Vitamin D and cancer risk

   Measure your Vitamin D levels  |   Lifestyle after Cancer - the facts   | Your essential micro-nutrients

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This page describes the evidence for the benefits of vitamin D testing and explains why adequate vitamin D levels are important for health, the risk of cancer. It provides information and links to a reliable online service to enable you to order an oncologist approved laboratory Vitamin D test.

What is Vitamin D? 
Vitamin D is a fat solution essential vitamin which is converted to the active metabolite calciferol in the kidney. The three most common analogues of  vitamin D found in the body are D3 (cholecalciferol), D2 (ergocalciferol) and 25-hydroxy vitamin D. Deficiencies can lead to osteomalcia (rickets) in the young or osteoporosis in adults which causes bone collapse and increased risk of fracture. In addition, a deficiency of vitamin D has been linked to the fundamental processes of cancer

How do we acquire Vitamin D naturally?
Unlike other vitamins, essential minerals and fatty acids, vitamin D can be made in the skin following interaction with sunlight, in fact in an average population, over 80 per cent of the body’s Vitamin D actually comes from the skin following exposure to sunlight. This was the reason why Asian immigrants in the early seventies were vulnerable to the bone disease rickets. In 2009, a white teenage girl spontaneously fractured her wrist and was found to have severe vitamin D deficiency - she had stayed out of the sun or used total sun block since birth. Just 20 minutes of sun, to the body, is enough to increase serum vitamin D levels but be careful not to over expose your skin to sun damage or worse sun burn (the book Lifestyle after Cancer provides some great tips on how to maintain vitamin D levels whilst protecting the skin). Dietary sources include:

  • Oily fish and fish oils
  • Fresh green leafy vegetables
  • Gains
  • Nuts
  • Yeast products
  • Sun dried mushrooms and some cereals.
  • Vitamin D is commonly added to foods
  • Vitamin D and calcium supplements.

We do not have enough Vitamin D 
A study presented by Professor Thomas at the National Cancer Research Institute conference in 2011 found striking deficiencies in Vitamin D in UK populations. The poster presentation reported the vitamin D and omega 3 levels of individuals who had bought nutritional tests from the online service established by cancernet. Over 95% of participants had 25 hydroxy Vitamin D levels lower than 75 nmol/l. and 73% had levels less than 50nmol/l. (See full presentation). Numerous studies from across the world show they same levels of deficiencies including a study presented at the annual meeting of the American Society for Radiation Oncology, which reported more than three-fourths of people with a variety of cancers have low levels of vitamin D and the lowest levelswere associated with more advanced cancers. 

How vitamin D influences the cancer process?
Cancer cells exposed to calciferol in the laboratory have been shown to help key factors in cancer progression, namely; reduce proliferation, promote differentiation, inhibit invasion, prevent loss of adhesion and promote apoptosis. It has also be shown to interact with the androgen-signalling pathway in animals, inhibiting the production of factors which stimulate new blood vessels growing into cancers – stopping them growing (angiogenesis). Vitamin D is also necessary for a healthy immunity.

Excess Vitamin D
Like all chemicals, too much of a good thing can cause problems - taking Vitamin D supplements in excess has been known to increase blood calcium levels leading to nausea, mood changes, thirst, passing excess urine, dehydration and confusion. and the studies evaluating vitamin D supplements did not include serum measurements. Vitamin D excess cannot occur through diet or sun exposure it has only been reported via supplement intake. The best way to ensure adequate levels is to measure them.

Excess Vitamin D and Calcium Supplement
A large randomised trial was published in the  British Medical Journal in 20102 called the WHI CaD Study. It reported a seven year, randomised, placebo controlled trial of calcium and vitamin D (1g calcium and 400 IU vitamin D daily) in 36 282 community dwelling postmenopausal women. They observed that individuals who took calcium supplements with or without vitamin D had a slight increased risk of heart attacks.

Clinical studies link inadequate Vitamin D levels with cancer:
[1] An observational study from the USA showed that survivors of bowel cancer with regular exposure to sunlight had a lower incidence of subsequent relapse.

[2] An observational study from Australia showed evaluated people surviving the skin cancer melanoma. Obviously, as the risk of this disease increases with sun-burning patients are told to keep out of the sun afterwards. However the study demonstrated that those patients who ignored this advice and continued to have regular sun exposure actually had a lower risk of the melanoma spreading to another part of the body.

[3] An  observational evaluation of men with jobs involving exposure to high levels of sunlight found that they were less likely to develop kidney cancer than those with little or no sunlight exposure at work. More specifically, the study appearing in the journal “Cancer” showed men with the highest level of work-related exposure to sunlight were 24 percent to 38 percent less likely to have kidney cancer than other men.

[4] A reported in the Journal of Clinical Oncology evaluated 18 studies of over 10,000 people to show that people with the highest vitamin D blood levels had up to 33% lower risk of colon cancer, compared to those with the lowest. Researchers noted that vitamin D deficiency is a problem in industrialized nations, and as many as 58% of adults or adolescents in the US could be deficient in vitamin D.

