Lentil is a small legume seed belonging to the Lens culinaris species and the Leguminosae (Fabaceae or Papilionaceae) family. It is one of the world most ancient food crops, has a lens shape, exist as a spectrum of colours, which includes yellow, orange, red, green, brown or black. Lentil is classified as a pulse with other legume seeds such as pea, chickpea, and dry beans. Pulses, such as lentils, contain approximately twice the amount of protein per gram than whole-grain cereals like wheat, oats, barley, and rice. About one-third of the calories in lentils come from protein, making it one of the highest level of protein by weight of any legume or nut.
Lentil protein, like other pulse proteins, is a good source of the essential amino acids, particularly leucine, lysine, threonine, and phenylalanine, but is deficient in the sulphur-containing essential amino acids methionine and cysteine. Cereal grain proteins on the other hand are rich in methionine, but low in lysine. Hence, a lentil–rice or lentil–wheat combination provides a complete protein profile of all essential amino acids.
Nutrition profile of lentils
The composition of lentils is approximately 28% protein, 63% total carbohydrate (47% of which is starch and 12% dietary fibre), and only about 1% fat. Lentils also contain a wealth of micronutrients with vitamins such as thiamin, riboflavin, niacin, pantothenic acid, vitamin B6, and folate) and minerals (predominantly iron, phosphorus, zinc and calcium) plus a significant content of polyphenols.
There has been an increased interest to the study of lentils as a functional food due to their nutritional composition, their nutritive value and the presence of phenolic bioactive compounds that play a vital role in the prevention of degenerative diseases in humans (such as diabetes, obesity, cancers) and a significant role in improving health.
According to Kumar Ganesan and Baojun Xu, lentil is a potential functional dietary ingredient which has polyphenol-rich content; the seed coats of lentil have a high amount of flavan-3-ols, proanthocyanidins and some flavonols. The polyphenol-rich lentil seeds have antioxidant potential and a primary function in protecting against various diseases such as diabetes, obesity, CVD and cancer, when consumed regularly.
Nutritional Health Benefits Associated with the Consumption of Lentils.
Kumar Ganesan and Baojun Xu reported that a recent study concluded bioactive compounds in lentil (legumin, vicilin and convicilin) possess higher antioxidant and cardioprotective activity. Also, red lentil protein hydrolysates could contribute to the blood pressure-lowering effects of lentils.
A report from an in vivo study concluded that administration of lentils actively reduces the total cholesterol, triglycerides, low density lipoprotein and pathological manifestations of cardio-morphometric analysis, hence supporting the importance of lentil seed as a therapeutic potential for hypertensive patients.
It has been strongly suggested that eating pulses is beneficial in the prevention and management of diabetes. Lentil-derived leguminous fibre have been found to prevent the impairment in the metabolic control for diabetic rats when total carbohydrates intake was increased, suggesting that lentil carbohydrates, including their dietary fibre, could have promising implications for diabetic patients. In a study report, it was found that adding 50 g of cooked lentils to diabetic patients regular diet led to a significant decrease in fasting blood sugar and glycemic index; the regular consumption of lentils significantly decreased serum blood glucose. The authors of the study explained, the “reductions of the glycemic index from the diet are due to the presence of polyphenols in the lentils that have been linked with health-promoting impacts on metabolic disorders such as diabetes, obesity”.
Kumar Ganesan and Baojun Xu reported that the intake of lentils is inversely connected with the incidence of obesity; Lentil seeds are rich in fibre, fibre enhances satiety and lowers the amount of food intake, which lead to maintaining body weight in some individuals.
This is consistent with other studies that reported an inverse relationship between pulses intake and BMI or obesity risk.
The consumption of lentil seeds has been associated to a reduced risk of developing some cancers including colon, thyroid, liver, breast and prostate. Lectins and phenolic compounds derived from lentil seeds seem to be interesting therapeutic agents against tumorigenesis or cancer cell agglutination and/or aggregation.
Kumar Ganesan and Baojun Xu reported it is the high polyphenolic content of lentil seeds that could potentially prevent carcinogens; this happens through chemo-preventive activities, including the uptake of carcinogens, activation or formation, detoxification, binding to DNA and DNA repair activities. This is combined with lectins in lentils which have anticancer properties. The reported mechanisms of action of lectins along with phenolic compounds in lentil seeds potentially bind to cancer cell membranes/receptors, causing cytotoxicity, apoptosis and autophagy; thereby, they inhibit the growth of tumours.
Lentils also contain the mineral iron; some studies have shown that the consumption of cooked lentil in the diet prevents iron deficiency anaemia, iron being a very important mineral, which is required daily, especially for adolescents and pregnant women.
Individuals can use brown, green, or red lentils in their diet in a variety of ways.
● Brown lentils are the cheapest and soften the most upon cooking. They work best in soups and stews
● Green lentils have a nuttier flavour. They stay firm when cooked and make good salad or taco toppers.
● Red lentils have a milder taste. They are great for bulking out curries and purees and are also soft when cooked.
Unlike dried beans, lentils do not require soaking and they cook in just under 20minutes.
Some simple and tasty ways to include lentils in the diet:
● Add lentils to any soup or stew recipe for extra nutrients and fibre.
● Precook lentils, and keep them in the refrigerator as a quick protein source.
● Lentils can be used instead of beans in any recipe.
● Red lentils can be used as a substitute for red meat in a Bolognese sauce or lasagna recipe.
● Make a lentil dip by smashing cooked lentils with a fork and adding garlic, onion, chilli powder, and chopped tomatoes.
● Look out for new snacks and foods, such as lentil based crackers or chips and lentil pasta.
Consuming large amounts of fibre may cause flatulence and constipation.
Any person increasing their fibre intake should:
● drink plenty of liquids to prevent constipation
● consume small amounts of fibre at each meal
These tips can help prevent digestive discomfort as the body adjusts to the fibre increase.