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Newsletter: Dr Cannell answers reader questions

Posted on: April 1, 2006   by  John Cannell, MD


This month, I will answer some interesting questions from readers.

1. Dear Dr. Cannell: I’ve been on antidepressants for years and have never been able to get off them. Last November, I started taking 5,000 units of vitamin D every day. By January, I was able to stop my Lexapro. I feel better than I have for twenty years. Has anyone proved that vitamin D helps depression? Thank you. Jacob, Santa Barbara, CA.

Dear Jacob: No, it has not. Although I’m glad you are feeling better, there are no studies in the literature showing vitamin D effectively treats major depression, only that it improves mood or well-being, an important difference. However, there are compelling reasons to think it might help major depression, reasons I reviewed on the website two years ago. When I have the time, I will update that information.1

Since my review, Dr. Reinhold Vieth found 4,000 units of cholecalciferol a day was better than 600 units in improving well-being in endocrinology outpatients. Two studies using 800 units a day to improve mood gave conflicting results, but neither were in patients with major depression. Lastly, low levels of vitamin D were associated with high depression scores in a recent Tromso study.2, 3, 4, 5

As a psychiatrist, I find vitamin 5,000 units of vitamin D a day cures some patients with major depression who have low vitamin D levels but has no effect on others. In the end, I predict vitamin D deficiency (levels less than 50 ng/ml) will be found to be one cause of major depression, but an important one.

2. Dear Dr. Cannell: What is the best way to get vitamin D in the winter if you don’t want to take pills? Beth, Chicago, Illinois.

Dear Beth: Until now, either you had to take frequent vacations down south, go to a sun tanning parlor, or buy an ultraviolet light. Recently a better option came on the market; Mercola makes a D light system. The main advantage is it has few damaging UVA rays, has peak UVB outputs in the range that optimally triggers vitamin D production in the skin, makes large amounts very quickly, and can be used at home. I hope that sun tanning parlors will soon add this light to their salons so customers can have a wider choice of lights.6

3. Dear Dr. Cannell: Is it true I can smoke if I keep my vitamin D levels up? Bill, Boca Raton, Florida.

Dear Bill: No, that is not true. What you may be referring to is the most amazing study on vitamin D recently released. Using NHANES III data, Drs. Black and Scragg discovered that vitamin D levels were strongly associated with pulmonary function (how well your lungs work). Who would have thought? They found that people with the highest vitamin D levels who had smoked had better pulmonary function than those with the lowest levels who had never smoked! That is, of two things that hurt your lungs (vitamin D deficiency and smoking) vitamin D deficiency may cause more damage than smoking! However, the study said nothing about lung cancer – so stop smoking.7

4. Dear Dr. Cannell: I’m confused about how much vitamin D I should take. The government says one thing but I’m reading in the newspapers and magazines that I should take much more. What kind of vitamin D should I take, what’s the right amount, and where should I get it? Angie, Los Angeles, California.

Dear Angie: Great question! The only vitamin D you should take is cholecalciferol. No one knows for sure how much you should take but the easy answer is 2,000 units a day. The government says 2,000 units a day is safe to take on your own, without being under a doctor’s care, and without getting blood tests. Two thousand units a day will do a lot of good. However, it may not be enough for some African Americans, the obese, the aged, and for people suffering from sunlight deprivation. The safest thing to do is to get a vitamin D level (25-hydroxy-vitamin D) two or three times a year and take enough to maintain your level around 50 ng/ml (125 nm/L) year around. Remember your highest natural level will be in the early fall and your lowest level in the early spring.

If you take more than 2,000 units a day, you should have blood levels done periodically. To my knowledge, no one has ever given 5,000 units of cholecalciferol a day for three or four years to see what happens to blood levels. We think it will be OK but I’m not sure. I take 5,000 units in the winter, 2,000 units in the early spring and late fall, and none in the late spring, summer, and early fall when I enjoy the sun. I maintain my levels around 50 ng/ml.

The best source of cholecalciferol (vitamin D) I found is Bio Tech Pharmacal, Inc. (479-443-9148 from 8:00 a.m. – 5:00 p.m. CST) a federally licensed and FDA approved manufacturer. They make a 1,000 (although it is not listed on their website yet), a 5,000, and a 50,000 IU capsule. The 50,000 IU capsule can definitely cause vitamin D toxicity, is meant for health care providers, and should never be taken on your own. Most health food stores sell 1,000 unit capsules of plain cholecalciferol.

