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Has our food’s nutritional value evolved over time?

A person holds a variety of freshly harvested vegetables, including carrots, beets, onions and peppers.
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Une personne tient une variété de légumes fraîchement récoltés, y compris des carottes, des betteraves, des oignons et des poivrons.
Has our food’s nutritional value evolved over time?

The food system rapidly industrialized at the start of the 1960s. This period, dubbed the Green Revolution, is characterized by an improvement in irrigation techniques, mechanization, the use of mineral-based fertilizer, and pesticides. The Revolution was also driven by the development of more productive varieties. All these innovations triggered a sharp increase in productivity, and profoundly altered the agricultural world.1 Of course, they’ve also led to incalculable environmental impacts, but it’s now possible to feed more people by cultivating the same surface areas.

However, have these agricultural innovations had an impact on the nutritional qualities of harvested produce? It’s not uncommon to read or hear the following claim: “fruit and vegetables were more nutritious before.”

So what’s the real story? What are the factors that might explain these changes, and what are the nuances we need to consider for a full understanding of the situation?

Does an apple a day really keep the doctor away?

According to a number of studies, certain products currently consumed have lost a significant percentage of their nutritional value in comparison with those grown before.

National Geographic, for example, tells us: “Depuis 70 ans, notre système agricole de plus en plus intensif entraîne une diminution importante des nutriments présents dans nos assiettes.”2

So, have we reached the point of two apples a day to keep the doctor away?

Let’s explore the three main causes that might account for this nutritional decline:

Bigger, but less nutritious harvests

One of the major innovations involved is the development of new, more productive varieties. But there seems to have been a trade-off, with some studies talking about a significant drop in the nutritional value of certain crops.3

A study dealing with the dilution effect demonstrates “inverse relations between crop yield and mineral and protein concentrations.”4 It tells us that the more productive varieties have less mineral concentration, whence the expression dilution effect.

Hybridization

Hybridization consists in creating new plant varieties by forced cross-breeding. Whereas the processes leading to OMGs require the addition of genes (in the laboratory), hybridization strives to accentuate natural traits already present in plants – by way of forced pollination, for example.

We can also think of varieties that are more resistant to disease, or of sweeter or more colorful fruit, or of fruit that withstands transportation and storage. Examples are infinite, but the logic is the same: produce more, and reduce losses to maximize the industry all the way from field to plate, including harvesting and storage.

Soil degradation

With intensive agriculture comes a modification in soil composition and structure.

Mechanical plowing and the spreading of synthetic fertilizers and pesticides are the first elements to be singled out. These have led to a leaching of nutrients and a decline in soil biodiversity. And impoverished soil reduces the ability of plants to absorb certain nutrients.5

On top of this, changes in the composition of the atmosphere also seem to affect plants.

Concentration of CO2 in the air

Another alarming signal comes from a study indicating a decline in the zinc, iron and protein content of certain legume and cereal crops.6

That falloff would seem to be connected to the increase in CO2 levels. We’re talking here about plants using photosynthesis, like the rice, wheat and soybeans that entire populations depend on (C3 carbon fixation).

Studies to take with a grain of salt

Although a wealth of studies and articles point to the fact that the nutritional value of our food has changed, the truth seems to be much more nuanced.11 These studies are criticized for sometimes being misinterpreted or exaggerated, and for focusing only on certain minerals or vitamins. Moreover, comparing the nutritional values of two different periods may be difficult, because methods of analysis have changed enormously.7 We should mention that naturally there’s significant variation among varieties and depending on the origin of the products under analysis (among apples, for example).8-9 Also, the nutritional value of food may vary greatly according to freshness and conservation.10

The fact remains that we’ve completely upended agriculture in the name of growth, and that despite the lack of consensus, the signs are alarming.

Scientific rigor and the precautionary principle therefore invite us to be more vigilant, while continuing with our studies. Despite persistent doubts, eating sufficient quantities of fruit and vegetables is still a beneficial habit for health. And the impacts on ecosystems are very real.

