Body odor (BO) is a complex chemical signature resulting from the interaction between skin bacteria and compounds secreted in sweat. The odor is a mixture of volatile organic compounds (VOCs) created when the body metabolizes food and responds to internal changes. These compounds are released through the skin, where resident microbes transform them, creating a unique and sometimes savory scent.
How Diet and Environment Influence Body Odor
Foods contain volatile compounds that the body cannot fully metabolize, leading to their release through breath and sweat. Spices like fenugreek, cumin, and garlic contain sulfur-rich compounds absorbed into the bloodstream after digestion. When expelled through sweat glands, these compounds interact with the skin’s microflora, creating a pungent, savory aroma that can mimic broth.
Heavy perspiration provides a moist, warm environment where skin bacteria thrive. Aerobic bacteria, particularly species of Corynebacterium, rapidly break down the proteins and lipids present in apocrine sweat. This bacterial action converts odorless precursors into odoriferous substances like 3-hydroxy-3-methylhexanoic acid, a volatile fatty acid with a distinct, savory scent.
Poor hygiene allows this bacterial population to proliferate and their byproducts to accumulate on the skin and clothing. If the environment is saturated with strong, savory smells, such as working in a kitchen, these external VOCs can cling to hair and clothes. The combination of environmental smells and sulfur compounds can create a persistent, soup-like impression.
Physiological Changes That Alter Scent
Internal physiological shifts can change the chemical composition of your sweat, resulting in a change in scent. When the body enters a state of ketosis, often due to a low-carbohydrate diet, it begins breaking down fat for fuel, producing ketone bodies. This pungent metabolic shift can combine with sweat to create a distinctly sharp or savory body odor.
Emotional stress triggers a different sweat response, as the release of hormones like cortisol activates the apocrine glands. This “stress sweat” is thicker and richer in fatty acids and proteins than temperature-regulating sweat. The increased availability of these nutrient-rich compounds provides a feast for skin bacteria, leading to a stronger, more noticeable odor that can be perceived as savory.
Specific medications may also alter the volume or composition of your sweat as a side effect. Certain antidepressants, nonsteroidal anti-inflammatory drugs (NSAIDs), and supplements can increase sweating, while others may cause the release of odorous chemical byproducts. This transient change in your body chemistry can temporarily overpower your normal scent profile, resulting in an unusual or uncharacteristic aroma.
When a Specific Odor Indicates a Health Condition
A persistent and unexplained change in body odor, especially one that cannot be linked to diet or hygiene, may signal an underlying health issue. The kidneys and liver are responsible for filtering toxins and waste products from the blood. Impaired function can lead to a buildup of compounds that are then expelled through the skin and breath. Kidney failure, for example, can cause uremia, where waste products accumulate and are released as a strong, ammonia-like odor known as uremic fetor.
Inborn errors of metabolism (IEMs) can prevent the body from properly processing specific amino acids or fatty acids. Certain disorders involving methionine metabolism can lead to the buildup of sulfur-containing compounds. These compounds produce an odor similar to boiling cabbage—a distinct, savory, and sulfurous scent.
If the savory odor is strong, persistent, and accompanied by other symptoms like fatigue or unexplained weight change, it warrants a medical evaluation. Consulting a physician allows for a proper diagnosis to rule out or identify any underlying conditions. Professionals can assess overall health and determine if the odor is a harmless dietary or hormonal effect or a symptom requiring further medical attention.