It was Christmas week 1990 in Oakland. Steven Bloom was wandering through The Lot, that timeless gathering of hippies that springs up in the parking lot before every Grateful Dead concert, when a Deadhead handed him a yellow flyer.
Because of the general safety of the vitamin, upper limits for normal intake do not exist. If your blood values for the vitamin fall below a range of 170 to 250 picograms per milliliter, you may develop a B12 deficiency.
For people without diabetes, the normal range for the hemoglobin A1c level is between 4% and 5.6%. Hemoglobin A1c levels between 5.7% and 6.4% mean you have a higher change of getting of diabetes. Levels of 6.5% or higher mean you have diabetes. The target A1c level for people with diabetes is usually less than 7%.