Meta-regression analysis indicated that milk might have more effect on growth than other dairy products while lower height-for-age and being a teenager increased the effect of supplementation .
In conclusion , there is moderate quality evidence that dairy products supplementation  stimulate linear growth supporting hypotheses that changing levels of consumption of dairy products in the 19th and 20th centuries contributed to trends in height
The positive relationship between per capita availability of dairy products and average  height  found in historical studies ( for instance in nineteenth century Bavaria , Prussia and France ; Baten , 2009 ) does not necessarily indicate a causal relationship .
Historical studies usually apply non-experimental methods that may produce substantial bias .
Modern experimental controlled studies may provide high quality evidence supporting a causal relationship between consumption of dairy products and physical growth .
This paper provides a systematic review and meta- analysis of controlled trials investigating the effect of supplementing usual diet with dairy products on physical growth .
A randomised controlled trial of the effect of the provision of free school milk on the growth of children.
A r and omised controlled study was carried out of the effect on growth of the provision of free milk supplements to schoolchildren aged 7 and 8 . In selecting children for this study , the aim was to identify those whose socioeconomic circumstances might place them at a disadvantage for growth . Five hundred and eighty-one-children were selected from schools where a high proportion of the pupils received free school meals , and from families with four or more children . The subjects were r and omly allocated to receive a third of a pint ( 190 ml ) of free milk daily for six school terms or to a control group . The mean difference in height gain at the end of twenty-one- and -a-half months was 3 % or 2.93 mm ( P less than 0.05 ) in favour of the children provided with free milk . The mean difference in weight gain was 130 g ( P greater than 0.05 ) in their favour . The height and weight gain associated with the provision of free mild was very small in the study population , and it is therefore likely that the benefit to growth of providing free milk for the whole unselected population of schoolchildren of these ages would be even smaller
Meta-regression analysis indicated that milk might have more effect on growth than other dairy products while lower height-for-age and being a teenager increased the effect of supplementation .
In conclusion , there is moderate quality evidence that dairy products supplementation  stimulate linear growth supporting hypotheses that changing levels of consumption of dairy products in the 19th and 20th centuries contributed to trends in height
The positive relationship between per capita availability of dairy products and average  height  found in historical studies ( for instance in nineteenth century Bavaria , Prussia and France ; Baten , 2009 ) does not necessarily indicate a causal relationship .
Historical studies usually apply non-experimental methods that may produce substantial bias .
Modern experimental controlled studies may provide high quality evidence supporting a causal relationship between consumption of dairy products and physical growth .
This paper provides a systematic review and meta- analysis of controlled trials investigating the effect of supplementing usual diet with dairy products on physical growth .