Bone, vitamin D supplements, and sunlight By Marc Sorenson, EdD.
Bone and vitamin D are connected, yet, it may not be in the way you think. It is probably common knowledge that vitamin D is necessary for bone strength, particularly rickets. Yet, beyond rickets, it is not settled science that supplements significantly improve bone strength.
Proving the point regarding supplements and bone strength.
To prove this point, and to cause thoughtful consideration, I call your attention to a meta-analysis of 23 studies. The research assessed change in bone density (BD) from measurement inception to completion of each experiment. The bone densities measured the lumbar spine, femoral neck, total hip, trochanter, total body, or forearm. In addition, all participants took vitamin D supplements. There was little observable change in BD, so the results were disappointing. Thus, the researchers reported, in conclusion, “Continuing widespread use of vitamin D for osteoporosis prevention in community-dwelling adults without specific risk factors for vitamin D deficiency seems to be inappropriate.” Yet, before you give up on vitamin D for bone, let us consider the weakness of the research.
Does bone require much more than 800 IU per day to increase bone strength?
In 10 of the 23 studies cited above, the vitamin D dosage was less than 800 IU per day. This is rather like throwing a packet of food coloring into the sea and expecting the sea to turn red. Direct full-body sunlight during 10-15 minutes can stimulate the skin to produce up to 20,000 IU of vitamin D. Sunlight is the natural way to obtain vitamin D and numerous other healthful photoproducts. A minuscule dose of 800 IU will probably do little for bone strength. Yet, if the researchers had found studies using 3,000 and 5,000 IU, I could have more easily believed their conclusions. However, I could easily have been wrong, as you will see.
So are there other studies that make contradictory conclusions?
No. Most of the research using high-dose vitamin D supplements also had poor results. They usually resulted in much higher fracture risk for those taking the supplements. This was especially true in those who took large, intermittent doses and or intermittent intramuscular injections. Other data showed that doses of more than 4,000 IU daily are associated with more falls and fractures. In addition, research from the Journal of the American Medical Association showed an alarming trend. First of all, treatment with vitamin D for 3 years (4000 IU) day was counterproductive. Thus, it resulted in statistically significant lower bone mineral density (BMD) in certain bones. Furthermore, the same was true for 10,000 IU per day.
Are there better ways to keep bone strong?
Another factor to consider: vitamin D supplements may not be the same as vitamin D made by the human body. The skin always makes natural vitamin D for humans during exposure to sunlight and other sources of UVB light. Irradiating sheep’s lanolin produces the Vitamin D for supplements. Therefore, although 20,000 IU of vitamin D in 20 minutes is possible from sun exposure, the results are very different. Skin-produced vitamin D from sun exposure does not result in increased fracture risk and lower BMD.
The Spanish Study: an eye-opener
An important study from Spain shows that those who actively sought sun exposure had only 1/11 the risk of hip fracture compared to those who were not sun seekers! In this case, the sun-seeking people must have produced remarkable quantities of vitamin D. They also they increased bone strength remarkably. In addition, we know that the high vitamin D levels certainly caused no problem with bone density and bone strength! How can this be if high doses of vitamin D supplements lead to increased fracture rates? The difference, in my opinion, is the source.
Lessons learned, and conclusions
Therefore, we may take away important lessons from this treatise. First, vitamin D produced by sunlight is not the same as vitamin D from a pill. Moreover, vitamin D is a primary photoproduct of sun exposure. There is an exceptional difference between a pill produced from lanolin and a photoproduct produced in response to sunlight. If sun exposure can produce up to 20,000 IU of vitamin D, and it increases bone strength, something is awry with vitamin supplements, which decrease bone strength. We have produced evidence that show vitamin D supplements may increase bone fragility. It is time to accept the sun or other source of light as the major source of bone strength. That other source could be sunlamps or tanning beds.
A synopsis on bone and sunlight
Finally, we must realize that sun exposure produces many photoproducts beyond vitamin D. Serotonin, endorphin, nitric oxide; brain-derived-neurotropic factor (BDNF) and dopamine are some of those photoproducts. All of them are vital to human health. Who is to say that these photoproducts do not form a synergistic relationship with sun-produced vitamin D to create the miracle of hip-fracture reduction? Do not neglect your regular, non-burning sun exposure. It may save your bones and your life.