The researchers also examined the women's blood and diet for levels of antioxidant nutrients, including vitamin E and beta-carotene, which are thought to protect against cancer.
The good news is that a diet rich in fruits and vegetables contains literally thousands of antioxidant nutrients.
And unless taken with vitamin E, large doses of fish oil can deplete the body's supply of this critical antioxidant nutrient.
It has been widely hailed as the most carefully designed investigation in people into the presumed protective role of supplements of antioxidant nutrients.
The evidence for the value of antioxidant nutrients, albeit strongly suggestive, is not proved.
"The present study reinforces the general recommendations of a lifelong diversified diet that includes an abundance of foods rich in antioxidant nutrients."
Red peppers, mangoes, carrots and purple grape juice The antioxidant nutrients in these foods may protect against heart disease and some cancers.
These individuals may also have been more likely to take supplements of other antioxidant nutrients.
Supplements including herbals, green tea extract, and added antioxidant nutrients are encouraged.
Black tea, green tea and coffee also contain antioxidant nutrients, which may protect against heart disease.