Research Studies & Publications
Health
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Scientific Opinion on Dietary Reference Values for water
European Food Safety Authority (EFSA), Parma, Italy, EFSA Journal - March 2010
This Opinion of the EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA) deals with the setting of dietary reference values for water for specific age groups. Adequate Intakes (AI) have been defined derived from a combination of observed intakes in population groups with desirable osmolarity values of urine and desirable water volumes per energy unit consumed. The reference values for total water intake include water from drinking water, beverages of all kind, and from food moisture and only apply to conditions of moderate environmental temperature and moderate physical activity levels (PAL 1.6).
Water as an essential nutrient: the physiological basis of hydration
E Jéquier and F Constant, EJCN - European Journal of Clinical Nutrition, September 2009
How much water we really need depends on water functions and the mechanisms of daily water balance regulation. The aim of this review is to describe the physiology of water balance and consequently to highlight the new recommendations with regard to water requirements.
Promotion and Provision of Drinking Water in Schools for Overweight Prevention: Randomized, Controlled Cluster Trial
Rebecca Muckelbauer, MSc, Lars Libuda, MSc, Kerstin Clausen, PhD, André Michael Toschke, MD, MSc, MPH, Thomas Reinehr, MD, and Mathilde Kersting, PhD, Pediatrics-- Official Journal of the American Academy of Pediatrics, April 2009
Our environmental and educational, school-based intervention proved to be effective in the prevention of overweight among children in elementary school, even in a population from socially deprived areas.
Just Add Water
Dan Negoianu, Stanley Goldfarb, Journal of the American Society of Nephrology, June 2008
To summarize the conclusions of other, more exhaustive reviews: There is no clear evidence of benefit from drinking increased amounts of water. Although we wish we could demolish all of the urban myths found on the Internet regarding the benefits of supplemental water ingestion, we concede there is also no clear evidence of lack of benefit. In fact, there is simply a lack of evidence in general. Given the central role of water not only in our bodies but also in our profession, it seems a deficit worthy of repletion.
Pediatric Emergency Department Visits for Diarrheal Illness Increased After Release of Undertreated Sewage
Ryan L. Redman, MDa, Cheryl A. Nenn, MSb, Daniel Eastwood, MSa and Marc H. Gorelick, MD, MSCEa, Pediatrics, December 2007
Emergency department visits for diarrheal illness increased significantly after 2 events of release of partially treated sewage into area waterways. These data suggest a potentially harmful effect of such practices.
Soft Drink Consumption and Risk of Developing Cardiometabolic Risk Factors and the Metabolic Syndrome in Middle-Aged Adults in the Community
Ravi Dhingra, MD; Lisa Sullivan, PhD; Paul F. Jacques, PhD; Thomas J. Wang, MD; Caroline S. Fox, MD; James B. Meigs, MD, MPH; Ralph B. D'Agostino, PhD; J. Michael Gaziano, MD, MPH; Ramachandran S. Vasan, MD, Circulation, July 2007
Consumption of soft drinks has been linked to obesity in children and adolescents, but it is unclear whether it increases metabolic risk in middle-aged individuals. Methods and Results - We related the incidence of metabolic syndrome and its components to soft drink consumption in participants in the Framingham Heart Study (6039 person-observations, 3470 in women; mean age 52.9 years) who were free of baseline metabolic syndrome. Metabolic syndrome was defined as the presence of 3 of the following: waist circumference 35 inches (women) or 40 inches (men); fasting blood glucose 100 mg/dL; serum triglycerides 150 mg/dL; blood pressure 135/85 mm Hg; and high-density lipoprotein cholesterol <40 mg/dL (men) or <50 mg/dL (women). Multivariable models included adjustments for age, sex, physical activity, smoking, dietary intake of saturated fat, trans fat, fiber, magnesium, total calories, and glycemic index. Cross-sectionally, individuals consuming 1 soft drink per day had a higher prevalence of metabolic syndrome (odds ratio [OR], 1.48; 95% CI, 1.30 to 1.69) than those consuming <1 drink per day. On follow-up (mean of 4 years), new-onset metabolic syndrome developed in 765 (18.7%) of 4095 participants consuming <1 drink per day and in 474 (22.6%) of 2059 persons consuming 1 soft drink per day. Consumption of 1 soft drink per day was associated with increased odds of developing metabolic syndrome (OR, 1.44; 95% CI, 1.20 to 1.74), obesity (OR, 1.31; 95% CI, 1.02 to 1.68), increased waist circumference (OR, 1.30; 95% CI, 1.09 to 1.56), impaired fasting glucose (OR, 1.25; 95% CI, 1.05 to 1.48), higher blood pressure (OR, 1.18; 95% CI, 0.96 to 1.44), hypertriglyceridemia (OR, 1.25; 95% CI, 1.04 to 1.51), and low high-density lipoprotein cholesterol (OR, 1.32; 95% CI 1.06 to 1.64). Conclusions - In middle-aged adults, soft drink consumption is associated with a higher prevalence and incidence of multiple metabolic risk factors.
