dual form of k2). 500 IU per capsule.

• Carlson Labs Vitamin D K2 with added vitamin K1, natto glycins, and natto phytosterols. - 500 iu per capsule.


2. van Beekvelt MC, de Vries JH, Schaafsma G, Arntz HR. Photocontact and photodermatoses after cosmetic treatment with psoralens for vitiligo: case reports and review of the literature. Br J Dermatol 1995;133:579–86

3. Katoulis AC, Kattar MM, Vougiouklakis GA. Photocarcinogenesis and photoimmunomodulation: the complexity of sunlight. J Eur Acad Dermatol Venereol 2007;21:475–81

4. Wang YZ, Yu XQ, Chang JH, Lo YC, Chen SC. et al. A prospective clinical study on the relationship between circulating corticosteroid and prognosis of patients with septic shock in an intensive care unit. Crit Care Med 2010;38:2909–16

5. Lummus ZL, Keating GM, Cook LA , Stamler J .


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