Obese do not process vitamin D from sunlight as well as lean individuals

August 27, 2000

Vitamin D deficiency is a common problem which, left untreated, can lead to bone disorders such as rickets in children and bone fractures in adults. In an article published in The American Journal of Clinical Nutrition, Wortsman et al. present research results on the bioavailability of vitamin D through different routes of administration in obese and lean individuals. Study subjects were first exposed to simulated sunlight to stimulate production of vitamin D in the skin, and one month later were administered oral doses of vitamin D. In the obese subjects oral vitamin D was more bioavailable than vitamin D from sunlight exposure, suggesting that the obese individuals did not process vitamin D from sunlight as well as the nonobese. The authors propose that vitamin D is being sequestered in body fat in obese persons, giving rise to a relative deficiency which could be corrected with oral administration of extra vitamin D.

The study was conducted during the winter months using two groups of 19 healthy white subjects, one lean and one obese. All were exposed to whole-body irradiation in a phototherapy unit (tanning bed), and follow-up blood samples were obtained to ascertain serum vitamin D levels. One month later the subjects were challenged with an oral dose of 50 000 IU of vitamin D, and follow-up blood samples again obtained. Obese individuals showed an attenuated response to simulated sunlight, with serum vitamin D concentrations less than half those of the lean individuals after irradiation. Both groups had the same initial rise in levels of the steroid precursor vitamin D3 in the skin, but in the obese subjects less vitamin D3 was released from the skin into the circulation. Oral administration of vitamin D2 -the synthetic form of the vitamin used for supplementation -- resulted in serum concentrations that were not significantly different between the two groups. The authors hypothesized that oral vitamin D2 was more bioavailable than vitamin D3 synthesized in the skin in the obese. Additional in vitro studies on vitamin D production in skin cells procured during surgery from obese and nonobese subjects were performed. Both, when exposed to sunlight, were equally efficient in the production of the precursor vitamin D3.

In their conclusion the authors state that most humans derive their vitamin D requirement from casual exposure to sunlight, and that obese individuals appear to have > 50% lower bioavailability of vitamin D from cutaneously synthesized vitamin D3. Thus, the more accessible oral form should be relied upon to correct vitamin D deficiency associated with obesity.
-end-
Wortsman, Jacobo et al. Decreased bioavailability of vitamin D in obesity. Am J Clin Nut 2000;72:690-693.

For more information please contact: Dr. M F Holick at mfholick@bu.edu

This media release is provided by The American Society for Clinical Nutrition, to provide current information on nutrition-related research. This information should not be construed as medical advice. If you have a medical concern, consult your doctor.

To see the complete text of this article, please go to: http://www.faseb.org/ascn/temp/ajcn/September/690-693-holick.pdf




American Journal of Clinical Nutrition

Related Obese Articles from Brightsurf:

Non-obese Vietnamese Americans are 60% more likely to have diabetes
A new study has found that Vietnamese-American adults who were not obese were 60% more likely to have diabetes than non-obese, non-Hispanic, White Americans, after accounting for age, sex, sociodemographic factors, smoking history and exercise level.

Depression in adults who are overweight or obese
In an analysis of primary care records of 519,513 UK adults who were overweight or obese between 2000-2016 and followed up until 2019, the incidence of new cases of depression was 92 per 10,000 people per year.

Cellular stress makes obese mothers have obese babies
Maternal obesity increases the risk for obesity and metabolic perturbations in their offspring, but what are the mechanisms?

Truckies more obese than most: QUT study
More than 200,000 people are employed as truck drivers in Australia and while their role in transporting goods across its wide brown land is critical, they are among the nation's most unhealthy.

These gut bacteria prevent mice from becoming obese -- what could that mean for us?
A specific class of bacteria from the gut prevents mice from becoming obese, suggesting these same microbes may similarly control weight in people, a new study reports.

Obese people outnumber smokers two to one
New figures from Cancer Research UK show that people who are obese now outnumber people who smoke two to one in the UK, and excess weight causes more cases of certain cancers than smoking, as the charity urges government action to tackle obesity.

'Strongest evidence yet' that being obese causes depression
New research released today from the University of South Australia and University of Exeter in the UK has found the strongest evidence yet that obesity causes depression, even in the absence of other health problems.

Unlike obese adults, obese children don't have more pain after surgery
While obese adults often report more pain after surgery, the same does not appear to be true for obese children, according to the largest study of its kind, being presented at the ANESTHESIOLOGY® 2018 annual meeting.

People with asthma at higher risk of becoming obese
Obesity is known to be a risk factor for developing asthma but a new study shows that the reverse is also true: people with asthma are more likely to go on to become obese.

Can you really be obese yet healthy?
A new paper has called for an end to the term 'healthy obesity,' due to it being misleading and flawed.

Read More: Obese News and Obese Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.