Interesting new insight on intermittent fasting

I've been a bit distracted and so haven't posted in a while.  I do hope everyone had a wonderful Christmas, Hanukkah, or whatever you celebrate.  This is a season of light and hope.

I have come across news on intermittent fasting that I thought was interesting.  It has to do with the gut-brain axis.  We've written before about the influence of the gut-brain axis on brain health.  Somehow, there is a two-way communication between microbes in the gut (bacteria and archaea) that regulates brain function.  Meaning that healthy gut = healthy brain.  Or something like that.

When we discussed intermittent fasting in Beating the Dementia Monster, it was credited by the sources I referenced with raising the level of brain-derived neurotrophic factor (BDNF) in the body.  BDNF not only repairs damaged brain cells, but it also prompts stem cells in the hippocampus to form new neurons.  BDNF is generated during sustained aerobic exercise, and so exercise is the most powerful tool in the Dementia Toolkit.

But, after reading an article in the New England Journal of Medicine, I was prompted to began a 20 hour/day (sort of) fasting protocol in 2020.  Intermittent fasting is not recommended for the elderly, because many of us have trouble maintaining an adequate weight.  But I am currently five pounds over where I want to be, and fasting appears to have been beneficial to me.  So I continue.

For the past year and a half or so, my memory and cognition have been tested weekly by researchers from the University of Washington's Alzheimer's Disease Research Center.  While I don't have access to their protocols for analyzing the data, I have no trouble telling that I'm doing just fine.  I've also found that I score best late in the morning, after some coffee, after the gym, but before eating anything.

So how do fasting, the gut-brain axis, and brain health intersect?  There was recent research from China published in the journal Frontiers in Cellular and Infection Microbiology finding an association between weight loss due to intermittent fasting and brain health.  The researchers correlated intermittent fasting, improvements in the health of gut microbiome (all those little things swimming around inside your gut), and brain health.  Long story short, intermittent fasting is good for the health of the gut microbiome, so the gut microbes do a better job of regulating brain activity.

Here's an article about the study from Newsweek -- a little easier reading than the journal article.  Most people do intermittent fasting for weight loss, so that's the context for the study.  But there are other reasons to fast, so I don't think the association with weight loss in either the Newsweek or journal articles are central to the phenomenon.  If you do all the things to support your gut, it will help your brain.  This Healthline article lists 10 things you can do to support your gut biome.  Notables include eating fiber, eating fermented foods (I eat kimchee and yogurt every day), eating whole grains, etc.

How does the gut-brain axis work?  It's pretty mysterious to me, but this passage from the Wikipedia article is interesting: 

"Chemicals released in the gut by the microbiome can vastly influence the development of the brain, starting from birth.  A review from 2015 states that the microbiome influences the central nervous system by 'regulating brain chemistry and influencing neuro-endocrine systems associated with stress response, anxiety and memory function.' The gut, sometimes referred to as the 'second brain,' may use the same type of neural network as the central nervous system, suggesting why it could have a role in brain function and mental health."  

Your body is truly amazing.

Sushi for Brain Health?

While I grew up on the East Coast, I moved to Hawaii right after school and lived there many years.  My wife was born there and graduated from the University of Hawaii.  (Go Rainbows!).  All of our children were born there.  Like about a third of the population of Hawaii, Amy's ancestry is Japanese, and she and many others share their Japanese cultural artifacts in the Hawaii cultural smorgasbord.  One of these is a love for sushi, although more than a century of separation from its islands of origin have led to a form of sushi quite different from either modern Tokyo or, for that matter, Seattle.  

While I like the sushi I've had in Japan and Seattle, I've never really cared for the sushi people make in Hawaii.  But one thing they all share is wasabi as an ingredient, and I do love that.  I had been told, and always believed, that wasabi was just the Japanese name for horseradish.  And I like to put horseradish on various foods.  But I recently learned that they are not the same thing, although horseradish (a product cheaper to produce) is often portrayed as wasabi.  (Just add green food coloring.)  They do share similar taste and the ability to clean out your nose.

