Recently it has been found that vitamin D is vital not only for our bones but also for many metabolic processes. It is synthesized in the body mainly through the effect of the sun’s ultraviolet radiation on our skin. Vegan foods can not contribute to the supply of vitamin D, as significant amounts are present only in foods of animal origin.
Vitamin B12 is not present in plant foods, so a long-term vegan diet can lead to deficiency unless dietary supplements are taken. Symptoms of deficiency can include trembling in the hands, weakness, memory loss, numbness, cold hands and feet, aversion to bright lights, and more. In general, careful selection and regular monitoring of B12 status are recommended.
Vitamin B6 (pyridoxine) has multiple metabolic functions, especially in amino acid metabolism, and is neurologically important. Especially for girls, it is important for hormone metabolism. About 14% of 14- to 18-year-old girls consume less than the recommended amount of vitamin B6. For vegans, the percentage is even higher, as vitamin B6 has low bioavailability in plant foods. Vitamin B6 is also essential for the synthesis of hormones such as serotonin, so symptoms such as depressed mood, increased irritability, nervousness, and loss of libido may also indicate vitamin B6 deficiency.