Lettuce is often grown as a leafy vegetable, but sometimes, for its stem and seeds.
The leafy vegetable is always eaten as a salad or used as a food wrap. It’s crunchy with a mild sweet taste, green in colour.
In the local Rwandan market, the price ranges from Rwf 400 to 500 for a single bunch.
According to Joseph Uwiragiye, the head of nutrition at University Teaching Hospital of Kigali (CHUK), lettuce leaves are one of the biggest sources of essential nutrients important for one’s health.
He says in most cases, lettuce is used in sandwiches, bread, and salads, and is a very low-calorie green vegetable.
For instance, he says 100g fresh green lettuce provides just 15 calories.
VITAMINS AND MINERALS
Uwiragiye says that they contain phytonutrients that possess health-promoting and disease prevention properties.
“Vitamins in lettuce are plentiful. Its fresh leaves are an excellent source of several vitamins — A and β-Carotene,” he says.
According to Uwiragiye, these compounds have antioxidant properties. Vitamin A is required for maintaining healthy skin and is also essential for vision.
He notes that the consumption of natural fruits and vegetables rich in flavonoids, including lettuce, helps to protect the body from lung and oral cavity cancers.
Erick Musengimana, a nutritionist at Rwanda Diabetes Association in Kigali, says lettuce is a rich source of vitamin K.
He explains that Vitamin K has a potential role in bone metabolism where it is said to increase bone mass by promoting osteoblastic activity in the bone cells.
Besides, Musengimana says, it also has an established role in Alzheimer’s disease by limiting neuronal damage in the brain.
“Fresh leaves of lettuce contain good amounts of folates and vitamin C. Folates are part of co-factors in the enzyme metabolism required for DNA synthesis and, therefore, play a vital role in the prevention of the neural tube defects in the baby (foetus) during pregnancy,” he says.
Moreover, Musengimana says, vitamin C is a powerful natural antioxidant, and that regular consumption of foods rich in vitamin C helps the body develop resistance against infectious agents and scavenge harmful, pro-inflammatory free radicals.
Studies show that zeaxanthin, which is an important dietary carotenoid in lettuce, is selectively absorbed into the retinal macula lutea, where it is thought to provide antioxidant and filter UV rays damaging the retina.
Diet rich in xanthin and carotenes is believed to offer some protection against age-related macular disease in older adults.
Uwiragiye says the vegetable also contains healthy amounts of minerals like iron, calcium, magnesium, and potassium, which are very much essential for body metabolism.
“Potassium is an important component of cell and body fluids that helps controlling heart rate and blood pressure. The body uses manganese as a co-factor for the antioxidant enzyme, superoxide dismutase,” he says.
It is also rich in the B-complex group of vitamins like thiamine, vitamin B-6 (pyridoxine), riboflavin.
He says regular inclusion of lettuce in salad is known to prevent osteoporosis, iron-deficiency anaemia, and believed to protect from cardiovascular and cancer diseases.
PREPARATION AND STORAGE
He says it’s important for one to go for leaves that are bright in colour and fresh, and that they should avoid sunken leaves with spots or discolouration.
He adds that each variety of lettuce features a unique keeping quality; hence, different methods should be applied in storage.
When it comes to storing, he says it’s essential to wash them thoroughly and drain any excess water before storing in the refrigerator or in a clean place.
Alternatively, Musengimana says soaking them in saltwater for a few minutes is important because it helps remove sand and parasite eggs and worms.
Then, washing leaves in clean running water is also essential.