Bad news and worse news about fruits and veggies 03/12/2004 OTTAWA — Many vegetables and some fruits really have declined in quality in the past 50 years as crop breeders put size ahead of nutrition, a study from Texas suggests. The University of Texas at Austin analysed 43 common “garden crops” and found widespread declines in their content of vitamins B and C, iron, calcium and other nutrients. The scientists say this reinforces earlier findings from Britain , and raises questions about the wisdom of modern farming practices that focus too much on size. “During those 50 years, there have been intensive efforts to breed new varieties that have greater yield, or resistance to pests, or adaptability to different climates. But the dominant effort is for higher yields,” said lead author Donald Davis of the university's department of chemistry and biochemistry. “Emerging evidence suggests that when you select for yield, crops grow bigger and faster, but they don't necessarily have the ability to make or uptake nutrients at the same, faster rate.” The scientists compared U.S. Department of Agriculture analyses of fruits and veggies from 1950 with others grown in 1999. Most were vegetables, but they also looked at melons, rhubarb and strawberries. Davis acknowledged there are difficulties in comparing data taken nearly 50 years apart, partly because lab techniques have changed. For that reason, he says, it doesn't make sense to list changes for individual species of vegetables. These may not all be reliable. But he says the overall picture, averaged across all 43 crops, is “on firmer footing.” “Considered as a group, we found that six out of 13 nutrients showed apparently reliable declines between 1950 and 1999,” he said. Those six were protein, calcium, phosphorus, iron, riboflavin and ascorbic acid (vitamin C). The biggest decline was in riboflavin, one of the B vitamins, which fell by 38 per cent. Vitamin C content fell an average of 20 per cent across the group. The smallest decline was in protein, down six per cent. And some individual declines can be charted fairly accurately, he believes. Today's tomato has 40-per-cent less vitamin C, 40-per-cent less protein and 40-per-cent fewer minerals than the 1950 tomatoes. “If we had been able to study flavour, might it have been on that list, too?” he wonders. “Perhaps more worrisome would be declines in nutrients we could not study because they were not reported in 1950 — magnesium, zinc, vitamin B6, vitamin E and dietary fibre, not to mention phytochemicals,” he said. He is now calling for research into other foods, including meats, milk, grains and eggs. But it's not all doom and gloom. Today's carrots are more orange than their great-granddaddies were, and the extra beta-carotene that brings this colour has doubled their content of vitamin A. Modern crop varieties are only half the story, says Tom Manley, who operates Homestead Organics in Berwick, southeast of Ottawa . He says farming methods can also contribute to loss of nutrition. Chemical fertilizers and pesticides rob the soil of microscopic organisms that are crucial to helping crops absorb nutrients, he says. “Organic foods tend to produce less volume — somewhere around threequarters of the yield [compared with conventional growing] — but we're observing better taste, and from certain reports we've read that the nutritional values are higher.” “Organic farmers rely on a greater variety of nutrients that build quality.” In Texas , Davis said his team undertook the study because of questions from organic farmers. “They are quite concerned about possible changes in our foods because of changes in the intensity of agriculture,” he said. Modern fertilizers “just have a few elements in them and not the broad range of nutrients that are in things like manure,” he said. As well, there were questions about whether soil is being stripped of nutrients by farm chemicals. Vegetables in the study included asparagus, green beans, beets, broccoli, carrots, cauliflower, corn, cucumber, head lettuce, onions (both mature and green), peas, potatoes, sweet potatoes, spinach, tomatoes, turnips and a variety of squashes. |