One of the non-protein amino acids in the legume, homoarginine, is actually beneficial for humans.
Khesari dal or grass pea is nature’s gift to mankind but it should be eaten as a meal accompaniment and not as a staple. In fact, no legume should be eaten as the main course. As part of any normal diet, khesari dal can be highly beneficial.
Khesari dal has two non-protein amino acids, ODAP/BOAA (beta-N oxalyl-L-beta,alpha-diaminopropionic acid/beta-N-oxalyl-amino-L-alanine) and homoarginine The latter has been found to be a normal metabolite even in humans by various groups of researchers in the past couple of years. Its importance for human health—cardiovasculature, bone health, pregnancy—is growing.
ODAP is toxic to certain animals in high doses, but not to common laboratory animals: rats, chicks and monkeys. Humans can metabolise it completely, as we discovered in the last few years. This observation changed my perception of khesari dal and neurolathyrism. Khesari dal is safe for humans. This is evident from the latest survey in Chhattisgarh. Even laboratory animals fed khesari dal in normal quantities do not show toxicity. Much time and effort has been wasted in this futile endeavour. It is time to put an end to it.
Nitric oxide (NO) is a vasodilator. Louis J Ignarro, Robert J Furchgott and Ferid Murad, who got the Nobel prize in 1998 have demonstrated why we must say ‘Yes to NO’. In our bodies nitric oxide is generated from arginine, when proteins are metabolised. But free arginine is a very minor constituent in foods. We showed that L-homoarginine, which is present in khesari dal is a better source or substrate for sustained generation of nitric oxide because it stays longer in circulation in the body than arginine. This makes khesari dal a highly-prized commodity. It could be a boon to those engaged in endurance sports and hard physical labour because it increases blood-supply—and hence, oxygen-supply. Recent studies have shown that it could prevent strokes and improve bone health by slowing bone turnover and enhancing bone density—which means elderly people should include khesari dal in their diets. Studies have also shown that in the last semester of pregnancy there is a sharp increase in circulating homoarginine levels (as against that in the tissues). This is probably due to increased blood flow. So, eating khesari dal could provide extra levels of homoarginine in addition to what is present under physiological conditions.
While Chinese medicine has used ginseng, the cure-all herb, for ages, it has been shown recently to contain ODAP. The Chinese call it dencichine. This has rejuvenated and changed my thinking about khesari dal. We have shown that ODAP is an activator of the protein kinase C (PKC), a crucial enzyme in human metabolism. Among its many effects, is the activation of hypoxia-inducible factors (HIF) or genes to cope with low oxygen levels in the body. My colleague at Osmania University, Dr Surya Singh, was responsible for this discovery. Khesari dal can prepare you to face a hypoxic situation at high altitudes or even cope with stroke. Perhaps our brave soldiers in mountainous borders should carry khesari dal supplements. Activation of PKC also results in expression of other genes involved in neural and capillary growth.
We have also shown that ODAP is an inhibitor of the enzyme (tyrosine amino transferase, or TAT) which is associated with the metabolism of tyrosine and catecholamines. Khesari dal should produce more catecholamines (DOPA, dopamine, epinephrine) in the body. The importance of dopa, dopamine and other catecholamines for learning and memory and diseases of the central nervous system like Alzheimer’s and Parkinson’s is very well-known.
The author’s doctoral thesis was on ‘The unusual amino acids of Lathyrus sativus (Khesari dal)’. He is formerHoD (biochemistry), Osmania University