Could vitamin A deficiency be a cause of type 2 diabetes?

A new study published in The Journal of Biological Chemistry claims to have identified a potential driver of type 2 diabetes: vitamin A deficiency. The researchers, from the Weill Cornell Medical College in New York, NY, say their findings may lead to new treatments for the condition.

Lack of vitamin A - found in many fruits, vegetables, meats and dairy products - may be involved in development of type 2 diabetes, according to researchers.

Type 2 diabetes is the most common form of diabetes in the US, accounting for 90-95% of all diagnosed cases.

The condition is characterized by insulin resistance, in which insulin-producing beta cells in the pancreas are unable to function effectively.

According to researchers at Weill Cornell vitamin A boosts beta cell activity, meaning lack of the vitamin may play a role in the development of type 2 diabetes.

There are two types of vitamin A. Preformed vitamin A, referred to as retinol, is present in meat, poultry, fish and dairy products, while pro-vitamin A, or beta-carotene, is found in many fruits and vegetables. Vitamin A aids cell growth and contributes to a healthy immune system and vision.

Past studies have shown that, during fetal development, vitamin A is key for beta cell production. But the reseachers say it was unclear as to whether vitamin A played such a role in adulthood.

Removal of dietary vitamin A led to beta cell loss in adult mice

To find out, the team analyzed the beta cell development among two groups of adult mice; one group of mice had been genetically modified to be unable to store dietary vitamin A, while the other group was able to store the vitamin from foods as normal.

The researchers found that the mice unable to store vitamin A experienced beta cell death, meaning these mice were unable to produce insulin.

What is more, when the researchers removed vitamin A from the diets of healthy mice, they found this led to significant beta cell loss, resulting in reduced insulin production and increased blood glucose levels - key factors involved in development of type 2 diabetes. When the researchers restored vitamin A to the rodents' diets, beta cell production rose, insulin production increased and blood glucose levels returned to normal.

The researchers say their findings indicate that vitamin A deficiency may be involved in the development of type 2 diabetes. 

"How the removal of vitamin A causes the death of the beta cells that make insulin in the pancreas is an important question we want to answer.

These beta cells in the pancreas are exquisitely sensitive to the dietary removal of vitamin A. No one has found that before. Our study sets the platform to take these studies further into preclinical and clinical settings."

The research team says their findings also suggest a synthetic form of vitamin A may have the potential to reverse type 2 diabetes - something they plan to address in future research.

In November 2014, another team of researchers reported on a study suggesting verapamil - a common drug used to treat high blood pressure, irregular heartbeat and migraine headaches - has the potential to reverse diabetes.

References;

1.  Vitamin A deficiency causes hyperglycemia and loss of pancreatic β-cell mass, Lorraine Gudas, et al., The Journal of Biological Chemistry , doi: 10.1074/jbc.M114.616763, published online 1 December 2014.
2.  Weill Cornell Medical College news release, accessed 19 January 2015.
3.  Additional source: Centers for Disease Control and Prevention, diabetes statistics, accessed 19 January 2015.
4.  Additional source: MedlinePlus, vitamin A, accessed 19 January 2015.