We here at Full Circle (my lovely wife Shelly and I) would wholeheartedly agree that most common complaint among our customers is the numerous side-effects associated with over-the-counter and prescription iron supplements. Often, side effects involve constipation, bloating, cramping and occasionally pain. It’s typically not long before the symptoms become intolerable enough to take action. Unabsorbed iron accumulates in the intestine and has an inflammatory effect that leads to the majority of side-effects. Choosing an iron that absorbs well means less iron lingering in the intestines to cause problems, and side-effects can be minimized or avoided completely. Are you ready for a ride on the iron information rocket ship? Here we go! 

The problem with traditional iron supplements is straightforward, and surprisingly hasn’t been addressed by the majority of iron manufacturers despite being an ongoing and troublesome issue. The key areas that determine how well or poorly made an iron supplement is boils down to:

  • dosage per serving
  • which iron chelate is used
  • complementary nutrients
  • dissolution ability of the supplement
  • whether it is taken on a full or empty stomach

None of these factors can be viewed in isolation. The best iron supplements address all of these issues, or strike a reasonable balance. Consumers want iron that is inexpensive, absorbs well, improves iron levels and symptoms, and is without side-effects. Is that too much to ask?

Let’s take a look at the dosage per serving. This is the amount of iron contained in a single capsule, tablet, teaspoon etc. The lower the iron dose, the better the iron absorption, and the lower the risk of side-effects. Iron with a dosage of 5mg per serving will absorb far better than a dose of 100mg (when expressed as % of absorption). The problem is, you may need a high dose! In these cases, you will always be better off taking a lower dose multiple times per day; anything else is bound to cause you digestive upset.

The chemical state of iron is also important. Iron comes in a variety of forms including iron sulfate, iron gluconate, iron fumarate, iron citrate, iron bisglycinate and iron bound to hemoglobin. The chemical state of iron affects how well it will be absorbed across the intestinal barrier. Iron is notoriously difficult to absorb, with most iron supplements topping out at 10% absorption per dose. More bioavailable forms of iron are typically absorbed 3-4x better than most inorganic forms of iron which are commonly found in the marketplace. Most importantly, the rate of iron absorption for most iron supplements is largely regulated by the degree of iron deficiency within the body itself.

Complementary nutrients such as vitamin C, B12 and folic are occasionally added to iron supplements to improve absorption and address other potential sources of anemia. While vitamin C has been shown to drastically improve the bioavailability of many forms of iron, it’s important to ensure that you are taking both the correct kind of vitamin C, as well as the appropriate dosage.

There is a misconception that iron in liquid format is universally superior to iron found in capsules or tablets; however that couldn’t be further from the truth. Liquid iron supplements are readily digestible, but not necessarily more absorbable. When evaluating iron products, we tend to put emphasis on both the form of iron and the dose per serving, as iron liquids, tablets and capsules all have good solubility. Just because iron is found in a liquid supplement doesn’t mean that the dose, or type of iron will be ideal.

As mentioned previously, absorbing iron is challenging and a number of dietary factors commonly found in food such as phytic acid, oxalic acid, tannic acid, soluble fibres (plant heavy diets basically), and minerals such as calcium, magnesium and zinc actually interfere with iron absorption. Developing a good timing strategy that involves taking iron supplements away from meals, and (potentially) other supplements to maximize absorption can have a profound effect on iron absorption.

Our general recommendations are typically to use an iron dose between 20-40mg per serving, typically either in the form of iron bisglycinate or (even better), Heme Iron Polypeptide. Combining a highly absorbable form of iron with high doses of pure ascorbic acid (vitamin C) in the 500mg – 2000mg range will offer a tremendous improvement to most iron supplements, just be sure to use pure ascorbic acid as mineral ascorbates (such as calcium ascorbate) have the potential to worsen iron absorption. Lastly, taking them on an empty stomach will certainly improve absorption, though a small percentage of people notice a bit of digestive upset in this manner. With over 10 years of experience with patients and clients using this general iron strategy, we’ve had less than half a dozen people report any sign of digestive upset.

Whew! That’s a lot of talk about iron isn’t it? As with everything related to nutrition and health, there is never a one-size-fits-all approach. Balancing dose, form, timing, and complementary nutrients will maximize your iron absorption, eliminate digestive upset, and get you back to feeling fit as a fiddle sooner than later. If you’d like to drop by our dispensary we’d be happy to help you pick out an iron that’s just right for you. Let us take the marketing out of health, and stick with what works.