Feeling tired, weak, and constantly battling brain fog? If you're among the many grappling with low ferritin levels, you're not alone. Iron deficiency affects approximately 30% of the world's population, making it one of the most prevalent nutritional deficiencies globally. The good news is that natural strategies, including making mindful dietary choices and supplementing with therapeutic doses of iron, can correct this problem.

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Understanding Iron and Ferritin in the Body

Iron is a mineral that primarily functions as a component of hemoglobin, the protein in red blood cells responsible for transporting oxygen throughout the body. Iron is also an indispensable component of myoglobin, the protein in muscles that facilitates oxygen storage.

Beyond oxygen distribution, iron is involved in enzymatic reactions for energy metabolism, DNA synthesis, cell growth, immune function, and cognitive development and function. (31) 

Ferritin is a protein that is the body's primary storage form of iron. It's found in virtually all cells and is particularly concentrated in the liver, spleen, and bone marrow. Ferritin molecules can store thousands of iron atoms within their structure, releasing them as needed to maintain physiological functions.

While iron is essential for normal physiology, excess iron is toxic to cells because it can generate reactive oxygen species (ROS). ROS can damage cellular DNA and proteins, triggering inflammation. Therefore, ferritin is a buffer that stores excess iron to protect the body. Conversely, ferritin releases iron into circulation when iron levels are low. (27)

Signs and Symptoms of Low Ferritin

Low ferritin levels indicate iron deficiency, which can lead to a range of signs and symptoms affecting various bodily functions. Some common signs and symptoms of low ferritin include:

• Fatigue
• Muscle weakness, especially during physical activity
• Pale skin
• Shortness of breath, particularly during exertion or exercise
• Fast heart rate
• Headaches
• Dizziness or lightheadedness
• Cold hands and feet
• Brittle nails
• Hair loss
• Difficulty concentrating and impaired memory
• Cravings for non-food items, such as dirt, ice, or paper
• Restless legs syndrome (RLS)
• Microcytic anemia

Causes of Low Ferritin

A low ferritin level indicates iron deficiency. The most common causes of low ferritin levels include insufficient dietary intake, blood loss, and malabsorption. (6, 7)

A diet low in iron-rich foods, such as vegetarian and vegan diets, can lead to insufficient iron intake (4). 

Periods of rapid growth, such as infancy, adolescence, or pregnancy, can increase iron requirements. Additionally, athletes or individuals with high physical activity levels may require more iron to support increased red blood cell production and oxygen delivery to muscles. (6, 26) 

Chronic blood loss from gastrointestinal bleeding (ulcers, hemorrhoids, inflammatory bowel disease), heavy menstrual periods, or frequent blood donation can deplete iron stores over time. (4, 7)

Conditions affecting the gastrointestinal tract, such as celiac disease, Crohn's disease, or gastric bypass surgery, can impair iron absorption from food. (6) 

How to Test and Interpret Ferritin Levels

The ferritin test involves drawing a blood sample from a vein, typically from the arm. The blood is collected in a vial and sent to a laboratory for analysis. In most cases, no special preparation is required for a ferritin test. However, healthcare providers may advise fasting and avoiding iron supplements before the blood draw. (20) 

Measure ferritin through Rupa Health with one of these tests:

• Ferritin (FER) by ZRT Laboratory
• Ferritin by BostonHeart Diagnostics
• Ferritin by Access Med Labs

The lab will report ferritin results in nanograms per milliliter (ng/mL). Different labs may have different reference ranges for ferritin levels, but in general, you can use these normal ranges to interpret ferritin lab results:

Ferritin values below the lower end of the reference range are considered low, whereas values above the upper end of the reference range will be flagged as high. You'll notice these ranges are big. This puts some people with iron deficiency at risk of being undiagnosed. (11) 

To address this potential problem, many standard guidelines recommend treating iron deficiency when ferritin levels are below 30 ng/mL, even if the laboratory does not mark ferritin as low. Other medical guidelines, like the Ontario Association of Medical Laboratories (OAML), provide optimal ranges for interpreting ferritin levels. Many naturopathic doctors have a target ferritin level between 60-90 ng/mL for their patients.

OAML Ferritin Reference Ranges

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Dietary Approaches to Boost Ferritin

Dietary iron comes in two forms: heme and non-heme. Understanding the two forms of dietary iron is important for implementing nutritional strategies that optimize iron absorption and effectively boost iron levels in the body.

