Iron Supplements Aren’t Always the Solution for Low Iron

Iron deficiency is common, especially in active females. You may have personally experienced the impacts in not just your training, but every day life of iron deficiency or anemia (which aren't the same and I will explain more below!) and know the feeling of dragging through.

But is taking a supplement always the right solution? What about long term? What if you are taking a supplement but still have low levels... Let’s dig into why iron supplements may not always work, how iron functions in the body, and what to consider before supplementing.

Iron Deficiency and Anemia

Anemia is a general term for having fewer red blood cells or a reduced amount of hemoglobin in each red blood cell. This results in insufficient oxygen being delivered to tissues. While iron deficiency anemia (IDA) is the most prevalent form, other types of anemia, like megaloblastic anemia (often caused by B12 or folate deficiency), can also contribute to low iron levels.

Anemia is a symptom, not a diagnosis, and should prompt further investigation into underlying causes. It’s not just about low iron—other factors, such as inflammation, stress, or nutrient deficiencies, may play a role.

Understanding Iron, Iron Metabolism and Absorption

Iron is one key mineral for energy production and oxygen transport. If you have ever dealt with iron deficiencies, you know the feeling of trying to live life, let alone train depleted.

Other symptoms may include

Heavy menstrual bleeding (also a cause)
Extreme fatigue or lack of energy
Unexplained Weakness
Pale skin
Chest pain, fast heartbeat, or shortness of breath, especially when active
Headache, dizziness, or lightheadedness
Cold hands and feet
Brittle nails or hair loss
Unusual cravings

The body has an intricate system for regulating iron absorption, transport, and storage. For example:

Hepcidin is the "master regulator" of iron homeostasis. When iron levels are low, hepcidin decreases to allow more iron absorption. Conversely, when iron is abundant, hepcidin increases to limit absorption and prevent overload.
Iron Absorption occurs primarily in the duodenum. However, conditions like low stomach acid, inflammation, or gut infections (such as H. pylori) can impair this process.

When testing for iron deficiency, ferritin (which stores iron) and transferrin saturation can provide early insights into iron deficiency before it becomes anemia.

Common Causes of Iron Deficiency

Blood Loss: Heavy menstrual bleeding, gastrointestinal bleeding (due to conditions like Crohn’s disease or ulcers) can deplete iron stores.
Dietary Deficiency: A diet lacking in iron-rich foods, especially heme iron from animal sources (e.g., red meat, organ meats), can result in iron deficiency. While non-heme iron from plant sources (like beans and spinach) is beneficial, it’s less efficiently absorbed. I suggest cronometer.com to check for any holes in your habitual diet.
Poor Absorption: Conditions like low stomach acid, Celiac disease, or chronic inflammation (e.g., IBD) can impair nutrient absorption.
Increased Demand: During periods of growth, like pregnancy, or intense exercise, the body’s iron requirements increase!
Nutrient Synergy: Iron metabolism relies on other nutrients like vitamin A, B vitamins, and copper. Deficiencies in these can impair iron absorption and recycling.

Why Iron Supplements Aren’t Always the Solution

Popping iron pills seems like the obvious solution when iron levels are low, but it often misses the real issue. Here’s why:

Absorption Issues: Iron supplementation won’t do much if the body isn’t able to absorb the iron properly. Low stomach acid, gut inflammation, or infections like H. pylori can block iron from being absorbed from the gut, no matter how much you take. Gut issues are common culprits, but they’re often overlooked, and fixing the gut comes before just adding more iron.
Athletes Need More Than Iron - Intense training raises hepcidin, a hormone that blocks iron absorption In general, athletes need more of a lot of other micronutrients too. Assessing diet first – including carbohydrate intake ( many women aren’t eating enough carbs!) might be a better first step before any supplements. Low carbs can mess with your iron absorption too, especially in athletes.
Nutrient Synergy: Iron doesn't work alone. It depends on copper, vitamin A, and B vitamins to be properly absorbed and recycled. Without those, iron might just sit there, unused, or worse, end up accumulating in tissues, which isn’t helpful.
Inflammation & Stress: Chronic inflammation raises hepcidin, which again, blocks iron absorption. But inflammation doesn’t just come from an injury—it can be chronic, stemming from things like poor sleep, stress, or an underlying infection.
Impaired Liver Function: The liver plays a huge role in iron metabolism. If there’s an issue with liver function (think inflammation, poor digestion, or gut infections), iron won’t be properly transported or recycled. So, if you're dealing with liver stress, taking iron supplements may make things worse because of that impaired recycling system.
Heavy Menstrual Bleeding: Yes, excessive bleeding leads to iron loss, but it's also a sign that something’s off. If your client is experiencing heavy periods, iron supplements might be the immediate fix, but the root cause of the bleeding needs to be addressed too.
Iron Overload Risk: Iron supplementation, without monitoring ferritin levels, can lead to oxidative stress and gut irritation. In some cases, iron overload can even cause iron to accumulate in tissues, making things worse. This is why it's essential to not only supplement but also monitor iron storage carefully with follow up labwork.

