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The Deets on D: Why This Vitamin Is Crucial to Our Health

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Hardly a day goes by without some groundbreaking news about vitamin D. Originally known for its crucial role in maintaining calcium levels for bone health, it’s rapidly becoming apparent that we’ve vastly underestimated vitamin D’s significant importance for our overall health and well-being. In short, judging by what I see in my practice, and speaking with colleagues around the country, it’s looking very much like we’re facing an epidemic of vitamin D deficiency, with potentially grave consequences. This vitamin D-FAQ will help bring you up to speed.

What diseases are associated with vitamin D deficiency?
Vitamin D deficiency has been shown to play a role in almost every major disease, including: seventeen varieties of cancer (including breast, prostate and colon), osteoporosis and osteopenia, heart disease, high blood pressure, obesity, diabetes, autoimmune diseases, multiple sclerosis, rheumatoid arthritis, infertility and PMS, Parkinson’s, depression, Alzheimer’s, and chronic fatigue syndrome.

What is vitamin D?
Although it’s called a vitamin, vitamin D is actually a hormone. Our bodies cannot produce vitamins; we get them from dietary sources, whereas hormones like vitamin D are made in our bodies. It’s our bodies’ 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 vitamin D is essential for our health.

Where do I get vitamin D?
The only two reliable sources of vitamin D are the sun and supplements. Vitamin D is produced by our skin in response to exposure to ultraviolet radiation from the sun. In fact, this is such an efficient system that most of us make approximately 20,000 units of vitamin D after only twenty minutes of summer sun without suntan lotion (or clothes!). That’s a hundred times more than the government recommends per day! Unfortunately, you do not generate vitamin D when sitting behind a glass window because these UV rays cannot penetrate glass. And sunscreens, even weak ones, almost completely block our bodies’ ability to generate vitamin D. I’m not suggesting you go bake in the sun with suntan oil or go to tanning salons. Repeated sunburns—in children and very fair-skinned people—have been linked to melanoma, but there’s no credible scientific evidence that moderate sun exposure causes it. All you need is a little common sense when heading outdoors; do it gradually, and always avoid sunburn. Note: Remember to take antioxidants when you sit in the sun, as these can help prevent skin cells from sun damage.

The other reliable source is vitamin D3 supplements (not vitamin D2—read on below). Only about 10 percent of vitamin D comes from our diet, so it’s nearly impossible to get adequate amounts of vitamin D from food.

What are the food sources of vitamin D?

  • Fish liver oils, such as cod liver oil.
  • Fatty wild fish, like mackerel, salmon, halibut, tuna, sardines, and herring.
  • Fortified milk, orange juice, and cereal.
  • Dried Shitake mushrooms.
  • Egg yolks.

But to get adequate amounts of vitamin D from food, you’d have to eat at least five servings of salmon a day or drink twenty cups of fortified milk.

My doctor told me to avoid the sun. What do you think?
All living things need sun; the key is balance. Too much sun exposure can cause melanoma and skin aging, while too little creates an inadequate production of vitamin D. The amount needed depends on the season, time of day, where you live, your skin pigmentation, and other factors. As a general rule, if you’re not vitamin-D deficient, about twenty minutes a day in the spring, summer and fall, on your face and arms or legs without sunscreen is adequate. It doesn’t matter which part of the body you expose to the sun. Many people want to protect their face, so just don’t put sunscreen on the other exposed parts for those twenty minutes. If you live north of 37 degrees latitude (an approximate line drawn horizontally connecting Norfolk, VA to San Francisco, CA), sunlight is not sufficient to create vitamin D in your skin in the winter months, even if you’re sitting in the sun in a bathing suit on a warm January day. The further you live from the equator, the longer exposure you need to the sun in order to generate vitamin D.

