Fasting is generally known as a practice done only for religious purposes. Both eastern and western beliefs consider it as a means to help cleanse one's soul. But lately, modern-day medical practitioners have uncovered that perhaps fasting has more benefits than we can ever imagine. Among these benefits that have been tested by various studies is that fasting can help in improving our body's primary defense against pathogens like bacteria and viruses. But why does fasting boost the immune system? How does refraining from eating any foods for a day or two can greatly benefit one's health?
One of the first to discover and provide an explanation to this question is Dr. Valter Longo of the University of Southern California. His study on aging and longevity provides an outstanding result involving the mice and humans who underwent 3 days of fasting. What he and his colleague found out that time heralds the start of brand new perception regarding fasting.
Fasting Triggers White Blood Cells Production
We all know how important the white blood cells (WBC) or lymphocytes are in our body. It acts as the soldier that quickly disposed of any foreign pathogens that enter our body that pose a risk to our health. Without them, our susceptibility to diseases may be doubled or tripled. They are for the most part the most important component of our immune system.
But like any other cells, white blood cells are prone to wear and tear. Once they deteriorate, their effectiveness in defending our body is drastically decreased. But according to the study of Longo, white blood cells can be replenished through undergoing two to three days of fasting. This will lead to the total exhaustion of glycogen or the energy reserves in our body which happens after 24 to 48 hours without consuming anything other than water.
When this happens, the WBC count in one's body will be decreased. This becomes possible due to the reduction of the enzyme PKA as well as the IGF-1 hormone which are core elements for WBC. Then, once you start eating again, your stem cells will have a kick start which triggers the production of new WBC that will replenish that one that was recycled during the fasting period. New WBCs are healthier and ready to fight back any pathogens in your body with much greater potency. In addition to this, through fasting, the immune system removes any of its unused or old components which also give way for our body to replace them with new ones in the process.
The said study of Longo also displays the benefits of three-day fasting in cancer patients who are undergoing chemotherapy. Though chemotherapy technically kills cancer cells, it can also be the cause of why cancer patients acquire a condition called immunosuppression which adversely reduces the capability of our immune system to protect us from infections and other diseases. Fasting based on Longo's conclusion can reduce the risk that might be brought by chemotherapy specifically immunosuppression.
Switching From Glucose To Ketone
The most recent study that proves fasting can boost the immune system was conducted by Cabo and Mattson wherein the results of their work were published at the New England Journal of Medicine. According to their study, an intermittent diet can offer tons of benefits for one's health. This is quite more interesting and easier to be done as compared to the three-day diet of Longo which some might find too challenging to try.
Intermittent diet can be done through two methods: one is to fast two days a week or undergo time-restricted fasting where you will eat lunch at exactly 12 noon then by 8 PM you must eat your dinner already. You will eat the next day again at 12 noon. This will be a daily fasting habit that must be done without a miss.
But how do these fasting diets affect your immune system in a good way? The secret lies in what happens to our metabolism when we start to stop consuming our normal three meals per day diet. Originally, our body is used to a glucose-based metabolism where eating three times a day provides our body with enough energy in the form of glucose to keep us in top shape. Glucose is a kind of sugar that came from the food we eat as they are broken down by our digestive enzymes. This sugar acts as the fuel of our cells so that they can function on a day to day basis.
When our body doesn't receive any glucose due to fasting, it will still allow us to be active by switching the metabolism to ketones instead. Ketones serve as an alternative sugar and are produced by our liver to continue to fuel our cells despite insufficient glucose. In a basic sense, ketone is a chemical converted from fat which will then flow down into your bloodstream.
Ketones, based on the findings of Mattson and Cabo, help in increasing our body's defense against stress, aging, and decreases its susceptibility from diseases. Other than that, switching from glucose to ketones can also reduce inflammation, aids in cutting weight, and tones down blood pressure.
Fasting Empowers Cells Responsible For Body's Overall Defense
Dr. Yasmine Belkaid, an expert on the human immune system, has also found some interesting facts about fasting and on how it can boost particular cells in our body that are key players to keep our immune system in good shape. Although the said experiment they conducted only involved mice, the results are somehow parallel to the effects of fasting being observed by many involving human tests.
The said experiment tested mice wherein their calorie intake is cut down to 20% which is equivalent to reducing one meal they take a day. As they examine these mice during the fasting period, they notice that the T and B cells which function as the ones who build-up our immunity against infection suddenly disappear from the blood of the mice. These cells actually went to the mice's marrow in order to survive the fasting session. But it turns out that they just don't stay there to be safe. The T and B cells actually become stronger as they stay for a while in the marrow and greatly improves their ability to keep our immunity in healthy condition.
