According studies in both the United States and Denmark, drinking milk does make kids taller and bigger. Children who drink three or more servings of milk per day between the ages of 2 and 4 years seem to grow taller than those who do not. Excessive milk drinking in older children might increase their weight. One literature review adds that while adequate protein is needed for bone development, excess consumption can lead to calcium leaching.
Increase in Height
According to the study by The Royal Veterinary and Agricultural University in Denmark, "Cow's milk and linear growth in industrialized and developing countries," there is an association between drinking milk and height. The study indicated that milk "stimulates circulating insulin-like growth factor (IGF)-I, which suggests that at least part of the growth-stimulating effects of milk occur through the stimulation of IGFs." The study went on to say that in stunted children, the milk could have a positive effect, but that in well-nourished children the results are more complex.
Milk and BMI
A second study, "Dairy and milk consumption and child growth: Is BMI involved?" by the Department of Anthropology of the Indiana University in Bloomington examines the relationship between drinking milk and increase in body mass index (BMI). According to the article, the greatest increase in BMI was found in children between the ages of 2 and 4. The article adds that milk seemed to have a positive impact on BMI, a characteristic that was not shared by all milk products. Other milk products could include cheese, yogurt, custards, puddings and ice cream.
Allergies and Lactose Intolerance
Milk allergies are an abnormal response to ingesting milk, according to the Mayo Clinic. Symptoms occur shortly after drinking milk, and can include wheezing, indigestion, hives and, in severe cases, even anaphylaxis. Most children outgrow milk allergies by age 3. Lactose intolerance is the inability to digest certain milk sugars, according to WebMD. Symptoms include stomach bloating, abdominal pain, and possibly diarrhea. While less severe than an actual allergy, lactose intolerance can cause quite a bit of discomfort. It is more common in adults, but some children are lactose intolerant.
Concerns about Milk
As with many foods available in our supermarkets, some people have concerns about how our milk is produced, handled and marketed. An article from Weight Watchers, "Growth Hormones in Beef and Milk," explains that milk cows are sometimes injected with rBGH, a hormone that causes them to produce more milk. Weight Watchers reports that the Food and Drug Administration examined the milk from these cows and reported that it didn't affect the milk sold to consumers. However, an article entitled "5 Ways Milk Doesn't Do a Body Good," from "Week Magazine," comments that antibiotics can also appear in milk, and that it is high in sugars and fats.
According to "Calcium, Dairy Products, and Bone Health in Children and Young Adults: A Reevaluation of the Evidence," a media review published in a 2005 issue of "Pediatrics," a Medline search found few studies to support the emphasis placed on drinking milk to strengthen bones for children and adolescents. They comment that there are many dietary factors that influence absorption of calcium introduced through food sources, and that excess protein intake could actually leach calcium from bones during the digestion process. They end their commentary by noting that there have not been enough quality studies done to truly determine the impact of drinking milk on the growth of children and young adults.