HYDRATION FACTS

Summary points, conclusions and excerpts:

• Water is an essential nutrient because it is required in amounts that exceed the body’s ability to produce it. Even without perspiration (sensible losses) the normal daily turnover of water is approximately 4% of total body weight in adults and 15% of total body weight in infants.
• New research indicates that fluid consumption in general and water consumption in particular can have an effect on the risk of urinary stone disease; cancers of the breast and colon, and urinary tract; childhood and adolescent obesity; mitral valve prolapse; salivary gland function; and overall health in the elderly.
• The Nationwide Food Consumption Surveys indicate that a portion of the population may be chronically mildly dehydrated.
• Dehydration of as little as 2% loss of body weight results in impaired physiological and performance responses. Early signs of dehydration include headache, fatigue, loss of appetite, flushed shin, heat intolerance, light-headedness, dry mouth and eyes, burning sensation in the stomach, and dark urine with a strong odor.
• Several studies have discovered a direct correlation between the quantity of fluid consumed and the incidence of certain cancers (47-50). In Hawaii, Wilkens et al (50) showed that total fluid intake, and intake of tap water in particular, had a strong inverse dose-relationship to risk of lower urinary tract cancer (bladder, renal pelvis, ureter) among women. Similar findings have been made regarding colon and breast cancer. In a population-based control study of the association between food groupings and colon cancer n Seattle, WA (48), researchers identified a strong inverse dose-relationship between water intake, measured as glasses of water consumed per day, and risk of colon cancer among women. Women who drank more than 5 glasses of water a day had a 45% decreased risk of colon cancer vs those who consumed 2 or fewer glasses per day. Stookey and colleagues (49) announced results of their hospital-based, case-control pilot study of the protective effects of drinking water on breast cancer risk. Water was strongly, inversely, and significantly associated with breast cancer risk. Overall, the risk for developing breast cancer was reduced by 79% among water drinkers when adjusted for age; height; exercise; family exposure; use of hormone replacement therapy; endogenous estrogen exposure; use of oral contraceptives or birth control pill; and tea, coffee, and alcohol consumption. When stratified for pre- and postmenopausal stage, risks were reduced by 33% for premenopausal women and 79% for post menopausal women.

Summary conclusion:

• A high fluid intake is associated with a decreased risk of bladder cancer in men.

Summary points, conclusions and excerpts:

• The clearest and most consistent association with fatal coronary heart disease was found with water intake.
• We have found a strong negative multivariate association between the intake of water and fatal coronary heart disease and, in contrast, a positive association between intake of fluids other than water and risk.
• As fluid intake increases the incidence of fatal coronary heart disease decreases. Moreover, the greater the consumption of beverages other than water, the greater the risk of fatal coronary heart disease.

Excerpt:

• In an update article based on the clinical research conducted by Dr. Chan J., et al, “Water, other fluids and fatal coronary heart disease; The Adventist Health Study published in the American Journal of Epidemiology 2002, May 1; 155:827-33, Dr. Joel M. Gore, MD concluded with this comment: “This provocative report suggests potential associations between high water intake and lower risk for fatal CHD (Coronary Heart Disease) and between high intake of nonwater fluids and higher risk.”

Exceprt:

• • In a review article published by Men’s Fitness of the study conducted by Dr. Chan J., et al, “Water, other fluids and fatal coronary heart disease: The Adventist Health Study published in the American Journal of Epidemiology 2002, May 1; 155:827-33, the magazine article reports the conclusions as such: “The report concludes that proper hydration could save “tens of thousands of lives each year” with minimal cost or effort. If the study results are replicable, “this would be the cheapest and simplest method of preventing coronary heart disease imaginable,” says Gary Fraser, M.D. cardiologist at the LLU Heart Insititute. (One of the above referenced study participants and authors)

Summary points, conclusions and excerpts:

• The increase in energy expenditure with water was diminished with systemic B-adrenoreceptor blockade. Thus, drinking 2 liters of water per day would augment energy expenditure by approximately 400 kJ. Therefore, the thermogenic effect of water should be considered when estimating energy expenditure, particularly during weight loss programs.
• One important implication of our study is that the effect of water on energy expenditure and fuel utilization should be recognized as a powerful confounding factor in metabolic studies. Indeed, water drinking-induced thermogenesis is an important and unrecognized component of daily energy expenditure. If confirmed in other studies, this cost-free intervention may be a useful adjunctive treatment in overweight and obese individuals to attain an increase in energy expenditure.
• This study found a strong correlation between drinking water and enhancing energy expenditure, or an increased rate of calorie burning.

