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If you have low iron levels, you may wonder which iron supplements are best for young athletes?  There are so many brands to choose from, which one will work the best and not cause side effects?  What is the right dose for your athlete?  Read this blog about everything you need to know to safely and effectively supplement your athlete with an iron supplement.

Do You Need an Iron Supplement?

Finding and fixing iron deficiency in athletes boosts stamina and enables them to perform at their best.  Know your iron levels and talk to a doctor, dietitian, or pharmacist about whether your levels can benefit from an iron supplement. If you are not sure whether your athlete has low or optimal iron levels, you can compare your iron levels to the amounts listed in this blog Young Athletes Have Iron Deficiency and Not Just the Girls.  If you have iron deficiency, iron supplementation is much faster and more effective at boosting your iron levels, compared to eating iron rich foods.  For more information on boosting your iron intake from foods, see this blog How to Get More Iron from Your Diet.

How Much Iron Is Recommended?

The dose of an iron supplement is very important and should be discussed with your doctor.  If you take too little, your iron levels will not improve and if you take too much you may experience unpleasant side effects.  The optimal dose will depend on the weight of the individual and the extent or level of iron deficiency.  The recommended dose of iron supplements is always referred to as the amount of elemental iron in the supplement.

What is Elemental Iron?

Iron supplements contain different amounts of elemental iron. When you choose a supplement, be sure to check the label to see how much elemental iron it contains. A greater amount of elemental iron means your body will absorb more iron.

Iron supplements generally contain one of three iron salts: iron sulphate, iron gluconate, and iron fumurate. The different molecular weights of the salts will have a different weight on the bottle for a similar dose.  You must compare mg of elemental iron in order to compare apples to apples, or iron to iron in this case.

Type Iron Salt Dose (mg) Elemental iron content (mg)
Ferrous sulphate 324 65
Ferrous gluconate 300 36
Ferrous fumurate 100 33

How Well do we Absorb Iron Supplements?

We only absorb about 10% of iron salts, so we will absorb about 10mg elemental iron when we take a dose of 100mg elemental iron from an iron salt.  Some iron supplements are made from heme iron, which is very well absorbed like Proferrin.  Heme iron supplements contain 11mg elemental iron, which is equivalent to a 110mg dose of another supplement made from an iron salt.

The recommended dose of iron supplements in children is:

  • 1-3mg of elemental iron per kg body weight for mild iron deficiency
  • 3-6mg of elemental iron per kg body weight for severe iron deficiency anemia.

A common dose prescribed to teens with iron deficiency is:

  • 100mg of elemental iron, every other day for optimal absorption and to minimize side effects.

The recommended dose of iron supplements for adults is:

  • 150mg of elemental iron, every other day for optimal absorption and to minimize side effects.

Can You Overdo Iron Supplements?

Taking too much iron can cause life threatening toxicity and organ damage.  It is not recommended to take iron supplements without first checking iron levels in your blood and speaking with your health care provider.

Talk to your health care provider before taking an iron supplement.

doctor holding an iron pill

When To Take Iron Supplements?

New research shows that we absorb our iron supplements best if we take a large dose every other day and only in the morning.  Instead of taking your supplement daily, take it on alternate-day schedules and take a single dose in the morning to increase iron absorption and reduce side effects. Thus, providing morning doses of 60–120 mg iron as a ferrous salt seems most effective.

Take your iron pill every other day, in the morning on an empty stomach.

teen girl taking a vitamin supplement with water

What are Side Effects of Iron Supplements?

Common side effects of iron supplements include nausea, constipation and black stools.  Side effects become more pronounced with higher doses and when iron is taken daily.

To limit the side effects of iron supplements, take them every other day.

Should I Take Iron Supplements with Vitamin C?

Despite its clear effect on absorption, taking vitamin C with iron supplements does not affect hemoglobin or ferritin levels or improve side effects of iron supplements. Clinical trials have proven that taking iron supplements with vitamin C does not improve iron status in adults with anemia. A 2020 RCT (n=440) concluded that iron supplements improve iron status (e.g. hemoglobin, ferritin) equally in adults with anemia whether they are administered with or without vitamin C.

Taking an iron supplement with vitamin C does not help your iron levels.

vitamin C myth

There are 3 types of iron supplements:

Among the tablet preparations, there are non-enteric coated pills and enteric-coated and prolonged-release formulations. Non-enteric coated iron tablets are most commonly used as initial treatment due to their lower cost. Delayed release and enteric-coated iron preparations have been advocated since they are better tolerated than the non-enteric coated tablets. However, they are less effective since they may contain less iron and their iron may not be released in the duodenum, where iron is absorbed.

  1. Iron salts like Fer-in-sol, Palafer and Ferapro.  Most effective and affordable option, but have stomach side effects.  Common side effects include constipation, black stool, and nausea.  Ferapro is unique because it contains amino acid glycine which prevents these side effects but it is more expensive than the first two.
  2. Polysaccharide Iron or Chelated Iron like Feramax and Sisu Gentle Iron.  Effective and well tolerated but they are more expensive.  Less/no side effects due to improved absorption.
  3. Heme iron like Proferrin, Optiferalpha, and Hemeboost.  Very effective, but very expensive.  Made of bovine hemoglobin.  No side effects due to improved absorption.

For a complete list of iron supplement brands, see this Iron Supplement Guide by Ontario Midwives.

Which Iron Supplement Should I take?

The first line of iron supplements are Palafer and Fer-in-sol because they are effective and affordable.  But if you have a history of constipation or upset stomach with these iron supplements, you can try Ferapro, Feramax or Gentle Iron, as these have fewer side effects.  If you have difficulty with these options, you may consider a heme iron supplement.  If you have any doubts, speak with your pharmacist or health care provider.