NUTRITION INFORMATION - ARTICLES
March 20, 2001, Produce for Better Health Foundation. 
Note to Editors: Twenty-ninth in a series of monthly 5-A-Day columns.
Asparagus Provides More Than You Might Think To a Meal:
How About Glutathione?
Gordon Wardlaw, Ph.D., R.D.,Associate Professor, Medical Dietetics Division, School of Allied Medical Professions, The Ohio State University, Columbus, Ohio 43210. Today fruits and vegetables enjoy much attention as part of a healthy diet. Aside from being low in fat, fruits and vegetables are rich sources of antioxidant nutrients such as various carotenes and vitamin C, as well as "other" compounds that likely slow the development of both cancer and heart disease. These "other" components often are called phytochemicals ("phyto" means plant). Phytochemicals aren't absolute requirements for diet planning, like the vitamins, but are beneficial parts of a diet nevertheless. Food sources of these substances also tend to be rich in dietary fiber, which alone provides many benefits to ones diet.
Asparagus is especially rich in antioxidant nutrients and phytochemicals. Vitamin A (present as various carotenes), vitamin C, and vitamin E are amply represented. Adding to this impressive list is the phytochemical glutathione. Body cells make glutathione; we also benefit from that present in the diet. Asparagus contains more glutathione than all other fruits and vegetables analyzed to date. (Freshly prepared meat are also an especially rich source.)
Glutathione deserves attention for a number of reasons:
It participates in a process which cells use to break down highly toxic peroxide and other high-energy, oxygen-rich compounds, in turn preventing them from destroying cell membranes, genetic materials (eg. DNA), and other cell constituents. Glutathione also participates in repair of damaged DNA.
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It can bind carcinogens in the body, aiding in their removal via the urine or feces.
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It participates in immune function.
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It can recycle vitamins C and E back to their active forms. In this way, glutathione may help reduce cataract development in the eye.
Numerous population studies show lower rates of many forms of cancer in people who consume a diet rich in fruits and vegetables. Regularly including asparagus in a diet provides a head start in gaining this benefit since asparagus is such a good source of the many antioxidant nutrients and phytochemicals - such as glutathione - that currently garner much of the limelight in nutrition research.
Asparagus is an important vegetable choice for another reason. It is best served lightly cooked: steamed is an ideal way to cook it. This light cooking preserves the glutathione content while prolonged cooking or canning of this or any fruit or vegetable leads to much destruction.
Given the epidemic of heart disease, cancer, and obesity in this country, many of us would benefit from a greater focus on fruits and vegetables in our diets. Asparagus is an excellent choice as part of the 5 to 9 servings of fruits and vegetables recommended by the Food Guide Pyramid.
REFERENCES:
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ADA Reports: Position paper or The American Dietetic Association: Phytochemicals and functional foods, Journal of the American Dietetic Association: 493, April, 1995.
- Greenwald, P.: Antioxidant vitamins and cancer risk, Nutrition 10 (5), p. 433, 1994.
- Jones, D.P. and others: Glutathione in foods listed in the National Cancer Institute's health habits and history food frequency questionnaire, Nutrition and Cancer 17 (1), p. 57, 1992.
- Marwick, C: Learning how phytochemicals help fight disease, Journal of the American Medical Association, 274 (17), p. 1328, 1995.
- Meister, A.: Glutathione, ascorbate, and cellular protection, Cancer Research (supplement), 54 (April), 1994.
- Richie, J.P.: The role of glutathione in aging and cancer, Experimental Gerontology, 27:615, 1992.
Asparagus is Rich in Folate - A Vitamin That Benefits The Body In Many Ways
- Gordon Wardlaw, Ph.D., R.D., Associate Professor, Medical Dietetics Division, School of Allied Medical Professions, The Ohio State University, Columbus, Ohio 43210
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