What Is Inflammation and How Does Chronic Inflammation Contribute to Disease?
Inflammation is the body's normal response to trauma, such as an accident or infection. When one is injured or sick, the immune system produces an inflammatory response to assist in protecting and healing the body. This causes the area to turn red, bloated, hot, and painful. This acute or short-term inflammation is helpful since it indicates that the body is combating an infection or attempting to mend damaged tissue. White blood cells rush to the spot, attacking foreign invaders such as germs and removing dead or damaged cells. Increased blood flow delivers nutrients and more cells to aid in healing.
However, inflammation may not always resolve itself and can develop chronic or long-lasting throughout the body. This occurs when the immune system overreacts and attacks healthy cells or is unable to shut down. High quantities of inflammatory markers are constantly produced in the bloodstream.
Chronic inflammation can eventually damage healthy cells. It is associated with a variety of diseases, including heart disease, arthritis, diabetes, cancer, and autoimmune disorders. Obesity also promotes persistent low-grade inflammation due to the development of fat cells, which produce inflammatory chemicals.
What Role Does Fat Reduction Play in Lowering Inflammation Levels in Obesity?
Obesity is a medical disease defined by an excessive buildup of body fat. Inflammation in obesity leads to metabolic dysfunction, insulin resistance, and an increased risk of chronic illnesses such as diabetes and cardiovascular disease.
Excess calorie intake causes adipose tissue to expand and release inflammatory cytokines, including IL-6 (Interleukin-6), TNF-α (Tumor necrosis factor), and CRP(C reactive protein). This leads to insulin resistance, atherosclerosis, and a higher risk of cancer. Dietary measures that lower inflammation may thereby protect against a variety of obesity-related illnesses. Fasting, which involves abstaining totally from food and caloric beverages for varied periods, has recently acquired popularity due to its therapeutic benefits.
In obesity, adipose tissue macrophages and other immune cells secrete pro-inflammatory cytokines like TNF-α and IL-6. Individuals with obesity have two to three times higher levels of these variables than their slim counterparts. As adipose tissue expands, it secretes more adipokines, such as leptin, resistin, and visfatin, which enhance inflammatory pathways. The primary location of inflammation is visceral adipose tissue, which is fat accumulated in the abdominal cavity around organs. Compared to subcutaneous fat, visceral fat has a higher immune cell infiltration and produces more inflammatory cytokines that enter the liver through the portal circulation. Chronic inflammation impairs insulin signaling, which leads to insulin resistance and metabolic instability.
Losing weight can help reduce inflammation in obese people. A study of 24 research indicated that for every 1 kg (2.2 lbs) of weight loss, levels of the inflammatory marker C-reactive protein (CRP) in the blood fell by 0.13 mg/L on average. Simply decreasing five to ten percent of one's baseline body weight can drastically reduce inflammatory levels.
However, it is not simply the overall weight loss that counts. Losing visceral fat, or the deep abdominal fat that surrounds one's organs, is also important for reducing inflammation. One study examined obese people who lowered their calorie intake by diet alone or diet combined with aerobic exercise such as walking.
The diet-only group saw a 32 percent drop in CRP. However, the diet plus exercise group experienced an even greater 48 percent decline in CRP levels. Whether or not the ladies exercised, the amount of visceral fat they reduced predicted how much their CRP levels improved.
So, while losing weight overall is beneficial, eliminating the dangerous visceral abdominal fat appears to be especially crucial for reducing inflammation. The more visceral fat eliminated, the higher the anti-inflammatory effects. Beyond diet, exercise can help with visceral fat loss and inflammation reduction.
What Are the Potential Anti-inflammatory Mechanisms of Fasting?
When one fast for an extended period, the body goes into a state known as ketosis. During ketosis, the body uses stored fat for energy rather than glucose from food. This triggers the release of chemicals known as ketone bodies. These ketones appear to have anti-inflammatory properties. Studies indicate that they can inhibit the production of inflammatory molecules such as IL-6, TNF-α, and IL-1β in human immune cells. These are the markers that cause inflammation.
