5 ms·

Patterns of Regional Cerebral Blood Flow as a Function of Obesity in Adults

85 points by InInteraction 6y ago

jeffreyrogers 6y ago
Presumably this has more to do with body composition/diet than weight, right? I.e. a muscular person with a healthy diet and normal amount of body fat but with high BMI is not at higher risk. (I'm not debating the merits of using BMI, I realize it is a useful proxy).
- acvny 6y ago
  Correct, but this is so rare that can be ignored.
  - Grimm1 6y ago
    Huh what? Any high muscle athletic person would hit this.
    - bjo590 6y ago
      What percentage of males in the US with a BMI over 30 (obese) have a body fat percentage less than 25? My guess is less than 3%, but I don't have data to back it up. When studying populations you can ignore these outliers. It's well known that BMI works well for populations but can fail when looking at individual health.
      - codyswann 6y ago
        Checking in - MBI over 30. Body Fat Percentage less than 10. It's not rare in my circles
        NeutronStar 6y ago
        And your circles account for how much of the population would you guess?
        kossTKR 6y ago
        Really, 10% body fat with 30+ BMI? Without steroids, that sounds completely bonkers to me.. Can you link me a picture of a natural body that looks like yours, i'm pretty intrigued.
        nradov 6y ago
        The point is that individuals with high BMI and low body fat are rare in the general population, and can be ignored as statistical noise in most broad scientific studies. Your circles would only be relevant for studies specifically targeting body builders.
        Grimm1 6y ago
        They're not though, what? I want to see you back up this claim with evidence before passing it off as fact. Edit: It is fairly easy to be < 25% body fat with normal musculature that accompanies normal weight lifting and cardio routines 4 times a week. That will get you to a BMI +30 at 5"10 +
        Nzen 6y ago
        What's the concentration of high-BMI-with-low-body fat in the general population ? Armed with that, I'll choose a p value myself, as to whether it's rare. Anecdotally, I agree, but I can't be sure that I am in contact with a represeentative sample.
      - Grimm1 6y ago
        Care to back it up I dispute that this is in fact rare. Edit:I counter with anyone who lifts and play sports and is 5" 10'+ will hit < 25% body fat and a bmi +30. You only need to be 225 pounds and at 6" 1' to be bmi +30 at 5" 10' that's only 210. I saw that fairly regularly (or at least I did precovid) at the gym.
        bjo590 6y ago
        > I saw that fairly regularly (or at least I did precovid) at the gym. Yeah, I saw (pre-covid) it all the time at the gym, at amateur sports leagues, and at health food stores. It's also worth noting that my zipcode also has a significantly lower obesity rate than the national average. If I were to go to an Alabama Walmart the fit & muscular people people would be much more uncommon. https://www.cdc.gov/obesity/data/prevalence-maps.html https://www.cdc.gov/obesity/data/prevalence-maps.html
    - fortran77 6y ago
      "The Rock" is Height 6′ 5″, Weight 260 lbs That's a BMI of 30.8 which put him on the bottom of the "obese" range. (Obese starts at 30). Obviously he's not obese. But most people who claim that they "BMI Doesn't apply to me" even though their BMI is over 30 don't look like The Rock. And he _just_ hits the obese range! If you're not an elite professional bodybuilder or weightlifter (i.e., you don't look like The Rock) BMI is probably a very good rule-of-thumb.
      - csa 6y ago
        That’s an extreme example — he’s on the very lean side in terms of body fat %. A quick google search has him at ~10% body fat and 6’3” 236 lbs. That means his lean body mass is 212 lbs. So he could gain ~21 lbs and still be squarely in the average range of body fat (20%). Tack on 8-10 lbs more for the high end of average (24%). With the 20% number, his weight would be 257 —- that’s squarely in the BMI obese category for someone who is 6’3”. The BMI numbers are just not useful for folks with a relatively high amount of lean body mass for their height. One does not need to be a body builder or gym rat to meet this criterion. A small amount of body-weight exercises plus cardio is enough for people who build muscle easily (it’s not that rare). As others have said, BMI can be useful for measuring trends in populations, but some people get carried away when using it on individuals.
