Cell-damaging substances known as oxygen free radicals may be to blame for hardening of the arteries that often occurs in women later in life, according to new study findings.

Moreover, this oxidative damage appears to be strongly linked to increases in abdominal fat and levels of LDL (“bad”) cholesterol.

Study author Dr. Kerrie L. Moreau explained that free radicals are a normal byproduct of metabolism, and we have natural mechanisms to protect us from free radicals. One such mechanism is estrogen, which acts as an antioxidant, she said.

The latest findings suggest that when women lose estrogen after Menopause, their bodies are no longer capable of fending off the damage free radicals can inflict on their arteries, causing them to stiffen, she said.

Giving the postmenopausal women in the study a high dose of antioxidant reversed that process, noted Moreau, who is based at the University of Colorado at Boulder.

Arterial stiffness can be dangerous if it prevents the arteries near the heart from expanding when the heart pumps out blood, Moreau explained. If the arteries cannot expand, the heart has to pump harder to get enough blood around the body; over time, this will weaken the heart, leading to high blood pressure and even Heart failure, she said.

“So you want to keep (blood vessels) nice and elastic,” she said.

Previous studies have suggested that women’s blood vessels tend to get stiffer with age. To investigate why, Moreau and her team measured arterial stiffness in 31 healthy, but sedentary, women. Twenty-one women had gone through menopause.

Reporting in the journal hypertension, Moreau and her team found that postmenopausal women’s arteries were significantly stiffer than the arteries of premenopausal women.

After giving women an extremely high dose of vitamin C - a potent antioxidant - the investigators found that postmenopausal women’s arteries became significantly more elastic. However, the vitamin C had no effect on the arteries of premenopausal women.

Moreau explained that the greatest effect of the vitamin C was seen in women who had relatively high levels of LDL cholesterol, and if they had extra fat stored in their abdomen. This suggests that these women may produce extra amounts of free radicals, which can be neutralized by vitamin C, Moreau noted.

She emphasized that the women in this study received an extremely high dose of vitamin C, and women should not expect a standard supplement of the vitamin to protect their arteries from damage. Moreau said she “strongly cautioned” women against taking vitamin C for this purpose.

For now, Moreau recommended that women try exercise to keep their blood vessels in good shape, since research has shown that women who exercise experience less arterial stiffness than women who don’t.

SOURCE: Hypertension, 2005.