Not getting enough iron slowly drains your energy. In this blog post I will help you understand what causes low iron but even more importantly – how to rebuild your iron stores and get your energy back.

Getting enough iron can be really tricky even if you are using supplements so make sure you pay special attention to the section on maximizing iron intake where I outline how to get the most from your food and supplements.

What Causes Low Iron


Everyone loses a bit of iron everyday. If you aren’t getting enough iron in your diet, your iron reserves will fall slowly. If they keep falling, you may develop an iron deficiency. If they fall even further, you won’t have enough iron to make red blood cells. This is called iron deficiency anemia.

Iron deficiency is very common for women until we reach menopause because we lose extra iron every month during our periods. If you have regular cycles, your doctor should suggest testing iron whenever you run any other blood tests but reality is – a lot of the time we need to ask for it to be tested.

Serum ferritin is usually used as the primary test for low iron and, while it’s not clear from the research, many experts suggest the ideal range of serum ferritin is 40 to 70 ng/ml. You’ll see the reference range on your test results runs from about 20 to 200 ng /ml but for health and longevity purposes you may not want it to be too high either.

Having too much iron is associated with accelerated aging, inflammation and many chronic diseases like cardiovascular and neurodegenerative diseases. That’s why it’s important to get tested before you start supplementing with iron.


Reasons for low iron include:


  • Insufficient dietary intake of iron (even more likely if you follow a low calorie diet and/or don’t eat meat)
  • Consuming too many foods and beverages that block iron absorption
  • Heavy periods and/or prolonged periods
  • Pregnancy and childbirth
  • Digestive system problems that prevent absorption (for example, iron deficiency is very common in people with inflammatory bowel disease)
  • Strenuous exercise that causes gastrointestinal bleeding, excessive sweating or being a runner (because foot strike can cause iron loss)
  • Regularly engaging in intense exercise
  • Chronic blood loss (for example, from endometriosis or fibroids, which require a great amount of blood).



Symptoms of Iron Deficiency


If you are iron deficient it’s really important to get on top of it because having low iron feels terrible!

If you’ve ever been really low in iron you know how terrible it feels. When you start running low on iron, you need to get on top of it to prevent it from progressing to anemia and full on debilitating fatigue. Believe me, I’ve been there, and it sucks. Don’t let it progress to that point.


Common symptoms of low iron:


  • Fatigue
  • Lack of energy and motivation
  • Inability to focus or brain fog
  • Headache or ringing ears
  • Shortness of breath
  • Nausea
  • Pale appearance
  • Rapid heart beat
  • Cold hands and feet
  • Low body temperature
  • Restless legs
  • Brittle hair and nails
  • Depression or anxiety.



Getting Enough Iron From Food


While you may be able to maintain iron stores through diet, it’s probably impossible to rebuild them from food alone once they are low.


You get two different types of iron from food – heme and non-heme. Heme iron is found in meat, fish and poultry and non-heme iron is found in plants. Your body is better able to absorb and use heme iron than it is non-heme iron. It’s estimated that you absorb 15-35% of heme iron and 2-20% of non-heme iron.

If you don’t eat meat, it’s recommended that you consume twice as much iron since non-heme iron isn’t absorbed as well. Consuming vitamin C with your non-heme iron sources will substantially increase the amount of iron absorbed (and in the next section I have even more tips for you on maximizing your iron intake).

Interestingly, if you are iron deficient you will be more efficient at absorbing iron from all sources as compared to someone with normal iron levels. However, your body isn’t very good at absorbing iron so even if you are consuming the recommended intake of 18mg of iron daily, you will only absorb a few grams. In fact, absorption rarely increases to more than 6g per day unless supplemental iron is added!


