Pregnancy and Vitamin D Status
Read the following article that I picked up at my doctor's office the other day. It is a nice overall piece about vitamin D deficiency and its role in almost every aspect of this important nutrient.
More Know About Vitamin D Benefits
By Don Sapatkin
Amy McDonald, 34 weeks into her second pregnancy with gestational diabetes, was in for a routine checkup in Bala Cynwyd: blood pressure (fine), fetal heartbeat (loud), review of home blood-sugar monitoring (time-consuming).
A lab test for Vitamin D had come back low on a previous visit, and McDonald was now taking supplements.
"Any problems with the Vitamin D?" asked her doctor, Daphne M. Goldberg, who had recommended at least 10 times the dosage in federal guidelines. (No problems.)
Most women don't hear about Vitamin D during prenatal visits. Indeed, studies linking widespread deficiency of the "sunshine vitamin" to a host of seemingly unrelated conditions - among them heart disease, arthritis, depression, psoriasis, influenza, and several types of cancer - have been coming so fast and furious that government guidelines can't keep up. No one even knows what a "normal" level should be.
Many people aren't waiting. Sales of the supplement in the United States were an estimated $425 million in 2009, up 82 percent from the previous year and 10 times what was spent in 2001, according to the Nutrition Business Journal.
An authoritative federal review due next month is expected to raise recommended amounts. But scientists on the panel, whose guidelines will affect medical practices, fortified foods, and everyday consumer purchases, are likely to be cautious. Most major research findings on Vitamin D are recent, and the amount required to overdose has not been definitively shown.
Some prominent scientists argue that such thinking is backward. Vitamin D, which is naturally produced in the skin in reaction to sunlight, is far more benign than a pharmaceutical. And with Americans spending more time on computers indoors and less time without sunscreen outside, surveys show that at least half - and up to 90 percent - do not have enough.
"We have this vast experiment going on," said Carol L. Wagner, a neonatologist at the Medical University of South Carolina in Charleston. "We are looking at the rampant Vitamin D deficiency throughout the country."
Continuing the status quo, she said, will harm far more people than would higher doses of a vitamin that her research has shown to be safe.
Wagner cowrote American Academy of Pediatrics guidelines that 2 years ago doubled the recommended Vitamin D intake for children to 400 IU (international units) a day and said obstetricians should consider screening all pregnant women for deficiency.
Last spring, she and colleagues reported the findings of their latest study completed by 350 pregnant women who were randomly placed into three groups. One group received 400 IU of Vitamin D daily, the amount that is in most prenatal vitamins and multivitamins. The other groups got either 2,000 IU or 4,000 IU, which happens to be the amount that Goldberg gave her pregnant patient with gestational diabetes.
The risk of a group of problems such as preterm labor, preterm birth, and all kinds of infections was reduced by 50 percent for those who got the highest amount compared with the lowest. Not a single adverse event was attributed to Vitamin D, and babies born to women in the highest group had significantly better levels of the vitamin in their blood.
Yet the research, presented at a big pediatrics meeting in Vancouver, was not formally discussed at a major OB/GYN conference in San Francisco 2 weeks later, and most obstetricians probably are unaware of it.
Vitamin D has been through this before.
As the Industrial Revolution moved families from farms to factories, pioneering doctors noticed that the serious bone deformities of childhood rickets were epidemic in polluted European cities but not in rural areas.
They treated the disease with sunlight but were ignored by the medical community until X-rays proved the case in the 1920s. The U.S. government recommended limited sun for children, and dairies began fortifying products with Vitamin D.
Rickets disappeared. The workings of Vitamin D - activated in the kidneys and critical for metabolizing calcium to build and maintain bones - had been unraveled.
Or so it was thought.
Over the last few decades, scientists have discovered that Vitamin D - technically not a nutrient at all but a hormone - regulates about 2,000 genes in different ways.
It plays a role in cell growth and death, and so has been linked to numerous cancers. It affects blood vessels, connecting it to high blood pressure and heart attacks. Its involvement with inflammation and the immune system brings an association with allergies and asthma, infections such as influenza and tuberculosis, and autoimmune disorders such as multiple sclerosis and type 1 diabetes.
In his recent book, "The Vitamin D Solution," physician and researcher Michael F. Holick cites studies finding that the incidence of many of these conditions - hypertension, MS, nine kinds of cancer - is greater the farther you live from the equator.
Dark-skinned people, who migrated to Northern latitudes relatively recently in human history, require more exposure to direct sunlight to produce the same amount of Vitamin D as those with lighter skin. African Americans' average Vitamin D levels are the lowest of any racial group - possibly helping to explain, Holick says, why studies show blacks suffer disproportionately high rates of several diseases even if they have equal access to health care.
He also believes that rising rates of some diseases are tied to Americans' love affair with sunscreen.
Vitamin D advocates urge limited sun exposure. The dermatologists' message is to not go out unprotected.
It's not that dermatologists are against Vitamin D.
The link between too much sun and skin cancer is known but complex, said Christopher J. Miller, director of dermatologic surgery at the Hospital of the University of Pennsylvania. On the other hand, the link between too little sun and other cancers is intriguing but not proven.
Plus, "You can get Vitamin D in other ways," Miller said: from supplements and diet.
Getting it from diet means fortified foods, the main source for the vast majority of Americans. The amount of Vitamin D they contain has not changed since the 1930s. To ingest what advocates now consider to be enough - 1,000 to 4,000 IU - would mean drinking 10 to 40 cups of milk a day or eating between a half-pound and two pounds of salmon or mackerel, fatty fish that are among the few significant natural food sources.
Vitamin D supplements can easily provide enough, and holistic doctors have been recommending several times the current guidelines for years. But others worry about toxicity.
"We are very reluctant to give pregnant mothers any medications," including "super vitamins," said Owen Montgomery, chairman of obstetrics and gynecology at Drexel University College of Medicine.
He said the latest research, while striking, is not enough to "change anyone's practice. I think what it should do is generate more funding for larger studies."
Pretty much everyone agrees that there should be more research. They also agree that Vitamin D deficiency is getting worse, even though no one knows what's normal because sophisticated tests used to measure levels in the blood didn't exist before civilization blocked out the sun. And doctors of all stripes concur that current federal guidelines are hopelessly out of date.
"We've been off by a factor of 10," said Holick, the author and a professor at Boston University School of Medicine. Holick was a member of the panel that set current federal guidelines in 1997 and he gave expert testimony to the committee that is updating them now.
Distributed by McClatchy-Tribune Information Services.