A not so commonly-eaten vegetable, yam is a starchy tropical tuber high on carbohydrates. It is like potatoes and sweet potatoes, though not be confused with either. Loaded with nutrients specially fibre, yam has made it to the list of foods suited for management of weight, diabetes and blood cholesterol levels. Native to Africa and Asia, yam is commonly known as zimicand in India. Several varieties of yam are available. In Indian traditional medicine, the tuber is used as an aphrodisiac and antidiabetic.
The nature of carbohydrates in yam differ from that of potatoes. Its high fibre content contributes to a glycemic index of 54, significantly lower than that of potatoes having a glycemic index of 80. This makes yam better suited for weight watchers, diabetics and those with heart disease as it does not create sharp increase in insulin response.
A 2013 animal study in the British Journal of Medicine and Medical Research reported that intake of yam extract led to reduced food intake, blood glucose level and body weight. The benefits of yam go beyond this.
Several varieties of yam contain steroids (hormone like substances) and alkaloids, plant substances that possess powerful physiological effects. Some of them have also been used to prepare oral contraceptives and medicines for arthritis.
Yam has, interestingly, also been used to treat menopausal symptoms. A 2005 study in the Journal of American College of Nutrition investigated the effects of yam intake on lipids, antioxidant status, and sex hormones in 24 healthy postmenopausal women. The women replaced their staple food (rice for the most part) with 390 g of yam in 2 of 3 meals per day for 30 days. Researchers observed that intake of yam led to increased serum concentrations of estrogen and decreased cholesterol levels. Although the exact mechanism is not clear, replacing two thirds of staple food with yam for 30 days improves the status of sex hormones, lipids, and antioxidants.
These effects may also have a potential to reduce the risk of breast cancer and heart diseases in postmenopausal women.
In addition, Yam is a good source of fibre, vitamin C, B6 and micronutrients like manganese, copper and potassium. Overall, yam is a healthy source of carbohydrates. Remember to watch your portions and substitute these for other carbohydrates and don’t go overboard! Further research on yam and its health benefits could yield great therapeutic effects in management of menopausal symptoms, diabetes and obesity.