From: Brian Atkins (brian@posthuman.com)
Date: Thu May 01 2003 - 19:17:01 MDT
Harvey Newstrom wrote:
> Fair enough!
>
Thanks
I cut out the top part of your reply, but I would like to point out that
right at the beginning of the Lipid Hypothesis section, it makes clear
that the hypothesis is regarding a specific kind of fat- saturated fat.
You seem in some of your comments below to not understand this/complain
that they aren't providing evidence regarding separate kinds of fats.
Clearly the author of the paper did not set out to attack total fat
consumption, but rather certain kinds of fats and the converse idea that
saturated fat is to blame for many diseases.
>
> The discussion of Pritikin doesn't really give any facts or evidence against
> it. Pritikin was originally just low fat, and then later added vegetable
> oils, so it contained unsaturated fats but not saturated fats. There is no
> explanation why this diet was bad.
Actually there is a reference (#1) that claims various health issues
caused by the very low fat diet.
> The paper implies that the addition of
> vegetable oils proved the low fat diet wrong, but instead it merely
> clarified that saturated fats are bad and unsaturated fats are good. No
This is clearly your own viewpoint, correct? I think the point being
made is simply that he was forced to add some kind of fat. We can agree
on that I think, and that is all the author of this paper is attempting
to show at this point in the paper. The fact that the Dr. (who already
had made one poor decision on behalf of his patients- the idea of the
extremely low fat diet) deciding to make the added fats unsaturated ones
does not prove that saturated fats are bad. It may be just another bad
decision he made based on his dogma.
>
> The section on "evidence" gives a history of the rise of heart disease, but
> doesn't really given any evidence of what causes it. It claims that butter
> consumption reduced during this time, but doesn't really address the
> question whether fat consumption when up or down. It assumes total fat
> consumption went down in the American diet proportional with butter
> consumption, and that the modern American diet is less fatty than 60 years
> previous. This is both unproven and unlikely. This is not very strong
> evidence for the decline of fat in the diet, nor is there any evidence of a
I don't see the assumptions you refer to... and clearly to me it is not
even attempting to lump all fats together or show overall fat
consumption went up or down. What it seems to plainly state is that over
that period of time, animal/saturated fat declined as a percentage of
dietary intake, while vegetable oils and sugar etc. increased. Do you
really dispute this? I think there is clear historical evidence.
> cause and effect in any case. Furthermore, most of the studies being
> "refuted" in this article are from the 1950's.
This is because of the central role a lot of this research had on the
formation of the lipid hypothesis. Once the hypothesis formed and gained
traction, 99% of the research after that seems to be directed at
attempting to prove it, and any results that don't match up get either
put under the rug or sometimes blatantly mis-characterized.
It is hard to provide direct evidence to prove an anti-hypothesis (i.e.
that cholesterol/saturated fat does not cause heart disease) when no one
has even really done many studies to get data for that. What you are
left with is what you see here... attempting to go back to supposedly
pro-hypothesis work and show flaws.
>
> The representation of the Framingham Heart Study does not match what I find
> on the Framingham Heart Study webpage
> <http://www.nhlbi.nih.gov/about/framingham/>. The study did not divide
> people into high-fat and low-fat groups, it had a single large group of
> people. It did not focus primarily on diet or fat, but measured all
> different factors in a person's life. High fat versus low fat is not
> mentioned in the list of study findings at
> <http://www.nhlbi.nih.gov/about/framingham/timeline.htm>. Cigarette
> smoking, serum cholesterol, physical activity, blood pressure, menopause,
> psychosocial factors, enlarged ventricles, and other factors are reported,
> but I don't see anything about diet. This was not primarily a diet study,
> nor did it compare high-fat with low-fat groups. I don't see how this
> relates to the "lipid hypothesis", how it was supposedly refuted in this
> article, and what difference it would make if it were.
Harvey the quote provided in the article is directly from the director
of the study himself in 1992. I don't think it is disputable unless it
is somehow out of context.
On their research milestones page, they claim "Major report issued on
relationship of diet and heart disease". Clearly they have studied it.
