Best time to take b12
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Optimal Timing for Vitamin B12 Supplementation
Importance of Vitamin B12
Vitamin B12 is essential for various bodily functions, including DNA synthesis, red blood cell formation, and neurological function. Deficiency in this vitamin can lead to severe health issues such as megaloblastic anemia, cognitive decline, neuropathy, and depression, particularly in vulnerable populations like vegetarians, vegans, and pregnant women1 2.
Daily vs. Weekly Dosage
Sublingual Dosage Efficacy
A study comparing two different sublingual dosages of vitamin B12 (350 µg/week vs. 2000 µg/week) in vegans and vegetarians with marginal deficiency found that both dosages were effective in restoring adequate serum concentrations of vitamin B12 and improving related metabolic markers1. However, the study concluded that a daily sublingual dosage of 50 µg/day (350 µg/week) is preferable over a single large weekly dose of 2000 µg, as it ensures better absorption and consistent serum levels1.
Pregnancy and Early Childhood
For pregnant women, especially in resource-poor settings, a daily dose of 50 µg of vitamin B12 from early pregnancy until six months postpartum has been shown to support better neurodevelopmental outcomes in children2. This suggests that daily supplementation is crucial during periods of rapid growth and development, such as pregnancy and early childhood.
Cognitive Function in the Elderly
In elderly populations, the relationship between vitamin B12 intake and cognitive function has been inconsistent. While some studies show no significant association, others suggest that markers of vitamin B12 status, such as methylmalonic acid and holotranscobalamin, are linked to a reduced risk of dementia and better global cognition4. This indicates that maintaining adequate vitamin B12 levels is important for cognitive health, although the optimal timing and dosage require further research.
Conclusion
The best time to take vitamin B12 appears to be daily, rather than in large weekly doses, to ensure consistent absorption and maintain adequate serum levels. This is particularly important for vulnerable groups such as vegetarians, vegans, pregnant women, and the elderly. Daily supplementation supports better overall health outcomes, including improved metabolic markers and cognitive function.
Sources and full results
Most relevant research papers on this topic
Effect of two different sublingual dosages of vitamin B12 on cobalamin nutritional status in vegans and vegetarians with a marginal deficiency: A randomized controlled trial.
Sublingual dosages of 350 g/week (350 g/day) of vitamin B12 are more effective than 2000 g/week (one large oral dose) in improving vitamin B12 nutritional status in vegans and vegetarians with a marginal deficiency.
RCT
Very Rigorous JournalThe effects of vitamin B12 supplementation in pregnancy and postpartum on growth and neurodevelopment in early childhood: Study Protocol for a Randomized Placebo Controlled Trial
Vitamin B12 supplementation during pregnancy and postpartum may improve early childhood growth and neurodevelopment in Nepalese children.
RCT
Large Human Trial
Rigorous JournalCombined biotin, folic acid, and vitamin B12 supplementation given during the transition period to dairy cows: Part I. Effects on lactation performance, energy and protein metabolism, and hormones.
Combined biotin, folic acid, and vitamin B12 supplementation during the transition period improves lactation performance, energy and protein metabolism, and hormones in dairy cows.
RCTRigorous JournalVitamin B12 intake and status and cognitive function in elderly people.
Current evidence on the relationship between vitamin B12 intake and cognitive function is insufficient for developing vitamin B12 recommendations.
Systematic ReviewDietary Intake of Vitamin B12 is Better for Restoring a Low B12 Status Than a Daily High-Dose Vitamin Pill: An Experimental Study in Rats
Dietary intake of vitamin B12 is better for restoring a low B12 status than a daily high-dose vitamin pill.
RCT
Animal StudyVery Rigorous JournalAbsorption of Vitamin B12 in Pernicious Anaemia: IV. Administration into Buccal Cavity, into Washed Segment of Intestine, or after Partial Sterilization of Bowel
Vitamin B12 administration into the buccal cavity, into a washed segment of the intestine, or after partial sterilization of the bowel can effectively improve pernicious anaemia and maintain reticulocyte levels.
Intake of vitamin B12 in relation to vitamin B12 status in groups susceptible to deficiency: a systematic review
Habitual B12 intake or an intake in line with the current Nordic recommended intake is insufficient to ensure adequate B12 status for all included populations.
Systematic ReviewLong term biweekly 1 mg oral vitamin B12 ensures normal hematological parameters, but does not correct all other markers of vitamin B12 deficiency. A study in patients with inherited vitamin B12 deficiency
Long-term oral vitamin B12 treatment ensures normal hematological parameters but does not correct all other markers of vitamin B12 deficiency.
Vitamin B12 Deficiency: Recognition and Management.
Vitamin B12 deficiency can cause megaloblastic anemia, neuropsychiatric symptoms, and should be managed with oral or intramuscular therapy.
Highly CitedA comprehensive review and meta-regression analysis of randomized controlled trials examining the impact of vitamin B12 supplementation on homocysteine levels.
B12 supplementation positively impacts lowering blood homocysteine levels, particularly when administered for longer periods and at larger doses.
Meta-Analysis