        fortran77 6y ago
        I don't think the average gym rat would have a BMI in the "obese" range (maybe overweight) unless they start getting into "Rock" territory. That was my point. I'm a "gym rat" (I'm the co-owner of a gym). Lift weights every day. I look athletic. I'm 5'10" 170#. That's a BMI of 24. Not even in the "overweight" range. Most people who say "BMI is meaningless/unfair/outdated" aren't in the group of people who outliers. It is a very good quick check, especially for considering the characteristics of a population when looking for correlations (like obesity vs cognitive ability, or obesity vs Type II diabetes). Doctors tend to record height and weight of patients with reasonable accuracy. Even doing other measurements like hip/waist ratio are a bit subjective (where, exactly is the waist. Where are the hips--especially on an obese subject. How "tight" are you holding the tape measure?) BMI eliminates those subjective elements.
  - csa 6y ago
    For fast twitch people who exercise, it’s not that rare.
- xwdv 6y ago
  A study like this would probably account for that by comparing people of similar activity levels. I assume like with most things athletic individuals would have less risk anyway.
- greenbush 6y ago
  Note that BMI varies by ethnicity. BMI is meant to be a rough measure of body fat, but the muscle & fat ratios vary by ethnicity. "When compared to white Europeans of the same BMI, Asians have 3 to 5 percent higher total body fat. South Asians, in particular, have especially high levels of body fat and are more prone to developing abdominal obesity, which may account for their very high risk of type 2 diabetes and cardiovascular disease. In contrast, some studies have found that blacks have lower body fat and higher lean muscle mass than whites at the same BMI, and therefore, at the same BMI, may be at lower risk of obesity-related diseases." https://www.hsph.harvard.edu/obesity-prevention-source/ethnic-differences-in-bmi-and-disease-risk/ https://www.hsph.harvard.edu/obesity-prevention-source/ethni...
xwdv 6y ago
In layman's terms, the fatter you get the dumber you get. A layman would also look at a country like say, America, where obesity has been on the rise for decades, and the population seems to get increasingly uneducated and insular, and deduce this to be true.
- alextheparrot 6y ago
  The study observed a correlation, please don’t put forward a causative narrative when these could just be correlated or causative in a way different from the way you propose.
  - amanaplanacanal 6y ago
    Yes! After decades of research we still have no idea what is driving the population level increases in obesity. There are a lot of possibilities, but which one is right?
  - xwdv 6y ago
    Given that obesity is the cause of a whole host of ailments, I’d say it’s fine to play it fast and loose and put forward this narrative. Is it scientifically rigorous? No, but sometimes there isn’t enough time for rigor and you’re better of making an educated guess than having no conclusion at all.
waihtis 6y ago
Wonder if this applies the same for both ”muscular” and ”fat”?
- antidaily 6y ago
  Probably don’t have same blood flow issues being muscular as being fat.
  - xdavidliu 6y ago
    can you provide a citation?
asutekku 6y ago
Clickbaity title aside (seriously, that’s the original press release title), pretty damning results. Basically a higher BMI means a higher probability to get an alzheimer’s disease.
seibelj 6y ago
