Do Diets That Mimic Fasting Improve The Immune System?

This research is demonstrating that cycles of fasting or fasting mimicking diets followed by refeeding a normal diet promotes stem cell dependent rejuvenation of the immune system in old mice. Early clinical trials show this process of cleaning up older white blood cells during a short period of fasting promoting restoration of normal levels of infection fighting cells when fasting is stopped may also occur in humans to provide potential health benefits. 

These findings support clinical trials to investigate whether they will be effective in improving immune system function in elderly population without detrimental side effects and increasing vaccination efficacy in older adults; and according to Longo upcoming trials will examine the fasting mimicking diet’s effect on flu, and if funded when it becomes available, coronavirus vaccination in humans.

"We want to see if certain dietary interventions that can make a virus less infectious or cause fewer negative effects," Longo says.

Due to immunosenescence vaccine efficacy and strengthening the immune system is important to older adults, which is the gradual decline of immune system function and with it comes the increased risk of serious complications from viral infections. 

Previous trials of a fasting mimicking diet demonstrated decreased cardiovascular disease risk factors as well as fasting glucose and reduced levels of IGF-1, and shrinking waistlines that resulted in weight loss in total body fat and total trunk fat but not muscle mass. The fasting mimicking diet also appeared to sensitize cancer cells to chemotherapy and lessen the treatment side effects in those with cancer. 

Those involved in the trial were placed on special diet and required them to eat foods that were supplied by L-Nutra during the fasting periods of 5 days per each month; the diet was designed to mimic the results of a water only fasting period that allowed for participants to consume between 750-1,100 calories each day with the meals containing precise proportions of fats, proteins, and carbs. 

Longo cautions that even though the results are very promising any kind of fasting or fasting mimicking diet should only be undertaken after consulting with a physician and followed under that guidance, especially for those that have been diagnosed or are suspected to have a disease. 

The current state of affairs having shelter in place and stay at home orders may provided an opportunity for those who are overweight or gaining weight to try this diet plan, but it is important that in the face of this potential illness it is key for everyone to stay well nourished in general, especially for those that have been deemed as essential workers who are the highest risk for possible exposure to this novel COVID-19 virus.

During this pandemic Longo encourages everyone to follow a healthy balanced diet like the Mediterranean diet versus a long term restrictive low calorie diet, as the immune system can get depressed with a poor diet or one that is too restrictive and put you at an increased risk of infection. "This is not the time to push yourself to the limit,” warns Longo.