This study followed the guidelines for systematic reviews as recommended by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines (PRISMA; Moher et al., 2009; Vrabel, 2015). Five databases (Web of Science, Science Direct, PubMed Central, Abstracts/ProQuest and Google Scholar) were used to identify studies published between 01/01/2012 and 31/01/2025, focusing on more recent studies which should in principle have been more cognizant of considerations of gender in adoption. We focused on peer-reviewed publications from 2012 to 2025, a period that reflects the substantial expansion of biofortification research and the integration of gender and empowerment dimensions in LMIC contexts. While early work on biofortified crops began in the 2000s, particularly through the HarvestPlus initiative, the number of studies increased markedly after 2012 following the release of multiple biofortified varieties (e.g., iron beans, vitamin A maize, and orange-fleshed sweet potato) and growing recognition of the need to address gender dynamics in adoption and impact assessments. The search strings used were:

(“biofortified crops” OR “biofortification” OR “biofortified varieties”) AND (“smallholder farmers” OR “smallholder agriculture” OR “rural farmers” OR “subsistence farmers”) AND (“low-income countries” OR “middle-income countries” OR “LMICs”)

We conducted four concept-specific searches (a-d) across five bibliographic databases, recording the number of records retrieved from each search. Four searches (i.e., a to d above) were conducted across the five databases. The first search (a) screened for studies on “biofortified crop(s)” and smallholder farmers, the second (b) screened for studies on adoption of “biofortified crop(s)” and gender, the third (c) screened for studies on “biofortified crop(s)” and empowerment effects while the fourth (d) screened for studies on “biofortified crop(s)” and nutrition or health outcomes. All four searches were delimited to studies conducted in low- and middle-income countries (LMICs) and within smallholder farming contexts, using country filters and corresponding Boolean terms.

We included peer-reviewed primary research articles and excluded review articles, theses/dissertations, protocols, conference papers, and abstracts, as well as non-English articles, identifying 121 studies which met our criteria (Figure 1). Quality assessment of the selected research articles followed the Joanna Briggs Institute (JBI) Critical Appraisal Tools (Porritt et al., 2014). The JBI Critical Appraisal Tools were used because they provide a comprehensive checklist for assessing the quality of a wide range of studies including case–control, case series, cohort, qualitative, quasi-experimental, systematic review, and prevalence studies (JBI, 2022). Using the response options ‘unclear’, ‘not applicable’, ‘yes’, and ‘no’, based on each article’s geographical location, study design (i.e., qualitative or quantitative), sample and population size, and sampling methods; data extracted was compiled into tables.

Our systematic search across five databases yielded 11,569 records, following the removal of 179 duplicates (Science Direct, n = 1,710; Web of Science, n = 3,401; Google Scholar, n = 4,532; PubMed Central, n = 843; and ProQuest, n = 1,104; Figure 1). Of the screened records, 121 studies met the inclusion criteria, which required empirical evidence on biofortified crops in smallholder contexts within low- and middle-income countries and relevance to adoption, gender, empowerment, or nutrition and health outcomes. Records were excluded if they fell outside these settings, lacked empirical data, or did not involve biofortified crops. Analysis of biofortified crop publications between 2012 and 2025 reveals a highly uneven global and crop specific distribution of studies (Figure 2; Tables 1, 2). The published biofortification research studies are concentrated in Africa, South and Southeast Asia, and parts of Latin America, whereas Europe and much of North America show minimal activity (Figure 2a). High iron and high protein traits account for the largest proportion of the studies, representing 33 and 20% of reviewed publications, respectively, while other biofortification traits including high zinc, combined high iron and zinc, and provitamin A are less frequently reported (Figure 2b). At the crop level, common bean and maize are the most frequently studied crops for biofortification, together comprising nearly half of all primary research publications, followed by rice and wheat, while pearl millet, lentil, cassava, sweet potato, cowpea, and yellow potato are comparatively underrepresented (Figure 2c). Our results highlight geographic, crop and trait specific disparities in biofortification research and indicate potential gaps for future investment to ensure broader coverage of micronutrient rich crops across diverse agroecological regions.

