The thought of washing down a mouthful of food with a swig of cold water appeals to many people. You may even think it’s necessary for digestion. While water is no doubt essential for many body processes and for good health in general, drinking it with food likely has more negative effects on digestion than benefits.
Importance of Water
Your body is made up of approximately 70 percent water, which is essential for the flow of nutrients and waste into and out of all cells. A great solvent, water is able to dissolve vitamins, minerals, sugars and other nutrients and transport them around your body. Water also conducts electricity, which is essential for carrying electrical messages from the brain to all your tissues via nerves. Traditional advice on water consumption is eight 8-ounce glasses of water daily, although some active women may need to drink up to 75 ounces to replenish fluid loss and stay healthy. However, drinking water or other beverages with meals may compromise digestion.
Digestion of food starts in your mouth with chewing and the release of saliva. Saliva is mostly water, but it also contains enzymes that start to metabolize food and compounds that make it somewhat slippery. Thoroughly chewing your food breaks it down into small pieces and saturates it with saliva, which allows the food to easily slide down your esophagus and into your stomach. Your stomach secretes very acidic juices and some additional enzymes that further metabolize the food. As such, additional water is not needed for healthy digestion. This is evidenced by the fact that indigenous peoples rarely drink beverages with meals and report few, if any, digestive problems. On the other hand, if you have an infection or disease of your salivary glands that leads to “dry mouth,” then sipping water with meals may be necessary.
Diluted Stomach Acid
Perhaps the main detriment to drinking lots of water with meals is the dilution of the hydrochloric acid in the stomach. Hydrochloric acid is the primary ingredient in gastric juice and should have a rating of between 3.0 and 4.0 on the pH scale to be effective at its job, which includes breaking down food, activating enzymes and triggering the absorption of vitamin B-12. Too much water at mealtimes can raise pH levels and make the gastric juice less effective. Poor protein metabolism and reduced B-12 absorption are the most likely results.
The habit of washing food down with water tends to reduce the amount of time spent on chewing. Without water, chewing is needed to reduce the size of the food but also to trigger the release of adequate saliva so the food slides down the esophagus without pain. Drinking water allows you to cheat the process somewhat, which reduces the amount of mechanical and chemical digestion that’s meant to take place in the mouth. Fast eaters tend to drink water at mealtimes because it makes premature swallowing less painful.
Good hydration is important for digestion because it allows adequate secretion of saliva and reduces constipation, especially if you eat lots of fiber. However, drinking water or other beverages such as fresh juice or herbal tea is likely more helpful between meals. Drinking liquids between meals may also help curb your appetite and contribute to weight loss.
- American Dietetic Association Complete Food and Nutrition Guide, 3rd Edition; American Dietetic Association
- Textbook of Nutritional Medicine; Melvyn Werbach and Jeffery Moss
- Advanced Nutrition and Human Metabolism; James L. Groff et al.
Sirah Dubois is currently a PhD student in food science after having completed her master's degree in nutrition at the University of Alberta. She has worked in private practice as a dietitian in Edmonton, Canada and her nutrition-related articles have appeared in The Edmonton Journal newspaper.