AGRONOMIC NEWS ITEMS
From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335
Fall 1998, No. 1
Tomatoes, soybeans, oats, blueberries, broccoli, and garlic are a few examples of functional foods. Lycopene, isoflavones, limonene, allicin, melatonin, and sulphoraphanes represent some of the many nutraceutical compounds they contain. The effects of many of these compounds are as yet poorly understood, but are considered important. For example, the therapeutic value of oat bran has been officially endorsed by the U.S. Food and Drug Administration.
Medical research suggests that lycopene may reduce cancer risk. Today, genetic engineering is promising new varieties of tomatoes with doubled lycopene content. More than 25 years ago, research showed that potassium fertilization could increase tomato lycopene by as much as 60 percent.
Soybeans contain isoflavones, thought to be powerful agents for disease prevention and cancer risk. Research in Canada has shown that soybean isoflavone content can vary more than three-fold, depending on the variety and the growing conditions. Soil fertility levels could certainly have an impact.
Phytate is another example of a food component being modified by biotechnology. Low phytate seeds of corn, barley, and rice have been developed, but research is still ongoing to develop a full understanding of the implications of low phytate for human health. While phytate is an anti-nutrient in terms of availability of phosphorus, zinc, iron, calcium, and magnesium, it has been found to have benefits as well, in reducing risk of prostate cancer.
A question that often arises is: "Do foods produced from today’s high-yield crops have the same nutritional quality as those grown long ago?" Many worry that fertilizing produces "empty calories" rather than healthy food. Is this true? It’s hard to find a general answer, but one recent study in Norway compared the nutritional quality of carrots produced on 10 organic farms with those on 10 farms using commercial fertilizer. No differences were found in trace elements, vitamins or taste perception, except that the carrots grown with fertilizer had higher beta carotene. This is not surprising, since other experiments have shown that carotene is enhanced by both nitrogen and potassium fertilizers. In many vegetables and fruits, potassium increases vitamin C content as well.
Worldwide, fertilizer use has boosted the amount of calories available per capita, but micronutrient deficiencies remain widespread. In fact, it is estimated that 2 billion people are malnourished in trace elements and vitamins. There is a need to do a better job of supplying a nourishing diet. Agronomists can help by:
• recommending appropriate application of micronutrients such as zinc or manganese where required
• pointing out micronutrient-dense and nutraceutical-rich species and varieties of food crops
• paying attention to the growing conditions and crop rotations that impact crop nutritional content
• increasing production of vegetables, fruits, and legumes