What you need to know about iron absorption from food and supplements

So many of the mums I work with either have a history of low iron and/or anaemia, still have low iron levels, or at the very best suboptimal iron levels.

Pregnancy and birth are very taxing on the body’s iron levels and unless we’re proactive about maintaining optimal levels before, during and after pregnancy, the numbers often steadily decline. At the same time, the symptoms of low iron or iron deficiency progressively increase.

These include ongoing fatigue, headaches, brain fog, hair loss, shortness of breath, feeling lightheaded, ‘spacey’, forgetful and/or having difficulty concentrating. You can also have pale skin and sclera (the whites of the eye) and weak, brittle nails.

If you’re working on increasing your levels through your diet and/or supplements, it’s important to understand some key factors that are involved in how our body absorbs that iron. 

It's not as simple as ‘what I put into my mouth’ will ‘get into my bloodstream/body.’

For if you’re trying to increase your iron levels, or even maintain them at an optimal level, you need to consider more than just the iron. Here's what's also involved.

STOMACH ACID

You need optimal stomach acid to release the iron from food/supplement. Without this first step working properly, you’re already on the back foot. If you’re taking antacids or protein-pump inhibitors for ‘gastric reflux’ you’ll find iron and ALL your mineral absorption will be affected. That’s another story for another time.

If you’ve had surgery/gastric sleeve, you’re likely have ongoing gut and nutritional issues as a result of this procedure. Again, another discussion for another time.

CO-FACTORS

Nothing works alone in the body, it’s always a team effort. To optimally utilise the iron you’re having (either through food and/or supplements) your body needs co-factors. They are part of the team responsible for absorption, transport and use of iron.

This includes Vitamin A and copper.

I’ve seen stubborn low iron levels get a noticeable lift by adding preformed, natural Vitamin A (also known as retinol) and copper into the diet through something like beef liver. This can be in capsule or powder form, or used in cooking.

Liver is rich in both retinol and copper, as well as containing a small amount of iron. If I'm actively trying to raise a mama's iron levels, I may use beef liver (often in a convenient capsule form) alongside a good quality iron supplement.

If your diet is ‘low-fat’, vegetarian or vegan, or you’re not using any organ meats (or supplements) you may not be getting adequate Vitamin A. This is a fat-soluble vitamin.

GUT FUNCTION

If you have ongoing gut issues such as coeliac disease, ulcerative colitis or are taking medication like NSAIDS, your absorption (of many nutrients, including iron) via the intestinal wall will also be affected.

If you have gallbladder issues, you’re going to have fat digestion issues. This can affect how well you’re digesting and absorbing Vitamin A.

If you’ve had your gallbladder removed, it’s not uncommon to have some ongoing digestive and gut issues.

If you have gut dysbiosis (an imbalance in your gut microbiome) you can also have issues absorbing your iron. So, just another reason to sort your gut out!

If you have a thyroid issue (either underactive or overactive) your digestive function/gastric juices/digestive enzymes can also be affected. This then affects how you're able to digest your food, and therefore absorb your nutrients; including iron. It’s estimated up to 40% of those with Hashimoto’s hypothyroidism have low stomach acid.

You can read more about the relationship between thyroid gland function and iron here.

HEPCIDIN

Have you heard of hepcidin? It’s our iron regulatory hormone. Some call it the 'iron hormone'. It plays a very important role in the body around how and when we absorb iron.

It's produced in the liver and works to control the entry of iron into our bloodstream from our diet, our iron stores, and the iron that is recycled from 'old' red blood cells.

Hepcidin essentially helps protect us from taking in too much iron. This is a good thing as iron can be inflammatory and toxic to the body.

Hepcidin also displays a diurnal variation. This means its concentration is lowest in the early morning and steadily increases throughout the day, before declining during the evening hours.

So what this means is, if you're taking an iron supplement in the morning (or perhaps last thing at night) this will often result in more of it being absorbed, because the potential blocking effects of hepcidin are at their lowest. This is a good thing if you’re working to raise your iron levels.

These blocking effects of hepcidin can also increase if you’re taking a high dose of iron, and/or you’re taking it too often.

For example: Maltofer and Ferrograd C contain around 100mg iron per dose. This is a very high dose, but in some ways its understandable as the form of iron they contain is so poorly absorbed! Taking this dose daily will trigger a high rise in hepcidin. Which in turn reduces the ability for the iron to be absorbed!

This is a real issue for high-dose iron supplements ie. the more iron you take, the more you’ll trigger a rise in hepcidin, the less iron you’ll be able to absorb. This is often why so many women don’t respond well to these supplements and their iron deficiency issue perpetuates!

One hepcidin is triggered to rise, it will stay high for around 24 hours. As a result, it then decreases iron absorption from both our food and/or supplements taken later on the same or next day!

Not surprisingly, I don’t recommend these forms of iron. There are much better ones to choose from eg. iron biglycinate.

Depending on the individual case, I may suggest women take their iron supplement every 2nd day. Some studies have shown this may increase the iron absorption by >35-50%. Now that you know all about hepcidin, this should make a lot of sense!

TIMING

What you take with or close to your iron supplement also matters. Tea and coffee consumed at the same time as iron supplements or with iron-rich meals will inhibit absorption. This is due to the tannins and the polyphenols

It’s also best to avoid taking dairy products with or close to iron as the high calcium content will compete with iron for absorption.

If you’re also taking other minerals in supplement form (eg. zinc) I suggest leaving a good 4 hours between dosing.

FINAL THOUGHTS

Whenever I’m supporting a mother’s low iron levels, I’m always asking and investigating WHY she has low iron in the first place.

Sometimes it’s a cumulative issue that started in her first - or last - pregnancy! Sometimes her levels simply weren’t checked or her results were interpreted as ‘fine’ when actually, she was heading in the wrong direction and no action was taken.

Sometimes, it’s this plus a lack of dietary iron. Sometimes, it’s this and the result of a decent bleed at the birth (>1 litre) followed by poorly absorbed iron supplements. Sometimes it’s her persistently heavy periods.

This is why it’s so important to take the time to understand a woman’s individual situation, do the right blood tests and interpret them through an ‘optimal’ lens, not just checking they’re ‘within range’. Then we address the driving factor/s behind her ‘low iron’ as well as work to get her levels up in the short term.