Fruits contain a host of vitamins and minerals that support healthy functioning of your respiratory and immune systems. Many of these nutrients have antioxidant properties that can help prevent cellular damage caused by free radicals and exposure to environmental contaminants such as second-hand smoke. The USDA's Dietary Guidelines for Americans strongly urges Americans to increase their dietary intake of fruits.
Cantaloupe
Cantaloupe contains high amounts of two vitamins essential for immune system function. A 1-cup serving of diced cantaloupe contains two-thirds of the recommended daily allowance of vitamin A for women and over one-half for men. Vitamin A is essential for maintaining the health of your skin, your body's primary defense against disease-causing microbes. It also contains over 75 percent of the RDA for vitamin C for adult women and nearly two-thirds of the RDA for adult men. Vitamin C helps in the healing of wounds to prevent the spread of infections.
Orange
Oranges provide an excellent dietary source of vitamin C. In addition to promoting wound healing, vitamin C may also improve respiratory system function. A study by the University of Bergen in Norway, published in the February 2003 issue of “Respiratory Medicine,” found that high intake of dietary vitamin C improved smoking-related symptoms such as morning cough and chronic cough in young adult participants. A small orange provides about three-quarters of the RDA for adult women and over one-half for adult men.
Strawberry
Strawberries are another high-quality source of vitamin C. A cup of sliced berries contains over 100 percent of the RDA for both adult men and women. Adequate vitamin C intake supports healthy lung function. A study by the University of Nottingham in the United Kingdom, published in the May 2002 issue of the “American Journal of Respiratory and Critical Care Medicine,” found that high vitamin C intake not only improved lung function, but could also prevent chronic obstructive pulmonary disease.
Grapefruit
Grapefruit, like the orange, provides a healthy source of both vitamins A and C. A cup of grapefruit sections provides over 70 percent of the RDA for vitamin A for adult men and women. Vitamin A plays several roles in immune system function. In addition to skin health, it also helps maintain the well-being of your mucosal cells that line your airways and digestive tract. This nutrient is also essential for the differentiation of white blood cells. There are five main types of white blood cells, each specialized for a certain task. This diversity in roles is vital for good health.
References
- USDA Center for Nutrition Policy and Promotion: Dietary Guidelines for Americans, 2010 - Foods and Nutrients to Increase
- U.S. Department of Agriculture Nutrient Data Laboratory
- Linus Pauling Institute; Vitamin A; Victoria J. Drake; November 2007
- Linus Pauling Institute; Vitamin C; Victoria J. Drake; November 2009
- “Respiratory Medicine"; Dietary Vitamin C Intake Is Inversely Related to Cough and Wheeze in Young Smokers; E. Omenaas, et al.; February 2003
- "American Journal of Respiratory and Critical Care Medicine"; Prospective Study of Diet and Decline in Lung Function in a General Population; T. McKeever, et al.; May 2002
