I'm not an expert, but I would be surprised if slight anemia would have any impact at all on your ability to get insurance, or your rates. Most insurers know that anemia is really common for women, because we menstruate and lose blood.
Anemia can also be an issue for distance runners, and those people tend to be very healthy otherwise, and very insurable.
I probably wouldn't worry about it. (Frankly, also, I think the ACA's rules about pre-existing conditions would mean that stuff like this is a non-issue.)