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Intermittent fasting increases hippocampal neurogenesis in mice
- bitxbitxbitcoin 6y agoI don't know enough about neurobiology to fully understand the graphs beyond the general conclusion in the title. Could someone explain what this tells us about 16 hour vs 24 hour intermittent fasting? Is one "better" than the other?
- frisco 6y agoPer the figures, it looks like 16 hours had the largest effect, even larger than 24 hour fasts. But this is mouse data and should all be taken with a huge grain of salt.
- thangalin 6y ago> taken with a huge grain of salt But only once every 16 hours, apparently.
- voisin 6y agoOff topic: I understand “taken with a grain of salt” is meant to express diminishment of the idea it is being associated with. By saying “huge grain of salt” which is very common, doesn’t that defeat the purpose?
- geforce 6y agoA bit unrelated, but made me remember this study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2995774/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2995774/ The effects of fasting on the human body are... fastinating! (Sorry!)
- netfl0 6y agoI feel like the term intermittent fasting is used by many folks to mean different things. It would be nice if there were more precise terminology here so we could communicate more clearly.
- diydsp 6y agoFrom the fine article: >We evaluated the impact of 3 months of IF (12, 16, and 24 hr of food deprivation on a daily basis)
- rottencupcakes 6y agoSuper interested in how the mice who experienced daily 24 hr food deprivation for 3 months did in the study.
- ei8htyfi5e 6y agoThey eat once a day... so I’m sure they’re fine...
- waihtis 6y agoFun fact: Mice can only survive 48 hours without food, so not eating for 24 hours is quite long for them.
- treeman79 6y agoHad recently gotten two mice. We were upstairs when we realized it was the first ice cold night of the year. So we went down and mice are cuddled in the cold , and apparently out of food. Someone decided fruit loops mixed in with mouse food was a good idea. One mouse went and ate. Other one was clearly in roughed shap. First mouse took a fruit loop, walked it over, and kept putting it against the others mouth. After couple minutes she started eating. The sheer empathy of one mouse helping another still gets to me. They both were fine after eating and being moved to a warm spot.
- eznzt 6y agoWhat determines how long you can survive without food? The speed of your metabolism?
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- chiefalchemist 6y agoCan we get the title updated? This is for rodents.
- Nabati 6y ago16 hours for a mouse is probably equivalent to fasting multiple days for humans.
- auston 6y agoThis! Mice are not quite the same as humans.
- m463 6y agoStatistically speaking we are, except for the long tail...
- deleted 6y ago[deleted]
- hourislate 6y agoA mouse starves to death in 48 hours. I have gone 12 days without food (water fast) and was not even close to starvation. Probably could have gone another few weeks before I expired. I would say 16 hours for a mouse is probably more like 7 plus days without food for a Human.
- api 6y agoHumans can go a long time without food if they are well nourished but can’t go long without water.
- pachico 6y agoI hope you don't mind me asking but why did you fast for 12 days?
- faichai 6y agoMain goal for these kinds of fasts is weight loss, reducing insulin resistance and particularly extended fasts to achieve autophagy where your cells do internal house keeping to clean out broken cellular components and repair themselves.
- lifeisstillgood 6y agoIn mice ...
- ahmedfromtunis 6y agoFor anyone wondering: > Adult hippocampal neurogenesis is a process that describes the generation of new functional DGCs from adult neural stem cells through the amplification of intermediate progenitors and neuroblasts, as well as the integration of these new neurons into the existing neural circuits. Source: https://www.nature.com/articles/s41380-018-0036-2#:~:text=Adult%20hippocampal%20neurogenesis%20is%20a,into%20the%20existing%20neural%20circuits https://www.nature.com/articles/s41380-018-0036-2#:~:text=Ad....
- Icedcool 6y agoOh, well that clears that up. :)
- kitotik 6y ago:/ Anyone care to ELI5 please?
- pkaye 6y agoSeems like a literal translation would be "creation of neurons in the hippocampus". And the hippocampus is associated with memory and learning.
- globular-toast 6y agoIs it good or bad?
