Eulalee Thompson - BE WELL

In one dash or two, the affable and lanky world and Olympic record-holding sprinter, Usain Bolt, internationalised the Nuh Linga, Gully Creeper and the good ol' Jamaican yellow yam.

Yes, the yellow yam. This is the 'performance-enhancing substance' which the international press has been crediting with Bolt's mind-boggling sprinting prowess.

They might have received help from some of Bolt's relatives. TIME magazine, for instance, spoke to his Aunt Lilly 'from the patio of her restaurant', Miss Lilly's Bar and Shop in Trelawny, and said that she admitted that the secret to the sprinter's success is the 'mouth-watering yellow yams' that she still cooks for him at her restaurant.

Well, you know me. I wanted to get to the root of this emerging yam-powered-athletic-performance debate. So, off I went to pay a visit to the University of the West Indies' Biotechnology Centre to have a chat with members of the Yam Research Group.

"It can influence athletic performance," was research fellow, Dr Perceval Bahado-Singh's emphatic response. "But only if a glycaemic index (GI) was attached to it."

He further pointed out that yam wasn't the only 'culprit', but most of the other local ground provisions, such as coco, dasheen, sweet potato, and so on.

Complex 'carbs'

The GI is a number attached to all foods indicating their influence on blood-glucose levels. Low GI foods, acting in the presence of high fibre levels, provide a slow release of sugar (energy). High GI foods provide a quick release of sugar (energy).

Yam and other ground provisions are loaded with complex carbohydrates. Complex carbohydrates, compared to simple carbohydrates, have a matrix of glucose molecules, break down over time and slowly release sugar into the blood. But, although yams have complex 'carbs', not all yams are equal. It is the GI that differentiates them.

In general, Bahado-Singh said all yellow yam species have a low GI index, while the white yams have a high GI index. Those with low GI indices release sugar (energy) slowly into the blood stream, while those with high GI indices release sugar much faster into the blood stream.

Jamaica's gold medal-winning relay team, (from left) Nesta Carter, Michael Frater, Usain Bolt and Asafa Powell, celebrate after the men's 4x100-metre relay final in Beijing, China, on August 22. - File

This GI classification is crucial for athletes, health-conscious people and persons with diabetes, Bahado-Singh said, as he pointed out that sprinters need a nutritional programme that provides fast energy (as in high-GI foods), while long distance, endurance runners perform better with a diet that promotes a slow release of energy (as in low-GI food).

Yam production

The Yam Research Group, the 'research baby' of Professor Helen Asemota, has been researching yam cultivation since the 1990s.

Through species identification (using DNA finger printing) and tissue culture, the group has developed and patented a method of propagating and increasing yam production by utilising the yam vine instead of the yam head.

Now, Bahado-Singh said that the group has been extending its research and has been classifying local foods based on their GI. They would like athletes, health-conscious people and those with metabolic diseases, such as diabetes, to become more aware of food's GI.

Bahado-Singh also admitted that my interview with him would cause the group to fast forward plans to start research to further explore the relationship between GI and athletic performance in Jamaica.

eulalee.thompson@gleanerjm.com.