If you want water with wow you don’t need to look far. Shop shelves are filled with “enhanced” waters to help meet your daily vitamin and mineral intake, unlock your energy, or even aid you in relaxing. But some of these products are so acidic they risk doing serious damage to your teeth. We tested the pH of 19 drinks and looked at their claims.

Zero Water states it has zero sugar, carbs or artificial sweeteners, Mizone Sports Water claims it’s “easy to hydrate” with its great tasting blend and Sequa Relax claims it’s a “nutritionally researched formula”. But these drinks, marketed as healthier options because they contain smaller quantities of sugar or none at all, are still bad for your teeth because of their acidity.

We tested the pH of 19 drinks to see how acidic they were. A pH of 7 is neutral (for example, tap water); the lower the pH, the more acidic the drink. A pH less than 5.5 increases the risk of dental erosion. The majority of products in our test had a pH below 5.5.

Eight of the drinks contained citric acid, naturally present in oranges and other fruit, and added to beverages as a preservative and for flavour. The most acidic drink was Pure NZ Herbal Sparkling Drink, which had a pH of 2.7. The manufacturer said the drink’s been discontinued but we were able to find old stock in a Wellington supermarket.

Next were Ch’i’s sugar-free offering and OVI Hydration Citrus (it contains ascorbic acid), both with a pH of 2.9. That compares with 2.4 for Coca-Cola.

Five others — VitalZing Water Drops Lemon Lime, Vitasport Water Booster Lemon Lime, Mizone Sports Water Lime, Glaceau Vitamin Water Dragonfruit and Caliwater Cactus Water (it contains lemon juice) — were more acidic than the Keri Orange Juice we tested as a comparison.

The only drinks that had a pH above 5.5 were Pump Water, H2Coco Coconut Water Cocoespresso and Ararimu Valley Alkaline Water. The two plain coconut waters we tested had a pH of 5.4.

New Zealand Dental Association senior oral health educator Dr Deepa Hughes says the acidity of drinks is a hidden danger. “We should drink plain water, not sugary or acidic drinks for hydration. Any other drinks, even if they have ‘diet’ or ‘water’ in their name are best for occasional treats,” Dr Hughes says.

But if you believe the hype on the packaging of some products, you’d think there was something wrong with drinking plain water.

Just relax

“Press pause and unlock a calmer, more centred you.” That’s the blurb on a can of Sequa Relax — a “wellness lifestyle” drink. A promotional brochure for the drink includes claims it “reduces muscular and nervous system tension and helps improve your sleeping habits”. The product website also has anecdotes from people who said Sequa Relax had been life-changing and helped improve sleeping patterns.

The drink claims to be a nutritionally researched formula and it’s marketed as a functional beverage. According to manufacturer The Great Beverage Company, the drink’s effectiveness is due to its “10 active ingredients”, which include liquorice root, panax ginseng and magnesium citrate. But how much of these ingredients are present isn’t stated.

After we contacted the company, it conceded the promotional brochure claiming health benefits for the drink was “released into the market in error” and the remainder of the 4000 fliers would be destroyed. “The brochure was, regrettably, not fully reviewed prior to being sent for printing,” it said.

Coconut water

Coconut water — not to be confused with coconut milk — is the clear liquid inside young green coconuts and we’re chugging it down in increasing volumes. According to Nielsen Scantrack data, we spent nearly $13 million last year on coconut water in supermarkets, an increase of 146% in two years.

Coconut water’s main claim to fame is as a sports drink alternative. Many products state they contain natural electrolytes, ingredients that sports drinks also boast. One of the star electrolytes in coconut water is potassium – most products in our survey had 400 to 500mg per glass.

But Dietitians NZ member Lea Stening says there are better sources of potassium. For example, a banana has 400mg of potassium plus carbohydrates and dietary fibre. “You can also get potassium from meat, fish, whole grains, vegetables, milk, eggs and cheese,” she says.

Although coconut water has fewer kilojoules than fruit juice or sports drinks, it still contains natural sugars, which contribute to energy intake.

Then there are the flavoured varieties, which tend to have even more sugar. H2Coco Coconut Water Cocoespresso has more than four teaspoons of sugar per glass, which includes natural sugars and added cane sugar.

Cactus water

Another water fad is cactus water. Cactus water is made from the prickly pear cactus plant. Caliwater Cactus Water and True Nopal Cactus Water tout cactus water as having fewer kilojoules and sugar than coconut water plus it contains betalain antioxidants.

Caliwater’s website claims betalains are rare and potent antioxidants that help revitalise skin and fight signs of ageing. After we contacted the company, it removed this health claim.

True Nopal Cactus Water claims studies on prickly pear cactus have shown the plant can decrease inflammation associated with exercise. We asked for evidence.

The health claim for True Nopal isn’t approved and the company hasn’t met the requirements of the Food Standards Code for a self-substantiated claim (see “Making claims”).

Herbal hit

OVI Hydration is a tea infusion and claims to contain antioxidants from green tea. But the tea extract (made up of green and oolong tea) is only 0.05% of the drink. OVI also contains fruit juice, fructose and honey, which all contribute to two-and-a-half teaspoons of sugar per glass.

But at least it states how much herbs it contains. Ch’i Herbal Rejuvenation Sparkling Refresher Herbal Sugar Free contains an “ancient” herb blend, but the ingredients list doesn’t disclose the quantities of herbs.

The Food Standards Code requires the percentage of characterising ingredients to be stated. We think herbal extracts are a characterising ingredient in Ch’i so the amounts should be listed on the bottle. The manufacturer has a different view.

Added vitamins

Both Mizone Sports Water and Glaceau Vitamin Water have added vitamins. Glaceau also has minerals, such as selenium in the mixed berry flavour and iron in the dragonfruit flavour.

While vitamins perform a number of vital functions in the body, Mrs Stening says people should be encouraged to get their water-soluble vitamins (B and C) from fresh fruit and vegetables. “In excess we excrete what we don’t need, so these drinks are making expensive urine,” she says.

It’s not just vitamins and minerals you’re getting from these products either. Both products contain a sugar hit. Mizone has apple juice and fructose, and Glaceau Vitamin Water both fructose and sucrose. Glaceau is the more sugar-laden with more than five teaspoons in its single-serve 500ml bottle.

Just add water

A cheaper option to these drinks is Vitasport Water Booster. You add one sachet of powder to 750ml of water and you get a vitamin B and C boost, without the extra sugar and kilojoules. But like the other products, any excess will just be excreted in your urine — and the drink is also acidic.

VitalZing Water Drops is another product you add to water. Described as “water flavour enhancers”, you add a few drops to water according to taste. The Water Drops have no added sugar but they’re sweetened with stevia, a natural sweetener. So if you’re trying to wean yourself off sugary drinks you’ll still be creating a preference for sweetness. They’re also acidic, which means they’re bad for your teeth.