Causes of Smelly Feet
Bacteria are everywhere - in the air we breathe and every surface we come into contact with. They are all over your body too. Usually this is nothing to be worried about - many are benign and their presence stops other harmful bacteria from gaining a foothold.
Bacteria flourish in warm, moist places, and feet with more than 250,000 sweat glands are a perfect home. As our feet get hot, they perspire. The sweat evaporates and cools them down, but if you are wearing shoes and socks, the liquid has nowhere to go, creating a perfect environment for microbes.
Sweaty Smelly Feet
Sweat is trapped and the bacteria reproduce like crazy. The actual odor is a by-product of the bacterial metabolic processes. They ingest various salts and minerals, and excrete waste products. The main waste product that causes foot odor is isovaleric acid, which is a fatty acid. And as well know it has a penetrating smell.
The two main types of bacteria that cause smelly feet are Corynebacteria and Micrococcus:
Corynebacteria - these are Gram-positive rod-shaped bacteria that are widely found in nature. Most strains are benign but some are human pathogens such as Corynebacterium diphtheriae.
Micrococcus - these are Gram-positive and spherical-shaped. Generally benign they can be found in many places other than the human body such as in the soil, in animal and dairy products, and in water.