Rosemary Wander, Ph.D.

Associate Professor
Nutrition and Food Management

Although it is clear that Americans should maintain their fat intake at about 30 percent of their total calories, it is less clear what kind of fat should be consumed. Should one use corn oil, fish oil, or, as was used in previous generations, lard? Our research program has addressed this issue and, in particular, the role of fats found in fish oil on risk factors associated with heart disease.

The frequent consumption of fish has been linked to a decrease in mortality from heart disease. It is thought that this beneficial effect is derived from two specific fatty acids found in fish fat, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid. While there may be beneficial effects from eating these types of fat, there may also be negative effects, since these fatty acids have a molecular structure that makes them easily oxidized. In food, this leads to rancidity. In the body, oxidized fatty acids are associated with heart disease, aging, diabetes, and cancer.

It is thought that this oxidative process can be prevented or slowed with vitamin E, but the amount required for this is not known. Consequently, we conducted a study with 48 postmenopausal women, since they have a risk of heart disease as high or even higher than males of a similar age, and we have very little knowledge about factors to modify their risk. All of the women were given a daily supplement of fish oil containing an amount comparable to that present in a 6-ounce serving of Chinook salmon. The women were divided into four groups and given a vitamin E supplement. During the study all groups received, but in a different order, no extra vitamin E, 100 IU, 200 IU, or 400 IU each day.

The amount of vitamin E in blood was measured after taking the supplements. The smallest dose of vitamin E, 100 IU, increased the amount in the blood greatly but the next two doses, 200 and 400 IU, only slightly increased the amount. The ability of the vitamin E to decrease the oxidation of the fatty acids in the consumed fish oil was measured in five ways. Only two indicated that there was a benefit in taking the vitamin E supplements. Collectively, these data suggest that vitamin E supplements are of limited usefulness in the protection from increased oxidation when fish oil is consumed.

In our laboratory, we are also studying the role of EPA and DHA on the immune response, the role of the fatty acids in olive oil on risk factors for heart disease in Type II diabetic postmenopausal women, cardiovascular risk factors in premenopausal black and white women, and the fat content of breast milk from women from New Zealand and China.Last updated November, 1996

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