Vegetables are losing their nutrients. Can the decline be reversed?

According to research, calcium in green beans has dropped and vitamin A levels in asparagus dropped by almost half in the 20th century.Photo: Oscar Wong/Getty Images

In 2004, Donald Davis and fellow scientists at the University of Texas made a startling discovery: 43 foods, mostly vegetables, showed a significant decrease in nutrients between the middle and end of the 20th century.

According to that research, the calcium in green beans dropped from 65 to 37mg. Vitamin A levels dropped by almost half in asparagus. Broccoli stems had less iron.

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Nutrient loss has continued since that study. More recent research has documented the decline in nutritional value of some staple crops due to the rise of atmospheric carbon dioxide (CO).₂) levels; A 2018 study that tested rice found that CO₂ reduced levels of its protein, iron and zinc content.

Although the climate crisis has only increased concern about the nutritional value of crops, which has encouraged the development of a process known as bio-fortification as a strategy to replenish lost nutrients or those that foods did not have in the first place.

Biofortification encompasses multiple technologies. One involves genetically modifying a crop to increase its nutritional content, allowing for the rapid introduction of new traits. Other agronomic biofortification uses nutrient-rich fertilizers or soil amendments to target specific minerals in plants. Finally, selective plant breeding can produce new varieties, although it may take ten years or more to yield a single variety.

Biofortification is an alternative to fortification, which has been part of the US industrial food system since the 1920s, when the nation began fortifying table salt with iodine to reduce conditions related to mineral deficiency, such as goiter. Biofortification puts nutrients directly into the seed, unlike fortification, which puts nutrients into food when it is grown. On the global stage, international stakeholders such as the World Health Organization (WHO) and the Consultative Group on International Agricultural Research (CGIAR) consider the development of nutrient biolocking crops to be one of their main goals in achieving food security.

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Prateek Uniyal, head of the program at the International Food Policy Research Institute (IFPRI), explained that “due to climate change, there is a 30-40% reduction in iron and zinc due to excessive rain, cold and physical damage” .

HarvestPlus is an organization under IFPRI, and provides global leadership in biofortification evidence and technology. He is currently working with governments in more than 30 countries, and his biofortified varieties have been planted by more than 10 million farmers around the world, mainly in developing countries. By 2030, the organization estimates, 1 billion people will benefit from biodegradable foods. “We’re about 20 years into a 40-year program,” said Jenny Walton, head of commercialization and scaling at HarvestPlus. “We are trying to revolutionize staple food systems.”

Although malnutrition shows the urgent need to increase the nutrient density of crops worldwide, Benjamin Cohen, professor of environmental studies at Lafayette College, points to biofortification as a Band-Aid, rather than a solution to the problem.

“My concern is that funders, based on policy makers, are choosing to invest in biofortification instead of supporting sustainable smallholder farming models that may be more efficient and resilient than systems large scale,” Cohen said. “Promoting biofortification suggests solving a problem that would not exist if not for large-scale, capital-intensive agriculture. Those same agricultural processes would probably only be more entwined with bio-consolidation.”

HarvestPlus sees plant breeding as the most sustainable way to biofortify; it depends on existing plant genes. The organization works exclusively with staple crops and is developing them to contain higher amounts of vitamin A, iron and zinc, three micronutrients identified by the WHO as the most deficient in diets worldwide . That approach means that in places like Pakistan, where diets are heavy on wheat, which confirms that grains can change at the population level. HarvestPlus has already released 400 staple crop varieties; none of them are patented.

But there is another concern that nutrients are being lost on a wider scale than biofortification can replace.

Davis, who led the original University of Texas study that showed a decline in nutrient value in crops, said: “A limitation of biofortification is that it targets one or maybe two nutrients per plant, but decay affects nutrient on many nutrients at the same time.”

And then there is the barrier of accessibility. Walton noted that there is not yet a consistent supply of biofortified seeds. HarvestPlus also plans to make its biofortified seeds cost less than conventional seeds. But those lowered costs are the result of government subsidies. For example, India has partnered with HarvestPlus to provide biofortified food to children, in a country with a high rate of malnutrition that stunts youth growth.

The government’s partnership model can pay off in low- and middle-income nations where malnutrition is common and businesses work directly with the smallholder farmers who are growing biofortified varieties, rather than on an industrial scale because the seed supply cannot yet to be achieved.

Cohen pointed out that while the need may be greatest in less industrialized countries, such countries may have fewer mechanisms to oppose policies initiated by countries with better resources. They may also have fewer regulations on genetically modified, biodegraded crops, such as the controversial golden rice, which has been modified to produce beta-carotene and, as a result, vitamin A. Although golden rice was bred to help with vitamin deficiencies To put it mildly, Cohen writes that this strategy takes “technical fixes to problems that could be tackled in ways that are less dependent on mono-crop environments”. Basically, if we plant a diversified crop that has the vitamins that are lacking in a certain population, the same nutritional result could be achieved.

He said: “Powerful nations have dictated the shape of food systems in other countries, leaving them in a state of greater malnutrition, and now because those countries do not have enough power to coordinate their policies on a global market, the same powerful nations can. go back now and intervene in their food systems.”

In addition, the industrial agricultural system also favors chemical fortification, said Peter Kelly, CEO of Grow Further, a philanthropic organization that invests in early-stage scalable agricultural innovations in developing countries. He said there is “not much interest in biofortification for the US domestic market. Several US food companies are supporting international work to improve nutrition. But it is not really necessary in our present [US] food system as it can be done with chemical fortification.”

Kelly suggests combining biofortification with other changes to seeds – perhaps breeding them to be more drought resistant – to further encourage stakeholders to invest in crops better suited to local growing conditions.

“All of our work involves adapting to climate change in some way,” Kelly said. “Carbon dioxide levels can affect nutrient levels in plants; we have to do this plant breeding just to keep up. Improving fruit, vegetables and beans is one approach, but if that’s the only approach from a public policy perspective, it’s kind of idealistic.”