My nieces and nephews have babies and the mid-wives seem to be telling all these new parents never to give a baby water. I thought everyone needed water? What is that all about?
Although I agree with you that we all need water, I have to say that I do understand why some mid-wives (as well as some pediatricians) would say "no" concerning water to babies for a few reasons:
Digestive Health. In preparation for my 5 part blog on hydration, I studied on the sensitive nature of the ph balance of the stomach with respect to digestion. Babies which are still developing this acid / alkaline balance could be more affected long term if this balance does develop properly. Issues like allergies and eczema could be directly related to this.
Lastly, Sodium / Potassium Balance. Remember that there are two bodies of water in the body. Outside of the cells and inside of the cells. Just because we put water into our bodies does not automatically mean it gets into our cells. I don't want to over-simplify, but basically, the exchange of nutrient-filled water into and waste-filled water out-of our cells is what makes hydration. This happens with the exchange of inward sodium and outward potassium in an "electric" type of exchange. We know the dangers of too little water, but too much water can cause water intoxication by diluting this balance.
There is more to this but these seem to be the main concerns, but in all transparency, my wife and I held off on giving water until four months and in retrospect studying this further, I probably would have pushed that back to six months. I'm certainly not saying that all babies would have issues with this, especially with just sipping or through the summer months, but I have to agree that there is enough evidence for this to be a valid concern.
Eating Well for Good Health (lesson 6), Valeria Menza
Water Intoxication - a Dangerous Condition, Gosta Samuelson
Scandinavian Journal of Nutrition 2003; 47, Taylor & Francis ISSN 1102-6480