Is reverse osmosis water healthy? Minerals, pH levels and common myths

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Reverse osmosis (RO) removes almost all dissolved substances from the water – including minerals such as calcium and magnesium. That is why you often hear people say: ‘RO water is too stripped of nutrients’, ‘it depletes the body of minerals’ or ‘it is acidic’. Is there any truth in this?

Summary

RO water contains very few minerals. However, the body obtains the majority of its minerals from food, not from drinking water.
The claim that RO water ‘deprives’ the body of minerals is not substantiated in the context of a normal diet.
The pH of RO water is often slightly below 7 because carbon dioxide is dissolved from the air. This poses no health risk – the body regulates its own pH level.
For those who prefer a fuller flavour: the TLW 7 comes as standard with a mineralisation cartridge containing Sango coral; for the TLW 4, this can be added as an optional extra.

1. Where does the body get its minerals from?

With a normal diet, calcium, magnesium, potassium and other minerals come mainly from foods such as vegetables, tempeh and tofu, fish, nuts and dairy products. Tap water or mineral water usually contributes only a small proportion of the daily requirement. Anyone who eats a varied diet will meet their requirements even when drinking water low in minerals.

In its publications, the World Health Organisation (WHO) discusses whether drinking water that is very low in minerals over the long term could be detrimental if combined with an unbalanced or inadequate diet. It does not specify a mandatory minimum mineral content for drinking water.

2. ‘RO water depletes the body of minerals’ – is that true?

No, not in the sense that is often claimed. Water we drink is immediately mixed in the body with saliva, gastric juice and food. It does not ‘leach’ minerals from bones or tissues. Mineral balance is regulated by the kidneys and the gut.

3. Is RO water too acidic?

Pure water absorbs carbon dioxide from the air. As a result, the pH of RO water often drops slightly below 7. By way of comparison: coffee, tea, fruit juices and soft drinks are significantly more acidic. The stomach is highly acidic anyway, and the body maintains a constant pH level in the blood regardless of what you drink. A slightly acidic pH level in RO water is therefore not a health concern.

4. The health benefits of RO water

The real benefit of RO is what is no longer in the water: the membrane filters out the majority of dissolved contaminants such as heavy metals, nitrate, pesticide residues and microplastics, as well as bacteria and viruses. This is particularly important when the quality of tap water fluctuates or there are old pipes in the house.

5. Mineralisation: for the taste

Some people find water that is very low in minerals to taste ‘flat’. The TLW 7 is therefore always fitted with a mineralisation cartridge made from Sango coral, which adds some minerals back into the filtered water. This slightly alters the taste and pH level. If you do not want this, simply remove the cartridge – this is actually better for kettles and coffee machines, as otherwise limescale can build up again. Mineralisation can be added to the TLW 4, but not to the TLW 2.

Conclusion

RO water is perfectly safe to drink as part of a normal diet. Minerals come primarily from food, the slightly acidic pH level is harmless, and the benefit lies in the fact that harmful substances are filtered out. If you prefer a rounder taste, you can add a mineralisation stage. Any questions? Message us on WhatsApp.