Gut microbes may partner with a protein to regulate vitamin D

June 29, 2018 by Matt Swayne, Pennsylvania State University
"The changes in the microbiota might affect how much vitamin D a person can metabolize, or how the body metabolizes vitamin D, so there are implications, but it's still early and that remains to be seen," said Cantorna. Credit: iStock Photo / royaltystockphoto

A collection of bacteria in the gut may use a cell-signaling protein to help regulate vitamin D, a key nutrient that, among other benefits, is involved with building and maintaining bones, according to a team of researchers.

In a study on mice, researchers found that —a community of microorganisms in the gut that can help digest food and maintain immune function—may regulate the metabolism of endocrine vitamin D through a protein called fibroblast growth factor 23, or FGF 23, said Margherita T. Cantorna, distinguished professor of molecular immunology in Penn State's College of Agricultural Sciences. FGF 23 is a protein that sends signals to activate receptors located on the outside surface of cells.

Cantorna said it has been known that the amount of vitamin D in the gut can influence the microbiota.

"When you don't have enough vitamin D, the types of microbes in your gut change," said Cantorna. "Before we did this work, we started to think that this might be a two-way street and that the microbiota may also have an effect on how much vitamin D you had available and how it was utilized by a person."

The researchers used germ-free mice for the study. They measured the levels of different types of vitamin D in the mice at different times as the researchers introduced microbes into their systems during a two-week period.

According to the researchers, the germ-free mice began with low levels of three types of vitamin D—25hydroxy vitamin D, 24,25 dihydroxy vitamin D and 1,25 dihydroxy vitamin D—and with low levels of calcium and high levels of FGF 23 in the bloodstream. After the microbiota were introduced, the mice gradually reached normal vitamin D and calcium levels. The researchers also observed an initial drop in FGF 23 levels before vitamin D normalized.

The researchers, who reported their findings in a recent issue of Frontiers in Immunology, added that the length of time it took to reestablish vitamin D levels indicated that regulation was an indirect, multi-step process. It suggests that the microbiota does not work directly on increasing vitamin D levels, but instead may be inducing inflammation, which shuts off FGF23 and, in turn, causes a rise in vitamin D levels.

People can acquire vitamin D as part of their diet, often by consuming dairy products and through food fortified with the vitamin. Vitamin D can also be produced in the skin through exposure to ultraviolet light, usually sunlight.

Acquiring vitamin D through sunlight is problematic, however.

"The amount of vitamin D that you make in your skin with sunshine exposure is extremely variable," said Cantorna. "Obviously, you have to go out in the sun, so in some seasons you might not make any; darker skin makes less; and you make less as you age, so it's very difficult to regulate how much you're making in your skin. And there's also skin cancer. Really, for most people, the best way to get vitamin D is to eat it, or eat foods that are fortified with vitamin D."

Cantorna said that this is only a preliminary step and a lot of work must be completed before researchers can say conclusively whether the findings on the microbiota and vitamin D may apply to humans.

"The changes in the microbiota might affect how much vitamin D a person can metabolize, or how the body metabolizes D, so there are implications, but it's still early and that remains to be seen," said Cantorna.

Explore further: The dynamic duo: calcium and vitamin D

Related Stories

The dynamic duo: calcium and vitamin D

March 15, 2018
(HealthDay)—Your need for calcium gets a lot of attention, but your body can't use it without its partner, vitamin D, according to the American Academy of Orthopaedic Surgeons.

Low vitamin D levels if you're lactose intolerant

May 23, 2017
Those with a genetic intolerance to lactose may suffer from a vitamin D deficiency. That's according to a recent study conducted at the University of Toronto and published in the Journal of Nutrition.

Vitamin D deficiency may compromise immune function

February 25, 2014
Older individuals who are vitamin D deficient also tend to have compromised immune function, according to new research accepted for publication in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).

Low vitamin D linked to dry eye syndromes

February 10, 2016
(HealthDay)—Vitamin D deficiency is associated with dry eye and impaired tear function, according to a study published in the January issue of the International Journal of Rheumatic Diseases.

Certain factors affect vitamin D levels in children with chronic kidney disease

June 16, 2016
Researchers have identified certain modifiable and non-modifiable factors associated with vitamin D deficiency in children with chronic kidney disease (CKD). The findings, which appear in an upcoming issue of the Clinical ...

Low levels of vitamin D are associated with mortality in older adults

October 2, 2012
Low levels of vitamin D and high levels of parathyroid hormone are associated with increased mortality in African American and Caucasian older adults, according to a new study accepted for publication in The Endocrine Society's ...

Recommended for you

Like shark attack and the lottery, unconscious bias influences cancer screening

August 17, 2018
What do shark attack, the lottery and ovarian cancer screening having in common? It turns out our judgments about these things are all influenced by unconscious bias.

Moderate carbohydrate intake may be best for health

August 17, 2018
Eating carbohydrates in moderation seems to be optimal for health and longevity, suggests new research published in The Lancet Public Health journal.

Phantom odors: One American in 15 smells odors that aren't there, study finds

August 16, 2018
Imagine the foul smell of an ash tray or burning hair. Now imagine if these kinds of smells were present in your life, but without a source. A new study finds that 1 in 15 Americans (or 6.5 percent) over the age of 40 experiences ...

US drug overdose deaths surge amid fentanyl scourge

August 16, 2018
US drug overdose deaths surged to nearly 72,000 last year, as addicts increasingly turn to extremely powerful synthetic opioid fentanyl as the supply of prescription painkillers has tightened.

Parental life span predicts daughters living to 90 without chronic disease or disability

August 15, 2018
Researchers at the University of California San Diego School of Medicine report that women whose mothers lived to at least age 90 were more likely to also live to 90, free of serious diseases and disabilities.

Widespread declines in life expectancy across high income countries coincide with rising young adult, midlife mortality

August 15, 2018
The ongoing opioid epidemic in the United States is a key contributor to the most recent declines in life expectancy, suggests a study published by The BMJ today.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.