WHAT'S DOWN, DOC?: Although fruits and vegetables are still our best source of nutrients, those grown decades ago were much richer in vitamins and minerals than the varieties most of us get today. The main culprit in this disturbing nutritional trend is soil depletion.
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Dear EarthTalk: What’s the nutritional difference between the carrot I ate in 1970 and one I eat today? I’ve heard that that there’s very little nutrition left. Is that true?—Esther G., Newark, N.J.
It would be overkill to say that the carrot you eat today has very little nutrition in it—especially compared to some of the other less healthy foods you likely also eat—but it is true that fruits and vegetables grown decades ago were much richer in vitamins and minerals than the varieties most of us get today. The main culprit in this disturbing nutritional trend is soil depletion: Modern intensive agricultural methods have stripped increasing amounts of nutrients from the soil in which the food we eat grows. Sadly, each successive generation of fast-growing, pest-resistant carrot is truly less good for you than the one before.
A landmark study on the topic by Donald Davis and his team of researchers from the University of Texas (UT) at Austin’s Department of Chemistry and Biochemistry was published in December 2004 in the Journal of the American College of Nutrition. They studied U.S. Department of Agriculture nutritional data from both 1950 and 1999 for 43 different vegetables and fruits, finding “reliable declines” in the amount of protein, calcium, phosphorus, iron, riboflavin (vitamin B2) and vitamin C over the past half century. Davis and his colleagues chalk up this declining nutritional content to the preponderance of agricultural practices designed to improve traits (size, growth rate, pest resistance) other than nutrition.
“Efforts to breed new varieties of crops that provide greater yield, pest resistance and climate adaptability have allowed crops to grow bigger and more rapidly,” reported Davis, “but their ability to manufacture or uptake nutrients has not kept pace with their rapid growth.” There have likely been declines in other nutrients, too, he said, such as magnesium, zinc and vitamins B-6 and E, but they were not studied in 1950 and more research is needed to find out how much less we are getting of these key vitamins and minerals.
The Organic Consumers Association cites several other studies with similar findings: A Kushi Institute analysis of nutrient data from 1975 to 1997 found that average calcium levels in 12 fresh vegetables dropped 27 percent; iron levels 37 percent; vitamin A levels 21 percent, and vitamin C levels 30 percent. A similar study of British nutrient data from 1930 to 1980, published in the British Food Journal,found that in 20 vegetables the average calcium content had declined 19 percent; iron 22 percent; and potassium 14 percent. Yet another study concluded that one would have to eat eight oranges today to derive the same amount of Vitamin A as our grandparents would have gotten from one.
What can be done? The key to healthier produce is healthier soil. Alternating fields between growing seasons to give land time to restore would be one important step. Also, foregoing pesticides and fertilizers in favor of organic growing methods is good for the soil, the produce and its consumers. Those who want to get the most nutritious fruits and vegetables should buy regularly from local organic farmers.
UT’s Davis warns that just because fruits and vegetables aren’t as healthy as they used to be doesn’t mean we should avoid them. “Vegetables are extraordinarily rich in nutrients and beneficial phytochemicals,” he reported. “They are still there, and vegetables and fruits are our best sources for these.”
CONTACTS: Journal of the American College of Nutrition, www.jacn.org; Kushi Institute, www.kushiinstitute.org; Organic Consumers Association, www.organicconsumers.org.
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18 Comments
Add CommentThe article blames soil depletion, but Dr. Davis is quoted talking about breeding. Is genetics the real problem? By breeding for traits such as appearance or pest resistance, have we lost genes for nutrition?
Reply | Report Abuse | Link to thisThis article is written not by SciAm but by EarthTalk, a magazine with, shall we say, 'creative' and 'bold' interpretations of science. According to more mainstream interpretations, soil depletion, erosion, and salt accumulation are problems for farmers, but have very little to do with the concentrations of minerals and nothing to do with the concentrations of vitamins in plants.
Reply | Report Abuse | Link to thiswww.soils.wisc.edu/~barak/poster_gallery/minneapolis2000a/
On the other hand, there is solid evidence that farmers are tending to choose sweeter, more attractive, and more productive varieties of crops at the expense of more nutritious ones. (Fortunately, many antioxidants are both attractive and nutritious.) The solution is for consumers to demand more nutritious crops and learn to enjoy more complex flavors. I suspect even EarthTalk readers will stand behind that message.
It's a mix of both really. With the fast growing newer breeds of fruits and veggies, there is less time for the mycorrhizae to trade their minerals for the plants carbs, based on the speed that the plant grows and the roots of the plant now getting deep enough in the ground to reach the majority of the mycorrhizae. And for the vitamins part, too many fruits and veggies are picked before their full ripeness, where most of the vitamins are placed in the fruit/veg near their full ripeness, so if they are pulled prior to being ripe all to be able to arrive at the grocery store at their peak ripeness then they obviously won't have as many vitamins. And now that we have more food being transported from further and further away it just exacerbates the problems.
Reply | Report Abuse | Link to thisAlot of it is explained in Michael Pollan's book In Defense Of Food.
So that's why it is better to buy local and organic, mostly due to picking at the proper time, soil quality/thickness, and root length of the plants.
I picked up information from Standard Process nutritional company that the 'altitude' of the prairies dropped 6 foot since the late 1800's. How does agribusiness plan on replacing 6 feet over several states to replace depleted mineral. Moreover, the article missed one important point: plants rely on soil bacteria, which utilize inorganic minerals making them organic minerals. Hence the reduction of pesticides would help as the pesticides also affect soil bacteria. Nevertheless, 6 feet of soil mineral content is a lot to overcome.
