Remember picking green beans on Granny's farm and feeling confident in their homegrown goodness? Well, the nutritional value of fruits and vegetables has dropped in the past 50 years. Some researchers argue this nutritional slump is caused by the current agricultural trend of growing large-yielding crops fast, which doesn't give plants enough time to synthesize or obtain maximum nutrients from the soil.
Remember picking green beans on Granny's farm and feeling confident in their homegrown goodness? Well, the nutritional value of fruits and vegetables has dropped in the past 50 years, according to analyses from the US, the UK, and Canada, too.
In 2002 Canadian media examined tables listing food nutrient values going back to 1951 and compared them to values reported for produce in Canadian supermarkets in 1999. Of the 25 popular fruit and vegetable varieties tested, including potatoes, tomatoes, bananas, and apples, most showed a loss in nutrients, some significantly. Potatoes had lost all their vitamin A as well as 57 percent of their vitamin C and iron, while broccoli's calcium and iron had fallen 63 and 34 percent, respectively.
Some researchers argue this nutritional slump is caused by the current agricultural trend of growing large-yielding crops fast, which doesn't give plants enough time to synthesize or obtain maximum nutrients from the soil. Another factor is the tendency for produce to be picked too soon and shipped before it reaches full ripening.
Is Organic More Nutritious?
So what about organic food? Is it more nutritious? Charles Benbrook, chief scientist at the Organic Center and a former executive director of the Board on Agriculture of the US National Academy of Sciences, states: "All our data shows that whenever there's been a valid comparison between conventional and organic, organic is virtually never lower [nutritionally] than conventional, and in a significant number of cases, it's higher."
The Phytochemical Rainbow
Vitamins and minerals aside, "there are other beneficial compounds in fruits and vegetables," points out Dr. Hoon Tan, a medicinal chemist. He's talking about phytochemicals all those colourful reasons we're encouraged to eat a rainbow of veggies.
These antioxidants prevent cell damage and help ward off aging and degenerative diseases, including the two biggies, heart disease and cancer. Interestingly, Dr. Tan and his colleagues are finding more of them in organic produce.
"They're part of a plant's defence mechanism against disease and pathogens," he explains by phone, "so if crops are sprayed by agrochemicals, they have no need to create compounds that defend them. For example, in organic versus nonorganic artichokes, the level of [a] Q40 could vary up to 40 times."
Society's craving for sweetness has also hindered antidisease-crusading antioxidants, which, according to Dr. Tan, often lie in sharp flavours. "In the past 50 years, botanists have bred out bitterness in plants but they've removed a lot of beneficial compounds." The English laboratory where he works will soon be comparing new and old varieties of wild strawberries and apples to determine better their phytochemical differences.
Would our ancestors be shocked by our current food supply? Probably. As for the effects modern processing has on our food, that's a whole other column.