Years ago doctors were mainly concerned about vitamin D deficiency in children. Foods were fortified with vitamin D to prevent the bone disease called rickets. Now we know that rickets was only the tip of the iceberg and that seniors are also at high risk for vitamin D deficiency. According to a recent study in the journal Age and Ageing, vitamin D deficiency may contribute to osteoporosis, muscle weakness, hip fractures, diabetes, cancer, heart disease, arthritis and poor general health in seniors.
Sources of Vitamin D
Vitamin D is not common in many foods, but it is very important for helping your body absorb the calcium you need to build bone strength. Vitamin D also helps you fight off many diseases and is important for proper nerve function. Sources of vitamin D include:
- Food. There are few foods that contain vitamin D naturally. The best foods for vitamin D are cod liver oil, salmon, mackerel, tuna, beef liver, cheese and egg yolks.
- Vitamin D fortified foods. Since it is difficult to get enough vitamin D naturally, many foods have vitamin D added to them. These foods supply most of the vitamin D in the American diet. Milk, breakfast cereals, and juice drinks are commonly fortified with vitamin D.
- Sunlight. For most people exposure to sunlight is the most important source of vitamin D. Sunlight converts cholesterol to vitamin D in the body.
- Vitamin D supplement. Between 2005 and 2006 the National Health and Nutrition Examination Survey found that only about one-third of Americans were getting enough vitamin D in their diet. A recent study published in the Archives of Internal Medicine suggests that older adults can reduce their risk of bone fractures by taking an oral supplement of vitamin D every day.
Why Are Seniors at Risk?
People over age 50 have an increased risk of vitamin D deficiency and the risk increases with age. As people age they lose some of their ability to synthesize vitamin D from sunlight. Vitamin D also needs to be activated in the kidney before it can be used by the body and this function also decreases with age. Finally, elderly people who are homebound are less likely to get outdoor exercise and activity. Researchers have suggested that it takes up to 30 minutes of sun exposure twice a week to make a sufficient amount of vitamin D from sunlight.
How Much Vitamin D Do You Need?
You need more vitamin D as you get older. According to the Food and Nutrition Board at the Institute of Medicine of The National Academies, an adequate intake of vitamin D up until age 50 is 200 International Units (IU) for both men and women. Between age 50 and 70 the adequate daily intake is 400 IU for men and women. After age 70 the adequate intake is 600 IU for men and women.
“The clinical manifestations of suboptimal vitamin D levels has a significant physical, psychological and financial impact on older people and society as a whole,” —Age and Ageing
Because seniors are at greater risk for vitamin D deficiency, there have been many recent studies to determine if vitamin D supplements are useful in preventing falls and fractures. Some studies have found that a supplement of 400 IU daily is adequate and effective for reducing falls and fractures in seniors. Other studies suggest that the best dose for fracture reduction is 800 IU daily, and still others have found that a dose of 800 to 1000 IU daily is best.
It is possible to take too much vitamin D supplement. Symptoms of vitamin D toxicity include nausea, vomiting and weakness. Too much vitamin D can cause your calcium level to increase and lead to mental confusion and heart arrhythmias. Too much sun exposure does not lead to too much vitamin D (though there are skin cancer risks to consider). To be in danger of overdosing on a vitamin D supplement you would need to take well over 2,000 IU daily.