If you are over 60, you have an increased risk of developing a vitamin D insufficiency, according to the Office of Dietary Supplements. This is partly because your skin is unable to synthesize vitamin D as efficiently as it used to. Spending more time indoors or having a poor or restricted diet may also cause a vitamin D insufficiency. Taking a vitamin D supplement can help ensure that you get enough of this important vitamin.
Recommended Dietary Allowance
The Institute of Medicine establishes recommended dietary allowances for each vitamin and mineral, based on age and gender. The RDA for vitamin D for those ages 51 to 70 is 15 mcg a day, while the RDA for those older than 70 is 20 mcg a day. This is the equivalent of 600 IU for those between the ages of 51 and 70 and 800 IUs for those older than 70.
Tolerable Upper-Intake Levels
Although getting slightly more than the RDA is usually safe, getting significantly more may increase your chances of an adverse reaction. Because of this, the Institute of Medicine establishes tolerable upper-intake levels for each vitamin and mineral. This is the maximum amount of a vitamin or mineral you can safely consume without increasing your chances of side effects. The upper-intake level for vitamin D is 100 mcg a day for anyone older than 9. This is the equivalent of 4,000 IU a day.
Getting too much vitamin D may cause a loss of appetite and weight, increased urination or heart arrhythmia. It may also raise calcium levels in the bloodstream, which could damage your heart, kidneys and blood vessels, according to the Office of Dietary Supplements. Older adults need to monitor their vitamin D intake via fortified foods and supplements to avoid exceeding this amount.
Although most adults over 60 should follow the RDA and tolerable upper-intake levels when deciding how much vitamin D to take, there are some exceptions. Those who have been diagnosed with a vitamin D deficiency may need larger amounts of the vitamin until the deficiency is corrected. Adults with limited sun exposure or darker skin and those who are obese or have undergone gastric-bypass surgery may also need more vitamin D. Some people with malabsorption issues may additional supplementation, as well. If you think any of these circumstances apply to you, talk to a doctor about how much vitamin D you should be getting.
Vitamin D can react negatively with some prescription medications, including steroids, orlistat, cholestyramine, phenobarbital and phenytoin. It also may interact negatively with other medications or supplements. Because of this, talk with your doctor or pharmacist about all of your current medications and supplements before beginning vitamin D supplementation. If you experience any adverse side effects after taking vitamin D supplements, call your doctor for advice.