A recent Danish study shows that women older than 50 who have worked outside for many years have a lower risk of breast cancer. Vitamin D may be the reason why. Scientists believe vitamin D may play a crucial role in moderating breast cell growth, specifically stopping the growth of cancer cells.
Learn more about how vitamin D benefits breast health and how to get it.
Vitamin D and breast cancer: What’s the connection?
According to one study, women who have the lowest levels of vitamin D have a 45% increased risk of breast cancer, compared to women with the highest levels of vitamin D in their blood.
The Danish study, published in the journal Occupational and Environmental Medicine, examined a subset of women who worked outdoors and compared them to women who worked indoors. It found that the women who had 20 or more years of exposure to sunlight through work had lower odds of a breast cancer diagnosis.
What is vitamin D and where can you get it?
Vitamin D helps the body function properly. You can get vitamin D through diet, but a primary source is sunlight. An inactive form of vitamin D in the skin gets activated by spending time in the sun and being exposed to ultraviolet radiation. As more women avoid direct sunlight or use sunscreen, the production of vitamin D occurs less frequently.
No research has identified how much vitamin D women need to reduce their risk of breast cancer. But there has been research that correlates higher vitamin D levels at the time of diagnosis with better breast cancer survival rates.
Cancer benefits aside, vitamin D also helps promote bone growth, so it’s important to take in the recommended daily allowance:
- Women age 14 to 70: 600 international units (IU) daily
- Women 71 and older: 800 IU daily
Tips for getting more vitamin D
You can get the highest levels of vitamin D at midday. Thirty minutes of full-body sun exposure causes the skin to make 10,000-20,000 international units of the vitamin. Spending just 15 to 20 minutes three days a week in the sun is likely sufficient.
It’s important to weigh the pros and cons of sun exposure considering its link to skin cancer, though. Talk with your doctor about what’s safe and consider factors such as geographic location and skin color.
You can also obtain vitamin D from sources such as:
- Eggs, especially the yolk
- Seafood such as salmon, oysters and sardines
- Supplements including cod liver oil and multivitamins
- Vitamin D-fortified foods including milk, yogurt, orange juice, soy milk and cereals
- Wild mushrooms
Signs of vitamin D deficiency
You may be unaware of a vitamin D deficiency because the symptoms can be very general, such as:
- Bone pain
- Fatigue
- Mood changes, such as depression
- Muscle weakness or pain
To diagnose vitamin D deficiency, your provider will order a test that measures levels of vitamin D in the blood. Treatment generally involves vitamin D supplements.
If you are concerned you might not be getting enough vitamin D or about your risk for breast cancer, contact your primary care provider.
