There are two major factors known to contribute to osteoporosis -- peak bone mass during childhood and adolescence and the rate of bone loss during aging. Bone mineral density (BMD) and bone mineral apparent density (BMAD) are used as measures of osteoporosis and are the result of the process of bone formation and resorption. Bone mass accumulates during childhood and early adulthood and it is thought that during this time increased bone resorption and decreased bone formation can reduce peak bone mass. Therefore, it is important to identify contributors to skeletal development in order to prevent osteoporosis.

One such contributor may be Vitamin D, which can be obtained through diet or synthesized in the skin after sun exposure. Vitamin D is commonly measured by serum concentration of 25-hydroxyvitamin D (25(OH)D). Vitamin D deficiency is common among children and adolescents, especially when sunshine is scarce during the winter months. This can lead to severe hypovitaminosis D.

A recent study, which investigated the effects of vitamin D status on the acquisition of BMD and BMAD, found a significant association between the baseline concentration of 25(OH)D and BMD and BMAD at the lumbar spine and femoral neck among peripubertal girls. Girls with the highest baseline serum 25(OH)D, had a BMD that increased 26 percent more than girls with the lowest baseline serums; that of BMAD increased some 50 percent. Participants whose baseline serum 25(OH)D was greater than 50 nmol/L did not lose BMD at the lumbar spine, indicating that adequate vitamin D is important during this phase of life, according to researchers.

Researchers note that dietary intake of vitamin D is not enough to maintain optimal vitamin D levels during the winter months. In an unrelated study, it was found that participants had less than optimal vitamin D levels even during the summer months, when sun exposure is generally greater.

The study suggests that hypovitaminosis D during the pubertal stages of life, when the growth of BMD is most rapid, is more harmful than hypovitaminosis D at an earlier age. Researchers believe that the later premenarcheal years are a crucial stage in preventing osteoporosis.

Researchers believe that the effect of vitamin D may be specific to certain areas, as results showed a particular effect on the lumbar spine. A previous study found that exposure to sunlight effected BMD in prepubertal girls, with a more pronounced effect at the spine than hip. Further evidence of site specific effects were shown by another study that found an association between BMD of the forearm and hypovitaminosis D in adolescents.

Participants in the original study had generally low dietary vitamin D intakes and low serum 25(OH)D values at the beginning of the three-year study. They were given vitamin D supplements during the winter, however, this had little effect on 25(OH)D concentration.

Physical activity has been shown to have a strong effect on the growing skeleton. To account for this, researchers adjusted BMD and BMAD values for baseline bone density and amount of physical activity over the three-year period.

Researchers concluded that hypovitaminosis D has harmful effects on bone mineral growth, particularly at the lumbar spine, during a period of development when peak bone mass should be reached. They say that vitamin D supplements should be considered during the peripubertal years.

American Journal Clinical Nutrition December 2002 76:1446-1453

Dr. Mercola's Comments:

Further evidence of the central importance of making certain that your child gets enough vitamin D in the winter. If you live in the U.S., you can be virtually assured that your child is not getting enough vitamin D from the sun right now. To solve this, you can give them cod liver oil as it has the type of vitamin D that can safely increase the vitamin D level to one that will help build strong bones in your child’s body. The dose is one teaspoon for every 50 pounds of body weight. The cod liver oil does not have to be consumed on a spoon, it is far better tolerated if it is poured over vegetables, similarly to how you would use olive oil as a salad dressing. The key to remember here is that cod liver oil is very perishable and should not be poured over hot food or cooked with. When you give your child cod liver oil you will also be supplying them with essential omega-3 fats that will maximize their brain development and help prevent ADHD. Please remember that the quality of the cod liver oil is very important, as a high quality oil will be purified of mercury and other toxins. I recommend Carlson’s brand cod liver oil, which I have found to be of superior quality. If you cannot find it at your local health food store, you can purchase Carlson’s cod liver oil conveniently in our online store. Related Articles: Test Values and Treatment for Vitamin D Deficiency