Who knew there were so many kinds of water to choose from — still, sparkling, mineral, lightly flavoured. The list goes on.

I get it — some people like bubbles, some don't. Some people find plain water bland and want a bit of flavour.

But there was one kind of water that really made me cringe. The alkaline water.

Alkaline water is one of the latest health fads to hit the market.

Supporters claim it is "super hydrating" and will balance your body's pH — and in turn slow down aging, improve your skin — and even prevent chronic diseases like cancer. Basically (pardon the pun) it's a miracle elixir.

And all for the low, low price of around $3.30 a litre!

So what actually is this alkaline water? Pure water is neutral, it has a pH of 7.

Tap water will vary a bit, depending on which different elements are dissolved in it, and have a pH between 6.5-7.5.

Alkaline water is water that has been treated, often by addition of certain minerals, to be more basic, or have a higher pH.

Supporters argue that drinking water with a higher pH will help to balance out acidity (low pH) in the body. It sounds kind of believable, right?

But you can't change the pH of your blood just by drinking alkaline water. Which is a good thing!

Our bodies maintain our blood pH within a really narrow range, at approximately pH 7.4.

Acidosis (where the pH is lower) and alkalosis (where pH increases) indicate that there are some serious health issues going on. Having some sort of respiratory obstruction, or kidney failure? Yep, that's likely to cause your blood pH to change. But drinking alkaline water? No, that's not going to shift that delicate balance.

When you look at all the claims around alkaline water and its benefits, there is little, if any, science, to back them up.

Despite this, the alkaline water market is projected to be worth around $1 billion in the next year or two. Companies are making a killing out of selling these "health benefits".

Drinking more water is probably a good idea for us all.

But you can leave the alkaline water on the shelf. The stuff that comes out of the tap will do just fine.

Dr Mary McMillan is a lecturer at the School of Science and Technology, University of New England