[5] The American Society of Breast Surgeons reported that breast cancer patients with low levels of vitamin D had more aggressive tumors and poorer outcomes.  Researchers tracked 155 women who had surgery for breast cancer between January 2009 and September 2010." They found an association between low vitamin D levels (less than 32 milligrams per milliliter of blood) and poor scores on every major biological marker used to predict a breast cancer patient's outcome.

[6] A Systematic Review of Prospective Studies  published in the JCO (Ma et al 2011 29:3775-3782 ) evaluated nine studies which analysed Vitamin D intake and serum blood levels of 25-hydroxyvitamin D [25(OH)D] which covered 1,000,000 participants from several countries. The pooled RRs of colorectal cancer for the highest versus lowest categories of vitamin D intake and blood 25(OH)D levels were 0.88 (95% CI, 0.80 to 0.96) and 0.67 (95% CI, 0.54 to 0.80), respectively. There was no heterogeneity among studies of vitamin D intake (P = .19) or among studies of blood 25(OH)D levels (P = .96). A 10 ng/mL increment in blood 25(OH)D level conferred an RR of 0.74 (95% CI, 0.63 to 0.89). They concluded that Vitamin D intake and blood 25(OH)D levels were inversely associated with the risk of colorectal cancer.


[7] A word of warning - An analysis of data on 3,223 patients found those with the highest amounts of vitamin D from sun exposure had a 60 percent greater risk of developing the most common form of skin cancer (Basal cell Carcinoma) than those with lowest levels. This study tells us that too much sun, particularly burning will still increase the risk of skin cancers despite adequate vitamin D levels.

[8] Increased risks for all-cause mortality and death from cancer and cardiovascular disease associated with low vitamin D levels registered a weak, non-significant trends in a large prospective study, according to a study in the American Journal of Clinical Nutrition. The analysis did reveal one near-significant association, however: Women with normal waist circumference, defined as 35 inches or less, and low [25-hydroxyvitamin D (25-OH-D)] levels were at nearly double the risk for all-cause mortality (HR 1.85, 95% CI 1.00 to 3.44), whereas those with larger waist measurements were not," leading researchers to suggest that body fat distribution may play an important role in the modulation of the effect of low vitamin D concentrations. 

Do vitamin D supplements help lower cancer risk?
It is very clear that a low vitamin D levels correlates with a higher risk of cancer or indeed more aggressive types. What is less clear is whether taking a supplement can prevent cancer or its recurrence.  One study involving people who had recovered from melanoma suggests vitamin D supplements may be helpful:

[1] A  reported of a study from Stanford University School of Medicine in the Journal of Clinical Oncology showed that taking a vitamin D and calcium supplement may help some women reduce their risk for developing melanoma. They analyzed medical data from roughly 36,000 women between the age 50 and 79, were randomized to either take both calcium (1,000 mg) and vitamin D3 (400 IUs) supplements or placebo, daily for seven years. The study team found that women who previously had non-melanoma skin cancer were 57% less likely to get melanoma, if they were in the calcium and vitamin D group.


[2] Not all studies point towards the benefits of vitamin D supplementation - A report  published in the New England Journal of Medicine reviewed three clinical trials using doses of vitamin D that ranged from 400 IU to 1,100 IU per day all found that D didn't make a difference in terms of cancer risk. In fact, most of the evidence for cancer prevention lies in observational studies that simply compare vitamin D levels with the incidence of cancer in a study population. They concluded that, it was difficult to ascertain if people with high levels of vitamin D received some protection from it or if some other factor, such as their genetic inheritance or lifestyle factor, was at play.


As a result of this an article other studies, testing for vitamin D levels, once uncommon, has skyrocketed since medical studies linked deficiencies to a variety of diseases, including cancer according to a story in USA Today.  The article notes that between 2006 and 2008, vitamin D testing increased by 74 percent and that manufacturers of vitamin D diagnostic tests have seen similar increases in demand. Article: 


How to order an oncologist approved test to measure your Vitamin D.

Step one; Click on the pay now link, below, to take you to the paypal site so you can securely pay with credit or debit card. You will receive a conformation email once payment has been accepted. 

Step Two; The laboratory will then send you a kit containing tubes for blood samples, packaging and an addressed envelope. (Please stop taking dietary supplements for at least 48 hours before the blood test)

Step three; You then have to go to your local blood taking facility to take the blood sample (usually your GP's practice or a phlebotomy room in your local hospital - some phlebotomy centres may charge a small fee for this).  After labeling the pots, immediately put them into the packaging and envelope provided and post as soon as possible. It would be best to do this earlier in the week so it doesn't reach the lab late on a Friday. You also have the option to visit the lab, in London, itself if you feel this would be easier (address will be enclosed in the literature).

Step four (your report); Professor Thomas will review your individual results, write your report and provide specific dietary and lifestyle advice relevant to your individual results. This may include advising more of some types of foods, less of other foods or, if necessary, taking specific supplements for a designated period of time. This report aims to  empower you with the knowledge to be able to optimise your nutritional balance to give you the best change of preventing or fighting cancer and other chronic diseases.

The vitamin D Profile 

This test will give you a complete break down of your Vitamin D profile. It measures the three most common analogues:
D3 (cholecalciferol  |  D2 (ergocalciferol)  |  25-hydroxy vitamin D
Cost:  £49.50

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