Fasting diets favored by celebs may increase the risk of cancer

By Mark Waghorn via SWNS

Fasting diets favored by celebrities may increase the risk of cardiovascular disease and cancer, according to new research.

Skipping meals, including breakfast, triggers a reaction in the brain that damages immune system cells, say scientists.

The first study of its kind sheds fresh light on the potential long-term effects of the trendy lifestyle.

Lead author Dr. Filip Swirski, of Icahn Mount Sinai, New York, said: "There is a growing awareness that fasting is healthy, and there is indeed abundant evidence for the benefits of fasting.

"Our study provides a word of caution as it suggests that there may also be a cost to fasting that carries a health risk.

"This is a mechanistic study delving into some of the fundamental biology relevant to fasting. The study shows that there is a conversation between the nervous and immune systems."

Time-restricted eating has become fashionable. Proponents include Gisele Bundchen, Jennifer Aniston, Kourtney Kardashian and Scarlett Johansson. They go without food between certain hours - or on specific days.

The findings are based on mice. One group was given breakfast, their largest meal of the day, right after waking up. The other went without.

Specifically, the researchers identified a difference in the number of monocytes - white blood cells made in the bone marrow that fight infections, heart disease and cancer.

At the outset, all lab rodents had the same amount. But after four hours 90 percent disappeared from the bloodstream of the fasting set - with further decline at eight hours.

Scans showed the monocytes traveled back to the bone marrow to hibernate. Production diminished and survivors changed.

They survived longer and aged differently from those that stayed in the blood.

The researchers continued to fast mice for up to 24 hours and then reintroduced food.

The cells hiding in the bone marrow surged back into the bloodstream within a few hours.

This led to a heightened level of inflammation. Instead of protecting against infection, they made the body more vulnerable.

Further analysis showed specific regions in the brain controlled the monocyte response during fasting.

It elicited a stress response dubbed 'hangry' - feeling hungry and angry.

This instantly triggers a large-scale migration of white cells to the bone marrow and then back to the bloodstream shortly after food is reintroduced.

Dr. Swirski said: "The study shows that, on the one hand, fasting reduces the number of circulating monocytes, which one might think is a good thing, as these cells are important components of inflammation.

"On the other hand, the reintroduction of food creates a surge of monocytes flooding back to the blood, which can be problematic.

"Fasting therefore regulates this pool in ways that are not always beneficial to the body's capacity to respond to a challenge such as an infection.

"Because these cells are so important to other diseases like heart disease or cancer, understanding how their function is controlled is critical."

Intermittent fasting diets have become popular in recent years as weight loss regimes.

The idea is doing it for a certain number of hours each day or eating just one meal a couple of days a week helps the body burn fat.

The American Heart Association advises that altering meal frequency may not be useful.

The study is published in the journal Immunity.