Bottled Water Myths: Separating Fact from Fiction
Carol Rees Parrish, R.D., M.S., Practical Gastroenterology, May 2007
Based on the evidence available to date, it appears the true health risks (if any) related to drinking commercially manufactured bottled water or water in refillable plastic bottles may or may not come from the plastic itself. Further study is warranted to determine if poly-carbonate plastics can cause harm to humans. Consumers should focus more on the quality of the drinking water, particularly from a microbe perspective as this point is indisputable, rather than chemicals leaching from the container. Municipal treated water is highly regulated, and is certainly safe to recommend for consumption. Bottled water is regulated, but not as stringently as municipally treated water. Consumers need to be aware that the quality of commercially manufactured bottled waters is quite variable, depending on the quality of the original water source as well as treatment(s) used
to eliminate microbes in the final product. Anyone reusing plastic bottles should wash them thoroughly after each use with a mild detergent, and carefully inspect them for cracks or thinning before using them again. The better - and safer -alternative is to pitch the plastic bottle in the recycle bin and not reuse it at all. Allowing the bottle to be commercially recycled protects the consumer, and promotes a better environment for all.
Assessing Hydration Status: The Elusive Gold Standard
Lawrence E. Armstrong, Journal of the American College of Nutrition, Vol. 26, No. 5, 575S-584S, 2007
Acknowledging that total body water (TBW) turnover is complex, and that no measurement is valid for all situations, this review evaluates 13 hydration assessment techniques. Although validated laboratory methods exist for TBW and extracellular volume, no evidence incontrovertibly demonstrates that any concentration measurement, including plasma osmolality (Posm), accurately represents TBW gain and loss during daily activities. Further, one blood or urine sample cannot validly represent fluctuating TBW and fluid compartments. Future research should (a) evaluate novel techniques that assess hydration in real time and are precise, accurate, reliable, non-invasive, portable, inexpensive, safe, and simple; and (b) clarify the relationship between Posm and TBW oscillations in various scenarios.
Dehydration and Cognitive Performance
Ann C. Grandjean, Nicole R. Grandjean, Journal of the American College of Nutrition, Vol. 26, No. 5, 549S-554S, 2007
Human neuropsychology investigates brain-behavior relationships, using objective tools (neurological tests) to tie the biological and behavior aspects together. The use of neuropsychological assessment tools in assessing potential effects of dehydration is a natural progression of the scientific pursuit to understand the physical and mental ramifications of dehydration. It has long been known that dehydration negatively affects physical performance. Examining the effects of hydration status on cognitive function is a relatively new area of research, resulting in part from our increased understanding of hydration's impact on physical performance and advances in the discipline of cognitive neuropsychology. The available research in this area, albeit sparse, indicates that decrements in physical, visuomotor, psychomotor, and cognitive performance can occur when 2% or more of body weight is lost due to water restriction, heat, and/or physical exertion. Additional research is needed, especially studies designed to reduce, if not remove, the limitations of studies conducted to date.
Exercise, Heat, Hydration and the Brain
R.J. Maughan, S.M. Shirreffs, P. Watson, Journal of the American College of Nutrition, Vol. 26, No. 5, 604S-612S, 2007
The performance of both physical and mental tasks can be adversely affected by heat and by dehydration. There are well-recognized effects of heat and hydration status on the cardiovascular and thermoregulatory systems that can account for the decreased performance and increased sensation of effort that are experienced in the heat. Provision of fluids of appropriate composition in appropriate amounts can prevent dehydration and can greatly reduce the adverse effects of heat stress. There is growing evidence that the effects of high ambient temperature and dehydration on exercise performance may be mediated by effects on the central nervous system. This seems to involve serotonergic and dopaminergic functions. Recent evidence suggests that the integrity of the blood brain barrier may be compromised by combined heat stress and dehydration, and this may play a role in limiting performance in the heat.
How Primary Care Providers Might Review Evidence on Hydration
Kathryn M. Kolasa, Carolyn J. Lackey, David G. Weismiller, Journal of the American College of Nutrition, Vol. 26, No. 5, 570S-574S, 2007
Primary care providers (PCPs) are increasing their use of evidence-based medicine (EBM) in the care they give patients. They evaluate the available evidence to determine if it applies to their patients and seek to complement their clinical experience with EBM to improve patient outcomes. In evidence-based practices, patient oriented data are valued more highly than disease oriented evidence. More than 8 million biomedical articles are published annually, but only an estimated 2% of those are relevant to improved patient outcomes (POEMs - patient oriented evidence that matters). This paper describes some of the tools used by PCPs to search for evidence and the decision-making process used to determine if they will change their practice. Understanding how PCPs evaluate research findings and other evidence can help hydration researchers frame their research questions and study reports.
