Water for Diabetes

How important is it for people with diabetes to stay hydrated? Some evidence shows it’s very important.

A study of 3,600 people from France found that those who drank more than 34 ounces of water a day were less likely to develop high blood sugars (hyperglycemia) than those who drank 16 ounces of water or less.


Subjects were followed for about nine years. Researchers controlled for age, sex, weight, physical activity, and consumption of beer, sugary drinks, and wine.

Why would staying hydrated help control blood sugar? According to an article in The New York Times, being too dry releases a hormone called vasopressin. Vasopressin tells your kidneys to hold onto water and tells the liver release stored blood sugar. It also raises your blood pressure. Extra sugar should be passed out of the body in urine, but if there’s not much water and too much vasopressin in your system, the kidneys don’t make urine.

Not drinking water can lead to overeating and weight gain. According to health writer Phyllis Edgerly, a research report from 2001 found that “In 37% [of Americans], the thirst mechanism is so weak that it is often mistaken for hunger.” Dehydration also slows down the body’s metabolism and is a major cause of fatigue.

How much water do you need?
When you consider that our bodies are roughly 50% (in an elderly person) to 75% (in a newborn baby) water, it makes sense that we need to replace a fair amount each day. Dr. F. Batmanghelidj, MD, writes on his site, “The Water Cure” that, “Through activities of daily living, the average person loses about 3–4 liters (about 10–15 cups) of fluid a day in sweat, urine, exhaled air, and bowel movement. What is lost must be replaced by the fluid we drink and the food we eat. We lose approximately 1–2 liters of water a day just from breathing.”

Ten to 15 cups a day may sound high, but consider that consuming caffeine or alcohol causes even more water loss. Physical activity, hot weather, high altitude, or dry air increase the need for water. So do fevers, diarrhea, high fiber intake, and high blood sugar.

Higher-than-normal blood sugars make blood thicker. Sticky blood can increase insulin resistance by making it hard for glucose to move through the little blood vessels to the cells. Drinking water may help glucose get into cells by making blood less sticky.

Doctors don’t agree on the exact amount needed — it varies from individual to individual and from day to day. You can tell when you need water in several ways.

• Thirst. Normally when your body needs water, it will tell you with thirst. But it doesn’t always, especially as you get older. People with diabetes may get used to being thirsty and not feel it, or feel it as hunger. Other people may feel thirst but ignore it, which can be a big mistake.

James Pendergast of Diabetes Information Network says that if you have diabetes, “you can’t rely on your sense of thirst to keep yourself well hydrated. If you wait until you are thirsty to drink water, you’re waiting too long.”

• Dark urine. Urine should be light colored and in good amounts. Dark urine can mean the body is low on water and is trying to conserve its supply.

• Skin tone. Pinch up some skin between your thumb and index finger, and then let it go. It should snap right back into place. If it goes slower, you are getting dehydrated. Drink some water.

• Common sense. If you’re sweating or exercising or singing or breathing hard, you will be losing water and need to replace it.

You don’t have to get all the water in liquid form. Dietitian Amy Campbell points out that “About 20% of our water intake comes from food, and some foods are mostly water, such as lettuce, watermelon, broccoli, and apples.”

When you are pushing water, you might also want to replace a little salt. Drinking too much water without salt can cause low sodium levels, which are unsafe.

One other point — nothing in this article should be taken as advice to drink bottled water, bottled fruit juice, or sports drinks, unless you’re actually playing sports. Bottled liquids are ridiculously expensive, environmentally destructive, and often have unhealthy additives like sugar. It takes much fossil fuel energy and water just to make the bottle. Get yourself a metal bottle and fill it from the tap. You can add a squeeze of lemon or lime to make it tastier. Hopefully, you’ll get to like it, because it’s definitely good for you.

What should you do to make it through an illness that makes it hard to hold food down? Bookmark DiabetesSelfManagement.com and tune in tomorrow to learn some tips from Scott Coulter, who’s been living with Type 1 diabetes for 22 years.

  • Yeah, the tap could be safe, if it weren’t for the high lead levels in our pipes. And when the water gets contaminated with higher levels of bacteria, the water company doesn’t tell us until days later. But you are just telling people that tap water is always safe! It’s not true.