Antioxidants may control dangerous blood pressure
By Colette Bouchez
TUESDAY, May 1 (HealthScout) — If you’re pregnant, keeping your body high in antioxidants may help you avoid a condition where your blood pressure rises rapidly and threatens not only your life but your baby’s as well.
That’s the finding presented by a group of New York researchers at today’s session of the 50th annual meeting of the American College of Obstetrics and Gynecology in Chicago.
Doctors from Bronx-Lebanon Hospital Center in New York offered compelling evidence that women with low levels of certain carotenoids in their blood and placenta were much likelier to develop preeclampsia than women whose levels were normal. Carotenoids are natural pigments that act like antioxidants in protecting cells against free-radical oxygen damage.
“We measured the concentrations not only in the blood, but also in the placenta itself because most changes in preeclampsia happen because of decreased blood supply to the placenta,” says lead study author Dr. Magdy Mikhail. The placenta is the tissue that surrounds the baby during pregnancy and through which nutrients are fed from mother to fetus.
But why focus on antioxidants?
“The reasonable explanation here is that in preeclampsia, there is an increased production of free radicals by the placenta, which is why we suspected that antioxidant levels would be decreased,” says Mikhail.
To put the antioxidant theory to the test, doctors measured levels of four carotenoids — alpha and beta carotene, lycopene and canthaxanthin. They tested the levels in maternal blood, umbilical cord blood and in the placenta in 22 women with normal pregnancies and 19 who were already diagnosed with preeclampsia.
While all four carotenoids were found in the placental tissue, levels in the women with preeclampsia were much lower than those in women who were having a normal pregnancy. Interestingly, while umbilical cord blood levels were the same in both groups, maternal blood levels of both carotenes and lycopene matched the lower levels found in the placental tissue of these same women.
“Our findings suggest that oxidative stress and placental antioxidant levels may play a key role in the development of preeclampsia,” says Mikhail.
Dr. Phyllis August agrees. She is chief of the division of hypertension at New York Weill Cornell Medical Center and says that past studies have come up with similar findings.
“There have actually been a couple of clinical trials where they have administered high levels of antioxidant vitamins — vitamin A and vitamin C — to women at risk for preeclampsia, and they had some beneficial results,” she says.
And while she cautions that these new findings were just observations and not a clinical trial, still, August says, “If everything was done correctly, then it’s one more piece of the antioxidant-oxidative stress puzzle as a possible mediator for preeclampsia.”
But how, exactly, do these deficiencies lead to high blood pressure? The link, says Mikhail, is free radicals — nasty molecules that cause a biochemical chain of events resulting in oxidation, a process that eventually damages healthy cells.
“It’s causing changes in the cells of the blood vessel walls that either lead to a decrease in substances that prevent blood pressure from rising, or increase production of substances that cause blood pressure to rise,” adds August.
What To Do
If, in fact, antioxidants are proven to be the catalyst in this biochemical chain of command, then these same nutrients may not only benefit pregnant women, but all people at risk for hypertension.
Currently, the American College of Obstetrics and Gynecology advises all pregnant women to take a prenatal vitamin containing antioxidants. In addition, they advise eating lots of fresh fruits and vegetables, the best sources of antioxidant protection.
“If you start with a good supply of these nutrients going into your pregnancy, then eat well while you are pregnant, the higher your stores of antioxidants will be — so your body is better able to counteract any excess production of free radicals caused by the placental tissue,” says Mikhail.
Foods that have the highest levels of the antioxidants featured in this study include brightly colored fruits and vegetables such as tomatoes, carrots, cantaloupe, apricots and peaches.