- epmaybe 6y agoFasting -> new brain cells and brain connections in a specific part of the brain. At least that’s the correlation they’re going for
- jmcgough 6y agoI worked in a neurogenesis lab for three years, so my attempt: The cells in our body are continuously replaced throughout our life, with the exception of our brain cells. For many many years we believed that mammals didn't create new brains cells in adulthood. You were born, your brain grew and developed as you became an adult, and then you were done. About 20 years ago we realized that that was mostly true, but small parts of the brain continued to produce neurons through adulthood. This happens in two important parts of the brain: - the hippocampus, which is associated with memory - the olfactory bulb, which is associated with sense of smell (and memories related to it). Humans have a relatively weak sense of smell, and if we create new neurons in the olfactory bulb it's much less than other mammals. The process is convoluted, but small regions of the brain create those new neurons and they migrate through fluid-filled holes in your brain - most die, but a small % survive and incorporate themselves into that brain structure. The key thing to realize is that neurogenesis accounts for a tiny fraction of the neurons in our brain, and yet it's still an important process. So why does adult neurogenesis matter, and what does it do for us? Neurogenesis is tied to our ability to learn and form new memories. So, if it's impaired, our ability to learn is reduced. There are tons of things that impact it - age, sleep levels, exercise, among others. In the lab I worked at, we used to induce a form of brain damage to rats which greatly impaired neurogenesis, then run them through mazes, which they did quite poorly at. We took some of those same brain-damaged rats and had them run in exercise wheels for two weeks, and they were suddenly doing just fine at maze tasks. When we stained and looked at their brain, their neurogenesis rate was back up to (or even above) normal levels. We've known for a long time that exercise is great for your health, and there's a growing body of evidence that the same is true for intermittent fasting. What's interesting is that it's not just good for your overall body health, but both can help keep your brain working optimally by increasing neurogenesis and BDNF (which protects your existing neurons).
- johnyzee 6y agoFasting prompts significant release of growth hormone, so it is not surprising that it promotes cell regeneration, but interesting to see it applied to synapses.
- smitty1e 6y agoI find skipping lunch and going breakfast-to-breakfast on Monday and Thursday to be a good rhythm. Being past fifty might play into it. I think about half the USRDA is about right for my caloric intake, though I've never consulted a nutritionist.
- mrfusion 6y agoI fast pretty easily from 6pm to noon the next day. So I would be getting an awesome 18 hour fast daily however I have coffee with milk at 8am. Am I cancelling out those last 4 hours? I hate black coffee so I’m not sure what I could do.
- loceng 6y agoSwitch when you eat. So 8am to 2pm or 4pm eating time.
- baxtr 6y agoThat’s what I did for a long time. But somehow it didn’t feel right. I then switched to 4pm to 8am. Works way better for me now
- mrfusion 6y agoSo early dinner? And then a big breakfast? It’s hard with a family though if they’re on different schedules.
- baxtr 6y agoNo real dinner, just a snack in the afternoon. But yes, breakfast and lunch are a bit heavier. When I think about it, maybe it works better now because of lockdown and WFH...dunno
- mrfusion 6y agoHow do the results for for the different times compare? Is 12 hours seeing a significant effect? What about 16? Disclaimer. I looked at their charts but I didn’t completely understand.
- mrfusion 6y agoHave we looked into whether intermittent fasting prevents Alzheimer’s?
- PicassoCTs 6y agoIm not sure, if what the research here observed is real, stand-alone "neuro" genesis. Several animal species, in times of hardship (like migration) reform their brains, by forgetting unimportant memories or reduce brain area dedicated to now unimportant skills. Quite similar to a stroke victim, that relearns speech, by "re-purposing" a different brain area. Fasting indicates a food scarce environment, so the brain might do the same thing every body does - and reduce calorie consumption in all areas, including the brain. So the "reconnection" might just be a side-effect of the "down-sizing".
