Vitamin D was once only known for its role in bone formation but now is recognized for other functions. Vitamin D helps to boost the immune system and may help reduce disease risk and progression. Most recently, a study published in the Journal of the American Medical Association, found that women with breast cancer who had the highest blood levels of vitamin D (more than 25.10 ng/mL or greater) had statistically better survival than those with lower levels. Researchers also found that women with breast cancer who had serum vitamin D levels less than 16.75ng/mL had more advanced forms of breast cancer than those with higher levels. While there may be other confounding reasons as to the study results, such as the fact that people who take vitamin D may be more proactive about their health, etc, ask your doctor about your serum vitamin D level.
We normally create vitamin D from the sun’s UVB rays but there are many factors that affect our ability to do so. For example, at certain latitudes, when the earth is tilted away from the sun, we do not physically get the UVB rays that we need to make vitamin D. In New York, this amounts to somewhere between October and March. In addition wearing sunscreen (while important for skin cancer prevention) blocks UVB ray absorption. Vitamin D is considered a fat soluble vitamin and is better absorbed when taken with a meal. People with darker skin tones and older people have a more difficult time in synthesizing adequate amounts.
Unfortunately there are not many foods rich in vitamin D but see the list below for some ways to get started incorporating them into your diet. If needed, many people do supplement. To raise your serum level by 10ng/ml, you need to take 1000IU of vitamin D.
Foods high in vitamin D
· Fatty fish (tuna, salmon, sardines, mackerel, herring)
· Egg yolks
· Dairy products and dairy alternatives
Yao S, Kwan ML, Ergas IJ, Roh, J, Cheng TYD, Hong CC, McCan S, Tang L, Davis W, Liu S, Quesenbery C, Ambrosone CB, Kushi L. association of serum level of vitamin d at diagnosis with breast cancer survival. JAMA Oncol. 2016. 4188