I know there is an iron supplement with "Heme" iron, it has a better absorption rate & also there is a book called "What your DR might not tell you about Peri-Menopause" by Dr. John R. Lee. You can get copies on Amazon. It has a lot of useful info on supplements & vitamins, hormones & the changes that happen as a women ages...but it sounds like 1st her diet needs to be tweecked & a lot more iron rich foods added, asap.
Does she like spinach? my kids don't so much, but I puree it & add it to stuff they wouldn't notice it in, like pesto or sometimes homemade pasta sauce. If one of them knows it's there, she won't eat it. but it doesn't have a strong favor, so it hides well in darker foods. She doesn't like cooked carrots either, so I chopped them up super fine & add to pasta & soups & she eats them with no problems. I think it's just the idea of them...I hate liver, but it suppose to have a lot of iron, so if she likes it, fry it up!
You could also look up info on WebMD & check her symptoms there & see what it says. Good Luck...
Okay, I'm adding this a couple of days later, because I just read an article about Celiac Disease & alot of the symptoms are similar..the unexplained anemia & fatigue being tops on the list. Anyway, the gluten in wheat & other foods damages the small intestine so it can't absorb nutrients from food. something to look into, maybe