Vitamin D helps our bodies absorb calcium, which is necessary for good bone health. Vitamin D also helps our immune, muscle, and nervous systems work properly. Plus, vitamin D may have an important role in maintaining normal breast cell growth, given emerging research results suggesting an association between a higher risk of breast cancer and low levels of vitamin D.
Vitamin D has been in the news lately because most doctors and dietitians agree that the current recommended intake levels are too low. Current recommended levels are:
- 600 IU (international units) for people age 1 to 70
- 800 IU for people age 71 and older
- 600 IU for pregnant and breastfeeding women
But how much vitamin D is enough isn’t clear yet.
Most of the vitamin D in our bodies is made when skin is exposed to sunlight. An inactive form of vitamin D in the skin is activated by sunshine. But as more of us spend our time inside, out of the sun, or wear sunscreen when we do go out, the amount of vitamin D we get from the sun is decreasing. We get smaller amounts of vitamin D from fortified milk and other foods, fatty fish, and eggs.
Take it outside: The easiest way to up your vitamin D level is to get more direct sunlight exposure. Just 15 minutes in the sun, 3 times a week can give you more than the current recommended amount of vitamin D. And while it’s impossible to overdose on vitamin D from the sun, sun exposure does have risks. Too much sun exposure increases your risk of skin cancer, including melanoma, the most dangerous type.
Most experts recommend you continue using protection when ultraviolet (UV) radiation levels are moderate or high. UV rays are invisible, so you can’t tell if you’re exposed or not. The U.S. Environmental Protection Agency and the National Weather Service developed the UV Index, which indicates the strength of UV rays on a scale from 1 to 11+ based on your zip code. Check that before you go outside.
Still, the darker your skin and the farther away from the equator you live, the less vitamin D you’ll produce. So many people may have a hard time getting enough vitamin D from only sun exposure.
Is a supplement right for you? Before you take any vitamin D supplements, it’s important to know what you vitamin D serum level is. You can find out with a simple blood test that your doctor can order for you when you’re in for a routine physical. Vitamin D researchers recommend a serum level of 40-60 ng/ml (nanograms/milliliter). It’s also important to talk to your doctor about what a good vitamin D serum level is for you and the risks and benefits of any supplement. My own level was low, just 16. To get back into the normal range, first my doctor prescribed high-dose vitamin D (requires a prescription) over 6 weeks, then a daily maintenance dose to stay in the normal range. About 6 months later, my level was re-checked to make sure I was taking the right dose. For me, 2,000 IU of vitamin D3 is the correct daily dose (and I prefer the gelcaps to the tablets). Some doctors may recommend less, between 400-2,000 IU. Less often doctors might recommend more than 2,000 IU/day. Taking too much vitamin D occasionally can cause you to have too much calcium in your blood. If you’re going to take a vitamin D supplement, most experts recommend taking the D3 form of the vitamin, not the D2 form.
Dietary solutions: Many fish, including:
- salmon
- herring
- catfish
- oysters
- mackerel
- sardines
- steelhead trout
are rich in vitamin D. Make sure you choose your fish carefully to avoid any species that may have high levels of mercury. For more information, visit the Exposure to Chemicals in Food page in our Lower Your Risk section.
Taking 1 to 3 teaspoons of cod liver oil per day as a supplement can also help meet your vitamin D requirements. (Be sure to buy mercury-free fish oil supplements.) Still, if you’re like me, you probably think cod live oil looks, smells and tastes DISGUSTING. So try these other fortified foods, though they have lower levels of vitamin D:
- milk
- some yogurt (read the label to see if it says “fortified with vitamin D”)
- some orange juice (read the label to see if it says “fortified with vitamin D”)
- some soy milk (read the label to see if it says “fortified with vitamin D”)
When I was first diagnosed my (initial) oncologist tested my vitamin D and calcium levels. I have always paid attention to my nutrition and vitamins, but since I live in Alaska I knew I was at risk for low vitamin D. When my oncologist told me that my calcium level was fine but (as I had expected) my D was low, imagine my surprise when he told me to take more calcium to help raise my vitamin D levels!!!!! I questioned the suggestion, and voiced my concern about hypercalcemia, but they repeated their same recommendation: take more calcium. I knew that taking more D can help you absorb more calcium, but I was sure the opposite was not true. I double-checked with a dr. of nutrition who confirmed I was right. I then changed oncologists. Wow, it’s amazing how little some drs. know about nutrition.
Dr. Weiss, what do we do about milk——–Google Milk and risks and read articles by Ganmaa Need advice?
Hi sas-schatzi,
Thank you for participating in this discussion. We understand that there are various schools of thought about the impact of dairy on breast cancer risk. Based on the data available at this time, there is no clear, proven connection between dairy and breast cancer risk. We do suggest people use organic, fat-free, antibiotic-free dairy products with no added hormones to avoid exposure to pesticides and synthetic hormones. This is something we will continue to follow and update here and in the Lower Your Risk section.
For anyone interested in milk alternatives for your cereal and coffee, Dr. Weiss does have a column on soy, almond, and other dairy alternatives coming soon.
Thank you!
Caroline
Assistant Editor