Dehydrating Foods: Could What You Eat And Drink Dehydrate You?

05/31/2013 08:15 am ET | Updated May 31, 2013
  • Sarah Klein Senior Editor, Health & Fitness; Certified Personal Trainer
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When the mercury rises, it's natural to feel a little parched. But with sky-high temps, harmless thirst can in some instances become a more serious heat-related illness like heat exhaustion or heatstroke.

Aside from your usual water intake, a number of foods that are loaded with water can help keep you safely hydrated this season. But what about the foods that do damage to your hydration equation?

A common myth is that a single cup of coffee or tea is dehydrating. Luckily for iced coffee fans, that's not enough to cause problems, says Monica Reinagel, MS, LDN, CNS. Both coffee and tea are, unsurprisingly, also high in water. And while the caffeine in your mug is dehydrating, the water makes up for it and more, ultimately leaving you more hydrated in the end. Even soda, which we don't recommend you drink for hydration (or otherwise!), doesn't have enough caffeine to wring you dry.

Of course, if you're really overdoing it on the caffeine, ingesting upwards of 500 to 600 milligrams a day, according to the Mayo Clinic, it is still possible to become dehydrated from your java habit. But hopefully you're not downing five cups of coffee a day.

Caffeine overconsumption aside, there are some foods and drinks that can contribute to dehydration, even if you're eating sensible quantities. It's not that you need to avoid these picks in the throes of the next big heat wave, says Reinagel, but it is a good idea to up your fluid intake if your diet is high in the following.

Alcohol
That summer sangria might be refreshing, but it's a natural diuretic. Alcohol causes cells to shrink, which squeezes extra water out, giving drinkers that urge to hit the restroom, and fast. All those trips to the loo deplete your body's natural water stores, which is why you might wake up with a pounding headache the morning after a big night out, says Reinagel. And if you're drinking outside on a hot summer day, there's even more reason to up your H2O intake, she says. "You could get behind in the dehydration game, with the effects of alcohol and the more profound cause of dehydration: sweating."

And although your adult beverage of choice is technically a liquid, unlike coffee and tea, the fluids in alcoholic drinks don't compensate for their dehydrating effects, says Reinagel, especially if you're having something particularly boozy, like a martini, she says.

Protein
A number of people have turned to higher-protein diets recently, says Reinagel. But whether they're looking to up muscle mass or curb hunger, a little-known side effect of going protein-heavy is that you may become dehydrated, she says. The body has to use more water to flush out the naturally-occurring nitrogen in protein, which results in more trips to the bathroom, she says. It's not that high-protein diets are too be avoided; just consider upping your fluid intake simultaneously, she says.

Herbal Supplements
A number of herbs and supplements have long been used as folk remedies for bloating, thanks to their urine-increasing properties, including parsley, celery seed, dandelion and watercress.

In a 2002 study, researchers found that rats given a parsley seed extract drink excreted a greater volume of urine than when they drank plain water. And dandelion extract showed "promise" as a diuretic in humans according to a 2009 study.

Because of their ability to increase urine production, all of the above have been used medicinally to treat conditions like urinary tract infections, kidney stones and bloating, according to WebMD, both as foods and in supplement form.

While they may indeed help reduce water retention if you're feeling bloated, if you're not experiencing bloat you could run the risk of depleting your water stores, says Reinagel.

However, you'd really have to overdo it, says Mitzi Dulan, RD, CSSD. Even though "no one eats parsley in excess," she says, "it's important to look at the volume [you're ingesting] and find out if there's a toxic level and be aware of that," especially when taking supplements that haven't been studied extensively, she says.

Asparagus
Well-known for altering the odor of urine, asparagus likely also produces more of it, thanks to an amino acid called asparagine, which operates as a diuretic, according to EatingWell. It's been thought to help UTIs and other painful urinary tract conditions, according to WebMD. However, says Reinagel, there's virtually no risk of becoming dehydrated from eating asparagus alone, since vegetables are naturally high in water. "When you have a diet high in fruits and vegetables, you're going to end up urinating more because those foods are high in water," she says. That doesn't mean you're at risk.

What do you think? Tell us in the comments below how you stay safely hydrated in the heat.

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