Dangers of Vitamin D Deficiency

It is estimated that anywhere from 30 to 100 percent of Americans, depending upon their age and community living environments, are deficient in Vitamin D. More than half of all American children are vitamin deficient. Supposedly almost 75 percent of pregnant women are vitamin D deficient, predisposing their unborn children to all sorts of problems. Worldwide, it is estimated that the epidemic of vitamin D deficiency affects one billion people. In my practice over 80 percent of patients whose vitamin D levels I check are deficient.

No one is exactly sure why this is happening apart from the fact that we spend too much time indoors, and when we go out into the sun, we lather sunscreen on ourselves. I think it must be more than that. But whatever the reason, the reality is we have a major epidemic on our hands.

What diseases are associated with vitamin D deficiency?

Vitamin D deficiency has been shown to play a role in almost every major disease. This includes:

Osteoporosis and Osteopenia
17 varieties of Cancer (including breast, prostate and colon)
Heart disease
High blood pressure
Metabolic Syndrome and Diabetes
Autoimmune diseases
Multiple sclerosis
Rheumatoid arthritis
Infertility and PMS
Parkinson’s Disease
Depression and Seasonal Affective Disorder
Alzheimer’s Disease
Chronic fatigue syndrome
Chronic Pain
Periodontal disease

What is vitamin D?

Although it’s called a vitamin, vitamin D is really a hormone and not actually a vitamin. Our bodies cannot produce vitamins; we have to get them from dietary sources, whereas vitamin D is made in your body. It’s your body’s only source of calcitrol (activated vitamin D), the most potent steroid hormone in the body.

What does vitamin D do?

Like all steroid hormones, vitamin D is involved in making hundreds of enzymes and proteins, which are crucial for preserving health and preventing disease. It has the ability to interact and affect more than 2,000 genes in the body. It enhances muscle strength and builds bone. It has anti-inflammatory effects and bolsters the immune system. It helps the action of insulin and has anti-cancer activity. This is why vitamin D deficiency has been linked with so many of the diseases of modern society. Because of its vast array of benefits, maintaining optimal levels of D is essential for your health.

Where do I get vitamin D from?

Only about 10 percent of your vitamin D comes from diet, so it is nearly impossible to get adequate amounts of vitamin D from diet alone. The only two reliable sources of vitamin D are the sun and supplements.

Sunlight exposure is the only reliable way to generate vitamin D in your own body. Vitamin D is produced by your skin in response to exposure to ultraviolet radiation from the sun. In fact, this is such an efficient system that most of us make 20,000 units of vitamin D after only 20 minutes of summer sun without suntan lotion. That’s 100 times more than the government recommends per day! There must be a good reason why we make so much in so little time. But these rays cannot penetrate glass to generate vitamin D in your skin, so you don’t generate vitamin D when sitting behind a glass window, whether in your car or at home. Also sunscreens, even weak ones, almost completely block your body’s ability to generate vitamin D.

The other reliable source is supplements (read more about vitamin D supplements in part 3 of Dr. Frank’s FAQs Vitamin D series).

Stay tuned for part two of this series, “How to Tell if You Are Vitamin D Deficient,” which answers the following questions: What are the symptoms of vitamin D deficiency? What blood test should I have to check my vitamin D levels? The third and final part of this series addresses how to increase levels of vitamin D.


Angelica C
Angelica C5 months ago

Thank you for sharing this very interesting article. Concerning auto-immune diseases it's interesting to know how deficiencies may be impacting for example with Hashimoto (http://hypothyroidmom.com/92-of-hashimotos-patients-with-vitamin-d-deficiency/)

Su H.
sue H5 years ago

Surprising to many, that they are low in D3. You may be low despite what your doctor might say, they have rather low and outdated information, based on probably NO research. Everyone is different and many many people are low and do not know it.

Marie W.
Marie W5 years ago

Dr. Mercola has good Vit. D info all the time.

Bonnie M.
Bonnie M5 years ago

As someone pointed out- Vit. D supplements is just another additional drug. I do take Vit. D supp. Those of us who live through winter are desperately in need of sunshine. And yes, diet and nutrition would be very helpful.

Bonnie M.
Bonnie M5 years ago

As someone pointed out- Vit. D supplements is just another additional drug. I do take Vit. D supp. Those of us who live through winter are desperately in need of sunshine. And yes, diet and nutrition would be very helpful.

5 years ago

This site:
.... has a chart showing which foods have the most vitamin D....so I think you CAN get a decent dose of it from your food if you eat right!
Some of us cannot take supplements, and let's face it.... a lot of supplements that you take just give you expensive urine because the nutrients are not effectively assimilated and just pass right through your system.

A nutritionally balanced diet that has withstood the test of time is the Mediterranean diet....check it out.

Donna Hamilton
Donna Hamilton5 years ago

Thanks for the info.

Michelle J.
Michelle J.5 years ago

thank you. very interesting. I don't think enough is known about the benefits of vitamin D

Lika S.
Lika P5 years ago

Oh, great. Now I'll have to bring this article in to my doctor. Thanks for the info.

Pauline Goh
Pauline Goh5 years ago

Many people don't understand about the usage of Vt D. and this article do help a lot . Thanks