In a lodge in Manang, a woman adjusts her headscarf as she laughs at the sight of her grandson feeding from his mother's breast. The curious one-year-old can't resist a quick break from his feed to see what's going on around him in the room.

Only then do I notice his grandmother has a swelling around her neck, a goitre. I am surprised-not to see it, but to realise this is the first I've seen in five days of trekking. Things have changed dramatically from when I was here 25 years ago.

Further along the trail, a crippled and dumb middle-aged man shows me a hand-written note which reads: 'My name is Raj Singh, I am physically handicapped, please help me.' I can see at once he is suffering from cretinism. He is physically and mentally impaired due to his mother's iodine deficiency at the time of his birth. He has been given this note to help him solicit donations from tourists. That is also new.

In this district in 1982, there is a strong chance that a young mother, like the one at the lodge, would have had a goitre, and her child would have been born with cretinism. Back then, while making a film about iodine deficiency for UNICEF, I took hundreds of photographs of people of all ages with goitres, some the size of footballs or large grapefruit. They were not hard to find. In one village, 80 percent of the population had goitres and 20 percent of all newborn children suffered from cretinism.

Today the term 'cretin' is considered pass?, yet back in the early 1980s the medical profession had to redefine the word because of the high incidence of the illness throughout the Himalayas. At that time I followed a medical team through Manang, under the leadership of Dr Purushotam Thapa, which gave iodine oil injections to young women to provide five years of protection. The situation has now improved dramatically. Iodine Deficiency Disorders (IDD) no longer appear near the top of Nepal's list of major health problems.

Historically, iodine deficiency has been a problem in most of the world's major mountainous areas, where people lived far from the sea and so did not have access to naturally occurring iodine or sea salt in their diet. In the Alps, the Rockies and the Andes, it was common at the beginning of the 20th century to find people with goitres. In the Himalayas, the scale of the problem was not fully understood until the 1980s. Many remote communities had been devastated.

Children born to mothers with iodine deficiency suffered problems ranging from mild mental and physical stunting to more severe mental deficiency, deaf mutism, dwarfism and hypothyroidism.

Just 150 micrograms of iodine per day in an adult's diet is enough to prevent these conditions, but 25 years ago few in Nepal knew this. Many blamed the water supply and responded with offerings to the gods. Children with severe cases were often tethered at home to avoid embarrassing the family.

Nepal in the 1980s lacked the infrastructure to cope with the problem. There were only 300 registered doctors, most of them in the Kathmandu valley and main towns, and there was little scope for any mass media campaign as few hill areas had radio access and fewer than 20 percent of women could read.

Initially, UNICEF worked with the government to introduce iodised salt packed into gunny sacks for distribution in the hills, but by the time the salt reached the remote mountain communities, the iodine had leached out, making it no better than local rock salt. They then launched an emergency protection program targeting three million young mothers to receive iodine oil injections.

I travelled with one of these teams and watched villagers bring out their family members-both adults and children-believing the injection would cure them. The scale of the problem was shocking. The injection could not cure those affected, and all too often we saw severely mentally impaired adults, who had spent their entire lives hidden away indoors, returned to their dark rooms by disappointed relatives.

In the late 1980s, a concerted effort was made to step up the campaign against IDD throughout what was then known as the 'Himalayan goitre belt', stretching from Pakistan to Burma. The 43rd World Health Assembly in 1990 resolved to completely eliminate these disorders. So far, only Bhutan has declared the complete eradication of IDD, but Nepal is on track to follow. The key lies in being able to supply iodised salt to more than 90 percent of the population. For remote areas like Manang, the humble plastic bag plays a vital role, keeping the salt fresh and preventing the iodine from leaching out before it reaches its destination.

Although the fight against IDD may be nearly won, there are still scores of people living in the hills who need assistance as a result of this deficiency.

George McBean worked with UNICEF in Nepal in the 1980s and made the film, The Golden Throat.

All bagged up

The main reason for the dramatic decrease in goitre and cretinism in Nepal has been an aggressive government policy to provide iodised salt to the remotest regions of the country.

The big challenge here is access. Because it takes sometimes a week or more to walk to these far-flung valleys the volatile iodine in the salt evaporates. The distribution system must also be efficient so the salt isn't stored for long periods after iodisation.

A successful 30-year combined effort by government, the private sector and aid agencies has all but wiped out visible goitre in Nepal.

The percentage of Nepali households with access to iodised salt is now 90 percent-much higher than India (50 percent) or Pakistan (17 percent). In fact, Nepal is the only country in South and Southeast Asia that has such high use of iodised salt.

Part of the reason for the success has been the fact that the government has made Salt Trading Corporation the sole dealer in this important commodity. This has ensured a uniform nationwide supply of subsidised iodised salt, ensuring quality and low prices. The subsidy has been supported by the Ministry of Health, the Indian government and UNICEF. Iodisation and packaging plants are located strategically in Birtamod, Biratnagar, Janakpur, Bhairawa, Narayanghat and Nepalganj.

But with STC going through a management transition, the salt distribution network could be affected. Non-edible salt for industrial use is also being smuggled into Nepal from India. This has below-threshold levels of sodium chloride and is unfit for human consumption, raising the danger of goitre resurfacing.
The salt consumed in northern Nepal ("bhote noon") is derived from Tibet's lakes but lacks iodine. STC had plans to set up iodisation plants for Tibetan salt at the Chinese border in Hilsa in Humla district, and in Dolpo.

The government spends more than Rs 150 million subsidising the annual consumption of 150,000 tons of salt every year, making it among the cheapest in South Asia. Salt in Nepal costs Rs 10 per kg compared with Rs 16 in India, Rs 17 in Pakistan, Rs 20 in Bangladesh, and Rs 23 in Sri Lanka.

Ninety percent of Nepali women are also anaemic because they don't get enough iron in their diet. With donor support, the government is now looking at double-fortification of salt with iron and iodine to address this problem in the diet of Nepali mothers.