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Dehydration Can Be a Disaster for Gut Health—Here’s How a Gastro Stays Hydrated in the Heat

There’s no gut health without proper hydration—they go hand in hand.

By now, you’ve likely heard us stress the importance of staying well-hydrated far too many times. And while we never want to give “helicopter parent,” hydration has been shown to be a key marker of healthy aging time and time again. (Just saying…!)

In truth, this comes as little surprise, as the human body is made up of nearly 60 percent water. As such, H2O is vital for just about every bodily function: breathing, neurological activity, circulation, you name it. And while fiber usually is the talk of the town when it comes to gut health, proper hydration is equally important for keeping things properly flowing.

We caught up with Sarah Robbins, MD, MSc, FRCPC, a gastroenterologist, gut health expert, and the Founder of Well Sunday, who shared why proper hydration is so important for gut health and the best hydrating foods to eat so your gut stays happy and healthy all (blisteringly-hot) summer long.

Why is hydration so important for gut health?

Let’s break it down. In the simplest of terms, Dr. Robbins shares that hydration is essential for digestive health and function. “It plays an important role in gastrointestinal tract secretions, the digestion and absorption of nutrients, waste elimination, and gut microbiome support,” Dr. Robbins says. According to her, this also means that your body’s fluid balance and energy levels ultimately depend on how well your gut is absorbing water.

What’s more, Dr. Robbins explains that digestion would be nearly impossible without adequate hydration. “Hydration is critical for the formation of saliva, gastric acid, and enzyme secretions. necessary for the digestion and absorption of nutrients,” she says, which makes total sense. Additionally, the gastroenterologist notes that it’s responsible for ensuring waste gets through the gut and kidneys smoothly (pun intended). Plus, it’s one of the best ways to help prevent (and relieve) constipation.

Fluids also help facilitate nutrient absorption and maintain the health of the cells lining the cut. “Fluid inside the gut improves the mixing of food in the stomach and absorption of nutrients in the small intestine. Water mixes with fibers in the gut, facilitating its role as a prebiotic, creating a gel-like substance with soluble fibers and binding to insoluble fibers to eliminate waste,” Dr. Robbins says. “The gut lining serves as a barrier and aids in nutrient absorption while keeping harmful bacteria and substances out of the bloodstream. Proper hydration also provides an optimal environment for the proliferation of a healthy gut microbiome.”

“Fluid inside the gut improves the mixing of food in the stomach and absorption of nutrients in the small intestine. Water mixes with fibers in the gut, facilitating its role as a prebiotic, creating a gel-like substance with soluble fibers and binding to insoluble fibers to eliminate waste,” Dr. Robbins says.

That said, Dr. Robbins caveats that research on the gut is only in its infancy, and more research is needed to conclusively determine the impact of hydration on the gut.

So, what’s the best way to maintain a well-hydrated gut microbiome?

While few things are more thirst-quenching than a big ol’ glass of water, Dr. Robbins notes it’s not the only route to a well-hydrated gut. “Fluid intake through both liquids and foods is important for gut health and overall hydration. Drinking water is the most obvious way to hydrate, but water-rich foods also contribute significantly to daily fluid intake,” she says.

Case in point: Dr. Robbins notes that many fruits and vegetables are composed of over 90 percent water. “Consuming these foods can help maintain hydration while also providing fiber and nutrients,” she says.

Think of hydrating foods as a one-two punch of fluids and necessary nutrients. “Fiber present in many water-rich foods can support gut health by promoting healthy bowel movements and serving as a food source for beneficial gut bacteria,” Dr. Robbins says. Plus, she points out that not all fluids are equally hydrating. (Looking at you alcohol, which can easily have the reverse effect, especially on the gut.)

TL; DR? Dr. Robbins says that the most effective what to harmonize both your gut and your hydration levels includes: plenty of water, plant-based foods with a high water content, and fiber… and fewer sugary foods and/or boozy beverages.

TL; DR? Dr. Robbins says that the most effective what to harmonize both your gut and your hydration levels includes: plenty of water, plant-based foods with a high water content, and fiber… and fewer sugary foods and/or boozy beverages.

8 hydrating foods that are also great for gut health

Dr. Robbins says that gastroenterologists recommend hydrating foods, because they provide both water as well as other essential nutrients (like fiber and antioxidants). “Eating these foods can help maintain hydration and contribute to a balanced, fiber-rich diet that supports overall gut health,” she says. But she stresses that this doesn’t, by any means, replace the need for drinking water. “Drinking water is still necessary, as it’s unlikely you’ll be able to meet your entire hydration needs from food alone,” Dr. Robbins says.

  1. Cucumbers: Composed of about 96 percent water, cucumbers are one of the most hydrating foods available. They also contain a good amount of fiber and vitamin K.
  2. Celery: Celery is approximately 95 percent water. Besides providing hydration, it’s also a good source of fiber and vitamin K.
  3. Watermelon: Watermelon is approximately 92 percent water and it’s packed with vitamins A and C. It also contains lycopene, an antioxidant linked to heart health, sun protection, and possibly cancer prevention.
  4. Strawberries: Like watermelon, strawberries are about 92 percent water. They’re also high in fiber, vitamin C, and antioxidants.
  5. Bell peppers: Bell peppers are about 92 percent water. They’re also rich in vitamin C and fiber.
  6. Oranges: Oranges are about 88 percent water and are high in vitamin C. They also contain fiber and several other important nutrients.
  7. Dark leafy greens: Depending on the type, lettuce contains about 95 percent water. It also contains folate, vitamin C, and vitamin K.
  8. Zucchini: Zucchini is about 95 percent water, and it’s a good source of vitamins A and C, fiber, and potassium.

An RD shares a guide to the most hydrating foods: