What's the deal with ... spirulina?

Spirulina is high in nutrients, but does it have any proven medicinal benefits?
Spirulina is high in nutrients, but does it have any proven medicinal benefits? Photo: iStock

Spirulina, now coined a superfood, has joined the list of surprising health ingredients riding the popularity wave in Australia, thanks to its supposed nutritional properties. While you may have heard of people adding spirulina to their smoothies here and there, it's beginning to become more mainstream, as people become increasingly aware of this nutrient powerhouse.

So what is it?

Spirulina is a blue-green algae, typically grown naturally in warm alkaline waters in subtropical climates. Spirulina is most well-known for its antioxidant and anti-inflammatory properties, and recent claims also suggest it has the ability to improve metabolic and heart health.

It also contains copper, thiamine, riboflavin, iron, omega-3 and omega-6 fatty acids, magnesium, potassium and manganese.

Accredited practicing dietitian Bronwen Greenfield said in addition to these nutrients, spirulina is also an excellent source of protein. "Approximately 65-70 per cent of spirulina is protein, and it contains all of the eight essential amino acids, making it a complete protein," she says.

How did algae get so big?

Aside from the obvious nutritional reasons, Greenfield adds that spirulina originally became popular after NASA used it successfully as a dietary supplement for astronauts travelling into space.

"Since then, it has gained increased attention due to its impressively dense nutrient concentration, and therefore it's potential as a nutraceutical [a food that has medicinal benefits]," she says.

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Too good to be true?

Current attention around spirulina claims the "superfood" may be beneficial to gut health, as well as capable of improving metabolism, protecting the heart, enhancing immunity and improving symptoms and effects of viruses, disease and even cancer.

However, Greenfield cautions against falling victim to these assertions, as there is limited scientific evidence to support them.

"Due to its anti-inflammatory components, hypothetically speaking, spirulina could be beneficial to gut health, yes, but there is not enough research in this area to confirm this," she says.

"There has been a small amount of research which suggests spirulina can inflict positive changes to the gut microbiota, however these [trials] were conducted in animals and not humans," she adds.

While it is being referred to as a "superfood" more regularly, Greenfield believes this classification can be problematic.

"The problem with 'superfoods' is that their reported benefits are often only seen when taking seriously high dosages of the particular food or supplement, which then means you are spending a ridiculous amount of money to achieve this," she says.

"Spirulina can be classified as a superfood because it is relatively dense in a variety of nutrients, however it is important to remember that superfoods such as spirulina should not be seen as the 'magic answer' to balancing out an unhealthy diet."

What's your best bet?

Greenfield says you're better off eating a variety of foods, including enough fruits and vegetables, wholegrains, nuts and seeds, proteins and healthy fats in your diet, as the best way to ensure you're meeting your nutrient requirements at minimal cost. 

She believes supplements like spirulina should be used to support a healthy diet, rather than replacing nutritious foods and filling in nutrient gaps.

Before rushing off to buy spirulina at your nearest health store, Greenfield urges people to consider the limited scientific evidence currently supporting claims around spirulina's health properties.

"It is important to remember that the claims surrounding spirulina and its efficacy are supported by rather weak scientific evidence and require further research, particularly in larger human samples, to further solidify these claims," she says. 

If you do choose to take spirulina as a supplement, she encourages purchasing it from a reputable manufacturer, to ensure the product has been tested for contaminants.

"Spirulina itself does not pose as a health risk to most individuals, however it may be contaminated with things that do, if you aren't careful. Sometimes it can absorb heavy metals from the water it grows in and as a result become contaminated with toxic substances," she says. Greenfield adds that being consistent with the recommended dosage and taking it daily will provide the most optimal benefits.

However, anyone who is pregnant or breastfeeding should avoid it, Greenfield says. "Some research also indicates that it could interact with anticoagulant, antiplatelet and immunosuppressant drugs.

"Individuals with phenylketonuria [a condition preventing your body from breaking down a specific type of amino acid] should avoid it too, due to its high protein content," she says.

Does the future look green?

Still wanting to jump on the spirulina bandwagon? Greenfield predicts the popularity of this so-called superfood will go through phases, depending on media promotion, and future research around its claimed health benefits. If half the claims around this powder are scientifically proven to be true, it will likely be sticking around.