So why are we talking about this?  Some recently published research from Japan found that consumption of an extract from wasabi (something that's apparently not in horseradish) can significantly improve cognition in older adults -- age 60 to 80.  Note that this is among cognitively healthy adults.  No research has been conducted with Alzheimer's patients.

The research was published in the journal Nutrients.  It studied a cohort of 72 subjects, about half of whom were given an extract from wasabi called  6-MSITC.  (The rest received a placebo.)  The study's lead researcher, Rui Nouchi, told reporters, "We knew from earlier animal studies that wasabi conferred health benefits.  But what really surprised us was the dramatic change. The improvement was really substantial."

According to the research, participants who received 100mg of wasabi extract at bed time improved episodic memory scores an average of 18%.  They scored on average 14% higher than the placebo group overall. 

Why should this happen?  The researchers believe that the wasabi reduces oxidation and inflammation in the hippocampus.  What a coincidence.  Those are the main modes of action of the dementia toolkit we describe in Beating the Dementia Monster.

Reading this research prompted my wife and me to immediately start scouring the refrigerator and pantry to see if we had any on hand.  We, of course, were looking for genuine wasabi, and not horseradish disguised as wasabi (dyed green).  The tube of paste we thought we had was gone, but we did find a small unopened can.  It had expired in February 2020.

Here's a news article about this.

Apparently, to be effective, the wasabi needs to be fresh.  In paste form, it's usually refrigerated.  Since I do like wasabi, and the researchers say it doesn't take much to see a result, I went ahead and ordered some on Amazon.  We'll see if anything amazing happens.

Now a more reliable way of evaluating diet and cognitive decline

Nutritionists and other researchers have been trying for years to correlate the Mediterranean diet with its influence on the rate of cognitive decline.  Does adhering to the diet slow cognitive decline, either from normal aging or from disease?  

We discussed this in Beating the Dementia Monster.  Research to date has actually been a bit confused.  Some research finds the diet is great for the brain, while other studies found no help.

What's going on here?  Well, the big challenge is knowing whether people are accurately reporting what they eat.  The studies are all based on surveys, and the study participants must accurately report how they eat.  My observation is that this information is highly subjective and subject to wishful thinking.  Aren't we all good boys and girls that always eat our Brussels sprouts?

And what about pizza?  Isn't that Mediterranean?  To dieticians like the late Dr. Martha Clare Morris, it's the worst possible food for brain health.  But I'd bet that gets reported as Mediterranean in some surveys.

Studies to date have been qualified and held at arms length by many researchers.  So what to do?

Recently, researchers in France published 12 years worth of research that took a novel approach to verifying what people actually consumed.  Basically, they sampled the blood of the participants and analyzed for the metabolites that should be there if someone is adhering to the diet.  They did this in two geographically distinct study populations.

So what's a metabolite?  A metabolites is a molecule from the chemicals that result when food is metabolized, and they can be found in the blood stream.  Spinach will produce one set of metabolites, while a chocolate eclair will produce another set.  Ingenious.

The research was published in October in the journal Molecular Nutrition and Food Research.  The researchers concluded, "A greater adherence to the [Mediterranean diet], here assessed by a serum [Mediterranean diet metabolic score], is associated with lower odds of [cognitive decline] in older adults."  Here's an article about the study.

How much did the diet help with cognitive decline?  Good question.  And they aren't clear about that.  So I'm guessing not as much as you might hope.

You probably know that I try to follow the MIND diet.  MIND stands for “Mediterranean-DASH Intervention for Neurodegenerative Delay.”  It tries to derive the best from both the Mediterranean and DASH diets.  The DASH diet was designed to help with heart health.  And you know what the neurologists all say: "What's good for the heart is good for the brain!"  I'd just say most simply that the MIND diet is the Mediterranean diet without cheese, butter, and stick margarine.  And maybe an extra helping of blueberries.  The MIND diet seems to produce better results than the Mediterranean and DASH diets for brain health,