The case for low-cal: Studies suggest fasting may cut chronic disease risks by reducing inflammation – and eating fewer calories may boost immunity
- Researchers put some mice on restricted diets and others ate freely before and after introducing a bacterial infection
- The mice on restricted diets had immune cells that better recognized the infections and were able to fight them off
- Scientists also found that periods of intermittent fasting reduced the number of monocytes, pro-inflammatory white blood cells, circulating in the blood
Periodic fasting may reduce the risk of chronic disease by keeping inflammatory immune cells at bay, a new study suggests.
What’s more, a second new study suggests that eating fewer calories – enough, but not more than an individual needs for nourishment – may supercharge other infection-fighting immune cells.
The teams – from the National Institute of Allergy and Infectious Diseases (NIAID) and the Mount Sinai Health System in New York City – both say this could lead to doctors recommending a nutritional plan coupled with traditional treatments for patients suffering from infections or certain cancers.
‘All these studies synergize to show that a simple change in diet can have a profound effect on our immune system,’ Dr Yasmine Belkaid, chief of the Metaorganism Immunity Section in NIAID’s Division of Intramural Research, told DailyMail.com.
Two new studies have found that mice on calorie-restricted diet had lower pro-inflammatory immune cells as well as immune cells that were better at recognizing infectious diseases (file image)
In the first study, published in Cell, Mount Sinai researchers looked at mouse and human immune cells after periods of sporadic fasting.
They found that fasting lowed the number of monocytes, white blood cells that are pro-inflammatory, circulating in the blood.
‘Monocytes are highly inflammatory immune cells that can cause serious tissue damage, and the population has seen an increasing amount in their blood circulation as a result of eating habits that humans have acquired in recent centuries,’ said Dr Merad, the senior author.
Inflammation can be a normal immune system response to fight off infections, but chronic inflammation can lead to heart disease, diabetes and even cancer.
‘Considering the broad spectrum of diseases that are caused by chronic inflammation and the increasing number of patients affected by these diseases, there is an enormous potential in investigating the anti-inflammatory effects of fasting,’ said first author Dr Stefan Jordan, a postdoctoral fellow in the department of oncological sciences at the Icahn School of Medicine at Mount Sinai.
Dr Belkaid added that the studies show fasting and caloric restriction is not a fad, and there is now ‘ a rigorous scientific explanation’ of its benefits.
‘I believe nutritional intervention will be the future of medicine – a change in diet, change in calories and certain nutrients – partnered with traditional medicine to tame and manipulate the immune system.’
For the second study, also published in the journal Cell, the team from NIAID restricted the diets of mice that were previously eating a normal diet.
On restricted diets, the rodents had fewer memory T cells in lymphoid tissue – where they normally are – and more T cells in bone marrow, which generates blood cells.
Then, without restricting their diets, all the mice were infected with the bacterium Yersinia pseudotuberculosis, which causes Far East scarlet-like fever in humans.
Once the rodents had developed an immunological memory, some of the mice were put on restricted diets for four weeks before they were all exposed to the bacterium again.
This immune system recall – programmed into memory T cells, which fight infections and cancer – was better at recognizing infectious diseases they had already encountered and fighting them off again than those of the mice who ate freely.
Researchers conducted the experiment again, this time with a vaccine that trains immune system cells to fight off melanomas, or skin cancer.
Mice on restricted diets had memory T cells they were better and fighting off tumors that the mice who weren’t on these diets.
‘What we expected was the mice on restricted diet would as protected as the mice not restricted,’ said Dr Belkaid.
‘What we did not expect was they would be better protected.’
Mice on restricted diets had memory T cells they were better and fighting off tumors that the mice who weren’t on these diets.
The team says that, although the study in rodents may not directly translate to humans, the findings suggest the immune system of mammals may have evolved to ensure a strong immune system even when food is scarce.
‘If you reduce calories, the natural response is to save cells, so the cells hide [in bone marrow] to receive nutrients needed to survive,’ said Dr Belkaid.
‘But in bone marrow, the T cells acquire an enhanced protective function.
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