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United States Department of Agriculture

Agricultural Research Service


item Bruce, Bonnie
item Spiller, Gene
item Klevay, Leslie
item Gallagher, Sandy

Submitted to: Journal of American College of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Phytochemicals are substances occurring in plants that are not nutrients in the usual sense but may have beneficial effects on health of people who consume them regularly. A dozen women with high values for serum cholesterol were provided a typical Western diet heavily based on refined foods and low in fruits and vegetables for a month and then were provided with a plant-rich diet with minimally processed foods such as orange and green fruits and vegetables, whole grains, raisins, nuts, seeds and olive oil for another month. Although total fat and energy intakes were similar in the two diets, the latter diet had more fiber, vitamins E and C and carotenes, and less saturated fat. As expected cholesterol and other lipids in blood changed in more healthy directions with the unrefined diet. Activities of enzymes that protect against oxidative damage also decreased. These enzyme changes indicate that the plant rich diet provides a defense against oxidative damage that decreased the need for the body to provide this defense. Oxidative damage is thought to contribute to heart disease and some forms of cancer.

Technical Abstract: Certain whole and unrefined foods such as sun-dried raisins, nuts, sesame seeds, whole grains, and green/orange-fleshed vegetables and fruits contain high amounts of antioxidant phenolics, fibers, and other phytochemicals recognized as being protective against chronic disease (1,2). High rates of some cancers, heart disease, and poor colon function are related to typical Western diets high in animal foods, and refined grain products (3,4). To study the effects of a typical Western diet (TWD) and a plant-rich diet (PRD) based on whole and unrefined foods on lipoproteins, antioxidant defenses, and intestinal function, 12 hyperlipidemic women, 34-84 years old, for four weeks consumed a diet high in refined and animal foods and low in fruits and vegetables, and then for four weeks consumed a diet rich in unrefined and minimally processed foods, such as orange and green fruits and vegetables, whole grains, sun- dried raisins, nuts, sesame seeds, and olive oil. Energy and fat intakes were similar for both diets with saturated fat dropping by 61% and fiber increasing by 160% on PRD. Vitamin E, vitamin C and carotenes increased by about 145%, 160%, and 500%, respectively. The PRD induced a drop of 16% (p<0.00l) in low density lipoprotein (LDL-C) and 19% (p=0.08) in triacylglycerols (TG), with no change in high density lipoproteins (HDL-C). throcyte superoxide dismutase decreased by 69% (p<0.01) and glutathione peroxidase dropped 35% (p<0.01). Colon function was improved on the PRD. These changes indicate that the PRD deceased the need for oxidative defense mechanisms while inducing salutary effects on lipoproteins and colon function.

Last Modified: 10/16/2017
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