This weekend I have been tweeting and posting about the Microbiome Medicine Summit, an online collection of talks by self-proclaimed “microbiome experts”. Some of these were MDs, some were PhD’s, and many others had titles I had never heard of before, but there was not a lot of science or medicine that was discussed here. In fact, a lot of the talks I listened to tried to first scare people about ingredients in their food or bad bugs in their guts, immediately followed by a mention of the speaker’s book or online cleansing products that the audience should buy.

As an example of this scare tactic, I found a disturbing “factoid” on the website of Ann Louise Gittleman, who calls herself the First Lady of Nutrition (although I think that Michelle Obama is way ahead of her!). ALG held one of today’s Microbiome Summit talks called “Parasites May be the Hidden Cause of Your Health Issues”. You can find my transcript of parts of her talk here.

In her talk, ALG mentioned that a large part of the US population are infected by parasites. She mentioned that her mentor parasitologist estimated that 1970’s this number was 8 out of 10 Americans. She also claimed that most stool tests won’t detect these parasites. They are so hidden inside our guts, she said, that a regular stool test will easily miss them. But they are there! Anyone with GI problems, diarrhea, constipation, gas, GERD, or even sleep problems, Crohn’s Disease, asthma, arthritis and pretty much anything else you can think off, all these symptoms, she says, are an indication that you are infected with parasites. She even went on to say that these parasites are easier to detect “4 days before and after a full moon.”

So this is the point where she lost all my sympathy. She is really trying to scare the audience by telling them that pretty anyone is infested with invisible and undetectable parasites. But low and behold, she offers a solution (I am sarcastic here). You can go to her website where she sells a product called “My Colon Cleansing Kit“. And it’s even for sale! For $96 you will get 3 jars of herbs and probiotics.

But here is what caught my eye. On the Details tab, she writes the following:

A study in The American Journal of Tropical Medicine and Hygiene found that 32% of a nationally representative sample of the US population tested positive for parasites. From microscopic organisms to 15-foot tapeworms, intestinal parasites can cause weight gain, damage organs, create toxicity, and infiltrate the bloodstream and brain. Parasites are often overlooked, however, because their symptoms can mirror other illnesses.

Oh, that is scary. It sounds like she is writing that one third of the US populations is infected with parasites, right? Don’t you already feel a bit itchy down under? Could these invisible parasites you never realized you had be the cause that you don’t feel so well lately?

But is it really true? I guess I am a skeptical scientist, so I did not immediately believed this. So I dived into the American Journal of Tropical Medicine archives to dig up the study that she forgot to properly cite. It took me some ninja Google skills, but I found the study. And here it is, the real science behind ALG’s statement:

Seasonal prevalence of intestinal parasites in the United States during 2000 – Omar M Amin – Am J Trop Med Hyg June 2002 vol. 66 no. 6 799-803

Abstract: One-third of 5,792 fecal specimens from 2,896 patients in 48 states and the District of Columbia tested positive for intestinal parasites during the year 2000. Multiple infections with 2-4 parasitic species constituted 10% of 916 infected cases. Blastocystis hominis infected 662 patients (23% or 72% of the 916 cases). Its prevalence appears to be increasing in recent years. Eighteen other species of intestinal parasites were identified. Cryptosporidium parvum and Entamoeba histolytica/E. dispar ranked second and third in prevalence, respectively. Prevalence of infection was lowest (22-27%) in winter, gradually increased during the spring, reached peaks of 36-43% between July and October, and gradually decreased to 32% in December. A new superior method of parasite detection using the Proto-fix-CONSED system for fixing, transport, and processing of fecal specimens is described. In single infections, pathogenic protozoa caused asymptomatic subclinical infections in 0-31 % of the cases and non-pathogenic protozoa unexpectedly caused symptoms in 73-100% of the cases. The relationship between Charcot-Leyden crystals and infection with four species of intestinal parasites is examined and the list of provoking parasitic causes is expanded.

After reading the whole paper here’s my scientific interpretation: Yes, it is true that one third of the tested patients (916 of 2896) tested positive for at least one parasite. But here is the catch: it says *patients*. Every word in a scientific paper should be read carefully and is probably important. These were patients. These were not healthy people. All these samples were sent in by a physician to a specialized parasitic center for parasitic evaluation. In other words, their doctor suspected that their patients might have a parasite, based on e.g. a combination of GI complaints and recent travel to a foreign country, which about half of them had done.

So instead of writing that one third of the US population tested positive for parasites, it should read “One third of US patients suspected to be infected with a parasite indeed were found to be infected with a parasite. ” That is very different than the general population, where the real percentage is probably orders of a magnitude lower.

It’s just sad that people who are not trained to carefully interpret science are tweaking research findings to fit their own plan – and to fill their own pockets. It is even more sad if these persons are trying to attract people with chronic disorders such as arthritis, Crohn’s disease, and autism. That is just flat-out misleading and quackery. Please don’t fall for this.

Fun fact: Quackery means “the promotion of fraudulent or ignorant medical practices” (source: Wikipedia). It is derived from the Dutch word “kwakzalver”  meaning something like “a person who tries to sell ointments (“zalven”) that probably won’t work”. The Medieval word quack referred to the sound a duck or frog makes, but was also used to refer to exaggeration or overstatements (source: EtymologieBank).

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