Demineralized water is “thirsty” - it’ll suck the nutrients you need in water from your food and from your body when you drink it.
The body needs a certain amount of minerals and nutrients on a daily basis to stay healthy and operate normally. Some of those minerals come from food. Others, however, need to be absorbed through water. They include calcium, which is essential to the health of our bones and teeth, and magnesium, which is used nearly everywhere in the body.
Distillation processes remove those minerals from water - the demineralized water that's produced is referred to as "soft." It happens at desalination plants, where water is sometimes remineralized after salt and other minerals are removed. It also happens when you filter your water through a product like a Brita filter. Although home use of filters is unregulated, different regulatory bodies have varying standards for the levels of minerals that water from desalination or treatment plants needs to have.
Soft water is thirsty - it wants to have minerals and will leach those minerals from surrounding sources. A report published in the Medical Journal of the Armed Forces of India found that cooking with soft water leached significantly more minerals from vegetables than cooking with hard (mineralized) water.
The World Health Organization's white paper on demineralized water describes a similar effect in the human body. Not only does soft water lack the minerals and nutrients that our body needs from water; it reabsorbs those minerals inside of us. If you're getting calcium from milk, for example, soft water might suck that calcium back out of your system. That's particularly worrying in adolescents, whose bones are still growing, and in elderly women, who are at higher risk of conditions like osteoporosis.
There are important and legitimate reasons to filter water - not everyone has access to clean water with a healthy level of minerals, and many sources have been contaminated with genuinely dangerous chemicals. If you're filtering your water without good reason - out of an abundance of caution, or the mistaken belief that chlorine in the water supply is slowly killing you - you may want to re-examine your mineral intake and consider alternative methods of getting clean water that hasn't been stripped of the minerals that you need.
- Leaching of important minerals from food
- Leaching of important minerals from the body
- Does not have the calcium or magnesium your body needs
- Could increase risk of osteoporosis or bone fractures