Energy drinks cause dehydration and sleeplessness, experts say

Students down them to fuel late-night study sessions. Athletes drink them to enhance performance. Bar-goers mix them with vodka to party into the wee hours of the morning. Some people even grab a can to give themselves a boost for a long day at the office.

Energy drinks are becoming increasingly popular with the younger generation, especially for males interested in extreme sports, video games and hip hop. With names like SoBe Adrenaline Rush, Monster Energy, Hype Energy and Everlast, these trendy brews claim to "improve muscle tone," "increase endurance" and "invigorate the mind and body." Hype Energy's marketing materials declare the product helps "partiers stay out, athletes excel, employees get it done and students stay up."

Yet there's no scientific evidence to show that guzzling an energy drink does any of these things. What's more, many experts aren't convinced these drinks are safe. Their high caffeine and sugar content may be dangerous for some people, especially the young and active.

While different brands have similar but not identical formulations, many energy drinks are a concoction of sugar, a hefty dose of caffeine, B vitamins and herbs such as guarana (a source of caffeine) and ginseng. Some, like Red Bull and Red Rain, contain extra ingredients such as taurine (an amino acid which occurs naturally in foods) and gluconolactone (a carbohydrate). According to Red Bull's website, it's the combination of all the ingredients together that result in the product's touted energy lift.

Energy drinks should not be confused with sports drinks, such as Gatorade, which are meant to rehydrate the body. Compared with energy drinks, sports drinks are lower in sugar (with about 15 grams of sugar per 250 millilitres) and they provide the electrolytes sodium and potassium to replace what is lost in sweat.

Energy drinks, on the other hand, are revved-up soft drinks. A single 250 ml (one cup) serving contains anywhere from 25 to 38 grams of sugar (roughly six to nine teaspoons). That's comparable to a similar-sized serving of pop. (Some manufacturers are offering sugar-free versions sweetened with aspartame or sucralose.)

Along with all the sugar, energy drinks deliver plenty of caffeine. Most contain 80 to 100 milligrams of caffeine per 250-millilitre can -- about the same amount that is in a 170-ml cup of coffee and more than twice as much found in a 355-ml can of cola.

New research suggests that downing these sugar- and caffeine-laced energy drinks can lead to weight gain. A small study from Auckland University of Technology in New Zealand found that young women who consumed 250 ml of an energy drink converted more sugar into fat than did women who drank 250 ml of equally sugary, but caffeine-free, lemonade.

Some people, especially children and teenagers, are more sensitive to the effects of caffeine. Even small amounts can cause sleep disturbances, irregular heartbeat, irritability and nervousness in young people. Also, consuming too much caffeine and not enough calcium can undermine bone density. Health Canada advises children aged seven to nine years to consume no more than 62 mg of caffeine per day and 10- to 12-year-olds no more than 85 mg (adults should consume no more than 400 to 450 mg daily).

When energy drinks are consumed in greater quantities than recommended, or when they're used by kids, during sports, or in combination with alcohol. their effects may lead to health problems. The main concern is their potential to cause extreme dehydration, because caffeine acts as a diuretic (causing the body to lose water). Exercise alone can dehydrate a person, so consuming caffeine-packed energy drinks before, during or after sports can worsen dehydration and be dangerous to the heart. As well, the high concentration of sugar in energy drinks slows the body's ability to absorb water.

Mixing energy drinks with alcohol also carries a number of dangers. The stimulant effects of energy drinks can mask how intoxicated you are. Because both caffeine and alcohol are diuretics, dehydration can hinder the body's ability to metabolize alcohol, increasing your blood alcohol level.

Concerns about the safety of energy drinks have led Denmark, Norway and France to ban them. Sweden's food agency advises people not to consume Red Bull with alcohol or as a thirst-quencher.

In Canada, some energy drinks must be regulated as a natural health product, depending on their ingredients and the claims they make. Currently only Red Bull is authorized for sale as a natural health product in Canada. (The safety of other energy drinks has not yet been evaluated.) A can of Red Bull bears a natural health product number and warning statements. The label instructs adults to limit their daily intake to 500 ml (two cans) and warns the product is not to be mixed with alcohol, nor is it recommended for children, pregnant or breastfeeding women, or those sensitive to caffeine. Yet the fact that energy drinks are sold in convenience stores, gas stations, Wal-mart, Costco and some grocery stores means that kids have no problem buying them.

Clearly, energy drinks are not for everyone. If you do use energy drinks, practise the following tips to minimize your risk of dehydration:

Follow label instructions. Do not drink more than is recommended on the label. Most manufacturers state a maximum daily intake of one to two cans (250 to 500 ml).

Pay attention to serving size. Brands like Sobe No Fear and Coca Cola's Full Throttle come in 473-ml cans. Larger cans mean more caffeine, sugar and herbal ingredients.

Do not mix energy drinks with alcohol.

If you engage in heavy exercise, drink plenty of water to rehydrate your body.

Leslie Beck, a Toronto-based dietitian at the Medcan Clinic, is on CTV's Canada AM every Wednesday. Visit her website at lesliebeck.com.

Energy drink lineup

Calories, sugar and caffeine per can of selected energy drinks

*Sugar-free versions are available. NOTE: can sizes vary

SOURCE: MANUFACTURERS