Does Drinking Water Lower Blood Sugar?

4 minutes read

Usually when people talk about optimizing blood sugar, they focus on what foods to eat. But the impact of hydration – and the types of beverages we drink – is important for managing glucose levels as well.

How hydration affects your blood sugar levels

First and foremost, drinking water doesn’t directly lower blood sugar—no single food or drink has that effect.

With that said, hydration and blood sugar levels are very closely connected. Studies have shown that low water intake and dehydration can lead to higher blood glucose levels [1].

When you are dehydrated, less water makes up your blood volume, but the amount of glucose doesn’t change. his leads to a higher concentration of glucose in your blood, so you will have higher blood glucose readings [2]. High blood sugar levels prompt your kidneys to regulate glucose by excreting excess through urine. This can cause frequent urination, further exacerbating dehydration.

Due to this, drinking water and hydrating beverages is critical to overall health and metabolic health.

Another aspect to consider is how hydration levels can affect continuous glucose monitor (CGM) readings. A CGM uses interstitial fluids to measure your glucose levels. If you are not hydrated enough, the decrease in fluid levels can potentially lead to inaccurate readings. Staying adequately hydrated throughout the day allows you to be certain that your glucose readings are more accurate.

Why what you drink — and when you drink it — matters

Your choice of beverage and the timing of consumption can significantly affect blood sugar levels. Ingredients added to drinks, such as caffeine or artificial sweeteners, or the type of drink itself can change the impact a particular beverage has on your blood sugar. Timing of consumption of certain drinks can influence glucose levels as insulin sensitivity fluctuates throughout the day, with it generally being lower at night [3].

Caffeine

The effect of caffeine on blood sugar levels is complex and can vary from person to person. Some research suggests that ingesting caffeine can reduce insulin sensitivity in the short term, potentially leading to higher blood sugar levels [4, 5].

However, long-term studies show the opposite effect – consuming caffeine can improve glucose metabolism and may reduce the risk of developing insulin resistance and type 2 diabetes [5, 6].

Overall the evidence is not conclusive, and the impact of caffeine can depend on individual factors such as caffeine tolerance and overall diet.

Non-dairy milks

Not all non-dairy milks are created equal when it comes to their impact on blood sugar. For example, oat milk can have a drastically different effect on glucose levels when compared to nut-based milks like almond milk. This difference is due to the high carbohydrate content in grain-based milks, like oat milk or rice milk, which can influence your glucose more significantly by causing large spikes in blood sugar levels.

Artificially sweetened beverages

While artificially sweetened beverages may not directly raise blood glucose levels (because they do not contain sugar), they can impact glucose metabolism in other ways. Research shows artificial sweeteners can cause rises in insulin levels that don’t correspond directly with changes in glucose and may decrease insulin sensitivity.

Despite this, beverages with artificial sweeteners are generally a better choice than sugary sodas, which can cause significant glucose spikes and contribute to weight gain and insulin resistance.

Alcohol

Alcohol consumption can have varying effects on blood sugar, depending on the amount and type of alcohol consumed and individual alcohol metabolism in the liver. When you drink alcohol, you inhibit the liver’s metabolic pathway that creates glucose. If you track your levels with a CGM, you may notice your blood glucose levels are lower than normal after drinking. Your glucose levels typically balance out within a short time frame, however, because alcohol also stimulates glycogenolysis, the breakdown of glycogen into glucose. This process will cause glycogen to be released from the liver and converted to glucose, which will raise your blood sugar levels.

In moderation, alcoholic beverages may have minimal impact on glucose levels [7]. However, alcohol can negatively impact your sleep, which is closely tied to metabolic health. Excessive or long-term consumption of alcoholic beverages can lead to insulin resistance, type 2 diabetes, and liver damage.

How hydration affects satiety

Hydration plays a critical role in regulating satiety, the feeling of being full. Sometimes, feelings of hunger may actually indicate that you are thirsty.

Drinking water before or during a meal can also enhance your feelings of fullness, aiding in weight management and metabolic health. Research indicates that consuming water with meals can increase satiety and reduce overall calorie intake [8]. Choosing water over sugary drinks is vital for preventing blood sugar spikes, which can contribute to a cycle of hunger and overeating.

Key takeaways

While drinking water alone does not lower blood sugar levels, staying hydrated is an essential part of a metabolically healthy diet and can impact glucose management. Choose beverages that aid in hydration, as this can play a significant role in maintaining balanced blood sugar levels.
Consider the impact different beverages can have on your blood sugar. Sugar-sweetened or high glycemic beverages (like soda or oat milk) can cause large glucose spikes.
Other ways to stabilize glucose levels include optimizing the Four Pillars of metabolic health – diet, exercise, stress, and sleep.

References:

Written by: Sarah Jayawardene, MS

Reviewed by: Emily Johnson, MSc RD

Table of Contents

How hydration affects your blood sugar levels
Why what you drink — and when you drink it — matters
How hydration affects satiety
Key takeaways