Between 2012 and 2025 biofortification studies have primarily focused on staple crops enriched with iron, zinc, pro-vitamin A, and protein, with notable geographic clustering. High iron crops were most frequently studied, particularly common bean, which accounted for over 33% of the reviewed publications across Sub-Saharan Africa (e.g., in Rwanda, Burundi, Kenya, Malawi, Zimbabwe, Uganda, and the Democratic Republic of Congo - DRC), while high iron wheat, pearl millet, lentil, and cowpea were studied in Pakistan, India, West Africa, and Brazil, respectively. Iron-enriched crops are specifically bred to combat iron deficiency anemia (Beebe, 2020), which disproportionately affects women and children (Haas et al., 2016; Vaiknoras and Larochelle, 2021). Zinc-enriched crops, on the other hand, appeared in 20% of studies, and are increasingly being promoted in the Global South (Lockyer et al., 2018), as zinc deficiency is associated with weakened immunity and impaired cognitive development (Khan et al., 2022; Lowe et al., 2024). The studies of high zinc crops were concentrated in rice and wheat, with most studies conducted in Bolivia, Colombia, Bangladesh, India, and Pakistan, with a single report on yellow fleshed potato in Peru. Studies on crops enriched with both iron and zinc were less common but included studies on common bean in Colombia, pearl millet in Burkina Faso and India, lentil in India, rice in Indonesia, and wheat in India.

Provitamin A biofortification studies were focused on cassava in Ghana and Nigeria, maize in South Africa, and sweet potato in Malawi and Uganda. Orange-fleshed sweet potato (OFSP) is being promoted to address Vitamin A deficiency (Neela and Fanta, 2019; van Jaarsveld et al., 2005), a leading cause of childhood blindness and impaired immunity (Adetola et al., 2020). OFSP promotion efforts, led by both government and NGO-led programs are considered to have had variable success in reaching smallholder farmers (Gatto et al., 2023; Low and Thiele, 2020; Wongnaa et al., 2024). High protein crop varieties were predominantly studied in maize across Mexico, Nigeria, the Philippines, India, and Zimbabwe, with some studies on high protein rice in India.

From the 121 papers included in our evidence review, we identified 114 distinct biofortified crop varieties reported between 2012 and 2025, spanning varieties displaying iron, zinc, pro-vitamin A, and/or protein enrichment. High iron crop varieties were the most widely represented, dominated by common bean varieties such as RWR2245, MAC44, and RWV3317, which were released in Rwanda, Burundi, Kenya, Malawi, Zimbabwe, Uganda, and the Democratic Republic of Congo (DRC). High iron wheat varieties (i.e., Pirsabak-2013, Janbaz, Atta Habib) were studied in Pakistan, while pearl millet varieties (e.g., CHAKTI, ICMP 177002) were studied in West Africa and India, along with lentil varieties (Pusa Ageti Masoor) in India. Zinc biofortification studies were concentrated in South Asia and Latin America, involving rice varieties such as BRRI dhan42 and Inpari IR Nutri Zinc, and wheat varieties (including Zincol-2016 and HI1636). A single study of a yellow potato variety biofortified with zinc (CIP311623.75) was recorded in Peru. Dual-enriched varieties (iron and zinc) were less frequent but were studied, including BIO-101 and BIO-107 common bean in Colombia, Dhanshakti pearl millet in India, and B14746E rice lines in Indonesia. Provitamin A studies included cassava in Ghana and Nigeria (Apomuden, IBA154800), maize in South Africa (PVAH-62), and orange-fleshed sweet potato in Malawi and Uganda (e.g., Zondeni, NASPOT 8). High protein crop variety studies were mainly represented by maize varieties in Mexico, Nigeria, the Philippines, India, and Zimbabwe (Sac Beh, Obatampa, HQPM-1, SC527), and a single rice variety (CR Dhan 310) in India. Together, these studies suggest regional alignment between biofortified crop types and local staple crops, with Africa and South Asia emerging as areas where micronutrient deficiencies are most severe and biofortification is being strategically implemented.

