Dealing with diarrhoea

Children with severe dehydration, persistent diarrhea with dehydration, or bloody diarrhea with no signs of improvement must be hospitalized. In-patient care for a child with severe dehydration includes rapid intravenous (IV) fluid therapy. Children who can still drink should be given oral rehydration salts (ORS) solution while the health worker sets up the IV drip. Children with difficulty drinking should be given ORS as soon as the IV fluid therapy restores their ability to drink (within 3-4 hours for babies, or 1-2 hours for older children), since ORS amends mineral deficiencies more effectively than the IV fluids. The IV drip should be re-administered if the child still exhibits dehydration after 3 hours for older children or 6 hours for babies. If improvement is noted, health workers should encourage the mother to administer ORS and to breast feed frequently. Hospital personnel should observe the child for at least 6 hours before discharge. This allows them to be sure that mothers can maintain the child's fluid balance. Children with diarrhea for more than 14 days face malnutrition or death. Any child with persistent diarrhea who exhibits moderate or severe malnutrition and signs of dehydration and is less than 4 months old needs to be admitted to a hospital. Management of persistent diarrhea involves fluid replacement, appropriate diet, and treatment of associated infections, if needed. ORS is usually effective for persistent diarrhea, although in a few cases poor absorption of glucose may necessitate initial rehydration with IV therapy. Breast feeding is encouraged for infants. Older infants and young children should eat 6 times a day as soon as they are able to eat. Recommended diets for these children are a low lactose diet (milk, yogurt, or curds; cooked rice; oil; sugar/glucose) and a low starch and no lactose diet (eggs, chicken, or fish; cooked rice; oil; sugar/glucose). Children with serious infections may require nasogastric feeding at first. Shigella bacteria tend to be responsible for dysentery. Children with this bloody diarrhea should be treated with an antibiotic. If their condition does not improve and they are malnourished, less than 1 year old, were initially dehydrated, or have recently had measles, they need to be hospitalized. Drugs to reduce frequency of stools should never be given in cases of bloody diarrhea. Older babies and children should be given an extra meal and supplementary vitamins and minerals each day for two weeks.     

Strategies for Ensuring Good Hydration in the Elderly

Dehydration is a frequent etiology of morbidity and mortality in elderly people. It causes the hospitalization of many patients and its outcome may be fatal. Indeed, dehydration is often linked to infection, and if it is overlooked, mortality may be over 50%. Older individuals have been shown to have a higher risk of developing dehydration than younger adults. Modifications in water metabolism with aging and fluid imbalance in the frail elderly are the main factors to consider in the prevention of dehydration. Particularly, a decrease in the fat free mass, which is hy-drated and contains 73% water, is observed in the elderly due to losses in muscular mass, total body water, and bone mass. Since water intake is mainly stimulated by thirst, and since the thirst sensation decreases with aging, risk factors for dehydration are those that lead to a loss of autonomy or a loss of cognitive function that limit the access to beverages. The prevention of dehydration must be multidisci-plinary. Caregivers and health care professionals should be constantly aware of the risk factors and signs of dehydration in elderly patients. Strategies to maintain normal hydration should comprise practical approaches to induce the elderly to drink enough. This can be accomplished by frequent encouragement to drink, by offering a wide variety of beverages, by advising to drink often rather than large amounts, and by adaptation of the environment and medications as necessary.     

Cognitive performance and dehydration

No matter how mild, dehydration is not a desirable condition because there is an imbalance in the homeostatic function of the internal environment. This can adversely affect cognitive performance, not only in groups more vulnerable to dehydration, such as children and the elderly, but also in young adults. However, few studies have examined the impact of mild or moderate dehydration on cognitive performance. This paper reviews the principal findings from studies published to date examining cognitive skills. Being dehydrated by just 2% impairs performance in tasks that require attention, psychomotor, and immediate memory skills, as well as assessment of the subjective state. In contrast, the performance of long-term and working memory tasks and executive functions is more preserved, especially if the cause of dehydration is moderate physical exercise. The lack of consistency in the evidence published to date is largely due to the different methodology applied, and an attempt should be made to standardize methods for future studies. These differences relate to the assessment of cognitive performance, the method used to cause dehydration, and the characteristics of the participants. Key teaching points: This paper reviews the existing findings about the impact of dehydration in the main cognitive skills explored so far. Children and the elderly are the populations most vulnerable to dehydration. Healthy young adults are also at risk of a decrease in their cognitive performance when hydration is not adequate. Attention, psychomotor, and immediate memory skills, as well as assessment of the subjective state, are the brain capabilities most vulnerable to mild or moderate dehydration. The relationship between hydration and cognitive performance is an emerging area of study of undoubted practical interest in which much research still need to be carried out.     

