Probiotics and Resistance to Illness

Seth Roberts

A 2005 study compared workers who did and did not consume a daily straw of probiotic liquid. During the 3-month study, workers who got the probiotics were sick half as often as those who didn’t. Here are details:

262 employees at TetraPak in Sweden (day-workers and three-shift-workers) that were healthy at study start were randomised in a double-blind fashion to receive either a daily dose of 100,000,000 Colony Forming Units of L. reuteri or placebo for 80 days. The study products were administered with a drinking straw. 181 subjects complied with the study protocol, 94 were randomised to receive L. reuteri and 87 received placebo. In the placebo group 26.4% reported sick-leave for the defined causes during the study as compared with 10.6% in the L. reuteri group (p < 0.01). The frequency of sick-days was 0.9% in the placebo group and 0.4% in the L. reuteri group (p < 0.01). Among the 53 shift-workers, 33% in the placebo group reported sick during the study period as compared with none in the L. reuteri group(p < 0.005).

The paper gives no reason to think the probiotic dose was optimal. (How the dose was chosen isn’t explained.) A larger dose might have had a bigger effect.

When science writers tell about the “miracle” of antibiotics, they tell stories like this one, from The Probiotics Revolution (2007) by Gary Huffnagle with Sarah Wernick:

When my daughter was five, she pricked her left hand on a rosebud thorn in our garden. . . . The next day she ran a fever. . . . Doctors diagnosed an acute bacterial infection. Half a century ago, a child might have died from such an infection. But my daughter received antibiotics. After a day of intravenous treatment, she was better. . . . Antibiotics are true miracle drugs.

What goes unnoticed in these “miracle” accounts is the possibility that the person got so sick because their immune system wasn’t working well. (It wasn’t working well, I propose, because the infected person didn’t get enough bacteria in their food.) A child gets sick from an ordinary plant scratch? That child’s immune system has a lot of room for improvement. Huffnagle and Werrick say nothing about this.

Dr. Huffnagle is a professor of internal medicine, microbiology, and immunology at the University of Michigan. If the child of such a parent — well-off, well-educated, health-conscious, specializing in immunology — has a weak immune system, and the parent doesn’t realize this is possible, there is enormous room for improvement.

The Probiotics Revolution is 90% filler but the 10% substance makes it worth skimming.

4 thoughts on “Probiotics and Resistance to Illness”

  1. ‘The Probiotics Revolution is 90% filler’ was my impression also. Some of the useful 10% included:
    (a) study of probiotics is in its infancy (which is why the book is full of ‘probiotics hold promise to solve . . .’ statements)
    (b) about a dozen well-designed experiments are discussued . . . more, please, I’d like to see a book filled with discussions about hundreds of experiments
    (c) dead bacteria still produce benefits . . . why? there appear to be two theories: (1) dead bacteria adhere to the lining of the gastrointestinal tract thus crowding out harmful competitors or (2) the metabolic byproducts of fermentation have benefits. I’m looking forward to seeing this one resolved.
    Many studies are listed at the end of the book, but, unfortunately, as a layman, I have no access to many of them, since most are behind a pay wall.
    I suspect that much of the funding comes from the private sector looking for a magic bullet of probiotics which can be packaged and sold. I wonder if there actually is an ideal combination of specific bacteria, or is it just that the internal system needs to be challenged by a certain amount on a regular basis?
    Also, and this is more of a general gripe with the marketplace, why can’t Dannon Activia and similar products be produced without added sugar or fructose syrup?
    Reply
  2. Kirk said “Why can’t Dannon Activia and similar products be produced without added sugar or fructose syrup?” Well, obviously they can be, but the companies choose to add these junk ingredients because the mainstream American will not select such products to consume without the additional sweeteners. Dannon’s first priority is to sell as many of their products as possible. Fortunately, there is a growing availability of pure cultured products at alternative sources such as Whole Foods, Trader Joes, and at some Farmer’s Markets and other whole-food outlets. I suspect such outlets are not available equally across the US, though.
    Reply
  3. If the book is 90% fluff, how about a Seth Roberts book that’s only 10% fluff! Are you planning a second book and immune theories? I’ll pre-order right now!
    Reply

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