Why African children have big belly?

Answer 1

* malnutrition, and African children are not the only ones*

Let's first have a glimpse at the circulatory system of the human body, as the ''big belly'' is closely related to it.

The circulatory system is made up of the plasmatic environment (the liquid part of the blood, in the different vessels of our body) and the interstitium (the liquids that surround the many cells that compose the tissues of our body), and many exchanges of liquids occur between these. One of the physical processes that allow these exchanges is called ''oncotic pressure'', which is basically a kind of osmotic pressure between capilaries and tissues. It causes the movement of water towards high-protein environments. If there are more proteins in your blood than in your interstitium, water infiltrates the plasmatic environment (because of the oncotic pressure). If there are less proteins in your blood than in your interstitium, water infiltrates the interstitium (once again, because of the oncotic pressure).

Then, what links the circulatory system with the characteristic belly of (not exclusively)african children? Well, since a lot a these kids are raised in poor living conditions, they suffer malnutrition. They don't eat enough and they don't get all the nutrients they should, in particular proteins! Thus, their blood contains a very low amount of proteins and the oncotic pressure promotes the movement of liquids from the blood to the interstitium. And since the level of proteins in their blood rarely stabilizes, fluids accumulate in their tissues and they develop a large belly.

(Source: I'm a med student)