HIGHLANDERS have used it through the ages to help them perform great feats of strength while staving off hunger and thirst. Roman soldiers also took it to give them the endurance to fight prolonged battles against the barbarian hordes.
Now heath pea, a long-forgotten wild Scottish plant, is to be reinvented for the 21st-century as a potential aid for dieters.
Richard Swift, a London-based businessman, is planning to fund a trial of the heath pea's properties to find out whether it could sustain a new cottage industry in rural Scotland. He has just won permission from Scottish Natural Heritage to collect wild plants and is organising a group of testers.
According to botanical records, heath pea - Latin name lathyrus linofolius - was a vital ingredient of the Highland diet when food was scarce until the 18th-century. The prized part was the pea-sized tubers that were stripped off the roots and dried. Once ingested, they provided a big boost to Highlanders in battle or in the fields, as well as preventing thirst and hunger pangs. It is the latter quality that is of interest to dietary scientists.
Swift, a project manager who formerly worked for the University of Westminster, is currently asking landowners to help organise the collection of the tubers.
"I am interested in it for two purposes; hunger relief and for maintaining energy.
"These days as soon as people get hunger pangs they have to do something about so it could be potentially a diet aid.
"The 17th-century literature also tells us that it allowed people to work and dig the fields all day. So it could be good for athletes or boxers in training, who want to maintain a certain weight. It could be part of their survival kit."
Once the tubers had been collected he would proceed to testing among volunteers.
"We have to find out if it is safe and effective. If it is both then we will have to raise funding so work can be carried on."
Heath pea could become a major sustainable crop in the Highlands, Swift added. "It grows at the moment on what could be termed marginal ground but there is no reason it couldn't grow on good agricultural land. But I want to keep it in the Highlands so it benefits local economies. It would be marketed as an ancient food without any claims as to its benefits."
Swift has held initial talks with Highland Natural Products, a Dingwall-based company developing a number of wild plants for the pharmaceuticals market.
Managing director Richard Constanduros said heath pea had great potential but no one had as yet developed it.
"It's got a pleasant liquorice taste to it," he said. "The problem is that it is difficult to harvest. It occurs in grass swards and you have to dig down for it. It's a nightmare."
Constanduros believes that heath pea is among a number of Scottish medicinal plants whose properties have been lost over time.
"My theory is that Britain was the first country to industrialise and there was a huge migration to towns such as Glasgow," he said. "In the process we lost that connection with the land and plants. It is not the same in countries like Germany. There, even workers in car plants go back to their farms in the evenings and they still have that connection."
Some academics believe heath pea has similar properties to the coca leaves chewed by Peruvian tribesmen.
Dr Brian Moffat, an archaeological botanist, who has found remnants of heath pea at a 12th-century monastic hospital site in East Lothian, believes the plant conveys "superhuman" properties.
In a research paper he says accounts from the 17th-century suggested Highlanders would eat a heath pea tuber any time a feat of strength or endurance was required. It might also explain why caber tossing became a peculiarly Highland sport.
Moffat, who says research into the plant's chemistry is required, describes the taste as "incredibly sweet" with an anise-like aroma. This would suggest it contains transethanol, a substance 300 times sweeter than sugar, accounting for its energising properties.
Heath pea could now follow in the footsteps of bog myrtle, another Scottish plant being developed by research chemists at high street chain Boots for its anti-ageing properties.
As well as Scotland, lathyrus linofolius grows in other upland areas of Europe. It is believed to be a plant whose roots were eaten by Julius Caesar's soldiers in preparation for the battle of Dyrrhacium in 48 BC.