- purplerabbit 6y ago“Intermittent” fasting in this context (mice) is more akin to prolonged fasting is humans
- wombatmobile 6y agoIt makes sense that food deprivation stimulates hippocampal neurogenesis, because in the absence of food, a mammal has to go to new locations to find new food sources. That requires navigation and memory mapping, both of which are core functions of the hippocampus. https://journals.physiology.org/doi/full/10.1152/jn.00005.2017 https://journals.physiology.org/doi/full/10.1152/jn.00005.20...
- whatsmyusername 6y agoIf you decide to experiment, add a b-12 supplement. B-12 deficiency will have the opposite effect (as in, you could damage your memory). Seen it happen, it's real not pretty.
- obblekk 6y agoInteresting and lines up with other brain development factors found in human fasting (https://cdnsciencepub.com/doi/abs/10.1139/apnm-2014-0290 https://cdnsciencepub.com/doi/abs/10.1139/apnm-2014-0290). I often read these threads about fasting/intermittent fasting on HN and see a lot of nitpicking about flaws in the study. Given that almost all studies tend to fall between "no effect" or "clear positive effect" of fasting on health, do we have enough evidence to say "fasting is good for your health?" I still believe there's value in further research to nail down exactly how and how much, but curious if we can make the overall statement confidently.
- kilbuz 6y agoDefinitely not. Nutrition and dietary studies are famously hard to draw any solid conclusions from due to the logistical challenges of performing quality studies (randomization, blinding, "placebo" effects, adherence, follow-up, ...). Additionally, do we assume these effects are consistent for everyone, or certain age groups, genetic markers, ethnicities, etc. Even within individuals, would effects be beneficial for the whole lifetime? It seems balance and "do what works for you" would be the recommendation.
- DoreenMichele 6y agoMy opinion: I think it's a qualified "yes." If you can successfully pull it off, there's substantial evidence it is generally beneficial. But I have a genetic disorder that impairs fat processing (so I had no real fat stores to draw on while fasting) and I began fasting or semi fasting while homeless at times when I was too broke to afford food. Initially, it was extremely hard on me. I routinely threw up on fasting days and usually managed to get something into me so was really only light rationed, not actually fasting. It took years for me to get well enough for fasting to stop being horrible torturous drama and I still have extremely severe diarrhea when I resume eating. Second, there is a thing called Refeeding Syndrome that can occur when you break a fast. It can be deadly. I think it benefits a lot of conditions, but if you have a condition, it's also potentially dangerous to try it and we need to get a lot more savvy about how people with conditions can safely try it. With asking around about Refeeding Syndrome and some best practices for how to effectively break a fast plus some experience, breaking a fast has gotten to be a lot easier on me. I could have potentially died from fasting and it likely wouldn't have been blamed on fasting. My condition is serious enough they would have blamed my condition. But it has proven beneficial and I hate it less than I used to.
- yaacov 6y agoCan someone add IN MICE to the title?
- trimbo 6y agoThis needs to happen consistently with paper titles. There's a Twitter account is dedicated to it: https://twitter.com/justsaysinmice https://twitter.com/justsaysinmice
- dang 6y agoYes. Added.
- tonyedgecombe 6y agoWe are going to end up with the healthiest mice the world has ever seen.
- m463 6y agokind of like "peace through war"
- aitchnyu 6y agoI would buy a book about big health announcements dying in a corner since mice trials didnt replicate to humans.
- andreygrehov 6y agoEvery time I see a research being published on HN, it ends up being a mouse model. Is there a place on the internet where I can see a list of publications describing the final (or close to final) stage of a research made on humans? Mouse model researches worsen my overall abstraction of where the humanity, in a scientific sense, is.
