Hello Jeff,
I've been eating Dr. Esselstyn's recommended diet since August 2012, ~97% compliant. Over this period of time--and not before this period of time--my hemoglobin has been declining steadily and gradually. My hemoglobin was measured a couple weeks before I started the diet at 153 g/l, right on the median (according to my lab report). In October 2018 my hemoglobin was 128 g/l. The lowest point of the so-called normal range is 135 g/l (again according to my lab report). My last three hemoglobin measurements--which spanned 2018--were all below normal, though October's 128 g/l is the lowest I've seen so far. A graph of the many hemoglobin measurements I've had over 2012-2018 depicts a gently but relentlessly downward sloping trend line. The situation has drawn my doc's attention, and further investigations are underway.
My ferritin levels over the past year have been in a range--albeit low in the range--that my lab report describes as "iron deficiency unlikely." According to Cronometer, I typically consume at least 16 mg (all plant-based) iron daily. And I'm cognizant of techniques to improve the absorption of the iron I eat (tannins--no; vitamin C--yes). I've always taken a B12 supplement since starting Dr. Ess's diet. More broadly, Cronometer is telling me that I do and have always done a good job of getting the vitamins, minerals, etc. that I need.
My question for you at last: Are you aware of any science indicating that "normal" hemoglobin levels for healthy people who eat similar to me may be lower than levels for the general population?
Finally, I feel fine, very good in fact. I think I have excellent stamina for a 62-year old, and that hasn't changed to my perception as my hemoglobin has gradually dropped. A bit of a mystery.
Thanks much.