[ExI] Old Nutrition Studies

[William Flynn Wallace]

Harvey Newstrom

Much appreciated.  bill w

On Sun, Aug 23, 2015 at 10:44 AM, Harvey Newstrom <mail at harveynewstrom.com>
wrote:

> The China study is old.  It started in 1983 and measured variables of diet
> known at the time.  We know a lot more now.  Nobody should be taking their
> advice from such an old study.  The question of whether this study was
> "right" or "wrong" is irrelevant.  We know a lot more nuance about
> nutrition now than we did then.  So arguing whether this study was right or
> wrong misses the point about whether we should eat meat, fat, cholesterol,
> or turn vegetarian.
>
> Here are some examples of what has changed since the China study and other
> similar older studies.
>
> 1. Early statistics seemed to show that meat causes cancer.  People who
> ate meat get cancer at statistically higher rates than people who didn't
> eat meat.  So it made sense to avoid meat.
>
> However, correlation does not mean causation.  Later studies subdivided
> variables to try to isolate how and why meat causes cancer.  It turns out
> that cooking method was one of the big factors in this.  Charring meat with
> heat creates carcinogens.  If we cook meat without charring it, we avoid
> the creation of most of these carcinogens.
>
> Does that mean the original studies were wrong and meat did not cause
> cancer?  I say no.  As a whole, most meat really was causing cancer.  But
> does this mean that the study was right and should we stop eating meat to
> avoid cancer?  Again, no.  We now know how to cook meat to avoid these
> charring induced carcinogens.  Does that mean reality changed or the
> studies keep flip-flopping?  No, we learn more and more and keep further
> refining our nutritional understanding.  This is not the same as being
> wrong or changing our theories all the time.  We are actually continually
> improving our theories so that they get better and better over time.
>
> 2.  Early statistics seemed to show that cholesterol clogs arteries
> leading to heart attacks.  People who had higher blood cholesterol levels
> get clogged arteries and have heart attacks at statistically higher rates
> than people who don't.  So it made sense to avoid dietary cholesterol.
>
> However, correlation does not mean causation.  Later studies subdivided
> variables even further.  It turns out that dietary cholesterol is very
> small and does not raise blood cholesterol as much as other dietary factors
> that raise cholesterol.  Eating cholesterol containing foods such as eggs
> and shellfish turns out to not raise blood cholesterol very much.  However,
> eating lots of saturated fats and refined carbohydrates turns out to
> skyrocket cholesterol and related compounds like triglycerides.
>
> We also know that there are different kinds of cholesterol, HDL (good)
> cholesterol and LDL (bad) cholesterol and other kinds of cholesterol.  Most
> people have the bad kind, so most early studies found the bad results.  But
> some people who measured "high cholesterol" actually had low bad
> cholesterol and high good cholesterol.  Such people actually had better
> results they higher their good cholesterol got.  So any old study (such as
> the China study) that simply measures "cholesterol" without distinguishing
> the good from the bad is practically useless.  We don't know what they were
> measuring.  We don't know if differences were in the good or bad kind.  We
> don't correlate which changes caused which results.
>
> Does that mean the original studies were wrong and cholesterol did not
> cause heart attacks?  I say no.  As a whole, most high cholesterol readings
> were the bad cholesterol which really was causing heart attacks.  But does
> this mean that the study was right and should we stop eating cholesterol or
> use blood cholesterol levels to predict heart attacks?  Again, no.  We now
> know that total cholesterol does not indicate good or bad predictions.  We
> now look at different cholesterol levels and the ratios between them for
> better measures.  Again, we are not changing the theories about
> cholesterol.  We are further refining our nutritional understanding of how
> different cholesterols effect the cardiovascular system.
>
> 3. There are similar examples with eating a high fat diet.  We now know
> that there are good fats and bad fats.  Early studies did not distinguish
> between good fats and bad fats.  We now know that some fats should be
> decreased in the diet while others should be increased.  It is too
> simplistic to argue whether "fat" is good or bad.
>
> 4. A related example of refining our knowledge occurred with butter vs.
> margarine.  Scientists were correct when they statistically correlated
> saturated fat with heart attacks.  They suggested that people switch from
> butter to vegetable oils.  So many people did.  And many people started
> having more problems than before.  Were the scientists wrong?  Not really.
> We now know that most vegetable oil margarines are hydrogenated, making
> them even more super-saturated than the saturated fats.  They also induced
> more trans fats, which is also a very bad dietary fat.  So while scientists
> recommended that people switch to vegetable oils to eat less saturated far,
> people actually switched to hydrogenated vegetable oils which were even
> more saturated fat than before.  While it was mistakenly believed that
> people were eating less saturated fat, they were actually eating much more
> saturated fat.  We now know a lot more about the whole spectrum of fats.
> And we know that hydrogenated oil!
>  s in margarines are worse than saturated fats in the same way that
> saturated fats are worse than natural vegetable oils.
>
> 5. There are older studies that found that the autopsied brains of people
> who ate soy had more dementia indications than people who did not eat soy.
> However it was later found that the people who ate soy were living longer.
> So what they really found was that older people have more dementia
> indications than younger people.  When correlated for age, people who eat
> soy do not have more dementia indications than people who do not eat soy.
>
> 6. There was a recent theory that too much estrogen might cause hormone
> problems for males and that soy contains a pseudo-estrogen.  So people
> stopped drinking soy milk and switched back to cow's milk.  Then it was
> realized that cow's milk has a magnitude more times real estrogen than soy
> has pseudo estrogens.  If people really wanted to avoid estrogen, they
> should stop drinking cow's milk and switch to soy milk.
>
> My point with these various examples is that science works over time and
> keeps getting better and better.  But it's not perfect.  We cannot argue
> whether an older study is right or wrong.  The answer is almost always more
> nuanced and has to be subdivided into other better questions about what was
> right and what was wrong.  Ideas about increasing or decreasing a single
> food group (meat, grains, dairy) or a single macronutrient (fat, protein,
> carbs) are usually too simplistic.  The more we study these questions, the
> more they fragment into many more precise questions until the original
> question becomes meaningless.
>
> Are carbs good or bad?  Is fat good or bad?  Is meat good or bad?  Is
> vegetarianism better or worse?  Is veganism better or worse?  All of these
> are invalid questions.  Depending what kinds of carbs, fats, meats,
> vegetarian diet or vegan diet you choose, you can answer these questions
> either way.
>
> And the answer to the question about whether any particular study is good
> or bad should be approach by looking at further refined studies.  It almost
> never can be answered by deciding if the study is good (and accepting all
> of its conclusions) or deciding that a study is bad (and rejecting all of
> its conclusions).  Both of these extreme edge-case positions is almost
> always wrong.
>
> --
> Harvey Newstrom   www.HarveyNewstrom.com
>
>
>
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