On Nutrition by Ed Blonz

Water Won’t Wash Away Nutrients

DEAR DR. BLONZ: What are your thoughts about drinking water, or another water-based liquid, in the 30 minutes after eating? In a course taught by a naturopath, it was explained that fluids could dilute or wash away digestive enzymes, limiting their efficiency by decreasing contact between the food and our digestive organs. How would this impact the otherwise healthful practices of having soup or a large salad (both mostly water) with a meal? -- S.T., Casa Grande, Arizona

DEAR S.T.: Mostly fiction here. The digestive enzymes’ primary activities do not take place until the food has left the stomach and begun to travel through the small intestines. Water tends to be rapidly absorbed. The “dilution of digestive enzymes” makes little sense, as enzymes attach themselves to specific parts of a specific food component. The issue here is the number of molecules of enzymes versus the number of molecules of their food-component target. Water is not a target for enzymatic action, so it has no major impact on this.

There might be some issue of water consumption and transient bloating, if excessive amounts of water are consumed while the food remains in the stomach. There also might be a problem for those with gastroesophageal reflux, as the extra volume in the stomach might encourage some sloshing up onto the esophagus while the stomach is doing its thing. Then there is the potential issue of aerophagia, the swallowing of air while one eats or drinks, which subsequently leads to belching -- often confused with indigestion.

Water and water-based foods are fine; in fact, they can contribute to satiety and decrease the total amount of calories consumed. A study in the June 2005 issue of Obesity Research looked at overweight women on a calorie-controlled weight-loss program. It was reported that having a soup with low energy-density at the start of a meal led to more weight loss than consuming the same number of calories in the form of a snack food with high energy-density.

An interesting study in the October 2004 Journal of the American Dietetic Association examined the impact of different types of salads. Researchers provided either no salad, a low energy-dense salad (0.33 kcal per gram), or a high energy-dense salad (1.33 kcal per gram) -- the difference coming from the addition of cheese or a rich salad dressing. These salads were served in either a small portion (150 grams) or a large portion (300 grams). After the mandatory salad course, the subjects consumed as much of the main course (pasta) as they desired. Those having the low energy-dense salad as their first course consumed fewer calories during the entire meal. The small serving of salad reduced energy intakes by 7 percent, and a large serving correlated with a mealtime energy reduction of 12 percent. Of interest, those who consumed a small portion of the high-energy dense salad ended up having 8 percent more calories during the meal, and those with the large portion of this salad had 17 percent more calories.

I shift things around a bit. Fresh greens are a part of my daily diet. My dinner strategy is to have set portions of the main course and any side dishes, and I then “fill up” on salad as my final course. Moving salads to the end of the meal has served me well over the years.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.