Melk en botten?*

De kritikasters rond melk krijgen wellicht iets meer gelijk.

Uit een analyse van 58 studies over melk en de calcium uit de melk in relatie tot botopbouw bij mensen tot 25 jaar blijkt slechts uit 9 studies een (nogal) mager positief effect. Er is geen enkel verschil te zien  bij consumpties van 1 of 3 tot 4 glazen melk per dag. Dat melk de beste bron van calcium en goed voor de botten zou zijn is dus niet juist. Behalve in melkproducten zit er ook calcium in groene  groentes,  bepaalde vissoorten, noten en sojamelk. Belangrijk voor goede botopbouw is voldoende bewegen in de buitenlucht en gezonde voeding

At stake are the diets of millions of American children. Should they get their calcium by consuming as many as three servings of dairy products a day, as the federal government now suggests? The milk skeptics are still a minority view among nutritionists. But the new article, in the March issue of Pediatrics, gave them a powerful platform.

The authors analyzed findings from 27 studies focused on diet and bone health in children and young adults. According to the authors, only nine of those studies found a relationship between calcium intake and bone health, and the effects were small.

"We didn't see any difference between kids who are consuming around 500 milligrams (of calcium) and those consuming 800 or 1200," said study co-author Amy Lanou, nutrition director for the Physicians Committee for Responsible Medicine.

About a glass-and-a-half of milk would provide 500 milligrams of calcium, Lanou said, but she recommends non-animal sources of calcium instead, such as dark greens, tofu, nuts and seeds, and calcium-fortified products such as rice milk and soy milk.

Getting more calcium from dairy products simply isn't necessary, she said. "The bottom line for parents is that if your child is lactose-intolerant, or if your child doesn't like milk or is allergic to milk, you really don't have to worry," she said.

Instead, she suggests that parents look at other ways to promote the growth of strong bones. "The best option is to get your kids outside playing, getting some exercise and some sunshine, and make sure they have an overall healthy diet rich in fruits, vegetables, grains and legumes."

Calcium, Dairy Products, and Bone Health in Children and Young Adults: A Reevaluation of the Evidence

Objective. Numerous nutrition policy statements recommend the consumption of 800 to 1500 mg of calcium largely from dairy products for osteoporosis prevention; however, the findings of epidemiologic and prospective studies have raised questions about the efficacy of the use of dairy products for the promotion of bone health. The objective of this study was to review existing literature on the effects of dairy products and total dietary calcium on bone integrity in children and young adults to assess whether evidence supports (1) current recommended calcium intake levels and (2) the suggestion that dairy products are better for promoting bone integrity than other calcium-containing food sources or supplements.

Methods. A Medline (National Library of Medicine, Bethesda, MD) search was conducted for studies published on the relationship between milk, dairy products, or calcium intake and bone mineralization or fracture risk in children and young adults (1–25 years). This search yielded 58 studies: 22 cross-sectional studies; 13 retrospective studies; 10 longitudinal prospective studies; and 13 randomized, controlled trials.

Results. Eleven of the studies did not control for weight, pubertal status, and exercise and were excluded. Ten studies were randomized, controlled trials of supplemental calcium, 9 of which showed modest positive benefits on bone mineralization in children and adolescents. Of the remaining 37 studies of dairy or unsupplemented dietary calcium intake, 27 studies found no relationship between dairy or dietary calcium intake and measures of bone health. In the remaining 9 reports, the effects on bone health are small and 3 were confounded by vitamin D intake from milk fortified with vitamin D. Therefore, in clinical, longitudinal, retrospective, and cross-sectional studies, neither increased consumption of dairy products, specifically, nor total dietary calcium consumption has shown even a modestly consistent benefit for child or young adult bone health.

Conclusion. Scant evidence supports nutrition guidelines focused specifically on increasing milk or other dairy product intake for promoting child and adolescent bone mineralization.

  (Maart 2005) (Opm. Ook een goed alternatief voor melk kan yoghurt en kwark zijn. Dit zijn ook calciumrijke melkproducten waar doorgaans positief over gesproken wordt. )

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