The media has almost entirely ignored how the majority of young people who died of Covid were obese. Two days ago the NYT finally acknowledged this as a risk factor despite it being obvious to anyone paying attention https://www.nytimes.com/2020/08/14/health/covid-19-obesity.html https://www.nytimes.com/2020/08/14/health/covid-19-obesity.h... Being fat is an enormous risk factor for dying of Covid, but instead of a giant “Get Out and Jog” campaign we are just supposed to hunker down inside and pray for a vaccine. Being fat is a sign of generally poor health. It hurts your immune system. It reduces your quality of life. It has ripple effects to the rest of your body. The fat positivity movement is one of the worst movements ever to exist. There is nothing positive about being fat. It is only negative.
- mrfusion 6y ago
  If I was in charge during this I would have done a huge get healthy campaign. Vitamin d for all, free gym memberships and park fees, healthy food campaign. (Plus protecting nursing homes) It would let people feel like they’re doing something to fight the disease. It would bring us positivity instead of negativity, and the health improvements would pay dividends for years. Oh also a massive volunteer effort for healthy people to deliver food and medicine to the elderly and vulnerable.
  - Someone1234 6y ago
    Sounds like if you were in charge you would have done the opposite of social distancing (e.g. free gym/parks, volunteers visiting tons of people's homes, etc). This seems like a strategy that could increase the spread significantly.
    - mrfusion 6y ago
      Interesting point. The volunteers would have to be super careful. I’d envision leaving the food outside the door.
      - narag 6y ago
bryanrasmussen 6y ago
As Alzheimer's and most other neural degenerative diseases progress body weight decreases rapidly. I would also think, based on some people with eating disorders I've observed where the weight decreased, that a very low body weight also might have an alarming impact on brain function - not sure how surprising it would be and if really a cause and not a correlation. Probably just a correlation.
exabrial 6y ago
> FunctionHigher BMI is linked to decreased cerebral blood flow Most people equate weight=high BMI, so the title is probably accurate for a casual audience but it's important to note the study is actually looking at BMI.
- bostonpete 6y ago
  BMI is linearly related to weight, so for a given person, whose height is fixed, it's appropriate to think of this as the impact of weight....
dade_ 6y ago
8% difference from normal to obese seems expected, not alarming. I don’t see anything in the study that factors for exercise though it is the health advice provided in the article. ‘Regular exercise linked to higher blood flow in brain’ seems a more appropriate, not dramatized headline. Thank you Captain Obvious.
wrkronmiller 6y ago
Worth noting that the first author is CEO of this clinic [0]: https://www.amenclinics.com https://www.amenclinics.com > At Amen Clinics, it all starts with you. We look at your biological, psychological, social and spiritual influences to get a complete picture of who you are as a person. With life coaching, nutritional guidance and personalized therapy, we provide the tools you need to feel confident, complete and hopeful for the future. We are dedicated to helping you find the answer to you. 0: https://www.j-alz.com/manuscript-disclosures/20-0655r2 https://www.j-alz.com/manuscript-disclosures/20-0655r2
alextheparrot 6y ago
From reading the proof, it seems the authors are mainly focused on “linking” or showing correlation, not causation. Part of me wonders about the directionality of causation here (If we assumed one existed). One could argue the hippocampus, which from my recollection is involved in inhibiting impulsive behavior, has a clear path to being a causative agent for obesity. Distinguishing between the two narratives of “Being overweight inhibits brain function” versus “Differences in part of brain controlling impulses leads to weight differences” is important to resolving it, as it is easier to imagine treatment regimens to combat weight more than brain blood flow. It is also completely possible these two variables do not affect each other, but are correlated. That’s useful still, because it means we may be able to use body weight increases as an inferred marker for the brain changes. It would be incredibly interesting if the story of Alzheimer’s transformed more into “Same factor may be causing both America’s obesity increases as well as Alzheimer’s cases” Edit: Updated this a few times while reading the original paper
