Researchers studying pregnant women found that black women with a dangerous high blood pressure complication had less folic acid and more of a certain amino acid than white women.
The difference could help explain why black women are at higher risk for the life-threatening complication, pre-eclampsia. And it suggests they should take higher doses of the vitamin, folic acid.
The finding also could indicate future risk for cardiovascular disease.
Pre-eclampsia affects 3 percent to 5 percent of pregnant women and is a common cause of premature births. It typically occurs very late in a pregnancy.
Besides inducing high blood pressure, it can cause kidney failure, swelling of hands and feet, seizures and death.
In the United States only a few hundred women die from pregnancy-related causes each year, but pre-eclampsia kills thousands in developing countries.
Researchers have long known that black women have higher incidences of pre-eclampsia, but they have yet to pinpoint why.
"We know that when black woman experience the disorder, they are more likely to have a more severe form that shows up as early as six months into pregnancy,'' said lead researcher Thelma Patrick, an assistant investigator at the Magee-Women's Research Institute in Pittsburgh.
"We've been looking at biochemical evidence to help us understand why they're at higher risk.''
The researchers examined whether black women have pre-existing risk factors for pre-eclampsia.
The findings in Tuesday's issue of Hypertension: Journal of the American Heart Association suggest those risk factors could be low levels of folic acid and high levels of homocysteine, an amino acid linked to heart disease.
Researchers examined 85 white women and 78 black women. Thirty-four white women and 26 black women had pre-eclampsia. Blood samples were taken from each woman near delivery time and were tested for biochemical differences.
The findings revealed that homocysteine was higher in all the women with pre-eclampsia. But black women with the condition had the highest levels of all.
Black women also had lower levels of folic acid compared to white women, but higher levels of B12 than white women. Patrick said that finding was interesting because both folic acid and B12 are needed to break down homocysteine.
She said other studies have shown that high homocysteine levels are linked to diets low in folic acid and vitamins B6 and B12, but her study wasn't able to determine whether the differences in the women were related to diet, lifestyle or heredity.
However, the findings strongly suggest that black women might need to take more folic acid, she said.
Black women have typically been low in that vitamin, which is found leafy green vegetables such as spinach, turnip greens and kale.
In the United States, it is also added to cereal and flour products, primarily because it helps prevent birth defects. Patrick said more studies are need to solidify the study's findings.
Dr. Jennifer Mieres, a cardiologist at New North Shore University Hospital in New York, described the study as provocative "because it calls our attention to our lack of knowledge about this very important problem.''
Mieres said it shows that homocysteine might be related to the cause of pre-eclampsia. Both homocysteine and folic acid can be treated, and the study's findings could possibly lead to testing pregnant women for both, she said.
The study also could open the doors for more cardiovascular research. Studies have shown that too much homocysteine is related to a higher risk of coronary heart disease and stroke, and women, particularly black women, have a higher risk of cardiovascular disease, she said.
"It's a wake-up call for us,'' Mieres said. "Pre-eclampsia is still a force to be reckoned with.''