"Nature" is heavy: this diet can limit tumor growth!

▎ WuXi AppTec content team editor As a medical oncologist at the Dana-Farber Cancer Institute, Professor Vander Heiden often receives questions from cancer patients about food: "Which diet is good for the body?" Although The evidence is not clear enough, but there are already some data suggesting that there are two diets that seem to be good for cancer patients, namely calorie restriction (reducing calorie intake by 25%-50%) and a ketogenic diet (low carbohydrate, high fat, and high protein).
), they can keep the peak of blood sugar level and insulin level at a low level, and some animal experiments show that these two methods are related to tumor growth inhibition
.

 Image source: 123RF With the new understanding of cancer metabolism in the scientific community in the past 10 years, a group of MIT scientists decided to re-understand the relationship between diet and tumors.
According to their research published in Nature today, they may be able to truly inhibit tumors.
The growth is calorie restriction, not a ketogenic diet
.

 In the past, tumor metabolists believed that a low-carb diet can affect tumors, mainly because cancer cells consume a lot of glucose
.

In the new study, Professor Heiden and colleagues set up three groups in the tumor mouse model: normal diet, ketogenic diet, and calorie restriction
.

Preliminary results showed that only the mice in the calorie restriction group showed a significant slowdown in tumor growth
.

 ▲Only calorie restriction (CR) can delay the growth of tumors.
The ketogenic diet (KD) mice are almost the same as the control (picture source: reference [1]).
Specifically, compared with the normal diet, there are two types of special diets All methods will cause the mice's glucose level to drop
.

But the difference is that the lipid level of mice in the calorie restriction group also decreased, while the lipid level of mice in the ketogenic diet did not decrease but increased.

.

 It is such a small difference, but the difference reflected in the final result is huge
.

The researchers pointed out that it seems that lipids have a greater impact on slowing tumor growth, while glucose is not so important
.

 They believe that lipids play an important role in the construction of cell membrane systems
.

Under normal circumstances, if the lipids are not sufficient, the cells can produce the required amount by themselves
.

This requires cells to maintain a very delicate balance, that is, to control the amount of saturated fatty acids and unsaturated fatty acids.
Stearoyl-CoA desaturase (SCD) plays a key role in it.
It can convert saturated fatty acids into unsaturated fatty acids.
Fatty acids
.

 Image source: Follow-up analysis by 123RF showed that the activity of SCD in the calorie restriction group has decreased, which caused the tumor cells to not obtain unsaturated fatty acids well, so the lipid supply was impaired and the growth rate would slow down
.

"Caloric restriction will not only starve the tumor, they will break the curve idea of self-help, it is a double benefit
.
"
The main author of the study, Dr.
Evan Lien expressed
.

 In fact, the SCD activity of the mice in the ketogenic diet group also decreased, but the diet itself contains a lot of lipids, even without SCD, it cannot prevent the tumors from obtaining lipids, so the tumors can still grow unscrupulously
.

 ▲Professor Vander Heiden (picture source: personal homepage of the school’s official website) This discovery provides more interesting directions for future tumor therapies.
For example, creating a drug to prevent tumor cells from obtaining unsaturated fatty acids may delay tumor growth
.

Or there is a way to prevent the function of SCD, it is also possible to achieve the above effect
.

 However, the researchers cautiously emphasized that this study is only an exploration of the physiological mechanism, not to provide dietary formulas for cancer patients
.

The study additionally analyzed data from some large human cohort studies.
They found that pancreatic cancer patients started to follow a low-carb water diet after diagnosis, but the type of fat intake actually correlated with the patient’s length of life, such as low-carb water, vegetable protein, and fat.
Diet is associated with longer survival
.

 It is worth noting that these data reflect only correlation
.

Researchers claim that the current evidence is not enough to draw conclusions about the relationship between diet and cancer control
.

They plan to perform a refined analysis of the types of lipids in the diet to determine the effects of different components on tumors
.

 Reference: [1] Evan C.
Lien, et al.
Low glycaemic diets alter lipid metabolism to influence tumour growth.
Nature (2021), DOI:10.
1038/s41586-021-04049-2[2] How diet affects tumors.
Retrieved Oct 20, 2021 from https://