Last week (in "Vitamin D: Is It a Miracle? [Part 1]"), we started to delve into the world of vitamin D. Many of you posted comments about your experiences with vitamin D and how much you’ve benefited from taking a vitamin D supplement.
Besides preventing rickets and osteomalacia, what can vitamin D really do for us? What’s the evidence supporting the claims that vitamin D can do more besides keep our bones healthy? Let’s take a look at what we know about this “sunshine vitamin.”
Osteoporosis is a disease of the bones. Bones become very weak and brittle and, if not treated, over time bones can break even with the mildest activity, such as bending over or coughing. Both men and women can be affected by osteoporosis (it’s not just a “woman’s disease”).
One key to preventing osteoporosis is building up enough bone mass in your younger years. Once you’re in your 30’s, you’ve pretty much reached your peak bone mass. After that, you start to lose some of your bone mass as time goes on. While calcium, of course, is vital for bone health, vitamin D plays a prominent role as well.
Vitamin D is needed to absorb calcium in the gut; without this vitamin, calcium can’t do its job of strengthening bones. In addition, vitamin D helps to regulate blood calcium levels and enhances calcium reabsorption from the kidneys. So, calcium and vitamin D work in tandem.
Vitamin D is so important for bone health that one of the drugs for treating osteoporosis, Fosamax (alendronate sodium), comes in a formulation called Fosamax Plus D. This medication contains 2,800 international units (IU) of vitamin D.
Muscle Weakness and Pain
If you’re deficient in vitamin D, you might experience muscle weakness and/or muscle pain. Since there are multiple reasons for muscle weakness, any muscle symptoms should be evaluated by a health-care provider. Muscle weakness in the elderly is cause for concern, as it puts the person at risk for falling (and that leads to a whole host of other problems).
A blood test can determine a person’s level of vitamin D, and low levels can easily be treated with vitamin D supplements. And adequate vitamin D intake can prevent problems from occurring in the first place. One study involving nursing home residents found that those taking 800 IU of vitamin D daily were 72% less likely to fall than those given a placebo.
Some research indicates that infants and children given vitamin D supplements are less likely to develop Type 1 diabetes. In one recent study published online in the Archives of Disease in Childhood, children who were given vitamin D were 30% less likely to develop Type 1 diabetes than those not taking a supplement.
It’s already well-known in diabetes circles that children living in areas of the world without much sunlight, such as Finland, have higher rates of Type 1 diabetes than those in in sunnier parts of the world. In fact, infants in Finland are 400 times more likely to develop diabetes than infants in Venezuela. Infants should receive 200 IU of vitamin D daily.
Vitamin D may also play a role in preventing Type 2 diabetes. One study, in the journal Diabetes Care, looked at data from 4,000 men and women. Vitamin D levels were significantly lower in the 187 people who developed Type 2 diabetes than in those who didn’t get diabetes. And those with the highest blood levels of vitamin D were 40% less likely to get diabetes.
Also, data from the Nurses’ Health Study found that women who took a combination of 1,200 mg of calcium and more than 800 IU of vitamin D daily had a 33% lower chance of getting Type 2 diabetes than women taking smaller amounts of these nutrients. The thinking is that both calcium and vitamin D play a role in glucose metabolism in the body.
Heart Attack and Stroke
Vitamin D really gets around—around the organ systems, that is. A study published in a January 2008 issue of Circulation, using data from the famous Framingham Heart Study, indicated that participants with the lowest blood levels of vitamin D were 62% more likely to have either a heart attack or a stroke than those with higher vitamin D levels. The results were so impressive that one of the study authors believes that people should take between 1,000 and 2,000 IU of vitamin D every day. (The jury is still out on the optimal dose of vitamin D.)
More on the wonders of vitamin D next week!