Foods high in iron (approximate values given):


  • Lean trimmed beef (100g) =  3mg
  • Chicken thigh meat (100g) = 1.3mg
  • Oysters (6 medium) = 5mg
  • Mussels (100g) = 7mg
  • Lentils (1/2 cup cooked) = 3.3mg
  • Black beans (1/2 cup cooked) = 1.3mg
  • Black-eyed peas (1/2 cup cooked) = 2.15mg
  • Fortified protein powders and bars = depends on brand but may have 20-25% of daily intake


Given the small amount of iron in food and the fact that we don’t absorb that much of it, you can understand why it’s easy to start running low. It will also be difficult to rebuild iron stores from food alone because:

  • Unless we eat multiple red meat meals daily in the absence of other foods and beverages that will block absorption, we won’t consume enough iron to rebuild iron stores.
  • Many foods that are high in iron (ie. spinach, chocolate) contain compounds that will block iron absorption (ie. oxalates).
  • There are many foods and beverages that inhibit iron absorption.
  • If you are restricting calories, it will be even more difficult to consume enough iron rich foods.
  • Some foods that are high in iron are also high in calories (ie. Dried fruit contains iron but the serving sizes are often 1/2 cup for just over 1g of non-heme iron.).


Maximizing Iron Intake


For reasons you’ll read about in the following section, I’m not a fan of using the prescription iron pills so I’ve had to work hard to boost my iron levels from a combo of food and gentler iron supplements.

We all know that coffee and tea block iron absorption but there are many other foods that interact with iron. In fact, it can make your head spin when you are trying to figure out how to optimally time your iron intake. So in this section, I’ll give you some of the rules I’ve come up with to maximize iron intake:

  • Tea and coffee will substantially block iron absorption. Avoid drinking 1-2 hours before and after an iron-rich meal and iron supplements.
  • Dairy and calcium supplements will block iron absorption so avoid them before and after iron-rich meals and iron supplements.
  • Magnesium may decrease non-heme iron absorption and absorption from supplements so take magnesium away from iron-rich meals and iron supplements.
  • Zinc competes with iron for absorption so take zinc at a different time than iron. Also, supplementing with iron may decrease zinc levels so if you’ve been using supplements for some time, you may want to take a zinc test (readily available on many websites that sell health supplements).
  • Since certain minerals compete with iron for absorption and iron can block absorption of other minerals as well, take your multivitamin at a different time than iron supplements. Also do not use a multivitamin that contains iron.
  • Substances called phytates, found in grains, beans, seeds and nuts, will reduce iron absorption (as well as other minerals such as zinc, calcium and magnesium). You can reduce phytates by soaking your grains overnight and rinsing them several times before cooking but it’s probably wise to consume grains away from your main iron sources. Fermenting and sprouting grains also helps.
  • If you regularly eat beef stir fry or black bean bowls and rely on them as an iron source, you’ll reduce phytates by eating white rice instead of brown.
  • Oxalates, found in foods such as spinach, kale, beets, chocolate, and strawberries, can block iron absorption. That’s why spinach, although high in iron, isn’t a good source of iron.
  • Ascorbic acid/vitamin C is the most effective enhancer of non-heme iron absorption. Consuming vitamin C supplements or foods high in vitamin C with iron rich meals will increase the amount of iron you can absorb from non-heme iron sources and supplements, and may negate some of the iron inhibition from phytates and oxalates.
  • Eating some meat (heme iron) or fish with non-heme iron sources will also increase the absorption of iron from that meal. Heme iron is less affected by other foods eaten in the same meal.
  • Egg yolks contain a protein called phosvitin that binds iron and renders it unavailable to the body. Consuming an egg with a meal or supplement will substantially reduce the amount of iron absorbed.
  • Some research suggests that you should divide your dose of iron throughout the day rather than taking it all at once. This will also help reduce any stomach problems you have from supplements.


Choosing A Good Iron Supplement




Many women report negative effects from taking prescription iron tablets – with main complaints being stomach ache, nausea and constipation. One of the main problems with prescription iron tablets, which usually contain 325mg of ferrous sulfate (65mg of elemental iron), is the size. Generally, the larger the dose of iron the more side effects you’ll experience.

If you research iron supplements, you’ll quickly find out that they are “toxic” to your body. In fact, my doctor told me this just the other day as he was writing me a prescription for ferrous sulfate (one that I have no intention on filling but it was pointless arguing with him).

So even though your doctor knows that iron is toxic, they still prescribe it in large dose tablets that upset our stomachs. In fact, if you are low in iron, your doctor will probably tell you that ferrous sulfate is the only way to restore iron levels which isn’t exactly true. Ferrous sulfate will probably raise iron levels faster than other smaller dose supplements but if it hurts your stomach, you aren’t going to take it regularly. So that’s not going to work anyway.

