Spirulina is not a new foodstuff. It was a regular part of the diet of the Aztecs, who know it as tecuitlatl. You might know it better as blue-green algae, or as the body mass of cyanobacteria if you’re a marine biologist.
Spirulina has rapidly become an incredibly popular supplement. It is practically a household name at this point. It is sold as powder to add to shakes, capsules to take with breakfast, and it has even better used to fortify certain foods. Indeed, if you want to start taking this stuff, you now have plenty of options to choose from.
The reason most people take this stuff is because of its supposed nutritional benefits. Manufacturers make much of spirulina’s high protein content, and consumers are lapping it up. Spirulina is also said to be high in numerous vitamins and minerals, which is why it is popular among people with dietary constraints (lactose intolerance, vegetarians, vegans, people with IBS, etc).
But some people go much further. According to some people, spirulina can treat, cure, and prevent a wide range of diseases and conditions. It is variously promoted as a cure for high cholesterol, an effective treatment for malnutrition, and as a preventative measure against ageing.
Obviously, we are highly suspicious whenever people make health claims about unregulated, natural supplements. After all, these supplements are essentially just powdered food. Their ability to affect the progression of serious diseases and conditions is likely to be nil.
What does spirulina really have to offer?
Is it as nutritionally dense as people claim?
What about the health claims? Are they substantiated by empirical studies?
In this article, we’re going to answer each of these questions in turn. We’ll look at the nutritional content of spirulina. We will discuss the benefits and negatives of using it as a dietary supplement. We’ll then go on to examine the health claims made about spirulina, using the available scientific studies as our guide.
Do you use spirulina on a regular basis? How have you found it? Does it work for you? Why do you use it? Please share your answers in the comments section at the end.
Spirulina Nutritional Content
If all anybody ever said about spirulina was that it was high in protein, there’d be no problem.
Spirulina is about 60% protein by weight. That is more protein per gram of food than beef steak, chicken breast, or any nuts. It is actually one of the most protein-dense foods on the planet. A 100g serving of spirulina will give you over 100% of your RDI of protein.
The protein in spirulina is also very high quality. It contains all essential amino acids, making it a complete protein in practical terms (any amino acids it doesn’t give you can be made in the body). This is definitely a rarity among plant-derived proteins. While it isn’t necessary to get all of your protein from complete sources at all, it is still a point in spirulina’s favour.
On top of protein, spirulina is rich in vitamins and minerals. For example, 100g of spirulina would give you 158% of your RDI of iron, 20% your RDI of vitamin C, 70% of your RDI of niacin, 48% of your RDI of magnesium, and 20% of your RDI of vitamin B6.
Spirulina is often said to be high in vitamin B12. But there is a lot of controversy surrounding this. Some people state that the form of B12 in spirulina cannot be used by humans. They either claim that it is not absorbed in the human digestive system, or that we simply can’t use it like we can the cobalamin we normally get from food. However, a study published in 2002 found that the B12 in spirulina is highly bio-available. While we need to see something more conclusive here, we suspect this is another example of supplement company propaganda seeping into the mainstream.
The best thing about all this is that this nutritional bomb is wrapped up in 0mg of cholesterol, very little saturated fat, and a hefty 900mg of omega-3 fatty acids.
So as a nutritional supplement, spirulina actually looks pretty damn good.
It seems to be easy on the digestive system. Allergies appear to be quite rare, although the phenylalanine content means people with phenylketonuria need to stay away.
It is quite cheap, and highly nutritious.
For us, this passes the test. Spirulina is a good quality dietary supplement, useful for people who struggle to get enough protein, iron and omega-3 fatty acids.
But what about the health claims?
If you look at the studies, it’s clear that the health claims made about spirulina are total rubbish.
Bogus Health Claims
The health claims made about spirulina appear to be either over-blown, born of a misinterpretation of data, or completely fictitious.
For example, the claim that spirulina has antioxidant properties is baseless. To our knowledge, there are no in vivo human studies on spirulina’s action as an antioxidant. That’s no studies full stop; forget about studies showing a positive effect!
Another unfounded claim is that spirulina supplementation acts as a quick cure for chronic fatigue. An interesting paper published in Phytotherapy Research in 2007 really put this bogus claim to rest once and for all: “The scores of fatigue were not significantly different between spirulina and placebo. Spirulina administered in a dose of 3 g/day did not ameliorate fatigue more than the placebo in any of the four subjects, and possibly it has no effect on chronic fatigue.” (ref).
Some studies, such as this one, suggest that spirulina has the ability to lower cholesterol levels in the blood. However, like the cited example, these studies have tended to use very small groups with very specific medical conditions. The above study, for example, uses just 15 people, all of whom are living with diabetes. The study was conducted over just two months; typical for clinical investigations into spirulina.
The claims about spirulina and cancer are even more misleading. People have used a handful of studies, such as this one, to promote the idea that spirulina can help prevent or even cure certain types of cancer. Yet there is absolutely nowhere near enough evidence to support such a claim. The above cited study was an unblinded, non-randomized trial. It also looked at the administration of several substances simultaneously, one of which was an algae extract. It is absolutely impossible to use this study to say that spirulina caused the observed regression in leukoplakia.
Anybody telling you that spirulina supplementation can reliably lower cholesterol, reduce chronic fatigue or help the body fight cancer is either lying to you, or they’re just too stupid to understand the available scientific data.
However, it’s not all lies and misinformation with spirulina.
There are some really robust studies out there showing that it has a profound effect on immune system function, inflammation, and more.
What Can It Do?
According to this fascinating study published back in 1997, spirulina supplementation seems to inhibit anaphylactic shock in rats. Human anaphylactic shock has a similar mechanism to that of rats, so in theory, spirulina may help attenuate the severity of allergic reactions.
There is also substantial evidence that spirulina supplementation can help protect against allergic rhinits (ref). It is possible that both of these studies are highlighting a single property of spirulina; what that property is, we don’t know. More work is needed here clearly!
This brought us to a paper published in the journal International Immunopharmacology in 2002. Here, researchers found that spirulina had a direct effect on the innate human immune system. They stated: “In vitro stimulation of blood cells with BCG cell wall skeleton (CWS) allowed more potent IL-12 p40 production in cells from volunteers given Spirulina than in cells without pre-exposure to Spirulina. As BCG-CWS serves as a ligand for Toll-like receptor (TLR) 2 and 4 to raise the maturation stage of monocytes/macrophages, Spirulina may be involved in the signaling responses through Toll in blood cells even when orally administered” (ref).
More research is required before we can start talking about spirulina as a powerful immune system booster. We don’t know how great the effect is, or what it means in terms of disease prevention.
But we can say that spirulina does hold some promise as a general health booster, beyond the fact that it is extremely nutritious.