Heme Iron

95% of functional iron in the body is in heme form. Heme iron is derived from hemoglobin and myoglobin in animal-based foods (red meat, poultry, and fish) and is absorbed two to three times better than non-heme iron (4, 24).

Non-Heme Iron

Non-heme iron is found in plant-based foods, as well as in animal-based foods in smaller amounts. Plant-based sources of non-heme iron include: 

• Legumes (beans, lentils)
• Nuts
• Seeds
• Whole grains
• Leafy green vegetables

Non-heme iron absorption is lower than heme iron, with absorption rates as low as 2% (24). 

Nutritional Strategies to Enhance Iron Absorption

Consume Vitamin C-Rich Foods: Vitamin C enhances non-heme iron absorption by converting ferric iron to an absorbable ferrous iron (24). Vitamin C-rich foods include: 

• Citrus fruits
• Strawberries
• Kiwi
• Bell peppers
• Broccoli
• Tomatoes

Pair Iron-Rich Foods with Meat, Fish, or Poultry: Consuming heme iron-rich foods alongside non-heme iron sources can enhance iron absorption. For example, adding chicken to a spinach salad or having beans with a small portion of beef can improve non-heme iron uptake. (24) 

Limit Consumption of Iron Absorption Inhibitors with Iron-Rich Meals: Certain compounds, such as phytates, polyphenols, and calcium, can inhibit iron absorption. While these nutrients confer health benefits, consider moderating their intake during meals containing iron-rich foods. (4, 24) 

• Phytates: legumes, whole grains, nuts, seeds, tofu
• Polyphenols: coffee, black tea, herbal tea, and some fruits and vegetables
• Calcium: milk, yogurt, cheese, kale, broccoli, bok choi (2) 

Cook in Cast Iron Cookware: Cooking acidic foods (like tomato sauce) in cast iron cookware can increase iron content in the meal. Studies suggest that this method of cooking may help treat iron deficiency anemia.

Soak Beans and Legumes in Water Before Cooking: Soaking beans in water before cooking them can degrade the phytates and polyphenols that block non-heme iron absorption (16, 32).

Supplements to Increase Ferritin Levels

The most frequently used forms of iron in dietary supplements include ferrous and ferric iron salts. Ferrous iron is more bioavailable than ferric iron. (25) 

When looking at the nutritional label of iron supplements, you may see various forms of iron salts, including ferrous sulfate, ferrous gluconate, or ferrous fumarate, each containing differing amounts of elemental iron. For example, ferrous sulfate is 20% elemental iron by weight, whereas ferrous gluconate is 12% elemental iron. This is important because medical guidelines for treating iron deficiency reference milligram doses of elemental iron. (25) 

Taking iron supplements on an empty stomach is best because food can decrease absorption by 40%. However, if patients consequentially experience gastrointestinal upset, taking iron supplements with a meal can mitigate this side effect. (43)

Retesting Ferritin Levels

Medical guidelines recommend treating iron deficiency anemia in adults with 120 mg of elemental iron daily for three months or in children with 3 mg/kg (up to 60 mg) per day. Labs should be reassessed after one month to confirm an adequate response to therapy. (33)

If levels have not increased sufficiently after one month, intravenous (IV) iron can be considered. Iron sucrose is commonly infused in the United States because of its low associated incidence of anaphylaxis. Mild side effects, including headache, nausea, and diarrhea, may occur after an IV infusion. (33)

Lifestyle Considerations and Additional Tips

Because intestinal health is critical to optimal iron absorption, holistic treatment plans for boosting ferritin levels often include gut-healing strategies. To do this, you can: 

• Remove offending foods from the diet that may contribute to intestinal inflammation or leaky gut.
• Manage stress with stress-reduction techniques, including meditation, yoga, and adaptogenic herbs (35, 40).
• Focus on getting a good night's sleep. Poor sleep negatively affects digestion by impacting gut motility, digestive secretions, and the gut microbiome. 
• Use gut-healing supplements, such as L-glutamine, zinc carnosine, and probiotics.

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Key Takeaways

• Maintaining healthy iron levels is essential for optimal health. Ferritin is the biomarker that represents total-body iron status.
• Making informed nutritional choices can reduce the risk of developing iron deficiency. When necessary, iron supplementation can effectively treat low ferritin levels.
• There are many reasons why ferritin levels may be low. Working closely with a healthcare provider, you can determine and correct iron deficiency's underlying cause(s) to achieve long-term resolution.