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Revised Estimates for the Number of Human and Bacteria Cells in the Body

PainSci » bibliography » Sender et al 2016
Tags: biology, neat, fun

One article on PainSci cites Sender 2016: Vitamins, Minerals & Supplements for Pain & Healing

PainSci notes on Sender 2016:

You may have heard that the human body is infested with ten times as more bacterial hitchhikers than the number of our own cells, and even that they have equal mass. Happily, no, we are not quite that disgusting. There’s “only” about the same number of bacteria as the headcount for our own cells, and — because bacteria are quite a bit smaller than our cells — they weigh just a couple hundred grams on average.

original abstract Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

Reported values in the literature on the number of cells in the body differ by orders of magnitude and are very seldom supported by any measurements or calculations. Here, we integrate the most up-to-date information on the number of human and bacterial cells in the body. We estimate the total number of bacteria in the 70 kg "reference man" to be 3.8·1013. For human cells, we identify the dominant role of the hematopoietic lineage to the total count (≈90%) and revise past estimates to 3.0·1013 human cells. Our analysis also updates the widely-cited 10:1 ratio, showing that the number of bacteria in the body is actually of the same order as the number of human cells, and their total mass is about 0.2 kg.

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