Answer:
Ferrous sulfate is the form of iron that is most easily ingested. Ferrous gluconate, but may have less uncomfortable side effects. Supplements are also absorbed better if taken on an empty stomach.
Step-by-step explanation:
Iron from food comes in two forms: heme and non-heme. Heme is found only in animal flesh like meat, poultry, and seafood. Non-heme iron is found in plant foods like whole grains, nuts, seeds, legumes, and leafy greens. The absorption of most dietary iron occurs in the duodenum and proximal jejunum and depends heavily on the physical state of the iron atom. At physiological pH, iron exists in the oxidized, ferric (Fe3+) state. To be absorbed, iron must be in the ferrous (Fe2+) state or bound by a protein such as heme.