Gender plays a crucial role in shaping preferences for different traits, varieties, crops and cropping systems (Mwende et al., 2024; Nidumolu et al., 2022; Weltzien et al., 2019; Zimba et al., 2025). The process of breeding for biofortification traits (e.g., increased levels of micronutrients, reduced anti-nutritionals) can have direct effects (e.g., orange color in high provitamin A lines) and could potentially have (in rare instances) inadvertent indirect knock-on effects on other traits (e.g., cooking time, shelf-life). Although likely rare to non-existent in practice, in theory the latter could occur in situations where genes or alleles associated with biofortification traits are genetically linked to other agronomic or quality traits (i.e., in such instances genetic selection for biofortification traits can potentially have knock on genetic linkage effects on other traits). In addition, biofortification efforts are typically focused on specific staple crops where the scale of impact can be maximized. Genetic linkage effects on other traits. Where they occur, differential gender preferences that arise specifically for biofortified vs. non-biofortified crops can affect the adoption and acceptability of biofortified crop varieties (McDougall et al., 2022), influencing access to seeds, cultivation decisions, and the distribution of benefits (Gilligan et al., 2020; Hirpa Tufa et al., 2022; Launio et al., 2018; Nchanji et al., 2023). In our interpretations, we considered particularly the interactions between economic empowerment and the broader framework of the multi-dimensional impacts of gender on the uptake of biofortified crops (Table 2).

Of the 121 reviewed research studies, 35 explicitly considered gender as a factor in adoption and use of biofortified crops (Table 2). In Supplementary Table 1 we provide a summary of the study design, sample size, scope, key findings, conclusions and recommendations on a study by study basis. In general, the studies support the hypothesis that gendered power relations within households and communities can affect adoption of biofortified crops (for cultivation and/or consumption), although impacts vary by crop, region, and social context (Supplementary Tables 1, 2). Across Sub-Saharan Africa, women’s autonomy over farming decisions was indicated to be associated with higher adoption of crops such as iron-biofortified beans and orange-fleshed sweet potatoes (n = 11), whereas in households where men retained control over seed purchases and land allocation, biofortified crops were often deprioritized in favor of commercially oriented staples (n = 4). In South Asia, women’s influence was often exercised indirectly through food preparation and intra-household allocation of nutrient-rich foods, while in Southeast Asia, male out-migration left women as primary cultivators but with limited authority over market engagement (Table 3). In Latin America and West Africa, women’s participation in nutrition programs and cooperatives facilitated adoption of biofortified crops, while men continued to dominate formal markets and access to credit. Such regional differences suggest that gender relations, rather than individual preferences alone, can shape the success of biofortification interventions.

Most studies focusing on gender emphasized the nutritional implications of biofortified foods for women and children, particularly women of reproductive age who face heightened risks of micronutrient deficiencies (Vaiknoras et al., 2019). For example, iron deficiency anemia contributes to maternal mortality and adverse birth outcomes (Mulambu, 2017), making women key targets for biofortification strategies. However, the possible benefits of biofortified foods are mediated by gendered roles: women often shoulder increased caregiving burdens when family members suffer from micronutrient-related illnesses, while also acting as gatekeepers of household food consumption. Knowledge and awareness emerge as decisive factors. For instance, more educated women were more likely to adopt zinc biofortified rice in Bangladesh (Valera et al., 2025), while targeted nutrition education and community outreach increased uptake of OFSP in Kenya (Mulwa et al., 2023). Education and training can increase uptake of biofortified crops in a number of ways. For instance, it can encourage adoption by women farmers and household members of (a) biofortified varieties, (b) home consumption of biofortified varieties grown on the farm holding and/or (c) purchase in the market of biofortified foods grown by other farmers. For instance, 54% of interviewed households in the OFSP study in Kenya purchased OFSP from the market, with the remainder having grown the crop (Mulwa et al., 2023). Apart from targeting women with information, discussions or engaging in groups through community outreach may boost adoption rates for both cultivation and consumption, particularly if women can discuss collectively and critically analyze the pros and cons of adoption of biofortified crops or foods.

