I still remember sitting on the couch at night, chewing ice.
Not a few cubes here and there. Entire bowls of ice.
At the time, I was in my late 20s. I was eating a plant-based diet, exercising regularly, getting into running, and doing everything I thought I was supposed to do for my health. Yet I was exhausted all the time. I couldn’t stay awake past 9 p.m. My legs felt achy at night. My workouts felt harder than they should.
I chalked it up to a busy schedule.
What I didn’t realize was that these were signs of severe iron deficiency anemia.
Years later, as a sports dietitian working with runners, I’ve seen the same pattern repeat itself over and over again, especially among female athletes and plant-based runners. Many assume their fatigue is simply part of training. Others think they’re out of shape.
In reality, low iron was the culprit.
Why I’m More Prone to Iron Deficiency
My situation is a little unique because I have thalassemia trait, an inherited blood disorder that affects hemoglobin production.
Hemoglobin is the protein in red blood cells responsible for carrying oxygen throughout the body. Because my body naturally produces less hemoglobin than average, I’ve spent most of my life monitoring my iron status.
As a child, I managed my iron levels through diet. But once I became a runner, things changed.
Running increases your body’s demand for oxygen delivery, and it increases the rate at which you lose iron. Iron losses occur through sweat, urine and even red blood cell breakdown when your feet hit the pavement. That means iron becomes even more important for runners.
While thalassemia trait increases my personal risk, I’ve learned that iron deficiency is incredibly common among most runners, even those without underlying conditions.
Signs of Iron Deficiency in Runners
Iron deficiency symptoms can be subtle at first. They also mimic symptoms many people feel on a daily basis, like headache or fatigue.
Some of the most common signs include:
- Persistent fatigue
- Declining running performance
- Difficulty recovering from workouts
- Feeling cold frequently
- Shortness of breath during exercise
- Hair loss
- Restless legs
- Headaches
- Pale skin
One symptom that surprised me was PICA, which is a craving for non-food items. For me, that showed up as an intense desire to chew ice every night. Some people who experienec PICA eat dirt, clay or other non-food items.
At the time, I had no idea that craving ice can be associated with iron deficiency. Looking back, it was one of the biggest red flags.
Why Runners Are at Higher Risk for Low Iron
Iron plays a critical role in transporting oxygen throughout the body. Without enough iron, your muscles don’t receive the oxygen they need to perform efficiently.
For runners, several factors can increase iron losses:
1. Menstruation
Female athletes lose iron every month through menstrual blood loss.
2. Sweat Losses
Small amounts of iron are lost through sweat, which can add up during heavy training.
3. Foot Strike Hemolysis
Every time your foot hits the ground while running, some red blood cells break down.
This process, known as foot strike hemolysis, is another contributor to iron losses in endurance athletes.
4. Increased Training Demands
Higher training volume increases the body’s need for oxygen transport, placing greater demands on iron stores.
Are Plant-Based Runners More Likely to Be Iron Deficient?
The answer is yes, but not because plant-based diets are inherently deficient in iron.
Plant foods contain iron. In fact, many plant foods are excellent sources. The challenge is that plant foods contain non-heme iron, which isn’t absorbed as efficiently as the heme iron found in animal foods.
That means plant-based athletes need to be more intentional about their iron intake. Research suggests vegetarians and vegans may need up to 1.8 times more dietary iron than omnivores because of these absorption differences.
This doesn’t mean a plant-based diet causes iron deficiency. It simply means you need a strategy.
Best Plant-Based Iron Sources for Runners
Some of my favorite iron-rich plant foods include:
- Lentils
- Beans
- Tofu
- Tempeh
- Edamame
- Pumpkin seeds
- Hemp seeds
- Quinoa
- Iron-fortified cereals
- Soy foods
These foods can absolutely support healthy iron levels when included consistently.
The Iron Absorption Trick Every Runner Should Know
If there’s one nutrition strategy I wish more athletes knew, it’s this:
Pair iron-rich foods with vitamin C. Vitamin C significantly improves iron absorption. Below are some ways to do this efficiently.
Iron + Vitamin C Combinations
- Oatmeal + strawberries
- Lentils + tomatoes
- Tofu stir fry + bell peppers
- Black beans + salsa
- Pumpkin seeds + orange slices
When I was prescribed iron supplements, my doctor specifically instructed me to take them with vitamin C to improve absorption. The same principle applies to food.
Foods That Can Interfere With Iron Absorption
There are also foods and beverages that may reduce iron absorption.
Calcium
Large amounts of calcium consumed alongside iron-rich meals can interfere with absorption.
Examples include:
- Milk
- Yogurt
- Cheese
- Calcium supplements
Coffee and Tea
Coffee and tea contain compounds that can inhibit iron absorption.
If you’re taking an iron supplement, avoid taking it with your morning coffee.
Personally, I take iron before bed when I’m not consuming caffeine.
When Diet Isn’t Enough
One of the biggest misconceptions I hear is that severe iron deficiency can always be fixed through food alone. Unfortunately, that’s often not the case.
When my ferritin level dropped to just 2 ng/mL, dietary changes weren’t enough. I needed iron supplementation under medical supervision.
If you suspect low iron, don’t self-diagnose. Ask your healthcare provider about blood work, including ferritin levels, which measure your iron stores.
Iron supplementation can be incredibly effective when necessary, but taking iron without medical guidance isn’t recommended because excess iron can also be harmful.
What I Wish I Knew Sooner
Looking back, I wish I had paid attention to the warning signs sooner. I wish I had recognized that constant exhaustion wasn’t normal. I wish I had known that feeling slower on my runs didn’t automatically mean I was out of shape.
Most importantly, I wish I had understood that iron deficiency wasn’t a sign that my plant-based diet was failing. It was simply a nutrition issue that required attention and management.
Today, I still run. I still eat a plant-based diet. And I still monitor my iron levels closely. For me, iron management isn’t about perfection.
It’s about awareness. Because when your iron levels are where they should be, you feel the difference—not just in your running, but in every part of your life.
The Bottom Line
Iron deficiency is one of the most common nutrition issues I see among runners, particularly female athletes and plant-based athletes. The good news is that it’s manageable.
Know the symptoms. Prioritize iron-rich foods. Pair iron with vitamin C. Get routine blood work if you’re at risk. And if something feels off, don’t ignore it. Your body is usually trying to tell you something.
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