Last week I glimpsed a Facebook ad for “nature’s perfect superfood”, Chlorella, a freshwater green algae that grows naturally in certain parts of Asia.
Every single time I hear the term “superfood”, this happens:
There are two reasons for that.
1. Sure, certain foods are nutrient-dense, but foods slapped with the prefix “super” usually turn out to be plain old food, neither more nor less healthful than other foods in the same category. For instance, acai berries were hailed as a superfood and an anti-aging aid due to their high levels of antioxidants, but researchers have pointed out the berries contain about the same amount of antioxidants as other (far less expensive) fruits like blueberries and grapes. (1) Thanks to the trendiness of acai products, rural Brazilians who rely upon the berries as a staple food find their stomachs grumbling. (2)
2. You probably don’t need dietary supplements if you are healthy and have a varied, nutrient-rich diet. Certain foods or supplements might be beneficial when you have a deficiency, but if you don’t have a deficiency, you will get little to no benefit from them. (3)
What does Chlorella supposedly do?
An incredibly broad range of claims has been made about the health benefits of Chlorella. In addition to being hailed as a nutrient-dense superfood (example), a detoxifying agent, and an energy booster, one Japanese study suggests it can:
– reduce body-fat percentage
– alleviate Type 2 diabetes by reducing blood-glucose levels
– help reduce cholesterol (4)
Many, many scientifically unsupported claims are being made about Chlorella. It can supposedly aid digestion by stimulating the growth of probiotic bacteria, treat ulcers, alleviate depression, increase “liver energy”, prevent or even cure cancer, and “boost immunity” (which would be a bad thing, if your immunity is normal).
Does it work?
As a food source? Yes (see “The Bottom Line” at the end of this post). As a cure-all pill, diet aid, or detoxifying agent? Probably not.
The problem with the bulk of the recent research involving Chlorella is that the results have not yet been replicated. When the Telegraph breathlessly tells you Chlorella can “reduce body-fat percentage”, they’re not telling you that this was found in just one study. (4)
At one time, Dr. Joseph Mercola claimed Chlorella could “fight cancer”. As absolutely zero evidence supports this, and federal law prohibits supplement suppliers from making health-related claims for their products, the FDA ordered Mercola to stop making that claim (and several others) on his website. So then he switched to saying Chlorella could eliminate your risk of getting cancer. The FDA ordered him to stop saying that, as well. Has this prevented Mercola from making extravagant claims about the curative properties of Chlorella? Nope. These days, he declares it can “prevent or ease” everything from stress to liver cancer. (5)
A lot of woo has attached itself to Chlorella over the years. Erich Von Däniken of “ancient astronauts” fame proposed in his 1980 book Signs of the Gods that maybe the Ark of the Covenant was a miniature nuclear reactor and manna machine. According to this theory, the “ark machine” absorbed and stored dew, to which green algae (Chlorella) was added, and poof! Delicious manna came out of the machine. It would have been radioactive as hell, but meh. Logic is for the unimaginative.
Not that Von Däniken was being particularly imaginative; he borrowed the entire “alien manna machine” concept from an April Fool’s article in New Scientist, which later became a book.
One health blogger says she’s taking Chlorella to “detox heavy metals” that supposedly remain in her body from chemotherapy she received some time ago. This is not a sound decision. First of all, heavy metals can be eliminated from the body only if treatment is administered immediately after exposure. Secondly, nothing in Chlorella has been shown to remove metals from the body. Thirdly, there is only one heavy metal involved with chemo (platinum, found in the chemo drugs Carboplatin and cisplatin). The platinum from both drugs generally remains in cells for up to 180 days. (6) Even if Chlorella could bind heavy metals, it would be incapable of removing them from the tissues and bloodstream without the aid of chelation. (5)
The Bottom Line
So, Chlorella manna and Chlorella “metal detox” are bunk. But is Chlorella a superfood? In the ’50s and ’60s, scientists thought it could be. After WWII, the Baby Boom led governments around the world to study Chlorella in the hope it could be used to feed the masses cheaply and efficiently in the event of food shortages. NASA studied it with a view to feeding it to astronauts, and perhaps growing it on space stations. But processing Chlorella for consumption turned out to be too costly and time-consuming for either purpose, and it was relegated to the dietary supplement shelves of health food stores. It is an excellent food source. In its dried form, Chlorella is 45% protein, 20% carbohydrate, 20% fat, 5% fibre, and 10% vitamins and minerals. It contains nine essential amino acids. (7)
But according to an article on Chlorella at WebMD, the quality of the Chlorella found in supplements can vary wildly. The Chlorella in some products may contain only 7% protein, for instance.
To become a supplement, Chlorella is dried , crushed to a powder, and converted to small emerald tablets, which are vaguely reminiscent of Soylent Green. If the cell walls remain intact – and there are indications that this is the case with some Chlorella supplements – the Chlorella will be of no benefit to humans.
The recommended daily dosage for one of the most popular brands of Chlorella tablet is 15 tablets per day, at about $34US per 300 tablets. Perhaps this makes sense if you don’t have access to fresh, inexpensive greens like kale, but for the average consumer this is a pretty penny to spend on what are essentially veggie pills. A diet with sufficient carbs, protein, and vitamins will not require Chlorella.
1. – Kuskoski EM, Asuero AG, Morales MT, Fett R, et al. “Wild fruits and pulps of frozen fruits: antioxidant activity, polyphenols and anthocyanins”. Cienc Rural 36 (July/August 2006)
– Seeram NP, Aviram M, Zhang Y, et al. “Comparison of antioxidant potency of commonly consumed polyphenol-rich beverages in the United States”. Journal of Agriculutral Food Chemicals 56 (February 2008). (abstract)
2. “‘Superfood’ Promoted on Oprah’s Site Robs Amazon Poor of Staple” by Adriana Brasileiro, Bloomberg, May 14/09
3. Brown University’s page on nutrition supplements
4. T Mizoguchi, I Takehara, T Masuzawa. “Nutrigenomic studies of effects of Chlorella on subjects with high-risk factors for lifestyle-related disease“. Journal of Medicinal Food 11:3 (Sept. 2008)
5. “Dr. Oz Revisited” by David Gorski, Science Based Medicine blog, Feb. 7/12.
6. Elke EM Brouwers, Alwin DR Huitema, Jos H Beijnen, Jan HM Schellens. “Long-term platinum retention after treatment with cisplatin and oxaliplatin“. Clinical Pharmacology 2008, 8:7.
7. Belasco, Warren. “Algae Burgers for a Hungry World? The Rise and Fall of Chlorella Cuisine”. Technology and Culture 38:3 (July 1997). Available from Jstor.