Fluid-electrolyte balance during labor and exercise: concepts and misconceptions

Body water and electrolyte balance are essential to optimal physiological function and health. During exercise, work, or high temperatures, a significant level of dehydration can develop, and the ratio of extracellular to intracellular fluid can change, despite an ample supply of water. Physical and cognitive performance are impaired at 1-2% dehydration, and the body can collapse when water loss approaches 7%. Because fluid needs and intakes vary, formulating one general guideline for fluid replacement is difficult. Knowing the amount of water lost in sweat may enable predicting fluid needs via mathematical models for industrial, athletic, and military scenarios. Sodium imbalance might result from excessive Na+ loss or from gross overhydration. In most work or exercise lasting < 3-4 hr, the major concern is that fluid be available to prevent heat-related illnesses, which can be prevented if fluid and electrolyte losses are balanced with intake, using the recommendations presented.     

Dehydration due to gastro-enteritis in children

Gastroenteritis is the commonest cause of dehydration in children. Infants and young children dehydrate more easily than adults if fluid intake is insufficient or fluid loss too high because of the combination of a large extracellular volume, a large insensible loss and a mediocre concentrating capacity of the kidney. Fluid loss due to gastroenteritis is often accompanied by electrolyte and acid-base disturbances. Oral rehydration with oral rehydration salts (ORS) is nearly always possible. Re-evaluation after 6 hours is advised especially in young children. Early (< 6-24 hours) resumption of feeding is important. If rehydration with frequent small amounts of ORS at home fails, continuous nasogastric tube feeding in the hospital is a good alternative. In dehydration exceeding 10% of body weight intravenous rehydration is necessary.     

Hydration and cognitive performance

A clinical link exists between severe dehydration and cognitive performance. Using rapid and severe water loss induced either by intense exercise and/or heat stress, initial studies suggested there were alterations in short-term memory and cognitive function related to vision, but more recent studies have not all confirmed these data. Some studies argue that water loss is not responsible for the observations made, and studies compensating water losses have failed to prevent the symptoms. Studies in children have suggested that drinking extra water helps cognitive performance, but these data rely on a small number of children. In older adults (mean age around 60) the data are not strong enough to support a relationship between mild dehydration and cognitive function. Data on frail elderly and demented people are lacking. Methodological heterogeneity in these studies are such that the relationship between mild dehydration and cognitive performance cannot be supported.     

Relationship of breast-feeding and hand-washing with dehydration in infants with diarrhoea due to Escherichia coli

This prospective cohort study was carried out in the neonatal unit of the Yangon Children Hospital, Myanmar, to gather more information on the types of feedings and hand-washing practices of mothers as the determinant of severe dehydration in infants with acute diarrhoea due to Escherichia coli. The study subjects included 100 infants with diarrhoea, aged less than 4 months, admitted to the hospital from June 1997 to May 1998. Data on isolation of E. coli from rectal swab samples, types of feedings, hand-washing practices, and dehydration status were collected. Of the 100 cases, E. coli was isolated from rectal swab samples of 48 infants. Of these 48 cases, 28 had some dehydration and 20 had severe dehydration. Exclusive breast-feeding was observed only in the age group < 1 and > 1-2 month(s). The association of the severity of dehydration with other types of feedings compared to exclusive breast-feeding was not statistically significant. In this study, most mothers washed their hands with water only after cleansing their children's defaecation, and before and after feeding their children. The severity of dehydration was statistically significant in hand-washing practices when compared to washing with water only and washing with soap and water. This study has shown the association between types of feedings and hand-washing practices with dehydration in infants with acute diarrhoea due to E. coli. The results of the study suggest that there is a need for appropriate intervention programmes to promote exclusive breast-feeding and hand-washing practices with soap and water after cleansing children's defaecation, and before and after feeding children.     

