I have low iron levels 5.7, i have had a colonoscopy and gastronoscopy and there was no bleeding found. i take iron supplements but still no change. ?

Gluten: You may have gluten sensitivity, which can damage your gut cells. Damaged cells may not do a good job of absorbing the nutrients you eat. Consider taking vitamin c as this enhances iron absorption. Consider switching to a different form of iron, such as polysacaride.

Another cause?: Is there another cause of your anemia? Specifically, i'm wondering if you have very heavy periods. Perhaps you are losing blood there.