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  • Writer's pictureTimothy P. Smith MS, RD, LDN

Water & Health: A Brief Overview

Water is an essential element of life, constituting about 60-70% of the human body. It serves as a fundamental substrate for metabolism, and plays a crucial role in maintaining various physiological functions. Adequate water consumption is paramount for human health, nutrition, and metabolism, impacting overall well-being and optimizing bodily processes. As a licensed & registered dietitian, I feel confident that "consuming adequate water" is the area where people stand to gain the most, with the least amount of effort/planning.

This very brief overview will explore the importance of water intake and its significant influence on human nutrition & metabolism, backed by several reputable scientific sources.

Hydration and Physical Performance

Staying adequately hydrated is vital for optimal physical performance. Dehydration can lead to reduced endurance, impaired strength, and decreased cognitive function during exercise (Popkin, D'Anci, & Rosenberg, 2010). Ensuring proper water intake before, during, and after physical activities helps maintain body temperature, lubricate joints, and transport nutrients to cells.

Weight Management

Water consumption is linked to weight management, making it an indispensable tool for those seeking to achieve and maintain a healthy body weight. Drinking water before meals can promote a feeling of fullness, leading to reduced calorie intake (Stookey, Constant, Gardner, & Popkin, 2007). Furthermore, water intake can increase the body's energy expenditure, positively affecting metabolism (Boschmann et al., 2003).

Digestion and Nutrient Absorption

Water is crucial for the proper digestion and absorption of nutrients. It aids in breaking down food in the stomach and facilitating nutrient absorption in the small intestine (Serrano et al., 2019). Insufficient water intake can lead to constipation and hinder the absorption of essential vitamins and minerals, impacting overall nutrition.

Cognitive Function and Mental Health

Proper hydration is closely linked to cognitive function and mental health. Dehydration can result in impaired concentration, memory, and mood (Benton & Young, 2015). Studies have shown that adequate water intake positively influences brain structure and function, promoting mental alertness and emotional well-being (Ganio et al., 2011).

Regulation of Body Temperature

Water serves as a coolant for the body, helping to regulate body temperature through sweating. During hot weather or physical exertion, sweating is essential for dissipating heat and preventing heat-related illnesses (Shirreffs, 2003). Sufficient water consumption is vital to replace lost fluids and maintain a stable body temperature.

As we can see, water consumption is a fundamental pillar of human health, nutrition, and metabolism. Adequate hydration supports physical performance, aids in weight management, facilitates nutrient absorption, enhances cognitive function, and regulates body temperature.

On the other hand, neglecting water intake can lead to adverse health effects and impair overall well-being. It is crucial to prioritize drinking enough water daily to ensure optimal functioning of the human body. As a dietitian, embracing water as a vital component of a healthy lifestyle is a simple, yet powerful step towards promoting lifelong health and well-being.

TL;DR: Drink at least 64 oz of water each day unless your MD/condition indicates otherwise (ESRD, CHF, AKD, currently on dialysis, etc.)

Until Next Time,

Tim Smith MS, RD, LDN




  1. Popkin, B. M., D'Anci, K. E., & Rosenberg, I. H. (2010). Water, hydration, and health. Nutrition Reviews, 68(8), 439-458.

  2. Stookey, J. D., Constant, F., Gardner, C. D., & Popkin, B. M. (2007). Replacing sweetened caloric beverages with drinking water is associated with lower energy intake. Obesity, 15(12), 3013-3022.

  3. Boschmann, M., Steiniger, J., Hille, U., Tank, J., Adams, F., Sharma, A. M., ... & Jordan, J. (2003). Water-induced thermogenesis. The Journal of Clinical Endocrinology & Metabolism, 88(12), 6015-6019.

  4. Serrano, J. C., Zanini, A. C., Dario, M. F., De-Oliveira, L. D., Campos, A. L., & Vannucchi, H. (2019). Importance of water in macronutrient digestion and absorption. Nutricion Hospitalaria, 36(1), 219-226.

  5. Benton, D., & Young, H. A. (2015). Do small differences in hydration status affect mood and mental performance? Nutrition Reviews, 73(Suppl 2), 83-96.

  6. Ganio, M. S., Armstrong, L. E., Casa, D. J., McDermott, B. P., Lee, E. C., Yamamoto, L. M., ... & Lieberman, H. R. (2011). Mild dehydration impairs cognitive performance and mood of men. The British Journal of Nutrition, 106(10), 1535-1543.

  7. Shirreffs, S. M. (2003). Markers of hydration status. European Journal of Clinical Nutrition, 57(Suppl 2), S6-S9.

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