Vitamin D and Cancer

Can Vitamin D reduce risk of having a Cancer?


There are some nutritional risk reduction strategies you can do to decrease your chance of development of cancer and lower the incidence of cancer returning. One of those strategies is including Vitamin D in your diet.

What do we know about Vitamin D and should we use it?

The European Prospective Investigation into Cancer and Nutrition (EPIC) study showed that low levels of vitamin D are linked with increased risk of colon cancer. EPIC study is one of the largest European studies in the world, with more than half a million participants recruited across 10 European countries and followed for almost fifteen years.

It is worth to acknowledge that optimal level of vitamin D is unknown, and we don’t have a study that shows us that consumption of dietary vitamin D is associated with reduced risk.

The problem with the studies that showed no benefit to our health was that researchers used low dose of vitamin D supplementation. More data suggests that higher doses are needed.

Patients with Stage IV colon cancer that have higher levels of vitamin D at baseline, have higher survival outcomes not dependent on treatment, but it’s unknown whether aggressive vitamin D replacement can improve outcomes. (Wesa Asco 2010)

Women with early hormone receptor positive breast cancer, that receive AI (Aromatase Inhibitors) by taking vitamin D and Calcium, have markedly decreased risk of bone loss.

NCI (National Caner Institute), does not recommend, nor is against using vitamin D supplements.

So, What Is Vitamin D?

It is a fat–soluble pro-hormone. Substance that usually has little hormonal activity by itself, but our bodies can turn it into hormones.

There are two major forms of vitamin D.

  1. D2 (ergocalciferol), which is made naturally by plants
  2. D3 (cholecalciferol), which is:
  • Vitamin with hormone like action
  • Controls calcium, phosphorus, bone metabolism, and neuromuscular function.
  • It is a vitamin we can manufacture from sunlight.
  • New research shows that vitamin D3 deficiency is linked with depression, back pain, cancer (breast, prostate, colon, pancreas), insulin resistance, impaired immunity, macular degeneration, and fatigue.

As mentioned above, our body makes Vitamin D3 naturally, when skin is exposed to ultraviolet radiation in sunlight. Both forms then are converted to 25-hydroxyvitamin D in the liver, then this form travels through the blood to kidneys and it is further modified to 1,25-dihydroxyvitamin D (calcitriol) the active form of Vitamin D in the body.

The best and most accurate method of evaluating person’s Vitamin D status is to measure the level of 25-hydroxyvitamin D in the blood (the form is converted in liver and released in blood)


Where can we get Vitamin D?


  1. Sun exposure – most people don’t have sufficient sun exposure, and many studies point out that those who live in hot climates with lot of sun exposure, still carry high incidence of vitamin D deficiency.
  2. Dietary sources of Vitamin D are: fatty fish, fish liver oil, and eggs.
  3. Some foods are fortified with Vitamin D, such as milk, juices and breakfast cereals.
  4. Supplements.


What is Vitamin D role in our body?

Major role of vitamin D is to help the use calcium and phosphorus to make strong bones and teeth.

Vitamin D deficiency can cause weakening of the bones that is called rickets in children and osteomalacia in adults.

Too much vitamin D can cause toxic effects, and can be harmful since it increases calcium levels and can lead to calcinosis (deposition of calcium salts in soft tissues, such as kidneys, heart, and or lungs).

Average safe intake level of vitamin D is 100 ug per day (4000 IU per day).

It is also important to note that too much sun exposure will not lead to vitamin D toxicity. 


Studies and Research

Some early epidemiologic research showed lower incidence of certain cancers and cancer death among individuals living in southern latitudes. Researches hypothesized the variation in vitamin D levels might account for this association.

Studies of cancer cells in mice, showed that vitamin D can prevent the development of cancer by decreasing cancer cell growth, stimulating cell death (apoptosis), and reducing tumor blood vessel formation (angiogenesis) 


Is there evidence that vitamin D can help reduce the risk of cancer in people?

The studies overall are inconsistent. The reason for that is, the level of vitamin D measured in the blood at a single point in time (as in most studies) may not reflect a person’s true vitamin D status.

Also, dietary studies do not account for vitamin D made in the skin from sunlight exposure.

It is possible that people with higher vitamin D intakes or blood levels are more likely to have other healthy behaviors. It may be one of these other behaviors, rather than vitamin D intake, that influences cancer risk.

Overall, all the studies to date that we have used low doses of vitamin D (400 IU per day) did not show any benefit in cancer prevention. We now know that this might not be sufficient vitamin D dose per day to see any reduction in cancer. 


What is the future for vitamin D?

At present researchers are conducting few phase 1 trials to establish and determine what dose of vitamin D may be useful for prevention of prostate, colorectal, lung and breast cancers.

VITAL TRIAL – (vitamin D and Omega-3 Trail) is actively recruiting patients and it will examine whether vitamin D supplementation can prevent the development of a variety of cancer types in healthy older men and women. This trial is expected to recruit 20,000 participants and be complete in June 2016.