Can I drink tea and coffee instead of water? Unpacking Hydration Myths

October 13, 2025 •

4 min read

Despite our bodies being roughly 60% water, many people question: Can I drink tea and coffee instead of water? The answer involves understanding both the hydrating and limiting factors of these popular beverages, and why relying solely on them may compromise optimal health.

Quick Summary

Replacing water with tea and coffee is not recommended as a primary hydration strategy. While they contribute fluid, caffeine's mild diuretic effect and potential side effects make plain water the superior choice for optimal body function and health.

Key Points

Moderate intake is hydrating, but not a replacement: While low to moderate consumption of caffeinated drinks contributes to fluid intake, it does not offer the same holistic benefits as water.
Excessive caffeine has negative side effects: High consumption can lead to anxiety, sleep disruption, increased heart rate, and digestive issues, negatively impacting overall health.
Water is calorie-free and pure: Plain water is the ideal hydrating beverage with no sugar, fat, or calories, making it essential for core bodily functions and weight management.
Nutrient absorption can be hindered: Compounds in tea and coffee can interfere with the absorption of important minerals like iron and calcium.
Balance is key: The best approach is to make water your primary fluid source while enjoying tea and coffee in moderation as part of a varied diet.
Consider herbal teas and infused water: For flavorful, caffeine-free alternatives, herbal teas or water infused with fruits and herbs are excellent hydrating choices.

The Hydration Myth: Do Caffeinated Drinks Count?

It's a long-standing myth that any caffeinated beverage will immediately lead to dehydration. The truth is more nuanced. Both coffee and tea are made primarily with water, and moderate consumption does contribute to your overall daily fluid intake. For individuals who regularly consume caffeinated drinks, the body develops a tolerance to caffeine's mild diuretic effect, meaning it doesn't cause a significant net fluid loss. However, this is not a green light to completely replace water. The quality of hydration from plain water, which contains no extra compounds, sugar, or calories, is superior.

The Fine Print on Caffeinated Hydration

Diuretic Effect is Mild: For regular drinkers, the diuretic effect of moderate amounts of caffeine (up to 400 mg, or 4 cups of brewed coffee) is not strong enough to counteract the fluid provided by the beverage itself.
Varies by Individual: The impact can be more pronounced for those who rarely consume caffeine, as their bodies have not built the same tolerance.
Not All Coffee is Equal: A simple black coffee offers more direct hydration than a sugary, milky latte, which introduces additional ingredients that alter the overall nutritional impact.

The Downside of Exclusive Tea and Coffee Consumption

While a balanced intake can be fine, relying exclusively on tea and coffee for hydration introduces several potential health risks that plain water does not. These risks stem primarily from the high caffeine content and other compounds present in these beverages.

Health Risks of Excessive Intake

Anxiety and Insomnia: High doses of caffeine are a central nervous system stimulant that can lead to increased anxiety, nervousness, restlessness, and significant disruption of sleep patterns.
Digestive Issues: Drinking large quantities of coffee or tea, especially on an empty stomach, can stimulate excess stomach acid production, leading to heartburn, indigestion, and potentially aggravating conditions like gastritis.
Nutrient Absorption Interference: Compounds in tea and coffee, such as tannins, can inhibit the absorption of key minerals like iron and calcium. Long-term, this can lead to nutrient deficiencies if not mitigated by a balanced diet.
Cardiovascular Impacts: Excessive caffeine can cause a rapid heart rate and mild increases in blood pressure. Individuals with pre-existing heart conditions should be especially cautious.
Caffeine Dependence and Withdrawal: Relying on caffeine for energy can lead to physical dependence. Suddenly stopping can trigger withdrawal symptoms like headaches, fatigue, and irritability.

Water vs. Caffeinated Beverages: A Comparison

To highlight why water is the optimal choice for primary hydration, here is a comparison table outlining the key differences between plain water and typical tea/coffee.


