Vitamin B12 Status Upon Short-Term Intervention with a Vegan Diet-A Randomized Controlled Trial in Healthy Participants.

Plain Language Summary

Veganism is growing in western societies and with it comes an increased risk of vitamin B12 deficiency which is principally found in animal products. Vitamin B12 is essential for multiple biological functions including DNA synthesis, digestive function and detoxification processes. It can take 2-5 years to exhaust natural stores of B12 within the body so deficiency risk is considered safe. This 2017 randomised control trial compared vitamin B12 status in 53 healthy omnivore subjects with 26 participants following an unsupplemented vegan diet for 4 weeks and the remaining 27 participants a meat-rich diet. The aim of the study was to answer two questions; (a) Do vitamin B12 markers respond to short-term dietary intervention with a meat-rich or a plant-based diet? and (b) Do meat-rich and vegan diets have an impact on plasma markers of inflammation and cardiovascular disease? Blood and urine samples were taken before and after the 4-week dietary protocol to also measure vitamin D status, Folate and Homocysteine levels as a marker for inflammation. The serum vitamin B12 levels (indicative of dietary B12) dropped significantly from 362.9 +/- 110.9 ng/mL to 296.1 +/- 94.1 ng/mL in the Vegan Diet group (p < 0.001) and remained stable in the Meat Diet group. Other markers measuring cellular B12 metabolism did not significantly vary. The short-term nature of the trial demonstrated rapid decrease in holo-TC, the bioactive form of vitamin B12 in plasma. The other blood and urinary markers demonstrated benefits to plant-based eating including reduced cholesterol intake and adequate profiles of nutrient and micronutrient status.