5. Dear Dr. Cannell: My grandmother has had signs of early dementia for the last two years. I started giving her 5,000 units of vitamin D every day about six months ago. The results are amazing. Her memory is better, she no longer gets confused, and I can tell she feels better. She is on the way back to us! Is there any evidence that vitamin D can help dementia? Thanks for all you do. Lorenz, Attica, New York.

Dear Lorenz: There is no interventional evidence; that is, no one has given that amount of vitamin D to mildly demented patients to see if it helps. Remember, once the brain shrinks, as it does in dementia, vitamin D should have little effect. Important animal research recently showed activated vitamin D3 acts as a powerful anti-inflammatory agent and completely reverses the age-related increase in the inflammatory markers that accompany dementia, meaning they discovered the mechanism by which vitamin D may prevent dementia.8

At least three studies have incidentally found that demented patients have low vitamin D levels. The obvious explanation is that demented patients don’t go outside as much. However, Dr. Dhesi found associations between vitamin D and cognition within a narrow range of cognition, harder to explain by outdoor behavior. Dr. Flicker found the association, even after adjusting for outdoor exposure, suggesting causation.9, 10, 11

Recently the Australians showed that multiple areas of the human brain contain both the vitamin D receptor and the ability to activate vitamin D into the powerful steroid hormone, calcitriol. This means vitamin D therapy may have implications for a wide variety of neurological and psychiatric illnesses. I’m glad your grandmother is better but I’m not surprised. One on the doctors I work with noticed similar improvements with his mildly demented mother.12

6. Dear Dr. Cannell: Are you the “Lake Woebegone” general practitioner who practiced in West Virginia in the 1980’s and tried to reform testing in America’s public schools? Colton, Camp Creek, West Virginia.

Dear Colton: Yes, I am and say “hey” to everyone in Camp Creek. Unfortunately, the testing infrastructure in our schools remains corrupt and President Bush made it worse with No Child Left Behind testing. The Third Education Group Review recently asked me to “come out of retirement” and submit a paper on the current situation in America’s public schools.13

7. Dear Dr. Cannell: I noticed that my basketball game is a lot better after I started taking vitamin D. Have you heard anything like that? Jason, Richmond, Virginia.

Dear Jason: I’ve heard it from many of people; remember that activated vitamin D is a potent steroid hormone. I’ve never been a good athlete – and I’m still not – but my tennis game is clearly better since I’ve been maintaining my level at 50 ng/ml. The literature is actually quite convincing that vitamin D improves the athletic abilities of older people who are vitamin D deficient. That is, vitamin D makes them fall less, and improves their choice reaction time, muscle strength, percentage and area of type II (fast) muscle fibers, and balance. However, to date, no one has directly tested the theory by giving physiological amounts of vitamin D (5,000 units a day) to young vitamin D deficient athletes. I predict whomever does that study will be all over the news. Furthermore, idiopathic (which means the doctors are too idiotic to know why) low back pain is rampant among athletes, especially indoor athletes. There is good reason to think that many of them are vitamin D deficient. I’m not going to cite the references to any of this because I’m writing a paper. However, it looks as if levels of about 50 ng/ml will optimize athletic ability.

8. Dear Dr. Cannell: Who was R. Edgar Hope-Simpson? I loved your newsletter on vitamin D and the flu. Ed, Boston, Massachusetts.

Dear Ed: Dr. Hope-Simpson, one of my heroes, was an English general practitioner who became famous in 1965 after he single-handedly discovered the cause of shingles. It was one of the greatest discoveries by a GP in modern medical history.14

After that he dedicated his life to studying influenza. I believe he correctly predicted that vitamin D plays a major role in preventing influenza epidemics although he didn’t know it was vitamin D; he called it the “seasonal stimulus.”15

After reading Hope-Simpson and researching the topic, I wrote a newsletter about my theory: Pascal’s Wager Newsletter

If you talk to people who keep their levels around 50 ng/ml, they will tell you they just don’t get respiratory infections very often and if they do, they are mild. I believe the reason is simple: vitamin D dramatically increases the amount of naturally occurring antibiotics (antimicrobial proteins) in your lung and respiratory tract.16, 17, 18

I have personally given 50,000 unit capsules of vitamin D to patients in early stages of what appears to be influenza (1,000 units/kg per day for three days, so a 120 pound person would take 50,000 units a day for three days; a 240 pound person would take 100,000 units a day for three days) and found it either stops their illness or ameliorates it. I find it has less effect on people with well-established respiratory infections and I don’t understand why.

9. Dear Dr. Cannell: Why don’t you like cod liver oil? There are a lot of studies showing it helps. Thanks. Sue, Seattle, Washington.

