Water and Gut Health: Why Fibre Needs Fluid

Water is one of the most important things when it comes to gut health—and the health of our whole bodies, for that matter! It can be so easily overlooked when everyone is focusing on eating enough fibre, pre-, pro- and postbiotics, and the latest gut microbiome testing.

But one of the best and easiest things you can do to support your gut is make sure you’re drinking enough water, especially when you’re increasing your fibre intake.

Water and fibre are better together

Fibre can act in different ways in the gut: as a stool-bulking agent or as food for the microbes in our gut. Some fibres contribute to both. Having enough fluid alongside your fibre helps support normal bowel function.

Without enough fluid, stools can become harder and more difficult to pass, leaving us feeling constipated and sluggish. Water also supports digestion and nutrient absorption, so its role goes well beyond keeping us regular.

How your colon keeps things moving

What actually happens in the bowel is that our large intestine, or colon, absorbs and secretes water and electrolytes, continually regulating the hydration of our stool.

Electrolytes are electrically charged minerals, including sodium and chloride. Cells in our gut move these across the gut lining, which helps drive the movement of water. This balance helps keep our stool at a consistency that can move through the bowel comfortably.

When we get sick with a stomach bug, infection can disrupt this balance, causing more water to enter—or less water to be absorbed from—the bowel. This can result in diarrhoea.

Research in mice showed that restricted water intake caused drier stools and slowed transit through the gut, which was expected. But changes in gut microbes and immune cells were also observed—even though the mice did not show significant changes in the blood markers used to assess dehydration.

This was animal research, so we can’t assume the same effects happen in people. But it’s an interesting insight into how water availability might influence the environment inside our gut.

Making sure we’re drinking enough is one practical way to support normal bowel function.

So how much water do we actually need each day?

Well, this varies depending on the amount of activity we’re doing, the climate we live in and our individual circumstances. We even lose water through breathing and through our skin when we aren’t noticeably sweating.

As we get older, our thirst signals can become less reliable. So relying only on feeling thirsty may not always be enough, particularly for older adults. Having regular opportunities to drink can help.

We don’t just get water from drinking water; we also get it from our food. In fact, around 25% of total water intake comes from food in the calculations used for the Australian adult reference values.

With that in mind, these are the Australian and New Zealand Adequate Intake reference values for adults:

Adults	Fluids from drinks	Total water, including food
Women	2.1 L/day	2.8 L/day
Men	2.6 L/day	3.4 L/day

These are reference values, rather than exact requirements for everyone. You may need more in hot weather or when you’re very active. The fluids column includes water and other drinks; it isn’t an amount of plain water to drink on top of everything else.

Does tea and coffee count?

Yes, they do! Tea and coffee count towards your daily fluid intake, although water is a healthy, simple choice to make your main drink.

The water you use to mix your Supplamize blend counts too!

Exercise, sweat and electrolytes: when do you need more?

When we exercise intensely, we can sweat A LOT! Sweat is made up of water and salts, particularly sodium and chloride, and helps our bodies cool down.

The amount we sweat varies between people, how much we’re exercising and the conditions we’re exercising in.

This is where electrolyte drinks can come in. When we’re sweating a lot and losing substantial amounts of fluid and electrolytes, a suitable drink can help replace what we’ve lost. Sodium helps the body retain fluid, while glucose and sodium working together in the gut can support water absorption.

But we don’t necessarily need electrolyte drinks on a daily basis. They can be useful during prolonged or intense exercise, substantial sweating or recovery between sessions; they aren’t automatically needed for every workout.

Five easy ways to drink more water

Here are some practical tips to help you drink regularly and support your gut health!

1. Make it part of your routine. Have a glass first thing in the morning and a drink with your meals.
2. Get to know your bottle and glass. Check how much water your bottle carries and what one cup (250 mL) actually looks like in your usual drinking glass.
3. Keep a log for a week. Measuring your intake for a few days can help you understand your usual habits and spot opportunities to drink more.
4. Always have water close by. Keep a glass on your desk or take your water bottle in the car. Make it easy to remember!
5. Make your daily Supplamize blend one of your glasses of water. It’s one easy drinking cue to build into your routine 😊

References

Moghaddam, H. S., Abkar, L., & Fowler, S. J. (2024). Making waves: From tap to gut—Exploring the impact of drinking water on gut microbiota. Water Research, 267, 122503. doi:10.1016/j.watres.2024.122503

National Health and Medical Research Council. (n.d.). Water. Retrieved from https://www.eatforhealth.gov.au/nutrient-reference-values/nutrients/water

National Health Service. (2023, May 17). Water, drinks and hydration. Retrieved from https://www.nhs.uk/live-well/eat-well/food-guidelines-and-food-labels/water-drinks-nutrition/

National Institute of Diabetes and Digestive and Kidney Diseases. (2018, May). Eating, diet, & nutrition for constipation. Retrieved from https://www.niddk.nih.gov/health-information/digestive-diseases/constipation/eating-diet-nutrition

Negussie, A. B., Dell, A. C., Davis, B. A., & Geibel, J. P. (2022). Colonic fluid and electrolyte transport 2022: An update. Cells, 11(10), 1712. doi:10.3390/cells11101712

Pérez-Castillo, Í. M., Williams, J. A., López-Chicharro, J., Mihic, N., Rueda, R., Bouzamondo, H., & Horswill, C. A. (2024). Compositional aspects of beverages designed to promote hydration before, during, and after exercise: Concepts revisited. Nutrients, 16(1), 17. doi:10.3390/nu16010017

Sato, K., Hara-Chikuma, M., Yasui, M., Inoue, J., & Kim, Y.-G. (2024). Sufficient water intake maintains the gut microbiota and immune homeostasis and promotes pathogen elimination. iScience, 27(6), 109903. doi:10.1016/j.isci.2024.109903