What is Spirulina?

Spirulina or Arthrospira is a blue-green alga that became famous after it was successfully used by NASA as a dietary supplement for astronauts on space missions [i]. Spirulina grows in both fresh and saltwater sources and is known for its high protein and micronutrient content

What are the benefits of spirulina?

It has a long history of use as a therapeutic food and it has been reported that it was used during the Aztec civilisation to boost endurance [ii].

Nutritional benefits of spirulina

Thiamine (vitamin B1)

Riboflavin (vitamin B2)

Niacin (vitamin B3)

Copper

Iron

It is often claimed that spirulina contains vitamin B12. However, the form of B12 it does contain is not in the correct format for use in humans.

Based on the essential amino acids content, the use of Spirulina as a supplement food can provide the daily needs of essential amino acids [iii].

Weight balance and cholesterol

Overall, spirulina has several benefits for improving weight loss and unfavourable cholesterol panels [iv] [v]. However, further research including larger clinical trials would be warranted for confirming these benefits.

Another study in people with high cholesterol determined that 1 gram of spirulina per day lowered triglycerides by 16.3% and “bad” LDL by 10.1% [vi]. Several other studies have found favourable effects, with higher doses of 4.5–8 grams per day [vii] [viii].

Allergy reduction and rhinitis

In one study in 127 people with allergic rhinitis, 2 grams per day dramatically reduced symptoms like nasal discharge, sneezing, nasal congestion and itching [ix].

Diabetes and blood sugar control

In a two-month study in 25 people with type 2 diabetes, 2 grams of spirulina per day led to a significant reduction in blood sugar levels [x].

Studies were conducted on phycocyanin, a pigment-protein found in spirulina, to ascertain potential benefits in diabetes treatment. In mice it was seen to enhance insulin sensitivity and reduce fasting blood sugar [xi] [xii].

Protective properties

Chronic inflammation contributes to cancer and other diseases. Many antioxidants in spirulina have anti-inflammatory effects in the body.

Studies have shown it reduces liver toxicity in rats and has shown promise for preventing tumour growth [xiii] [xiv].

In human studies, spirulina has shown protective effects against cancer of the mouth [xv] [xvi] [xvii].

Anaemia

Anaemia may occur for many different reasons. However, one of the most common forms of anaemia is characterised by a reduction in haemoglobin, which make up the red blood cells.

In a study in 40 older adults with a history of anemia, spirulina supplements increased the haemoglobin content of red blood cells and thus improved immune function [xviii].

Energy, muscle strength and endurance

Carbohydrates contained in Spirulina help in energy release. Spirulina increases healthy lactobacillus bacteria in the intestinal microbiome, enabling the production of Vitamin B6 that also helps in energy release.

Spirulina supplementation induced a significant increase in exercise performance. The antioxidant function of spirulina reduced oxidation typically driven by exercise, and also improved the action of the body’s own antioxidant; glutathione [xix].

Results from another study suggest that spirulina showed a preventive effect against the skeletal muscle damage that probably led to postponement of the time of exhaustion during intense exercise [xx].

Spirulina also contains magnesium. This mineral supports normal daily functions like muscle function and maintaining steady heartbeat. This mineral also responsible for producing protein and creating energy.

Blood pressure reduction

High blood pressure is a driver of many serious illnesses, including heart attacks, strokes and chronic kidney disease. Whilst 1 gram of spirulina was seen to be ineffective, a dose of 4.5 grams per day has been shown to reduce blood pressure in individuals [xxi] [xxii].

This action is thought to be attributed to an increased production of nitric oxide, a signalling molecule that helps your blood vessels relax and dilate.

Potential risks of spirulina

It is advisable to ensure use of a reputable brand from a good source as some spirulina harvested in the wild may be contaminated with heavy metals and bacteria. In high amounts, some of these toxins may stress or damage your liver.

Use in pregnancy

There is, as yet, insufficient evidence to suggest blue-green algae is safe for pregnant or breastfeeding women. Because of the toxin risk, it is recommended that pregnant women avoid spirulina.

Bleeding disorders

Because spirulina can help reduce blood clotting, it may increase the risk of bruising and bleeding in people with certain bleeding conditions.

Diabetes

Spirulina might affect blood sugar levels, so people with diabetes should monitor their blood sugar when taking spirulina.

Autoimmune diseases

Research shows that spirulina can support immune system function. However immune system activation may worsen symptoms in those with auto-immune diseases including lupus, multiple sclerosis, or arthritis. Talk to your GP before adding spirulina to your diet if you have an auto-immune condition.

Medication interactions

Spirulina’s health benefits may interact with or counter certain medications. Medications which may cause interactions include those used to treat diabetes, immunosuppressants, and blood thinners.