Hydration and Cognition: A Critical Review and Recommendations for Future Research
Harris R. Lieberman, Journal of the American College of Nutrition, Vol. 26, No. 5, 555S-561S, 2007
The limited literature on the effects of dehydration on human cognitive function is contradictory and inconsistent. Although it has been suggested that decrements in cognitive performance are present in the range of a 2 to 3% reduction in body weight, several dose-response studies indicate dehydration levels of 1% may adversely affect cognitive performance. When a 2% or more reduction in body weight is induced by heat and exercise exposure, decrements in visual-motor tracking, short-term memory and attention are reported, but not all studies find behavioral effects in this range. Future research should be conducted using dose-response designs and state-of-the-art behavioral methods to determine the lowest levels of dehydration that produce substantive effects on cognitive performance and mood. Confounding factors, such as caffeine intake and the methods used to produce dehydration, need to be considered in the design and conduct of such studies. Inclusion of a positive control condition, such as alcohol intake, a hypnotic drug, or other treatments known to produce adverse changes in cognitive performance should be included in such studies. To the extent possible, efforts to blind both volunteers and investigators should be an important consideration in study design.
Hydration and Disease
Friedrich Manz, Journal of the American College of Nutrition, Vol. 26, No. 5, 535S-541S, 2007
Many diseases have multifactorial origins. There is increasing evidence that mild dehydration plays a role in the development of various morbidities. In this review, effects of hydration status on acute and chronic diseases are depicted (excluding the acute effects of mild dehydration on exercise performance, wellness, cognitive function, and mental performance) and categorized according to four categories of evidence (I-IV). Avoidance of a high fluid intake as a precautionary measure may be indicated in patients with cardiovascular disorders, pronounced chronic renal failure (III), hypoalbuminemia, endocrinopathies, or in tumor patients with cisplatin therapy (IIb) and menace of water intoxication. Acute systemic mild hypohydration or dehydration may be a pathogenic factor in oligohydramnios (IIa), prolonged labor (IIa), cystic fibrosis (III), hypertonic dehydration (III), and renal toxicity of xenobiotica (Ib). Maintaining good hydration status has been shown to positively affect urolithiasis (Ib) and may be beneficial
in treating urinary tract infection (IIb), constipation (III), hypertension (III), venous thromboembolism (III), fatal coronary heart disease (III), stroke (III), dental disease (IV), hyperosmolar hyperglycemic diabetic ketoacidosis (IIb), gallstone disease (III), mitral valve prolapse (IIb), and glaucoma (III). Local mild hypohydration or dehydration may play a critical role in the pathogenesis of several bronchopulmonary disorders like exercise asthma (IIb) or cystic fibrosis (Ib). In bladder and colon cancers, the evidence on hydration status' effects is inconsistent.
Hydration and Physical Performance
Bob Murray, Journal of the American College of Nutrition, Vol. 26, No. 5, 542S-548S, 2007
There is a rich scientific literature regarding hydration status and physical function that began in the late 1800s, although the relationship was likely apparent centuries before that. A decrease in body water from normal levels (often referred to as dehydration or hypohydration) provokes changes in cardiovascular, thermoregulatory, metabolic, and central nervous function that become increasingly greater as dehydration worsens. Similarly, performance impairment often reported with modest dehydration (e.g., -2% body mass) is also exacerbated by greater fluid loss. Dehydration during physical activity in the heat provokes greater performance decrements than similar activity in cooler conditions, a difference thought to be due, at least in part, to greater cardiovascular and thermoregulatory strain associated with heat exposure. There is little doubt that performance during prolonged, continuous exercise in the heat is impaired by levels of dehydration >= -2% body mass, and there is some evidence that lower levels of dehydration can also impair performance even during relatively short-duration, intermittent exercise. Although additional research is needed to more fully understand low-level dehydration's effects on physical performance, one can generalize that when performance is at stake, it is better to be well-hydrated than dehydrated. This generalization holds true in the occupational, military, and sports settings.
Key teaching points:
- Dehydration during physical activity is commonplace because voluntary fluid intake is often less than fluid loss through sweating.
- Dehydration results in unavoidable, negative effects on physiological function and exercise performance. The magnitude of the effects of dehydration is exacerbated by increases in heat stress, exercise duration, and exercise intensity.
- Adequate drinking during exercise helps attenuate the reductions in blood volume, cardiac output, muscle blood flow, skin blood flow, the rise in core temperature, and the impairment in exercise performance that accompany dehydration.
