The most common elements in our solar system are hydrogen, helium, oxygen, carbon, and nitrogen. Hydrogen makes up roughly 91% of our solar system and helium makes up a bit less than 9%. All the other kinds of elements add up to less than 2 out of every 1000 atoms in our solar system. Hence the joke that the astronomer’s periodic table has three elements: hydrogen, helium, metal.
The “metal” elements of the top five (oxygen, carbon and nitrogen) aren’t numerous overall, but if you pick any 10 “metal” elements in the solar system, about 6 will be oxygen, 3 carbon, and 1 nitrogen.
But here’s where it get’s interesting. About 63% of your atoms in your body are hydrogen. The rest of your body consists of “metals.” If you pick any 10 “metal” elements from your body, about 6 will be oxygen, 3 carbon, and 1 nitrogen. Since helium is a noble gas it doesn’t react much with other atoms chemically.
In other words, the ratio of elements in your body roughly corresponds to the ratio of useful chemical elements in the solar system.