As the population continues to increase, which innovations will be the next ones needed to make sure that everyone is fed?

Sources

  1. La révolution verte et la naissance du système alimentaire industrialisé (The Green Revolution and the Birth of the Industrialized Food System) - Les Greniers d'Abondance (resiliencealimentaire.org)
  2. Fruits and vegetables are less nutritious than they used to be | National Geographic
  3. Thomas D. A Study on the Mineral Depletion of the Foods Available to us as a Nation over the Period 1940 to 1991. Nutrition and Health. 2003;17(2):85-115. doi:10.1177/026010600301700201
  4. Davis, D. R. (2009). Declining Fruit and Vegetable Nutrient Composition: What Is the Evidence?. HortScience horts, 44(1), 15-19. Retrieved May 9, 2024, from https://doi.org/10.21273/HORTSCI.44.1.15
    a. Declining Fruit and Vegetable Nutrient Composition: What Is the Evidence? in: HortScience Volume 44 Issue 1 (2009) (ashs.org)
  5. Montgomery DR, Biklé A, Archuleta R, Brown P, Jordan J. Soil health and nutrient density: preliminary comparison of regenerative and conventional farming. PeerJ. 2022 Jan 27;10:e12848. doi: 10.7717/peerj.12848. PMID: 35127297; PMCID: PMC8801175.
    a. Soil health and nutrient density: preliminary comparison of regenerative and conventional farming - PMC (nih.gov)
  6. Myers, S., Zanobetti, A., Kloog, I. et al. Increasing CO2 threatens human nutrition. Nature 510, 139–142 (2014). https://doi.org/10.1038/nature13179
    a. Increasing CO2 threatens human nutrition | Nature
  7. Robin J. Marles, Mineral nutrient composition of vegetables, fruits and grains: The context of reports of apparent historical declines, Journal of Food Composition and Analysis, Volume 56, 2017, Pages 93-103, ISSN 0889-1575, https://doi.org/10.1016/j.jfca.2016.11.012.
    a. Mineral nutrient composition of vegetables, fruits and grains: The context of reports of apparent historical declines - ScienceDirect
  8. Bertin, N., Génard,M. Tomato quality as influenced by preharvest factors, Scientia Horticulturae, Volume 233, 2018, Pages 264-276, ISSN 0304-4238, https://doi.org/10.1016/j.scienta.2018.01.056.
    a. Tomato quality as influenced by preharvest factors - ScienceDirect
  9. Les fruits et légumes ne sont pas moins nutritifs qu'il y a quelques décennies, dit un nutritonniste Les fruits et légumes ne sont pas moins nutritifs qu'il y a quelques décennies, dit un nutritonniste (Fruit and vegetables are not less nutritional than a few decades ago, says a nutritionist) (radio-canada.ca)
  10. Linshan Li, Ronald B. Pegg, Ronald R. Eitenmiller, Ji-Yeon Chun, Adrian L. Kerrihard, Selected nutrient analyses of fresh, fresh-stored, and frozen fruits and vegetables, Journal of Food Composition and Analysis, Volume 59, 2017, Pages 8-17, ISSN 0889-1575, https://doi.org/10.1016/j.jfca.2017.02.002.
  11. Une pomme de 1950 n’équivaut pas à 100 pommes d’aujourd’hui (A 1950 apple does not equal 100 of today’s) (nutritionnisteurbain.ca)

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2 Comment(s)
George's picture
George

Food production has increased thanks to modern agriculture, but the possible decline in nutritional value is worrisome. Prioritizing both quantity and quality in agricultural Wordle Unlimited techniques should be our main goal.

nablelung's picture
nablelung

With global food demand rising, future innovations must consider both productivity and nutritional resilience to sustainably feed growing geometry dash populations.

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Anonymous's picture