All About Iron!

As common as anemia is, it is also quite confusing because there are so many different types that can arise from various causes!  Because iron deficiency anemia is one of the most common health disorders worldwide1, we decided to focus this article on this specific type.  Here is a very common scenario that we’re sure many of you can relate to. You are told by your doctor that you have low iron and should start taking iron supplements.  You then wander aimlessly throughout the pharmacy aisles and don’t see anything that says iron on it! You finally stumble upon your pharmacist who greets you with a warm smile and is happy to show you that they are kept behind the counter of the pharmacy.  So here it is – the explanation of the numerous iron products kept behind the pharmacy available to you from the convenience of your own home (and with a smile).  Make sure to read to the bottom because we will advise on some natural sources of iron because we know the pills can be hard on the stomach!

What can cause iron deficiency anemia?

Anemia occurs because there are not enough healthy red blood cells to carry oxygen.  The oxygen is transported on a structure called heme which is part of the red blood cell and contains the iron.  This is why iron is so essential – it’s at the core of the heme structure! Iron is needed so that the body can make red blood cells (hemoglobin). Many situations can cause iron deficiency anemia, such as a blood loss (through menstruation or frequent blood donation), poor diet, nutrient demands from pregnancy and breastfeeding, digestive conditions (Crohn’s or parts removed from the small intestine) and even specific drugs1,2,3.

The most commonly used supplements (iron gluconate, iron sulfate and iron fumarate) 

Iron gluconate, sulfate or fumarate are oral iron salts and most often recommended in patients that require iron supplements.  The differences between these forms are the amount of elemental iron in each 300 mg tablet.  Starting from least to greatest, the order is ferrous gluconate, ferrous sulfate and ferrous fumarate respectively.   For a lot of people, these ferrous salts cause a lot of intolerable side effects such as constipation, diarrhea and stomach pain2.  Because there are so many different foods and medications that can inhibit iron salt absorption, it is always recommended to try and take them on an empty stomach if possible.   Some foods that inhibit the absorption are coffee, tea, milk, dietary fiber and a multivitamin1.  However, vitamin C and acidic foods can help enhance the absorption1 – so taking iron with a glass of orange juice may do the trick!

Other types of iron on the market

Besides the basic iron salts, there are other types of irons supplements on the market.  What differs between these newer agents and basic iron salts is the structure of the iron being absorbed and where in the body it is absorbed.

FeraMax® – This supplement is made up of what is called a polysaccharide-iron complex.  In order to not get too technical here, it’s best just to understand it to be a different type of iron complex which is not a salt form.  This polysaccharide form has been around for a long time and has shown a good safety profile overtime4.    Feramax® has been shown to have less stomach side effects because of its special coating.  This coating prevents FeraMax® from coming into contact with the stomach and allows it to start to dissolve when it passes the duodenum (small intestine). This is also why it can be taken with or without food.

Proferrin® – this supplement contains a heme-iron polypeptide.  Again, this is a completely different type of iron structure.   It is derived from bovine (pertains to cattle or buffalo); therefore, it is made from an animal.  Heme iron is naturally found in foods such as meat, poultry and fish and is absorbed better in the body than a non-heme iron (plant based iron).  The receptor for heme iron is in the small intestine and is different from the receptor for non-heme iron.  Because of this, it is thought to be more easily absorbed (therefore a smaller dose is required) and can also be taken without regard to food.  In addition, it may also have less stomach side effects than the iron salts 6.

How much iron should I take?

Approximately only 10% of iron from the salt forms (gluconate, sulfate and fumarate) is absorbed in the body1.   The amount absorbed by FeraMa®x and Proferrin® may be greater due to their structure and where they are absorbed ; therefore, they can be dosed less frequently.  A common approach is approximately 150 – 200 mg of elemental iron per day for 4 weeks (a total of 500 – 800 mg of iron)1.  This is just one suggested method as blood levels should be taken in order to make sure iron levels are restored.  The amount and duration will also be different depending on how severe the anemia is and how much iron you are able to take.  So make sure you talk to a health professional about your individual situation.  Taking this much iron can sometimes cause uncomfortable side effects such as nausea, constipation and diarrhea.  If you experience these side effects it’s best to try a different formulation to see if it is more tolerable for you.

Here is a handy summarized chart for you! 

Iron Salt Elemental Iron (per 300 mg tablet) Usual recommended Dose How to take it
Ferrous gluconate 35 mg 1-3 tabs; 2-3 times a day Empty stomach (glass of orange juice)
Ferrous sulfate 60 mg 1 tab; 3 times a day Empty stomach (glass of orange juice)
Ferrous fumarate 100 mg 1 tab; 2 times a day Empty stomach (glass of orange juice)
FeraMax® 150 mg 1 caps; 1 time a day With or without food
Proferrin® 11 mg 1 tab; 1-3 times a day With or without food


The importance of iron in the diet

About 1-2 g of iron is required in a diet to balance the daily losses of iron.  The amount is a lot higher if you are treating iron deficiency anemia and it can take a lot longer to treat if supplements are not used.  Dietary iron from animal sources is rich in heme iron and is therefore better absorbed.  These can include liver, lean red meats, oysters, clams, tuna, salmon, sardines and shrimp.  Non-heme iron is found in cereals, egg yolk and green leafy vegetables and is not well absorbed.  For all those tea drinkers – tea inhibits iron absorption so if you are iron-deficient you should wait 1-2 hours after your meal before drinking tea! 1,5.

Bottom line

Taking iron supplements is a faster and more efficient method than treating iron deficiency with diet alone.  However, it is important that there is enough iron in your diet to maintain healthy iron levels.  All iron supplements can work in treating iron deficiency anemia.  Unfortunately there are no clear head-to-head trials to determine if one type of iron works better than another.  If you are experiencing intolerable side effects from the iron salts (gluconate, sulfate and fumarate) you may benefit from a formulation like Feramax® or Proferrin® which have shown to have less stomach side effects and can be taken with or without food!

The Health Aisle Team



  1. Alleyne M, Horne M and Miller J.  Individualized treatment for iron-deficiency anemia in adults (2008). The American Journal of Medicine. 121: 943-948.
  2. Bereman R and Berg K. The structure, size and solution chemistry of a polysaccharide iron complex (1989).  Inorganica Chemica Acta; 155: 183-189.
  3. Piccinni L and Ricciotti M.  Therapeutic effectiveness of an iron-polysaccharide complex in comparison with iron fumarate in the treatment of iron deficiency anaemias (1982). Pan Med. 24: 213 – 220.  
  4. Sanders JF. Clinical response to iron-polysaccharide complex in geriatric patients with iron-deficiency anemia (1968). 67(11): 726-7. 
  5. Patterson AJ, Brown WJ, Roberts DC et al. Dietary treatment of iron deficiency anemia in women of childbearing age (2001).  Am J Clin Nutr. 74(5): 650-656.
  6. Barraclough K, Noble E, Leary D et al.  Rationale and design of the oral HEMe iron polypeptide Against Treatment with Oral Controlled Release Iron Tablets trial for the correction of anaemia in peritoneal dialysis patients(HEMATOCRIT trial) (2009).  BMC Nephrology. 10: 20.