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Eating foods fortified with vitamin D may help pregnant women with low levels of the vitamin. Getty Images
  • A new study finds low levels of vitamin D at birth may put children at increased risk of high blood pressure later on.
  • Pregnant women and expectant parents should consult with a dietitian or nutritionist if they are worried about their vitamin D levels.
  • Eating foods fortified in vitamin D or giving infants vitamin D supplementation in certain cases can also help their health.

In recent decades, a growing number of children have developed high blood pressure. And this can mean bad news for their future health.

Those who develop high blood pressure in childhood are more likely to have high blood pressure in adulthood. In turn, that puts them at higher risk of developing cardiovascular disease, such as heart attack and stroke, in later life.

So what puts kids at risk for hypertension at such a young age?

According to a new study published in the journal Hypertension, low levels of vitamin D may put children at heightened risk of elevated blood pressure.

After controlling for multiple risk factors, the authors of the study found that children who had low levels of vitamin D at birth or in early childhood were more likely than kids with higher levels of vitamin D to develop elevated blood pressure in later childhood.

Other risk factors can raise a child’s chances of developing high blood pressure, including inactivity and obesity.

The human body can produce its own vitamin D in the skin, but only when it’s exposed to ultraviolet (UV) radiation from sunlight or other sources.

“People who spend less time in the sun are more likely to have low vitamin D,” Audrey Koltun, RDN, CDE, a registered dietitian nutritionist in the department of pediatric endocrinology at Cohen Children’s Medical Center in New Hyde Park, NY, told Healthline.

To understand how vitamin D affected health from birth, the authors of the study followed a cohort of 775 children, from birth to age 18 years.

They tested samples of blood collected from participants’ umbilical cords at birth, as well as samples of blood collected in early childhood.

They also assessed medical data collected during routine checkups, including data about participants’ weight, height, and blood pressure.

In total, 44 percent of the participants had low levels of vitamin D in their cord blood at birth. Twenty-three percent of participants had low levels of vitamin D in early childhood.

Children who had less than 11 ng/ml of vitamin D in their cord blood were approximately 60 percent more likely than those with higher levels of vitamin D to develop elevated blood pressure between the ages of 6 and 18 years.

Among children who had less than 11 ng/ml of vitamin D in their cord blood, kids of mothers who were obese, had type 2 diabetes, or had high blood pressure were even more likely than others to develop elevated blood pressure.

Kids who were overweight or obese were also at increased risk of high blood pressure.

This research adds to a growing body of studies that have found links between low vitamin D and increased risk of high blood pressure.

It’s one of the only studies that have assessed this relationship from birth to later childhood.

All of the children in this study were recruited from Boston Medical Center in Boston, Massachusetts. Most of them were African American, low income, and residents of urban areas.

However, in order to learn if the findings hold true in other populations, more research is needed.

If these findings are confirmed in other studies, they suggest that treating vitamin D deficiency in pregnant women and young children might help reduce the risk of high blood pressure in later life.

“Currently, there are no recommendations from the American Academy of Pediatrics to screen all pregnant women and young children for vitamin D levels,” said the study’s lead author, Dr. Guoying Wang, PhD, in a press release issued by the American Heart Association.

“Our findings raise the possibility that screening and treatment of vitamin D deficiency with supplementation during pregnancy and early childhood might be an effective approach to reduce high blood pressure later in life,” Wang added.

According to the American College of Obstetricians and Gynecologists, most experts agree that it’s safe for pregnant women with vitamin D deficiency to take 1,000 to 2,000 international units (IU) of vitamin D supplements per day.

To learn how to prevent or treat low vitamin D, Koltun encourages pregnant women, parents, and others to speak with a registered dietitian nutritionist.

The American Academy of Pediatrics (AAP) reports that infants up to the age of 12 months require 400 IU of vitamin D per day. Children and adolescents over the age of 12 months require 600 IU of vitamin D per day.

The AAP recommends that infants who consume less than 1 liter of formula per day should receive 400 IU of daily vitamin D supplementation.

Some older children may also benefit from vitamin D supplements, particularly if they don’t drink a lot of fortified milk or eat a lot of foods that are rich in vitamin D.

Creating safe environments for children to play outdoors and encouraging them to spend time outside may also help prevent vitamin D deficiency.

“Really, what kids should be doing is running outside playing in the sunshine, rather than sitting indoors and playing video games,” said Dr. Barry Love, a pediatric cardiologist at Mount Sinai Hospital in New York.

“Obesity has been shown to be a big risk factor for high blood pressure, and if we got children to go outside and play in the sunshine, even with sunscreen on, that might help take care of the obesity problem and the vitamin D problem,” he added.

Vitamin D is essential, not only for cardiovascular health but also for the development and maintenance of strong bones.

There are multiple reasons that a person may not get enough vitamin D. People who live in northern regions are more likely than those in southern regions to have low levels of vitamin D, especially during cold winter months.

Black Americans are also more likely than white Americans to develop vitamin D deficiency, due to the higher levels of melanin in darker skin. Melanin is a pigment that absorbs UV radiation, reducing the synthesis of vitamin D.

When people wear sunscreen or cover their skin in clothing when they’re outdoors, that also reduces their skin’s exposure to UV radiation. That helps lower their risk of skin cancer, but it also reduces their synthesis of vitamin D.

Although vitamin D is found in some foods, such as eggs, fatty fish, fortified milk, and baby formula, it can be challenging for many people to get enough vitamin D from diet alone.

Among those who have low levels of vitamin D, taking daily supplements may be helpful.