Eat some <i>dal</i> (lentil) with rice

PEAS, beans and lentils are leguminous crops known as pulses. Pulses have been used as food for thousands of years. The lentil was probably one of the first plants ever to be domesticated by humans.
A relatively cheaper food, pulses are 20 to 25% protein by weight, which is double the protein content of wheat and 3 times that of rice. For this reason, pulses are sometimes called "poor man's meat."
Prices of foods have increased in Bangladesh, as elsewhere in the world. Table 1 shows changes in price of coarse rice and pulses, the major food of the poor, between 1991 and 2005.
The prices started increasing at the beginning of the year 2008, and now they are selling at Tk.35 and Tk.100, respectively. Under the circumstances, it seems that people, especially the poor, will soon have to forget the tasty and nutritious food mix of rice and dal (pulses) that they have been eating for generations.
However, if we look at the level of nutrition of pulses, then our frustration will perhaps ease out a little.
It can be seen that for an equivalent dry weight, pulses supply the same amount of calories, but more of all other nutrients except niacin, compared to rice. The difference is most marked for protein, riboflavin and calcium, the first two of which are major deficiencies in Bangladesh, and calcium deficiency is acute in some pocket areas such as Chakaria.
Lentils supply 4 times as much protein, 6 times as much riboflavin and 7 times as much calcium as rice. In Bangladesh, we eat a lot of rice, over 460 g a day. A person replacing his rice intake with pulses by 50 grams would not lose anything in terms of calories, but would gain 9.3 g of protein (required for growth and maintenance), 0.21 mg of vitamin B2 (riboflavin) (required for energy generation from foods) and 25.5 mg of calcium (required for bone formation during growth and prevention of bone loss during old age).
In addition, he would get some extra vitamin A (required for good vision and immunity to diseases). The gains are also retained for most nutrients even under the present price situation (nutrient per Taka), particularly in case of protein, calcium, and vitamin A.
The extra protein from 50 grams of lentils will not only contribute to quantitative increase in protein consumption, it will also complement the basic rice protein to give the consumer a considerable qualitative advantage. Both rice and pulse proteins are by themselves what is called "second class" protein, in that their essential amino acid profiles are not as complete as the animal proteins.
Essential amino acids, as the name implies, are those amino acids (the building units of proteins) that cannot be synthesised in the body and must, therefore, be supplied with food. Rice protein is deficient in the essential amino acid lysine, which is abundantly present in pulses.
On the other hand, pulse proteins are deficient in the essential amino acids methionine and tryptophan, which rice has in good quantities. Rice and pulses together, therefore, complement each other's proteins, and combined together the two would make complete proteins, with nutritional value as good as egg or milk protein.
In addition to nutritional qualities, pulses also have important health advantages for consumers. The recently published findings of the famous "Food Habits in Later Life" (FHILL) study undertaken in Japan, Sweden, Greece and Australia showed that the pulses are the most important dietary predictor of survival in older people of different ethnicities.
Another long-term study in seven countries -- USA, Finland, The Netherlands, Italy, former Yugoslavia, Greece and Japan (the famous Seven Countries Study) showed that legume consumption is highly correlated with a reduced mortality from coronary heart disease.

Harun K.M. Yusuf is a professor of biochemistry and human nutrition, University of Dhaka. And currently Nutrition Advisor, FAO-National Food Policy Capacity Strengthening Program, NFPCSP.