Caloric restriction increases lifespan but affects brain integrity in lemurs

When you say "mostly optional" I assume you mean working out will drastically reduce the rate of muscle loss. Is that what you mean or are there other intervention?

bigDinosaur• 4 years ago

I've seen it unironically cited in psychology textbooks as a 'benefit' to dementia that you become increasingly unaware of just how much you've lost. It's not totally untrue I suppose, so I can see the angle, but it's also clearly the copest of copes.

One major reason to be aware of decline is so you can plan. That may include long term care or obviously more dramatic measures. It creates a gigantic set of issues for families when someone declines who had no plan at all and is in denial or unable to understand their own decline.

PicassoCTs• 4 years ago

Eh, that seems to be only partially true. You are forever aware of the feeling of location loss, positional unawareness. You wake up every minute, in a strange city, strange place, with strange people. Normal reaction to that is stress and panic. Which is why you get medicated against fear and stress as dementia patient.

fwungy2• 4 years ago

Best treatment for a cold is lots non-caloric fluids and fasting. It works by letting your body put its energy into healing instead of digestion.

Stop eating 3-4 hours before bedtime to improve sleep. Same principle.

nradov3• 4 years ago

Is there any clinical research showing that fasting reduces duration of cold symptoms?

pengaru• 4 years ago

Not OP, but prolonged fasting is well understood to significantly affect the immune system.

I doubt not eating for a single day while fighting a cold is going to matter though, especially if sedentary/sick in bed.

During a prolonged fast you'll be decreasing white blood cells, which doesn't seem ideal if you're already sick. But AIUI it's mainly this aspect that "reboots the immune system", and can prevent illness once feeding has resumed and the catabolism undone. Basically you get a refreshed immune system, afterwards:

“When you starve, the system tries to save energy, and one of the things it can do to save energy is to recycle a lot of the immune cells that are not needed, especially those that may be damaged,” Longo said. “What we started noticing in both our human work and animal work is that the white blood cell count goes down with prolonged fasting. Then when you re-feed, the blood cells come back. So we started thinking, well, where does it come from?” [0]

[0] https://news.usc.edu/63669/fasting-triggers-stem-cell-regene...

wdroz• 4 years ago

There are some research on mice[0] with the ketogenic diet (usually you go in ketosis state if you are fasting).

[0] -- Ketogenic diet activates protective γδ T cell responses against influenza virus infection https://www.science.org/doi/abs/10.1126/sciimmunol.aav2026

N3cr0ph4g1st• 4 years ago

Is stopping eating 3-4 hours really legit or just some traditional thought we've heard over and over again that sounded intuitive that we've come to accept? Lots of cultures that are long lived have late night meals and from a quick NCBI search, I found that even the old perceptions are getting proven wrong. Example:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4425165/

fwungy2• 4 years ago

Try it with biostatistics device both ways. You will see your resting heart rate is substantially lower when you stop eating early, and this will improve your HRV and deep sleep stats.

whywhywhydude• 4 years ago

“without affecting cognitive performances” - does that mean calorie restriction makes brain even more efficient by pruning unneeded parts?

jesuscript• 4 years ago

Less calories means less energy, which means you have to use the energy you do have more optimally. If there was no impact on cognitive performance, then all that means is you spent extra energy before doing stuff that didn't require the excess energy.

A good example might be overthinking. Some of our lives and jobs are much simpler than we realize.

pessimizer• 4 years ago

Some of our lives and jobs are much simpler than we realize.

Based on the output of deep learning models, most of our lives and jobs probably don't even require sentience.

makeitdouble2• 4 years ago

They are assessing cognitive performance with a single test, and these lemur have a special ‘low energy’ mode, so there’s many options. For instance it might be that their single test succeeds while other brain capacities are impacted (for instance social, emotionally capacities or memory).

nradov3• 4 years ago

Caloric restriction has never been shown to increase lifespan in large primates. And the experiments showing increased lifespan in lower animals have been highly artificial with the subjects protected from infections and injuries. Caloric restriction in elderly people causes sarcopenia, which greatly increases the risk of disabling orthopedic injuries.

TylerLives• 4 years ago

I wonder if some of the benefits come not from caloric restriction itself but reduction of something else that's harmful.

Regenerative healing also requires freedom from substances that inhibit the digestion of the debris. The great decline in proteolytic autophagy that occurs with aging (Del Roso, et al., 2003) can be reduced by inhibiting the release of fatty acids. This effect is additive to the antiaging effects of calorie restriction, suggesting that it is largely the decrease of dietary fats that makes calorie restriction effective (Donati, et al., 2004, 2008)[0]

[0] https://raypeat.com/articles/articles/regeneration-degenerat...

adrian_b• 4 years ago

While most experiments done until now have investigated the effect of calorie restriction, there have also been some more specific experiments.

Some experiments have obtained similar lifespan extension by protein intake restriction, not by energy intake restriction. A few other experiments have obtained the same effect by restricting only the methionine intake.

Methionine is required for the initiation of the synthesis of any protein. When it is insufficient, the rate of protein synthesis slows down everywhere in the body.

Assuming that all these experimental results are correct and that they have a more general applicability than for the few tested animals, then it appears that the lifespan extension is achieved by slowing down the rate of protein synthesis.

This might work by preventing an unnecessary recycling of the body components, which eventually accumulates defects. Nevertheless, in the case of injuries or illness, a reduced rate of protein synthesis is very undesirable.

It is likely that in big or long-lived animals the rate of protein synthesis is already diminished and close to the minimum acceptable, because such animals have lower energy intake per mass needs (even when comparing poikilotherms).

This would explain why such lifespan extension methods do not seem to work in big animals. It is likely that they have low or no effect in humans too.

eternityforest• 4 years ago

I wonder if there's a benefit to eating precisely the amount of calories needed to prevent notable muscle loss with as little surplus as possible, or to CR in the young that you stop when you're older?

nradov3• 4 years ago

It's very difficult for elderly people to build and maintain lean muscle mass because the endocrine and digestive systems become less effective with age. After about age 70, progressive muscle loss is unavoidable (at least without heavy use of performance enhancing drugs which cause other negative side effects). So, if you want to live a long life without falling down the stairs and breaking a hip when you're 80 then you need to build up some extra muscle when you're young. That means eating a relatively high protein diet (but not a caloric surplus unless you're underweight).

ekianjo• 4 years ago

.. in mice. Always great when people do not edit the title...

dang2• 4 years ago

There isn't room for the full title because HN's titles are limited to 80 chars. There's room for us to inmice it though!

mrosett• 4 years ago

In this case I believe it's in (confusingly named) lemurs.

jb1991• 4 years ago

This study did not involve mice.

makeitdouble2• 4 years ago

I'm a bit lost. In a different study [0](also playing with food restrictions) there is mention of torpor, a mechanism that these lemurs have that kicks in under calorie restriction and changes their metabolism and body composition.

Yet from the article

but the effects in humans and other primates remain controversial

If these lemurs have specific energy mechanisms proper to their species and adapted to their ecosystem, does any conclusion extend to humans and other species ?

[0] https://journals.plos.org/plosone/article?id=10.1371/journal...

rTX5CMRXIfFG• 4 years ago

Can’t draw conclusions unless the subjects themselves are humans, and unless the studies have replicable results. It’s either that or everything is mere speculation.

Caloric restriction increases lifespan but affects brain integrity in lemurs

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