Vitamin D, Calcium, and Bone Health in Seniors
4 of 12 in Series: The Essentials of Vitamin D Benefits
When seniors comply with their recommended calcium intake and their vitamin D levels are sufficient, bone fracture risk is significantly reduced compared to seniors who don’t get enough calcium or have vitamin D deficiency. Even when vitamin D is sufficient, it’s essential that seniors get enough calcium in their diet.
In November 2010, an expert committee gathered together by the Institute of Medicine of the U.S. National Academy of Science released its new recommendations for vitamin D intake. Their recommendations for older people are similar to ones released in April 2010 by the International Osteoporosis Foundation (IOF).
Both of these recommendations are based on a type of research called randomized clinical trials. In these studies scientists follow two similar groups — one that gets a treatment (like vitamin D) and one that gets a placebo or a pill that’s not supposed to do anything.
Neither the people in the study nor the scientists know who is getting what treatment until the end of the study (that’s called a double blind study). For the scientists to say that a treatment works, it has to help the people on the treatment significantly more than any effect seen in the placebo group.
The IOF and the Institute of Medicine committee agreed on several points:
Vitamin D acts on muscle tissue and improves grip strength and muscle mass.
Supplementing with vitamin D may improve lower extremity performance and reduce the risk of falling.
Supplementing with a dose of at least 600 IU daily was needed to see a detectable effect on falls.
Vitamin D affects fracture risk through its effect on bone metabolism and risk of falling.
Vitamin D reduces rates of bone loss in older women.
Supplementing with a dose of at least 600 IU daily was needed to see an effect on nonvertebral and hip fractures.
Making the case for more vitamin D
Based on the results of the randomized clinical trials, both the IOF and the Institute of Medicine committee recommended that people take more vitamin D. Their findings include the following:
The IOF argued that women need 800 to 1,000 IU of vitamin D daily whereas the Institute of Medicine committee thought that 700 to 800 IU was enough.
The two groups pointed out that the amount of dietary vitamin D a person needs varies depending on the starting level of 25-hydroxyvitamin D, how much body fat a person has, the amount of sun exposure, and other factors.
The IOF recommended that physicians may need to adjust vitamin D intake upward in some special groups (to as high as 2,000 IU each day). But someone who has fat malabsorption may need even larger doses of vitamin D to achieve target 25-hydroxyvitamin D levels.
The IOF also noted that because uncertainty exists about whether vitamin D3 is more effective than vitamin D2 at raising the 25(OH) vitamin D, physicians should use vitamin D3 when available.
There was a big disagreement between the two groups on the level of serum 25-hydroxyvitamin D that people should reach to help their bones and prevent osteoporotic fractures.
The IOF felt that 30 ng/ml [75 nmol/L] is the appropriate target level for serum 25-hydroxyvitamin D, but the Institute of Medicine committee showed that this estimate was based on a flawed study. As a result, the Institute of Medicine committee recommended 20 ng/ml [50 nmol/L] as the target level.
The Institute of Medicine committee set their requirement with the assumption that someone gets no vitamin D from sunlight. It’s also critical to realize that these requirements are set for normal, healthy people not people with specific diseases. However, the Institute of Medicine report did make a point to explain that the vitamin D dose may need to be adjusted upward when people have trouble absorbing fat or for people who are obese.
Factoring in calcium in older women's diets
Calcium isn’t as well absorbed from the intestine in older women compared to young women. Also, the daily intake of calcium by every age group of American women is less than the daily recommended intakes, sometimes by as much as 500 mg a day. This means older women are doubly cursed — they don’t get enough calcium in their diet, and they don’t absorb the calcium they do get very well.
Many elderly women don’t like dairy products because they develop lactose intolerance and dairy upsets their stomach. For that reason, doctors recommend that most women take a daily supplement of 1,000 mg to reach their recommended levels.
Make sure you’re getting 1,000 mg of elemental calcium. For example, a 1,250 mg calcium carbonate tablet contains only 500 mg of elemental calcium, so you need to take two daily. You should take these tablets at different times of day to make sure you get the most calcium from the supplement.
If you have trouble swallowing the large calcium tablet, you can get it in a chewable form or as a liquid calcium supplement.
Based on recent evidence, there may be an increased risk of calcification in arteries and mortality with calcium intakes greater than 1,500 mg per day. The total intake from supplements and diet should not exceed this amount.