Diminishing nutritional returns Part 1             

            When the first farmer harvested his second crop it was not as nutritious as the first. To be sure, the loss of nutrients was minuscule but it started a trend that has accelerated in the past century. Early agriculturalists eventually learned that tilled soil must be replenished with compost and croplands must be rested periodically. In the 19^th century chemical fertilizers came into wide use but they did not return all nutrients to the soil. Mechanized farming required selection of varieties of fruits and vegetables that were uniform in size and shape for easy harvesting. The long-distance transport of produce made it necessary to develop crops that were hardy enough to withstand days of travel and storage. These agricultural advantages led to a dramatic reduction in the variety of cultivars and the diminution of nutrient content.

            The United States Department of Agriculture and several universities have monitored nutrients in plant foods for several decades. The decline has been steady and sometimes dramatic. It has affected cereal grains as well as fruits and vegetables.

            The primary source of dietary calcium in the United States is dairy products but before the Agricultural Revolution humans obtained this mineral from plant foods. In many parts of the world where there is no large dairy industry, as in Africa and most of Asia, plant foods are still the primary source of calcium. Since 1975 the calcium content of some vegetables and fruits in this country has diminished by about 50 percent; in the case of corn it is 78 percent. As developing countries make the transition to modern farming techniques they may experience the same problem.

            The mineral content of some foods has dropped significantly. Iron, magnesium and potassium have fallen by as much as 88 percent among plants such as collard greens and watercress, which have been recommended for their high content of these minerals. Vitamins A, C and riboflavin (vitamin B2) have diminished by 30 to 40 percent in some studies.

            Flavor and texture have also fallen victim to the industrialization of agriculture. Stone fruits such as peaches and apricots need to be picked before becoming ripe in order to look good after a couple of days on a truck. An out-of-season Fuji apple has usually crossed an ocean. Bananas need to be picked when green but their flavor and texture suffer as a result.