News Fresh Today: Fasting diet may help regenerate a diabetic pancreas

"The pancreas can be triggered to regenerate itself through a type of fasting diet, say US researchers," BBC News reports.

Research in mice found a low-calorie diet may help in cases of type 1 and type 2 diabetes.

The pancreas is an organ that uses specialised cells known as beta cells to produce the hormone insulin, which the body uses to break down sugars in the blood (glucose).

In type 1 diabetes the pancreas stops producing insulin. In type 2 diabetes either not enough insulin is produced or cells in the body fail to respond to insulin (insulin resistance).

Mice were fed for four days on a low-calorie, low-protein and low-carbohydrate but high-fat diet, receiving half their normal daily calorie intake on day one, followed by three days of 10% of their normal calorie intake.

Researchers repeated this fast on three occasions, with 10 days of refeeding in between. They then examined the pancreas.

They found in mice modelled to have both type 1 and type 2 diabetes, insulin production was restored, insulin resistance was reduced, and beta cells could be regenerated. Early lab study involving human cell samples showed similar potential.

These are promising results, but further studies are needed to validate these findings in humans.

If you have either type 1 or type 2 diabetes, you shouldn't attempt a fasting diet without first seeking medical advice. A sudden change in your calorie intake could have unpredictable effects and lead to complications.

Where did the story come from?

The study was carried out by researchers from the University of Southern California and the Koch Institute at the Massachusetts Institute of Technology (MIT) in the US, and the IFOM FIRC Institute of Molecular Oncology in Italy.

It was funded by grants from the US National Institutes of Health (NIH) and the US National Institute on Aging (NIA).

The study was published in the peer-reviewed journal, Cell. It's available on an open access basis and is free to read online (PDF, 6.74Mb).

The UK media coverage of the research is generally accurate. BBC News provided useful advice from one of the authors, Dr Longo, who cautioned: "Do not try this [fasting] at home. This is so much more sophisticated than people realise".

What kind of research was this?

This animal study examined whether a diet mimicking fasting cycles is able to promote the generation of new pancreatic beta cells in a mouse model of diabetes.

Beta cells are found in the pancreas. The cells' primary function is to store and release insulin in response to changes in blood glucose concentration.

In people with diabetes, the beta cells are either destroyed by the person's own immune system (type 1) or are unable to produce a sufficient amount of insulin (type 2).

Beta cells are reported to be highly sensitive to the availability of nutrients. The researchers wanted to see whether prolonged fasting and refeeding could regenerate pancreatic cells.

Animal studies like this one are useful early-stage research to help better our understanding of cellular mechanisms.

However, the human body has complex biology and we're not identical to mice, so further studies would be needed to see whether the same effects are observed in humans.

What did the research involve?

The first phase of the study involved male mice aged 10-16 weeks, some of whom had injections of a chemical to destroy their beta cells to mimic type 1 diabetes. Others were genetically bred to have type 2 diabetes, and normal mice acted as controls.

The researchers put the mice on a four-day fasting regimen consisting of a low-calorie, low-protein, low-carbohydrate and high-fat (FMD) diet.

They were fed 50% of their standard calorie intake on day one, followed by 10% of their normal calorie intake on days two to four.

At the end of the four days, the mice were fed regularly for up to 10 days to ensure they regained their body weight before the next fasting cycle. They underwent three dietary intervention cycles.

Blood glucose measurements were taken regularly. Pancreatic cell samples were taken to look at gene activity and investigate whether there were any changes.

The second phase of the study involved analysing human pancreatic cell samples collected from people with type 1 diabetes.

Researchers also recruited healthy human adult volunteers without a history of diabetes, who underwent three cycles of a similar five-day fasting regimen. The blood samples from these people were applied to the cultured pancreatic human cells.

What were the basic results?

In the mouse model of type 2 diabetes, after the FMD cycles insulin secretion was restored and insulin resistance was reduced. The FMD cycles seemed to induce beta cell regeneration.

In the mouse model of type 1 diabetes, FMD cycles were able to reduce inflammation and promote changes in the levels of cytokine proteins, which may indicate the restoration of insulin secretion. There was an increase in the proliferation and number of beta cells generating insulin.

The results in the human cell samples suggested similar findings to those seen in mice. FMD cycles – that is, in blood samples from fasted individuals applied to human pancreatic cells in the laboratory – may be able to promote reprogramming of cell lineages and generate insulin in pancreatic islet cells.

How did the researchers interpret the results?

The researchers concluded that, "These results indicate that an FMD promotes the reprogramming of pancreatic cells to restore insulin generation in islets from T1D [type 1 diabetes] patients and reverse both T1D and T2D [type 2 diabetes] phenotypes in mouse models."

Conclusion

This animal study examined whether a diet mimicking fasting cycles would be able to promote the generation of new insulin-producing pancreatic beta cells in a mouse model of diabetes.

Overall, researchers found in mice models of both type 1 and type 2 diabetes, insulin secretion was restored and insulin resistance and beta cells could be regenerated or have their function restored. Very early laboratory study on human cell samples suggested similar potential.

These results show promise, but further research is needed to validate these findings in humans.

Professor Anne Cooke, professor of immunology at the University of Cambridge, commented: "This is good science and does give promise for the future treatment of diabetes, but we need further studies to see whether this works in people as well as it has in mice."

Don't suddenly try fasting, or any other radical change to your diet, without first consulting the doctor in charge of your care. Sudden changes to your diet could cause complications.