Department of Consumer and Food Sciences, University of Pretoria, Hatfield Campus, Pretoria, South Africa.
Crit Rev Food Sci Nutr. 2019;59(19):3211-3226. doi: 10.1080/10408398.2018.1546670. Epub 2019 Jan 13.
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.
自 21 世纪初以来，人们已经做出了巨大努力来应对由于铁、锌、碘和维生素 A 导致的隐性饥饿挑战。许多国家优先考虑维生素 A 缺乏症（VAD），正在寻找可行的替代策略，如生物强化。VAD 的一个主要原因是β-胡萝卜素向视黄醇的生物转化率低。本综述重点介绍了细菌生物合成类视黄醇的机会，特别是通过肠道微生物群。该假说的前提是，动物能够在肝脏和肠道组织中储存并及时将类胡萝卜素转化为视黄醇。这一理论具有许多科学见解，是实验性的。共生代谢、胆汁酸、脂钙蛋白和肠道微生物群的脂多糖的潜在串扰被报道对类视黄醇生物合成有重要贡献。肠道细菌通过主要由水平基因转移等事件驱动的遗传重构来响应这些因素。对一组选定的原核生物和真核生物的β-胡萝卜素 15、15'-单（二）加氧酶酶进行了系统发育分析，以验证这些假设。通过能够合成维生素 A 的肠道细菌等非遗传修饰生物体来阐明益生菌策略，将解决 VAD 障碍问题。