The availability and accessibility of seeds of biofortified crop varieties can be a factor where adoption is influenced by gender. Even where seed of biofortified crop varieties may be available on the market, the format in which the seed is sold can have a gender-related impact. In Rwanda, Vaiknoras et al. (2019) conducted a national-scale household survey to assess how different delivery approaches impacted the adoption of high iron beans among men and women, concluding that formal delivery systems accelerated the rate of adoption of the biofortified beans. They also found that peer-to-peer diffusion through social networks increased the rate of adoption. A key gender-related finding was that women farmers dis-adopted biofortified beans more slowly than male farmers. Vaiknoras et al. (2019) highlighted that while increasing women’s access to extension will increase levels of initial adoption of biofortified beans, subsequent dis-adoption or re-adoption is not typically influenced by formal extension.

While trait-preference convergence can occur, men and women can also value different crop traits, as argued by McDougall et al. (2022), thus shaping crop variety adoption pathways. For instance, it is often dichotomized that women prioritize taste, cooking quality, and nutritional value, while men emphasized yield and stress tolerance (e.g., Esuma et al., 2019; Jenkins et al., 2018). Indeed, these types of gender-based differences were evident across many of the cassava, sweet potato, maize, and rice adoption studies in this evidence review (Asante et al., 2023; Bacud et al., 2024; Mulwa et al., 2023), supporting the argument that crop breeding programs need to balance agronomic performance with consumer-preferred traits (Tufan et al., 2025; Voss et al., 2021; Weltzien et al., 2019). In studies on sweet potato adoption in Uganda, women farmers tended to show a preference for culinary and nutritional traits, such as taste and nutrient content, while men tended to prioritize agronomic traits such as yield and stress tolerance (Gilligan et al., 2020). Similarly, in a study of biofortified cassava adoption in Nigeria (Olaosebikan et al., 2019), female farmers were more likely to adopt nutritionally enhanced varieties due to their perceived benefits for household health, suggesting an alignment with nutrition-sensitive agriculture.

While higher yields are a separate breeding goal that is largely independent of micronutrient biofortification as a trait in crop breeding programs, some biofortified crop varieties may have been bred for both higher yields and higher levels of the target micronutrient. In such instance, increased yields from a variety can provide a varietal platform for the biofortification trait to “piggy back” upon, to increase likelihood of adoption by smallholders. For instance, in Rwanda, the iron-biofortified bean variety RWR2245 delivered 20–49% higher yields than traditional bush beans. Households growing RWR2245 extended the duration of self-produced bean consumption by 0.64 months, reduced reliance on market purchases by 0.73 months, and were 12% more likely to sell beans, thereby improving iron intake directly and supporting household income indirectly (Vaiknoras and Larochelle, 2021). A key consideration is whether biofortified crops or foods have any price premium in the marketplace specifically associated with their additional biofortification properties. While (Kolapo and Kolapo, 2021) found that smallholder farmers in Nigeria cultivating biofortified cassava experienced a 39.1% increase in per-capita total expenditure and a 29.7% rise in per-capita food expenditure, it was unclear whether the increased income arose from higher yields (unrelated to the biofortification trait) or to a premium in the marketplace for biofortified produce, or a combination of both.

Social norms can influence how biofortified crop cultivation and management tasks can be gender-specific, potentially affecting decision-making and who benefits from the crop. Jenkins et al. (2018) investigated the adoption and retention of OFSP in households headed by both men and women smallholders in Mozambique. Among the factors identified were access to planting material, taste preferences, sensory qualities, agronomic traits, lack of capital for agri-inputs and labor, environmental conditions, unstable markets, and limited sharing of technical information across smallholder farmer networks. The study by Adekambi et al. (2020) which focused on pro-vitamin A cassava in Ghana, identified high yields, early maturity, taste of the roots and leaves, and pest, disease, and drought tolerance as important factors governing adoption. In the Jenkins et al. (2018) study many of the smallholder participants perceived biofortified sweet potato cultivation and management to be governed by gender-specific roles and responsibilities, where men and women often engaged in different aspects of production, preservation, and marketing.

