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(photo source: Giphy) when you look at rows of brightly colored fruits and vegetables in the supermarket, you may not realize that the nutrient content of these crops has been declining over the past 70 years.

There is growing evidence from a number of scientific studies that many fruits, vegetables and grains grown today contain less protein, calcium, phosphorus, iron, vitamin B2 and vitamin C than they did decades ago.

Image source: giphy2004 published an article on fruit and vegetable nutrition in the Journal of the American Nutrition Society (Journal of the American College of Nutrition) in December. Using nutritional data released by the U.S. Department of Agriculture in 1950 and 1999, researchers at the University of Texas at Austin noticed changes in 13 nutrients in 43 different fruits and vegetables, such as asparagus and beans to strawberries and watermelons.

Compared with the past, the protein, calcium, phosphorus, iron, vitamin B2 and ascorbic acid of today's fruits and vegetables have all declined, and the median comparison shows that the decline is large or small, such as a 6% drop in protein and a 38% drop in vitamin B2, the biggest drop.

In particular, the calcium content in broccoli, kale and mustard decreased most significantly, while the iron content in beet, cucumber and radish decreased significantly, and the vitamin C in asparagus, kale, mustard and radish decreased significantly.

Further research since then supports the view that nutrients in fruits and vegetables are less than in the past. A study published in January 2022 in the journal Foods found that while most vegetables grown in Australia had relatively similar iron levels between 1980 and 2010, iron levels in some vegetables declined significantly.

The iron content of sweet corn, red potatoes, cauliflower, mung beans, green beans and chickpeas decreased by 30% to 50%. Of course, some fruits and vegetables have improved, such as Haas avocado, mushrooms and sugar beets.

Not only fruits and vegetables, but also grains, the largest source of carbon and water for our bodies, have also seen a significant decline in their nutritional content. A study published in Scientific Reports in 2020 found that from 1955 to 2016, the protein content of wheat decreased by 23%, as did manganese, iron, zinc and magnesium.

All kinds of studies mean that our grandparents are eating healthier than we are now.

And nutrients are not only associated with health, but also with flavor. For example, nutritionally rich tomatoes have sweetness, slight acidity and aromatic release, and the six major nutrients are richer than tomatoes with only acidity or lack of aroma. In addition, vegetables also show that delicious vegetables have more carbohydrates than "tasteless" vegetables. Therefore, it makes sense that the more nutritious fruits and vegetables are, the more delicious they are.

Photo Source: giphy, why are fruits and vegetables worse in terms of nutrition and flavor than they used to be?

The most important point is that modern farming patterns lead to it. The author of the paper in the first study introduced earlier wrote his own conjecture in the discussion that modern industry pays more attention to yield, farmers are paid according to the weight of crops, and increasing yield per unit area means higher planting density. as a result, the nutrients of fruits and vegetables are diluted.

In addition, the decrease in the content of fungi in the soil is also a reason. The growth of wheat, corn, rice, soybeans, potatoes, bananas, yams and flax are all related to key fungi that improve the ability of plants to obtain nutrients and water from the soil. The reduction of fungi is directly related to high-yield tillage, so it is essentially related to farming patterns.

Finally, the increase of greenhouse gas content also has something to do with it. All plants have a photosynthetic pathway in which they absorb carbon dioxide from the atmosphere, decompose it, and then use it to grow. However, when crops, including wheat, rice, barley and potatoes, are exposed to higher levels of carbon dioxide, they produce more carbon-based compounds, resulting in higher carbohydrate levels. This will lead to an imbalance and reduce the amount of micronutrients absorbed from the soil.

Experiments described in the 2018 issue of Science Progress confirmed that after exposure to higher levels of carbon dioxide, the concentrations of protein, iron, zinc and several B vitamins in 18 kinds of rice decreased.

Of course, there is no need to worry too much about the reduction of nutritional content, but for the reduction of individual nutritional content of individual fruits and vegetables, if you lose a little bit of nutrition, you can eat more.

Image source: giphy ends with a nutrition expert's point of view:

"it is not wise to blindly complain about the quality of food in the market. Because it is difficult for us to change the environment, we can only change our choices. We can learn to accept the sour, astringent and bitter taste of natural fruits and vegetables, put up with their less glamorous appearance, accept the natural changes that blacken after cutting, accept wormed fruits and vegetables, and accept defective and spotted peels. If they refuse to accept all this, they always ask that the sweetest, the sweetest, the biggest, the most beautiful, no worms, no defects, and that the food is particularly natural and has a high nutritional value, then it is a bit like Ye Gong. "

Reference:

Https://pubmed.ncbi.nlm.nih.gov/ 15637215/

Https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8750575/

Https://www.nature.com/articles/s41598-020-78504-x#Tab3

This article is from the official Wechat account: bring Science Home (ID:steamforkids), author: everything.

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