Posted on 10/27/2021 1:05:58 PM PDT by nickcarraway
A new study finds cutting off cells’ supplies of lipids can slow the growth of tumors in mice.
In recent years, there has been some evidence that dietary interventions can help to slow the growth of tumors. A new study from MIT, which analyzed two different diets in mice, reveals how those diets affect cancer cells, and offers an explanation for why restricting calories may slow tumor growth.
The study examined the effects of a calorically restricted diet and a ketogenic diet in mice with pancreatic tumors. While both of these diets reduce the amount of sugar available to tumors, the researchers found that only the calorically restricted diet reduced the availability of fatty acids, and this was linked to a slowdown in tumor growth.
The findings do not suggest that cancer patients should try to follow either of these diets, the researchers say. Instead, they believe the findings warrant further study to determine how dietary interventions might be combined with existing or emerging drugs to help patients with cancer.
“There’s a lot of evidence that diet can affect how fast your cancer progresses, but this is not a cure,” says Matthew Vander Heiden, director of MIT’s Koch Institute for Integrative Cancer Research and the senior author of the study. “While the findings are provocative, further study is needed, and individual patients should talk to their doctor about the right dietary interventions for their cancer.”
MIT postdoc Evan Lien is the lead author of the paper, which was published on October 20, 2021, in Nature.
Metabolic mechanism Vander Heiden, who is also a medical oncologist at Dana-Farber Cancer Institute, says his patients often ask him about the potential benefits of various diets, but there is not enough scientific evidence available to offer any definitive advice. Many of the dietary questions that patients have focus on either a calorie-restricted diet, which reduces calorie consumption by 25 to 50 percent, or a ketogenic diet, which is low in carbohydrates and high in fat and protein.
Previous studies have suggested that a calorically restricted diet might slow tumor growth in some contexts, and such a diet has been shown to extend lifespan in mice and many other animal species. A smaller number of studies exploring the effects of a ketogenic diet on cancer have produced inconclusive results.
“A lot of the advice or cultural fads that are out there aren’t necessarily always based on very good science,” Lien says. “It seemed like there was an opportunity, especially with our understanding of cancer metabolism having evolved so much over the past 10 years or so, that we could take some of the biochemical principles that we’ve learned and apply those concepts to understanding this complex question.”
Cancer cells consume a great deal of glucose, so some scientists had hypothesized that either the ketogenic diet or calorie restriction might slow tumor growth by reducing the amount of glucose available. However, the MIT team’s initial experiments in mice with pancreatic tumors showed that calorie restriction has a much greater effect on tumor growth than the ketogenic diet, so the researchers suspected that glucose levels were not playing a major role in the slowdown.
To dig deeper into the mechanism, the researchers analyzed tumor growth and nutrient concentration in mice with pancreatic tumors, which were fed either a normal, ketogenic, or calorie-restricted diet. In both the ketogenic and calorie-restricted mice, glucose levels went down. In the calorie-restricted mice, lipid levels also went down, but in mice on the ketogenic diet, they went up.
Lipid shortages impair tumor growth because cancer cells need lipids to construct their cell membranes. Normally, when lipids aren’t available in a tissue, cells can make their own. As part of this process, they need to maintain the right balance of saturated and unsaturated fatty acids, which requires an enzyme called stearoyl-CoA desaturase (SCD). This enzyme is responsible for converting saturated fatty acids into unsaturated fatty acids.
Both calorie-restricted and ketogenic diets reduce SCD activity, but mice on the ketogenic diet had lipids available to them from their diet, so they didn’t need to use SCD. Mice on the calorie-restricted diet, however, couldn’t get fatty acids from their diet or produce their own. In these mice, tumor growth slowed significantly, compared to mice on the ketogenic diet.
“Not only does caloric restriction starve tumors of lipids, it also impairs the process that allows them to adapt to it. That combination is really contributing to the inhibition of tumor growth,” Lien says.
Dietary effects In addition to their mouse research, the researchers also looked at some human data. Working with Brian Wolpin, an oncologist at Dana-Farber Cancer Institute and an author of the paper, the team obtained data from a large cohort study that allowed them to analyze the relationship between dietary patterns and survival times in pancreatic cancer patients. From that study, the researchers found that the type of fat consumed appears to influence how patients on a low-sugar diet fare after a pancreatic cancer diagnosis, although the data are not complete enough to draw any conclusions about the effect of diet, the researchers say.
Although this study showed that calorie restriction has beneficial effects in mice, the researchers say they do not recommend that cancer patients follow a calorie-restricted diet, which is difficult to maintain and can have harmful side effects. However, they believe that cancer cells’ dependence on the availability of unsaturated fatty acids could be exploited to develop drugs that might help slow tumor growth.
One possible therapeutic strategy could be inhibition of the SCD enzyme, which would cut off tumor cells’ ability to produce unsaturated fatty acids.
“The purpose of these studies isn’t necessarily to recommend a diet, but it’s to really understand the underlying biology,” Lien says. “They provide some sense of the mechanisms of how these diets work, and that can lead to rational ideas on how we might mimic those situations for cancer therapy.”