Hydration at the Work Site
Robert W. Kenefick, Michael N. Sawka, Journal of the American College of Nutrition, Vol. 26, No. 5, 597S-603S, 2007
When performing physical work, sweat output often exceeds water intake, producing a body water deficit or dehydration. Specific to the work place, dehydration can adversely affect worker productivity, safety, and morale. Legislative bodies in North America such as the Occupational Safety and Health Administration (OSHA) and the American Conference of Governmental Industrial Hygienists (ACGIH) recommend replacing fluids frequently when exposed to heat stress, such as one cup (250 ml) every 20 minutes when working in warm environments. However, the majority of legislative guidelines provide vague guidance and none take into account the effects of work intensity, specific environments, or protective clothing. Improved occupational guidelines for fluid and electrolyte replacement during hot weather occupational activities should be developed to include recommendations for fluid consumption before, during, and after work.
Hydration in Children
Friedrich Manz, Journal of the American College of Nutrition, Vol. 26, No. 5, 562S-569S, 2007
Water supply is a basic public problem. In modern science, three periods with different approaches to define recommended water intake in adults can be distinguished. Pediatricians agree that hydration in children may be optimal only in breastfed infants. More data are required on the health effects of different hydration states and varying water intakes in particular age and gender groups to define optimal ranges of water intake. The fetus grows in an exceptionally well-hydrated environment. Water metabolism shows several peculiarities in preterm and term infants. Infant diarrhea remains a major topic of basic and clinical research. Water intoxication in infants, toddlers, and children is rare and can only be found in exceptional circumstances. Hydration status characterized by hyponatremia may play a role in the pathogenesis of febrile convulsions in toddlers. There is increasing indirect evidence that spontaneous drinking behavior of a population may be fixed and anchored in the age range of toddlers.
Sex differences in hydration status are common, but not obligatory. What causes theses differences? What is behind the various circadian rhythms of urine osmolality in children? At what age and in what quantities can alcohol and caffeine consumption be tolerated? How can individual susceptibility be defined? Reflecting on the modern epidemic of obesity in children and adolescents, a public consensus concerning use and misuse of sweetened drinks seems mandatory. Dietary reference intakes of water refer to 24-hour intake. In nutritional counseling, food and meal-based dietary advice is primarily given. Young parents are confronted with a flood of advice of varying quality. Recommendations on fluid consumption should be collated and revised.
Hydration Needs throughout the Lifespan
Sheila M. Campbell, Journal of the American College of Nutrition, Vol. 26, No. 5, 585S-587S, 2007
In 2004, the Institute of Medicine (IOM) issued a report presenting reference intake information about water, sodium, potassium, and other electrolytes for Americans and Canadians [1]. The report established, for the first time, adequate intakes (AI) for total water (from drinking water, beverages, and food) for healthy people. An AI is the recommended average daily intake level based on observed or experimentally-determined approximations or estimates of nutrient intake by a group or groups of apparently health people that are assumed to be adequate. The AI for water is based on US survey data. The recommendations about water intake are for healthy populations - they do not apply to at-risk groups.
Limitations of Data on Fluid Intake
Victor L. Fulgoni, III, Journal of the American College of Nutrition, Vol. 26, No. 5, 588S-591S, 2007
The Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate, provided extensive tables of data on total water intake, water intake from beverages and water intake from foods; however, very little information was provided about the specific details of these analyses. Reported total water intake varied with gender and somewhat with age and suggested that further sources of variation in total water intake were due to differences in body size, physical activity, and climatic exposure. Objective and Methods: In an attempt to better understand the variation in reported water intake, we examined water intake from foods and beverages and plain water intake in the National Health and Nutrition Examination Surveys (NHANES), 1999-2002. Results: Non-Hispanic black children (4 to 18 years) had less water from food and beverages (~ 0.15 L/day) than non-Hispanic whites and Hispanics. Non-Hispanic black children had less (~ 0.15 L/day) plain water than other ethnicities. Adult non-Hispanic whites had more water intake from food and beverages (~ 0.4 L/day) and non-Hispanic blacks had less (~ 0.2 L/day) than Hispanics and Other ethnic group. Non-Hispanic black adults had less (~ 0.2 L/day) plain water than non-Hispanic whites and the Other ethnic group but had similar plain water consumption as Hispanics. Conclusion: These data indicate further investigation into the sources of variation of water intake should include consideration of ethnic differences.
