In the science communication business, we call them “weasel words.” Why? Because weasels have a reputation for being sneaky and tricky. We are talking about words like “may,” “suggest,” “possible” and “potential” that can trick the reader into forming a positive impression without making a specific commitment. What prompts this discussion about dodgy words? I just finished reading a short article, 850 or so words, about the health benefits of “blue spirulina” on “Healthline,” a reasonably reputable newsletter. I counted the number of times the word “may” appears. An astounding 21 times! The words “suggest,” “possible” and “potential” show up 15 times.
Yes, spirulina “may” have cardiovascular benefits, it “may” benefit the brain, and it “may” reduce the growth of certain bacteria. But then again, “may not” can just as well substitute for “may.” A study can “suggest” an antidiabetic effect for blue spirulina, a “possible” benefit for the immune system, and a “potential” to reduce plaque buildup in the arteries. Here too, ambiguity rules. If one looks over the article with a less critical eye, it is easy to gloss over the weasel words and come away with the impression that spirulina “is” indeed the “superfood” that it is often touted to be.
What we would like to see in a scientific study are statements like “has been shown to,” “has been proven to” or “evidence demonstrates,” but these are elusive when it comes to the claimed benefits” of blue spirulina. But for one exception. Thanks to its content of phycocyanin, it is indeed blue and has been proven to be an effective food dye. That plays well these days with the industry moving to replace what are derogatorily called “petroleum-based dyes” with natural ones.
What is blue spirulina to start with? Before we get to that, what is spirulina? Google will state that it is a type of “blue-green algae.” That is actually a misnomer. Spirulina is better described as a type of bacteria, specifically “cyanobacteria” from the ancient Greek word “kyanos” for “blue.” These bacteria are like microscopic plants in the sense that they can photosynthesize, that is take up carbon dioxide and water and convert these into sugar and oxygen. Cyanobacteria are found in ponds, lakes, rivers and the ocean where they produce a significant amount of the oxygen we breathe. When they burst into “bloom,” they can colour the water green. That “green” is due to chlorophyll, the pigment needed to capture the light energy required for photosynthesis. “Blue spirulina” is an extract of spirulina that contains mostly phycocyanin and few other nutrients.
I first became acquainted with “blue-green algae” in the 1980s when an article appeared in that epic scientific publication, “The National Enquirer,” claiming that phenylalanine, an amino acid found in blue-green algae is an appetite suppressant, and that pills formulated with spirulina, were “all natural and safe.” That phrase always irks me because it implies that natural means safe, which it certainly does not. Spirulina does turn out to be safe, as evidenced by it being harvested from lakes by ancient civilizations like the Aztecs to serve as food. Due to its high nutritional value, its light weight, and its ability to be grown in space, NASA has used spirulina as a dietary supplement for astronauts. For us earthlings, kale, spinach or quinoa have a similar nutritional profile at a fraction of the cost.
As far as phenylalanine suppressing the appetite goes, there was a study in 1980 that found phenylalanine reduced food intake in humans by triggering the release of the satiety hormone cholecystokinin (CCK). Subjects who ingested 10 grams of phenylalanine ate significantly fewer calories and reported feeling fuller compared to those who took a placebo. This suggested a physiological role for CCK in human appetite regulation. However, the amount of phenylalanine found in the spirulina “diet pills” was a few milligrams and would have had no effect whatsoever.
Whole spirulina is rich in protein, about 60% by weight. It also contains beta-carotene, zeaxanthin, lutein and various polyphenols, all of which along with phycocyanin have antioxidant properties. Antioxidants in general have been associated with improved cardiovascular health, anticancer effects, better immune function, reduced oxidative stress on the brain, better cognitive function, lower cholesterol, reduced inflammation and less muscle damage after exercise. However, as far as spirulina goes, these effects have only been demonstrated in cell cultures and animals.
There are two conditions in which benefits of spirulina have been shown through clinical trials. Symptoms of allergic rhinitis, commonly known as “hay fever,” improve, and blood glucose levels decrease in diabetics with the consumption of 4-8 grams of spirulina with a meal. This is only of academic interest because there are better treatments for both rhinitis and diabetes. “Blue algae,” basically a phycocyanin-rich extract, has not been shown to have such effects, although one clinical trial produced a self-reported reduction in chronic pain after taking 1 gram a day for two weeks. That trial was small and the fact that it was sponsored by the manufacturer raises an eyebrow.
Today, spirulina is grown in large industrial vessels and is sold as tablets, capsules and powders. Reputable producers test for microcystins, toxins that can sometimes be present in blue-green algae. The usual marketing claims are that spirulina is nutrient dense, high in protein and possesses significant antioxidant activity. However, there is nothing magical here, anyone consuming a decent diet has no need of spirulina. Whatever health effects it “may” produce would require about 8 grams a day at a cost of about two dollars. Pseudoscientific claims about boosting the immune system, detoxifying the body, producing mental clarity, and increasing energy can be safely ignored. As far as blue spirulina is concerned, it will produce a nice blue colour when added to a smoothie but that’s about it. Note that the last sentence says “will” not “may.”
