Is Spirulina High in Iron?

Written by: Pard Bharaj



Time to read 10 min

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Author: Pard Bharaj

I am a dedicated researcher with nearly a decade of experience in investigating health best practices. 

Disclaimer: The information provided in this article is for educational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition or before making any changes to your diet or lifestyle, especially if you have existing health conditions.


Spirulina is a type of blue-green algae that has gained popularity as a dietary supplement due to its rich nutritional content. Often referred to as a superfood, Spirulina is packed with proteins, vitamins, minerals, and antioxidants, making it a valuable addition to a balanced diet. One of the critical nutrients found in Spirulina is iron, an essential mineral for various bodily functions. 

This article aims to explore whether Spirulina is high in iron and how it compares to other iron-rich foods, helping you make informed dietary choices..

Importance of Iron in the Diet:

Iron is a vital mineral that plays a crucial role in maintaining good health and overall well-being. It is an essential component of haemoglobin, the protein in red blood cells responsible for carrying oxygen from the lungs to the rest of the body. Adequate iron intake is necessary for various physiological functions and helps prevent iron deficiency (anaemia), a common condition affecting millions worldwide.

Key roles of iron in the diet include:

  • Oxygen Transport:¬†Iron is essential for the formation of haemoglobin, which transports oxygen in the blood.

  • Energy Production:¬†Iron is involved in the conversion of nutrients into energy within cells.

  • Immune Function:¬†Adequate iron levels support a healthy immune system, aiding in the fight against infections.

  • Cognitive Function:¬†Iron is crucial for proper brain function and cognitive development, particularly in children.

  • Muscle Function:¬†Iron is a component of myoglobin, a protein that supplies oxygen to muscles, aiding in muscle metabolism and endurance.

Is Spirulina High in Iron?

Yes, Spirulina is considered high in iron. Spirulina contains approximately 28.5 mg of iron per 100 grams! This makes it significantly higher than many traditional iron-rich foods. 

This high iron content makes Spirulina a particularly potent source of iron, especially for vegetarians, vegans, and those with dietary restrictions that limit the intake of animal-based iron sources. Including Spirulina in your diet can help meet daily iron requirements more efficiently, contributing to better overall health and well-being.

Comparison with Other Common Iron-Rich Foods: 

To understand Spirulina's iron content in context, it's helpful to compare it with other well-known iron-rich foods:

  • Spirulina:¬†Approximately 28.5 mg of iron per 100 grams

  • Spinach:¬†¬†Approximately 2.7 mg of iron per 100 grams.

  • Red Meat (beef):¬†Around 2.6 mg of iron per 100 grams.

  • Lentils:¬†¬†About 3.3 mg of iron per 100 grams.

  • Quinoa:¬†Roughly 1.5 mg of iron per 100 grams.

Is Spirulina High in Iron?  Food Comparison Table

Bioavailability of Iron in Spirulina:

Explanation of Bioavailability:

Bioavailability refers to the extent to which a nutrient is absorbed and utilised by the body. When it comes to iron, bioavailability can be affected by its form (heme or non-heme), dietary components, and individual health factors. Heme iron, found in animal products, is generally more easily absorbed than non-heme iron, which is present in plant-based foods like Spirulina.

How Well the Body Absorbs Iron from Spirulina:

Spirulina contains non-heme iron, which typically has a lower absorption rate compared to heme iron. However, the bioavailability of iron from Spirulina is relatively high for a plant-based source due to its unique nutritional composition. The presence of vitamin C and other antioxidants in Spirulina can enhance the absorption of non-heme iron, making it more effective than other plant-based iron sources.

Although the absorption rate of iron from Spirulina may not match that of heme iron sources like red meat, it remains a valuable and potent source of iron. Consuming vitamin C-rich foods, such as citrus fruits or bell peppers, alongside Spirulina can further improve iron absorption, ensuring better utilisation by the body.

Dr Eric Berg said this about the Iron in Spirulina "It has really good absorbable iron and folate, it has 6 times more absorption than normal iron supplements". Dr. Arsalan Aspires said this about Spirulina "In one tablespoon, you get a whopping 4 grams of protein, 1.6 grams of carbs, half a gram of fat, 2 mg of iron, as well as 21% of your needed copper for the day."

Potential Side Effects and Considerations: 

While Spirulina is generally regarded as safe and beneficial, the following information is worth reading before taking this supplement.

  • Allergic Reactions:¬†Some individuals may experience allergic reactions, including rashes, swelling, or difficulty breathing. Discontinue use if any allergic symptoms occur.

  • Digestive Issues:¬†May cause gastrointestinal discomfort such as bloating, gas, or diarrhoea in some individuals.

  • Medication Interactions:¬†Spirulina can interact with immunosuppressants and other medications. Consult your healthcare provider before starting.

  • Contaminants:¬†Ensure Spirulina is sourced from reputable suppliers to avoid contamination with heavy metals or harmful bacteria. Always, go for an organic source as these tend to have more antioxidants and free from chemicals.

