Ah, the joys of the detox. Is it just me, or is an apple a day not enough any more to keep the doctor away? Or should that be five pieces of fruit? Maybe I should just give up. Except that now it's January, it's time for the annual cleansing of mind and body, not forgetting the soul, of course, whose conscience, after all, is as much in need of its annual injection of virtue. Since I last wrote about the benefits of the detox, the ranks of sugary, processed cordials and concentrates have been superseded by a new era of smoothies, yoghurts, oils and teas, not to mention organic berry-, root- and powder-infused health drinks with disease-resistant, energy-giving, meal-replacing, life-enhancing claims.

What was once no more than a cottage industry has grown into a fully-fledged supplier of vitamins, minerals, fibres, proteins, phenolics, fatty acids and other nutrients and anti-oxidants as yet unmentioned or undiscovered. Supermarket shelves increasingly bark health claims at us, while the likes of Fresh and Wild, Whole Foods Market and Daylesford Organics offer the full "health" monty. At the Natural Kitchen in Marylebone High Street ( www.thenaturalkitchen.com) you can indulge in green teas, wheatgrass shots and fruit smoothies with extras such as goji berries, Romanian bee pollen, Hawaiian Spirulina Powder, New Zealand barley grass powder, organic Peruvian Macaroot powder and organic flax seed oil. Phew, give me a drink someone.

Those of us with juicers at home can smugly assert that there's no need to go out and spend a fortune on the growing number of so-called health drinks now available. I wouldn't be without my own juicer, but being holier-than-thou about DIY juicing can't disguise the fact that buying your fruit, juicing it and then, the worst part, cleaning out the messy gunk afterwards, can be three operations too many in a busy working day. At least, that's what the health drinks industry is counting on.

No recommendations for a January detox should overlook the best purifying agent of them all: water. With water on the brain, before Christmas I joined a panel, including two London restaurant sommeliers and two representatives from Thames Water, assembled by Decanter Magazine to see if competing claims by Thames Water and Claridges held water, as it were. Claridges had just announced that since "water is becoming like wine", with different waters suiting different dishes, it was extending its wine list with a deluxe water list featuring 30 mineral water brands from around the world. These include 420 Volcanic from New Zealand at 50 a litre, Danish water possibly dating back to the last Ice Age and the Italian brand Fiuggi, apparently favoured by the Pope. In response, a spokesman for Thames Water said that "our water is of the highest standard and costs less than a 10th of a penny per litre".

The first thing this blind tasting proved was that tasting mineral water is not nearly as much fun as wine tasting. The differences are often so subtle that you have to have been shut away in a zen Buddhist monastery or as infallible as the Pope to be able to detect them.

In the event, Thames tap water came a very respectable fourth out of the 24 different waters tasted. Although we were all asked to name which we thought was the tap water, and which was the most expensive, no one on the panel got either right. My top marks went to Speyside Glenlivet, 5.50, at Claridges, and Veen from Finland, 3.85, and my bottom, the 420 Volcanic, which came 18th overall. To the emperor's new clothes add luxury mineral water then, and leave the rest of us to enjoy good old H2O.