Vitamin D plays an important role in protecting your bones, both by helping your body absorb calcium and by supporting muscles needed to avoid falls. Children need vitamin D to build strong bones, and adults need it to keep their bones strong and healthy. If you don’t get enough vitamin D, and you’re more likely to break bones as you age.
How Much Vitamin D Do You Need?
Women and Men
Under age 50 400-800 international units (IU) daily**
Age 50 and older 800-1,000 IU daily**
**Some people need more vitamin D. According to the Institute of Medicine (IOM), the safe upper limit of vitamin D is 4,000 IU per day for most adults.
Sources of Vitamin D
There are three ways to get vitamin D:
• Sunlight
• Food
• Supplements
Sunlight
Your skin makes vitamin D in reaction to sunlight and stores it in fat for later use. How much vitamin D your skin can produce depends on time of day, season, latitude, skin pigmentation, age, and other factors.
There are many reasons people do not have enough vitamin D. As we age, our skin loses its ability to generate vitamin D. People who live in cities or in institutional settings like nursing homes spend too little time outdoors. Even people who spend time outdoors often use sunscreen to prevent skin cancer. Sunscreen with an SPF as low as 8 reduces vitamin D production by 95 percent.
Vitamin D in Food
Vitamin D is found in very few foods. Sources include fatty fish like wild-caught mackerel, salmon, and tuna. Vitamin D is added to milk and other dairy products, orange juice, soymilk, and fortified cereals.
Check the food label to see if vitamin D has been added to a particular product. One eight-ounce serving of milk usually has 25% of the daily value (DV) of vitamin D. The DV is based on a total daily intake of 400 IU of vitamin D. So, a serving of milk with 25% of the DV of vitamin D contains 100 IU.
It is very difficult to get all the vitamin D you need from food alone. Most people must take vitamin D supplements to get enough to support bone health.
Vitamin D Supplements
If you aren’t getting enough vitamin D from sunlight and food, consider taking a supplement. Before adding a vitamin D supplement, check to see if any of the other supplements, multivitamins, or medications you take contain vitamin D. Many calcium supplements also contain vitamin D.
There are two types of vitamin D supplements. They are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Both types are good for bone health.
Vitamin D supplements can be taken with or without food and the full amount can be taken at one time. While your body needs vitamin D to absorb calcium, you do not need to take vitamin D at the same time as a calcium supplement. If you need help choosing a vitamin D supplement, ask your healthcare provider or pharmacist to recommend one.
How Much Vitamin D Should You Supplement?
To figure out how much vitamin D you need from a supplement, subtract the total amount of vitamin D you get each day from the recommended total daily amount for your age. For example, a 55-year-old woman who gets 400 IU of vitamin D from her calcium supplement should take between 400 and 600 additional IU of vitamin D to meet the 800 – 1,000 IU recommended for her age.
Vitamin D Deficiency: Are You at Risk?
Vitamin D deficiency occurs when you are not getting the recommended level of vitamin D over time. Certain people are at higher risk for vitamin D deficiency, including:
• People who spend little time in the sun or those who regularly cover up when outdoors;
• People living in nursing homes or other institutions or who are homebound;
• People with certain medical conditions such as Celiac disease and inflammatory bowel disease;
• People taking medicines that affect vitamin D levels such as certain anti-seizure medicines;
• People with very dark skin;
• Obese or very overweight people; and
• Older adults with certain risk factors.
Talk to your healthcare provider if you have any of these risk factors. If you have osteoporosis and also have a vitamin D deficiency, your healthcare provider may temporarily prescribe a high dose of vitamin D to bring you up to a healthy level.
A Guide to Calcium-Rich Foods
We all know that milk is a great source of calcium, but you may be surprised by all the different foods you can work into your diet to reach your daily recommended amount of calcium. Use the guide below to get ideas of additional calcium-rich foods to add to your weekly shopping list.