Identifying Infants and Toddlers at High Risk for Persistent Delays

ObjectivesLittle is known about the extent to which a developmental delay identified in infancy persists into early childhood. This study examined the persistence of developmental delays in a large nationally representative sample of infants and toddlers who did not receive early intervention. Methods In a sample (n ≈ 8700) derived from the early childhood longitudinal study, birth cohort, we examined developmental changes between 9 and 24 months. Motor and cognitive delays were categorized as none, mild, and moderate/severe. Adjusted ordinal logistic regression models estimated the likelihood of worse developmental delay at 24 months. Results About 24 % of children had a cognitive delay and 27 % had a motor delay at either 9- or 24-months. About 77 % of children with mild and 70 % of children with moderate/severe cognitive or motor developmental delay at 9-months had no delay at 24-months. Children with mild cognitive delay at 9-months had 2.4 times the odds of having worse cognitive function at 24-months compared to children with no cognitive delay at 9 months. Children with moderate/severe cognitive delay at 9-months had three times the odds of having worse cognitive abilities at 24-months than children who had no cognitive delay at 9-months. Similar results were found for motor skills. Conclusions Developmental delays in infants are changeable, often resolving without treatment. This work provides knowledge about baseline trajectories of infants without and without cognitive and motor delays. It documents the proportion of children’s delays that are likely to be outgrown without EI and the rate at which typically-developing infants are likely to display developmental delays at 2-years of age.     

Citrate can effectively replace bicarbonate in oral rehydration salts for cholera and infantile diarrhoea

This study investigated the therapeutic effectiveness of oral rehydration salt (ORS) solutions containing trisodium citrate (ORS-citrate) in place of sodium bicarbonate (ORS-bicarbonate). 74 children with cholera and 34 infants and children under 2 years of age with infantile diarrhea, all of whom had moderate to severe dehydration, were randomly assigned to 1 of the 2 treatment solution groups. Children with severe dehydration were 1st rehydrated with intravenous fluid followed by maintenance therapy with ORS solution (bicarbonate or citrate), while those with moderate dehydration received either ORS-bicarbonate or ORS-citrate during both the initial and the maintenance phases of therapy. Treatment effectiveness was assessed by comparing the success rates, stool output, ORS intake, gain in body weight, changes in erythrocyte volume fraction and plasma specific gravity, correction of acidosis, and maintenance of electrolyte balance. Of the children with cholera, 92% of those who received ORS-citrate and 86% of those who received ORS-bicarbonate were successfully treated. Of the children under 2 years of age with infantile diarrhea, 100% of those who received ORS-citrate and 94% of those who received ORS-bicarbonate were treated successfully. The results indicated that treatment with ORS-citrate is as successful as that with ORS-bicarbonate in terms of its ability to rehydrate, correct the acidosis, and maintain electrolyte concentrations. Thus, trisodium citrate dihydrate, which has the a advantage of a longer shelf-life in hot and humid climates, can effectively replace sodium bicarbonate in the standard ORS solution if used as an adjunct to standard hydration and antibiotic therapy in children with severe cholera or as the only treatment in children with infantile diarrhea assocated with less severe dehydration.     

Dehydration Influences Mood and Cognition: A Plausible Hypothesis?

The hypothesis was considered that a low fluid intake disrupts cognition and mood. Most research has been carried out on young fit adults, who typically have exercised, often in heat. The results of these studies are inconsistent, preventing any conclusion. Even if the findings had been consistent, confounding variables such as fatigue and increased temperature make it unwise to extrapolate these findings. Thus in young adults there is little evidence that under normal living conditions dehydration disrupts cognition, although this may simply reflect a lack of relevant evidence. There remains the possibility that particular populations are at high risk of dehydration. It is known that renal function declines in many older individuals and thirst mechanisms become less effective. Although there are a few reports that more dehydrated older adults perform cognitive tasks less well, the body of information is limited and there have been little attempt to improve functioning by increasing hydration status. Although children are another potentially vulnerable group that have also been subject to little study, they are the group that has produced the only consistent findings in this area. Four intervention studies have found improved performance in children aged 7 to 9 years. In these studies children, eating and drinking as normal, have been tested on occasions when they have and not have consumed a drink. After a drink both memory and attention have been found to be improved.     

