Vegetarians have high prevalence of Vitamin B12 deficiency. Vitamin B12 status in body is not reliably reflected by Total serum vitamin B12 concentration alone. Holotranscobalamin II is a bioactive B12 fraction which promotes specific uptake of vitamin B12 by cells. Circulating concentration of Holotranscobalamin II reflects the intake of B12 whereas total homocysteine indicates the metabolic ability.
Signs of Vitamin B12 deficiency:
A study conducted at a hospital in Pune showed that only 50 % male and 52 % female had normal plasma vitamin B12 concentration while 39% male and 30 % female had very low concentration. A total of 119 (forty-six male and seventy-three female) vegetarian young adults were enrolled in the study. The participants neither had clinical symptoms of vitamin B12 deficiency nor were taking vitamin B12 supplementation or any drugs influencing vitamin B12 absorption.
Authors of the study recommend vegetarians to take a supplement of vitamin B12 to ensure adequate supply of the micronutrient; especially for females in reproductive age to prevent the risks associated with maternal–fetal vitamin B12 deficiency. Authors suggest a diagnostic cut-off level of plasma vitamin B12 (105 pmol/l), Holotranscobalamin II (22·6 pmol/l) and Homocysteine (17·6 µmol/l for females and 27·0 µmol/l for males) in Indian vegetarian.