Significant efforts have been made to address the hidden hunger challenges due to iron, zinc, iodine, and vitamin A since the beginning of the 21st century. Prioritizing the vitamin A deficiency (VAD) disorders, many countries are looking for viable alternative strategies such as biofortification. One of the leading causes of VAD is the poor bioconversion of β-carotene into retinoids. This review is focused on the opportunities of bacterial biosynthesis of retinoids, in particular, through the gut microbiota. The proposed hypothesis starts with the premise that an animal can able to store and timely convert carotenoids into retinoids in the liver and intestinal tissues. This theory is experimental with many scientific insights. The syntrophic metabolism, potential crosstalk of bile acids, lipocalins and lipopolysaccharides of gut microbiota are reported to contribute significantly to the retinoid biosynthesis. The gut bacteria respond to these kinds of factors by genetic restructuring driven mainly by events like horizontal gene transfer. A phylogenetic analysis of β-carotene 15, 15′-mono (di) oxygenase enzymes among a selected group of prokaryotes and eukaryotes was carried out to validate the hypotheses. Shedding light on the probiotic strategies through non-genetically modified organism such as gut bacteria capable of synthesizing vitamin A would address the VAD disorders.

Micronutrient deficiencies, also known as “hidden hunger,” remain a pervasive public health issue in low- and middle-income countries, particularly among vulnerable populations within these countries. The main drivers of these deficiencies are poverty, limited dietary diversity, weak nutritional strategies, poor health service delivery and general health access barriers. This review assesses the prevalence, drivers, and consequences of selected micronutrient deficiencies: iron, iodine, zinc, vitamin A and vitamin D, within the scope of undernutrition, food insecurity, and socioeconomic inequity. The consequences associated with these deficiencies include stunted growth, increased susceptibility to illness, poor cognitive and social functioning, and deepened poverty. The primary strategies to address these deficiencies include dietary diversification, supplement provision, biofortification, and the production of fortified foods. Barriers to progress include the high cost of food, weak healthcare infrastructure, low educational levels, and ineffective policy implementation. Integrated food systems, personalised nutrition, and innovative food technologies have the potential to address both nutritional and health inequities. Addressing barriers to safe and nutritious food and healthcare systems in order to address health inequities requires integrated, multisectoral planning and contextual policy. Improving individual health outcomes is crucial, but addressing micronutrient deficiencies has a ripple effect throughout society, enabling economic development through poverty reduction and increased productivity.