The researchers now plan to study how diets with a variety of fat sources — including plant or animal-based fats with defined differences in saturated, monounsaturated, and polyunsaturated fatty acid content — alter tumor fatty acid metabolism and the ratio of unsaturated to saturated fatty acids.
Reference: “Low glycaemic diets alter lipid metabolism to influence tumour growth” by Evan C. Lien, Anna M. Westermark, Yin Zhang, Chen Yuan, Zhaoqi Li, Allison N. Lau, Kiera M. Sapp, Brian M. Wolpin and Matthew G. Vander Heiden, 20 October 2021, Nature. DOI: 10.1038/s41586-021-04049-2
The research was funded by the Damon Runyon Cancer Research Foundation, the National Institutes of Health, the Lustgarten Foundation, the Dana-Farber Cancer Institute Hale Family Center for Pancreatic Cancer Research, Stand Up to Cancer, the Pancreatic Cancer Action Network, the Noble Effort Fund, the Wexler Family Fund, Promises for Purple, the Bob Parsons Fund, the Emerald Foundation, the Howard Hughes Medical Institute, the MIT Center for Precision Cancer Medicine, and the Ludwig Center at MIT.
Interesting....My cancer showed up after several years of working major proposals and extended hours, where the junk food was free and abundant.
If someone loses weight without explanation, it’s often cancer.
The cancer eats the food you eat and starves the patient so he loses muscle and fat.
Cutting calories will starve the tumor, but also starve the patient worse than he’s already being starved.
If you starve the patient to death, you will surely kill the cancer.
Everybody’s got opinions
but nobody’s got the answers
and the sh*t you ate for breakfast
well it’ll only give ya cancer
as someone else just posted in another thread, on a similar topic, most americans spend their lives digging their graves with their mouths.
I am as guilty as the next guy, but I try.
Yes, there are those lucky few that smoke 3 packs a day, drink like an alcoholic, never exercise or eat a vegetable, and somehow defy the odds, but they are mostly the exception.
My father is a perfect example - thought he would be dead 30+ years ago with the life he lived. Alcoholic, 2-3 packs a day, never saw him break a sweat (except perhaps running from a jealous husband), would come home at 2AM from the bars and head back out to work at 5AM for years on end....and yet, at 86 it is just starting to catch up with him....guess the the Marines made him tough.
It’s been known for a long time that cancers feed on sugars.
We could all eat the Soros/PeeLousy diet of gray paste made out of ground baby and live forever
Because if it was, we couldn't make any money off it!
I had to chuckle a little when I read that.
I have a 94 year uncle who is in hospice as I write. No, that is not what is bringing a chuckle. Its not really a secret to anyone including him how this is going to end. And he is OK.
What brought the chuckle is this guy hasn’t had anything to eat or drink since last Thursday. His stroke prevents him from swallowing. His final wishes are being respected in terms of feeding and IV fluids—again, everyone is cool with that.
Whats funny is this tough old guy tells me he still hasn’t had anything to drink for X days when I go visit him. Not thirsty yet, he tells me.
I’ve been with a lot of elder relatives (my wife is the only grandkid in family with eight aunts and uncles.) None of them bragged about what was going on...right up to the end.
In 2017, I had a grapefuit-sized pseudo-cyst tumor on my pancreas, and for 23 days, was fed in both neck veins with nutrients and saline; no food. I had 5 cubes of ice chips a day. I had 15 ERCP Endoscopies to set 4 pigtail drains to drain the cyst, and am still here today.
Zero carbs, sugar, calories, and I lost 135lbs — down from 265 to 131 — and had to use a piece of rope from maint dept to tie my 38” jeans to my 31” wait, just to get discharged. (I could have stuffed 2 nurses in there!) Heh. I’m 165lbs now and doing fine. No more insulin; back to Type 2 diabetes w/ metformin and Jardiance.
Thank the Lord, nurses and Drs at PSU-Hershey Med Ctr Hospital..
“What You Eat Affects Tumors: Diet May Slow Cancer Growth”
well,yeah.
This is somehow news? Cutting edge science?
My Grandmother told us that. She must have been a closet Rocket Scientist.
/s
So we should now eat mice to live longer? The rats are running the looney bin!
“Thank the Lord, nurses and Drs at PSU-HERSHEY Med Ctr Hospital..”
HERSHEY!? Love their chocolate!
I used to eat it by the lb, every week, before diabetes. GREAT MILK CHOCOLATE.
Hmmm... I read somewhere that cancer was a strict vegan. How does that fit with claims made in the article? /s
...and in 2021, the death will be attributed to Covid.
Hey Friend, those who lived through the Depression and WW2 are freaking geniuses, whether they ever received any diplomas or degrees.
Cancer doesn’t just eat the food you eat, it is greedy. It eats nutrients at a very high rate, and this is the trick. If a person fasts, their metabolism slows so they burn fewer calories. But cancer doesn’t slow. Its only response to starvation is to starve to death.
Funny, “This is the diet that works BUT DON’T DO THIS YOURSELF! We are gonna make some DRUGS to help you!” I’ll be surprised if I take anything other than basic painkiller or antibiotic again after this covid crap
If you see me heading to Dairy Queen, you will know that I have something serious and officially off my low-carb diet.
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