Total energy expenditure and physical activity level in healthy young Swedish children 9 or 14 months of age

OBJECTIVES: To measure total energy expenditure (TEE) and total body water (TBW) in healthy Swedish children 9 or 14 months of age. To compare their TEE with current recommendations for energy intake. To define their body composition and relate this to energy expenditure. DESIGN:: Children were investigated at 9 or 14 months. The following variables were measured: TEE and TBW (by the doubly labelled water method), weight and length. Total body fat (TBF), sleeping metabolic rate, activity energy expenditure and physical activity level (PAL) were calculated. SUBJECTS: Thirty infants 9 months of age and 29 children 14 months of age. RESULTS:: TEE was 323+/-38, 322+/-29, 313+/-23 and 331+/-28 kJ/kg/day in 9-month-old girls, 9-month-old boys, 14-month-old girls and 14-month-old boys, respectively. At 9 months of age girls and boys contained 29.6+/-4.8 and 29.7+/-4.5% TBF, respectively. At 14 months the corresponding figures were 29.1+/-4.3 and 28.2+/-4.3%. There was a significant negative relationship between PAL and %TBF (r=-0.81, P<0.001, n=59). CONCLUSIONS: Measured TEE plus calculated energy cost of growth confirm previous estimates that the physiological energy requirements of children 9 and 14 months of age are 15-20% lower than current recommendations for energy intake. One possible interpretation of the relationship between PAL and %TBF is that children with a high TBF content are less physically active than children with less TBF. However, this relationship needs further studies.     

Cognitive Performance and Dehydration

No matter how mild, dehydration is not a desirable condition because there is an imbalance in the homeostatic function of the internal environment. This can adversely affect cognitive performance, not only in groups more vulnerable to dehydration, such as children and the elderly, but also in young adults. However, few studies have examined the impact of mild or moderate dehydration on cognitive performance. This paper reviews the principal findings from studies published to date examining cognitive skills. Being dehydrated by just 2% impairs performance in tasks that require attention, psychomotor, and immediate memory skills, as well as assessment of the subjective state. In contrast, the performance of long-term and working memory tasks and executive functions is more preserved, especially if the cause of dehydration is moderate physical exercise. The lack of consistency in the evidence published to date is largely due to the different methodology applied, and an attempt should be made to standardize methods for future studies. These differences relate to the assessment of cognitive performance, the method used to cause dehydration, and the characteristics of the participants.

Key teaching points:

• This paper reviews the existing findings about the impact of dehydration in the main cognitive skills explored so far.

• Children and the elderly are the populations most vulnerable to dehydration.

• Healthy young adults are also at risk of a decrease in their cognitive performance when hydration is not adequate.

• Attention, psychomotor, and immediate memory skills, as well as assessment of the subjective state, are the brain capabilities most vulnerable to mild or moderate dehydration.

• The relationship between hydration and cognitive performance is an emerging area of study of undoubted practical interest in which much research still need to be carried out.

     

提高儿童青少年饮水素养 加强水合状态与健康研究

摄入充足水分、维持身体适宜水合状态,对于促进身体健康至关重要.儿童青少年进行身体活动时,由于运动强度、能量消耗和环境温湿度的不同,对水的需要量也不同,出现饮水不足和脱水状态的风险更高.但水的重要性未得到足够重视,儿童青少年饮水健康素养有待提高.儿童青少年普遍存在饮水不足和处于脱水状态的现象,一定程度的脱水会降低其认知能力和身体活动能力,给予饮水健康宣教或饮水干预后有所改善.有必要开展更多儿童青少年饮水行为调查、水合状态与健康影响的研究和饮水健康宣教,提高儿童青少年饮水健康素养,以促进足量饮水、合理选择饮水类型和维持适宜水合状态,进而促进身体健康.     

Improving hydration in children: A sensible guide

Water is essential for health and vital for all bodily functions. If water losses are not replaced then dehydration can occur and even mild dehydration is associated with negative effects on health including impaired cognitive function. Studies in schoolchildren have found that many are arriving at school with a hydration deficit and, once they arrive, they are not drinking enough fluid throughout the day to maintain adequate hydration levels, thus potentially affecting their performance at school. Therefore, there is a need to highlight the importance of adequate hydration among schoolchildren. However, there is often confusion among parents, carers, health professionals and teachers about how much fluid children need to drink, as well as what drinks are most appropriate. This article provides a summary of the development of the Healthy hydration guide for children that was produced to help parents, carers, health professionals and teachers, and indeed children themselves, to choose a healthy balance of drinks to ensure optimal performance and health. It is hoped this resource will help children aged 4–13 years to establish healthy drinking behaviours.     

