How much water do you need to drink to control blood sugar?

Hydration is a key element in diabetes control, yet the most neglected, says Dr V Mohan, Chairman, Diabetes Specialities Centre, Chennai.

Even mild dehydration can cause significant increases in blood sugar, damaging the body over time (File Image)

When we talk about treating and managing diabetes, we discuss many important things like diet, exercise, sleep, medicines and follow-ups with doctors. But we neglect mentioning the need to drink water and maintain fluid balance. Even mild dehydration can cause significant increases in blood sugar, damaging the body over time.

In fact, water consumption may not be enough for people with diabetes. They should have fluids containing electrolytes as well as an optimal concentration of glucose to facilitate absorption.

Why is dehydration risky for those with diabetes ?

Once the system is dehydrated, the circulating blood glucose becomes more concentrated, resulting in a sugar spike. The kidneys then work overtime to produce more urine to filter the blood. Uncontrolled diabetes results in excessive urination, thirst and worsens dehydration. This can predispose one to diabetic ketosis, a condition when the body doesn’t produce enough insulin to allow blood sugar into your cells for use as energy.

The liver then breaks down fat for fuel, which causes a buildup of acids that can even lead to coma. In fact, one of the first treatments given to a patient of diabetic ketoacidosis and coma is to rapidly infuse fluids into their body. The insulin is administered only after they have been rehydrated.

There is an antidiuretic hormone called arginine vasopressin, or AVP, which plays a key role in maintaining the fluid and electrolyte (salt balance) in the body. Reduced water intake impacts its functioning. Another mechanism by which the body prevents dehydration and keeps salt and water balance through the kidneys is by controlling the volume and composition of the urine. If the kidney is unable to regulate the balance of water and salts, this can lead to fluid and electrolyte abnormalities.

What are symptoms of dehydration among people with diabetes?

The most common symptoms are excessive thirst and dry mouth. In more severe cases, the skin loses elasticity. Accompanying symptoms include headache, dry eyes, dry skin, dark yellow urine, dizziness, general weakness and exhaustion. Sometimes the symptoms of dehydration do not become obvious until the body goes into crisis mode. The pulse then becomes rapid and thready and it can lead to confusion and lethargy.

Can some diabetes drugs result in dehydration?

Recently, the use of drugs like SGLT2 inhibitors lead to excretion of glucose through the urine. That’s why people on such drugs need to increase their water intake by at least half to one litre per day to remain hydrated. Metformin reduces appetite, which in turn decreases water intake and water absorption from solid foods.

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Normally a person with diabetes should consume at least 2 ½ litres of water per day and if on SGLT2 drugs, even up to 3 litres per day. There are however some precautions and contraindications. For example, if a person with diabetes has heart or kidney failure, they may be advised by their doctor to cut down on both water and salt intake.

What are some simple dos and don’ts?

• One should monitor one’s blood glucose level regularly and match readings with fluid intake.
• People with diabetes should not exercise outdoors in the peak of summer.
• Restrict consumption of alcohol, caffeine and sugar sweetened beverages.
• Instead of drinking fruit juices or sweetened drinks, it is always better to drink zero-calorie water. So always carry a bottle.