Iron (as ferrous gluconate)

Iron. The human body uses iron (a mineral) to make a protein (hemoglobin) in red blood cells to carry oxygen throughout the body so that cells may produce energy 1, 2, 3. There are two forms of dietary iron: heme and nonheme. Sources of heme iron include meat, fish, and poultry. Sources of non-heme iron include plant and iron-fortified foods, beans, lentils, flours, cereals, and grains 1, 2, 3. The iron requirement of the individuals determines the proportion of dietary iron absorbed 1. Heme iron is more easily absorbed (has more bioavailability) than non-heme iron 1, 2, 3. The absorption of non-heme iron is strongly influenced by its interaction with other meal components in the lumen of the upper small intestine and by its solubility, whereas heme iron is always well absorbed and influenced only slightly by other dietary factors 1.

Ferrous Gluconate (also called iron gluconate) is a form of mineral iron, taken orally 4. In addition to being absorbed in the small intestine and stomach, ferrous gluconate combines with apoferritin to form ferritin, which is stored in the red bone marrow, liver, spleen, and intestinal mucosa 4.

The risk of adverse effects from food sources of iron is low. The U. S. Food and Drug Administration (FDA) has established a Reference Daily Intake (RDI) of 18 mg iron for adults and children 4 or more years of age as per 21CFR101.9, ( 5. RDIs are a set of dietary references for essential vitamins and minerals that are considered amounts sufficient to meet the daily requirements of healthy individuals. RDIs serve as the basis for calculating the percent daily value (%DV) amounts found on dietary supplement and food labels 5. Information is available on Recommended Dietary Allowances (RDAs) 6 by age and gender for the amount of iron that is recommended for daily intake 1, 2, 3.

This ingredient can be found in the following products in United States:


  1. Institute of Medicine (IOM). Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, D. C.: ISBN: 978-0-309-07290-8. National Academy Press (NAP), 2002. Accessed from or See Chapter 9, Iron -
  2. National Institutes of Health (NIH). Office of Dietary Supplements (ODS). U. S. Department of Health and Human Services. Fact Sheet for Health Professionals. Iron. Updated 9/20/2018. Accessed 10/12/18. Accessed from
  3. Kohn J. Iron. Academy of Nutrition and Dietetics. Published 12/14/2017. Retrieved on 10/12/2018. Accessed from
  4. U.S. National Library of Medicine (NLM). National Institutes of Health (NIH). National Center for Biotechnology Information. Compound PubChem Open Chemistry database. Compound Summary for CID 24978524. Iron gluconate.
  5. Food and Drug Administration (FDA). Code of Federal Regulations (CFR). Title 21. CFR21. Part 101.9. Nutrition labeling of food. Last updated 9/4/2018. Accessed on 10/12/2018. Accessed from
  6. National Institutes of Health (NIH). Office of Dietary Supplements (ODS). U. S. Department of Health and Human Services (HHS). Nutrition Recommendations: Dietary Reference Intakes (DRI). Accessed 6/19/2019. DRI Activities Update available: