Drinking sufficient water is important for overall health, but it has also been suggested that increasing water intake can help lower blood sugar levels. Here we explore the evidence behind this claim.
The link between dehydration and blood sugar
When the body is dehydrated, it releases hormones that cause the kidneys to hold on to water. One of these is vasopressin, which also signals the liver to produce more blood sugar. This is because the body thinks it needs extra energy when water levels are low. So becoming dehydrated can cause a temporary rise in blood sugar levels.
Some research has found that people with diabetes tend to have higher blood sugar levels when dehydrated compared to when they are well hydrated. One study gave people with type 2 diabetes either a hydrating solution or placebo and found drinking the hydrating solution lowered their blood sugar over a 24 hour period.
These findings suggest keeping well hydrated could help avoid unnecessary rises in blood sugar. However, the effects are mostly relevant for people already at risk of dehydration or with diabetes.
Does increasing water intake lower blood sugar in the long term?
A few studies have looked at whether increased water consumption over weeks or months can lower blood sugar levels:
- One study asked people with type 2 diabetes to drink at least 34 ounces (1 liter) of water daily. After 12 weeks, their fasting blood sugar levels had dropped.
- Another study had people with prediabetes drink 17 ounces (0.5 liters) of water with each meal. After 12 weeks their blood sugar levels had decreased.
- Some other small studies found increased water intake lowered blood sugar markers like HbA1c over 2-3 months.
However, more rigorous large studies are needed to confirm this effect. And it’s not clear if the amount of water consumed makes a difference. One study found no change in blood sugar with 48–64 ounces (1.4–1.9 liters) of water daily over 12 months.
Overall the evidence is currently limited for general blood sugar control in the longer term. The effects also tend to be small and most relevant for those with, or at risk of developing, diabetes.
How could water help lower blood sugar?
Researchers have suggested a few potential ways increased water intake may lower blood sugar, including:
- Preventing dehydration. As mentioned, staying well hydrated prevents rises in blood sugar in response to dehydration.
- Supporting kidney function. The kidneys play an important role in regulating blood sugar. Adequate hydration helps kidneys function optimally.
- Promoting satiety. Some research indicates drinking water before meals promotes feelings of fullness. This may prevent overeating and subsequent spikes in blood sugar.
- Aiding metabolism. Being well hydrated may improve glucose and fat metabolism efficiency.
- Diluting the blood. Drinking adequate water dilutes the concentration of glucose in the bloodstream.
However, not all studies back these proposed mechanisms. More research is still needed to uncover the exact effects of water on blood sugar control.
Tips for increasing water intake
For most healthy adults, doctors recommend drinking around 7-8 cups (56–64 ounces or 1.6–1.9 liters) of water daily. Here are some tips for getting enough:
- Carry a water bottle to prompt you to drink throughout the day.
- Choose water over sugary drinks that can negatively impact blood sugar.
- Set reminders to drink water at regular intervals.
- Add fruit slices or herbs to add flavor if you don’t enjoy plain water.
- Drink a glass of water before meals.
- Consume water-rich foods like fruits and veggies which also provide nutrients.
- Choose water over diuretics like coffee and alcohol that can lead to dehydration.
Should you drink more water to lower blood sugar?
Research into water intake and blood sugar is still emerging. There may be some benefit for people with diabetes or prediabetes. However, results tend to be modest.
There are also some risks to overdoing water consumption. Drinking more than about 1 liter per hour can cause dangerous water intoxication. And increased water intake could potentially impact electrolyte balances. Most people are better off focusing on general health guidelines of 7-8 cups of fluid daily.
Nonetheless, staying well hydrated is important for everyone. If you find drinking more water helps lower or stabilize your blood sugar levels, it can be one part of your overall diabetes management strategy. But always discuss any major diet changes with your healthcare provider.
The bottom line
Here is a quick summary of the evidence on whether drinking water lowers blood sugar:
- Dehydration can temporarily increase blood sugar levels.
- Drinking adequate water prevents dehydration and helps blood sugar stabilize.
- Some research shows increased water intake may lower blood sugar over weeks/months.
- Results tend to be small and most relevant for people with diabetes.
- Proposed mechanisms include aiding hydration, kidney function, satiety and metabolism.
- Aim for 7-8 cups of fluids daily as a healthy goal.
- Discuss any dramatic diet changes with your doctor.
Overall, staying well hydrated is beneficial for blood sugar control and overall health. But dramatic increases beyond recommended intakes provide little additional benefit for most people.
Frequently asked questions
Does drinking water help regulate blood sugar?
Drinking enough water can help avoid dehydration-related spikes in blood sugar. Some studies also indicate increased water intake may improve long-term blood sugar regulation, especially for people with diabetes. However, benefits tend to be modest.
How much water should people with diabetes drink?
There are no specific water intake recommendations for people with diabetes. The general recommendation is 7-8 cups of fluid daily for women and 8-12 cups for men. People on dialysis or with kidney problems may need to restrict fluids.
When should you drink water to lower blood sugar?
Drinking water regularly throughout the day prevents dehydration and related blood sugar rises. Some research also indicates drinking water before meals helps moderate blood sugar spikes after eating.
Does lemon water help control blood sugar?
Some research indicates lemon juice may modestly impact blood sugar levels due to its flavonoids and vitamin C. However, lemon alone in water is unlikely to have any significant effect. The water and hydration benefits are far more important.
Can drinking too much water lower blood sugar too much?
There is little evidence that drinking more water than the recommended daily amount provides additional blood sugar benefits. In fact, drinking excessive amounts of water can dangerously dilute blood sodium levels.
Staying well hydrated by drinking fluids like water as part of a balanced diet is beneficial for blood sugar control and overall health. It helps avoid dehydration, allows kidneys to function properly, and may support metabolic health. However, research does not support excessive water consumption beyond recommended intakes as an effective way to lower blood glucose.