Fasting May Reduce Inflammation – Neuroscience News
summary: Researchers have revealed a new mechanism through which fasting reduces inflammation, a major factor in chronic diseases.
Their study revealed that fasting increases blood levels of arachidonic acid, which inhibits the NLRP3 inflammasome, thus reducing inflammation. This discovery highlights the anti-inflammatory effects of fasting and provides insight into the benefits of calorie restriction for conditions such as obesity, diabetes, heart disease, and neurodegenerative disorders.
The research also provides clues about how drugs such as aspirin work, further highlighting the complex relationship between diet, inflammation and disease prevention.
- Fasting raises blood arachidonic acid levels, leading to decreased NLRP3 inflammasome activity and inflammation.
- The findings offer a potential explanation for how fasting and calorie restriction protect against chronic diseases associated with inflammation.
- This research may also explain the anti-inflammatory effects of nonsteroidal anti-inflammatory drugs such as aspirin, which increase arachidonic acid levels.
source: Cambridge University
Cambridge scientists may have discovered a new way in which fasting helps reduce inflammation, a potentially harmful side effect of the body’s immune system that underlies a number of chronic diseases.
In a paper titled “Arachidonic acid inhibition of the NLRP3 inflammasome is a mechanism to explain the anti-inflammatory effects of fasting,” published in Cell reportsThe team describes how fasting raises levels of a chemical in the blood known as arachidonic acid, which prevents inflammation.
Researchers say it may also help explain some of the beneficial effects of drugs like aspirin.
Scientists have known for some time that our diet — especially the high-calorie Western diet — can increase the risk of diseases including obesity, type 2 diabetes and heart disease, which are linked to chronic inflammation in the body.
Inflammation is the body’s normal response to injury or infection, but this process can be stimulated by other mechanisms, including what is called an “inflammasome,” which acts as an alarm inside the body’s cells, triggering inflammation to help protect the body when it senses damage.
But the inflammasome can lead to inflammation in unintended ways. One of its jobs is to destroy unwanted cells, which can release the cell contents into the body, where they lead to inflammation.
Professor Clare Bryant, from the Department of Medicine at the University of Cambridge, said: “We are very interested in trying to understand the causes of chronic inflammation in the context of many human diseases, and in particular the role of the inflammasome.
“What has become clear over recent years is that one inflammasome in particular – the NLRP3 inflammasome – is very important in a number of major diseases such as obesity and atherosclerosis, but also in diseases such as Alzheimer’s disease, Parkinson’s disease, and many diseases of the elderly. People, Especially in the Western world.”
Fasting can help reduce inflammation, but the reason is not clear. To help answer this question, a team led by Professor Bryant and colleagues at the University of Cambridge and the National Institutes of Health in the US studied blood samples from a group of 21 volunteers, who ate a 500-calorie meal and then fasted for 24 hours. Before eating the second meal, which contains 500 calories.
The team found that restricting calorie intake increased levels of a fat known as arachidonic acid. Fats are molecules that play important roles in our bodies, such as storing energy and transferring information between cells. Once individuals eat a meal again, arachidonic acid levels decrease.
When researchers studied the effect of arachidonic acid on immune cells grown in the laboratory, they found that it reduced the activity of the NLRP3 inflammasome. This surprised the team, as arachidonic acid was previously thought to be associated with increased levels of inflammation, not decreased levels.
Professor Bryant, a Fellow of Queen’s College, Cambridge, added: “This offers a possible explanation for how changing our diet – particularly by fasting – protects us from infections, especially the harmful form that underlies many of the diseases associated with Western Altitude Syndrome.” Calorie diet.
“It is too early to say whether fasting protects against diseases such as Alzheimer’s and Parkinson’s disease, because the effects of arachidonic acid are only short-lived, but our work adds to a growing amount of scientific literature that points to the health benefits of calorie restriction. It suggests that regular fasting “Over a long period of time it could help reduce the chronic inflammation that we associate with these conditions. It’s certainly an attractive idea.”
The findings also suggest one mechanism by which a high-calorie diet may increase the risk of these diseases. Studies have shown that some patients who follow a high-fat diet have increased levels of inflammasome activity.
“There could be a yin and yang effect going on here, where too much of the wrong thing will increase your inflammatory activity and too little will reduce it,” Professor Bryant said. “Arachidonic acid could be one way this happens.”
The discovery may also provide clues to an unexpected way in which so-called non-steroidal anti-inflammatory drugs such as aspirin work, researchers say. Normally, arachidonic acid is rapidly broken down in the body, but aspirin stops this process, which may lead to increased levels of arachidonic acid, which in turn reduces inflammasome activity and thus inflammation.
Professor Bryant said: “It is important to stress that aspirin should not be taken to reduce the risk of long-term disease without medical guidance, as it can have side effects such as stomach bleeding if taken over a long period.”
About this diet and inflammation research news
author: Claire Bryant
source: Cambridge University
communication: Claire Bryant – University of Cambridge
picture: Image credited to Neuroscience News
Original search: Open access.
“Arachidonic acid inhibition of the NLRP3 inflammasome is a mechanism to explain the anti-inflammatory effects of fasting” by Milton Pereira et al. Cell reports
Arachidonic acid inhibition of the NLRP3 inflammasome is a mechanism to explain the anti-inflammatory effects during fasting
- In fasted compared to fed subjects, plasma IL-1β is lower and arachidonic acid (AA) is higher.
- Exogenous AA impairs NLRP3 inflammasome activity in human and mouse macrophages
- AA inhibits phospholipase C and reduces JNK stimulation and thus NLRP3 activity
Elevated interleukin (IL)-1β levels, NLRP3 inflammasome activity, and systemic inflammation are hallmarks of chronic metabolic inflammatory syndromes, but the mechanistic basis for this is unclear.
Here, we show that plasma IL-1β levels are lower in fasting compared to fed subjects, while the fatty acid arachidonic acid (AA) is elevated.
Lipid profiling of NLRP3-stimulated mouse macrophages shows enhanced AA production and an NLRP3-dependent eicosanoid signature.
Inhibition of cyclooxygenase by NSAIDs reduces eicosanoid production, but not AA production. It also reduces the production of both IL-1β and IL-18 in response to NLRP3 activation.
AA inhibits NLRP3 inflammasome activity in human and mouse macrophages. Mechanistically, AA inhibits phospholipase C activity to reduce JNK1 stimulation and thus NLRP3 activity.
These data demonstrate that AA is an important physiological regulator of the NLRP3 inflammasome, explain why fasting reduces systemic inflammation, and suggest a mechanism to explain how NSAIDs work.