Mechanisms and Significance of Cell Volume Regulation
Florian Lang, Journal of the American College of Nutrition, Vol. 26, No. 5, 613S-623S, 2007
Survival of human and animal cells requires avoidance of excessive alterations of cell volume. The osmolarity amassed by cellular accumulation of organic substances must be compensated by lowering cytosolic ion concentrations. The Na+/K+ ATPase extrudes Na+ in exchange for K+, which can permeate the cell membrane through K+ channels. K+ exit generates a cell-negative potential difference across the cell membrane, driving the exit of anions such as Cl-. The low cytosolic Cl- concentrations counterbalance the excess cellular osmolarity by organic substances. Cell volume regulation following cell swelling involves releasing ions through activation of K+ channels and/or anion channels, KCl-cotransport, or parallel activation of K+/H+ exchange and Cl-/HCO3- exchange. Cell volume regulation following cell shrinkage involves accumulation of ions through activation of Na+, K+, 2Cl- cotransport, Na+/H+ exchange in parallel to Cl-/HCO3- exchange, or Na+ channels. The Na+ taken up is extruded by the Na+/K+ ATPase in exchange for K+. Shrunken cells further accumulate organic osmolytes such as sorbitol and glycerophosphorylcholine, and monomeric amino acids by altered metabolism and myoinositol (inositol), betaine, taurine, and amino acids by Na+ coupled transport. They
release osmolytes during cell swelling. Challenges of cell volume homeostasis include transport, hormones, transmitters, and drugs. Moreover, alterations of cell volume participate in the machinery regulating cell proliferation and apoptotic cell death. Deranged cell volume regulation significantly contributes to the pathophysiology
of several disorders such as liver insufficiency, diabetic ketoacidosis, hypercatabolism, fibrosing disease, sickle cell anemia, and infection.
Role of Whole Foods in Promoting Hydration after Exercise in Humans
Rick L. Sharp, Journal of the American College of Nutrition, Vol. 26, No. 5, 592S-596S, 2007
Various reports indicate that humans receive 20-25% of their daily water intake from food. Fruits, vegetables and other high-moisture foods, therefore, make an important contribution to total fluid intake. In addition, co-ingestion of other nutrients and ingredients can impact drinking behavior, absorption, distribution and retention of water, all of which contribute to the person's hydration state. Therefore, a food's hydration value derives from the interaction between its water content and the presence of these co-nutrients and ingredients. Research is reviewed in this paper showing increased voluntary fluid intake of young boys during exercise when the beverage is flavored and contains sodium chloride and carbohydrate. Additional research on rehydration after exercise and heat exposure showed improved recovery of plasma volume and fluid status when food was ingested before consuming water in the two hours after exercise. Collectively, these findings point to an interaction between fluid intake and co-ingested nutrients in regulating human hydration during and after exercise.
An approach for developing a national estimate of waterborne disease due to drinking water and a national estimate model application
Michael Messner, Susan Shaw, Stig Regli, Ken Rotert, Valerie Blank and Jeff Soller, Journal of Water and Health, Vol 04 No Suppl 2 pp 201–240, 2006
In this paper, the US Environmental Protection Agency (EPA) presents an approach and a national estimate of drinking water related endemic acute gastrointestinal illness (AGI) that uses information from epidemiologic studies. There have been a limited number of epidemiologic studies that have measured waterborne disease occurrence in the United States. For this analysis, we assume that certain unknown incidence of AGI in each public drinking water system is due to drinking water and that a statistical distribution of the different incidence rates for the population served by each system can be estimated to inform a mean national estimate of AGI illness due to drinking water. Data from public water systems suggest that the incidence rate of AGI due to drinking water may vary by several orders of magnitude. In addition, data from epidemiologic studies show AGI incidence due to drinking water ranging from essentially none (or less than the study detection level) to a rate of 0.26 cases per person-year. Considering these two perspectives collectively, and associated uncertainties, EPA has developed an analytical approach and model for generating a national estimate of annual AGI illness due to drinking water. EPA developed a national estimate of waterborne disease to address, in part, the 1996 Safe Drinking Water Act Amendments. The national estimate uses best available science, but also recognizes gaps in the data to support some of the model assumptions and uncertainties in the estimate. Based on the model presented, EPA estimates a mean incidence of AGI attributable to drinking water of 0.06 cases per year (with a 95% credible interval of 0.02–0.12). The mean estimate represents approximately 8.5% of cases of AGI illness due to all causes among the population served by community water systems. The estimated incidence translates to 16.4 million cases/year among the same population. The estimate illustrates the potential usefulness and challenges of the approach, and provides a focus for discussions of data needs and future study designs. Areas of major uncertainty that currently limit the usefulness of the approach are discussed in the context of the estimate analysis.
Hydration and Cognitive Function in Children
Kristen E. D'Anci, Florence Constant, Irwin H. Rosenberg, Nutritional Review, October 2006
Adequate fluid intake is critical for survival. While adults are at liberty to drink fluids as wanted, children and infants are dependent upon caregivers for food and fluid. Children are at greater risk for dehydration than adults due to their higher surface-to-mass ratio. Additionally, children have different thirst sensitivities and body cooling mechanisms than adults. Children differ from adults in total body water content, and boys and girls differ in body water content with maturation. Research in young adults shows that mild dehydration corresponding to only 1% to 2% of body weight loss can lead to significant impairment in cognitive function. Dehydration in infants is associated with confusion, irritability, and lethargy; in children, it may produce decrements in cognitive performance.
