What Is Alkaline Water?
Alkaline water is water with a pH above 7 β the neutral point on the pH scale. Regular tap water typically has a pH of 6.5β8.5 depending on the source. Alkaline water purifiers and ionisers produce water with a pH of 8β10, typically through one of two mechanisms:
- Electrolysis (water ionisers): An electric current passes through the water, splitting it into alkaline (cathode) and acidic (anode) streams. The alkaline stream is collected for drinking. This is the technology used in premium units from brands like Kangen, Ionways and Tyent.
- Mineral addition (alkaline filter cartridges): Calcium, magnesium and potassium minerals are dissolved into the water after RO purification, raising pH naturally. This is the more affordable approach used in most RO purifiers with an "alkaline" stage.
The Health Claims: What Does the Research Actually Say?
The alkaline water industry makes a wide range of health claims β from anti-ageing effects to cancer prevention to improved athletic performance. Here is what peer-reviewed science actually supports, and what it does not.
Reasonably Supported Claims
Acid reflux relief: A 2012 study in the Annals of Otology, Rhinology and Laryngology found that water at pH 8.8 permanently deactivated pepsin (the enzyme responsible for acid reflux damage) in laboratory conditions. Several small clinical studies have since reported symptom relief in acid reflux patients drinking alkaline water. This is the most credible health application.
Hydration during and after intense exercise: A 2016 study published in the Journal of the International Society of Sports Nutrition found that high-pH water (pH 8.8) improved hydration status and reduced blood viscosity more than standard water after intense exercise. The effect was modest but measurable.
Bone density (theoretical): The "acid-ash hypothesis" suggests that dietary acid promotes calcium loss from bones. Alkaline water proponents argue this supports bone density. However, the body regulates blood pH tightly through respiration and kidney function β the direct impact of drinking alkaline water on blood pH and bone density is not clinically established.
Claims Without Strong Evidence
Cancer prevention: The claim that alkaline water creates an environment hostile to cancer cells is not supported by clinical evidence. Tumour cells do create a locally acidic microenvironment, but this is an effect of cancer, not a cause β and drinking alkaline water does not change the pH inside tumours.
Anti-ageing and antioxidant effects: Electrolysed alkaline water contains dissolved hydrogen gas (Hβ), which does have antioxidant properties in laboratory studies. However, the hydrogen dissipates quickly β most of it is gone within minutes of the water being produced, especially if stored.
Detoxification: The body's detoxification systems (liver, kidneys, lungs) are extremely effective at eliminating waste products and do not benefit meaningfully from the pH of drinking water.
Types of Alkaline Water Purifiers
| Type | Technology | pH Range | Price Range | Verdict |
|---|---|---|---|---|
| Electric water ioniser | Electrolysis | 7.5β11 | ৳80,000β৳5,00,000 | Most flexibility; most expensive |
| RO + alkaline mineral cartridge | Mineral addition | 7.5β8.5 | ৳18,000β৳35,000 | Practical and affordable |
| Alkaline pitcher filter | Mineral beads | 7.5β8.5 | ৳2,000β৳8,000 | Low cost; no installation |
| Alkaline inline filter (inline add-on) | Mineral addition | 7.5β8.5 | ৳1,500β৳4,000 | Add-on to existing RO system |
The Important Caveat: Alkaline Water After RO
Standard RO purifiers produce water with a slightly acidic pH (5.5β6.5) because the membrane removes the buffering minerals (calcium, magnesium bicarbonates) that naturally maintain pH. This RO water is not harmful, but it tastes flat and some people find the low pH unappealing.
A mineraliser or alkaline cartridge stage added after the RO membrane:
- Raises pH to 7.5β8.5 β within the comfortable drinking range
- Re-adds calcium and magnesium β improves taste and provides mineral benefits
- Costs ৳400β৳800 per cartridge replacement annually
This is the most practical approach for Bangladesh households β get clean water from the RO stage, then restore a pleasant pH and mineral content with a post-RO alkaline cartridge.
Is an Alkaline Purifier Worth Buying?
For general household use: A standard RO purifier with a mineraliser/alkaline post-cartridge (available in most mid-range and premium units) gives you clean, slightly alkaline, mineral-enhanced water. This is the sweet spot β good water quality at a reasonable price.
For acid reflux sufferers: The evidence for pH 8.8+ water and acid reflux relief is credible enough to try. An alkaline cartridge in your existing RO system is the low-cost way to test whether it helps you.
For premium electric ionisers (Kangen etc.): The price premium of ৳2,00,000β৳5,00,000 over a standard RO purifier is very difficult to justify based on current evidence. You are paying primarily for marketing and brand positioning, not for verified health outcomes that a ৳25,000 RO purifier with alkaline cartridge cannot achieve.
The honest recommendation: Buy the best RO+UV purifier you can afford for water safety and purity. Add a mineraliser/alkaline post-cartridge for better taste and a modest pH improvement. Ignore the premium ioniser market unless you have a specific medical recommendation from a physician.