- romanoderoma 6y agoI think this answer might interest you https://news.ycombinator.com/item?id=24953724 https://news.ycombinator.com/item?id=24953724
- Ninjinka 6y agoDiet restriction (with maintaining the required nutrients) is also key to living longer
- DyslexicAtheist 6y agoMost people (especially those who have built up some "reserves") can survive for a long time without food and would safely last months on just liquid. (treated water or herbal tea + some vitamins & minerals). I did a water only fast which is documented here: https://news.ycombinator.com/item?id=16533514 https://news.ycombinator.com/item?id=16533514 The mental benefits in terms of ability to concentrate are hard to put into words. It's different than with micro-dosing which gives you a false sense of your abilities. The long fast showed me what kind of energy gets unlocked when we feel like we're close to snuffing it. It's like the body gets ready for a final push so that you can hunt and find food. I stopped doing these crazy type of diets after discovering IF. IF gives me a similar result (the highs and lows on the graph are less extreme but at least it's sustainable) without landing myself in hospital (in retrospect the kidney stones were most likely legacy/cruft that needed to be refactored anyway, and who knows what kind of cancers or other long term illnesses my body "ate" while I pushed him that hard). I understand this is all pretty mental to read but back in 2013 there was no IF and all I had was the theory that dogs and rats that were kept on an IF survived longer. !!! Disclaimer: this is the most extreme one I ever done so please don't start out with this if you want to try... try 7 days or 2 weeks are enough time to do some extreme diet. But don't go overboard - which is way too easy after 2 weeks because you'll be so high on your own achievement and you won't feel hunger. It'll feel like you're able to continue for 2 or 3 months. (you won't). the key is in recognizing this and to quit regardless! Also knowing your own body is key. E.g. if you do sports and have a 20 year history of pushing yourself to extremes probably yes. But I understand why doctors bail and give the "blanket advise" that this is irresponsible. !!!
- acituan 6y agoDetails to pay attention to; - It is not stated if the diets are isocaloric or hypocaloric; probably because it wasn't measured. Timing restrictions and calorie restrictions are two different stressors on the body, and all else being equal stress is positively correlated with neurodegenerative effects. It might as well be only isocaloric intermittent fasting is indicative of BDNF increase and hippocampal neurogenesis. - Fasting time is a very specific slice of the circadian rhythm; between 15:00–07:00, so this study is only skipping dinner and not breakfast. This is important because body has different stress responses early in the morning (we wake up with higher cortisol levels) and our insulin mechanism also reacts differently to food deprivation based on time of the day. - Limits of animal models already mentioned, and I think it is particularly compounded around the concerns around timing and bioeconomics of growing brain regions. Mice and humans have similar encephalization quotients, but size of neural cells are constant between both, so is the cost to create or upkeep them. Same concern goes for the number of days of energy each animals bodies can store. So the underlying calculus to make new brain cells or not might be vastly different. For example maybe humans need to undergo a much longer (e.g. multiday) fast before this effect kicks in.
- faeyanpiraat 6y ago"stress is positively correlated with neurodegenerative effects" Can you provide some references to this?
- SenorTibbs 6y ago[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4806285/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4806285/ [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3196277/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3196277/
- antpls 6y agoAlso, is the diversity of metabolism found in humans taken into account? Some humans are 50kg, others are 100kg. Some are naturally skinnier, some are fatter. Surely it must have an impact on fasting rythmes too.
- 1e-9 6y agoIn previous rodent studies, intermittent fasting (IF) was found to stimulate production of neural stem cells in the hippocampus, which is a portion of the brain critical to memory formation. This study measured apparent IF-induced changes in a particular type of molecular communication (the Notch signaling pathway) that the body uses to tell itself to increase such stem cell production.
- elevenoh 6y agoAnyone else here do a semi intermittent fast, e.g. only eating something like cocoa/dark chocolate throughout the day + having 1 meal/day? Seems to get some portion of the benefits.
- ketamine__ 6y agoSo does NSI-189? https://en.wikipedia.org/wiki/NSI-189 https://en.wikipedia.org/wiki/NSI-189
- m3kw9 6y agoThey considered 12hr a fast. So finishing dinner at around 7 and eating at 7am next day is considered a fast? Easier than I thought about what a fast would be like
- _wldu 6y agoYes, It is. It's so common, in fact, that it has a name... breakfast. Break the fast.
- jml7c5 6y agoVery important to note that the non-fasting mice were significantly less heavy: >Compared to AL [ad libitum, "at one's pleasure"] mice, IF12 [12 hour fast], IF16 [16 hour fast], and EOD [24 hour fast] tamice demonstrated significantly lower average body weight after 3 months of IF (Data not shown). So this could be due to lower overall caloric intake.