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Sour body odor is not always a cause for concern, but it should be monitored closely, especially if it occurs suddenly and intensely.
Sour body odor: Possible causes
Our sweat is initially odorless. It is only through the interaction of bacteria on our skin, which break down the proteins and fatty acids in sweat, that the typical body odor develops. However, a sour smell can indicate various causes that go beyond the normal sweating process.
- Nutrition and digestion: Our diet has a significant influence on our body odor. Strongly spiced or high-fat foods such as garlic, onions, curry, or spicy dishes can cause it to become sour. Alcohol—especially wine and beer—as well as certain food intolerances (e.g., lactose intolerance or fructose malabsorption) can also affect the metabolism and cause a noticeable sour smell.
- Hormonal changes: Changes in hormone levels, such as those caused by puberty, pregnancy, or menopause, often affect the smell of our sweat. Hormonal fluctuations can increase the activity of your sweat glands and alter the bacterial flora on your skin, resulting in a more intense and unusual odor.
- Stress and emotions: Stress activates the apocrine sweat glands, which produce particularly large amounts of sweat in the armpits, palms, and soles of the feet. This type of sweat contains more proteins and lipids, making it the perfect “food source” for bacteria. If you are under constant stress, your sweat may take on a more sour and unpleasant odor.
- Infections and diseases: Sometimes, a sour body odor can be a sign of infection. Fungal infections on your skin or in your digestive system, such as candida yeast, can cause an unpleasant sour smell. Certain metabolic disorders such as diabetes or liver and kidney dysfunction also alter the chemical processes in your body, which can result in an unusual body odor.
When sour body odor becomes a warning sign
A slight change in body odor after eating spicy food or when nervous is usually harmless. However, if the odor suddenly changes significantly, persists for a long time, or is accompanied by symptoms such as nausea, fatigue, skin changes, or weight loss, you should consult a doctor.
- Diabetes and ketoacidosis: Poorly controlled diabetes mellitus can lead to diabetic ketoacidosis, which is a medical emergency. In this case, the body breaks down more fat and produces ketone bodies. These lead to a sweetish-fruity, sometimes sour smell, often reminiscent of nail polish remover (acetone). In combination with symptoms such as severe thirst, nausea, vomiting, abdominal pain, or confusion, immediate medical attention is required.
- Liver and kidney disease: The liver and kidneys are central detoxification organs. If they malfunction, metabolic products can accumulate in the blood and be released through the skin. This can result in a sour body odor.
- However, more typical of advanced liver disease is foetor hepaticus—a sweetish, putrid odor that indicates an accumulation of ammonia and other toxins. Accompanying symptoms such as jaundice, fatigue, or swelling should always be checked by a doctor.
- Metabolic disorders: Rare genetic disorders such as trimethylaminuria (also known as “fish odor syndrome”) can cause a very unpleasant body odor. In this disorder, the substance trimethylamine, which is normally broken down in the liver, is excreted unchanged.
- The smell is more fishy than sour and intensifies after eating foods rich in choline, such as eggs, legumes, or fish. Those affected should consult a specialist metabolic clinic.
- Weak immune system and infections: A weakened immune system means that the body cannot effectively fight off infections. Infections of the skin or digestive tract can also be accompanied by a strong sour body odor. Fungal or bacterial infections in particular can alter the smell of sweat and cause an unpleasant odor due to inflammation or pus formation.
Practical tip: Keep a food diary
If you have an unclear or recurring sour body odor, keeping a food diary can be helpful.
- This allows you to identify connections with certain foods—especially sulfur-containing vegetables (e.g. broccoli, cabbage, garlic), alcohol, or processed foods.
- Individual intolerances can also be identified more quickly in this way.