Reply | Report Abuse | Link to thisIt is all about marketing. At one time in the United States small farmers grew most of the fruits and vegetables. They constantly looked for places to sell their output. Old books refer to that as truck farming. They would load their crop on the truck and take it to a warehouse to sell it. The warehouses would sell to other warehouses and then to local grocers. The supply system looked like spaghetti but the food was good.
Reply | Report Abuse | Link to thisChain stores slowly replaced family grocers. They wanted a steady supply at a lower price.
The factory farm replaced the truck farm. A large produce supply house moves the food from the factory farm to the chain store warehouse. From there it goes to the individual store.
To make sure fruit and produce grown at the factory farm remains fresh when it arrives at the store, the factory farm grows varieties with long shelf life. These varieties have less flavor but remain edible longer.
There you have it. Your food had far fewer people handle it. Machines did far more of the work. The food looks far more uniform. It has longer shelf life.
If you want food to taste like it came from a garden tended by hand instead of a factory farm, you will need to pay more for it. It costs money to hire more people to produce the same amount of food.
You can promote organic all you want but the simple fact is that modern industrial farming feeds more per acre than organic farming does. I'm all for organic but only what I grow myself. Carrots and potatos don't do well here but I have a variety of fruit bushes and vines. I also grow plenty of tomatoes and peppers.
Reply | Report Abuse | Link to thiswell put...
Reply | Report Abuse | Link to thisThe crops have been bred for yield, appearance, uniformity (of both size and ripening time), disease resistance, and shipping and keeping qualities in storage. I know of no common food crop that has been bred for nutritional content.
Reply | Report Abuse | Link to thisIt's rather strange, though, that the article doesn't place much if any emphasis on soil mineral depletion. The reason N, P, and K are added as fertilizers is because the crops take them up, they are shipped away, and then must be replaced in the soil in order to grow another crop of the same yield. Plants have been shown to require around twenty essential minerals; humans need more than thirty minerals. Why are only three minerals replaced in the soil? Are the other minerals that have been taken up and shipped away supposed to magically re-appear?
An analogy could be a sweetened drink that had all of the needed nutrients in it, where each time some was drunk the bottle was topped up again with sugar water. The bottle would still appear full, but it would soon have less and less of the other needed nutrients.
Michael Astera
http://soilminerals.com
What ever happened to putting land in fallow? Does acid rain deplete minerals?
Reply | Report Abuse | Link to thisscilo-
Reply | Report Abuse | Link to thisAcid rain, or any rain, can leach minerals out of the soil. Every time a crop is grown and sold off the land takes away minerals. If what is leached out or shipped away is not replaced, well, the obvious thing happens: the soil ends up depleted of minerals.
There is an extremely alteration in vegetables and fruits energy metabolic pathways caused by fertilizers, pesticides, poisonous agrochemicals and aluminium concentrations in the soil , therefore plants will response to this environmental noxious stress by changing their biochemical constituents. Regrettably, the nightmare is just beginning because unavoidably, when we are eating vegetables and fruits, we are also consuming their toxicity !. Hence, its harmfulness effects will alterated our metabolism , giving rise to different health problems and disorders as the Dysmetabolic Syndrome that is increasingly affecting million of people globally.
Reply | Report Abuse | Link to thisSimultaneously, I was reading a book ¨ Plant Physiological Ecology¨ that points out literally a big truth: ¨ For plants there is no alternative but to utilize sunlight and fix carbon and to draw water from soil under a given range of environmental conditions¨ .
So, technologize solutions to this problem , unfortunately is a mere illusion!
This is all good work, but the biggest job continues to be, how do we replace the 95% share of petroleum of inputs that go into the production of food? There, organic food production will be key, but we must also get manual labor to the fields to get anywhere near the harvest and production that we currently get, and we are now largely an urbanized world! Please see my urgent suggestions at www.greenmillennium.eu and please think, comment and react early enough to keep most of our children alive!
Reply | Report Abuse | Link to thisActually, I believe you are mistaken. What you profess is what conventional farming believes. But organic farmers have studies proving otherwise, although there certainly is a period when production is lower as the soil recovers from its overexploitation. Apart from the productivity question, there is also the question of quality, which in this contect seems of critical importance.
Reply | Report Abuse | Link to thisThis reply was written in reply to "bucketsofsquid" comment that conventional agriculture produces more even if of a lower quality.
Reply | Report Abuse | Link to this
Reply | Report Abuse | Link to thisI've gotten so tired of the made for transport, etc vegetables that I'm going to grow my own to get plant ripened ones that taste decent.
Plus I'll be able to afford it. A 10'x10' garden grows about $700 worth of food and once put in takes little work. I think a good business model would be setting up and maintaining food gardens for those who don't want to learn, deal with it.
Amazingly many really good posts on this article. A nice change from most on SA.
In my little home garden which I have for 44 years , I replenish the minerals/nutrients taken out by the crop with stuff called artificial fertilisers and my plants are usually quite healthy.
Reply | Report Abuse | Link to thisI know my Tomatoes are much juicier , and taste much better than the Supermarket ones.
Those are actually tasteless and tough.
I give mine extra Potash to make the taste even better.
A should add that I am a Compost Fanatic and heap it on from my large Corrugated Iron Bin,medium size slotted timber Bin and 5 cylindrical Plastic Bins.
Reply | Report Abuse | Link to thisIt looks lovely crumbly black super nice stuff for the garden.
Interesting article! If you are concerned about the quality of your food and looking for a sustainable way to garden check this out. Aerophonic-soil-less vertical gardening in your own backyard...and you don't need a yard to do it!
Reply | Report Abuse | Link to thishttps://nosoil.towergarden.com/