Pregnant Women Need More Vitamin D

Healthnotes Newswire (April 19, 2007)—Many pregnant women don’t get enough vitamin D, which could put their babies at risk for rickets and other health problems, according to a study in the Journal of Nutrition.

Rickets, a softening and weakening of the bones from too little vitamin D, was thought to be a thing of the past, but in recent years it’s been making a comeback. By aiding in calcium absorption, vitamin D helps the skeleton form properly and helps maintain healthy bones throughout life.

Besides its role in skeletal development, vitamin D is also involved in immune function, neurological health, and placental development. Children who don’t get enough vitamin D early in life are at higher risk for type 1 diabetes, asthma, autoimmune diseases, and schizophrenia.

Sunlight is a major source of vitamin D. Through a series of chemical reactions, ultraviolet light from the sun converts cholesterol into vitamin D. People with more of the pigment melanin in their skin (darker skinned individuals) don’t produce as much vitamin D from sunlight as lighter skinned people do. Also, living at higher latitudes limits sunlight-derived vitamin D for many months of the year. Liberal use of sunscreen greatly inhibits vitamin D production in the body.

“Pregnant women need about 1,000 IU of vitamin D per day,” says Lisa Bodnar, PhD, assistant professor of Obstetrics and Gynecology at the University of Pittsburgh School of Medicine, and the study’s lead author. “A typical prenatal vitamin contains only 400 IU.”

The new study looked at 400 pregnant women and their newborn babies living in the Pittsburgh, Pennsylvania, area to see if there were any seasonal or racial variations in their vitamin D status.

Although over 90% of the women used prenatal vitamins, many of them were not getting enough vitamin D. About 10% of white babies and almost 46% of black babies were vitamin D deficient, meaning that they were at risk for developing rickets.

“In our study, 400 IU of vitamin D was not enough to prevent deficiency. Studies are currently underway to determine if 1,000 IU, 2,000 IU, or 4,000 IU is safe and effective during pregnancy; but for now women should focus on taking in 1,000 IU per day. This can’t be met with a usual diet. Supplementation and/or moderate increases in summer/fall sunlight exposure are needed,” Dr. Bodnar said.

Infants who are exclusively breast-fed are at particularly high risk for vitamin D deficiency and should be given vitamin D supplements. Speak with your pediatrician to determine what amount is right for your baby.

“Black and white pregnant women residing in northern United States and their [babies] are at high risk of vitamin D insufficiency, even when they regularly use a prenatal vitamin,” the authors concluded.

Besides sunlight, vitamin D can be obtained from cod liver oil, salmon, tuna, mackerel, egg yolks, and fortified foods.

(J Nutr 2007;137:447–52)

Kimberly Beauchamp, ND, earned her bachelor’s degree from the University of Rhode Island and her Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. She cofounded South County Naturopaths in Wakefield, RI. Dr. Beauchamp practices as a birth doula and lectures on topics including whole-foods nutrition, detoxification, and women’s health.

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