Fasting and calorie restriction may also inhibit an immune system component known as the NLRP3 inflammasome. The NLRP3 inflammasome triggers inflammatory reactions by producing IL-1β and other inflammatory substances.
So, through the production of ketone bodies and compounds like beta-hydroxybutyrate, fasting may reduce inflammation by suppressing inflammatory molecules and pathways like NLRP3. This could potentially protect against chronic inflammatory disorders driven by excess inflammation.
What Are the Different Clinical Trial Evidence of Fasting on Inflammation?
Time-restricted Feeding (TRF) -
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TRF means only eating during a set window of hours each day and fasting for the remaining hours.
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According to studies, TRF causes a minor weight loss of one to five percent.
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However, the effects of TRF on lowering inflammation markers such as CRP, TNF-alpha, and IL-6 are unknown.
One study examined obese persons who engaged in 6-hour TRF either early (7 am-1 pm eating) or late (12 pm-6 pm eating):
After eight weeks, they shed four to five percent of body weight, but their levels of CRP, TNF-alpha, and IL-6 remained unchanged.
Another study had overweight persons do 8-hour TRF (12 pm-8 pm eating) and resistance exercise: They shed four percent of their weight after eight weeks. However, there are no changes in CRP levels.
Alternate Day Fasting (ADF) -
ADF refers to alternating 24-hour fast days with 24-hour non-fasting "feast" days.
Multiple studies suggest that ADF causes clinically significant 5 to 12 percent weight loss in obese persons over 8-24 weeks.
Some of these investigations discovered CRP levels dropping by 13 to 48 percent when weight loss exceeded 6 percent. Despite this level of weight loss, ADF did not reduce TNF-alpha or IL-6 levels.
One study indicated that ADF resulted in larger CRP reductions than daily calorie-restricted diets, whereas another found no difference.
So far, preliminary research suggests that ADF may help lower CRP, but only if significant weight loss of more than 6 percent is accomplished. More high-quality research is needed to determine whether ADF has superior anti-inflammatory effects than typical daily calorie restriction.
Prolonged or Periodic Fasting
Few studies have investigated prolonged fasts (more than 24 hours) or periodic regimes such as the 5:2 fasting diet.
One trial coupled alternate-day fasting with exercise in obese people for three weeks. 6 percent weight loss happened. A marker termed YKL-40 was associated with inflammation and dropped by 57 percent.
Another study compared one or two consecutive days of fasting per week for 12 weeks in overweight people: Fasting for two days led to greater weight loss, although both groups experienced similar CRP reductions of approximately 17 percent.
More research is certainly needed to determine the impact of varied fasting durations and frequency on inflammatory markers before drawing any conclusions.
What Are the Potential Confounding Factors?
When investigating the anti-inflammatory benefits of fasting, it is critical to account for the degree of calorie or weight loss. Reduced calorie intake, rather than fasting itself, may be more effective at modulating inflammation. Intermittent fasting versus regular calorie restriction matched for weight loss can help separate the particular effects of fasting.
Changes in macronutrient intake also need to be considered. For example, ketogenic diets may have anti-inflammatory benefits. If fasting increases fat intake, it may contribute to inflammation reduction.
The gut microbiota mediates the connections between food, metabolism, and inflammation. Fasting-induced alterations in gut bacteria may influence inflammatory indicators independently of weight loss. Monitoring microbiota alterations during fasting will help us understand their role.
The consequences of fasting are most likely determined by individual characteristics such as age, gender, obesity, underlying inflammation, and comorbidities. More studies with varied demographics are needed.
Conclusion
While preliminary data suggests that intermittent fasting may lower inflammation, particularly indicators such as CRP, the extent of these effects is heavily dependent on the amount of weight loss accomplished. More high-quality research is needed to discover the precise anti-inflammatory benefits of various fasting regimens while controlling for factors such as calorie intake, macronutrient composition, and individual characteristics. Nonetheless, fasting shows promise as a treatment for chronic inflammatory diseases.
