"Starving cancer cells" adds new evidence! Reasonable fasting may improve anti-tumor efficacy

As the saying goes: "Man is iron, rice is steel, and a meal is not eaten and hungry is panicked." This is still the case for healthy people, so for cancer patients, a nutritious diet and a regular lifestyle are extremely important. But some patients do the opposite, trying to destroy tumor cells by starving, believing that as long as they eat less nutritious things, they can "starve" tumor cells. Is this really the case?

Is "hunger therapy" reliable?

In fact, even if the patient does not eat or drink, the tumor cells will still plunder the nutrients of the human body for their own growth, and will not be "starved to death", while the patient will be due to lack of nutrition, reduced immunity, affecting the treatment effect. Therefore, hunger tends to make the patient's physical energy depletion faster and accelerate the deterioration of the disease. Therefore, the practice of blindly not eating nutrients is harmful and has no benefit.

However, it is not entirely impossible to "starve" tumor cells, in fact, researchers are indeed exploring ways to "starve" tumors. For example, anti-angiogenic drugs cut off the "food transport channel" of tumors by inhibiting the generation of tumor blood vessels. For patients themselves, there is also a new dietary model that helps with anti-tumor treatment, which is the "simulated fasting diet". The "fasting-mimicking diet" (FMD), as the name suggests, is a way of eating that simulates a state of fasting.

In fact, as early as the "Yellow Emperor's Inner Classic" there are relevant records about "hunger therapy", in recent years, in-depth research has found that simulated fasting diet can reverse diabetes symptoms, prevent the impact of high-fat, high-calorie diet on cardiac metabolism and lifespan, reduce the risk of aging-related diseases, such as cardiovascular and cerebrovascular diseases, cancer, etc., and increase the effect of cancer treatment.

If simulated fasting diets can really improve the internal environment of tumor patients and increase the immune function of patients, then this easy-to-operate and health-promoting way is simply of landmark medical value.

Recently, the results of the first human clinical trial on simulated fasting diets were published in the journal Cancer Discovery1. This study confirms for the first time the safety and efficacy of a diet regimen with strict short-term calorie restrictions for cancer patients. Let's take a look at the magic of it.

Exploration of preclinical research

A simulated fasting diet is a five-day, low-calorie diet. It puts the body into a state of fasting without feeling too hungry and reaping the benefits of fasting. Past studies have found that simulated fasting diets can reduce growth factor levels, such as insulin and insulin-like growth factor 1 (IGF-1), and reduce peripheral blood immunosuppressive cells, increase T cell infiltration within tumors, improve immune function in patients, and promote metabolism in the body. A possible explanation for this miraculous effect is that starvation allows cells in the body to deplete themselves, helping to clear senescent discarded cells and organelles.

A series of preclinical studies have confirmed that simulated fasting diets that strictly limit caloric intake, combined with standard drug therapy, can produce effective anti-cancer effects. However, to date, there have been few clinical studies on the safety and efficacy of calorie restriction in cancer patients.

How does the simulated fasting diet work?

The study enrolled 101 oncology patients who received different standard regimens and who were combined with a fasting simulated diet regimen. The regimen includes a five-day low-carbohydrate, low-protein, plant-based diet. Provide 600 kcal of calories on day 1 and 300 kcal per day on days 2, 3, 4, and 5, i.e. a total of 1,800 calories in five days. Repeat every three or four weeks for up to eight consecutive cycles. The other 16 to 23 days of a cycle are the nutritional phase, during which the patient's diet can follow healthy eating and lifestyle guidelines, without specific dietary restrictions.

Results of a simulated fasting diet study

1. Safe and controllable

As of now, patient compliance is 91.8%, and the study has reached its primary safety endpoint. The incidence of seriously related adverse events was 12.9%, with fatigue symptoms most common. This suggests that regardless of tumor type and treatment regimen, short-term strict calorie restriction is safe and feasible and well tolerated for most patients. At the same time, the study found that the weight loss that most patients experienced within five days of severe caloric restriction after re-eating was reversible, ruling out the risk that patients might experience progressive weight loss or malnutrition.

2. Metabolic and immune changes that are beneficial to anti-tumor

At the same time, the researchers evaluated the effects of a simulated fasting diet on the patient's metabolic and immune responses. In 99 assessable patients, the simulated fasting regimen reduced median plasma glucose concentration by 18.6%, serum insulin by 50.7%, serum IGF-1 by 30.3%, and remained stable over eight consecutive cycles. This result confirms the conclusion in the preclinical model that causes a decrease in blood glucose and growth factors, which will effectively enhance the anti-tumor effect.

At the end of a five-day simulated fasting diet cycle, another analysis of 38 patients by the researchers found a significant decrease in circulating immunosuppressive myeloid cells and an increase in activated CD8+ T cells. This phenomenon may be related to severe calorie restriction producing metabolic 'shock' and activating immune cell populations, which will enhance the antitumor activity of standard treatment regimens.

brief summary

The study, which combined a simulated fasting diet with standard anti-tumor treatment, confirmed the safety and biological effects of a simulated fasting diet. Simulating a fasting diet can not only cause metabolic changes in blood glucose and growth factor reduction, but also promote the increase of peripheral blood immunosuppressive myeloid cells and regulatory T cells, reshape anti-cancer immunity, and enhance the anti-tumor efficacy combined with standard anti-tumor therapy.

It is worth noting that although the simulated fasting diet is beneficial for tumor treatment, this is completely different from the way some patients think that blind fasting is used to "starve the tumor". This dietary pattern is somewhat complicated and needs to be carried out under the guidance of scientific and professional medicine, and it is not recommended that patients try this method on their own without the permission of a doctor, so as not to affect the normal treatment effect.

It is hoped that the next exploration will further confirm the significance of calorie restriction for tumor treatment, improve the efficacy of anti-tumor therapy, and benefit every patient.

参考文献：1. Vernieri, C. et al. Fasting-mimicking diet is safe and reshapes metabolism and antitumor immunity in cancer patients. Cancer Discov candisc.0030.2021 (2021) doi:10.1158/2159-8290.CD-21-0030.