In recent years, Spirulina has taken the health world by storm. Often touted as one of the 'best superfoods' (I hate that term), spirulina’s claim to fame started with NASA including it as a dietary supplement for astronauts during space missions, UN declaring it as the best food of the future, and FDA approving it to be classified as a food.
It did not take long for Spirulina to find its way into consumer products in the form of dietary supplements (tablets, powders, and capsules), and even energy bars, snacks (even popcorn!), smoothies, and health drinks.
Is Spirulina truly this amazing superfood that we should all be including in our daily routine? Results of recent studies seem to offer a contradicting view on whether the risks of contamination from Spirulina overweighs its benefits.
Let’s first take a look at what the craze over Spirulina is all about.
Spirulina and Its Benefits
Often thought of as a type of algae, spirulina is technically a cyanobacteria (bacteria that can photosynthesize). It commonly grows in fresh and saltwater, especially in subtropical and tropical areas of America, Mexico, Asia, and Central Africa.
Nowadays, Spirulina is typically grown commercially in fresh and natural waters like earthen ponds or lakes in or near agricultural areas.
The three main species that have been studied for their nutritional benefits include Spirulina platensis, Spirulina maxima, and Spirulina fusiformis.
Some benefits include:
Spirulina is also often sold as a complete source of protein (containing the essential amino acids) - which is why a lot of vegan/plant-based eaters incorporate spirulina into their diet.
It provides essential fatty acids (particularly gamma-linolenic acid (GLA)) - which are anti-inflammatory and supports healthy skin, nerve, and hormones.
Some studies have also associated Spirulina with anticancer, antiviral and antiallergic benefits though most of these are small and therefore not conclusive.
With a nutritional profile like that, Spirulina does sound like a dream superfood. But are there any downsides and how should you look for a quality product?
Cyanobacteria like spirulina are effective accumulators, which means they accumulate and even concentrate heavy metals from their environment. In fact, spirulina has been used to remove lead in contaminated water in the past! That in part explains why spirulina is often sold as a detox supplement... (psst... don't fall for quick fixes - you know how I feel about most detox supplements 👎)
While this ability is an advantage when it comes to accumulating beneficial trace elements from the environment, it can become a liability when toxic metals are concerned, for instance, when water used in growing spirulina is contaminated by pesticides and fertilizers used in the agricultural areas nearby, or those grown in desalinated Pacific Ocean water near Japan contaminated by radiation from the 2011 Fukushima nuclear disaster.
In this study, researchers tested 25 Spirulina products for six common heavy metals and minerals (Ni, Zn, Hg, Pt, Mg, and Mn) and found trace amounts of these metals and minerals present in each brand tested. However, it was concluded that the levels were lower than the daily recommended intake, and therefore spirulina is safe for us to consume.
Nickel and zinc were the highest amounts of contaminants found in all the brands tested. Both are important nutrients and necessary in the right quantities, when consumed in excess it can have detrimental effects. Excess zinc can throw off copper balance, for example.
In addition, studies have found that metals like lead, mercury, and arsenic are very likely to be present in spirulina products. These could be contributed by industrial pollution, pesticides and agricultural fertilizers, heavy metals in soils in certain regions, and the use of plastic pond linings. These metals can be highly toxic to the body when consumed regularly in unsafe amounts. However, this study showed that, when present, these are not at super high concentrations.
So theoretically, spirulina may also be a source of contaminants if they are not cultivated in a clean environment. Sourcing is EXTREMELY important if you take spirulina regularly.
To help you, we contacted some popular spirulina brands and looked at their certificate of analysis (COA). We compared the lead content here as the levels of other metals reported were within the specification levels stated.
NOW, before we look at levels, a little word about prop 65 and heavy metals. Heavy metals are in EVERYTHING. Yeah I know, it's sad and depressing. But this is the reality of how polluted our world is. It's important to get your mindset right around this so you are not always living in fear when the headlines come.
Here are some figures taken from the FDA total food study, https://www.fda.gov/media/77948/download, via Premier Research labs website:
Rather than let it terrify me and make me worry about everything I'm eating, I'm using this information to empower me to make better choices and to remind myself that it is the total body toxic burden that matters.
One food, one powder, one supplement is not going to make or break my health. We have detox organs, and even if something DOES exceed the prop 65 limit, it's not an automatic hard pass for me. I ask myself these questions:
a) Do I need this product? What benefits does it bring me?
b) What happens if I don't take it?
c) Can I find a product that's 'cleaner' easily?
I have clients taking supplements with the Prop 65 label on it - and it is because the benefit outweighs the risks. I help them support their detox organs so we can relax about these unavoidable exposures.