Reviewers Conclusions:

• Simple maternal hydration appears to increase amniotic fluid volume and may be beneficial in the management of oligohydramnios and prevention of oligohydramnios (too little amniotic fluid) during labour or prior to external cephalic version.
• Maintaining ample hydration prior to labor and delivery may decrease risks and complications associated with too little amniotic fluid, especially in post-term deliveries

Summary observations, conclusions and excerpts:

• There are an abundance of reasons to recommend water as an important beverage in the diet. Considering the international epidemic of obesity, water presents a non-caloric beverage that not only re-hydrates, but can also replace calorie-dense nutrient –poor beverages such as soda and fruit-ades Studies indicate that successful dieters in both adult and child populations drink water to take the edge off hunger (6,7). Water induced thermogenesis is currently an area under investigation as a means of increasing caloric expenditure (8). Plasma pollutants (organochlorines) are liberated into the blood stream during weight-loss through the process of fat cell lipolysis (9). Liberal intakes of fluids, preferably non-caloric fluids such as water, may allow for a rapid fluid turnover in order to quickly excrete these toxins from the body.
• Conclusion: Further research investigating the benefits of all fluids, and water in particular, as beverages to meet hydration and health needs will help clarify the controversies over how much water we should drink every day. Health practitioners must further work to assist patients with designing practical fluid intake strategies to ensure adequate hydration.

Abstract and Excerpts:

• Dehydration not only reduces athletic performance, but also places athletes at risk of health problems and even death. For athletes, monitoring hydration has significant value in maximizing performance during training and competition. It also offers medical personnel the opportunity to reduce health risks in situations where athletes engage in intentional weight loss. Simple non-invasive techniques, including weight monitoring and urine tests, can provide useful information. Bioimpedance methods tend to be easy to use and fairly inexpensive, but generally lack the precision and accuracy necessary for hydration monitoring. Blood tests appear to be the most accurate monitoring method, but are impractical because of cost and invasiveness. Although future research is needed to determine which hydration tests are the most accurate, we encourage sports teams to develop and implement hydration monitoring protocols based on the currently available methods. Medical personnel can use this information to maximize their team’s athletic performance and minimize heat-and dehydration-related health risks to athletes.
• Criteria for Hydration: Water is the largest component of body mass, accounting for 50-7-% of body weight.(11) Given that body water is exclusively contained within the fat-free mass compartment (fat mass is anhydrous), the percentage of body water typically accounts for approximately 60-70% of bodyweight in males and 50-55% in females. On a cellular level of body composition analysis, body waer can be partitioned between intracellular and extracellular compartments.(12) Approximately two-thirds of water resides in the intracellular compartment and one-third resides in the extracelluar compartment.
• When it comes to sports performance, water is the single most important and effective energy-enhancing aid.

Excerpts:

• Drinking only half of the recommended eight glasses of water a day may result in mild dehydration, a small study of college students has found. The preliminary study may add credence to the notion that most people would do well to gulp down at least 8-ounce glasses of water each day, lead researcher Dr. Wayne Askew of the University of Utah in Salt Lake City told Reuters health. The findings were presented last week at the annual Experimental Biology meeting in San Diego, California.
• Water makes up 70 percent of solid body tissue and helps regulate body temperature, carries nutrients and oxygen to cells, removes waste, cushions joints and protects organs and tissues. Lack of adequate water intake leads to headaches, grogginess and dry, itchy skin. Severe dehydration affects blood pressure, circulation, digestion kidney function and nearly all body processes.

Exerpts:

• Dehydration causes many common health complaints, such as headaches, mental fogginess, lethargy, anxiety, muscle fatigue and chronic diseases. Headaches occur when inadequate fluid consumption constrict and dilate blood vessels, creating a spasm in the head and causing pain.
• Poor hydration also causes unclear thinking. A study published by the Archives of Environmental Health signified that mild dehydration caused decreased visual ability, short-term memory and difficulty solving addition and subtraction problems.
• New studies show drinking water may also buffer diseases, such as asthma, heart problems and cancer. Water can positively influence respiratory problems. A study at the University of Buffalo found asthmatic individuals have worse lung function when dehydrated and are more likely to suffer attacks.
• Heart health is also improved by drinking water. Dehydration can decrease blood volume, force the heart to pump harder and increase the risk of heart attack. Mitral valve prolapse syndrome (MVPS) is a cardiac condition that occurs when the mitral value (which separates the top of the heart from the bottom) doesn’t close properly, causing a back flow of blood. In a study of MVPS, at the University of Arizona, researchers duplicated the symptoms of this condition by inducing dehydration in healthy individuals.
• There are few health practices as easy to adopt, with such rewards, as drinking water.