The Hottest Vitamin Under the Sun ( Part 3 )

New products fortified with vitamin D may help the many who are deficient. Recent studies have shown pregnant women who lived at a latitude of 54 to 55 degrees north (about as north as Central Canada) had insufficient levels, even among those who use supplements.² Mothers-to-be who have lower levels of vitamin D are more likely to give birth via cesarean section.³ And Turkish researchers encouraged pregnant women to supplement their diets with vitamin D in order to reduce the risk of their children contracting acute lower respiratory infections.⁴

Once the children are out of the womb, they may still not be getting all of their vitamin D needs. In the United States, 61 percent of children aged 1 to 21 years who completed the National Health and Nutrition Examination Survey 2001-2004 had insufficient levels of vitamin D.⁵ Only 4 percent had taken a 400 IU/d supplement of vitamin D for the past 30 days. That same study found deficiency was associated with elevated parathyroid hormone levels, higher systolic blood pressure, lower serum calcium and high-density lipoprotein (HDL) cholesterol levels.

The heart-health benefits of vitamin D don’t stop with the youth. A University of Colorado study found an inverse relationship between vitamin D levels and cardiovascular disease (CVD), as well as all-cause mortality.⁶ A review in The American Journal of the Medical Sciences states cross-sectional studies found vitamin D deficiency was associated with increased risk of CVD, including hypertension, heart failure and ischemic heart disease.⁷ And Reuters reported at a September 2009 meeting of the American Heart Association in Chicago, researchers presented study that found younger white women with vitamin D deficiencies are about three times more likely to have high blood pressure in middle age than those with normal vitamin levels.

Because vitamin D is necessary for calcium absorption into the body, vitamin D is closely associated with bone health. In fact, one Swiss study found among men and women, vitamin D status seems to be the dominant predictor of bone mineral density (BMD) relative to calcium intake.⁸ In the study, only women with vitamin D concentrations less than 50 nm seem to benefit from a higher calcium intake alone. In a later review of eight randomized controlled trials, those same researchers found supplemental vitamin D in a dose of 700 to 1,000 IU/d reduced the risk of falling among older adults by 19 percent.⁹ However, doses of supplemental vitamin D of less than 700 IU or serum 25-hydroxyvitamin D concentrations of less than 60 nmol/l did not reduce the risk of falling.

McBurney added supplementing with vitamin D is good for bone health throughout life. “Bones are remodeled every day, all our life,” he said. “So it is important to build bones when one is young, and to maintain adequate vitamin D status to maintain strong bones for life.”

The benefits of vitamin D go well beyond the heart and bones. Keeping vitamin D levels high may also protect against colon cancer,¹⁰ cold and flu,¹¹ Alzheimer’s disease,¹² multiple sclerosis,¹³ ovarian cancer¹⁴ and weight gain.¹⁵

With all the new studies finding vitamin D’s health benefits (every study referenced in this article is from 2009), the sunshine vitamin’s future is, well, sunny. “Scientists are discovering new insights into the role of vitamin D,” McBurney said. “With the unraveling of the human genome, we are living in a period of discovery unprecedented in history. The future is very exciting.”



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