I see that a study of 43 different crops found that many of today's fruits and vegetables do not have the same nutritional content as 50 years ago. For those of us who grow our own, the flavor gap between supermarket produce and that from our garden seems to have widened, especially when comparing heirloom varieties to the latest "improved" hybrids. However, the decline in nutrient content is also something worth noting.
Researchers led by Dr. Donald Davis, a bio-chemistry professor at the University of Texas at Austin, compared chemical analyses by the USDA from 1950 and 1999 to see how nutrient contents may have changed. They found that average levels of protein, calcium, phosphorus, iron, riboflavin, and vitamin C had all dropped anywhere from 6% (for protein) to 38% (riboflavin).
There may well be other drops as well, but the comparisons were limited to the nutrients reported in 1950, so the researchers could not gauge changes in such things as magnesium, zinc, vitamins B & E, fiber content, nor important phytochemicals discovered more recently. My guess is that these would also be reduced.
The researchers feel that the most likely explanation for the decline in nutrients was changes in varieties stemming from intensive efforts to breed new varieties for greater yields, increased resistance to pests, or adaptability to different climates - with pursuit of higher yields being dominant. Other contributing factors might be yield-enhancing strategies such as more irrigation and heavier fertilizing. This has all led to modern crops growing larger and faster, but apparently with less nutrient value - an unintended consequence.
A related thought is my memory of a USDA research scientist telling me that his organization had only just recently hired a specialist to study crop flavors. I think his exact words were, "It has never been much of an issue to us." This was surprising to me, as I had always assumed that the flavor of a food item would be a routine and important part of selecting new varieties.
Now I'm obviously biased on this topic, but I'd be willing to bet that the decimation of biological microorganisms and depletion of trace minerals in conventional crop soils also have a lot to do with both the declines in flavor and nutrient value. I doubt that vegetables that are fed incomplete NPK fertilizer in lifeless soil have as much chance of ending up tasty and nutritious.
Yes, I know - I'm being preachy about big-picture issues again, and why bother? Well, I could be wrong, but I think the mindset of growing only for appearance and bigger yields can be changed. If horticultural researchers really put their minds to it and began regarding flavors as being more than a side issue, I'm sure they could develop high-yielding varieties that taste better and pack more nutrients. Of course, first they must want to.
I suspect that superior flavor and superior nutrients are linked, so informed consumers can push the researchers by simply choosing the tastiest produce available. As a model, I would point to the success of the Fuji and Gala apples in knocking down sales of the old Red Delicious variety, a tragic example of an originally-tasty fruit ruined by "improvements." Unfortunately, I see that the Fuji is now being made more red, and, at least to my taste buds, is becoming less flavorful. (Sigh)
Hey, pay a little more for organically-grown stuff and give those misshapen yellow tomatoes a try next time - it could benefit all of us down the road some day!
President, BioOrganics, Inc.