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- cross-posted to:
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In 2004, Donald Davis and fellow scientists at the University of Texas made an alarming discovery: 43 foods, mostly vegetables, showed a marked decrease in nutrients between the mid and late 20th century.
According to that research, the calcium in green beans dropped from 65 to 37mg. Vitamin A levels plummeted by almost half in asparagus. Broccoli stalks had less iron.
Nutrient loss has continued since that study. More recent research has documented the declining nutrient value in some staple crops due to rising atmospheric carbon dioxide (CO2) levels; a 2018 study that tested rice found that higher CO2 levels reduced its protein, iron and zinc content.
While the climate crisis has only accelerated concerns about crops’ nutritional value, prompting the emergence of a process called biofortification as a strategy to replenish lost nutrients or those that foods never had in the first place.
There are many things that are unsupported in this article
First off, the laboratory methodology changed for testing food. Modern testing techniques much more accurate than the ones in the 50’s and 70’s. They did not run the older methodologies on modern food. So basically the entire premise is comparing apples to oranges. We don’t know if the changes are due to reality or procedure changes.
The second study on rice had me smiling. From somebody who knows nothing about breeding cereal grain it would seem to be a slam dunk, however reality is more complicated. All cereal breeders struggle with the tradeoff between maximizing yield and lodging resistance. Lodging is when the stalk falls over. When it falls over major yield losses can occur (50%+ depending on the stage). It also causes major difficulties with harvesting on equipment and time. Extra CO2 increases plant size and kernal size. A taller plant with a heavier seed head that a slight breeze will knock over. Breeders will select genetically smaller kernals and smaler stature plants to compensate for increasing CO2. This is the major reason that all hybrid wheat attempts have failed. It makes a huge plant that falls over.
Some basics on nutritional density of vegetables.
Fruit size: in general the larger the fruit lower the nutritional density. The plant only has so much it can create or pull from the soil.
Nutrient density is affected by position on the plant where it is grown. Earlier set fruit tend to have higher nutritional density than later set fruit. You can look up more on this on source/sink studies.
Nutrient availability: plants that are slightly nutritionally deficient will produce smaller fruits/seeds. The smaller size will make the fruit more nutrient dense.
The weather is the single largest determining factor. When a plant is happy with ideal conditions the nutrient density is lower. When the plant is stressed and grows more slowly, it produces less yield with higher density food.
Genetics: Sometimes plant breeders select for higher nutritional density like watermelons. Sometimes they select for lower density like strawberries. It all depends on the market requirements.
Thanks for sharing these details.
Noob question: if I eat a huge apple or a small apple, but eat them full, wouldn’t I effectively get same amount of nutrients?
You would get similar amounts of total nutrients however, you’d eat more carbohydrates. The larger apple has less nutrient density.
Every discussion on food production is like this. Nowhere on the internet have I seen more people confidently spouting absolute nonsense as if it were expert testimony.
To be fair:
I have seen lot of nonsense spouted by the “experts.” PhD levels who are making bad assumptions outside of their field of expertise. I would say only about 1 in 10 papers I read is worth the time to download it.
It’s an ongoing issue with the high level of specialization in the sciences, especially in academia. Any topic which covers multiple disciplines turns into a clusterfuck.
Yes, it’s shocking what gets published nowadays.
But that’s the problem. Capitalism should never have been allowed to effect what a tomato or apple looked like vs the nutritional value it had. And in some (many?) cases that’s what happened.
Market requirements are not necessarily driven by capitalism.
Throughout history, needs of the culture determine the plant breeding efforts. Often flavor and nutrition have been traded for yield and storage.
For example the absolute worst watermelon I ever ate was in Uzbekistan. The soviet’s created a long-storage melon that lasts up to 10 months. It’s was about as bad as eating cardboard.
At a fundamental level the “need” for a long-storage watermelon developes out of capitalism, not a populace’s needs.
No, that’s not correct. The need is for food.