Eating and drinking at night – the effect on the health of small children

How much sleep does a child need?

Observational studies of normal sleep patterns in a large child population from many countries show that, on average, over a 24-hour period, children sleep:¹

• 0–12 months: 12.8 hours
• 1–6 years: 11.9 hours
• 6–12 years: 9.2 hours

But the length of time children sleep varies around the world; children in all age groups in Asia sleep 60–120 minutes less every day compared with children in Europe and 40–60 minutes less than children in the USA.² The length of time children sleep appears to have reduced over a long historical period. An overview for the years 1897 to 2009 shows that the total time children spend sleeping per day has reduced by just over an hour in most of the countries studied.³

One reason for the reduction in sleep among infants could be uncertainty over the interplay between parents and children and the parents’ roles as carers. Overstimulation, too much attention and feeding in situations where the child should have been soothed and reassured using some other kind of feedback may form part of a vicious circle associated with awakening and being fed several times a night.⁴

How do nocturnal meals affect the child’s health?

Eating many times at night is associated with an increased risk of caries. Caries occurs when bacteria in the mouth ferments carbohydrates to form acid. The acid attacks the dental enamel so that mineral dissolves.^5,6 This demineralization of the dental enamel may be balanced by a healing process, a remineralization. This also occurs by means of the buffering properties of the saliva and is reinforced and accelerated by fluoride. The bacteria that often occurs in connection with an incipient attack of caries is also found in the coatings of the tooth surfaces and establishes itself more easily if there is a high supply of sugar.⁵ The bacteria are transferred from individual to individual, for example, from parent to child when a parent puts a pacifier or feeding bottle into their own mouth before giving it to the child. 

Another great risk factor is sweetened drinks in the feeding bottle at night. Swedish research shows that all children who have been given sweetened drinks at night at 1 or 2 years of age had cavities in their teeth by the age of 3. In addition, all children who developed caries at the age of 1 had either been given fruit syrup, juice or rose hip soup to drink at night.⁷ Feeding with a bottle containing infant formula at night leads to an increased risk of caries compared with breastfeeding at night.^8,9 Calcium and phosphorus from the breast milk is deposited directly onto the dental enamel in turn remineralizing them. In children up to one year of age, no link is seen between breastfeeding and an increased risk of caries, instead breastfeeding appears to protect against caries. After the age of one this protection is gradually reduced.^10,11 But children who are breastfed often and for a long period of time have an increased risk of caries, particularly if their teeth are not brushed.¹²

In addition to caries, there are also other risks associated with children awakening at night; sleep is important for a child to develop normally. A lack of sleep and other sleep disorders are associated with various health problems in children. Too little sleep is a contributing factor to children becoming overweight; the connection is clearest among children in the ages of 1 to 6 where a lack of sleep also predisposes a child to becoming overweight in the longer term.¹³ From 9 months of age, it is recommended that children should sleep ‘through the night’. This does not mean however that the child needs to sleep for 10–12 hours at a time but that the child sleeps without being awoken for meals for five hours, for example, from around midnight to 5 o’clock.¹⁴

What can you do to prevent ill-health?

To begin with, it is important to remind the parents that a child’s sleep cycles are much shorter than adults’, which means that waking up at night, even if this is tiresome, is entirely natural for the child due the child’s cycles between depth of sleep. To make things easier for the entire family, the parents can attempt to teach the child to go back to sleep by himself or herself at least after some of these awakenings. In order to be able to do so, the children need to learn to put themselves to sleep in the evening. From about 4 months of age, a recurring and calming evening routine can be introduced at bedtime, with the parents gently reducing any help in falling asleep.⁶ The procedure for falling asleep helps the child to become aware of and understand what is coming. A regular dietary regime during the day also helps the child to feel hunger at approximately the same times every day, which can also reduce wakening up for food at night. In order to fit in more meals during the day, the time between meals should not be too long because then the child’s feelings of hunger may abate, but not so short either that the child never gets the chance to feel hunger. Some brief advice for parents is to make both feeding times and sleeping times safe and cosy experiences for the child and to introduce teeth-brushing with fluoride toothpaste when the first tooth arrives.

¹Galland, B. C., Taylor, B. J., Elder, D.E., & Herbison, P. (2012). Normal sleep patterns in infants and children: a systematic review of observational studies. Sleep Med Rev, 16, pp.213–222.
²Olds, T., Blunden, S., Petkov, J., & Forchino, F. (2010). The relationships between sex, age, geography and time in bed in adolescents: a meta-analysis of data from 23 countries. Sleep Med Rev, 14, pp.371–8. 
3Matricciani, L., Olds, T., & Petkov, J. (2012). In search of lost sleep: secular trends in the sleep time of school-aged children and adolescents. Sleep Med Rev, 16, pp.203–211. 
⁴Hägglöf, B. (2015) Sleep problems in children – historical and contemporary aspects [Sömnproblem hos barn – historiska och nutida aspekter]. Uppsala: Swedish National Food Administration. 
⁵Kylberg, E., Westlund, A. M., & Zwedberg S. (2014). Breastfeeding today [Amning i dag]. Gothia: Stockholm. 
⁶Magnusson, M., Blennow, M., Hagelin, E., & Sundelin C. (2016). Paediatric healthcare today [Barnhälsovård idag]. Liber: Stockholm. 
⁷Wendt, L. K. (1995). On oral health in infants and toddlers. (Thesis, University of Gothenburg, 1995). 
⁸Mohebbi, S. Z., Virtanen, J. I., Vahid-Golpayegani, M., & Vehkalahti, M. M. (2008). Feeding habits as determinants of early childhood caries in population where prolonged breastfeeding is the norm. Community Dent Oral Epidemiol, 36(4), pp.363-369. 
⁹Peres, R. C. R., Coppi, L. C., Volpato, M. C., Groppo, F. C., Cury, J. A., Rosalen, P. L. (2008). Cariogenic potential of cows', human and infant formula milks and effect of fluoride supplementation. British Journal of Nutrition, Vol.101(3), pp.376-382 
¹⁰Dye, B. A., Shenkin, J. D., Ogden, C. L., Marshall, T. A., Levy, S. M., & Kanellis, M. J. (2004). The relationship between healthful eating practices and dental caries in children aged 2-5 years in the United States, 1988-1994. J Am Dent Assoc, 135(1), pp.55-66. 
¹¹Ribero, N. M., & Ribero, M.A. (2004). Breastfeeding and early childhood caries: a critical review. J Pediatr (Rio), 80 (5 Suppl), pp.199-210.
¹²White, W. (2008). Breastfeeding and the risk of early childhood caries. Evid Based Dent, 9, pp.86-88. 
¹³Taheri, S. (2006). The link between short sleep duration and obesity: We should recommend more sleep to prevent obesity. Archives of Disease in Childhood, 91.(11), pp.881-884. 
¹⁴Smedje, H. (2015). Classification of sleep disorders in children [Klassifikation av sömnstörningar hos barn]. Uppsala: Swedish National Food Administration.