What to Do Before Supplementing

Before jumping to the pill bottle, here’s what you should focus on instead:

Test First: Never assume that low iron is the only issue. A comprehensive iron panel—serum iron, ferritin, transferrin saturation—will give you a better picture. When it comes to testing, it’s not just about whether a lab result falls within the ‘normal’ range. Optimal will come down to the individual. . We generally want to see a functional range of 70-130 µg/dL for serum iron and a ferritin between 50 and a ferritin between 50-100 ng/ml. Check out the full set of labs like your CBC, CMP, and thyroid panels to get the most accurate read on what’s going on as symptoms overlap.
Support Gut Health: Iron won’t get where it needs to go if your gut can’t absorb it. Poor gut health, including leaky gut or gut infections (like H. pylori or Candida), mess with absorption. Fixing the gut is key—no amount of supplementation will replace a healthy digestive system. Focus on healing the gut lining and reducing inflammation from the inside out. A good, solid digestive system is your first line of defense.
Optimize Nutrient Synergy: Iron depends on copper, vitamin A, and B vitamins—without these, iron won’t get to work. Help clients improve their diet with foods rich in these nutrients. For example, pairing plant-based iron with vitamin C (like spinach and orange) can enhance absorption. Make sure they’re getting enough copper and vitamin A to avoid disrupting the entire system. Vitamins and minerals are a team effort!
Lower Inflammation: If inflammation is causing low iron absorption, it’s important to dig deeper into the sources—under eating (calories and micronutrients ) chronic stress, gut health, or even sleep quality. Once you address the root causes of inflammation, the iron can do its job more effectively. It’s not just about addressing low iron; it’s about fixing the environment in the body that’s preventing iron from doing what it needs to.
Whole Foods Over Supplements: Encourage clients to focus on whole food sources of iron first. Red meat, poultry, organ meats, eggs, oysters, and leafy greens are your go-to. Y want to focus on heme iron (from animal sources) because it’s more efficiently absorbed. Non-heme iron (from plant foods) is still important but requires a bit more effort to absorb.

Supplements

Iron supplements may be necessary, and certainly have their place!! For example, to help get out of a state of deficiency or anemia while under lying causes are addressed. Vegans and vegetarians as well as anyone with chronic medical conditions may need extra nutrient support.

Here’s what to keep in mind:

Supplement Forms: Iron supplements, especially ferrous sulfate, can irritate the digestive system, leading to nausea and constipation. For clients with GI issues (e.g., leaky gut, IBS), chat with providers about a ferrous bisglycinate or iron chelate, which are gentler on the stomach and better absorbed.
Monitoring & Dosage: Always monitor biofeedback and labs- especially ferritin levels to avoid iron overload and track progress. Ideally supplements wouldn’t be a long term solution. Taking iron with vitamin C can enhance absorption- which may or may not be beneficial. Take away from coffee/caffeine as it can inhibit uptake.

Iron deficiency and anemia are complex, and supplements are not always the solution. By testing, assessing nutrient synergy, and addressing gut health and inflammation, you can create a more effective plan for resolving low iron.

Always look beyond the symptom (low iron) to find and treat the root cause. If you are struggling with poor gut health, heavy menstrual bleeding or suspect your liver needs some love- check out our guides for assistance and to learn more to support your body.