The soles of the feet are said to be the part of the body that sweats the most, but sweat itself does not have an odor. Foot odor is caused by the proliferation of bacteria due to sweat, sebum, and keratin.

First, we will explain in detail the causes and conditions under which the bacteria that cause odor grow.

The odor is caused by the proliferation of bacteria

Foot odor is caused by the proliferation of bacteria that normally live on the skin. The causes of bacterial proliferation are as follows:

• Steam caused by sweat
• Excessive sebum secretion
• Dead skin buildup

Normally, the resident bacteria present on the skin of many places, including the feet, plays a role in forming a barricade to prevent bacteria from entering from the outside. However, when the inside of shoes or socks becomes steamy due to moisture from sweat, the resident bacteria feed on sebum and keratin, and grow, producing substances such as acetic acid and isovaleric acid that emit a foul odor.

Conditions conducive to the proliferation of germs

The germs that are inseparable from foot odor are said to proliferate easily under the following conditions:

• High-temperature and humidity
• Poor ventilation environment
• Mold infections and skin diseases

Bacteria grow best in environments with temperatures above 25°C and humidity levels above 70%. Therefore, the hot and humid months of June to September are the perfect season for bacteria.
Shoes and socks that do not have good ventilation also create a hot and humid environment that bacteria thrive in.
In addition, cases where the feet are infected with a fungus called tinea fungus, which causes athlete's foot, or where the feet sweat excessively regardless of the season (plantar hyperhidrosis), are also areas where germs are likely to grow.

Here are some characteristics of people with smelly feet.

• Sweating frequently on the soles of the feet
• Shoes and socks have poor ventilation
• Not cleaning your feet

In the next chapter, we will explain in detail the mechanism behind foot odor. If this applies to you, please read on.

Sweating frequently on the soles of the feet

If you sweat a lot on the soles of your feet, you need to be careful about foot odor.

There are many sweat glands on the soles of the feet that produce sweat to regulate body temperature, but the cause of the odor is not the sweat itself, but the growth of bacteria due to high temperatures and humidity.
In particular, since it is difficult to wipe off sweat from your feet immediately, if they remain sweaty for a long period of time, it becomes an environment that is conducive to the growth of germs.

Use an antiperspirant or deodorant before you sweat to reduce sweating on the soles of your feet.

Shoes and socks have poor ventilation

If you wear shoes or socks that do not have good ventilation, sweat from your feet cannot evaporate and dry, which increases the humidity around your feet and often leads to smelly feet.
When wearing leather pumps, sandals, or boots that don't breathe, use insoles that absorb moisture and dry quickly.

We recommend socks made from natural fibers such as cotton, linen, silk, and wool, rather than synthetic materials such as nylon and polyester. If you are in the habit of wearing stockings, choose those that have been treated with antibacterial and antimicrobial properties.

It is also important to choose shoes and socks that fit properly. If they are too small, they will have poorer breathability, and if they are too big, friction will occur inside, making humidity more likely to increase.

Not cleaning your feet

To prevent foot odor, it is important to keep your feet clean. However, even if you think you have washed your feet thoroughly when bathing, dirt may remain between your toes and in the gaps between your nails. Be sure to wash carefully, even in small areas, to thoroughly remove the day's dirt.
If you don't take a bath because you're tired or don't take a shower at night, you are at high risk of having smelly feet, so we recommend that you take a foot bath after returning home. Even when you're out and about, it's a good idea to use a foot wipe if you sweat a lot.

In addition, wearing dirty socks will lead to poor foot hygiene. In addition to changing your socks every day, when washing your socks, turn them inside out to wash off sweat, sebum, and dead skin cells that have built up on the inside.

If you are troubled by foot odor, try the recommended odor control measures explained in the next chapter. We will introduce some easy and practical measures that you can put into practice immediately.

Remove dirt and dead skin from your feet

To remove dirt and dead skin from your feet, wash them thoroughly using antibacterial soap or other products.

Before washing, soak in a bathtub or take a foot bath to loosen dirt and dead skin cells so they can easily peel off, then lather up with soap or wash thoroughly.
We also recommend a foot brush designed specifically for washing your feet. It not only helps to eliminate odors, but also has a massaging effect, helping you to feel refreshed after a long day.
After washing, rinse thoroughly with warm water and wipe off the water with a clean towel. If moisture remains on your feet, it can lead to the growth of bacteria, so it is important to dry them thoroughly.

Cut your nails regularly

Toenails are prone to accumulating dead skin, so be sure to cut them regularly.

The best time to cut your nails is after a bath or shower when your nails are clean and soft.
If your nails are too short, it can lead to problems such as ingrown nails and ingrown nails, so it is best to cut them to the same height as your finger. Be mindful of cutting your nails square, and if you are concerned about the corners, use a nail file to file them down and shape them.

Nails dry out easily, so after cutting them, moisturize them with lotion or cream to maintain their barrier function and reduce excess sebum production.

Dry your shoes

It is said that we sweat about a cup's worth (about 1 ml) from the soles of our feet per day, and a large amount of sweat soaks into shoes that are worn all day.
If you put your shoes back on before the sweat has dried, the humidity in the shoes will increase and cause a bad odor, so be careful not to wear the same shoes for more than two days.

It is important to put desiccants, dehumidifiers, newspapers, kitchen paper, etc. inside the shoes and dry them thoroughly in a well-ventilated place. If you want to dry them quickly, use a shoe dryer or hair dryer.

Also, be sure to wash your shoes regularly if they can be washed, and change the insoles of shoes that cannot be washed.

Foot odor can be prevented not only through foot care, but also from the inside out, both physically and mentally.
Here are some lifestyle changes that are effective in combating foot odor.

review your eating habits

In order to improve the quality of blood, which is the raw material for sweat, it is important to review your diet.
The foods listed below have antibacterial properties that suppress the activity of active oxygen and are expected to have the effect of thinning the blood.

Ministry of Education, Culture, Sports, Science and Technology | "Standard Tables of Food Composition in Japan (2023th Edition) Supplementary Edition XNUMX"Tabulated from

On the other hand, foods that are high in animal protein and fats promote excess sebum secretion, increase bad bacteria in the intestines, and create an environment that is prone to the development of bad odors.

When trying to combat foot odor through your diet, eat plenty of vegetables, fruits, and ingredients that have antibacterial properties, and avoid foods that contain animal protein and fats.

relieve stress

Stress is closely related to the amount of sweating.

When you feel stressed, your autonomic nervous system becomes disrupted and the sympathetic nervous system becomes dominant, causing excessive sweating from the sweat glands in your feet, which are already prone to sweating, creating an environment that is favorable for the proliferation of germs. When you are stressed due to physical or mental fatigue, find ways to relieve stress, such as getting enough rest, exercising, or taking up a hobby.

The normal bacteria present on the feet multiply in the hot and humid environment caused by sweat, feeding on sebum, dirt, and dead skin cells, causing odor.
Therefore, people who sweat a lot on the soles of their feet, wear shoes or socks that are not breathable, or do not have the habit of keeping their feet clean tend to have smelly feet. If you are concerned about foot odor, try to remove dirt and dead skin from your feet and cut your nails frequently. It is also important to thoroughly dry your shoes after wearing them for a day.

In addition, you can take measures against foot odor from both an internal and mental perspective by reviewing your diet and reducing stress.