Vitamin D — Now What?

You've heard a lot about vitamin D, on this website and elsewhere. Now let me answer a few common questions.....

Can vitamin D cure cancer? We have no proof of this, so we can't say that vitamin D cures cancer. What we do know is that cancer occurs when cells go wild. They become abnormal for various reasons, and grow uncontrollably. Vitamin D affects many of the proteins that regulate how cells grow, multiply and change into different tissues in your body. While no studies have shown that vitamin D cures cancer, a few suggest that vitamin D may have a protective effect against colon cancer. Now that you know some of the important roles of vitamin D, would you rather your level was higher or lower?

Does vitamin D prevent dementia? A few studies suggest that lower vitamin D levels are associated with poorer cognitive function and a higher risk of Alzheimer's Disease. People with levels below 25 nmol/L had more difficulty planning, organizing, and prioritizing. I won't tell you that taking vitamin D will prevent or cure dementia. I can say that many of my vitamin D deficient patients reported headaches and feeling that their brains were in a fog. Those symptoms gradually went away as their vitamin D levels increased.

Can your vitamin D level be too high? Yes, very high vitamin D levels can be harmful. Symptoms include heart arrhythmias, weight loss, anorexia, and frequent urination. Vitamin D toxicity can raise calcium blood levels. All that calcium will then sit in your blood vessels, the vessel walls, and other body tissues. This can damage the blood vessels, heart, and kidneys. It can increase the risk of kidney stones.

Your skin is able to regulate vitamin D production from the sun, so high sun exposure does not cause vitamin D toxicity. (Of course it does increase your risk of getting skin cancer, so make sure not to overdo it. And use sunscreen.) As I pointed out in a past newsletter, it is quite difficult to take in enough vitamin D from food to be harmful. Toxicity is most likely to be caused by too much vitamin D supplementation. Even that is not easy.

Several reports indicate that you would have to take at least 10,000 IU daily for a prolonged period, and have blood levels of 500 nmol/L or more. Still, there is not enough information yet concerning exact dosages and toxic levels. For now, avoid 25-hydroxyvitamin D blood levels above 125 nmol/L. Most labs report levels up to 100 nmol/L as acceptable, so following that guideline with your doctor should help you avoid toxicity and harmful effects.

Here's another thing to consider: vitamin D supplements can interact with medications. Steroids like prednisone can decrease calcium absorption and interfere with vitamin D metabolism. This contributes to the osteoporosis and bone loss we see when people take steroids for a long time.

Some weight loss drugs, (eg. alli and Xenical), and cholestyramine, which lower cholesterol, reduce the absorption of fat. Vitamin D is a fat-soluble vitamin so it is best absorbed along with fat. Less of it will be absorbed if you are taking a drug that limits fat absorption. Some drugs like Dilantin, (generic: phenytoin), and phenobarbital, which are used to treat seizures, increase the liver metabolism of many substances including vitamin D. This leads to faster vitamin D breakdown into an inactive form. It also results in reduced calcium absorption.

A few of you have contacted me asking what I recommend to my patients, what I tell my family to use, and what I take myself. And yes, I do take vitamin D. Many brands have been studied by independent laboratories, and most were found to be okay. They contained the stated amount of vitamin D. They did not contain excessive harmful substances. I have tried a few of them myself, and then recommended them to my family, friends and patients. Here are my favorites. They are well absorbed so in most people levels go up and symptoms go away relatively quickly. (Note that with vitamin D symptoms, "quickly" means a few weeks.)

Some of these brands may be available in stores. Some are only available online. To make it easy, you can click the links below and buy them at Amazon. As usual Amazon has some of the best prices. If you do go to Amazon, check the reviews and see what others had to say about the different products.

So for those who asked, and others who may be wondering, I am including the information below, but please first note the following:

  • Remember that vitamin D is a dietary supplement. Companies do NOT require approval by the FDA, (Federal Drug Administration), to manufacture it, or sell it.
  • Also remember that I am a doctor, but I AM NOT YOUR doctor. I cannot be personally responsible for your health based on this newsletter/website. Go and speak to your doctor. If you can't speak to your doctor, fire him or her, and get another doctor!
  • I cannot guarantee results if you use these products. Just know that I have used these myself, and they worked for me.
Life Extension Vitamin D3, 5000 IU, 60 Softgels

Life Extension Vitamin D3, 5000 IU, 60 Softgels    Life Extension is the vitamin D3 brand I recommend the most often. This is also the one my patients usually request when they come to my office. Make sure you need to take 5,000 IU. If you need less than 5,000 IU a day, you can take it once every several days. Or once a week. Or get a lower IU dose. 

Speak to your doctor!

And by the way, this is what I usually take. Get it at Amazon. Or order directly from Life Extension.


Maybe you prefer to chew your vitamin D3. These taste good. Just be aware that each chewable gummy vitamin is 1,000 IU so if you are supposed to take 5,000 IU daily you will need to chew 5 of these a day. (These are the ones I get for my teenagers. Every now and then I help myself to a few.)

Vitafusion Vitamin D3 Gummy Vitamins, 150 Count

And for those who prefer liquid, this has 2,000 IU per dropper.....

Liquid Vitamin D 3 - 2,000 IU per drop - 900 Servings - High Potency

and this one has 5,000 IU per dropper.....
NOW Foods Liquid Vitamin D-3 5000Iu/Dropper, 2 ounce

Every day.....Say NO To Stroke!

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