Why do my feet smell?

Foot odour affects more people than it may seem. This is because our feet sweat more than other parts of the body, as they contain approximately 250,000 sweat glands. Quickly becoming damp, they turn into breeding grounds for bacteria, including the Kytococcus sedentarius, which feeds on the salt present in our sweat.

When it comes to unpleasant odours, these microorganisms and sweat are not a good combination. Indeed, it is these, not perspiration, that are the cause of smelly feet. These bacteria and various fungi accumulate between the toes and multiply by feeding on the dead cells and sebum present on and under the feet. It is when they decompose that they release an unpleasant smell. Indeed, this is the case with the bacteria Brevibacterium spp which feeds on the keratin of the scales on the feet, breaking down methionine, an amino acid, to form methane-thiol, the source of the bad smell.

Do you wear closed shoes or trainers all day long? You could have athlete's foot, one of the other causes of excessive foot perspiration and therefore, the development of these harmful bacteria. Wearing closed shoes and socks that do not allow good air circulation can trap moisture and promote bacterial proliferation. Closed shoes also create a dark and warm environment, ideal for bacterial growth.

Beyond abnormally sweaty feet, particularly between the toes, other symptoms of athlete's foot include intense itching and/or skin rashes that can lead to infections. The combination of sweat, bacteria, and infections inevitably results in unpleasant odours.

During changes or disruptions in women's hormonal cycles, the body undergoes numerous modifications. These alterations affect perspiration, leading to an increase in bacterial growth and a change in body odour, which can be one of the causes of malodorous feet. In addition to pregnancy, menstruation or menopause, which influence female perspiration, it's also worth mentioning puberty, which affects that of adolescents.

Indeed, a study has shown that changes in oestrogen levels influence the signalling pathways of norepinephrine (NE) and serotonin (5-HT), which are crucial for the processing of thermoregulation, in the preoptic area of the hypothalamus. A hormonal shift then modulated key neurotransmitters and the expression or function of their receptors, thereby altering the response patterns of thermoregulatory circuits and changing sweating thresholds.

The effects that stress can have on the mind, as well as the body, can often exceed our understanding. In this regard, stress, along with depression, anxiety or overwork, are thought to be capable of activating a dual innervation pathway that could lead to an increase in perspiration. And with abnormal perspiration comes a favourable environment for the growth of certain bacteria. Uncontrollable foot odour is then an inevitable consequence.

Shoes and removable insoles are often made from synthetic materials. These non-breathable materials absorb foot odours along with sweat and other impurities. Therefore, if you do not regularly wash your shoes and allow them to dry in sunlight to kill bacteria, they can end up smelling as bad as your feet. Moreover, this unpleasant odour can be transferred to clean feet.

It is not enough to simply take a bath and rinse your feet. It is crucial to wash them thoroughly and regularly with soap, scrubbing between the toes and brushing the nails. Indeed, this is where fungal infections develop and persist. And it is also this that causes the unpleasant odour of feet.

After drying your feet, you can apply our 10-ingredient body moisturising cream for deeply hydrated skin. It is suitable for all skin types, even sensitive skin.

Note: There are solutions to counteract the effect of unpleasant foot odours.

DEECHER D. C. & al. Understanding the pathophysiology of vasomotor symptoms (hot flushes and night sweats) that occur in perimenopause, menopause, and postmenopause life stages. Archives of Women's Mental Health (2007).

HARKER M. Psychological Sweating: A Systematic Review Focused on Aetiology and Cutaneous Response. Skin Pharmacology and Physiology (2013).