The recommended daily intake of elemental iron is 150-200mg per day for iron-deficient patients. That would mean taking three of the prescription ferrous sulfate tablets daily. Taking just one of the ferrous sulfate tablets makes me feel terribly nauseous so I can’t imagine taking three per day!

It’s estimated that, assuming no problems with absorption, you’d need to take this much iron for four weeks to correct a moderate deficiency. If you have a severe deficiency it make take months to correct. Given the side effects of ferrous sulfate tablets, many people never follow through with this regime.

If your iron is low, you can’t just quit supplementing or it will get even lower. Believe me, I’ve done that and it leads to anemia and feels awful. The good news is that there are “gentler” forms of iron supplements.

Some studies suggest that other forms of iron – such as carbonyl iron and iron bisglycinate – are less toxic and lead to less gastric side effects. The challenge with these supplements is that they contain much less iron than the prescription iron tablets. Therefore you will need to take more of them and take them for longer than the prescription tablets.



One of the most common gentler forms of iron goes by the brand name of Ferrochel®. I’ve experimented with many different forms of gentler iron and this is the only one that seems to make a difference. In fact, within a week of supplementing, many of my clients have noticed an improvement in energy.

You’ll find Ferrochel® in many iron supplements, including the one I recommend to clients. The following is a diagram showing how Ferrochel® is easier on the stomach as compared to other supplements using iron salts.


Photo Source: Albion

I have taken up to six capsules per day after heavy periods with no stomach problems. Six per day will be about 160mg of iron so it’s getting into the range recommended by doctors to reverse iron deficiency.

I have also seen improved ferritin levels with my clients after taking this supplement even with as little as one per day.



The Link Between Heavy Periods and Low Iron


A heavy period is usually defined as losing more than 80 ml of blood per period. For some women a heavy period could mean as much as 1 cup of blood lost.

1 cup of blood lost is 100-125 mg of iron lost.

That’s a lot of iron! If your basic needs are already 18mg per day then you need to add an extra 25-30mg per day for at least 5 days after your period to make up the shortfall. Remember your body doesn’t absorb all the iron from food or supplements (although you do absorb more when your iron is low), so if you are trying to replenish after a heavy period you’ll need your intake to come to more than 100-125 over the following week or so plus the 18g per day for your daily needs. You can see how difficult it will be to get this from food alone.

If you don’t replace the iron lost your iron stores will keep dropping with each heavy period. This is problematic because not only do heavy period deplete iron stores but having low iron causes heavy periods.

As you rebuild your iron, your periods will probably start getting lighter – resulting in less iron lost every month!


The Link Between Low Iron and Thyroid


There is a link between low iron and thyroid function although more research is needed to understand this relationship. Normal thyroid function depends on the presence of many trace elements, including iodine, selenium, zinc and iron.

Studies have found that iron deficiency impairs thyroid metabolism, and that iron deficiency can cause hypothyroidism and vice versa. For example, low iron levels can increase circulating concentrations of TSH (thyroid stimulating hormone). Hypothyroidism may also lead to low iron levels due to poor gut absorption as a result of decreased levels of digestive acids/ enzymes or due to associated autoimmune conditions like celiac disease.

Iron treatment for women with subclinical hypothyroidism has been shown to create a small increase in T4 and a decrease in TSH (which is a good thing). If you are iron deficient with a thyroid condition, it’s essential that you work with your doctor to address your deficiency and see how your thyroid responds.


Final Takeaways


It’s really important to get on top of your iron levels so that you can feel your best and prevent more serious problems like anemia from developing. If you have conditions that require more iron – like heavy periods or digestive conditions – then you are probably going to need to use a supplement (but only after you’ve had a blood test and identified a need for it because too much iron isn’t good for you either).

Making sure you absorb enough iron from your food and supplements is tricky so go back to the section on maximizing iron intake if needed and figure out how to best time your iron-rich meals and supplements. If you have any questions, I’d love to hear from you!


You may also be interested in these articles:


Benefits Of Curcumin – A Powerhouse For Women’s Health

Rescue Yourself With Magnesium


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