  • Autoimmune Concerns:¬†Spirulina can stimulate the immune system, which might be problematic for individuals with autoimmune diseases.

  • Pregnant Women:¬†Pregnant women should exercise caution and consult their healthcare provider before taking Spirulina to ensure it is safe for their specific situation.

Recommended Daily Intake: 

Iron requirements vary depending on age, sex, and life stage. Ensuring an adequate intake of iron is crucial for maintaining health and preventing iron deficiency anaemia. Different demographics have specific daily iron intake recommendations to meet their unique physiological needs.

Men typically require around 8 mg of iron per day, while women, generally need about 18 mg per day. These values ensure that the body receives enough iron to support essential functions and maintain overall health. However as a general guideline, don't use more than what's listed on your product's label. Manufacturer recommendations might vary and there's no recommended "effective" dosage of spirulina so it is best to start very low and see how the body adjusts.

Please consult your healthcare provider before taking Spirulina to ensure it is safe for their specific situation.

References and Further Reading:

1. Iron Speciation and Iron Binding Proteins in Arthrospira platensis Grown in Media Containing Different Iron Concentrations

Summary: This study investigates the effects of varying iron concentrations in the culture media on the biochemical composition, iron bioaccumulation, and iron speciation in Arthrospira platensis (Spirulina). It was found that iron content in Spirulina biomass ranged from 0.35 to 2.34 mg/g dry weight, depending on the iron concentration in the culture medium. The study also examined the role of C-phycocyanin as an iron-binding protein. These findings provide insights into iron metabolism in cyanobacteria and support the potential of Spirulina as a source for iron-enriched supplements.

Authors: Isani, G.; Niccolai, A.; Andreani, G.; Dalmonte, T.; Bellei, E.; Bertocchi, M.; Tredici, M.R.; Rodolfi, L.

2. Spirulina supplementation: A double-blind, randomized, comparative study in young anemic Indian women

Summary: This study evaluates the impact of spirulina supplementation on haemoglobin and serum ferritin levels in young women with iron-deficiency anaemia. The participants, aged 18-21, consumed either a placebo snack bar or a snack bar supplemented with 3 grams of spirulina daily. Over a period of 90 days, no significant changes were observed in haemoglobin and serum ferritin levels between the two groups. Despite being well tolerated, the study suggests that spirulina supplementation in the given form and dosage did not effectively improve iron status in the participants. 

Authors: Lucia C. Leal-Esteban, Renata Campos Nogueira, Mariana Veauvy, Benedict Mascarenhas, Mandar Mhatre, Sasikumar Menon, Bertrand Graz, Denis von der Weid.

3. Iron (Fe) biofortification of Arthrospira platensis: Effects on growth, biochemical composition and in vitro iron bioaccessibility

Summary: This study examines the effects of iron biofortification on the growth, biochemical composition, and iron bioaccessibility of Arthrospira platensis (Spirulina). The research found that increasing iron concentrations in the growth medium did not affect the growth of Spirulina but significantly enhanced its iron content, achieving an almost 150-fold increase. The biochemical composition of Spirulina was altered, with a decrease in protein, lipid, and phycocyanin content. However, the bioaccessible iron per gram of biomass significantly increased, indicating its potential as a dietary iron source to combat iron deficiency anaemia (IDA).

Authors: Eleni Kougia, Efstathia Ioannou, Vassilios Roussis, Ioannis Tzovenis, Imene Chentir, Giorgos Markou

4. Iron Availability from Iron-Fortified Spirulina by an in Vitro Digestion/Caco-2 Cell Culture Model 

Summary: This study examines the iron availability from iron-fortified Spirulina using an in vitro digestion/Caco-2 cell culture model. The results show that iron-fortified Spirulina leads to a significantly higher ferritin formation compared to other iron sources such as beef, yeast, and wheat flour. Specifically, the Spirulina digest demonstrated a 6.5-fold increase in iron bioavailability per microgram of iron used, compared to beef digest. These findings suggest that Spirulina is a highly effective source of dietary iron and could be an adequate means to address iron deficiency anaemia.

Authors: Grégoire Puyfoulhoux, Jean-Max Rouanet, Pierre Besançon, Bruno Baroux, Jean-Claude Baccou, Bertrand Caporiccio

5. Arthrospira platensis (Spirulina) fortified functional foods ameliorate iron and protein malnutrition by improving growth and modulating oxidative stress and gut microbiota in rats

Summary: This study examines the impact of Spirulina-fortified foods (sattu and chikki) on protein and iron malnutrition in rats. Spirulina significantly enhanced the protein and iron content of these foods and improved the antioxidant capacity. Supplementation promoted bodyweight gain, restored haemoglobin, serum protein, iron levels, and reduced oxidative stress. It also positively modulated gut microbiota, increasing beneficial microbes while reducing harmful ones. The findings suggest Spirulina-fortified foods can effectively address protein and iron deficiency. 

