Should you take Vitamin D if you have cancer?

June 11, 2012 by
Guest blog   3 Comments

Some 18 different cancers occur more frequently in people who have low levels of vitamin D, the sunshine vitamin. In 12 of these cancers the evidence is very strong establishing a case that insufficient vitamin D actually causes the disease.

We know that smoking causes lung cancer, but lung cancer seems to progress faster in people whose vitamin D is low. For example, people living in Scotland, where they get much less sun than in southern England, die sooner after lung cancer is diagnosed than people in England. People with dark skin make vitamin D much more slowly than people with white skin and so their vitamin D levels are lower and they are at greater risk of cancer. Dark skinned women with breast cancer are likely to have earlier recurrence of disease and die sooner than white women with the disease.

Vitamin D is necessary for the differentiation of cells into different tissue types. When vitamin D is insufficient the cells may become arrested at an intermediate stage which then develops into a cancer cell. Such malignant cells would normally die by a process called apoptosis, or programmed cell death, but this process is arrested when there is insufficient vitamin D. And so when vitamin D is low the risk of cancer is greatly increased.

These laboratory findings are not in any doubt. They appear to apply to most, probably all, cells suggesting that vitamin D may have a role in many, perhaps all, cancers. Several clinical trials are in progress to test this in various cancers. These trials are all financed by non-commercial academic funds because vitamin D cannot be patented and so drug companies are not interested in undertaking trials which take years and cost millions of pounds.

The prestigious International Agency for Research on Cancer in Lyons recognised in 2008 that insufficient vitamin D is an important cause of bowel cancer. At that time evidence was not considered sufficient to implicate other cancers but it has been accumulating rapidly and insufficient vitamin D is now widely suspected to be a major factor causing cancer.

A recent clinical trial at the Medical University of South Carolina demonstrates the promise of vitamin D for people with cancer. Some 50 patients with low risk prostate cancer took 4000 IUs (international units) of vitamin D a day over a period of a year and the activity of the tumours declined in half of them. Five patients showed no change. Without vitamin D the disease would have been expected to worsen.

If I take vitamin D now might it arrest or slow the growth of my cancer?

Yes it might. But despite much detailed research the latest information has not reached many oncologists. This is partly because, unlike a drug from a Pharma company, vitamin D is not actively promoted. Sadly many oncologists discourage their patients from taking vitamin D because they know little or nothing about it.

Vitamin D has few if any adverse effects and many benefits, apart from its probable effect in cancer, and so it makes sense to take it in the hope that it may improve your chances in fighting the disease. Benefits for muscle and bone, reduction of pain in arthritis, improving diabetes and increasing resistance to infectious disease make it worthwhile to take vitamin D regardless of cancer.

How much vitamin D should I take?

The dosages of vitamin D recommended in the past, and still often today, were based on the amount needed to cure rickets, the bone disease of children. Much larger amounts are needed to ensure optimum health. Almost everyone in UK has insufficient, sub-optimum levels of vitamin D and many suffer frank deficiency. This is because modern living keeps us indoors. Only a few people with outdoor jobs e.g. sports teachers, some builders and people with regular outdoor hobbies such as gardeners have a good level of vitamin D.

Unless you come into this category or take regular sunshine holidays then you are likely to have a low or very low level of vitamin D. This is because in theUKwe have a very cloudy sunless climate. Food is a poor source of vitamin D. It is not possible to get more than about 5% of the optimum from food – perhaps 10% if you regularly eat oily fish.

My suggestion is to take 5,000 IU of vitamin D a day for at least three months and then ask your doctor to test your vitamin D. If your blood level has reached more than 100 nmols (nanomoles) per litre than you can reduce your intake to say 4000 IU per day, if not continue and test again after another three months. Doctors interested in vitamin D and cancer generally recommend a level of 100 to 150 nmols per day.

I have been campaigning to tell people about the benefits of vitamin D for some eight years, and I have found that people often have difficulty in getting suitable vitamin D products that are good value and easy to take. So in the last year I decided to establish The Vitamin D Company and we produce a microtablet that is tasteless and can be swallowed very easily, crunched or just left in the mouth to disperse in saliva. It is suitable for vegetarians and all faiths and can be taken by all ages including small children. These vitamin D products are available online from or by telephoning +44 (0) 7761379939.

But remember the sun is free – so enjoy it. If you get at least half an hour of full sun on bare shoulders, arms and legs three or four times a week in the middle of the day, in summer, you need not take any vitamin D until the weather changes or the days shorten and the sun is low in the sky, below an angle of 45 degrees.

For optimum sun exposure wear shorts, short skirt without tights or off the shoulder vests whenever you can. When suitable, remove as much clothing as you decently can and bask in the sun. So long as you do not burn there is no serious risk of skin cancer. If you are not used to the sun a few minutes may be all you can tolerate to begin with, but gradually increase the time you spend in the sun. Sun cream stops the skin from making vitamin D and so do not put it on until you have had as much sun as you can comfortably tolerate without burning – then it is best simply to move into the shade and chill out.

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3 Comments on "Should you take Vitamin D if you have cancer?"

  1. charlotte ellis June 12, 2012 at 6:11 pm · Reply

    so that should mean that people in sunny climes get less cancer. Is that supported by statistics?

  2. Oliver Gillie June 13, 2012 at 9:13 am · Reply

    Yes – a very interesting question. There is a great deal of variation in illness particualrly cancer that appears to be linked to variation in sunlight with latitude. This is what William Grant says in a recent article about differences within the US. “The results of the current study demonstrate that much of the geographic variation in cancer mortality rates in the U.S. can be attributed to
    variations in solar UV-B radiation exposure. Thus, many lives could be extended
    through increased careful exposure to solar UV-B radiation and more safely,
    vitamin D3 supplementation, especially in nonsummer months. Cancer 2002;94:
    1867–75. © 2002 American Cancer Society.”

    There are also differences between England and Scotland e.g. more bowel cancer in Scotland. I have written a peer-reviwed article about this available at ANTICANCER RESEARCH 32: 237-248 (2012) The Scots’ Paradox: Can Sun Exposure, or Lack of it, Explain Major Paradoxes in Epidemiology? This is because Scotland is further north and has much more cloud giving it something like two thirds the sun exposure of southern England.

  3. charlotte ellis June 13, 2012 at 11:28 am · Reply

    strangely enough, my poor late brother who died of lung cancer a few years ago, had an immense longing for sunshine just before he died. He was planning to take a long holiday on one of the Greek islands.

    have also heard that some people just before dying of cancer and lying in bed want to let as much light and sunshine into their bedrooms as possible.

    Could all that be related to vitamine D?

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