Overview
Iron deficiency is common and can affect energy levels, day-to-day functioning, and exercise performance. It often develops due to increased iron needs, blood loss, reduced absorption, or a combination of these factors. The most effective approach usually starts with confirming the deficiency through blood tests, then using a targeted supplement strategy to correct it, while also improving dietary intake and absorption habits to support longer-term maintenance.
Common Causes and Risk Factors of Iron Deficiency
Several groups face a higher risk of iron deficiency because their iron needs increase or their iron losses are higher. Menstruation is a major contributor, and pregnancy also increases iron requirements substantially. Any form of bleeding can also play a role, including gastrointestinal bleeding linked to inflammatory bowel disease.
Some athletes can also be at increased risk, particularly endurance athletes such as runners. Repeated impact from running may contribute to lower iron status in some people.
Absorption issues add another layer. Coeliac disease, particularly if it is not well managed, can reduce iron absorption. Inflammatory bowel disease can contribute through both bleeding and reduced absorption. In addition, a high intake of inhibitors such as tea or coffee may reduce iron absorption, especially when these are consumed around iron-rich meals or supplements.
Signs and Symptoms of Iron Deficiency
Iron deficiency often shows up through symptoms that can feel vague at first. Common complaints include tiredness, headaches, dizziness, and weakness. For people who train, low iron may also present as poorer exercise performance or shortness of breath during sessions. Because these symptoms overlap with many other issues, testing is important rather than relying on symptoms alone.
Testing for Iron Deficiency
The simplest way to check iron status involves a full blood count plus iron studies. Ferritin is the main marker used to assess iron stores. In many adults, ferritin levels below 30 micrograms per litre suggest low iron.
Other markers help confirm iron deficiency and clarify the picture. These can include transferrin, transferrin saturation, serum iron, and total iron binding capacity (TIBC). Looking at the full panel helps determine whether low iron stores explain the symptoms or whether inflammation may be affecting results.
Supplement Options
When the goal is to correct a deficiency efficiently, supplements often shift iron status more than food changes alone. Most iron supplements fall into two common forms: ferrous salts (Fe2+) such as Ferrograd C, and ferric forms such as iron polymaltose, such as Maltofer.
Iron infusion is another option that delivers iron intravenously. However, oral supplements remain a common first step when appropriate, particularly because they are accessible and can be effective when taken consistently.
Ferrograd C vs Maltofer and Side Effects
A common approach is to start with Ferrograd C because it is widely used and considered effective. However, gastrointestinal side effects are common with iron supplements. Constipation and nausea often occur, and dark stools are also normal for many people.
Even when a gentler form is considered, side effects can still occur. The difference often comes down to how severe the symptoms feel for the individual and whether changing the approach improves tolerance enough to stay consistent.
How to Manage Supplement Side Effects
Side effects are common, yet they are often manageable with simple strategies. For constipation, increasing fluids and fibre can help. If constipation becomes difficult, switching to a gentler form may be worth considering.
For nausea, taking the supplement at night can reduce how much it disrupts the day. Alternatively, taking it with a small snack may help some people tolerate it better.
Dosing frequency may also be an option for people who struggle with side effects. There is discussion around taking iron every second day rather than daily because the body produces hepcidin, a hormone that temporarily reduces iron absorption for about 24 hours after a dose. While it does not block absorption completely, alternate-day dosing may still help improve iron status while reducing side effects for some people.
Another practical approach is to consider using a lower dose or less frequent dosing when side effects become a barrier. A smaller amount may not correct deficiency as quickly, yet it can still be better than stopping completely, especially if consistency becomes achievable.
Liver and Spleen Supplements
Some people use liver or spleen-based supplements as an alternative. These can be nutrient dense overall, but the iron content is often low compared with standard iron supplements. In many cases, the iron amount may be one to three milligrams, whereas common iron supplements provide around 100 milligrams of elemental iron. That gap matters when correcting a deficiency.
Some outlier products provide higher amounts of heme iron, including supplements that combine organs such as spleen and liver and may reach 10+ milligrams. Even then, these products are not considered the gold standard for treating iron deficiency. They may be more relevant as a maintenance option for people whose iron is within the normal range and who want additional dietary support.
It is also worth noting that fewer side effects with organ-based supplements may reflect the much lower iron dose. In other words, a lower dose of a standard iron supplement may also reduce symptoms for some people.
Dietary Strategies to Support Iron Status
Diet plays a role in both preventing iron deficiency and supporting treatment. It helps to first identify how many iron-rich foods currently feature in the diet and then increase these where possible.
Iron in food comes in two forms. Heme iron comes from animal sources and is more efficiently absorbed. Helpful sources include lean red meat, liver and other offal, dark poultry, sardines, and other oily fish.
Non-heme iron comes from plant-based sources and is less efficiently absorbed. Even so, these foods can still contribute meaningful iron intake. Options include lentils, chickpeas, kidney beans, baked beans, tofu, tempeh, nuts and seeds, iron-fortified cereals, and dark leafy greens. Fortified foods can be particularly useful when daily iron needs are higher.
How to Improve Iron Absorption With Food
Vitamin C can improve iron absorption. It helps convert iron into a form that is more easily absorbed and keeps it soluble as it moves through the intestines. Pairing iron-rich foods with vitamin C-rich options can therefore support iron intake, especially for plant-based iron sources.
Inhibitors can also reduce absorption. Tea and coffee contain compounds that can interfere with iron absorption. These factors often act as small contributors rather than the main cause, so it helps to focus first on overall intake and consistency, then use strategies like spacing tea or coffee away from iron-rich meals or supplements where practical.
Daily Iron Requirements
Iron needs vary by age, sex, and life stage. For most adult women, the daily target is 18 milligrams. After age 51, this target drops to eight milligrams per day. Adult men generally require eight milligrams per day. Pregnancy increases requirements significantly, with a target of 27 milligrams per day.
People who follow a vegetarian or vegan diet may need to increase iron intake to achieve a similar amount of absorbable iron, because non-heme iron absorbs less efficiently.
To put the numbers into context, around 100 grams of red meat provides roughly 2.5 milligrams of iron, while 200 grams provides around five milligrams. This makes it easier to see why higher-requirement groups may struggle to meet targets through diet alone, particularly when trying to correct a deficiency rather than maintain normal levels.
Summary
Iron deficiency can drive fatigue and reduce performance, yet it often improves with the right approach. Testing provides clarity, supplements can correct deficiency efficiently, and dietary strategies help support both treatment and longer-term maintenance. Consistency matters, and small adjustments to dosing and food pairing can make iron supplementation easier to tolerate and sustain.