In connection with this study, fasting can also alleviate inflammation in one's body. The reason behind it is that monocytes, which are also one of the cells that defend our body from pathogens, are reduced during fasting wherein the bone marrow only reduces a few of them into the bloodstream. These lead to a decrease of inflammation all over the body and makes the mice, which are all being tested in the experiment, look healthier. This finding seems to be linked to the test conducted that explains why fasting helps in countering the symptoms of sclerosis on human trials.
All in all, the study showcases that the immune system might be able to optimize the base from the changes in our diet.
Intermittent Fasting Can Help In Fighting Cancers
Last April 2020, a study was published at ScienceDirect's Journal of Proteomics Vol 217 which features another breakthrough when it comes to fighting cancer as well as improving the body's overall functions, particularly in the immune system. The study was spearheaded by Ayse L. Mindikoglu and Sung Yun Jung and involves a 30-day intermittent fasting done by their 14 subjects all in healthy condition and at the age of 32. Their fasting commences from dawn until sunset where the subjects will eat only their dinner for 30 or a total of 14 hours a day without eating anything.
After the 30-day fasting, blood samples were collected from the subjects and there, they discovered that fasting allows our body to increase the production of known proteins that are commonly decreased in numbers when one is afflicted with cancer which eventually leads to the complications of metastasis and difficulty in prognosis. These proteins include ASAP1 which are scaled-down when an individual is affected by ovarian cancer and the RGNEF which is a primary protein that ceases the development of the tumor in colon cancer patients.
Through fasting, these special proteins are being enhanced and undergo increased production in the body of the subjects after the 30-day fast. But this is not the only benefit that one can gain from fasting according to their conclusion. The said fasting diet also boosts the regulation of a gene responsible for the repairing of damaged DNA in our body. In addition to this, fasting has also shown to help our body regulate more the ASGR2 gene that is known for the task of immunoregulation of one's body organ particularly the liver.
Lastly, Jung and Mindikoglu also found out that fasting can also provide the production of a proteome that decreases the risk of Alzheimer's disease and other cognitive and neuropsychiatric conditions.
Best Fasting Diet To Take
For several years, many studies have already claimed that fasting can actually boost our body's immune system and in general, has numerous benefits for anyone who practices it both in mind and body. However, one must also take extra care and cautions whenever they decide to fast. Some people might gain problems and risk it instead if they have certain medical conditions that might be triggered whenever they refrain or limit their food intake.
In one study published in Cell Journal, prolonged fasting can pose risks to our immune system as compared to a short-term or intermittent fasting diet. When their mice underwent 48-hour fasting, they observed that its immune system suddenly failed to respond properly to heal wounds and stave off infection; resulting in a more serious exposure to bacterias and other pathogens. This study is somehow connected to the human test subject that also underwent fasting and shows a reduction of his monocytes which is a primary defense factor of our body against the entry of harmful microorganisms.
The study also further shows that fasting done for long periods of time can do more damage to the immune system which can lead to an allergic response and metabolic dysfunction. Perhaps this only shows that though fasting can be beneficial, not everyone might be able to harness those benefits and a right fasting diet must also be observed to ensure that it will help our body to become healthier rather than putting it into danger.
As of the moment, the best and the safest way when fasting is to do it intermittently or follow time-restricted eating habits without neglecting liquid intake and to cut down the intake of calorie-rich foods along the way. This is also among the most realistic and practical fasting diets to take especially as we are still in the middle of the COVID-19 pandemic. Dr. Budiningsari, a nutritionist from the University of Gadjah Mada provides some tips to ponder when someone undergoes fasting during this pandemic period we are experiencing today. These are the following:
Take into your diet those foods with fibers and complex carbohydrates like sweet potatoes, beans, wheat bread, and oats which will make you feel full for the long run since our digestive system takes some time to break them down before they are converted to glucose.
Consume healthy foods like vegetables and fruits packed with nutrients to keep you energized. Always ensure that each day you will consume about 2 liters of water or 8 and above glasses of water.
Avoid foods high in trans fat and those with simple carbohydrates such as sweets and soda beverages. Sugar intake must be limited only to 50 grams daily.
Don't overeat yourself after your fasting hour.
One must also be mindful if he or she has a current medical condition that might become active due to restricted eating habits. It is best to see your doctor to guide or monitor you during your fasting period so that you can be sure that you are in good shape even if you change your eating habits.