- CyberDildonics 6y ago
  Or maybe fructose intake and absorption correlates to both obesity and cognitive function.
  - alextheparrot 6y ago
    I fell into the same over-reaching trap I was critiquing, which is a bit funny, but I agree they could be caused by the same thing and correlated because of that as well.
- bawana 6y ago
  Absolutely. The whole constellation of diminished brain function and obesity brings to mind a hibernation switch that is getting turned on. Perhaps further research will elucidate the biochemical pathway that is active in these patients and allow us to put people into ‘suspended animation’ for long space voyages. “ You have to eat 2 lbs of spaghetti and a gallon of ice cream a day for a month before going to mars in your sleep couch”
ta17711771 6y ago
Oxygenation is important.
mrfusion 6y ago
It’s interesting that high blood pressure is linked to poor brain health outcomes (AFAIK). Maybe high blood pressure is the body trying to compensate for reduced blood flow?
- treeman79 6y ago
  IHH. High inter cranial pressure is horrible on cognitive abilities. If I get a spike, it can take a week to be back to normal brain function. It puts a lot of pressure on the veins, taking them close to bursting. Body needs time to heal. One insidious part is that exercise makes it worse. So if you exercise, pressure spikes, you need a week or two to recover. I spent years trying to push through exhaustion, but everytime I worked out I would need weeks to recover. So I made little progress. Proper diagnosis and medication suddenly enabled me to exercise daily. Massive life changer.
  - nradov 6y ago
    For most people, exercise reduces blood pressure (post exercise hypotension).
mrfusion 6y ago
I wish studies like these would look at apoe4 status.
sjmj3us 6y ago
I'm suspecious of this because the author is Dr Daniel Amen. Who makes a lot of money from brain scans that are considered suspect by many medical professionals. I would be inclined to withhold judgement until some more objective group corroborates this.
- alextheparrot 6y ago
  The word “impact” here is incredibly misleading, as most people would infer a causal relationship from that word, when the study and subtext are all about correlation. I don’t think the science (As in the raw data and charts) is necessarily bad, but the title of the linked article (Which is not the title of the original article) is needlessly imprecise (Or precise in the wrong ways, I suppose).
- kevin_thibedeau 6y ago
  Anybody with infomercials on PBS should be regarded with suspicion.
fortran77 6y ago
There are many published, referenced papers on this: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5651104/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5651104/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4737453/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4737453/ etc. However, this is a topic that we are not allowed to discuss here.
gpm 6y ago
Worth noting that the vast majority of the participants in this study had existing mental disorders, 57% "generalized anxiety", 51% ADHD, 17% Major Depression, 7.4% Bipolar Disorder, and so on. The authors claim (but don't show their work) that adjusting for these factors did not change the statistical significance of the relationship, but it does still mean this isn't exactly a representative sample of the population. Very interesting that underweight people generally have more blood flow than "normal" weight people, though if you dive into the supplementary data that doesn't hold for every region of the brain studied (and the general trend seems to hold in all regions studied).
sparrish 6y ago
I have a hard time believing this study. Anecdotally - I have about 10 years experience in assisted living homes (read early stages for dementia and Alzheimer's) and I can't think of a single dementia resident that wasn't thin as a rail. I also can't recall a single overweight resident that had dementia. Grain of salt and all that.