Overly worrying and being obsessive is also 'toxic', and we need to feel safe in order to heal. You got this. Support your detox organs every day to help your body eliminate unavoidable exposures.
OK, not that's out of the way, let's move on to those COAs.
The thing to note when you look at COA's, is that many companies try to manipulate data by quoting super small serving sizes (Look at column 2 and how different these recommended serving sizes are for each brand). For reference, 1 tsp is about 4g, so 1g is basically 1/4 tsp - most people consume more than that.
When we standardized the serving to 3g (just shy of 1 tsp), a totally different story emerges. Look at the numbers in the last column... I highlighted the ones ABOVE prop 65 limit for lead in red:
^ The range is based on the results of several batch testing provided by the company.
* These companies conduct batch testing and have indicated that COA for specific batch purchases can be requested by customers.
We have also reached out to popular green powder blends that contain Spirulina such as Organifi Green Juice Blend, Amazing Grass Green Blend (did not share with us), and Athletic Greens (did not share with us). Organifi Green Juice Blend responded with their test result (which is available on their website). The results of several batches tested showed a wide range of lead content (0.74 – 1.52 mcg/serving), above the prop 65 daily limit of 0.5mcg/day. Interestingly, they put an asterisk next to these numbers on their website but I don't know what this means as there was no footnote.
I am not here to tell you what to do. The prop 65 limits ARE very stringent, and it's pretty hard to stay below their limits with our soils so polluted now. So you have to make that call for yourself and weigh up the pros and cons. These products may benefit you, but it never hurts to be informed and armed with knowledge so you can make that decision for yourself.
Heavy metals are not the only toxin we should be concerned about when it comes to Spirulina. Microcystin is a type of toxin produced by cyanobacteria in freshwater lakes and rivers. While Spirulina typically contains non-toxic cyanobacteria, the presence of toxin microcystin can slip through the cracks when there isn’t proper quality control. In the past, this has been found to occur regularly in those grown in the Upper Klamath Lake, Oregon, which contaminated Spirulina during harvesting.
In a study testing 18 different Spirulina products, researchers found that 8 of the products contained microcystin, and four products contained toxin amounts exceeding the recommended daily limits. They don’t list the exact brands tested, but they do mention where the brands were found.
Of all the COAs we’ve reviewed, microcystin level was only reported by Nutrex Hawaiian Spirulina Powder and Blue Majik E3Live frozen AFA, both of which reported levels below the limit specifications.
Nutritionally, chlorella and spirulina are comparable, with spirulina containing slightly higher protein, GLA, Vitamin B12, iron, and zinc, while Chlorella is higher in calories and richer in omega-3 fatty acids, Vitamin A, B2, chlorophyll, and less of a concern with iodine (though it is still a good idea to run this by your doctor first if you supplement).
Unlike spirulina which can be consumed once harvested, chlorella has to go through processing to break its cellular walls to make it bioavailable for humans. And while Chlorella is not a cyanobacteria but rather an alga, it is still exposed to the same risks of contamination as Spirulina, hence the same considerations we’ve discussed above should apply.
How about seaweed?
Seaweed or sea vegetables, another marine macroalgae that offers a great source of essential minerals, vitamins, and antioxidants due to its high absorption capacity, are also exposed to the risk of accumulation of toxic metals (like arsenic, cadmium, copper, mercury and lead) from its environment. In a study of edible seaweeds consumed in Europe, the highest levels of cadmium, lead, aluminum, and mercury contents were found in seaweeds from Asia and Europe. Again, the total exposure to these contaminations depends on the type of seaweed and your overall consumption. Maine Coast Sea Vegetables offer useful information on this and provide testing information on a variety of sea vegetables, I like this brand for sea vegetables.
No doubt spirulina has a very impressive resume, but it does come with a hefty price tag, in many ways. For those with thyroid issues, on medications, children, pregnant women, and those with health conditions especially autoimmune disorders, I recommend checking with your doctor first.
I don't regularly have spirulina, because I eat a lot of seaweed and dulse. However, if I was to buy one, my choice would be the E3Live Blue Majik* for the lower lead level and the fact they tested for microcystin. Nutrex Hawaiin would be another good one, and if Terrasoul tested for microcystin, that would also be one of my choices.
*Just because one product is good from a brand, doesn't mean all their products are good. Make sure you look at the COA of whatever you are taking regularly in large quantities and get an updated one every 6 months in case they change suppliers.
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**Other brands we’ve approached but did not respond or declined to provide their COA include Earthrise Spirulina Natural, Sunfoods, Micro Ingredients, and Sari Foods.