Researchers at the University of California San Diego in collaboration with Creighton University, Medical University of South Carolina, and Grassroots Health Research have found an interesting relationship between Vitamin D and the development of Breast cancer.
Dr. Scott Christensen, professor of hematology and oncology at the University of California Davis and medical director at the U.C. Davis Cancer Care Network, told Healthline he was cautiously optimistic about the study.
What the research revealed
The findings are based on a meta-analysis of previously conducted clinical trials. One of the studies involved more than 3,300 participants and the other had more than 1,700 participants. The studies were conducted between 2002 and 2017.
All participants were women over the age of 55 and cancer-free at the time of enrolment. During the trials, they were given both vitamin D and calcium supplements and were followed for a mean period of four years.
The crux of the study is the concentration of vitamin D found within the blood. Researchers referred to it as serum 25-hydroxyvitamin D, or 25(OH)D, which is the main marker of vitamin D in the blood.
The authors concluded that women with a higher concentration of vitamin D in their blood had a lower risk for breast cancer compared with women who didn’t have these higher levels.
“Participants with blood levels of 25 (OH)D that were above 60 ng/ml had one-fifth the risk… compared to those with less than 20 ng/ml,” Cedric Garland, principal investigator, and co-author said in a press release.
What vitamin D does
Vitamin D is vital to your overall health.
It helps muscles move, lets nerves carry signals, and helps your immune system ward off disease.
“We know vitamin D keeps bones strong and it has an important role in normal cell growth,” Dr. Marissa Weiss, chief medical officer and founder of Breastcancer.org, told Healthline.
Weiss also practices at Lankenau Medical Center in Pennsylvania and serves as the director of breast radiation oncology and breast health outreach.
The current daily allowance of vitamin D for people ages 1 to 70 is 600 International Units (IU). This includes pregnant women. From birth to 12 months, it’s 400 IU. Adults over the age of 70 should have 800 IU.
There are two main ways for people to get enough vitamin D — through food and from the sun.
Oily fish such as salmon, sardines, and oysters are good sources of vitamin D. Supplements are another way to boost your intake.
Vitamin D is also produced in the body and stored in its inactive form, predominately in the skin. When people expose their skin to the sun, the rays transform the vitamin to its active form.
A lack of vitamin D
Both Weiss and Christensen say that concern over skin cancer due to sun exposure has resulted in a vitamin D deficiency in many populations.
Studies have shown an association between the decline in vitamin D consumption and the rise in breast cancer rates, but no study has made the direct link, according to Weiss.
“Breast cancer is on the rise so is one reason [a lack of] vitamin D?” she said. “It’s possible.”
The tricky thing about vitamin D deficiency is that there aren’t any symptoms, Weiss added. The deficiency is invisible so the only way to find out is through a blood test that checks vitamin D levels.
She noted that women, in particular, should get their levels detected so they can figure out if they need to take in more vitamin D either through food or a supplement.
“People need to know and they should talk their doctor about it,” Weiss said.
The only part of the equation
Christensen cautioned though that vitamin D isn’t the only factor that can influence the development of breast cancer.
Like all cancers, breast cancer is caused by a multitude of issues. Diet, exercise, lifestyle choice, and genetics all play a role. Vitamin D is just one part of that equation.
But, the study out of U.C. San Diego certainly advances the line of inquiry regarding vitamin D and breast cancer, he added.
The next steps would be more in-depth trials, such as ones that take age or high-risk populations into consideration when assessing vitamin D and association with breast cancer.
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