Evaluation of nuclear magnetic resonance spectroscopy for determination of deuterium abundance in body fluids: application to measurement of total-body water in human infants

Nuclear magnetic resonance (NMR) spectroscopy was used to quantitate abundance of 2H in body water of human infants. This method provides precise measurement of total-body water without the extensive sample preparation requirements of previously described methods for determination of 2H content in body fluids. 2H2O (1 g/kg body weight) was administered to infants and saliva and urine were collected for up to 5 h. An internal standard was added directly to the fluid specimen and 2H enrichment in water was measured by NMR spectroscopy. Working range of deuterium abundance was 0.04-0.32 atom %. Coefficients of variation for saliva samples at 0.20 atom % 2H was 1.97%. 2H content in urine and saliva water reached a plateau by 4 h after administration, and amounts in the two fluids were virtually identical. Mean total-body water determination for six infants was 58.3 +/- 5.8% of body weight (range 53-66%).     

Am I Drinking Enough? Yes,No, and Maybe

Adequate fluid intake can be dually defined as a volume of fluid (from water, beverages, and food) sufficient to replace water losses and provide for solute excretion. A wide range of fluid intakes are compatible with euhydration, whereby total body water varies narrowly from day to day by 600 to 900 mL (<1% body mass). One measure of fluid intake adequacy involves enough fluid to prevent meaningful body water deficits outside this euhydration range (i.e., dehydration). Another measure of fluid intake adequacy involves enough fluid to balance the renal solute load, which can vary widely inside the euhydration range. The subtle but important distinction between the 2 types of adequacy may explain some of the ambiguity surrounding the efficacy of hydration status markers. Both perspectives of fluid intake adequacy are discussed in detail and a simple tool is reviewed that may help healthy, active, low-risk populations answer the question, “Am I drinking enough?”

Key Teaching Points

? Adequate fluid intake can be dually defined as a volume of fluid (from water, beverages, and food) sufficient to replace water losses and provide for solute excretion.

? Fluid needs can differ greatly among individuals due to variation in the factors that influence both water loss and solute balance; thus, adequacy is consistent with a wide range of fluid intakes and is better gauged using hydration assessment methods.

? Adequacy of fluid intake for replacing meaningful water losses (dehydration) can be assessed simply, inexpensively, and with reasonable fidelity among healthy, active, low-risk individuals.

? Adequacy of fluid intake for solute excretion per se can also be assessed among individuals but is more difficult to define and less practical to measure.     

Short-term regulation of food intake in children, young adults and the elderly

OBJECTIVE: The present study investigated the effects of consuming preloads with different macronutrient and energy contents on subsequent intake and subjective feelings of hunger and satiety in children, young adults and the elderly. SUBJECTS: 30 Children (4-6 y), 33 young adults (18-26 y) and 24 elderly (61-86 y). DESIGN: A 'preload test meal' design was applied. Subjects were given four different strawberry yoghurt preloads that varied in energy and macronutrient content, or no yoghurt. Children, young adults and elderly consumed 200, 340 and 300 g of the preload, respectively. One yoghurt was low-fat, low-carbohydrate and low in energy (the control; 0.7 MJ/500 g serving), one yoghurt was high-fat and medium in energy (71% of energy (en%) of fat; 2 MJ/500 g serving), one yoghurt was high-carbohydrate and medium in energy (87 en% of carbohydrate; 2 MJ/500 g serving) and the fourth yoghurt was high-fat and high-carbohydrate and high in energy (42 en% of fat and 53 en% of carbohydrate; 3 MJ/500 g serving). Ninety minutes after preload consumption, subjects had an attractive ad libitum lunch-buffet. Energy intake at lunch and subjective feelings of hunger and satiety were analysed. RESULTS: The ability to compensate at lunch did not differ among the three age groups. Compared to the no-preload condition, all children, young adults and elderly ate significantly less after the high-fat and high-carbohydrate yoghurt. The energy compensation observed in the children ranged between -21% and 34%, in the young adults between 15% and 44% and in the elderly between 17% and 23%. Hunger responses were clearly different between young adults and the elderly. Compared to the no-preload condition, the young adults showed larger differences in their appetite ratings than the elderly, indicating that the elderly were less sensitive to the energy content of the preload than the young adults. CONCLUSION: We conclude that the ability to regulate the food intake within a preload 90 min test meal paradigm did not differ among children, young adults and the elderly. Sponsorship: This study was funded by the European Commission as part of project FAIR-CT95-0574.     