85 points by InInteraction 6y ago

Presumably this has more to do with body composition/diet than weight, right? I.e. a muscular person with a healthy diet and normal amount of body fat but with high BMI is not at higher risk. (I'm not debating the merits of using BMI, I realize it is a useful proxy).

acvny 6y ago
Correct, but this is so rare that can be ignored.
- Grimm1 6y ago
  Huh what? Any high muscle athletic person would hit this.
  - bjo590 6y ago
    What percentage of males in the US with a BMI over 30 (obese) have a body fat percentage less than 25? My guess is less than 3%, but I don't have data to back it up. When studying populations you can ignore these outliers. It's well known that BMI works well for populations but can fail when looking at individual health.
    - codyswann 6y ago
      Checking in - MBI over 30. Body Fat Percentage less than 10. It's not rare in my circles
      - NeutronStar 6y ago
        And your circles account for how much of the population would you guess?
      - kossTKR 6y ago
        Really, 10% body fat with 30+ BMI? Without steroids, that sounds completely bonkers to me.. Can you link me a picture of a natural body that looks like yours, i'm pretty intrigued.
      - nradov 6y ago
        The point is that individuals with high BMI and low body fat are rare in the general population, and can be ignored as statistical noise in most broad scientific studies. Your circles would only be relevant for studies specifically targeting body builders.
        Grimm1 6y ago
        They're not though, what? I want to see you back up this claim with evidence before passing it off as fact. Edit: It is fairly easy to be < 25% body fat with normal musculature that accompanies normal weight lifting and cardio routines 4 times a week. That will get you to a BMI +30 at 5"10 +
        Nzen 6y ago
        What's the concentration of high-BMI-with-low-body fat in the general population ? Armed with that, I'll choose a p value myself, as to whether it's rare. Anecdotally, I agree, but I can't be sure that I am in contact with a represeentative sample.
    - Grimm1 6y ago
      Care to back it up I dispute that this is in fact rare. Edit:I counter with anyone who lifts and play sports and is 5" 10'+ will hit < 25% body fat and a bmi +30. You only need to be 225 pounds and at 6" 1' to be bmi +30 at 5" 10' that's only 210. I saw that fairly regularly (or at least I did precovid) at the gym.
      - bjo590 6y ago
        > I saw that fairly regularly (or at least I did precovid) at the gym. Yeah, I saw (pre-covid) it all the time at the gym, at amateur sports leagues, and at health food stores. It's also worth noting that my zipcode also has a significantly lower obesity rate than the national average. If I were to go to an Alabama Walmart the fit & muscular people people would be much more uncommon. https://www.cdc.gov/obesity/data/prevalence-maps.html https://www.cdc.gov/obesity/data/prevalence-maps.html
  - fortran77 6y ago
    "The Rock" is Height 6′ 5″, Weight 260 lbs That's a BMI of 30.8 which put him on the bottom of the "obese" range. (Obese starts at 30). Obviously he's not obese. But most people who claim that they "BMI Doesn't apply to me" even though their BMI is over 30 don't look like The Rock. And he _just_ hits the obese range! If you're not an elite professional bodybuilder or weightlifter (i.e., you don't look like The Rock) BMI is probably a very good rule-of-thumb.
    - csa 6y ago
      That’s an extreme example — he’s on the very lean side in terms of body fat %. A quick google search has him at ~10% body fat and 6’3” 236 lbs. That means his lean body mass is 212 lbs. So he could gain ~21 lbs and still be squarely in the average range of body fat (20%). Tack on 8-10 lbs more for the high end of average (24%). With the 20% number, his weight would be 257 —- that’s squarely in the BMI obese category for someone who is 6’3”. The BMI numbers are just not useful for folks with a relatively high amount of lean body mass for their height. One does not need to be a body builder or gym rat to meet this criterion. A small amount of body-weight exercises plus cardio is enough for people who build muscle easily (it’s not that rare). As others have said, BMI can be useful for measuring trends in populations, but some people get carried away when using it on individuals.
      - fortran77 6y ago
        I don't think the average gym rat would have a BMI in the "obese" range (maybe overweight) unless they start getting into "Rock" territory. That was my point. I'm a "gym rat" (I'm the co-owner of a gym). Lift weights every day. I look athletic. I'm 5'10" 170#. That's a BMI of 24. Not even in the "overweight" range. Most people who say "BMI is meaningless/unfair/outdated" aren't in the group of people who outliers. It is a very good quick check, especially for considering the characteristics of a population when looking for correlations (like obesity vs cognitive ability, or obesity vs Type II diabetes). Doctors tend to record height and weight of patients with reasonable accuracy. Even doing other measurements like hip/waist ratio are a bit subjective (where, exactly is the waist. Where are the hips--especially on an obese subject. How "tight" are you holding the tape measure?) BMI eliminates those subjective elements.
- csa 6y ago
  For fast twitch people who exercise, it’s not that rare.
xwdv 6y ago
A study like this would probably account for that by comparing people of similar activity levels. I assume like with most things athletic individuals would have less risk anyway.
greenbush 6y ago
Note that BMI varies by ethnicity. BMI is meant to be a rough measure of body fat, but the muscle & fat ratios vary by ethnicity. "When compared to white Europeans of the same BMI, Asians have 3 to 5 percent higher total body fat. South Asians, in particular, have especially high levels of body fat and are more prone to developing abdominal obesity, which may account for their very high risk of type 2 diabetes and cardiovascular disease. In contrast, some studies have found that blacks have lower body fat and higher lean muscle mass than whites at the same BMI, and therefore, at the same BMI, may be at lower risk of obesity-related diseases." https://www.hsph.harvard.edu/obesity-prevention-source/ethnic-differences-in-bmi-and-disease-risk/ https://www.hsph.harvard.edu/obesity-prevention-source/ethni...

xwdv 6y ago

In layman's terms, the fatter you get the dumber you get. A layman would also look at a country like say, America, where obesity has been on the rise for decades, and the population seems to get increasingly uneducated and insular, and deduce this to be true.

