Health Articles

Lack of vitamin D made worse in winter: 'We can't rely just on sunlight'

The Daily News (Nanaimo)
Thu 06 Nov 2003
Byline: Lauren Neergaard
Source: Associated Press

WASHINGTON -- Millions of North Americans may not get enough vitamin D, a nutrient important for strong bones. It is a problem made worse in the winter, when the sun's rays are not intense enough in most of the continent to help bodies make the sunshine vitamin.

Substituting food can be difficult because of a lack of vitamin D-rich options.

Doctors are already urging that breast-fed babies get vitamin D supplements to fend off a shocking return of rickets, a soft-bone disease, most often seen in children, that was thought eliminated decades ago.

With increasing evidence that adults too may lack the nutrient, scientists are debating whether it is time to pump up everybody's level of vitamin D.

Vitamin D helps bones absorb calcium, and rickets marks just the worst deficiency, specialists told a recent National Institutes of Health meeting to assess the issue.

In adults, bone-weakening osteoporosis "cannot be prevented at currently recommended doses," said Dr. Robert Heaney of Creighton University, a specialist on bone health.

Government blood tests suggest a surprising number of people do not get recommended amounts, especially those with dark-pigmented skin that does not produce as much of the vitamin from sunlight.

Half of black women of childbearing age lack enough vitamin D in their blood during the winter and 30 per cent in the summer, according to studies from the Centers for Disease Control and Prevention. That compares with 11 per cent of white women in the winter and two per cent in the summer. Levels among Hispanics fall in between.

A Canadian study, published in June 2002, found that when using conservative measures of what is adequate, about a third of people studied did not have sufficient vitamin D levels during at least one season a year.

When the measure was raised to what many experts consider is more indicative of an adult's vitamin D needs, 97 per cent of participants were deficient during at least one season of the year.

The authors of that study recommended adding vitamin D supplements to foods or urging people to take vitamin D pills.

In the U.S., the National Institutes of Health are now facing two questions: What to do about people who do not meet today's allotment and whether it is time to raise everybody's recommended dose.

Both will require much more research, says Mary Frances Picciano of the NIH's Office of Dietary Supplements.

In England, researchers writing last week in the journal Lancet urged that children below the age of puberty and pregnant women receive vitamin D supplements as a '"safety net."

While NIH considers what to recommend, people should make a special effort to eat foods fortified with vitamin D, advises CDC epidemiologist Kelley Scanlon.

"We can't rely only on sunlight exposure."

The best natural sources are fatty fish such as *salmon* -- a serving provides 90 per cent of today's recommended allotment. Smaller amounts are in organ meats, egg yolks and mushrooms.