Image copyright Kathleen Prior

In Papua New Guinea, the popularity of the psychoactive betel nut is on the rise. With mouth cancer rates soaring, the nation is struggling to control its growing addiction.

Once reserved for sacred events, now almost half of Papua New Guineans chew betel nut.

It is common for children as young as six to chew it, and addicts admit using the drug every day from morning to night.

The chewing of betel nut, the seed of the Areca palm, is common across Asia and the Pacific.

In Papua New Guinea, where it is known locally as "buai", it is consumed with a mustard stick dipped in slaked lime powder.

Image copyright Kathleen Prior Image caption The sale of betel nut is a lucrative business

Chewed then spat out, it creates a sense of euphoria and alertness.

Customary practice

At an annual cultural festival in East New Britain province, the tell-tale signs of betel nut chewing are ubiquitous. Spittle and shells litter the ground, as men, women and older children laugh and chatter with lips stained bright red.

A clan from the Baining mountains are performing, and Philomena has travelled with them alongside her five children aged eight to 18 years. They are all chewing betel nut.

As Philomena chews her eyes widen and she begins to sweat. "It is a stimulant, it gives you a high feeling and keeps you going when you are becoming bored." Then a jet of red spit shoots from her mouth.

Gesturing with her hands, she speaks louder, "Now I am chewing it energises me. I have been psyched up."

Image copyright Kathleen Prior Image caption Many start chewing betel nut from when they are young kids

"If my children want to chew buai, they can. But they must make sure they eat first. If you don't eat and you chew, it makes you dizzy."

Her daughter Sophia, who is 18, has been chewing since she was 10 years old. As she speaks, she swirls the red mush around her mouth, giving her a lisp.

"Chewing buai makes me happy and gives me extra energy to complete my errands. Without the buai we would be tired and sleepy. It's part of our culture. Everyone in the family chews buai."

'Like a cup of tea'

Betel nut's active ingredient, arecoline, acts on the same receptor proteins in the brain as nicotine. It is highly addictive and also a carcinogen.

Papua New Guinea has the highest rate of oral cancers in the world. According to the World Health Organisation, nearly one in every 500 new cases of mouth and oropharynx cancer is in Papua New Guinea and it is the nation's biggest cancer killer.

Image copyright Kathleen Prior Image caption Betel nut consumption has seen a sharp rise

Dr Yvonne Sapuri, who diagnoses approximately two new cases of oral cancer weekly at the Kimbe General Hospital in West New Britain, fears these figures are hugely underestimated.

"Our statistics are not very accurate and a lot of cases go undiagnosed. I have noticed a big increase in the number of suspected cancer patients with mouth lesions."

This in a country with limited and healthcare facilities, frequent drug shortages and few oncologists. At Papua New Guinea's only specialist cancer centre, radiotherapy treatments were put on hold after its only radiation specialist resigned last year.

Image copyright Kathleen Prior Image caption Chewing the nut lends a sense of euphoria and alertness

"Most patients come to the hospital very late. Our health system is fragile and cancer services are not fully functional, so the survival rates are low."

With the popularity of betel nut on the rise, the future burden of cancer treatment on the national health system is a ticking time bomb.

"A lot more people are chewing betel nut now, more than in the past. Everyone knows it's bad for you, but people still do it because it is addictive. It becomes habitual, like having a cup of tea."

Old habits die hard

At a small roadside stall, Winifred sells betel nut, mustard and bananas that she grows behind her house. She chews betel nut, despite the health implications.

"It's bad for our health. We know but still we cannot leave it. It grows easily in the backyard! We just need to learn to chew responsibly."

Image copyright Kathleen Prior Image caption Herself selling betel nut, Winifred agrees people should be educated on the health dangers

"When my children were just six or seven they already knew how to chew," the mother-of-four continues. "I tried stopping them, they were too young. But they grew up with betel nut. We have to educate the children to not chew."

Long term exposure to the mixture dramatically increases risk.

"If a child started chewing betel nut at a very early age, he would be likely to get cancer before reaching the age of 30," said Dr Paki Molumi, surgeon at the ear, nose and throat department at Port Moresby General Hospital.

Support for a ban

In an urgent crackdown, a ban on the sale and consumption of betel nut across Port Moresby has been in force for three-and-a-half years. It had been estimated that £500,000 worth was traded in the capital each week.

The move was declared "political suicide" for the city's Governor, Powes Parkop, who spearheaded its implementation. In the weeks leading up to the country's general election, the ban was partially lifted.

Image copyright Kathleen Prior Image caption Known as "buai", betel nut is consumed with a mustard stick dipped in slaked lime powder

After a long electoral process, the nation looks ahead to a second term under incumbent Prime Minister Peter O'Neill. At the end of July it was announced that Parkop had also retained his seat.

Now, the ban allows regulated sale at approved locations. But it was marked by controversy: it was criticised for police brutality in enforcement and for ruining the livelihoods of betel nut suppliers. One MP even filed a court petition questioning its constitutionality.

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A stain on the city

It is true that many Papua New Guineans rely on the sale of betel nut for their livelihoods. A native cash crop, betel nut is referred to as "green gold", and it is completely untaxed.

Markets often have an area dedicated solely to betel nut vendors. Prices for one betel nut and mustard stick vary between 6 cents to $1.30 (5p to £1), dependent upon the location, season and recent growing conditions.

For Nuari, betel nut sales are her main source of income. She tends to the plants herself, and when they bear fruit she comes to the market to make some cash. If there are good sales, she will make £25 in a day. "With the money I make I can sustain myself and can buy things like soap and salt, the small things I need in life."

Image copyright Kathleen Prior Image caption Nauri agrees that there should be a ban

Even heavy users like Nauri support the ban. "The government has to stop people chewing because it makes so much rubbish. Everyone spits everywhere and it makes the place dirty - it's unhygienic."

One of the motivating factors behind the ban was to clean up the capital from this residue. The spitting of pathogenic saliva increases the spread of disease. In a country with one of the highest infection rates of tuberculosis in the world, this habit poses huge contamination risks.

Future of a dependent nation

Last year the inaugural No Betel Nut Day was held to educate citizens on the risks and early symptoms. This year it was postponed because of a date clash with elections - the minister of health lost his seat.

For doctors delivering devastating terminal diagnoses, it's too little, too late.

"We lack the public awareness aspect of preventive health...Betel nut is now a part of everyone's life, and it's disturbing to see parents give it to their young children," Dr Sapuri says.

"It's become a norm and so it is very difficult to fight it."

All pictures copyright.