A US government study that tracked the nutrient levels in fruits and vegetables for 50 years has found today's offerings are less abundant in key nutrients than those of the 1950s.
The United States Department of Agriculture monitored 13 major nutrients in fruits and vegetables from 1950 to 1999 with six showing noticeable drop-offs — protein, calcium, phosphorus, iron, riboflavin and vitamin C. The declines ranged from 6 per cent for protein, 15 per cent for iron, 20 per cent for vitamin C, and 38 per cent for riboflavin.
Head researcher Donald Davis, a biochemist at the University of Texas, said the trend toward fast-growing and large-yielding crops was one reason for the decline, noting US fruit and vegetable productivity had increased dramatically in the past five decades. However, fast-growing plants aren't always able to acquire the nutrients slower-growing varieties can, either by synthesis or from the soil.
A Canadian study mirrored the US results, as did a UK study that analysed the nutrient content of fruit and vegetables going back to the 1930s. It showed that, on average, vegetables had lost about half of their sodium and calcium content, a quarter of their iron and 76 per cent of their copper content. The nutrient levels of fruits had also declined significantly with iron, copper and zinc all falling by up to 27 per cent.
Aileen Burford Mason, a Toronto-based biochemical nutritionist, said supplementation was an obvious means to fill the nutritional gap left by the dwindling quality of many modern foods. "When I hear people say they can get all the nutrients they need from food I ask them: Where is there a shred of evidence that is true? They are in denial," she said. "Taking a multivitamin is risk-free and could have tremendous benefit. No matter how well we eat, it's not possible to get adequate nutrition."