RO Water--What Are We Missing

 (This is a work in progress. I'll be back)

There's been a lot of talk on the web about distilled water and RO water being bad for you, leaching minerals from the body, cause heart disease and all that. Although we filter out most of what we read in the tabloid press and web, perhaps there is a kernel of truth, hear and there, accidentally, it seems. As I begin researching drinking water filtration for a serice of up-coming articles, I find there is substance to to concern over the lack of substance in pure water. While I'm not a health researcher, there is enough scholarly work out there by respected organizations to take seriously. I like reading things from the World Health Organization (WHO).

WHO Symposium on Low-mineral water.
WHO paper.

Please read these at length. Google strings with "drinking water," magnesium," and "calcium." Try to read between the fluff and ignore all sites that are selling something.

There are many concerns; the three that seem best supported by science are:

• Heart Disease. A shortage of magnesium is well correlated with certain forms. Also stroke.
• Kidney Stones. It seems that dietary supplements increase risk, while calcium in the water decreases the risk. Different absorption mechanism.
• Heavy Metal Absorption. If there is enough calcium in the system it out-competes many toxic materials. In fact, precipitation with lime is the basic industrial treatment for most heavy metals.

It seems all of that traditional stuff about healthful mineral waters had substance. Funny how that happens. Funny how your parents get smarter over the years.

What does this mean to the sailor?
 

Even though single-stage RO water (typical sailboat water maker) is not ultra low in Ca or Mg, it is considerably lower than most surface waters and lower than the general guidance available to us. I'm not sure what this means at a practical level. If you swim enough swallow a few mouthfuls of seawater, that's actually a good thing (a few percent seawater will solve the problem). Bottled water helps. Supplements may, but a dash of seawater in the cooking is simpler!

For coastal sailors I think the message is clear; using dock water with some on-board treatment (I'm researching that) is a better bet than running a water maker.