Beverage Intake in the United States
UNC Carolina Population Center, May 2006
Why a beverage panel? You are what you drink and we are drinking far too many calories from beverages. Starting a solution: The Beverage Guidance Panel was assembled to provide guidance on the relative health and nutritional benefits and risks of various beverage categories. The beverage panel was initiated by Barry M. Popkin. The Panel's purpose is to systematically review the literature on beverages and health and provide guidance to the consumer. And, also to develop a deeper dialog among the scientific community on overall beverage consumption patterns in the United States and the great potential to change this pattern as a way to improve health. Currently, Americans consume about 21% of their calories from beverages.
A New Proposed Guidance System for Beverage Consumption in the United States
Barry M. Popkin, Lawrence E. Armstrong, George M. Bray, Benjamin Caballero, Balz Frei,, Walter C. Willett, American Journal of Clinical Nutrition, 2006
The Beverage Guidance Panel was assembled to provide guidance on the relative health and nutritional benefits and risks of various beverage categories. The beverage panel was initiated by the first author. The Panel's purpose is to attempt to systematically review the literature on beverages and health and provide guidance to the consumer. An additional purpose of the Panel is to develop a deeper dialog among the scientific community on overall beverage consumption patterns in the United Sates and on the great potential to change this pattern as a way to improve health. Over the past several decades, levels of overweight and obesity have increased across all population groups in the United States. Concurrently, an increased daily intake of 150-300 kcal (for different age-sex groups) has occurred, with approximately 50% of the increased calories coming from the consumption of calorically sweetened beverages. The panel ranked beverages from the lowest to the highest value based on caloric and nutrient contents and related health benefits and risks. Drinking water was ranked as the preferred beverage to fulfill daily water needs and was followed in decreasing value by tea and coffee, low-fat (1.5% or 1%) and skim (nonfat) milk and soy beverages, noncalorically sweetened beverages, beverages with some nutritional benefits (fruit and vegetable juices, whole milk, alcohol, and sports drinks), and calorically sweetened, nutrient-poor beverages. The Panel recommends that the consumption of beverages with no or few calories should take precedence over the consumption of beverages with more calories.
Water-Induced Thermogenesis Reconsidered: The Effects of Osmolality and Water Temperature on Energy Expenditure after Drinking
Clive M. Brown, Abdul G. Dulloo, Jean-Pierre Montani, The Journal of Clinical Endocrinology & Metabolism, 2006
A recent study reported that drinking 500 ml of water causes a 30% increase in metabolic rate. If verified, this previously unrecognized thermogenic property of water would have important implications for weight-loss programs. However, the concept of a thermogenic effect of water is controversial because other studies have found that water drinking does not increase energy expenditure. Objective: The objective of the study was to test whether water drinking has a thermogenic effect in humans and, furthermore, determine whether the response is influenced by osmolality or by water temperature. Design: This was a randomized, crossover design. Setting: The study was conducted at a university physiology laboratory. Participants: Participants included healthy young volunteer subjects. Intervention: Intervention included drinking 7.5 ml/kg body weight ([~]518 ml) of distilled water or 0.9% saline or 7% sucrose solution (positive control) on different days. In a subgroup of subjects, responses to cold water (3 C) were tested. Main Outcome Measure: Resting energy expenditure, assessed by indirect calorimetry for 30 min before and 90 min after the drinks, was measured. Results: Energy expenditure did not increase after drinking either distilled water (P = 0.34) or 0.9% saline (P = 0.33). Drinking the 7% sucrose solution significantly increased energy expenditure (P < 0.0001). Drinking water that had been cooled to 3 C caused a small increase in energy expenditure of 4.5% over 60 min (P < 0.01). Conclusions: Drinking distilled water at room temperature did not increase energy expenditure. Cooling the water before drinking only stimulated a small thermogenic response, well below the theoretical energy cost of warming the water to body temperature. These results cast doubt on water as a thermogenic agent for the management of obesity.
The Rate of Bromate Decomposition in the Human Stomach: Phase I
Joseph A. Cotruvo Ph.D, Joseph Cotruvo & Associates LLC, Washington, DC, Jason Keith, B.S., Gilbert Gordon PhD, Gilbert Pacey PhD, Miami University, Richard Bull PhD, MoBull Associates, Richland, Washington, August 2004
Bromate is produced in drinking water and bottled water by the ozonation of bromide-containing water. Bromide can also be introduced to drinking water during chlorination as a contaminant during chlorine production.
This research explores the fate of bromate (and other reactive substances) in the stomach under relevant typical human physical characteristics and exposure conditions, so that the actual systemic uptake of bromate will be predictable under those conditions.
AAP - Soft Drinks in Schools
Committee on School Health, Pediatrics, January 2004
This statement is intended to inform pediatricians and other health care professionals, parents, superintendents, and school board members about nutritional concerns regarding soft drink consumption in schools. Potential health problems associated with high intake of sweetened drinks are 1) overweight or obesity attributable to additional calories in the diet; 2) displacement of milk consumption, resulting in calcium deficiency with an attendant risk of osteoporosis and fractures; and 3) dental caries and potential enamel erosion. Contracts with school districts for exclusive soft drink rights encourage consumption directly and indirectly. School officials and parents need to become well informed about the health implications of vended drinks in school before making a decision about student access to them. A clearly defined, district-wide policy that restricts the sale of soft drinks will safeguard against health problems as a result of over-consumption.
