A diet that is restricted can apparently help the immune system combat cancer.
A new mouse study shows that fasting effectively reprogrammed the metabolism of some white cells responsible for killing tumors.
Immune System Fighting Cancer
A global team led by researchers at the Memorial Sloan Kettering Cancer Center examined white blood cells known as NK cells (natural killer cells) among the mice.
The immune system makes use of such cells to handle threats to the body. These threats include viruses and cancer.
Unlike T-cells that seek antigens, NK cells can destroy threats that they did not encounter in the past. If the body can direct such immune cells more toward a tumor, chances of survival go up.
However, when it comes to cancer, NK cells face a lot of stress.
How Fasting Could Help the Immune System
Joseph Sun, an immunologist from the center, explained that tumors are extremely hungry. These tumors take in important nutrients, fostering an environment that is hostile and that is rich in lipids that pose dangers to the majority of immune cells.
What is seen here is that fasting could reprogram such NK cells to survive better in an environment that is suppressive.
As part of the study, the mice got injected with tumor cells and were given a diet where they had the freedom to eat. This was apart from two different 24-hour periods of fasting (water-only) for every week.
This was noted in the "Fasting reshapes tissue-specific niches to improve NK cell-mediated anti-tumor immunity" study.
Weight loss was generally not observed. However, blood glucose levels did drop. This triggered a free fatty acid rise. These fatty acids are an alternative energy source that the NK cells can tap.
The mice's NK cells were also observed to adapt. They made use of the free fatty acids as an energy source, rather than glucose.
It was like they had reinforcements or better training against the tumor through extra cytokine production. Cytokines are proteins that instruct the immune system to go on with its job.
NK cells were also redistributed across the body. Several reached the bone marrow, where they were exposed to high interleukin-12 levels. Such a protein results in a biological reaction that could help fight cancer further.
Putting both mechanisms together enabled the researchers to find that NK cells have been pre-primed to make more cytokines in the tumor. This was noted by Rebecca Delconte, an immunologist from the center.
Moreover, with metabolic reprogramming, these could survive within the environment of the tumor. They are also specialized to have boosted some anti-cancer properties.
However, the authors note that fasting regimes should only be commenced after seeing a doctor first. This is because what is healthy for one individual may not be healthy for another.
The research is also still in its infancy stage, requiring further verification. There are various questions that still need to be answered, like whether or not every NK cell goes through these retraining across their lifespan.
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