AGRONOMIC NEWS ITEMS
From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335
Fall 2002, No. 6
Functional foods have been defined as foods that may provide health benefits beyond basic nutrition. They contain biologically active components thought to enhance health and wellness. These components are not among traditional nutrients, i.e., carbohydrates, fats, proteins, minerals, and vitamins. Rather, they are phytochemicals such as lycopene in tomatoes, allicin in garlic, and isoflavones in soybeans. These phytochemicals or functional components may be extracted and consumed as supplements or may have therapeutic value when consumed in whole foods.
Functional foods and their active components are associated with the prevention and treatment of several leading causes of death, including cancer, hypertension, and heart disease. Additionally, they may provide help with other ailments including neural tube defects, osteoporosis, abnormal bowel function, and arthritis. Their modes of action are diverse, including antioxidant, anticarcinogen, probiotic, phytoestrogen, and anti bacterial activities.
The functional foods industry and market in the U.S. has expanded rapidly and has tremendous potential for further growth. Some estimate that annual functional food sales approach $20 billion and that yearly increases of 8 to 11 percent are not unreasonable. With this market firmly established, it stands to reason that there may be significant potential for adding value to some crops by enhancing the functional component content. Genetic manipulation of crops will likely play an important role. However, some management practices may also be important in affecting the concentration of active components.
Crop nutrition has been shown to influence functional components of some foods. For example, an early study demonstrated that total carotenoid (including lycopene) content of tomatoes generally increased with increasing amounts of potassium in nutrient solution. A more recent study in the Rio Grande Valley of Texas has shown that potassium nitrate produced grapefruit with higher vitamin C concentrations than the control. Additionally, fruits receiving potassium nitrate foliar spray treatments had significantly higher beta-carotene concentrations than the control. In Ontario, Canada, soybeans grown at various levels of fertility in several field trials were analyzed for potassium and total isoflavone content. These analyses revealed a positive relationship between potassium and isoflavone concentrations in the harvested soybeans. There was also a positive association across these sites between yield and isoflavone concentration. The results of this study suggest that when potassium is deficient for yield, it also limits isoflavones. In fact, high yield was positively associated with high isoflavone levels.
The medical and nutritional science communities have been investigating the health benefits of functional foods and their associated phytochemicals for years. However, research on the role of soil fertility and fertilization is in its infancy. Perhaps value added opportunities associated with functional components will be needed before widespread interest is generated. Nevertheless, crop and soil scientists must work toward improving grower economic viability and the health and nutrition of humankind. The current interest and trends in functional foods and their active ingredients may ultimately provide such an opportunity.