How much vitamin D should I supplement with?
Most important is that you take vitamin D3 (cholecalciferol), the active form of vitamin D. Do not take vitamin D2 as it’s not as biologically active or as effective or as safe as vitamin D3. And taking the right amount is crucial; most doctors tend to underdose. The current recommendations from the Food and Nutrition Board of the U.S. Institute of Medicine, from 200 to 600 IU a day depending on one’s age, are way too low. IU stands for “international unit” and acts as a measurement for vitamins and hormones. However, IU weight varies from substance to substance, so a 600 IU dose of vitamin D is not the same as a 600 IU dose of vitamin A. With that in mind, here are some guidelines:

  • I recommend 2,000–4,000 IU daily depending on age, weight, season, how much time is spent outdoors, where one lives, skin color, and obviously blood levels. In other words if you’re older, larger, living in the northern latitudes during the winter, are not getting sun and have dark skin, I recommend the higher maintenance dose.
  • If your blood level is 30–45 nanograms per milliliter, I recommend you correct it with 5,000 IU of vitamin D3 a day for three months under a doctor’s supervision and then recheck your blood levels.
  • If your blood level is less than 30 nanograms per milliliter, I recommend you correct it with 10,000 IU of vitamin D3 a day under a doctor’s supervision and then recheck your blood levels after three months. It takes a good six months usually to optimize your vitamin D levels if you’re deficient. Once this occurs, you can lower the dose to the maintenance dose of 2,000–4,000 IU a day.

What are the symptoms of vitamin D deficiency?
There is no clear pattern of symptoms. In fact, many people remain asymptomatic despite low levels. But here are some of the more common symptoms:

  • Fatigue
  • General muscle pain and weakness
  • Muscle cramps
  • Joint pain
  • Chronic pain
  • Weight gain
  • High blood pressure
  • Restless sleep
  • Poor concentration
  • Headaches
  • Bladder problems
  • Constipation or diarrhea

What about vitamin D toxicity?
It’s impossible to generate too much vitamin D in our bodies from sunlight exposure; our bodies will self-regulate and only generate what they need. Although very rare, it is possible to overdose and become toxic with supplementation, as vitamin D is a fat-soluble vitamin and is therefore stored in the body for longer periods. Therefore, if you’re taking 5,000 IU or more daily, you should have your blood levels monitored approximately every three months.

What blood test should I have to check my vitamin D levels?
The only blood test that can diagnose vitamin D deficiency is a 25-hydroxy vitamin D test. Unfortunately, some doctors are still ordering the wrong test: a 1,25-dihydroxy vitamin D. Your doctor should do the right test for you. Unfortunately, even some of the labs, in particular Qwest, have had problems with correct results, usually giving erroneously high results. If you don’t want to go through your doctor, the ZRT lab does a blood-spot test that you can order without going through a doctor.

What is the ideal blood level of 25-hydroxy vitamin D?
The current ranges for normal are 20 to 55 nanograms per milliliter. These are much too low! They may be fine if you want to prevent rickets or osteomalacia, but not for optimal health. The ideal range for optimal health is 50 to 80 nanograms per milliliter.

How often should I have a 25-hydroxy vitamin D blood test?
At least once a year, especially at the beginning of winter. If you’re supplementing, I suggest you monitor your vitamin D levels approximately every three months until you’re in the optimal range. If you’re taking high doses (10,000 IU a day) your doctor must also check your calcium, phosphorous, and parathyroid hormone levels every three months.

My doctor prescribed Drisdol at 50,000 IU per week. What is it?
Drisdol is a prescription of 50,000 IU tablets of vitamin D2 or ergocalciferol. Ergocalciferol is not vitamin D, but it is similar. D2 is not normally found in humans and most studies show it does not raise 25(OH)D levels as well as cholecalciferol or vitamin D3 does. If you’re vitamin D deficient, the best thing to do, is to take vitamin D3.

Can I take cod liver oil to get my vitamin D?
Although cod liver oil contains a fair amount of vitamin D, it also contains high amounts of vitamin A. Vitamin A antagonizes the action of vitamin D and can be toxic at high levels.

Why is there an epidemic of vitamin D deficiency?
Experts estimate 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 three-quarters of pregnant women are vitamin-D deficient, predisposing their unborn children to all sorts of problems. Worldwide, experts estimate 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 about the use of tanning beds to get my vitamin D?
I don’t recommend them because we don’t really know if they’re safe. Because the light sources vary with different tanning beds, it makes them unpredictable and possibly unsafe. In addition, most commercial tanning beds emit an unknown amount of EMFs (electromagnetic field rays) and because we’re so close to the actual bed, it may be an unnecessary high dose. Theoretically, both these problems could be overcome, but in reality, they usually aren’t.

By Dr. Frank Lipman, M.D. for Tonic


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