Hydration: Fluids for Life
Ann Grandjean, Sheila Campbell, ILSI North America, 2004
This monograph provides readers with an overview of current knowledge related to the functions of water, methods of determining hydration status, sources of water in the diet, and specific considerations for infants, children, physically active individuals, and the elderly. Recommended intakes, as specified by the FNB in the 2004 Dietary Reference Intakes for water, are also covered. For additional reading and more detailed explanations of the information herein, a list of references is provided.
"Drink at least eight glasses of water a day." Really? Is there scientific evidence for "8x8"?
Heinz Valtin, American Journal of Physiology - Regulatory, Integrative and Comparative Physiology, November 2002
Despite the seemingly ubiquitous admonition to "drink at least eight 8-oz glasses of water a day" (with an accompanying reminder that beverages containing caffeine and alcohol do not count), rigorous proof for this counsel appears to be lacking. This review sought to find the origin of this advice (called "8x8" for short) and to examine the scientific evidence, if any, that might support it. The search included not only electronic modes but also a cursory examination of the older literature that is not covered in electronic databases and, most importantly and fruitfully, extensive consultation with several nutritionists who specialize in the field of thirst and drinking fluids. No scientific studies were found in support of 8x8. Rather, surveys of food and fluid intake on thousands of adults of both genders, analyses of which have been published in peer-reviewed journals, strongly suggest that such large amounts are not needed because the surveyed persons were presumably healthy and certainly not overtly ill. This conclusion is supported by published studies showing that caffeinated drinks (and, to a lesser extent, mild alcoholic beverages like beer in moderation) may indeed be counted toward the daily total, as well as by the large body of published experiments that attest to the precision and effectiveness of the osmoregulatory system for maintaining water balance. It is to be emphasized that the conclusion is limited to healthy adults in a temperate climate leading a largely sedentary existence, precisely the population and conditions that the "at least" in 8x8 refers to. Equally to be emphasized, lest the message of this review be misconstrued, is the fact (based on published evidence) that large intakes of fluid, equal to andgreater than 8x8, are advisable for the treatment or prevention of some diseases and certainly are called for under special circumstances, such as vigorous work and exercise, especially in hot climates. Since it is difficult or impossible to prove a negative - in this instance, the absence of scientific literature supporting the 8x8 recommendation - the author invites communications from readers who are aware of pertinent publications.
Bottled Water: Better than Tap?
Anne Christiansen, FDA Consumer Magazine, July/August, 2002
Article discusses the benefits of bottled water over tap. Topics discussed include: types of bottled waters and regulations. One benefit stated in the article is the convenience of bottled water, "When she was growing up, Harrison, 34, might have grabbed a soft drink or juice on her way out the door. But for her kids, Harrison insists on what she thinks is a healthier choice--water. She says her children's young bodies need water as they play in the Oklahoma sun. Bottled water also contains no caffeine, no calories and no sugar. Plus, bottled water comes in convenient bottles, easy to tote from home to wherever the busy family goes." (Excerpt from article).
Virulence and Risk of HPC Bacteria in Human Population Groups
M.J. Allen and S.C. Edberg, International Journal of Food Protection, April 2002
A review of the literature, including animal and human feeding studies, analysis of virulence factors and outbreaks, demonstrates that HPC bacteria as enumerated on HPC culture media have not been established as a human health threat at any concentration in drinking water or foods.
Water, Other Fluids, and Fatal Coronary Heart Disease: The Adventist Health Study
Jacqueline Chan, Synnove F. Knutsen, Glen G. Blix, Jerry W. Lee, Gary E. Fraser, American Journal of Epidemiology, 2002
Whole blood viscosity, plasma viscosity, hematocrit, and fibrinogen are considered independent risk factors for coronary heart disease and can be elevated by dehydration. The associations between fatal coronary heart disease and intake of water and fluids other than water were examined among the 8,280 male and 12,017 female participants aged 38-100 years who were without heart disease, stroke, or diabetes at baseline in 1976 in the Adventist Health Study, a prospective cohort study. A total of 246 fatal coronary heart disease events occurred during the 6-year follow-up. High daily intakes of water (five or more glasses) compared with low (two or fewer glasses) were associated with a relative risk in men of 0.46 (95% confidence interval (CI): 0.28, 0.75; p trend = 0.001) and, in women, of 0.59 (95% CI: 0.36, 0.97). A high versus low intake of fluids other than water was associated with a relative risk of 2.47 (95% CI: 1.04, 5.88) in women and of 1.46 (95% CI: 0.7, 3.03) in men. All associations remained virtually unchanged in multivariate analysis adjusting for age, smoking, hypertension, body mass index, education, and (in women only) hormone replacement therapy. Fluid intake as a putative coronary heart disease risk factor may deserve further consideration in other populations or using other study designs.
