Is an iron supplement going to bother my stomach?
Nausea and constipation are unfortunately side effects from iron in some people. If this happens, try lowering the dose, taking the supplement with food, or using a daily stool softener (such as docusate sodium) along with the iron. Occasionally dark stools may occur as a result of iron supplementation. As long as this occurs only after starting an iron supplement, without a tarry or bloody look to the stool, it is not worrisome.
Can my iron level get too high from taking a supplement?
Yes. Iron toxicity is rare but possible in otherwise healthy individuals.
I heard I need to take vitamin C with iron?
While vitamin C does improve the absorption of iron, taking them together is not strictly necessary.
I’m planning an extended thru-hike. For how long do I need to continue the iron supplement?
As many of the studies on iron and altitude have been conducted at short-term athletic training camps, this is unclear. If the body is fully altitude acclimatized and the ferritin level is normal, food sources may be adequate.
What about food? Can I just get iron in my food?
Certainly this is possible, though if your iron stores are low, you either have not been getting enough, or may have a medical condition which is causing the low iron. Your physician can help you determine the cause and choose the best course of action. If more dietary iron is needed, trying to replete an iron deficiency with 100mg/day from regular food sources would be particularly difficult. The NIH has an Iron Fact Sheet for Health Professionals
that discusses the USDA recommended daily allowance for iron. This is 18 mg daily for women aged 19 – 50 and 8mg for women over 50 and for men.
Below is a chart of iron content in common foods. We tend to think of iron being present in red meat, but ½ cup of chickpeas or kidney beans has roughly the same amount of iron as 3oz of red meat. For backpacking, a quick internet review of the nutrition information of a popular brand
of dehydrated meals (with meat) shows only 1-3mg of iron per serving. Interestingly, inspection of some vegetarian dehydrated meals in my own pantry show 4-7mg of iron per serving.