When you visit Rwanda, the first thing you will realise most menus contain chips, rice, ubugali and sweet potatoes (though on a smaller scale). And much as the menu may also contain other food items, you can tell — even by mere observation - that yams are not one of their delicacies. Experts, however, warn that skipping yams may not be a very good idea given the rich nutrients it contains.

"Yam is a good source of complex carbohydrates and provides calories without necessarily raising the blood sugar level to cause worry for even the diabetics,” says Dr Rachna Pande, a specialist in internal medicine at Ruhengeri Hospital.

She adds that apart from its energy benefits, a high proportion of yam flesh has fiber which is important for proper bowel movements hence reducing the risk of constipation and colon cancer.

"Yams are high in fiber and once eaten improves digestion thus minimizing complications that may result from constipation and colon cancer,” Pande explains.

Protective nutrients

The flesh of yams is rich in protective nutrients mainly vitamins C, A and majority of B group vitamins.

"Vitamin B complex participates in many metabolic functions of body but besides this, the vitamin works to maintain a healthy nervous system. On the other hand, vitamin C present in yams helps to improve resistance against diseases,” she adds.

Other vitamins such as A which appears in its precursor form of betacarotene are responsible for improved eye sight although sometimes they may be associated with reducing wear and tear of the body.

Nonetheless antioxidant properties of the vitamins derived from the yams have been associated with improved fight against cancer and enhancing both cardiovascular and brain function.

Recent studies published in the American Journal of Chinese Medicine show that yams have the ability to increase learning and memory capacity in the human brain.

According to the study, after six weeks of yam intake, there was significant increase in the cognitive abilities of the subjects. It is believed that the unique anti oxidant enzymes present in yams are responsible for the increased cognitive response.

From this study, it is also believed that yams may have an effect on controlling Alzheimer’s disease.Minerals and body functions

Audrey Mutabazi, a food consultant, says that besides the vitamin content, yams are rich in minerals that people should not miss if they are to ensure proper growth and development.

"Minerals such as calcium, iron, copper and manganese are useful for the body’s health in various ways such as bone growth and development,” Mutabazi says.

He adds that much as yams contain less proteins than sufficiently required for muscular construction, their deficiency in fats compensates for the risks that would be incurred when consumed by people with cardiovascular difficulties.

"Excess dietary fat may clog blood vessels and lead to cardiovascular problems. However yams only contribute 0.0005g of fat per 100g which is almost negligible to cause harm in the blood vessels,” Mutabazi adds.

Meanwhile, the copper present in the yams also helps the body during the manufacture of proteins such as hemoglobin for blood cells, elastin and collagen fibers.

The potassium present in the yams is involved in vital functions which include energy production, muscles contraction and nerve impulses.

However, yams should never be eaten uncooked since they contain many naturally-occurring plant toxins including dioscorin, diosgenin and tri-terpenes. They must be peeled and cooked in order to remove these bitter proteins.

Unlike most foods, yams are indigenous to Africa and have been grown on the west coast since slave trade.

From Africa, yams became staple foods on plantations in the Caribbean and are now common in Jamaica. Over 18 different varieties of yam are cultivated in Jamaica before finding their way out as exports to Indian communities in the United States, Canada and Great Britain.