 Fish provides vitamin B12 in a macrobiotic diet, as bioavailable B12 analogues have not been established in any natural plant food, including sea vegetables, soya, fermented products, and algae.Although plant-derived foods do not naturally contain B12, some are fortified during processing with added B12 and other nutrients.Vitamin A, as its precursor beta-carotene, is available from plants such as carrots and spinach.