Post-harvest processes can also display gender differentials. In Nigeria, women indicated high processing costs, low market prices, and middlemen exploitation as barriers to adopting biofortified cassava, while men highlighted lack of processing equipment as a barrier (Olaosebikan et al., 2019). For cassava, most cassava production and processing activities were found to be primarily carried out by women, while men were more involved in land preparation and selling of biofortified cassava products (Olaosebikan et al., 2019).

Market access can also be shaped be gender. For instance, some women smallholders may have less direct engagement with formal seed markets than their male counterparts, limiting their access to biofortified seeds. In addition, men may have responsibility for purchasing seeds – where this occurs, biofortified crop adoption can depend on male farmers’ emphasis on commercial viability over nutritional attributes. In this arena, Jenkins et al. (2018) concluded that a possible strategy to increase adoption of biofortified crops could be to increase focus on women as vendors.

Age and education levels also can influence adoption of biofortified crop varieties. In Pakistan, the levels of education of the family and having infants in the household were shown to positively impact the adoption of zinc-enriched wheat (Rizwan et al., 2021). In South Africa, Govender et al. (2019) found that the acceptability of OFSP varied across age groups, where older women (particularly those with limited formal education) were sometimes less willing to shift from traditional crop varieties, citing concerns about unfamiliar farming practices.

Power dynamics and roles within the household can also affect adoption of biofortified crops. In Uganda, Gilligan et al. (2020) examined the importance of gender dimensions of household decision-making and bargaining power in the adoption of OFSP, and concluded that the probability of OFSP adoption was unaffected by the joint or exclusive control of assets by females at the household level. In Zimbabwe, Kairiza et al. (2020) evaluated the relevance of gender in the adoption of fortified foods in a household, and found weak statistical evidence that women-led households were more likely to adopt fortified products compared to male-headed households.

The limited access for many women smallholders to resources and assets (e.g., credit, extension services), land control can be a barrier to adopting biofortified crops. Studies from Nigeria (Olaosebikan et al., 2019) and Bangladesh (Meerza et al., 2023) indicated that women farmers were often more vulnerable than men to economic constraints, hindering their ability to invest in biofortified crops, especially when credit access was limited. The provision of gender-sensitive training and community-based supports, via Farmer Producer Organizations (FPOs) and Self-Help Groups (SHGs; Jain et al., 2024), was found to support women’s empowerment and improve adoption rates in India, indicating that broader empowerment programs can provide a stronger enabling environment for adoption of biofortified crops by women smallholders.

The sensory attributes of foods made from biofortified crops emerged as an important factor affecting adoption of foods or dishes derived from biofortified crops, with the potential for gendered preferences shaping household consumption. Women, as primary food preparers, expressed needs for consistency regarding sensory attributes such as color, texture, or taste of foods derived from biofortified crops, where deviations from the sensory properties of foods from conventional varieties could act as a barrier or an opportunity for adoption for consumption in the household. For instance, in Pakistan, Rizwan et al. (2021) studied factors affecting consumer acceptance of zinc-enriched wheat, and found that both women and men placed more emphasis on the appearance of Chapati made from zinc wheat. In Ghana, Adekambi et al. (2020) found no evidence of adoption of biofortified cassava being affected by cassava sweetness. In contrast, in Tanzania Mwiti et al. (2020) reported good taste, higher nutritional value, and root firmness as key reasons for farmers’ willingness to pay for non-biofortified sweet potato vines at the expense of biofortified ones. In Colombia, Beintema et al. (2018) documented that children preferred the biofortified bean variety BIO-107 over local varieties based on color, taste, and smell. In South Africa, a study by Awobusuyi and Siwela (2019) reported that the surveyed participants preferred Amahewu (a traditional beverage) prepared using provitamin A maize because of its aroma, color, and taste.

