Iron Supplementation in CF - Part 2

In the first part of this article series, we highlighted what causes iron deficiency in people with cystic fibrosis, and the various iron supplements available. This section will outline how to choose the best iron supplement for you, and what to expect during treatment.

Factors to consider when selecting iron

There are several factors to consider when selecting the best iron. The choice can be overwhelming. With so many options available, it is important that these factors are considered on an individual basis:¹

• Formulation - ferrous sulfate is available in a liquid formulation, which is a good option for people who cannot swallow pills or for young children.¹ For people who are vegan, Feramax, a polysaccharide type of iron, contains no animal by-products. It can be purchased in a powder or capsule formulation.²
• Cost - For most people, an inexpensive iron can be tried first. Heme iron (i.e. Proferrin) is derived from animal sources and tends to be the most expensive because it absorbs better. It is usually also better tolerated. Ferrous sulfate, gluconate, and fumarate, tend to be the cheapest.
• Side effects - people who are more sensitive to side effects such as stomach upset and nausea should consider a heme or polysaccharide iron.
• Absorption - absorption of iron depends on many factors, such as the type of iron, the dose, one’s diet, iron stores, and stomach acidity. In general, heme iron absorbs the best.³
• Diet - diets high in meat, poultry, fish, nuts, and grains are rich in iron. People who consume a lot of these foods may need to take less iron.⁴

How should iron be taken?

In general, iron should be taken on an empty stomach to enhance absorption. Specifically, non-heme irons should be administered on an empty stomach with water or orange juice.⁵

Side effects

There are many side effects of iron, but it is important to note that most of them improve with time and are dependent on dose.¹

• Constipation/diarrhea - more people experience constipation than diarrhea.
• Stomach pain/nausea
• Dark stools - this side effect does not get better over time.
• Teeth staining - liquid formulations may stain teeth. Drinking through a straw may help reduce staining.⁶

What if I can’t tolerate iron?

There are various avenues that may be tried. You can start with a lower dose and slowly work your way to a higher dose, or perhaps try a different type of iron. To minimize stomach irritation, the iron can be taken with food or at bedtime. If you choose to take non-heme iron with food, always avoid taking it with tea, coffee, milk, eggs, and cereals. This is because the non-heme iron will bind with these foods and form a complex that prevents full absorption.⁵

Duration of iron supplementation

The duration of iron supplementation depends on the severity of iron deficiency. In general, the key is to treat for an additional 3 months once iron deficiency has been corrected.⁷

Interactions with medications

It is best to avoid taking antacids and calcium supplements at the same time as iron; space these out by 2 hours at a minimum. In addition, it may be a good idea to temporarily stop iron supplementation if you are a tetracycline class of antibiotics. Always talk to your doctor before adding or changing medications and/or supplements.

Are or a loved one with cystic fibrosis taking an iron supplement? Share your experiences below!