Greta Canelli

Malnutrition continues to threaten the developing world. This is partly the result of a lack of access to a differentiated diet. Agricultural biotechnology can generate crops that are biofortified with vitamins and minerals. Biofortified crops can be one of the solutions to alleviate “hidden hunger”.

The burden of malnutrition

Micronutrient malnutrition is a global health problem, especially in low- and middle-income countries. One third of the world’s population, about 2 billion people, are deficient for one or more of the key micronutrients iron, zinc and vitamin A. Although most micronutrients are required only in traces for human nutrition, they are essential due to their involvement in vital metabolic processes in the human body.

Most of the “food insecure” people are located in sub-Saharan Africa and Southeast Asia. Although the number extreme poor people (living on less than $1.25 a day) has progressively decreased over the last 25 years, the combination of rapid population growth and the precarious livelihoods of many of the rural poor has undermined economic improvements. Often, rural farmers in developing countries struggle to recover from environmental shocks such as drought, excessive temperatures, or flooding. Climate change will make these occasional shocks even more frequent. In addition, the world’s population is predicted to increase to 9–10 billion people by 2050, with the vast majority of that increase taking place in developing countries. To keep up with the expected growing population, agricultural productivity must double by 2050. In 2015, the United Nations set out a list of Sustainable Development Goals which were intended to address, among others, global poverty and hunger. One of the aim is that the most vulnerable people would be lifted out of extreme poverty and could have the means to improve their general nutritional status by diversifying their diets with the wide range of micronutrients found in assorted fruits and vegetables.

There are many available interventions to address micronutrient malnutrition: food diversification, biofortification of staple foods, fortification of foods, and supplements.

Maize, wheat and rice are broadly cultivated, and because of their wide availability and affordability, they are consumed in large quantities and represent staples within diets around the world. Unfortunately, these cereals are low in essential micronutrients, resulting in high prevalence of micronutrient malnutrition among large populations, particularly resource-poor consumers in South Asia and sub-Saharan Africa.

What is biofortification?

Biofortification is the breeding of enhanced concentrations of bioavailable nutrients in staple food crops. The micronutrient content in edible parts of staple crops can be enhanced by enhancing phyto-availability of minerals in soil for plant uptake, improving transport of absorbed minerals to comestible plant parts, decreasing the concentrations of anti-nutrients, or breeding for increased/decreased enzymatic activity to help accumulation of wanted micronutrient precursors. Recombinant DNA technology, such as genetic engineering, can result in crops with new traits that cannot be achieved by conventional breeding practices. Novel traits can be introduced into a crop through the manipulation of its genetic material.

In addition, storage and processing technologies offer opportunities to enhance the retention or bioavailability of micronutrients in food obtained from biofortified crops. Several efficacy studies have shown that biofortification of staple crops can successfully contribute to improving micronutrient malnutrition or “hidden hunger” among susceptible populations. Biofortified crops are already available and contributing to strategies to alleviate micronutrient deficiencies in about a dozen countries of Africa, Asia and Latin America.

A well-known example of a genetically modified food crop that produces a biofortified product is Golden Rice. Golden Rice expresses β-carotene, a precursor of vitamin A. It is intended to produce a fortified food to be grown and consumed in areas with a shortage of dietary vitamin A, a deficiency which each year is estimated to kill 670,000 children under the age of 5 and cause an additional 500,000 cases of irreversible childhood blindness. Rice is a staple food crop for over half of the world’s population, providing 30–72% of the energy intake for people in Asian countries, and becoming an effective crop for targeting vitamin deficiencies. In this case, the genes introduced into the rice plant come from another plant (daffodil) and from a specific bacterium. For this reason, they are called transgenic plants. Much research is being undertaken in the field of crop science and soon crops with improved agronomic traits, such as drought tolerance, higher yield, pest resistance, and improved nutritional content, will be realized in the near future.

Fig. 1. Crop development framework. Source: HarvestPlus. (Bouis and Saltzman 2017)

Advantages of biofortification

Among available interventions to address micronutrient malnutrition – food diversification, biofortification of staple foods, fortification of foods, and supplements – biofortification has many advantages.

Biofortification of crops through genetic engineering is described by many to be more cost-effective than other supplementation strategies. Biofortified crops can be adapted through pre-existing seed and crop distribution channels and can be maintained by the farmers themselves. Supplementation of diets with vitamins and minerals in the form of pills or powders requires connecting reliably with a target population who may reside in a remote area. Supplementation also requires large investments and monitoring on a regular basis. Increasing micronutrients through agronomic bioavailability, on the other hand, through the application of fertilizers on soil can also largely be successful, but depends on the mineral and crop species, cannot target specific edible plant organs, and cannot be an approach to provide vitamins or other bioactive compounds that requires synthesis by the plant. Similarly, conventional breeding for mineral dense varieties can be very time consuming and largely depends on the gene pool that pre-exists in a crop species. Genetic engineering is often the only feasible option to increase micronutrient availability in a crop that does not produce that particular micronutrient, as is the case of β-carotene in rice grain.

Challenges for the implementation of biofortification

There are some cautions to produce biofortified crops, including regulatory restrictions, which could delay the approval of the crop. In addition, technical-scientific challenges are present: the metabolic engineering of a biochemical pathway itself can be difficult to manage. The production of a desired compound may need to be increased, while non-desirable or competitive end products may require downregulating, and, in certain instances, entirely new metabolic pathways must be synthesized in a plant that does not have the ability to accumulate that micronutrient.

Public perception and international policy will influence biotech crop regulation. Under today’s regulatory environment, GM crops must undergo rigorous risk assessment, which centres on detailed molecular characterization of the crop, assessment of toxicity and/or allergenicity, and nutritional content. In Europe, this process has become hindered by the imposition of the precautionary principle guidelines of regulation, which takes the position that GM crops should not be easily made available because they cannot be inherently proven to be safe. GM crop approval process has been suspended across the EU, thus preventing the development of nutritionally enhanced crops advancing for philanthropic purposes.

Conclusions

There is potential for the use of biofortified crops to alleviate “hidden hunger”. However, some aspects must be considered for its effective application in the future.

Attention should now move to an action-oriented agenda for scaling biofortification to advance nutrition globally. To reach one billion people by 2030, there are three crucial challenges: 1) mainstreaming biofortified traits into public plant breeding programs; 2) building consumer demand; and 3) integrating biofortification into public and private policies, programs, and investments. While many building blocks are in place, institutional leadership is needed to continue to drive towards this ambitious goal.

References

Bouis HE, Saltzman A. 2017. Improving nutrition through biofortification: A review of evidence from HarvestPlus, 2003 through 2016. Global Food Security 12: 49–58.

Hefferon KL. 2016. Can Biofortified Crops Help Attain Food Security? Current Molecular Biology Reports 2: 180–185.