Modern farmers can grow food in abundance, but over the years there has been a steady decline in the nutritional content of food produced globally. Analysis of a U.S. Department of Agriculture (USDA) report on over 40 common fruits and vegetables has revealed that around 50 percent of the substances containing vitamins and minerals essential for optimal human health suffered a considerable decline in nutrient content between the years 1950 and 1999. The nutrients identified as having lost the most value were phosphorus, protein, calcium, iron, vitamin C and vitamin B2, with declines ranging from 6 to 38 percent. Scientists believe that two factors — industrial farming practices and crop selection strategies — may have contributed to the decline.

The Effect of Modern Farming Practices

Modern farming techniques, such as fertilization and pesticide use, help crops to grow faster and larger, but they appear to reduce their nutritional value. Fertilizers provide crops with the three minerals they require for growth, but when used excessively, they seem to raise the levels of some of the crops’ innate minerals while lowering the levels of others. A recent study into the effect of a phosphorous-rich fertilizer on the nutritional value of raspberries has helped to demonstrate this point. It revealed that the phosphorous concentration of the raspberries increased at the expense of eight other minerals, whose declines ranged from 20 to 55 percent. In addition, scientists believe that the overuse of soil by farmers is having an effect on the nutritional value of crops. Some varieties take too many important nutrients from the soil, and over time, this can cause the soil to lose its ability to provide nutrient-rich yields.

The Effect of Crop Selection

The other force responsible for the nutritional decline in crops is genetic dilution, which occurs when farmers select high-yielding crops over nutrient-dense varieties. Crops grown to provide generous yields often lack the energy required to produce nutrients, and when farmers spray them with fertilizers and pesticides, the result is a further reduction in their nutritional value.

The Consequences for Consumers

Scientists concerned by the nutritional depletion of crops are urging farmers to limit their use of pesticides and fertilizers and to alternate the use of their fields to give their land time to recover from the effects of farming. They are also keen to encourage consumers to continue to eat fruits and vegetables as, despite containing fewer vitamins and minerals than they used to, these flavorful foods can go a long way towards helping prevent diet-related diseases such as type 2 diabetes and heart disease.