Biofortification of kale with vitamin B12 and iodine for vegans using a vertical farming system.

Vitamin B12 and iodine deficiencies are significant public health concerns and exhibit greater severity among vegans and vegetarians. This study aimed to evaluate the effects of the multi-biofortification of kale with vitamin B12 and iodine in a hydroponic vertical farming system. During hydroponic cultivation, kale was treated with cyanocobalamin (CN) and KI for a week before harvest. Combination treatment with CN and KI (5 μmol/L each; CN5+KI5) enhanced accumulation efficiency compared with individual treatments, and the consumption of 67.9 g of multi-biofortified kale met the recommended dietary allowances of both vitamin B12 and iodine for adults. Moreover, CN5+KI5 treatment promoted the synthesis of specific secondary metabolites in kale, such as p-coumaric acid and 3,5-dicaffeoylquinic acid. Notably, CN and KI biofortification did not negatively affect kale's growth, visual quality, or sensory properties. Our findings demonstrate that multi-biofortification of kale with CN and KI is a promising strategy for addressing nutritional deficiencies in vegans.