For many biofortified crops, acceptability among women and men was influenced by grain quality. In Bolivia and Colombia, Woods et al. (2020a) found that the acceptability of zinc-enriched rice was influenced by the grain quality properties (including grain nutrient content, grain size, texture, aroma, and cooking time). Consumers, particularly women responsible for food preparation, often compared biofortified zinc rice to conventional high-quality rice varieties, where any deviations in grain appearance or cooking properties sometimes led to hesitancy in adoption for consumption in the household. In households where staple food choices were deeply ingrained in cultural norms, shifts to biofortified crops were more likely when the biofortified variety closely resembled preferred local varieties.

In Pakistan, Mahboob et al. (2020) investigated the impact of consuming zinc wheat on reducing the levels of zinc deficiency in male and female-headed households. While the household participants expressed willingness to access and consume biofortified flour due to anticipated health benefits, there were additional knowledge communication activities that were required. The study found that the local community, including female health workers and local leaders (Jirga), should also be persuaded to support the dissemination of information on biofortified flour to increase levels of acceptance and awareness, due to their social influence. Another study in Pakistan by Mahboob et al. (2022) used focus group discussions to explore the perceived contribution of biofortification to food security and health. The study also investigated sensory and baking properties, along with willingness to pay for the biofortified flour. The household participants indicated that biofortified flour had good bread-making qualities and taste.

Behavioral and informational interventions can be mediators of adoption and consumption of biofortified crops. In a randomized trial involving 15 Kenyan villages, Ojwang et al. (2021) evaluated school-based and phone-mediated communication interventions designed to promote orange-fleshed sweet potato (OFSP). The approach enhanced caregiver knowledge of OFSP production and nutrition, and increased household consumption. The Okello et al. (2022) study in Ethiopia with 360 primary school children evaluated ways of encouraging consumption of biofortified OFSP in school meals. Children were randomly assigned to one of two interventions: (1) receiving information about the nutritional benefits of OFSP, or (2) receiving the same information plus seeing OFSP linked to an aspirational figure (i.e., a well-known local athlete). The study found that information alone did not increase children’s OFSP consumption, but combining information with the athlete role model led to a significant increase. The authors concluded that targeted, low-cost school-based communication strategies can help improve acceptance of biofortified foods among children. However, a study by Lagerkvist et al. (2016) in Kenya reported more complex relationships being consumer acceptance and provision of information in different formats.

Shikuku et al. (2019) conducted household surveys in Tanzania to examine impacts of biofortified sweet potato on food and nutrition security. It was concluded that (a) the nutritional and agronomic knowledge of farmer households, (b) adoption of Vitamin A sweet potato, and (c) food security levels were increased through their participation in the biofortified sweet potato project. However, the effects of the biofortified sweet potato project on nutrition were found to be weak. Timely access to biofortified seeds and capacity building were recognized as crucial in scaling the adoption of biofortified varieties in rural households.

Empowerment can be viewed in terms of an expansion in decision-making regarding the choice of agricultural inputs or methods, leadership in making changes, asset ownership, and income security (along with associated improvements in nutrition and health). In a systematic review, Aziz et al. (2022) reported a positive association between women’s empowerment and food security. In principle, biofortification programs could contribute to economic empowerment if they created new or increased income-generating opportunities. For example, women involved in processing and marketing of biofortified foods (e.g., OFSP puree, iron-rich bean flour, or zinc-enriched rice products) might have increased financial independence and bargaining power within their households. While biofortified crops in themselves are unlikely to confer broad empowerment outcomes for women smallholders, gender empowerment could create an enabling environment for adoption of biofortified crops and the realization of health and nutritional benefits from their sale and consumption. Across the 121 primary studies that we reviewed, 13 made some reference to gender empowerment dimensions.

The included studies on OFSP and iron-biofortified beans suggested that women who adopted these biofortified crops could gain increased influence over household food choices, as their role in ensuring family nutrition became more recognized. Households growing biofortified varieties (e.g., iron-biofortified beans; Vaiknoras and Larochelle, 2021), were more likely to sell surplus production. For example, in Rwanda, Vaiknoras and Larochelle (2021) evaluated the effect of high iron beans on the proportion of land cultivated under beans, household yield, bean consumption, sales, and purchases. Growing the biofortified variety RWR2245 increased the probability of sales by 12%, reduced bean purchasing time by 0.73 months, and increased the consumption period by 0.64 months in both male and female-managed farms.

