B12 doses above 25mcg is a complete waste and likely counterproductive
I believe the only reason most b12 are in high doses is because it's harder to create the low dose pills/shots so it doesn't make economic sense for manufacturers to make the correct dose. It has nothing to do with any health benefits to the consumer. I think taking the extreme doses common in otc b12 supps, while not documented to be dangerous, can have other negative effects not yet tested for. Think about, your body has to process the unnaturally high doses and get rid of it somehow.
https://www.ncbi.nlm...pubmed/24699807
High-dose compared with low-dose vitamin B-12 supplement use is not associated with higher vitamin B-12 status in children, adolescents, and older adults.
AbstractOver-the-counter vitamin supplements on the Canadian market are permitted to contain a daily vitamin B-12 dose of up to 1000 μg. Our objective was to determine the association between total daily vitamin B-12 supplement dose and markers of vitamin B-12 status in Canadians. Blood collected from a nationally representative sample aged 6-79 y (n = ∼5600) in the Canadian Health Measures Survey (2007-2009) was analyzed for serum vitamin B-12 and plasma total homocysteine (tHcy). Total daily intake of vitamin B-12 from single and multivitamin supplements was calculated. Individuals that indicated proton pump inhibitor or vitamin B-12 injection treatment were excluded from the supplement dose and tHcy analyses; folate-deficient individuals were also excluded from the tHcy analysis. Twenty-three percent of children, 12.3% of adolescents, and 25.5% of adults consumed a vitamin B-12-containing supplement. Supplement users had 33% higher serum vitamin B-12 and 4.2% higher prevalence of adequacy than did non-supplement users. Children and adolescents consuming >10 μg/d supplemental vitamin B-12 did not demonstrate higher serum vitamin B-12, higher prevalence of serum vitamin B-12 adequacy, or lower tHcy than did those consuming >0-10 μg/d. The association between serum vitamin B-12 reached a plateau at doses of >25 and >10-25 μg/d in adults aged 46-59 and 60-79 y, respectively. The prevalences of serum vitamin B-12 adequacy and normal tHcy, and tHcy did not differ by vitamin B-12 supplement dose in adults >45 y. In this cross-sectional study, vitamin B-12 supplement doses >10-25 μg/d were not associated with higher vitamin B-12 status in children, adolescents, or older adults compared with lower doses.
Edited by iseethelight, 15 April 2017 - 11:03 PM.
