More Vitamin D in Pregnancy May Lead to Healthier Babies
Vitamin D has been the topic of much research in recent years. Researchers are studying its role in preventing a number of diseases, including certain autoimmune diseases (type 1 diabetes, multiple sclerosis, and rheumatoid arthritis), osteoarthritis, cancers (especially colon cancer), gum disease, and high blood pressure.
Vitamin D is also an essential nutrient in pregnancy. Not only essential for bone health, high vitamin D levels in moms-to-be are also associated with better grip strength and more muscle mass in infants.
In a recent study published in the Journal of Clinical Endocrinology and Metabolism, researchers from the University of Southampton studied more than 600 mother-child pairs in the UK. The team investigated the associations between maternal vitamin D intake during 34 weeks of gestation and the resultant effects in their children up through age four.
Grip strength dynamometers, which measures force, were used to assess hand function in the children. A high concentration of vitamin D during the prenatal period was positively associated with grip strength and muscle mass. And the higher the vitamin D levels were, the higher the ratings for strength and muscle mass.
What exactly does this mean? While not yet widely used in the medical community, grip strength can be an important screening tool in assessing a person’s overall health, says Richard Bohannon, a professor of physical therapy at the Neag School of Education, not involved with the study.
“Weakness is one of those cluster signs of frailty,” says Bohannon. “There are other things, like unintentional weight loss and a particularly slow gait. But grip strength gives you an overall sense of someone’s vitality. It is reflective of muscle mass and can be used to predict things in the future like post-operative complications and even death.”
The researchers believe that children with greater muscle strength will eventually become adults with greater strength and ultimately be less likely to become frail even into senior adult age.
"These associations between maternal vitamin D and offspring muscle strength may well have consequences for later health; muscle strength peaks in young adulthood before declining in older age, and low grip strength in adulthood has been associated with poor health outcomes including diabetes, falls and fractures," said Dr. Nicholas Harvey, senior lecturer at the University of Southampton.
During pregnancy, the body needs vitamin D to maintain proper levels of calcium and phosphorus which help build baby’s bones and teeth. Having a deficiency during pregnancy can cause low birth weight, growth retardation, skeletal deformities, and delayed physical development. Vitamin D deficiency is also associated with a greater risk of pregnancy complications, including preeclampsia and a greater likelihood of c-section.
Sufficient levels of vitamin D, especially while pregnant, may also play an important role in regulating the immune system and cells, where it may even help prevent cancer.
How much vitamin D you need
The National Academy of Sciences currently recommends that pregnant women get 200 IUs (5 micrograms) of vitamin D each day if they're not exposed to adequate sunlight (such as those living in northern areas). But some experts believe this amount isn't nearly enough, so the National Academy of Sciences is reviewing its guidelines on vitamin D.
"I recommend that pregnant women take a supplement of 4,000 IU of vitamin D a day. And I recommend that lactating women take a supplement of 6,000 IU daily," says Bruce Hollis, professor of pediatrics at the Medical University of South Carolina, who has researched vitamin D needs.
Food sources of vitamin D
Fish liver oil, fatty fish, and fortified milk, egg, and cereal products all contain vitamin D. Be sure to check food labels: Some eggs, cheeses, yogurts, and cereals are fortified while others aren't. All milk is vitamin D fortified.
Here are some of the best food sources of vitamin D:
3 ounces catfish, cooked: 570 IU
3.5 ounces salmon, cooked: 360 IU
3.5 ounces mackerel, cooked: 345 IU
3 ounces tuna fish, canned in oil: 200 IU
1.75 ounces sardines, canned in oil, drained: 250 IU
1 cup milk, fortified with 25% of daily value (DV) of vitamin D: 100 IU
1 cup orange juice, fortified with 25% of DV of vitamin D: 100 IU
1 cup fortified skim milk: 98 IU
1 tablespoon margarine, fortified: 60 IU
1 cup ready-to-eat cereal, fortified with 10% of DV of vitamin D: 40 IU
1 egg yolk: 20 IU
Nicholas C. Harvey, et al. Maternal Antenatal Vitamin D Status and Offspring Muscle Development: Findings From the Southampton Women's Survey. Journal of Clinical Endocrinology and Metabolism, January 2014
Bonny Specker. Vitamin D requirements during pregnancy. Am J Clin Nutr December 2004 vol. 80 no. 6 1740S-1747S
University of Connecticut - Grip Strength Is Good Indicator of Overall Health