Get your chloro-fill: Swetha Sivakumar on leafy greens

Your grandparents can probably identify dozens of leafy greens. You, on the other hand, can hopefully tell methi from moringa from palak. Bathua, lauki leaves, ponnanganni keerai? It feels like, with every generation, there is a narrowing of the selection of greens sold by vendors, and consequently recognised, cooked and eaten in city homes.

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We can thank the industrialisation of our food supply chains for this. It has made many things much easier, but others, no longer worth the effort. Tender greens wilt in intense heat, and last just a few days refrigerated. When competing for shelf space in a supermarket, they invariably lose out to hardier staples.

The truth is, our diets have been narrowing for millions of years. We no longer eat many insects and animals we once relied on for survival; we shun parts that were once prized, such as offal. Meanwhile, of the estimated 200,000 species of plant that are technically edible, we eat only about 200. We’ve ruled out many based on factors such as flavour, easy availability and shelf life.

Some were edible but unfeasible to begin with. Any leaves high in cellulose, for instance, were avoided even by prehistoric humans. We lack the enzymes to digest such plants, which include grass, pine needles and spiky leaves such as those of the pineapple.

Among the greens that we do eat, some contain chemical-defence compounds that are meant to discourage animals from eating them. These can cause unease in humans; some can lead to severe illness.

Even spinach leaves generate oxalate crystals; turnip leaves produce goitrogens; cassava leaves contain trace amounts of cyanide. The chemicals can be deactivated or eliminated if the vegetable is cooked correctly. But this adds another element of complexity to dealing with unfamiliar greens.

Add to this the fact that most recipes contain fewer than six ingredients. In India, leafy greens are tossed with just oil, ginger, garlic, turmeric and chillies, be it saag from Punjab, haak from Kashmir or choddo shaak from Bengal. The list is similarly brief in recipes for ghormeh sabzi in Iran, the Mediterranean horta and the southern American collard greens. The flavour is meant to come from the leaf. Which means one must know exactly what to do with it, or the results could be bitter, flavourless, dry.

Start by picking the right greens (tender and therefore less bitter). Sticklers will only eat certain ones in certain months, and they’re not wrong. Leafy greens tend to be sweeter in winter and spring, before they age or yellow. Cooler temperatures also mean fewer pests, and therefore fewer defence chemicals. Certain leaves turn bitter when flowers appear on the plant. Scientists believe this may be an added protection mechanism against predators, at the crucial pollination / reproduction stage. So know your plant.

The next step is cooking it just right. The oxalates in greens, left to themselves, can leach calcium from the human body. Research shows that immersing the leaves in hot water reduces the levels of these bitter, water-soluble defence chemicals far more effectively than steaming or baking. So blanching is essential. There are other ways to neutralise the oxalates. An interesting example comes from a traditional Indian recipe: palak paneer. We are now learning that the calcium in the paneer combines with the soluble oxalate in the palak to form an insoluble calcium salt that is less likely to be absorbed by the body, rendering the spinach safer.

Even with the oxalates tackled, the bitterness sometimes persists. In some cultures, it is simply embraced. On festivals such as Ugadi or Yugadi, the Hindu New Year in large parts of the south (usually celebrated in late March or early April), bitter neem leaves and flowers are added to a pachadi. It’s a great recipe for gut health, and a reminder that it is often a good idea to make room for a little bit of hardship, in exchange for good health or good fortune.

(To reach Swetha Sivakumar with questions or feedback, email [email protected])