I’ve been thinking about this topic for awhile. Actually, since one day in my physiology class last year. We were talking about gastrointestinal motility patterns. And why would that be the one on my mind recently? While we were learning about how fast different meals empty from the stomach I was thinking about something that I had heard about back in my days of reading random things on health and nutrition. Somewhere there emerged an idea that drinking water with meals was detrimental to digestion.
The suggestion was that the water would lower the pH level of the stomach and dilute the digestive enzymes, thus making food harder to digest. According to the internet this could cause indigestion, heartburn, irritability, bloating, lethargy, headaches, insatiable cravings, inability to determine hunger, depression. I’m wondering if it also caused the dust all over my house and those pesky lost socks!
I never could get truly into this way of eating because I quickly found that telling myself that I couldn’t have liquids during meals made me want them that much more! Not to mention there are several foods that are a challenge for me to swallow without liquid.
What we learned in physiology that day was that the rate that liquids empty the stomach is faster than any other component of a meal.
The figure to the right shows that liquid empties from the stomach in about 20 minutes, much faster than the semisolid or solid foods, which take from 60-100 minutes. So, the liquid isn’t going to be in the stomach for long, messing with your stomach pH. Second, the pH of the stomach is LOW, about 0.7 to 3.8 which is very acidic. So acidic that there isn’t much that can change that except food, which only brings it up a small amount.
In my undergrad I did some experiments in chemistry with making an acidic solution less acidic (more basic), and I can tell you without a doubt that water alone is not going to change the acidity of a mixture. The other thing happening in your body is what physiologists call the cephalic and gastric phases of digestion. In the cephalic phase we are thinking about and anticipating eating. As you are preparing your meal and just about to sit down to eat it you are anticipating eating it and this is releasing gastric juices in your stomach. The gastric phase is while we are eating and our body releases more gastric juices.
The summation of all this is that drinking liquids during your meal is not going to lower your stomach acidity. You are still going to make plenty of stomach acid (providing things are working correctly in that area in the first place), and none of the liquid you are going to normally drink is going to change the pH level of that stomach acid.
So if you want feel free to enjoy your beverage with your meal again!
Rhoades and Bell, 2013, Medical Physiology: Principles for Clinical Medicine, fourth edition, (pgs 494-495, 509)