How many mg of iron bisglycinate is equal to 65 mg elemental iron?
Oral iron supplements are commonly used to prevent and treat iron deficiency. There are various forms of iron available, including:
- Ferrous sulfate
- Ferrous gluconate
- Ferric sulfate
- Ferric citrate
- Ferrous bisglycinate chelate
Iron supplements are associated with common side effects, such as:
- Abdominal pain
Out of the many supplemental forms of iron, ferrous bisglycinate chelate may have a better side effect profile and better absorption.
Ferrous Bisglycinate Chelate
Ferrous bisglycinate chelate is a patented chelated form of iron by Albion, and is a ferrous (i.e. 'iron') cation coupled to two glycine molecules. The proprietary name for the iron is 'Ferrochel'.
It is promoted as having improved absorption and tolerability compared to other iron forms (e.g. ferrous sulfate). Additionally, it is thought to have less drug interactions when compared to other forms of iron. Multiple studies support these characteristics.
Most supplements that use ferrous bisglycinate chelate to provide elemental iron don't list the total amount included in the product. They generally just list the total 'elemental iron'. Below is an example for a popular product that contains Ferrochel (ferrous bisglycinate chelate) iron:
While many forms of iron will break apart in the GI tract, ferrous bisglycinate chelate does not (1). This may be part of the reason it is generally better tolerated than other forms of iron.
Additionally, ferrous bisglycinate chelate is thought to have better absorption and less drug interactions than most other forms of iron as it doesn't form insoluble compounds as readily (2, 3) with other drugs/compounds.
Ferrous Bisglycinate Chelate Vs. Ferrous Sulfate
Although you could compare two products for their elemental iron content (ferrous sulfate vs. ferrous bisglycinate chelate in this case), it is difficult as there are significant variations with absorption, even when the same amount of elemental iron is provided.
Multiple studies have shown that lower doses of ferrous bisglycinate chelate can provide similar effects to higher doses of ferrous sulfate.
For example, one study concluded the following:
"Our results showed that 90 days of supplementation with 30 mg/day of elemental iron as either ferrous sulfate or iron bis-glycinate chelate had a positive effect on raising ferritin concentration in school-age children with low iron stores. This effect was seen one week post-supplementation and was still present 6 months after supplementation. Furthermore, the bis-glycinate chelate compound was more efficient for maintaining higher ferritin concentration 6 months after supplementation than ferrous sulfate".
In other words, for the study referenced above, even though ferrous sulfate and ferrous bisglycinate chelate were given in amounts to equal the same amount of elemental iron, ferrous bisglycinate chelate was more efficient in raising iron levels in the body.
Another, similar study, tested the effectiveness of ferrous bisglycinate [25 mg elemental iron] to ferrous sulfate [50 mg elemental iron]. They concluded the following:
"In the prevention of ID [iron deficiency] and IDA [iron deficiency anemia], ferrous bisglycinate [25 mg elemental iron] was not inferior to ferrous sulfate [50 mg elemental iron]. Ferrous bisglycinate in a low dose of 25 mg iron/day appears to be adequate to prevent IDA in more than 95% of Danish women during pregnancy and postpartum."
Even using ferrous sulfate in an amount that provided double the amount of elemental iron, it was similar in effect to a low dose of ferrous bisglycinate chelate.
To address your question specifically, based on product label for supplements that list the total amount ferrous bisglycinate chelate (Now Foods Iron Complex is pictured below), 158 mg of Ferrochel (ferrous bisglycinate chelate) contains 27 mg of elemental iron.
Therefore, 380 mg of ferrous bisglycinate chelate would be around 65 mg of elemental iron. As discussed above though, ferrous bisglycinate chelate has different absorption properties than ferrous sulfate and studies show you need less [even in equivalent amounts of elemental iron] to have similar effects on the body.
If you are looking to supplement with iron, be sure to speak with your doctor regarding an appropriate form of iron. It is just important to know that all forms of iron aren't created equal, even those that provide the same amount of elemental iron.