Lower abdominal pain or pressure can be indicative of a bladder infection.

Few of us give our belly buttons a second thought - but perhaps we should. Here are some navel facts you might want to think about...


Don’t wash yours with antibacterial soap

Our navel is inhabited by hundreds of friendly bacteria species, according to a North Carolina State University study. Researchers from the Belly Button Biodiversity project took swabs from 60 navels, which revealed more than 1,400 species of bacteria, including one responsible for smelly feet and others thought to protect skin.

‘The belly button is kind of a nature reserve on your body,’ says Rob Dunn, an associate professor from the university.

Researchers also found the micro-organism make-up in each person’s belly button is unique. Your own bacteria are your first line of defence, because they compete with and attack viruses and germs that land on the skin. For this reason Professor Dunn does not recommend anti-bacterial wash.

‘I use soap and water and try to never touch anti-microbial products.’


So that’s why you have got an ‘innie’

Around 90 per cent of us have an ‘innie’ - when the belly button goes inwards. When a baby’s umbilical cord is clamped - typically 3cm from the navel - it leaves a small stump behind which usually drops off within two weeks. Whether it’s an ‘innie’ or ‘outie’ may be linked to how the cord is detached. If it’s clamped and cut, it’s more likely to be an innie, but if it’s been tied and cut, it may be an outie.

Women’s belly buttons can change appearance during pregnancy. ‘The pressure of the baby can push out the soft tissue, leaving the belly button completely flat or turning it into an outie,’ says Nikki Khan, a midwife at BMI Syon Clinic in Brentford, Middlesex. It generally returns to normal, but sometimes stretches permanently.


Why surgeons love belly buttons

The umbilical cord connects the growing foetus to the placenta, providing it with oxygen and nutrients needed for development. But after birth our belly buttons didn’t serve much purpose - until recently.

Now the belly button is coming into its own in so-called ‘orifice’ surgery. Keyhole surgery involves inserting tiny cameras and tools into the body via two or three small incisions known as ‘ports’.

For abdominal or pelvic surgery this can now be done through just one incision in the belly button, which means less chance of wound infection and no scar. Hernia repair, removal of the gallbladder or the appendix, some bowel cancer surgery, gastric banding and hysterectomies can all be performed like this.

And as surgical equipment becomes more advanced, more operations are likely to be conducted this way, says Professor John Erian, consultant gynaecologist at BMI Chelsfield Park Hospital, Kent.


How yours could go wrong...

Belly buttons can become infected, which often affects obese people with large skin folds covering it up.

‘This area is likely to get hot and moist, an environment which can lead to fungal infections,’ says Dr Adam Friedmann, a consultant dermatologist at the Harley Street Dermatology Clinic, London.

People with psoriasis - a skin condition causing red, flaky, crusty patches of skin covered with silvery scales - often have it in their belly button. Harmless warts can also appear on the skin as we age. This includes the belly button, where they can become painful, bleed, and may need to be surgically removed. In rare cases a firm, red, painless lump can appear. This is known as the Sister Mary Joseph nodule and is a marker for internal cancers in the pelvis or abdomen. ‘Usually by the time it manifests, the cancer is quite advanced,’ says Dr Friedmann.


PS. . . why belly button fluff is usually blue

Belly button ‘fluff’ is more common in hairy, overweight, older men with ‘innie’ belly buttons, says Dr Karl Kruszelnicki, an Australian doctor and radio presenter who surveyed nearly 5,000 people about their navels.

After examining respondents’ belly button fluff, he found it largely consisted of clothing fibres, sweat and skin cells. It gets moved into the belly button by the hair on the belly - so the hairier the stomach, the more fluff there is. People with bigger bellies build up more lint because they have deeper navels.

And why is it often blue? Dr Kruszelnicki says: ‘Because a lot of clothes are blue.’ - Daily Mail