Authors: Raman Kumar, Vinesh Sharma, Sampa Das, Vikram Patial, Vidyashankar Srivatsan

6. The effects of spirulina supplementation on serum iron and ferritin, anemia parameters, and fecal occult blood in adults with ulcerative colitis: A randomized, double-blinded, placebo-controlled trial

Summary: This randomized, double-blinded, placebo-controlled trial evaluated the impact of Spirulina supplementation (1 g/day for eight weeks) on anemia in adults with ulcerative colitis (UC). The Spirulina group showed significant increases in serum iron and mean corpuscular volume, while the placebo group experienced reductions in red blood cell count and hematocrit. No significant changes in fecal occult blood were observed. Spirulina supplementation improved anemia parameters in UC patients. 

Authors: Sajjad Moradi, Sahar Foshati, Fariborz Poorbaferani, Sepide Talebi, Reza Bagheri, Parsa Amirian, Fatemeh Parvizi, Michael Nordvall, Alexei Wong, Mehdi Zobeiri 

7. The effect of Spirulina supplementation on blood haemoglobin levels of anaemic adult girls

Summary: This study investigates the effect of Spirulina supplementation on blood haemoglobin levels in anaemic girls aged 18-22 years. Over 30 days, 20 participants consumed 5 g of Spirulina daily, either as syrup or in parathas. Results showed a mean haemoglobin increase of 1.17 g/dl (10.33%). The syrup group saw an 11.65% increase, while the paratha group had a 7.72% increase. The higher efficacy of the syrup was attributed to the absence of iron absorption inhibitors. Spirulina supplementation effectively improved haemoglobin levels, helping to combat iron deficiency anaemia.

Authors: U. Mani, Alefia Sadliwala, P. Parikh

8. Fourteen-Days Spirulina Supplementation Increases Hemoglobin, but Does Not Provide Ergogenic Benefit in Recreationally Active Cyclists: A Double-Blinded Randomized Crossover Trial

Summary:¬†This study examines the impact of 14-day Spirulina supplementation (6 g/day) on hemoglobin levels and cycling performance in recreationally active individuals. Seventeen participants completed a double-blinded, randomized crossover trial. Results showed a 3.4% increase in hemoglobin with Spirulina (150.4 ¬Ī 9.5 g/L vs. 145.6 ¬Ī 9.4 g/L, p = 0.047) but no significant improvements in cardiorespiratory performance metrics. Spirulina increased hemoglobin concentration but did not enhance cycling performance.¬†

Authors: Yunus Ali, Rama Aubeeluck, Tom Gurney 

10.The effects of Spirulina on anemia and immune function in senior citizens

Summary: This study examines the effects of Spirulina supplementation on anemia and immune function in senior citizens. Forty volunteers aged 50 years and older with a history of anemia were given Spirulina supplements for 12 weeks. The study measured complete blood count (CBC) variables and indoleamine 2,3-dioxygenase (IDO) enzyme activity at baseline, 6 weeks, and 12 weeks. Results indicated an increase in mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV), and mean corpuscular hemoglobin concentration (MCHC), particularly in male participants. Additionally, over 50% of participants showed increased IDO activity and white blood cell (WBC) counts, suggesting improved immune function. These findings support the potential of Spirulina to ameliorate anemia and immunosenescence in older adults, though further large-scale studies are recommended.

Authors: Carlo Selmi, Patrick SC Leung, Laura Fischer, Bruce German, Chen-Yen Yang, Thomas P Kenny, Gerry R Cysewski, M Eric Gershwin

11. Verywell Health Spirulina Review:

Spirulina is a nutrient-dense blue-green algae that offers various health benefits. It is rich in protein, vitamins, minerals, and antioxidants. Potential benefits include boosting the immune system, improving gut health, reducing inflammation, and supporting heart health. Spirulina may also help with managing allergies and improving endurance. However, it can interact with certain medications and may not be suitable for everyone, so it is advised to consult with a healthcare provider before adding it to your diet.

Frequently Asked Questions:

Is Spirulina a good source of iron?

Yes, Spirulina is considered high in iron, containing approximately 28.5 mg of iron per 100 grams. Beef in comparison has 2.6 mg of iron per 100 grams.

What is the bioavailability of iron in Spirulina?

While Spirulina contains non-heme iron, its absorption is relatively high for a plant-based source, especially when consumed with vitamin C-rich foods. Study number 4 in "references and further reading", showed the Iron in Spirulina to be more bioavailable then beef.

Can Spirulina help prevent iron deficiency anemia?

Yes, due to its high iron content, Spirulina can be an effective supplement to help prevent and manage iron deficiency anemia. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition or before making any changes to your diet.

Are there any side effects of taking Spirulina for iron?

Potential side effects include allergic reactions, digestive issues, and interactions with medications. It's important to source Spirulina from reputable suppliers to avoid contaminants.

Is Spirulina safe for pregnant women to increase their iron intake?

Pregnant women should consult their healthcare provider before taking Spirulina to ensure it is safe for their specific situation. Generally a good quality organic spirulina supplement can be beneficial.

Can Spirulina interact with other iron supplements or medications?

Yes, it's advisable to consult a healthcare provider to avoid potential interactions with other iron supplements or medications.

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