The role of vitamin A in diabetes

June 13, 2017

There has been no known link between diabetes and vitamin A - until now. A new study suggests that the vitamin improves the insulin producing β-cell´s function.

The researchers initially discovered that insulin-producing beta-cells contain a large quantity of a cell surface receptor for vitamin A.

"There are no unnecessary surface receptors in human cells. They all serve a purpose but which, in many cases, is still unknown and because of that they are called "orphan" receptors. When we discovered that insulin cells have a cell surface expressed receptor for vitamin A, we thought it was important to find out why and what the purpose is of a cell surface receptor interacting with vitamin A mediating a rapid response to vitamin A", explains Albert Salehi, senior researcher at the Lund University Diabetes Centre in Sweden.

The researchers believe that the purpose, in this particular case, is that vitamin A plays an important role for the development of beta-cells in the early stages of life, but also for a proper function during the remaining life especially during pathophysiological conditions, i.e some inflammatory conditions.

Albert Salehi and his research team, together with their colleagues at the University of Gothenburg, King's College (London) and the Oxford Centre for Diabetes, have mapped 220 different receptors on the surface of the beta cell, whose features are still not fully known. One of the findings is the cell surface expressed receptor for vitamin A.

In order to study the role of the vitamin in cases of diabetes, the researchers worked with insulin cells from mice and non-diabetic and type 2 diabetic donors. By partially blocking the vitamin A receptor and challenging the cells with sugar, they could see that the cells' ability to secrete insulin deteriorated.

"We saw close to a 30 per cent reduction", says Albert Salehi, adding that impaired cell survival and insulin secretion are key causes of type 2 diabetes.

The same tendency could be seen when comparing insulin cells from type 2 diabetic donors. Cells from patients with type 2 diabetes were less capable of insulin secretion compared with cells from people without diabetes.

The researchers also saw that the beta-cells' resistance to inflammation decreases in the absence of vitamin A. In case of a complete deficiency, the cells die. The discovery may also be significant for certain types of type 1 diabetes when the beta-cells are not sufficiently developed during the early stages of life.

"In animal experiments it is known that newborn mice need vitamin A to develop their beta-cells in a normal way. Most likely, the same applies to human beings. Children must absorb a sufficient amount of vitamin A through their diet", says Albert Salehi.

Vitamin A is found mainly in offal and dairy products. In Sweden, milk is enriched with vitamin A. There appears to be no vitamin A deficiency in Sweden in people who eat a standard variety of food, but vegetarians perhaps need to be aware of the problem.

Too much vitamin A is harmful and can lead to osteoporosis. However, there is no risk of excessive intake through food - the risk lies in taking dietary supplements. Defects associated with vitamin A deficiency are, among other things, impaired night vision and reduced elasticity in the skin and mucous membranes.

In the event of a diabetes treatment based on the newly found cell surface receptor for vitamin A, Albert Salehi believes that the risk of excessive intake makes the vitamin A itself inappropriate.

"But we're trying to find substances such as small molecules or peptides that are similar to the vitamin A could activate the newly found receptor while lacking the unwanted effects" of vitamin A", he concludes.
-end-


Lund University

Related Diabetes Articles from Brightsurf:

New diabetes medication reduced heart event risk in those with diabetes and kidney disease
Sotagliflozin - a type of medication known as an SGLT2 inhibitor primarily prescribed for Type 2 diabetes - reduces the risk of adverse cardiovascular events for patients with diabetes and kidney disease.

Diabetes drug boosts survival in patients with type 2 diabetes and COVID-19 pneumonia
Sitagliptin, a drug to lower blood sugar in type 2 diabetes, also improves survival in diabetic patients hospitalized with COVID-19, suggests a multicenter observational study in Italy.

Making sense of diabetes
Throughout her 38-year nursing career, Laurel Despins has progressed from a bedside nurse to a clinical nurse specialist and has worked in medical, surgical and cardiac intensive care units.

Helping teens with type 1 diabetes improve diabetes control with MyDiaText
Adolescence is a difficult period of development, made more complex for those with Type 1 diabetes mellitus (T1DM).

Diabetes-in-a-dish model uncovers new insights into the cause of type 2 diabetes
Researchers have developed a novel 'disease-in-a-dish' model to study the basic molecular factors that lead to the development of type 2 diabetes, uncovering the potential existence of major signaling defects both inside and outside of the classical insulin signaling cascade, and providing new perspectives on the mechanisms behind insulin resistance in type 2 diabetes and possibly opportunities for the development of novel therapeutics for the disease.

Tele-diabetes to manage new-onset diabetes during COVID-19 pandemic
Two new case studies highlight the use of tele-diabetes to manage new-onset type 1 diabetes in an adult and an infant during the COVID-19 pandemic.

Genetic profile may predict type 2 diabetes risk among women with gestational diabetes
Women who go on to develop type 2 diabetes after having gestational, or pregnancy-related, diabetes are more likely to have particular genetic profiles, suggests an analysis by researchers at the National Institutes of Health and other institutions.

Maternal gestational diabetes linked to diabetes in children
Children and youth of mothers who had gestational diabetes during pregnancy are at increased risk of diabetes themselves, according to new research published in CMAJ (Canadian Medical Association Journal).

Two diabetes medications don't slow progression of type 2 diabetes in youth
In youth with impaired glucose tolerance or recent-onset type 2 diabetes, neither initial treatment with long-acting insulin followed by the drug metformin, nor metformin alone preserved the body's ability to make insulin, according to results published online June 25 in Diabetes Care.

People with diabetes visit the dentist less frequently despite link between diabetes, oral health
Adults with diabetes are less likely to visit the dentist than people with prediabetes or without diabetes, finds a new study led by researchers at NYU Rory Meyers College of Nursing and East Carolina University's Brody School of Medicine.

Read More: Diabetes News and Diabetes 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.