Diets high in antioxidants may curb women’s stroke risk

By Sophie Ramsey

BMJ Group News

What do we know already?

Antioxidants are nutrients that help to protect your cells from damage caused by ‘free radicals’ - harmful molecules that may play a role in heart disease, cancer, and other illnesses.

There are lots of different types of antioxidants, including vitamin C, vitamin E, carotenoids, and flavonoids. They are found in many foods - including nuts, grains, and some meat - but are most plentiful in fruit and vegetables.

What role antioxidants might play in preventing strokes hasn’t been widely studied. However, research suggests these nutrients - particularly flavonoids - may protect blood vessels from damage and stiffening, and reduce blood clots, blood pressure, and inflammation.

In the new study, researchers followed 36,715 Swedish women (aged 49 to 83) for around a decade to find out whether the antioxidant levels in their diets were linked to their risk of having a stroke. At the study’s start, the women filled in detailed questionnaires on their health, lifestyle, and how often they’d eaten numerous foods over the last year, including 30 that were high in antioxidants. Each woman’s diet was then scored for its ‘total antioxidant capacity’.

The researchers looked both at women who were free of heart disease and those who had a history of heart disease.

What does the new study say?

Among women with no history of heart disease, higher antioxidant scores were linked to a lower risk of stroke. For women with the highest scores, 4 percent had a stroke during the study, compared with 5 percent of those with the lowest scores.

After accounting for other factors that might have affected the women’s stroke risk (such as whether they smoked or were overweight), the researchers estimated that women with the highest scores had a 17 percent lower risk of a stroke.

For women with a history of heart disease, higher antioxidant scores were also linked to a lower risk of stroke, but the difference was small enough that it may have been down to chance.

However, researchers found a stronger link when they looked only at hemorrhagic strokes, which occur when a blood vessel bursts in the brain. Dividing the women into four groups based on their antioxidant scores, the researchers found that 3 percent of women with the lowest scores had a stroke, compared with between 1 percent and 2 percent of women in the other three groups.

After accounting for other risk factors, they estimated that women with higher antioxidant scores had a 46 percent to 57 percent lower risk of a hemorrhagic stroke.