Take C or Not Take C, That Is the Question
April 27, 2000 -- A new study from the U.K. confirms previous research
showing vitamin C supplements can lower blood pressure. But other research
shows that vitamin C supplements also might harden the arteries, increasing the
risk for heart attack or stroke. So what should you do?
"I believe vitamin C from a balanced diet is much better for people than
popping capsules," says study co-author, Martin D. Fotherby, MD.
Blood pressure is the force of the blood pushing against the walls of
arteries each time the heart beats. When the heart contracts and pumps blood
the pressure it exerts on blood vessel walls is called systolic pressure. The
pressure on the vessel walls between beats is called diastolic pressure. Blood
pressure is always given as these two numbers, systolic and diastolic
pressures. Usually they are written one above the other, for example 120/80
mmHg, with the top number the systolic pressure, and the bottom the diastolic
In the new study conducted at The Glenfield Hospital in Leicester, 40 adults
all between the ages of 60 and 80 with slightly elevated blood pressure were
given 250 mg of vitamin C capsules twice a day for three months. At the end of
the study researchers noted a small but significant fall in systolic blood
pressure but not in diastolic blood pressure. The study appeared in the May
2000 issue of the Journal of Hypertension.
Fotherby, who is a senior lecturer at the University of Leicester, in
England, says the dose of vitamin C used in this study, 500 mg per day, is
substantially larger than the level recommended for healthy adults. For some
time, that amount was 60 mg, but the Institute of Medicine in the U.S.
recommended it be raised to 75 mg per day for women and 90 mg per day for men.
According to the American Dietary Association (ADA) one 8-ounce serving of
orange juice contains about 97 mg of vitamin C.
Fotherby concluded that the results confirmed previous research showing a
relationship between higher vitamin C intake and lower risk of cardiovascular
disease and stroke. Most recently, two studies at the Boston University School
of Medicine showed that the average systolic pressure of the subjects had
fallen after one month of taking 500 mg of vitamin C.
On the other hand, recent research conducted at the University of Southern
California and presented at an American Heart Association meeting showed that
men who took 500 mg of vitamin C developed thickening of their artery walls,
increasing their risk of heart attacks or strokes.
So how can vitamin C both reduce blood pressure and harden the arteries?
Fotherby says no one really knows, but he has a theory. "Although we gave
capsules to the subjects in our study, food sources of vitamin C are far
superior," says Fotherby. "Since foods contain many other nutrients,
including other antioxidants, they work together to promote overall