The general theory of change for biofortified crops is that their cultivation will translate into consumption (either directly or indirectly) and thereby lead to improved nutrition and health outcomes for those who consume foods derived from the biofortified crops. All aspects of this theory of change can potentially be affected by gender roles and relations in smallholder communities.

To determine whether the intended nutrition and health impacts arise as a result of consumption of biofortified crops, there are a range of different trial types and designs that can be considered (e.g., efficacy trials, effectiveness trials, randomized controlled trials, intervention trials, behavior change trials) A number of studies have demonstrated strong evidence of nutrition and health impacts arising from consumption of biofortified crops. These include efficacy (Low et al., 2007) and effectiveness (Hotz et al., 2012) trials in Mozambique where OFSP consumption increased vitamin A intake and vitamin A status in deficient populations (women, children). Similar strong evidence was observed for provitamin A cassava in randomized controlled trials in Kenya (Talsma et al., 2016) and Nigeria (Afolami et al., 2021) where serum retinol concentrations in vitamin A deficient children were observed. Randomized controlled trials in Rwanda provide robust evidence that high-iron biofortified beans significantly improve iron status in young women (Funes et al., 2024; Haas et al., 2016; Wenger et al., 2019). Complementary experimental work has shown that improved iron status is associated with measurable gains in physical work efficiency among iron-depleted sedentary women (Luna et al., 2020), underscoring the functional significance of iron improvements. Evidence of impacts of consumption of iron biofortified pearl millet on iron status was detected for children (Finkelstein et al., 2015) and adolescents (Scott et al., 2018) using randomized controlled trials in India, where the study on adolescents also demonstrated improved cognitive performance.

However, there have also been some trials where weak or mixed evidence of impacts on nutrition and health outcomes have been detected following consumption of biofortified crops. These consisted of studies where (a) increased levels of intermediate biomarkers (e.g., β-carotene) were observed but not for the ultimate biomarker (e.g., retinol; Lowe et al., 2021), (b) effects were limited to subgroups of the trial (Mehta et al., 2022), and (c) health outcomes were not observed. For instance, a cluster-randomized trial in Zambia involving consumption of provitamin A maize by children, detected increased levels of β-carotene concentrations but not higher levels of retinol in the serum (Palmer et al., 2016a).

Finally, there are a number of studies where there was no observed nutritional or health outcome from the consumption of the biofortified crop. These include studies on zinc biofortified wheat in Pakistan (Gupta et al., 2025) and zinc biofortified rice in Bangladesh (Herrington et al., 2023). The study by Sazawal et al. (2018) in India also observed no significant difference in zinc levels between consumers and non-consumers of zinc wheat, with similar results observed by Cercamondi et al. (2013) in Benin (iron-biofortified millet). The weaker evidence to date associated with zinc biofortified crops possibly due to fewer trials, shorter duration studies, insensitive biomarkers, differences in study designs (Gulyas et al., 2025; Ofori et al., 2022). In addition, while higher micronutrient levels due to breeding can be present under favorable field and growth conditions, the levels and bioavailability of some micronutrients can be affected by genotype by environment effects that can occur during production (Hummel et al., 2018a) or post-harvest handling (Huey et al., 2024) stages of the crop.

In Zambia, children consuming pro-vitamin A maize had higher serum β-carotene levels, although serum retinol and deficiency prevalence were unchanged (Palmer et al., 2016b). In India, adolescents consuming iron-biofortified pearl millet had higher daily iron intake, which translated into improved iron status and enhanced cognitive performance, with reaction times on attention and memory tasks improving roughly twice as much as controls (Scott et al., 2018). Among children under five in Mozambique, consumption of OFSPs reduced diarrhea prevalence by 11.4 percentage points (and by 18.9 points) in children under three_ while also shortening the duration of diarrhoeal episodes (Jones and de Brauw, 2015). Jongstra et al. (2020) investigated iron absorption from iron-rich OFSP in Malawi and high iron potatoes in Peru, and demonstrated that that consumption of the iron biofortified varieties increased iron absorption 1.9-fold (p < 0.001). The study by Murray-Kolb et al. (2017) demonstrated the efficacy of biofortified iron beans in improving cognition in women of reproductive age in Rwanda.

