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Vitamin A Boosts Fat Burning in Cold Conditions, Study Suggests

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Key Takeaways

  • White body fat, which stores excess calories, turns brown when fat burning and heat generation is stimulated.
  • A study found that cold temperatures increased vitamin A levels, which helps convert white fat to brown fat and thus stimulates fat burning.
  • However, there’s no evidence that taking vitamin A supplements is helpful for weight loss.

If you find it hard to get excited about the idea of going out for a run during the winter months, a new study might make you think differently. Research from the Medical University of Vienna, published in the journal Molecular Metabolism, found that cold temperatures and higher levels of vitamin A encourage fat burning.

Humans can have white fat or brown fat. In healthy individuals, white fat makes up around 10% of body weight. According to the researchers, white fat is where excess calories are stored. But when white fat is converted to brown fat, this stimulates fat burning and heat generation. 

Study Findings

The team, which included scientists from Harvard University, Boston, and Rutgers University, New Jersey, used mice to show that cold temperatures increase vitamin A levels (mostly stored in the liver), which help convert white fat to brown fat and stimulate fat burning.

When the mice were exposed to cold, the increases in the levels of vitamin A (and its blood transporter, retinol-binding protein) resulted in a higher rate of fat burning. As the mice tried to keep warm, their white fat converted to brown fat. 

On the other hand, when the vitamin A transporter retinol-binding protein was blocked in mice, the fat didn’t go brown, and the mice weren’t able to protect themselves from the cold. 

The researchers also examined humans, although due to ethical reasons, the study process was different. The researchers exposed 30 human subjects to cold temperatures and found increased levels of vitamin A. Researchers also extracted human cells from the belly fat of four donors. When they stimulated the cells with vitamin A, the cells displayed browning behavior.

Florian Kiefer

Our findings show that vitamin A is a potent regulator of fat cell function – it mediates fat burning during cold conditions.

— Florian Kiefer

“Our findings show that vitamin A is a potent regulator of fat cell function – it mediates fat burning during cold conditions,” says the study’s lead researcher, Florian Kiefer. He hopes that the discovery of a new mechanism by which vitamin A regulates lipid combustion and heat generation in cold conditions could help scientists to develop new therapeutic interventions for weight gain and obesity.

However, Kiefer warned against taking large quantities of vitamin A supplements to try to lose weight. “It is important that vitamin A is transported to the right cells at the right time,” he explains. 

More Research Is Needed

Emory Hsu, MD, an endocrinologist with Santa Clara Valley Medical Center in San Jose, California, says the study is a fairly preliminary look at cellular mechanisms. “There are hundreds of thousands of proteins and genes at work in the adipose cells (fat cells), so findings that one or two are increased or decreased in certain conditions shouldn’t automatically lead to over-excitement for a clinical treatment for obesity,” he says. “It will take a lot of research to untangle all the mechanisms and find some that can be treated clinically.”  

Emory Hsu, MD

For most people, there is no need to go out and take a vitamin A supplement; the amount you get from your diet or a regular multivitamin should be fine.

— Emory Hsu, MD

Dr. Hsu adds that there’s no evidence at this point that taking vitamin A supplements is helpful for obesity. “In the United States, vitamin A deficiency is almost unheard of,” he explains. “For most people, there is no need to go out and take a vitamin A supplement; the amount you get from your diet or a regular multivitamin should be fine.”

The exceptions may be if you have digestive tract issues, such as a history of bariatric surgery, inflammatory bowel diseases, or issues affecting the pancreas (which makes enzymes that help digest fat—vitamin A is a fat-soluble vitamin, remember) such as cystic fibrosis. “In those cases, it can be worth it to check with a dietician or your doctor,” Dr. Hsu says. 

What This Means For You

Speak to your doctor before taking a vitamin A supplement—most people don't need it. Taking too many supplements or eating too much organ meat that contains a lot of vitamin A (like liver or kidney) can cause toxicity.

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Article Sources
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  1. Fenzl A, Kulterer OC, Spirk K, et al. Intact vitamin A transport is critical for cold-mediated adipose tissue browning and thermogenesis. Mol Metab. 2020;42:101088. doi:10.1016/j.molmet.2020.101088

  2. Elattar S, Satyanarayana A. Can brown fat win the battle against white fat?. J Cell Physiol. 2015;230(10):2311-7. doi:10.1002/jcp.24986

  3. National Institutes of Health; Office of Dietary Supplements. Vitamin A: Fact Sheet for Health Professionals. Updated February 14, 2020.