What Your RO Removes

The practice. Curd churned with water until the butter rises and is lifted away, then the thin, sour liquid left behind is salted, often with roasted cumin, a little ginger, a few curry leaves. In Gujarati and Rajasthani homes it closed the midday meal; further south a thinner version was poured over the last of the rice. Made fresh each morning, drunk at room temperature, never kept long.

What the research says. Chhaas carries what curd carries, diluted — calcium, potassium, phosphorus, a little protein, and the live lactic acid bacteria of fermentation. Reviewing the evidence in 2010, the European Food Safety Authority accepted that live yoghurt cultures improve lactose digestion in people who digest lactose poorly, one of very few fermented-dairy claims to clear that bar. Honesty matters here: because chhaas is curd let down with water, mineral density per glass sits well below curd’s, and household cultures are unnamed and unmeasured.

Before you start. Salt is the variable worth watching — a heavily salted glass twice a day adds up for anyone told to keep sodium down. Make it fresh; curd left standing in warm weather turns sharp quickly. Many people find it sits well after a heavy meal. If dairy troubles you, this will not be the exception.

The practice. A green coconut, the crown shaved off in three strokes, the shell tipped straight to the mouth. Along the Kerala and Konkan coasts, through Tamil Nadu and coastal Andhra, it was less a drink than a fact of the afternoon — sold at the roadside, drunk in the heat, the soft malai scraped out afterwards with a sliver of the husk. Nothing added. Nothing kept.

What the research says. Tender coconut water runs roughly 250 mg potassium, 105 mg sodium, 25 mg magnesium and 24 mg calcium per 100 ml, alongside about 2.6 g of sugar. Small randomised crossover trials in Malaysia found it restored body weight after exercise-induced dehydration about as well as a commercial sports drink, and was easier to keep down. Its sodium is low for heavy sweat losses, which is precisely why one of those studies had to add salt to match.

Before you start. Choose it tender and drink it fresh; once opened it ferments within hours. The potassium that makes it interesting also makes it a genuine caution for anyone with kidney disease or taking potassium-sparing medication — published case reports of dangerously high blood potassium exist. It carries sugar too, so treat it as a drink, not as water.

The practice. A lump of gud dissolved in a glass of water, sometimes with lemon and a pinch of black salt, drunk in the fields at noon or handed to anyone who had walked a long way in the sun. Through Maharashtra, Uttar Pradesh, Bihar and across the sugarcane belt, it was the everyday answer to heat and a long morning — cheap, sweet, and already in the house.

What the research says. Worth stating plainly: jaggery is largely sugar, running 65 to 85 per cent sucrose. The widely repeated figure of about 11 mg iron per 100 g is both variable and partly incidental, some of it arriving from the iron pans the cane juice is boiled in. A realistic 10 g piece gives roughly 1 mg — near a twentieth of an adult Indian woman’s daily requirement. Jaggery keeps minerals that refining strips out. It is not an iron supplement.

A note of caution. Jaggery is still sugar, and the body largely treats it as such. If you live with diabetes or are watching blood glucose, leave this one alone without your doctor’s word. For everyone else, keep the piece small, think of it as a sweet drink rather than a mineral one, and keep plain water going alongside.

The practice. Roasted chana ground to a fine flour, whisked into cold water with salt, lemon and green chilli, or with gud when a sweet version was wanted. This is Bihar’s drink above all, and eastern Uttar Pradesh’s — carried in a cloth bundle, mixed at a well or a tap, drunk at eleven in the morning by people who would not sit down to eat again until evening.

What the research says. Chana sattu runs roughly 20 g protein, 15 g fibre and 58 g carbohydrate per 100 g, with around 800 mg potassium, 300 mg phosphorus, 170 mg magnesium, 70 mg calcium and 5 mg iron — which is why it behaves like food rather than like a drink. That iron is non-haem and absorbed less readily than iron from meat, though the lemon traditionally squeezed in supplies vitamin C, which is well established to improve non-haem absorption.

Before you start. Two or three tablespoons in a tall glass is plenty; more sits heavily, and the fibre can bloat anyone unaccustomed to it. Use sattu that still smells freshly roasted — it goes rancid quietly. Mix it thoroughly, drink it soon after, and count it as part of a meal rather than as something on top of one.

The practice. Amla grated or crushed into water, sometimes with a pinch of salt, sometimes as the pressed juice of two or three fruits let down in a glass. In winter, when the fruit came in, homes across north India kept it going through the season. The taste is much of the point — sour first, bitter behind, and then a strange sweetness on plain water afterwards.

What the research says. Measured across cultivars, amla runs somewhere between roughly 190 and 720 mg vitamin C per 100 g of fruit — a wide range, worth knowing before trusting any single headline figure. Much of its antioxidant activity is not vitamin C at all; laboratory work identifies gallic acid, ellagic acid, quercetin and rutin among the major contributors. And a glass made from a spoonful of juice or powder carries far less than those per-100 g numbers imply.

Before you start. Amla is acidic; many people find it easier taken with food, and gentler on the teeth if you rinse with plain water afterwards. Fresh fruit is preferable to bottled juices, which often carry added sugar. Concentrated extracts are a different proposition at a different dose — if you take medication regularly, ask your doctor before making a daily habit of those.