Spirulina is a form of blue-green algae classed as cyanobacteria. Spirulina evolved over 3.5 billion years ago as the first successful life form on earth. Spirulina now flourishes in warm, alkaline lakes and is a popular health supplement with many nutritional and health benefits. A similar green algae, Chlorella, is more difficult to cultivate and loses much of its nutritional value during processing, so is now less widely used.
Spirulina nutritional benefits
As the basis for the development of life on earth, algae are one of the most bioavailable foods for the human body. Spirulina is an excellent source of over 100 easily assimilated nutrients including antioxidants, vitamins, minerals, enzymes, gammalinolenic acid, iron and chlorophyll.
Spirulina consists of up to 70% protein which is present in the easily absorbed form of glycoproteins, rather than the lipoproteins found in most other protein food sources. Spirulina provides all 9 of the essential amino acids, plus 9 non-essential amino acids – the only ones that are missing are glutamine, asparagine and selenocysteine, which can be made in the body.
Gram for gram, blue-green algae are also the richest natural source of carotenoids, containing more natural betacarotene than carrots.
Although Spirulina is a vegetarian source of vitamin B12, it is mostly present in a form (pseudo B12) that does not affect vitmain B12 status, so for vegans another source of vitamin B12 supplementation is needed.
As a nutritional powerhouse, Spirulina also has a prebiotic effect, promoting the growth of beneficial probiotic bacteria in the gut.
With all these nutritional benefits, it’s not surprising that NASA and the European Space Agency are researching how to incorporate Spirulina into the diet of astronauts.
Spirulina health benefits
Spirulina are widely taken to improve bad breath (halitosis), aid digestion and to detox. Substances extracted from blue-green algae have effects in laboratory cells that suggest they may have beneficial effects against cancer, diabetes, coronary heart disease, degenerative disease, heavy metal toxicity and radiation poisoning. They may also have an immunosuppressant effect against abnormal cell proliferation which is still under investigation.
Spirulina and weight loss
A recent study assessed the effects of adding 500mg Spirulina extracts, twice a day, to the normal diet of 64 obese people compared with placebo pills containing starch.
Those taking part were asked not to make any other changes to their normal diet. Those taking Spirulina reported significantly reduced appetite and, after 12 weeks, lost significantly more weight (1.1kg versus 0.6kg), had a significantly lower body mass index (BMI) and reduced total cholesterol than the placebo group – even though they were not following a weight loss diet. The researchers concluded that taking 1g Spirulina supplements a day for 12 weeks may help to control and prevent obesity and obesity-related disorders.
Another study, involving 40 people with high blood pressure, found that taking 2g Spirulina per day for three months, with no no other changes to usual diet and exercise, was associated with a 5kg weight loss, while those taking placebo gained 2.1kg in weight over the same period.
If Spirulina suppresses appetite and can promote weight loss on its own, it may well improve weight loss when combined with a slimming diet.
Spirulina and blood pressure
In a study involving 40 people with high blood pressure, on medication, half took 2 g Spirulina per day, and half took placebo for three months. At the end of the trial, those taking Spirulina showed a significant reduction in blood pressure of 6/5 mmHg, while in those taking placebo, blood pressure increased. This effect may partly be due to the associated weight loss, but the elasticity of their arteries (endothelial function) also improved due to effects on nitric oxide, which dilates arteries.
Spirulina and exercise performance
Spirulina is a popular nutritional supplement among athletes for its antioxidant and performance-enhancing effects.
A small study involving 9 moderately trained males tested their exercise performance on two separate occasions after they took 6g Spirulina per day for 4 weeks, or placebo for 4 weeks. After running on a treadmill for 2 hours, the pace was dramatically increased. Their time to fatigue after the 2 hour run was significantly longer after taking the spirulina supplements (2.70 minutes compared with 2.05 minutes with placebo.
After taking Spirulina. the rate at which they oxidised fat during their 2 hour run increased by 10.9%, while the rate at which they oxidised carbohydrate decreased by 10.3% compared with the placebo trial. This suggests that Spirulina supplements promote a significant increase in exercise performance and fat oxidation.
Spirulina and fatigue
Spirulina is used to overcome physical and mental fatigue. This effect was tested in a group of men with work-related fatigue. After 1 week, those taking 3 g Spirulina per day had a small, but statistically significant increase in calories burned during exercise on a cross trainer machine, and showed improved performance in a math based mental fatigue test. Their subjective sense of physical and mental fatigue improved within 4 hours of taking the first supplement and was still present 8 weeks later.
Spirulina and allergies
Spirulina has beneficial effects on immune function that has been found to improve symptoms of allergic rhinitis such as nasal discharge, sneezing, congestion and itching, compared with placebo.
Spirulina and leukoplakia
A trial involving 44 people with precancerous lesions of the mouth (oral leukoplakia) who took 1 gram Spirulina per day for one year, the lesions vanished in 45% of those taking Spirulina compared with only 7% of those taking placebo.
Spirulina and detox
Spirulina has a chelating action that binds toxins in the digestive tract (eg heavy metals) and promote their removal from the body. Spirulina has been used to help treat chronic arsenic poisoning. A blue pigment, phycocyanin, found in Spirulina can also reduce kidney damage due to heavy metals such as mercury.
The recommended dose of Spirulina varies from product to product, but is typically 1g to 6g a day. Larger amounts may be consumed as a food without apparent harm. Spirulina supplements are best taken with food.
Select a recognized, mainstream brand of Spirulina, preferably one that is certified organic which means it has grown in unpolluted waters.
Spirulina side effects
A few people taking Spirulina have reported mild side effects such as headache, flushing and sweating.
Blue green algae contain the amino acid, phenylalanine, which can cause adverse effects in people with a genetic metabolic abnormality called phenylketonuria.
Algae harvested from the wild rather than grown under controlled conditions may, potentially, be contaminated with toxic algae or pollutants such as heavy metals, which has been associated with diarrhoea, vomiting and liver damage.