Dear Sue: There are lots of studies showing cod liver oil helps lots of things. Did you know there are at least seven studies from the 1920’s and 30’s showing it reduces colds, flu, and absenteeism in both children and adults? Did you know there are two recent studies indicating it either helps prevent or ameliorates respiratory infections in children? Which one of the three nutrients in cod liver oil: vitamin A, vitamin D, or omega-3 (fish oil) fats is responsible, or is it two of them, or is it the three combined? We don’t know – at least I don’t.

I am leery of the vitamin A. Cod liver oil has anywhere from 5,000 to 15,000 units of preformed vitamin A in each tablespoon, sometimes more, besides the vitamin D and omega-3 fats. The question is what is the ideal amount and ideal combination of all three nutrients? The answer for vitamin D is becoming clearer: enough to get levels up to about 50 ng/ml year-around. Optimum omega-3 intakes are less clear and depend on the amount of omega-6 fats (most vegetable seed oils) in your diet. The answer for vitamin A is unclear, at least to me.

Vitamin A and vitamin D interact in unknown ways. Vitamin A protects against vitamin D toxicity and visa versa but we don’t know why. There is increasing evidence that some Americans, perhaps quite a few, are suffering from sub-clinical vitamin A toxicity, mainly from the preformed vitamin A in their multivitamin supplements.19

I am not convinced that because cod liver oil is “natural,” it is therefore good. Tsunamis and strychnine are natural. In fact, cod liver oil is a processed food and Paleolithic man didn’t drink it. There is evidence that at least one Paleolithic African women suffered severe vitamin A toxicity, probably from the liver she consumed. Chronic consumption of chicken liver caused vitamin A toxicity in twin girls.20, 21

A recent review of the literature found evidence that higher vitamin A levels are associated with bone problems. Women who consumed more than 15,000 units of vitamin A per day in food and supplements had a three and a half times higher risk for birth defects in their children than women who consumed less than 5,000 IU.22, 23

Vitamin A antagonizes the actions of vitamin D, probably at the receptor level, although that is not clear. The amount of vitamin A in one serving of liver antagonizes the rapid intestinal calcium response to physiological levels of vitamin D in man.24, 25

We just don’t know if large amounts of vitamin A (more than 5,000 IU per day) causes problems when consumed with a large amount of vitamin D, as would be the case in people consuming large amounts of cod liver oil. A very well-written and entertaining rebuttal to my cod liver oil position, which I presented to the Weston A. Price Foundation, was recently published by that same foundation. However, Dr. Noel Solomon – a vitamin A researcher who spoke at the same conference – also cautioned against high vitamin A intakes.

In the end, my natural conservatism wins out. More is not better. What was the diet we evolved on? I know my Paleolithic ancestors didn’t drink cod liver oil. Neither will I, unless my mother makes me, or until I have to choose between cod liver oil or nothing – and I don’t.

10. Dear Dr. Cannell: Is the upcoming conference on vitamin D OK for the general public or is it only for scientists? Travis, Missoula, Montana.

Dear Travis: I’m not a scientist but I wouldn’t miss it. Although the conference is designed for scientists, Dr. Tony Norman and Dr. Roger Bouillon – two world-renowned vitamin D researchers and the conference organizers – have included long sections the general public should find fascinating. You can look at the “Scientific Program” and decide for yourself. Scientists on the front line of the revolution (Reinhold Vieth, Robert Heaney, Ed Giovannucci, Bruce Hollis, Heike Bischoff-Ferrari and Susan Whiting) will all be speaking. The queen of sunphobics, Barbara Gilchrest, will be giving the Plenary Lecture; can you imagine? I wouldn’t miss her talk on a bet. You can always discover Victoria and enjoy the Fairmont Empress Hotel when the presentations are too technical.

11. Dr. Cannell: Who is responsible for the Vitamin D Council’s new website? It’s great. Geoffrey, Edinburgh, Scotland.

Dear Geoffrey: Ms. Dana Michelle Clark is working on it and doing a great job. Bill Sardi at Knowledge for Health sponsored her. Bill took pity on the Vitamin D Council’s dire financial condition and generously funded the improvements in our website. I hope to update the website’s content and add an e-book in the next few months.

2 Responses to Newsletter: Dr Cannell answers reader questions

  1. Rita and Misty

    Sometimes the oldest blogs here are the most interesting 😉 And I find this one extremely interesting. Hope others do as well. 🙂

  2. Yasir Mahmood

    I found it most interesting and informative

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