Our body has 28,000 billion cells

The big count was done, by cell type, throughout the body in women, men and children. Cells weigh two thirds of our weight. Children have more neurons than adults…

There are 28 trillion cellsthroughout our body. Mathilde Fontez, editor-in-chief of the scientific magazine Epsiloon tells us today how a team of biologists decided to count all these cells in our body.

franceinfo: How was this count carried out and why?

Mathilde Fontez: Yes, German, Canadian and American mathematicians, cancer specialists, medical and biological researchers joined forces to carry out this great census. They studied 1,500 scientific publications to collect all the available data on the number of cells – these basic building blocks of life, which constitute our body.

And the total number they find is astronomical, literally – it’s 1000 times more than the total number of galaxies in the universe: 36,000 billion cells for a man, 28,000 billion for a woman, and 17,000 billion for a child. On average of course, the study gives representative profiles… Ultimately, our cells are two thirds of our weight – the rest is fluids, proteins and minerals.

Have the researchers gone into detail about the different cell populations?

Yes, they detailed 400 types of cells, from small red blood cells to enormous nerve fibers. And besides, what they highlight is that it is the blood cells which are by far the most numerous. For example, as a woman, we have 20 trillion red blood cells and platelets in our blood – but only 250 billion skin cells.

Our spleen is also well equipped with cells: approximately 1300 billion; just like our bone marrow: 1500 billion. Whereas we only have 200 little billion cells in our respiratory system, or only 150 billion in the brain. The proportions are the same for men, even though they have more red blood cells and platelets. Children have more white blood cells and neurons.

Why carry out this count?

The goal of the researchers is first of all fundamental: it is about drawing up the first complete portrait of the body at the cellular level, giving a vision of our organism as a whole – of all our small functional units. But also, of course, to make this data available to the scientific community, in the hope that it can inform medical research.

For example, researchers find many more lymphocytes, these immune cells, than previous studies – 4 times more. What does that mean ? Could this play on the dynamics of certain diseases such as leukemia or HIV? This is an avenue worth exploring.