Feature	Plain Water	Coffee / Tea
Hydration Efficacy	Gold standard; directly hydrates every cell.	Contains water but may be offset by mild diuretic effect and other compounds.
Nutrient Content	Contains essential natural minerals.	Contains antioxidants and other plant compounds; can inhibit mineral absorption.
Calorie Content	Zero calories.	Zero calories (plain), but can be high with added milk, sugar, or syrups.
Caffeine Content	Zero caffeine.	Contains a stimulant (caffeine) that can impact sleep and anxiety.
Effect on Digestion	Aids digestion, flushes toxins, and balances pH levels.	Can increase stomach acid, potentially causing indigestion or heartburn.

The Unique Benefits of Plain Water

While tea and coffee offer some potential health benefits due to antioxidants, they cannot replicate the simple yet vital functions of water. For a healthy body, plain water remains non-negotiable.

Why Water is Best

Optimal Organ Function: Water is critical for every organ, especially the kidneys, as it helps flush out toxins and waste products.
Temperature Regulation: It helps regulate body temperature, particularly important during physical activity or in hot weather.
Joint and Muscle Health: As a lubricant for joints and muscles, water helps prevent cramping and keeps the body moving smoothly.
Cognitive Function: Staying well-hydrated is essential for brain health, increasing mental clarity, focus, and energy levels.
Weight Management: With no calories, water can help you feel full, making it a valuable tool in weight-loss plans.

Balancing Your Fluid Intake

For most healthy adults, the key is balance and moderation. You don't have to eliminate tea or coffee entirely, but you must ensure water is your primary source of hydration. Aim to meet the recommended daily intake for plain water—approximately 15.5 cups for men and 11.5 cups for women, though a portion comes from food.

Practical Steps for Better Hydration

Infuse Your Water: Add slices of lemon, cucumber, berries, or mint to add flavour without extra sugar.
Create a Routine: Drink a glass of water first thing in the morning and before each meal. This helps kickstart your metabolism and hydration.
Track Your Intake: Use a reusable bottle and track your daily progress. Some bottles have markers to help you monitor your intake.
Eat Your Water: Incorporate high-water-content foods like watermelon, cucumbers, and lettuce into your diet.
Alternate Your Drinks: For every cup of coffee or tea, follow it with a glass of water.

Conclusion: Water Reigns Supreme

While tea and coffee can be part of a healthy diet, they are no substitute for plain water. The mild diuretic effect of caffeine and the potential for negative side effects from excessive intake highlight why water must remain the foundation of your hydration strategy. For optimal health and wellness, it is crucial to prioritize plain water while enjoying your favourite caffeinated beverages in moderation. Balancing your fluid intake this way ensures your body receives the pure, consistent hydration it needs to function at its best.

Here is a useful resource for more information on daily water intake guidelines: Mayo Clinic - Water: How much should you drink every day?

Frequently Asked Questions

For individuals who regularly consume coffee in moderation (around 4 cups or less daily), the mild diuretic effect is not enough to cause net dehydration. The water content in the coffee itself outweighs the fluid loss.

For most healthy adults, a daily intake of up to 400 milligrams of caffeine is considered safe. This is roughly the amount found in four 8-ounce cups of brewed coffee.

Yes, caffeinated beverages do contribute to your daily fluid intake. However, they should not be your primary source of hydration due to the potential side effects of excessive caffeine.

Besides water, good hydrating options include herbal teas, milk, fruit-infused water, soup broths, and high-water-content foods like fruits and vegetables.

Relying exclusively on tea or coffee can lead to an array of negative health effects associated with high caffeine intake, including anxiety, sleep problems, increased heart rate, digestive issues, and nutrient absorption difficulties.

Drinking coffee on an empty stomach can increase stomach acidity, which may cause indigestion, heartburn, and irritate the stomach lining. Drinking a glass of water first is often recommended to help balance pH levels.

Adding milk and sugar makes coffee or tea a less-than-ideal hydration source. These additions contribute extra calories and sugar, which can lead to weight gain and inflammation, making plain water a much healthier choice.

Plain water has numerous benefits, including being calorie-free, flushing toxins from the body, aiding in temperature and blood pressure regulation, protecting organs, and enhancing mental and physical capacity.