De Moura et al. (2016) conducted studies on Vitamin A intake in Bangladesh, Indonesia, and the Philippines, showing that substituting biofortified rice for regular white rice (under an ‘optimistic’ scenario of 20 ppm and 70% substitution) reduced the incidences of Vitamin A inadequacy by 78 and 71% in women and children in Bangladesh. In the Philippines and Indonesia, the prevalence of Vitamin A deficiency decreased by 55–60% in women and by nearly 30% in infants (De Moura et al., 2016). In Ethiopia, Gunaratna et al. (2019) demonstrated that quality protein maize reduced protein inadequacy from 34 to 19% during the food-insecure agricultural season. Improved nutrition status of populations consuming biofortified foods has been demonstrated for many crops in many regions, including: in studies by Finkelstein et al. (2019) in Mexico, Sheftel et al. (2017) in Zambia, Finkelstein et al. (2015) in Zambia, Zhu et al. (2015) in Nigeria, and Haas et al. (2016) in Rwanda.

Sensory studies, nutrition promotion and behavior change interventions can also have an impact on the likelihood of nutrition and health outcomes being realized from consumption of biofortified crops. Sensory testing studies with biofortified crops and varieties have been done for OFSP with women caregivers in Kenya (Lagerkvist et al., 2016) and households with children in Malawi (Hummel et al., 2018b). While the Malawi study concluded that sensory and cultural attributes can influence acceptability and consumption of OFSP varieties in households with children, the Kenya study had a counter-intuitive finding whereby detailed information on nutritional benefits decreased consumer acceptance. Ojwang et al. (2021) found that nutrition education (using learning materials and phone messages) targeted at preschool children and their caregivers in Kenya had a positive “nudge” effect on increasing OFSP consumption levels among the preschoolers.

While some biofortified crop varieties (e.g., high vit A maize, cassava or sweet potato) can be distinguished by the color of the tuber or the grain, others (e.g., high iron or zinc varieties) cannot easily be distinguished. This poses major problems for ensuring identity, traceability and avoiding mix ups with non-biofortified counterparts. In the absence of regular lab testing quality control, there is a high of fraud. Thus also applies to the marketplace where biofortified varieties cannot easily be visually or financially differentiated from less nutritious counterparts.

As the foods consumed with biofortified crops (and the cooking methods) can affect the extent by which the increased micronutrients are bio-accessible or bioavailable to those eating them, there is a major education and training gap for women in smallholder communities to be trained in how to cook meals with biofortified components that can effectively deliver nutrients. Where different members of households have differential access to food components that can enhance or inhibit bio-accessibility of biofortified foods, there may be an indirect gendered link between intrahousehold food access and bio-accessibility outcomes from biofortified foods.

Where gender empowerment effects on women are more (or less) likely to take better care of children and household members, then there will be a link between empowerment and how biofortified varieties are accessed (grown, purchased) and consumed in smallholder community households. In any cases where gender empowerment effects could lead to a decline in care for children (e.g., due to income generating activities outside household), there could be the possibility of negative effects also on the choice/consumption/cooking of biofortified crops.

Nonetheless, the overall evidence to date indicates that biofortified crops can deliver nutrition and health benefits, but that gendered access to resources, decision-making power, and information channels can shape consumption, nutritional and health outcomes. We conclude that significant knowledge gaps still exist in understanding the impacts of biofortified crop adoption and consumption on broader questions of food security and equity in food systems transformation processes. In Figure 3, we synthesize these impacts and the potential inter-linkages between access to biofortification and lifestyle outcomes.