Rice-based oral rehydration solution decreases the stool volume in acute diarrhoea

A ramdomized trial using oral rehydration solutions (ORS) with rice or glucose was carried out in 342 patients with acute watery diarrhea in the outpatient ward of the International Centre for Diarrheal Disease Research, Bangladesh, during an epidemic of cholera between December 1982-March 1983. On admission, 75% of these patients had severe dehydration and 70% were positive for Vibrio cholerae. There were 185 children aged under 10 years and 157 adults; 169 patients were treated with rice-ORS and 173 with glucose-ORS. Patients in both groups were comparable in age and body weight as well as the duration and severity of illness. Patients with severe dehydration were first rehydrated intravenously, and then treated with ORS. Those with moderate dehydration received ORS from the start. The mean stool output in the first 24 hours in children treated with rice-ORS was less than that in those treated with glucose-ORS (155 vs 204 ml/kg 24h; P0.01). The same was the case for the adult patients, the corresponding values for stool output being 115 versus 159 ml/kg24h (P0.05); the corresponding intakes in adult patients were, respectively, 180.5 and 247 ml/kg24 hours. A gain of about 10% of the body weight on admission was observed in all the groups. 6 cases (4 children and 2 adults) who failed to respond to oral rehydration after intravenous therapy all belonged to the glucose-ORS group. The study shows that, even under epidemic conditions of severe cholera or in cholera-like diarrhea, the glucose or sucrose solutions can be replaced by rice powder with improved results. Glucose and sucrose are manufactured products which are expensive and not always available in countries where diarrheal diseases are a problem. Rice, a staple food in many of these countries, reduces the fluid requirements when used in ORS and also provides increased nutrition even in the acute stage of illness.     

Drinking water source, diarrheal morbidity, and child growth in villages with both traditional and improved water supplies in rural Lesotho, southern Africa.

This study examined the growth and morbidity rates of young children in relation to exclusive and non-exclusive use of improved water supplies in rural Lesotho, southern Africa. Data were collected for 247 children 60 months of age and under between July 1984 and February 1985 in 10 villages that had an improved water supply at least one year prior to investigation. Children whose families relied exclusively on the new water supply for their drinking and cooking needs grew 0.438 cm and 235 g more in six months than children whose families supplemented the new water supply with the use of contaminated traditional water for drinking and cooking. The difference in growth was greater among children over 12 months of age at the start of the evaluation than among infants. This may be explained partly by lower rates for Giardia lamblia, the most commonly identified pathogen in stools in older children. Among infants, similar rates of Campylobacter, the most commonly isolated pathogen among infants, may have prevented larger differences. Results suggest that improved drinking water supplies can benefit preschool children's health after infancy, but only if they are functioning and utilized exclusively for drinking and cooking purposes.     

Hydration and health: a review

Water is essential for life and maintaining optimal levels of hydration is important for humans to function well. Water makes up a large proportion of our body weight (60% on average), distributed between the intracellular (inside cells) and extracellular (water in the blood and in between cells) compartments. Water is the major component of body fluids, such as blood, synovial fluid (fluid in the joints), saliva and urine, which perform vital functions in the body. The concentration of solutes (osmolality) in body fluids is closely controlled, and even very small changes in osmolality trigger a physiological response; either to increase body water by reducing urinary output and stimulating thirst; or to excrete excess water as urine. Generally, body water is maintained within narrow limits. However, if water losses are not sufficiently replaced, dehydration occurs. Extreme dehydration is very serious and can be fatal. More mild dehydration (about 2% loss of body weight) can result in headaches, fatigue and reduced physical and mental performance. It is also possible to consume too much water and in rare cases this can result in hyponatraemia (low levels of sodium in the blood). We can get water from almost all drinks and from some foods in the diet. Food provides about 20% on average and this could vary widely depending on the types of food chosen. We also get water from all the drinks we consume, with the exception of stronger alcoholic drinks like wines and spirits. All these can contribute to dietary water, but also have other effects on health both positive and negative. The major concerns with regards to beverages are their energy content and their effect on dental health. With obesity levels continuing to increase it is important for many in the population to control their energy intake, and drinks as well as foods must be considered for their energy content. With regards to dental health, there are two concerns; dental caries and dental erosion. Dental caries are caused by a reduction in pH due to bacterial fermentation of carbohydrates, and so the frequency of consumption of drinks containing sugars is a concern for risk of caries. Dental erosion occurs at a lower pH and is caused by the consumption of acidic foods and drinks, in particular, citrus juices and soft drinks containing acids. Individual water needs vary widely depending on many factors including body size and composition, the environment and levels of physical activity. Thus it is very difficult to make generic recommendations about the amount of water to consume. The FSA currently recommends drinking about 1.2 litres per day (about 6–8 glasses).