The unpleasant phenomenon of cheesy-smelling feet is medically known as bromodosis. It is an extremely common occurrence caused by a mixture of foot sweat and the bacteria present on the skin. The odor is not caused by sweat itself, but by volatile organic compounds released when bacteria break down sweat and dead skin cells. Understanding this interaction explains why the smell happens and how to manage it.
The Science of Foot Odor Production
The human foot contains one of the highest concentrations of sweat glands, approximately 250,000 eccrine glands per foot. These glands produce odorless sweat composed primarily of water and salt. When this sweat is trapped inside a shoe and sock, it creates a warm, moist environment perfect for the skin’s resident bacteria to multiply rapidly.
Bacterial Metabolism and Odor
The bacteria feed on the sweat and constantly shed dead skin cells. As they consume this material, they release waste products called volatile organic compounds (VOCs). These chemical byproducts produce the noticeable smell. The specific combination of bacteria determines the odor quality, which can be vinegary, sulfurous, or, most commonly, like cheese.
The Specific Link to Cheese Smell
The link between feet and cheese involves specific bacterial species. The primary compound responsible for the cheesy aroma is isovaleric acid. This acid is generated when bacteria, such as Staphylococcus epidermidis, break down the amino acid leucine in foot sweat. Isovaleric acid is a short-chain fatty acid known for its pungent, cheese-like smell.
Brevibacterium and Cheese
Another bacterial group, Brevibacterium, also contributes significantly to this specific odor. This genus is deliberately used in the ripening of strong-smelling cheeses, including Limburger and Munster. When Brevibacterium consumes dead skin, it releases sulfur-containing compounds like methanethiol. This process adds a distinct sulfurous, cheesy note to the overall odor profile, explaining the similarity between the smells.
Practical Steps to Eliminate Foot Odor
Managing foot odor focuses on reducing moisture and controlling the bacterial population. A simple strategy is to wash your feet daily using antibacterial soap, then drying them completely, paying attention to the spaces between the toes. Removing dead skin with a pumice stone helps eliminate food sources for the bacteria. For added dryness, medicated foot powder or talcum powder can be applied before putting on socks.
Footwear Management
Footwear management is important, as shoes can harbor bacteria and moisture. To manage footwear effectively:
- Do not wear the same pair of shoes two days in a row, allowing 24 hours for them to dry out completely.
- Choose shoes made of breathable, natural materials, such as leather or canvas, over synthetic ones to promote air circulation.
- Consistently wear moisture-wicking socks made from wool or synthetic blends, as cotton tends to absorb and hold sweat.
Advanced Control Measures
If home care efforts do not resolve the issue, over-the-counter products can provide stronger control. Applying an antiperspirant directly to the soles of the feet helps reduce sweat production. Weekly foot soaks in warm water mixed with Epsom salts or vinegar can reduce bacterial populations and dry the skin. If the odor persists after several weeks of diligent home treatment, consulting a podiatrist might be necessary to rule out a fungal infection or address excessive sweating (hyperhidrosis).