SNAP stands for Supplemental Nutrition Assistance Program. It is used by about half of the Medicaid beneficiaries who qualify for it.
Previous warnings about small trials apply here, but in a study in The Lancet, investigators assigned women with mild reductions in iron storage (serum ferritin levels of ~25 ug/L or less) but not moderate or severe anemia to receive 60 mg ferrous sulfate every day for two weeks or every other day for 4 weeks. Then the investigators checked their fractional iron absorption and total iron absorption.
Two weeks following treatment, the alternate-day group had higher fractional iron absorption (22% vs. 16% ) AND total iron absorption (175 vs. 131 mg).
To make sure that this was an effect of timing and not just splitting the dose, a smaller group of women was then assigned randomly either 120 mg FeSO4 daily or 60 mg twice daily and the testing process was repeated. In this case, there was no difference between the two groups.
So what's the take-home? First, there is no benefit (*ahem*, small study) in dividing iron doses into twice daily. Second, it might be beneficial, at least in this specific patient population, to give the iron less often, but for a greater length of time. Mechanism unknown, at least to me. I have some concerns about every-other-day dosing. It seems like a good way to drive down adherence to therapy. But the effect is promising. In an astonishingly British-sounding editorial (the authors are straight from Downton Abbey casting), one states that the results "are likely to lead to a more felicitous means of administering this widely used therapy." Felicitous, in case you were born west of eight degrees longitude, means "well chosen or suited to the circumstances." Or "pleasing and fortunate." But the latter definition will seem strange to anyone who's ever tried to pass a ferrous sulfate-laced stool.
Speculation is that this is related to fear of traumatic encephalopathy and concussion. Speculation on my part is that this is the beginning of a slow decline in football in the non-deep-south.
Justin Moore, owner of an iPhone, agrees. Don't be a phoneworm.