People can consume enough calories and still fall short on essential vitamins and minerals. That problem, often called hidden hunger, affects populations in wealthy and lower-income countries alike and has prompted scientists to look for ways to make widely eaten crops more nutritious.
A review published in Nature examines how conventional breeding, genetic engineering and newer gene-editing tools could increase the micronutrient content of staple foods while also helping crops withstand drought, flooding, salt and other environmental stresses. The authors argue that no single technology can solve micronutrient deficiencies and that biofortification must complement, rather than replace, dietary diversity, food fortification, supplements and broader improvements in food access.
The article is a review of existing research, not a new human trial. It describes current approaches to biofortification, which means developing crops with higher levels of particular nutrients in the edible portion of the plant.
That differs from conventional food fortification. Fortified flour, for example, receives nutrients during processing. A biofortified crop is bred or engineered to produce or retain more of a nutrient as it grows.
The need is substantial. The authors cite global estimates suggesting that more than half of the world’s population may consume inadequate amounts of several nutrients, including vitamins B2, B9, C and E, along with calcium, iron and iodine.
Those figures describe estimated inadequate intake, not medically confirmed deficiencies in every person counted. Still, they illustrate how common it is for diets to provide sufficient energy without supplying enough micronutrients.
Staple crops are a major focus because foods such as rice, wheat and corn provide a large share of daily calories worldwide. Increasing the nutrient content of crops people already eat could help improve intake without requiring families to adopt entirely new diets or gain access to unfamiliar foods.
The review discusses more than 400 nutrient-enriched crop varieties developed through conventional breeding since biofortification became a larger research priority in the 1990s. These include wheat, corn and beans bred to contain more zinc, iron or provitamin A.
Conventional breeding works by identifying plants with desirable traits and crossing them over multiple generations. It is widely accepted and does not require introducing genetic material from another species, but it is limited to traits already present in plants that can be crossed. Developing a market-ready variety may take eight to 15 years.
Mutation breeding creates additional genetic variation by exposing seeds or other plant material to radiation or chemicals. Breeders then screen the resulting plants for useful traits.
This method has been used to develop iron-enriched rice and wheat containing more provitamin A. It can create new traits more quickly than waiting for them to emerge naturally, but the mutations are random, so researchers must search through many plants to find the desired result.
Genetic engineering allows scientists to make more specific changes, including introducing genetic instructions that a crop does not already possess.
Golden Rice is the best-known example. Scientists engineered the rice to produce beta carotene, which the body can convert into vitamin A. The grain’s yellow color comes from the added provitamin A.
Golden Rice demonstrates that genetic engineering can change the nutritional composition of a staple crop. Its history also shows that scientific development is only one part of whether a biofortified food improves public health.
A crop must pass regulatory review, perform well for farmers, reach communities that need it, remain affordable and be accepted by consumers. Researchers must also establish that the added nutrients remain available after storage, processing and cooking and that eating the crop meaningfully improves nutrient status or health.
Higher nutrient content alone does not prove that a crop will prevent deficiency or disease.
The review identifies CRISPR and other gene-editing techniques as especially promising because they can modify specific parts of a plant’s genome. Unlike some earlier forms of genetic engineering, gene editing does not always involve adding genetic material from another species.
Researchers have already used gene editing to develop experimental crops with increased levels of nutrients, including rice with more iron and zinc. The authors estimate that new varieties could be developed within about two to six years, although regulatory review, testing and adoption can extend the process.
Public policy toward gene-edited crops differs by country. Some governments regulate certain gene-edited plants similarly to conventionally bred crops when the genetic change could have occurred naturally. Others treat them under rules developed for genetically modified organisms.
The authors argue that more flexible regulation could speed the development of nutrient-enriched crops. That does not eliminate the need to evaluate safety, environmental effects, farming performance and nutritional benefit.
The review also connects crop nutrition with climate resilience. Vitamins do not benefit humans alone. Plants use many of the same compounds to regulate growth and protect themselves from environmental stress.
Research has found, for example, that thiamine, or vitamin B1, can support plant responses to drought. Other B vitamins, along with vitamins C and E, help plants respond to oxidative stress caused by drought, salt, flooding and other difficult conditions.
That raises the possibility that breeding crops for higher vitamin content could offer two benefits: more nutrient-dense food for people and plants that are better able to cope with environmental stress.
The relationship is unlikely to be simple. Increasing one nutrient can affect plant growth, yield, taste, storage life or the availability of other nutrients. A variety that works well under laboratory conditions may not perform the same way in farmers’ fields or across different climates.
Processing and cooking can also change the final nutrient content. A crop may contain more of a vitamin at harvest but lose part of it before reaching the plate.
The authors therefore do not present conventional breeding, genetic engineering or CRISPR as a complete solution.
“This is a great opportunity to accelerate the development of biofortified crops and effectively combat hidden hunger,” co-author Mustafa Bulut said of changing regulations for newer genomic techniques in Europe.
Even so, reducing micronutrient deficiencies requires more than changing plant genetics. People also need access to varied, affordable diets, health care, nutrition education and, when appropriate, fortified foods or supplements.
Biofortification may be most useful when it works alongside those approaches. Improving the foods people already rely on could help close some nutrient gaps, but the benefits will depend on whether the crops succeed outside the laboratory and reach the communities they are intended to serve.
The work received support from the Francqui Foundation, the European Union’s Horizon Europe program, Taiwan’s Ministry of Education, the Carlsberg Foundation and the Novo Nordisk Foundation. One author is an emeritus fellow of the International Food Policy Research Institute.