What Is Alkaline Water?
Alkaline water is water with a pH above 7.0 β the neutral point on the pH scale. Most naturally occurring water has a pH between 6.5 and 8.5. Commercially produced alkaline water typically has a pH of 8.0β9.5, achieved through one of three methods:
- Ionisation (electrolysis): An electric current separates water into alkaline (OHβ»-rich) and acidic (HβΊ-rich) streams. The alkaline stream is marketed as ionised alkaline water. This is the method used by high-end water ioniser machines.
- Mineral cartridge (passive alkalisation): Water passes through a cartridge containing minerals such as calcium carbonate, magnesium hydroxide, or tourmaline β these dissolve slightly into the water, raising pH and adding minerals simultaneously.
- Chemical addition: Sodium bicarbonate or potassium bicarbonate is added directly. Common in bottled alkaline water products.
The Claims Made for Alkaline Water
The alkaline water market in Bangladesh and globally makes a range of health claims. Here are the most common ones and what the actual evidence says:
Claim: Alkaline water neutralises excess acid in the body
The reality: The human body tightly regulates blood pH between 7.35 and 7.45 regardless of what you eat or drink. Your stomach immediately acidifies any alkaline water you drink to pH 1β2 for digestion. The kidneys and lungs continuously adjust blood pH with remarkable precision. Drinking alkaline water does not change your body's internal pH in any meaningful way.
Verdict: This claim does not reflect how human physiology works.
Claim: Alkaline water improves hydration
The evidence: Some small studies suggest that slightly alkaline water (pH 8.0β8.5) with added electrolytes may improve post-exercise rehydration compared to pure water. However, the effect size is modest and the benefit is likely from the electrolytes (calcium, magnesium) rather than the alkalinity itself.
Verdict: The electrolyte mineral content β not the pH β is the likely mechanism for any hydration benefit observed.
Claim: Alkaline water reduces acid reflux
The evidence: There is one reasonable study showing that alkaline water at pH 8.8 permanently deactivates pepsin β the enzyme involved in acid reflux. This is the most scientifically plausible alkaline water claim. However, the study was in vitro (test tube conditions), not a clinical trial.
Verdict: Plausible mechanism, but clinical evidence is limited. Some people with acid reflux report symptom improvement; this is a reasonable trial for reflux sufferers.
Claim: Alkaline water prevents cancer
The reality: There is no credible clinical evidence that alkaline water prevents or treats cancer. Cancer cells can thrive in a variety of internal environments; the idea that drinking alkaline water creates a cancer-hostile environment in the body is biologically unsound given the body's tight pH regulation.
Verdict: Not supported by evidence.
What Alkaline Water Actually Does Well
Setting aside the contested health claims, there are legitimate practical reasons some people prefer slightly alkaline water:
- Taste: Many people find water at pH 7.5β8.5 tastes smoother and less flat than highly purified RO water (which typically has pH 5.5β6.5 and can taste slightly sharp)
- Mineral content: Alkaline water produced via mineral cartridges adds calcium and magnesium β minerals that RO removes. This addresses a real nutritional consideration for people whose primary water source is RO-purified
- Post-exercise recovery: If you exercise regularly, the electrolyte content in mineral-alkaline water is a practical benefit independent of the alkalinity itself
Types of Alkaline Water Purifiers and Their Costs
| Type | pH Range | Method | Price Range | Notes |
|---|---|---|---|---|
| Electric water ioniser | 8.5β11.0 | Electrolysis | ৳40,000β৳2,00,000 | Most expensive; questionable if high pH is beneficial |
| RO + alkaline mineral post-filter | 7.5β8.5 | Mineral cartridge | ৳20,000β৳35,000 | Best value; also remineralises RO water |
| Countertop alkaline filter pitcher | 7.5β8.5 | Mineral cartridge | ৳2,000β৳6,000 | No RO; useful for low-TDS source water only |
| Bottled alkaline water | 8.0β9.0 | Chemical addition | ৳20β৳60 per litre | Most expensive long-term; significant plastic waste |
The Honest Recommendation
If your primary motivation is the bold anti-cancer or body-pH-changing claims, the scientific evidence does not support spending significantly more for alkaline water.
If your motivation is taste improvement, remineralisation of RO-purified water, and the modest electrolyte benefit β a standard RO purifier with an alkaline mineraliser post-filter cartridge (typically ৳500β৳800 to add to an existing system) achieves this at minimal extra cost. This is the most rational approach for most Bangladeshi households.
A pH of 7.5β8.0 with added calcium and magnesium is a genuinely pleasant drinking water β and it corrects the main practical shortcoming of standard RO water (low pH, no minerals) without the premium price of a full water ioniser.