Research suggests that there is a link between low levels of vitamin D and an increased breast cancer risk for women.
What’s Vitamin D?
Vitamin D is a nutrient that helps the body absorb calcium, and as a result, it plays an important role in bone health and the prevention of osteoporosis. The neat thing about vitamin D is that the nutrient gets activated when the body is exposed to sunlight. In fact, the sun is the most potent form of the nutrient, although you can get it from other sources.
How to Get Enough Vitamin D
The most common means of getting enough vitamin D is direct sun exposure. Depending on your skin tone (people with darker skin tones need more vitamin D) most people need 15 minutes of direct sunlight during peak hours, three times per week. While it is impossible to overdose on vitamin D from the sun, getting too much sunshine does increase your risk of developing skin cancer. So it’s a delicate, albeit important, balance.
You can also get vitamin D from foods that are rich in the nutrient including:
- Fortified milk
- Fortified nondairy milk
- Fortified yogurt
- Steelhead trout
The Link Between Breast Cancer and Vitamin D
According to Breastcancer.org, research suggests that women with low levels of vitamin D have a higher risk of breast cancer because the nutrient may play a role in normalizing breast cancer cells. Vitamin D receptors, found on the surface of breast tissue, bind with the nutrient. This can cause breast cancer cells to stop growing and die.
One study, published in the April 2016 issue of Endocrinology, found an association between expression of ID1–an oncogene associated with tumor growth in breast cancer–and low levels of vitamin D. The study also found that mice injected with tumor cells and fed a diet low in vitamin D, were more likely to develop breast cancer.
Another study, published in the February 2006 issue of the American Journal of Public Health, found that breast cancer death rates seemed to be higher in places with low winter sunlight levels. What’s more, women exposed to more vitamin D than necessary had significantly lower risks of breast cancer and women with the lowest vitamin D levels had a five times higher risk of breast cancer than those with the highest rates.
Should You Supplement Vitamin D?
The National Academy of Sciences recommended a vitamin D intake of 200 IUs daily for those under 50 years old. The level increases to 400 IUs for those 51 to 70 years, and 600 IUs for those older than 71. Older adults need more, because the body doesn’t absorb it as well.
Other studies have shown that far too many of us are deficient because we should actually be taking as much as 7000 to 8000 IUs to get enough vitamin D into the bloodstream, especially in northern parts of the country that don’t get enough sun exposure in the winter. From March to November, no amount of solar exposure is enough in the Northeast or Midatlantic portions of the country. The Northwest provides some exposure during the winter months, but still not enough. If you live in parts of the country where you can’t get enough exposure, you might want to consider supplementation.
Potentially toxic overdose effects–which can include bone demineralization, hypercalcemia, hypercalciuria, or nephrocalcinosis with renal failure–are rare and usually only felt when levels are higher than 10,000 IUs daily.
In all, thousands of studies have shown that increasing the amount of vitamin D in the body is associated with a decreased risk of breast cancer as well as other forms of cancer. Long term studies have also shown the efficacy of moderate supplementation and reduced cancer rates. A simple blood test can tell you how much you require.
The Best Vitamin D Supplement
According to Consumer Reports, most vitamin D supplements actually contain what they’re supposed to, but prices vary significantly. Brands like NOW Vitamin D3, Whole Foods Brand, and Sundown all tested well and met quality criteria. This means they all met label claims and didn’t contain heavy metals.