Why Do Feet Smell? They’re Fermenting!

Why Do Feet Smell?

Feet smell due to the overgrowth of bacteria. Sweaty feet are the source of foot odor.  Each foot has over 250,000 sweat glands that produce up to a pint of sweat daily.  However, it’s not the sweat itself that smells.  It is the natural bacteria present on your body feeding on that sweat that produce an odor.

Hands Have Sweat Glands, Why Don’t They Smell?

The hands have nearly as many sweat glands as the feet, so why don’t the hands smell?  Sweat does not accumulate on the hands, inviting an overgrowth of bacteria. It simply dissipates.  The conditions that a sock and a shoe create cause the problem.  Bacteria multiply when conditions are dark, warm, and moist- the conditions created by a sweaty foot inside a pair of shoes and socks.  Some bacteria are good; an overgrowth can cause problems.

Your Feet Are Fermenting

Feet smell because they are fermenting. Fermentation is the process by which an organism breaks down a substance and then produces a byproduct.  In smelly feet, bacterial colonies feed on the waste material in sweat and produce a byproduct of organic acid, which produces an odor.  In the case of foot odor, one of the culprits could be Micrococcus, commonly found on mammalian skin and soil.

How Do I Get Rid of the Body’s Bacteria?

Good hygiene is important for overall health, but even the most vigilant hygienic practices will not remove all bacteria from your body.  The human body is a virtual microbiome of bacteria. In fact, researchers have identified more than 10,000 microbial species that coexist within the human body.   Though, as a society, many think of bacteria as an organism that will make us sick, many bacteria are beneficial and even necessary to human life.  For example, the bacteria in the gastrointestinal tract are responsible for processing the food we eat.  Without it, we would be unable to digest food and absorb its nutrients fully.

If All Humans Carry Bacteria, Why Do Some Feet Smell More Than Others?

All things being equal, such as good hygienic practices. . .

Sweating is the body’s cooling process when it becomes heated in response to external heat, exertion, or even nerve stimulation.  Individuals have natural variations in how their bodies sweat.   Some people naturally sweat more than others do.  This fact, coupled with the fact that some people are more physically active and more highly reactive to stressful situations, means that some will naturally sweat more than others. Excessive sweating, or hyperhidrosis, could be a sign of an underlying medical condition.

Additionally, every individual has bacterial communities unique to him or her.  A group of researchers from CU Boulder and the Washington University School of Medicine demonstrated this fact and the fact that these personalized bacterial communities vary widely from one area of the body to another.

So Smelly Feet Are a Lost Cause?

Just because you sweat more doesn’t mean that you have to surrender to smelly feet.  You simply need to work harder at preventing the problem.  Your key point of focus is to inhibit bacteria’s growth by keeping your feet, socks, and shoes dry.  This means never wearing shoes without absorbent socks and never wearing wet shoes.  Use a foot deodorizer just as you would an antiperspirant.  It will help to control the odor and the smell.  To make your shoes last longer, purchase odor-absorbent insoles that you can replace as often as needed.

Resources

• Clausen, University of Arkansas Research Frontier – Why Do Feet Stink?
  
• University of Wisconsin-Microbiology Laboratories – An Introduction to Lactic Acid Bacteria
  
• WebMD – Is Your Excessive Sweating Caused by a Medical Problem?
  
• University of Colorado Boulder – Normal bacterial makeup of the body has huge implications for health, says CU-Boulder professor

Print

• Marshall. “A comparative study of the cutaneous microflora of normal feet with low and high levels of odour.” Journal of Applied Bacteriology. 1988; Volume: 65; No: 1; Pages 61-68