The amount of time it takes for either treatment to take effect depends upon the severity of your B12 deficiency, and on the resulting health impacts of being deficient [4]
[2] For this reason, elevated serum homocysteine over 15 micromol/L and methylmalonic acid (MMA) over 0.271 micromol/L are considered better indicators of B 12 deficiency, rather than relying only on the concentration of B 12 in blood
1,2 Serum vitamin B 12 levels may be artificially elevated in patients with alcoholism, liver disease, or cancer because of decreased hepatic clearance of transport proteins and resultant higher circulating levels of vitamin B 12
Supporting a dominant role for diet composition in establishing the Firmicutes : Bacteroidetes ratio, previous work has shown that mice maintained on a high-fat diet had a similar cecal Firmicutes : Bacteroidetes ratio to those maintained on a high-carbohydrate diet 77
This may be an early indication that some nutrients may have therapeutic ranges