Fruits, vegetables, and their combination of nutrients and phytonutrients likely play a role in preventing or delaying the development of age-related chronic diseases, like cancer and cardiovascular disease. The 2010 Dietary Guidelines recommend that most people consume 2 cups of fruit and 2.5 cups of vegetables per day.
Phytonutrients are natural compounds derived from plants that can have health benefits when consumed. As opposed to nutrients, omission of phytonutrients in the diet will not cause deficiency symptoms, but including them can have additional health benefits. Some examples include anthocyanins in berries, capsaicin in peppers, and carotenoids in melons, carrots, tomatoes, sweet corn, green leafy vegetables, and green beans.
How Cooking or Preserving Can Impact Nutrient and Phytonutrient Levels
Cooking and preservation exposes the fruit or vegetable to heat, oxygen and light, all which can degrade nutrient and phytonutrient levels. How do you maximize the levels in your food? Keep reading:
- Boiling—Shorter cooking time minimizes nutrient loss. Consume cooking water or save for later, such as in soups or for cooking rice.
- Steaming—Minimal contact with water helps retain water-soluble nutrients. Light steaming improves the availability of nutrients and phytonutrients.
- Sautéing—Lower temperatures and shorter cooking times minimize nutrient loss. Lack of water during cooking reduces loss of water-soluble nutrients. A small amount of oil can increase availability of carotenoids.
- Roasting or grilling—Compared to other cooking methods with lower temperatures, may result in a higher nutrient loss.
- Canning—Can improve absorption of lycopene (a carotenoid) from tomatoes. Can cause loss of vitamin C.
- Freezing—Results in high nutrient retention. Blanching (briefly boiling) can have small loss of heat-sensitive and water-soluble nutrients.
- Drying—Loss of all water-soluble nutrients, but retains fiber. To maximize nutrient and phytochemicals, a different preservation method is advised.
This information is not meant to diagnose, treat, cure or prevent any disease. This project is made possible by funding through OSU CARES—an initiative of OSU Extension and The Ohio State University to expand faculty, staff and student partnerships with communities throughout Ohio.
Ohio Produce: Nutritional Powerhouses
Ohio produce have many health promoting vitamins, minerals and phytonutrients. USDA's MyPlate model suggests that consuming a variety of fruits and vegetables is a key to good health, since nutrients often work together.
- Beets have significant sources of folate, potassium and phytonutrients called betalains, compounds that may prevent the development of heart disease and certain cancers.
- Cruciferous vegetables (leafy vegetables, broccoli) contain vitamin A, vitamin C, folate, and phytonutrients called glucosinolates. Many of these compounds may provide cancer protection, especially for the bladder and prostate.
- Green beans and pea pods have vitamin A, vitamin C, folate and phytonutrients including carotenoids, chlorophyll, polyphenols and saponins. These compounds may prevent development of heart disease and cancers.
- Sweet corn contains vitamin C, niacin, and carotenoids. The compounds in sweet corn are antioxidants and have been demonstrated to slow digestion and control blood sugars.
- Tomatoes contain vitamin A, vitamin C, vitamin K, potassium, and carotenoids. Tomatoes may provide protection from heart disease and certain cancers, especially prostate.
- Green leafy vegetables contain vitamin A, vitamin E, vitamin K, vitamin B6, riboflavin, folate, magnesium, iron, calcium and potassium. Phytonutrients include carotenoids and polyphenols. Compounds in leafy vegetables may prevent cancers and promote bone health.
- Peppers have vitamin A, vitamin C, vitamin B6, carotenoids, phenolics, and capsaicin. Compounds found in peppers may provide cancer protection and improve cholesterol.
- Winter squash, pumpkins and carrots contain vitamin C, vitamin A, vitamin K, vitamin B6, potassium and carotenoids. These compounds are antioxidants, and anti-inflammatory. Health benefits include possible cancer protection and blood sugar control.
- Apples, pears and peaches have vitamin A, vitamin K and the phytochemical quercetin, which are all anti-inflammatory.
- Berries contain vitamin C, vitamin K, and have the phytonutrients anthocyanins and ellagitannins. Many of these are anti-inflammatory compounds and are thought to provide cancer protection, especially of the mouth, esophagus, intestine and prostate.
- Melons contain vitamin C, vitamin A, vitamin B6, folate, potassium, carotenoids and polyphenols. These compounds may prevent the development of heart disease and certain cancers.
- Rickman, J. C., Bruhn, C. M., & Barrett, D. M. (2007). Nutritional comparison of fresh, frozen, and canned fruits and vegetables II. Vitamin A and carotenoids, vitamin E, minerals and fiber. Journal of the Science of Food and Agriculture. doi:10.1002/jsfa.2824
- U.S. Department of Agriculture, A. R. S. (2011). No Title. Retrieved July 23, 2012, from Nutrient Data Laboratory Home Page, ars.usda.gov/ba/bhnrc/ndl