alextheparrot 6y ago
The study observed a correlation, please don’t put forward a causative narrative when these could just be correlated or causative in a way different from the way you propose.
- amanaplanacanal 6y ago
  Yes! After decades of research we still have no idea what is driving the population level increases in obesity. There are a lot of possibilities, but which one is right?
- xwdv 6y ago
  Given that obesity is the cause of a whole host of ailments, I’d say it’s fine to play it fast and loose and put forward this narrative. Is it scientifically rigorous? No, but sometimes there isn’t enough time for rigor and you’re better of making an educated guess than having no conclusion at all.

waihtis 6y ago

Wonder if this applies the same for both ”muscular” and ”fat”?

antidaily 6y ago
Probably don’t have same blood flow issues being muscular as being fat.
- xdavidliu 6y ago
  can you provide a citation?

asutekku 6y ago

Clickbaity title aside (seriously, that’s the original press release title), pretty damning results. Basically a higher BMI means a higher probability to get an alzheimer’s disease.

seibelj 6y ago

The media has almost entirely ignored how the majority of young people who died of Covid were obese. Two days ago the NYT finally acknowledged this as a risk factor despite it being obvious to anyone paying attention https://www.nytimes.com/2020/08/14/health/covid-19-obesity.html https://www.nytimes.com/2020/08/14/health/covid-19-obesity.h... Being fat is an enormous risk factor for dying of Covid, but instead of a giant “Get Out and Jog” campaign we are just supposed to hunker down inside and pray for a vaccine. Being fat is a sign of generally poor health. It hurts your immune system. It reduces your quality of life. It has ripple effects to the rest of your body. The fat positivity movement is one of the worst movements ever to exist. There is nothing positive about being fat. It is only negative.

mrfusion 6y ago
If I was in charge during this I would have done a huge get healthy campaign. Vitamin d for all, free gym memberships and park fees, healthy food campaign. (Plus protecting nursing homes) It would let people feel like they’re doing something to fight the disease. It would bring us positivity instead of negativity, and the health improvements would pay dividends for years. Oh also a massive volunteer effort for healthy people to deliver food and medicine to the elderly and vulnerable.
- Someone1234 6y ago
  Sounds like if you were in charge you would have done the opposite of social distancing (e.g. free gym/parks, volunteers visiting tons of people's homes, etc). This seems like a strategy that could increase the spread significantly.
  - mrfusion 6y ago
    Interesting point. The volunteers would have to be super careful. I’d envision leaving the food outside the door.
    - narag 6y ago

bryanrasmussen 6y ago

As Alzheimer's and most other neural degenerative diseases progress body weight decreases rapidly. I would also think, based on some people with eating disorders I've observed where the weight decreased, that a very low body weight also might have an alarming impact on brain function - not sure how surprising it would be and if really a cause and not a correlation. Probably just a correlation.

exabrial 6y ago

> FunctionHigher BMI is linked to decreased cerebral blood flow Most people equate weight=high BMI, so the title is probably accurate for a casual audience but it's important to note the study is actually looking at BMI.

bostonpete 6y ago
BMI is linearly related to weight, so for a given person, whose height is fixed, it's appropriate to think of this as the impact of weight....

dade_ 6y ago

8% difference from normal to obese seems expected, not alarming. I don’t see anything in the study that factors for exercise though it is the health advice provided in the article. ‘Regular exercise linked to higher blood flow in brain’ seems a more appropriate, not dramatized headline. Thank you Captain Obvious.

wrkronmiller 6y ago

Worth noting that the first author is CEO of this clinic [0]: https://www.amenclinics.com https://www.amenclinics.com > At Amen Clinics, it all starts with you. We look at your biological, psychological, social and spiritual influences to get a complete picture of who you are as a person. With life coaching, nutritional guidance and personalized therapy, we provide the tools you need to feel confident, complete and hopeful for the future. We are dedicated to helping you find the answer to you. 0: https://www.j-alz.com/manuscript-disclosures/20-0655r2 https://www.j-alz.com/manuscript-disclosures/20-0655r2

