Vitamin D help lower the risk of an occurrence or recurrence of breast cancer

Vitamin D: Not Just for Bones Anymore (for breast cancer survivors)

If awards were given out for vitamins, vitamin D would certainly win in the
popularity category. The darling of the medical and nutritional world for the past
several years, this hormonelike vitamin has a host of tasks: it helps regulate calcium
utilization, exerts a direct effect on both insulin and blood pressure, and helps
protect bone integrity. But we’re interested in its role in maintaining healthy
immunity and in normalizing cellular differentiation to help lower the risk of an
occurrence or recurrence of breast cancer.

Cell Differentiation

Differentiation is the process by which cells develop specialized characteristics.
As they mature, cells differentiate to take on specific roles in the body; for example,
a breast cell carries out its tasks once it is well differentiated. When cells are well
differentiated, they tend not to divide as quickly. To maintain good health, keeping
cells dividing at the appropriate rate is a top priority, because an overproliferation
of cells with damaged DNA can lead to cancer. Vitamin D inhibits this process of
overproliferation and stimulates healthy differentiation of cells (Holick 2004).

Immunity

Vitamin D is also a powerful immune system modulator; for example, we know
that vitamin D is essential for activating specialized immune cells known as T cells
(Rode von Essen et al. 2010). You’ll find more about T cells and other immune cells
in chapter 7.

Protection against Breast Cancer

In population studies, vitamin D also exhibits a strong association with lowering
breast cancer risk. For example, researchers who studied women in the first
National Health and Nutrition Examination Survey (NHANES I) found that sunlight
exposure and vitamin D intake were connected to a lower risk of breast cancer about
twenty years later in life (John et al. 1999).

In 2007, Cedric Garland, a prominent vitamin D researcher, published the results
of two case-control studies (studies that examine patients who already have a disease
to see if they have characteristics that differ from those of people without the
disease). Garland and his colleagues noted that women with a 25-hydroxyvitamin D
blood level of 52 nanograms per milliliter had half the chance of developing breast
cancer as women with D3 levels lower than 13 nanograms per milliliter.

Unfortunately, most American women are vitamin D deficient, a fact we have
seen repeatedly in our own practices. Women with the lowest levels tend to be older,
darker skinned, and heavier (vitamin D is stored in body fat, making it less readily
available for active use) (Arunabh et al. 2003). What’s more, women who use
sunscreen every day or go outside infrequently are also at a high risk of deficiency,
as are women on cholesterol-lowering drugs, since cholesterol is required for
vitamin D synthesis. The latitude where you live also affects your body’s ability to
convert sunlight into vitamin D. Many parts of the United States (particularly
latitudes north of the 37th parallel north) do not get sufficient ultraviolet B (UVB)
rays during the winter months due to the angle of the sun at this time, so
supplementing with vitamin D3 (cholecalciferol) during the winter may be
particularly critical.

Most, but not all, large-scale studies show that vitamin D plays a role in
lowering the risk of breast cancer. But having a reduced risk of a disease does not
guarantee that you will never get it. It merely lowers your chances. As summed up in
the American Journal of Public Health, “The majority of studies found a protective
relationship between sufficient vitamin D status and lower risk of cancer. The
evidence suggests that efforts to improve vitamin D status … could reduce cancer
incidence and mortality at low cost, with few or no adverse effects” (Garland et al.
2006).

Assessing Your Vitamin D Status

There are two forms of vitamin D found in blood: 25-hydroxyvitamin D
(25[OH]D) is the so-called “storage” form of D, while 1,25-hydroxyvitamin D is
considered the “active” form. Most experts agree that a blood test for 25(OH)D is
the best way to assess your vitamin D status, but not all agree on what ideal blood
levels are. So-called “healthy levels” can range from 40 nanograms per milliliter to
125 nanograms per milliliter, depending on whom you consult. Since each of us is
biochemically unique, we need different levels of vitamin D depending on age,
health status, vitamin A sufficiency, calcium status, and a host of other factors.

Our Perspective on Vitamin D

While adequate vitamin D levels are important to good health, it’s equally
important to guard against vitamin D toxicity and avoid its use in conjunction with
specific conditions. People with sarcoidosis, an autoimmune condition, should not
supplement with vitamin D, for example, because it can exacerbate this condition.

Generalized vitamin D toxicity can also cause major health difficulties for people
with liver or kidney issues. In addition, excessive D supplementation can boost
levels of blood calcium too high, a condition known as hypercalcemia. As with all
supplements, more is not necessarily better!

We support the judicious use of sunlight whenever possible and modest
supplementation of vitamin D3 (cholecalciferol), if needed, combined with regular
monitoring of your 25(OH)D level and serum calcium levels. A blood level of 50 to
80 nanograms per milliliter of 25(OH)D is, in our opinion, worth aiming for.
Always be sure to work with a knowledgeable health practitioner to optimize and
monitor your vitamin D levels.