In the New York City subway, I noticed a series of advertisements from a bedding company called Brooklinen. One advertisement had a surprising claim, which I found again on their website:

The average 2-year-old pillow contains 17 species of fungus.

I was a bit skeptical of this, so I did some digging.

My research so far

Brooklinen did cite a source: Mercola.com, which in turn linked to the website of the University of Manchester, though I was redirected away from the page and couldn't find anything else through the university. Mercola.com's version of the claim was a little different:

When researchers tested samples of pillows, which had been used anywhere from 1.5 to 20 years, they found several thousand spores of fungus per gram of pillow, which means any one pillow could contain more than 1 million spores.

Up to 16 different species of fungus, from varieties found in bread to varieties common in showers, were detected in the individual samples. Pillows made from synthetic materials tended to have higher levels, which is another reason why pillows made from natural wool are preferable.

I found what I think is the paper, Fungal contamination of bedding (Woodcock et al. 2005) (from researches affiliated with the University of Manchester), and it seems like it matches the summary on Mercola.com decently well. There are two key differences between the paper's conclusions (based on a sample of 10 pillows) and Brooklinen's claim:

  • None of the samples contained 17 species of fungus; they contained anywhere from 4 to 16.
  • The samples occupied a wide age range, from 1.5 years to over 20 years.

The point is, as far as I can tell, the study doesn't match Brooklinen's claim at all, unless I'm misreading it. The supposed number of fungus species found is different, as is the pillow age. It's different enough that I'm wondering if I found the wrong paper and Brooklinen is basing their claim based on some other data. It left me quite confused.

The question

Is there any merit, then, to Brooklinen's claim? Does the average two-year-old pillow really contain 17 distinct species of fungus?

  • 14
    i'm very sceptical it's only 17. Fungi are a varied and hardy lot. – bukwyrm Jul 29 '19 at 4:47
  • 9
    The bigger question is whether the claim, if true, tells us anything useful. If (hypothetically) an entire pillow had only 17 individual mold spores in it, and each of those spores happened to be of a different species, it would satisfy the claim. And yet, I would consider such a pillow mold-free for all practical purposes. – plasticinsect Jul 29 '19 at 4:51
  • 1
    @piojo As far as possible, it's best to treat each claim and piece of evidence on its own merits. The fact that someone has previously published research which has been debunked would be at most a small supporting point within an answer, and would itself need to be well-referenced to avoid just being opinion. – IMSoP Jul 29 '19 at 12:36
  • 7
    How many species of fungus are in a brand new pillow? – James Jenkins Jul 29 '19 at 13:41
  • 6
    This isn't an answer but perhaps could guide one, but scores of species of fungus live on our skin: ncbi.nlm.nih.gov/pmc/articles/PMC3711185 As other people have mentioned 17 is probably both a low estimate and no serious cause for concern. – Thegs Jul 31 '19 at 15:06

Brooklinen has now removed the claim (which now redirects to Brooklinen's home page). An archived version of the claim is here.

  • I don't want to go into any of my numerous interactions with Brooklinen CS in this answer. The first CS agent promised to send me a source by email afterwards; this source mentioned the same study as Mercola. The second CS agent promised to follow-up with me after asking the team. The follow-up email never came as promised. This agent was dismissive of my questions about the Sleep Fact after my pointing this out. "I can definitely forward your concern about the Sleep Fact. Do you have a specific concern about one of our products?" The third agent directed me to his supervisor. – Barry Harrison Aug 24 '19 at 1:34
  • Supervisor sent the email quoted in the answer and didn't help. I also emailed hello@brooklinen.com 3 times, without any replies. I suspect the CS team at Brooklinen is small; in my most recent contact, Brooklinen CS recognized my question without my asking. I have asked for an email from Brooklinen CS stating they cannot find a reputable source if this is the case or a reputable source if they can find one. I do not expect any further information from Brooklinen. – Barry Harrison Aug 24 '19 at 1:36
  • 1
    I appreciate the investigative effort you've put in, but right now, your answer doesn't address the claim within site guidelines. It's somewhere between original research and naa. – fredsbend Aug 24 '19 at 15:15
  • If no one is making the claim anymore, I wonder if we have notability issues now. – fredsbend Aug 24 '19 at 15:16
  • 1
    @fredsbend Thinking about the question again, I still believe the claim is incorrect. – Barry Harrison Aug 24 '19 at 19:17

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