Bacteriophages as Indicators for Enteric Viruses and Public Health Risks in Groundwaters
H. LeClerc, S.C. Edberg, V. Pierzo, J.M. Delattre, Journal of Applied Microbiology, January 2000
For more than 100 years there has been debate among microbiologists and public health practitioners concerning the role of drinking water monitoring for either pathogens or indicators.
This review summarizes the basic strengths and weaknesses of bacteriophages as indicators. Overall, the conclusion is that it is better to monitor for the indicators of fecal pollution rather than for specific pathogens.
Water Consumption and Nursing Characteristics of Infants by Race and Ethnicity
Keith Heller, Woosung Sohn, Brian A. Burt, Robert J. Feigal, Journal of Public Health Dentristry, 2000
The purpose of this project was to determine racial/ethnic differences in water consumption levels and nursing habits of children younger than 2 years old. Methods: Data from the 1994201396 Continuing Survey of Food Intakes by Individuals (CSFII) were used for these analyses. Water consumption and breast-feeding data on 946 children younger than 2 years old were used. Results: For black non-Hispanic children younger than 2 years old (n=121), 5.3 percent of the children were currently being breast fed. This percentage was less than that seen in other racial/ethnic groups. For white non-Hispanic children (n=620), this percentage was 10.8 percent; for Hispanic children (n=146), 12.2 percent; for "other" children, 18.5 percent (n=59). Black non-Hispanic children had the highest total water consumption (128.6 ml/kg/day) among all groups, white non-Hispanic had the lowest (113.2 ml/kg/day). These differences were not statistically significant in multivariate regression modeling. Black non-Hispanic children also drank moretap water (21.3 ml/kg/day) than white non-Hispanic children (12.7 ml/kg/day) and Hispanic children (14.9 ml/kg/day). The difference was statistically significant in multivariate regression modeling. Conclusions: The differences in breast feeding and water consumption observed among black children younger than 2 years of age could be a factor in the observed higher levels of fluorosis in black children compared to other children.
Water Consumption in the United States in 1994 and Implications for Water Fluoridation Policy
Keith Heller, Woosung Sohn, Brian A. Burt, Stephen A. Eklund, Journal of Public Health Dentistry, 1999
The purpose of this project was to describe current water consumption patterns and to compare them to findings from earlier studies. Current water consumption data also were used to reevaluate the association between water consumption and climate. These findings are of importance in estimating fluoride intake from fluoridated water. Methods: Findings from the 1994201396 Continuing Survey of Food Intakes by Individuals (CSFII) were compared to those from two earlier dietary studies, the 1977201378 Nationwide Food Consumption Survey (NFCS) and the pioneering research of Galagan and colleagues in the 1950s. Food consumption data were analyzed for 14,619 persons with food and beverage intake data for two 24-hour periods in the CSFII. Results: Increased consumption of infant formulas and decreased consumption of tap water and cow's milk were seen in the CSFII for infants compared to the NFCS. Older children and adults showed increased consumption of carbonated beverages and juices. While Galagan and colleagues found about a 60 percent increase in water consumption between the coldest (55°F) and warmest (85°F) conditions, only a 20 percent difference was seen between the winter and summer months in certain regions in the CSFII. Conclusions: No obvious strong or consistent association between water intake and month or season was apparent in these recent data. These findings are preliminary, and suggest that water fluoridation policy requires further research regarding water consumption and climate.
New Patterns of Drinking-Water Consumption: Results of a Pilot Study
P. Levallois, S. Gringas, J.P. Weber, R. Letarte, The Science of the Total Environment, January 1998
A pilot study on water consumption was carried out in the Qu$eacute;bec City region in April and May 1996 with 125 people using a 24-h recall plus a 2-day diary. Consumption of drinking water via liquid and food was assessed as well as the type of water consumed (tap, bottle or filtered water) and place of consumption (home or away from home). Most of the people (56%) were drinking some bottled water or filtered tap water and 25% of water intake was away from home. Food consumption was found to be a non-significant source of drinking-water intake. The average water consumption was nearly similar in exclusively tap-water consumers and bottled- or filtered-water consumers (1.5 vs. 1.7 1/day, P = 0.29) but two-thirds of the consumption in this last group is natural water, while it is mixed water in the bottled/filtered-water group. No significant difference in amounts consumed were found according to age, but older people drank hot beverages and soup more often. The present pilot-study was weakened by a low participation rate (14%). Incentive might be necessary to improve participation rate and data collection methods must also be simplified. A 24-h recall plus a 1-day diary seem sufficient and data on consumption could be limited to liquids, soups and cereals.