alextheparrot 6y ago

From reading the proof, it seems the authors are mainly focused on “linking” or showing correlation, not causation. Part of me wonders about the directionality of causation here (If we assumed one existed). One could argue the hippocampus, which from my recollection is involved in inhibiting impulsive behavior, has a clear path to being a causative agent for obesity. Distinguishing between the two narratives of “Being overweight inhibits brain function” versus “Differences in part of brain controlling impulses leads to weight differences” is important to resolving it, as it is easier to imagine treatment regimens to combat weight more than brain blood flow. It is also completely possible these two variables do not affect each other, but are correlated. That’s useful still, because it means we may be able to use body weight increases as an inferred marker for the brain changes. It would be incredibly interesting if the story of Alzheimer’s transformed more into “Same factor may be causing both America’s obesity increases as well as Alzheimer’s cases” Edit: Updated this a few times while reading the original paper

CyberDildonics 6y ago
Or maybe fructose intake and absorption correlates to both obesity and cognitive function.
- alextheparrot 6y ago
  I fell into the same over-reaching trap I was critiquing, which is a bit funny, but I agree they could be caused by the same thing and correlated because of that as well.
bawana 6y ago
Absolutely. The whole constellation of diminished brain function and obesity brings to mind a hibernation switch that is getting turned on. Perhaps further research will elucidate the biochemical pathway that is active in these patients and allow us to put people into ‘suspended animation’ for long space voyages. “ You have to eat 2 lbs of spaghetti and a gallon of ice cream a day for a month before going to mars in your sleep couch”

ta17711771 6y ago

Oxygenation is important.

mrfusion 6y ago

It’s interesting that high blood pressure is linked to poor brain health outcomes (AFAIK). Maybe high blood pressure is the body trying to compensate for reduced blood flow?

treeman79 6y ago
IHH. High inter cranial pressure is horrible on cognitive abilities. If I get a spike, it can take a week to be back to normal brain function. It puts a lot of pressure on the veins, taking them close to bursting. Body needs time to heal. One insidious part is that exercise makes it worse. So if you exercise, pressure spikes, you need a week or two to recover. I spent years trying to push through exhaustion, but everytime I worked out I would need weeks to recover. So I made little progress. Proper diagnosis and medication suddenly enabled me to exercise daily. Massive life changer.
- nradov 6y ago
  For most people, exercise reduces blood pressure (post exercise hypotension).

mrfusion 6y ago

I wish studies like these would look at apoe4 status.

sjmj3us 6y ago

I'm suspecious of this because the author is Dr Daniel Amen. Who makes a lot of money from brain scans that are considered suspect by many medical professionals. I would be inclined to withhold judgement until some more objective group corroborates this.

alextheparrot 6y ago
The word “impact” here is incredibly misleading, as most people would infer a causal relationship from that word, when the study and subtext are all about correlation. I don’t think the science (As in the raw data and charts) is necessarily bad, but the title of the linked article (Which is not the title of the original article) is needlessly imprecise (Or precise in the wrong ways, I suppose).
kevin_thibedeau 6y ago
Anybody with infomercials on PBS should be regarded with suspicion.

fortran77 6y ago

There are many published, referenced papers on this: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5651104/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5651104/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4737453/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4737453/ etc. However, this is a topic that we are not allowed to discuss here.

gpm 6y ago

Worth noting that the vast majority of the participants in this study had existing mental disorders, 57% "generalized anxiety", 51% ADHD, 17% Major Depression, 7.4% Bipolar Disorder, and so on. The authors claim (but don't show their work) that adjusting for these factors did not change the statistical significance of the relationship, but it does still mean this isn't exactly a representative sample of the population. Very interesting that underweight people generally have more blood flow than "normal" weight people, though if you dive into the supplementary data that doesn't hold for every region of the brain studied (and the general trend seems to hold in all regions studied).

sparrish 6y ago

I have a hard time believing this study. Anecdotally - I have about 10 years experience in assisted living homes (read early stages for dementia and Alzheimer's) and I can't think of a single dementia resident that wasn't thin as a rail. I also can't recall a single overweight resident that had dementia. Grain of salt and all that.