Vitamin D: The
Meagan Brown , PharmD Candidate 2009
Albany College of Pharmacy
Prepared during Consumer Health Information Corporation Clerkship
Isn’t it great to finally see the sun? Did you know that your body can make its own
Vitamin D when you’re out in the sun?
This time of year the sun is out longer and getting stronger during the middle of the day. But unprotected sun exposure can damage the skin. Repeated exposure could lead to skin cancer. Regular use of sunscreen protects the skin but also decreases absorption of the ultraviolet B (UVB) sunlight that is needed to produce vitamin D by the skin. This can lead to a person having low vitamin D levels.
Why Do We Need Vitamin D?
Vitamin D helps calcium keep your bones healthy. Over time, if your body does not have enough vitamin D and calcium your bones can become brittle, lose strength, and osteoporosis could develop. Having enough vitamin D and calcium allows the muscles to work best. Falls in elderly people can occur more if these levels are low. If vitamin D levels are too low, you could have a higher risk of developing colon cancer, stroke, heart attack, high blood pressure and diabetes.
How Much Sun Do You Need to Make Vitamin D?
The length of time varies for each person. A fair-skinned person’s body could make about 3000 International Units (IU) in 5-15 minutes during the spring and summer. The legs and arms would need to be exposed to the midday sun without sunscreen or clothing on them. The good news is that your body will never allow you to make too much vitamin D from sunlight.
Some people may not be able to get enough vitamin D from the sun due to any of the following reasons:
- If you regularly use an SPF15 sunscreen properly, it can decrease vitamin D formation by the skin by more than 98%.
- The skin of people over age 65 have less of the component that is needed to convert sunlight into vitamin D.
- The body fat of obese people may absorb the vitamin D made by the skin. Twice as much sunlight may be needed to get enough vitamin D in the blood.
- Dark skin blocks UVB light from being absorbed so 5-10 times more sun exposure is required than for fair-skinned people.
- The lack of UVB sunlight north of Atlanta in the winter allows for very little vitamin D to be made by the skin.
- People who need to cover up because they take medicines such as diuretics or certain antibiotics that may cause them to have skin reactions to sunlight.
Other Sources of Vitamin D
If your body is unable to make enough vitamin D on its own, using these sources may be necessary.
Foods naturally having it:
- Salmon (fresh, wild): 600-1000IU in 3.5 ounces
- Cod liver oil: 400-1000IU in 1 teaspoonful
Foods that are fortified:
- Milk and yogurt: 100IU in each 8 ounce cup
- Breakfast cereals: about 100IU in each serving
Over-the-counter supplements: available in the vitamin section of the pharmacy
- Multivitamins: contain 400IU of Vitamin D
- Vitamin D capsules: 400, 800, 1000, 2000 IU
How Much Do You Need?
- Children and adults under 50: 200IU each day
- Adults between 50 and 70 years old: 400IU each day
- Adults over 70: 600IU each day.
There are some people who may need more. Check with your doctor or pharmacist to determine the appropriate dose for you. Also, check if you should be taking calcium with vitamin D.
Are there side effects?
Not usually, but taking large doses (greater than 10,000IU) daily over time can lead to high levels of calcium in the body. This may cause ongoing nausea and vomiting, metallic taste, muscle weakness, calcium stones in the kidneys, mental status changes and changes in heart beat. If you experience any of these side effects, contact your doctor.
Your body can make just the right amount of vitamin D if you expose part of your skin to the sun for a few minutes each day. Check with your doctor to see if you can safely take a few minutes to get your vitamin D from the sun. If this is not possible for you, you will have to get it from food or supplements. If you have any questions about using vitamin D, contact your doctor or pharmacist.
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