No. 9, August 1991
1. Exclusive breast-feeding in early infancy: prevalence
Studies of feeding practices during the first year of life indicate that 98% of the infants born in Africa, 96% of those born in Asia, and 90% of those born in South America are breast-fed for some part of this period. The period of exclusive breast-feeding, however, is usually short. Even in countries where infants are traditionally breast-fed over a long period, such as Indonesia, Kenya, Peru, and the Philippines, supplementary fluids are given already in the first few weeks of life. In Peru, for example, it was shown that although 99% of infants were breast-fed, in the first month of life 83~c of them received water or teas in addition to breast milk.
2. Risks associated with supplementary intake of water and/or teas in early infancy
The importance of breast-feeding in the prevention of diarrhoea has been demonstrated in several studies. The protection is greatest among infants who are exclusively breast-fed. Recent research has demonstrated that giving young infants supplementary fluids such as water and/or teas in addition to breast milk is associated with a significant increase in the risk of diarrhoeal disease. In a study conducted in a poor urban community in Lima, Peru, the incidence and prevalence rates of diarrhoea in infants younger than 6 months were significantly higher among those who received water and teas in addition to breast milk than among those who were exclusively breast-fed. The diarrhoea prevalence rates doubled with the addition of these supplementary fluids. A case-control study of infant mortality in Brazil showed that infants who received water, tea, or juice in addition to breast milk were at increased risk of diarrhoeal death. Each additional feed with these fluids substantially increased the risk of death.
Young infants who receive these supplementary fluids have a lower intake of breast milk than if they are exclusively breast-fed and are also more likely to be breast-fed for shorter periods. In Brazil, for example, infants who were offered water and teas in addition to breast milk in the first days of life were twice as likelv to stop breast-feeding before the age of 3 months as those who were exclusively breast-fed.
3. Fluid requirements during the first 6 months of life
The average daily fluid requirement of a healthy infant ranges from 80-100 ml/kg in the first week of life to 140-160 ml/kg between 3 and 6 months, depending on the concentration of the feeds, energy consumption, and environmental humidity and temperature. Consumption below the required level will lead to dehydration, with increases in serum and urine osmolarity.
With the low concentrations of sodium, chloride, potassium, and nitrogen in breast milk, only a relatively small amount of the fluid intake is needed for excretion of resulting waste products. Calculations indicate that healthy-infants who consume enough breast milk to satisfy their energy needs receive, with a considerable safety margin, enough fluid to satisfy their fluid requirements, even in hot and dry environments.
To check the validity of these calculations, six studies were performed in settings with a high environmental temperature and varying degrees of humidity to measure the urine osmolarity values of healthy, exclusively breast-fed infants. The studies are summarized in the Table.
Even the still immature kidney of a very young infant can achieve a urine concentration of 700 mOsmll, and healthy infants can attain a concentration of up to 1200 mOsm/l by the age of 3 months. Out of more than 213 samples that were examined. over 90% had an osmolarity that was well below these levels, indicating the absence of dehydration. Only in 14 samples did urine osmolarity exceed 700 mOsm/l. Of these, all but two, which came from children who were nevertheless considered to be in adequate water balance (Almroth & Bidinger, 1990), had an osmolarity below 1200 mOsm/l. These results support the theoretical calculations: osmolaritv values were maintained well within the normal concentration capacity of the kidney even under extremely hot and dry conditions.
Supplementation in the form of water and teas in early infancy is a
common practice and one that is associated with significantly increased
risks of diarrhoea morbidity and mortality. On both theoretical and empirical
grounds it is concluded that these supplementary fluids are not needed
to maintain water balance in healthy infants younger than 6 months who
are exclusively breast-fed. Their use should therefore be actively discouraged,
and exclusive breast-feeding should be promoted as the ideal feeding practice
during the first 4 to 6 months of life.
Summary of studies on the water requirements of exclusively breast-fed infants:
|Country||Year||Temperature °C||Relative humidity||Number of infants||Age (months)||Number of samples||Urine osmola rity (mOsm/l)|
|Argentina a||1979||20-39||60-80||8||< 1-2||24||105 - 199|
|Israel b||1983||32-37||13-41||15||1-5||15*||55 - 320|
|India d||1991||34-41||9-75||23||14||23#||99 - 703|
|Jamaica e||1978||24-28||62-90||16||< 14||48||103 - 468|
|Peru f||1986||24-30||45-96||40||<1-6||40#||30 - 544|
a Armelini, PA & Gonzalez, CF. Breast-feeding and fluid intake in a hot climate. Clinical Pediatrics, 18: 425-426, 1979.
b Goldberg, NM & Adams E. Supplementary water for breast-fed babies in a hot and dry climate - not really a necessity. Archives of Diseases in Childhood, 58: 73-74, 1983.
c Almroth, S & Bidinger, PD. No need for water supplementation for exclusively breast-fed infants under hot and arid conditions. Transactions of the Royal Society of Tropical Medicine and Hygiene, 84: 602-604, 1990.
d Sachdev, HPS et al. Water supplementation in exclusively breastfed infants during summer in the tropics. Lancet, 337: 929-933, 1991.
e Almroth, SG. Water requirements of breastfed infants in à hot climate. American Journal of Clinical Nutrition, 31: 1154-1157, 1978.
f Brown, KH et al. Milk consumption and hydration status of exclusively breast-fed infants in a warm climate. Journal of Pediatrics, 108: 677-680, 1986.
For further information, contact:
The Director, Division of Diarrhoeal and Acute Respiratory Disease Control
World Health Organization, 1211 Geneva 27, Switzerland
Tel: +41 22 791-2632, Fax: +41 22 791-4853,