As to how it relates to the hypothesis, the study clearly claims to be
designed to find the causes of CVD. Many people use it as "evidence":
"Started over a half century ago, the Framingham Heart Study has
provided much of what science knows today about the risks associated
with heart disease. Today, the survey also uses high-tech imaging
procedures such as MRI to obtain a non-invasive look at the heart and
blood vessels. In the segment "How's Your Heart?", you saw how this
technique can uncover the buildup of deadly plaque within the aorta. One
of the primary causes of heart disease is a high-fat diet. How well do
you eat? Do your meals follow the guidelines for healthy diets suggested
by the American Heart Association? There's one way to find out."
http://www.pbs.org/saf/1104/teaching/teaching3.htm
Clearly the _interpretations_ of the results of this study are very
important to shaping many beliefs.
>
> I can't really evaluate most of the studies cited, because it doesn't give
> any details about them or their methodology. However, all the studies are
> ones that were supposed to prove the low-fat hypothesis and failed to do so.
> There were no studies that actually showed that saturated fats were
> required. This seems scant evidence that all studies showing unsaturated
> fat to be superior to saturated fats were all flawed. It also provides
> absolutely no evidence that saturated fats are required in the diet.
The goal in this section of the paper is to attack the hypothesis. There
are no studies regarding potentially positive effects of saturated fats,
because as I pointed out above there really is very little scientific
work that has been done in this area since the "sat fats bad" meme took
off in the 50s and beyond.
>
> The dates of these studies also bothers me. They were 1983, 1983, 1982,
> 1983, 1984, 1985. We no a lot more about fats today than we did 20 years
> ago. These studies may have been flawed since they reduced all fats and
> didn't distinguish between different types. But a lack of proof from
According to reference #5, that study specified between sat fats and
unsaturated oils.
Ref #7 says that a low sat fat was used... the effects of sat fat were
not even tested.
> studies 20 years ago does not refute modern studies performed today. I
> think modern studies clearly do show some fats to be better or at least
> different than other fats. A lack of proof of this fact from 20 years ago
> is not conclusive or convincing
Again keep in mind the purpose of this article. It is attempting to
attack the hypothesis, and it is using the "pillars of support" that
supposedly are the superstrong scientific evidence proving the
hypothesis. What this article is _not_ doing is attempting to thoroughly
debunk all known anti-sat-fat studies. If you have some superstrong
evidence then post it.
>
> The studies that refute the lipid hypothesis were similarly old and flawed.
> They measured "cholesterol" without distinguishing between good (HDL)
> cholesterol and bad (LDL) cholesterol. Cholesterol is not a direct
> predictor of heart attack anyway. Even if these studies are flawed, this
> doesn't address the question of saturated fats in the diet. All of these
> studies discussed by this article seem to be a little off base. None of
> them directly study saturated fat versus unsaturated fat. These studies
> also "failed" to prove cholesterol caused heart attacks, or that dietary
> cholesterol causes serum cholesterol. But these don't directly address the
> question of whether dietary saturated fats are required or not.
First off remember that cholesterol and its purported effects are part
of the hypothesis being attacked. So it must also take some hits. But I
will point out:
ref #11 says that a single change between eating butter and margarine
made a big difference in CVD risk- study from 1991.
ref #12 points out that sat fats and cholesterol are essential for
children/growing brains. And ref #13 from 1994 links lowfat diets for
children with "failure to thrive".
ref #14 points out in a study of Jews living in different environments
that one of the major differences was between animal fats and vegetable
oils.
then multiple studies and facts pointing out many examples of people who
eat very high saturated fat diets and yet have no heart disease (or at
least nothing like how much people on Western diets have). This also I
believe is a good attack on the hypothesis... if sat fat causes health
problems, these people should all have many problems!
>
> Although none of the studies seemed to distinguish between different types
> of fats,
While I do not have the studies to look at, clearly some of them as I
mention above are focusing on different kinds of fats.
>
> The problems with too much polyunsaturated oils seem like they would apply
> to any oil. Excessive consumption of these fats causes obesity-related
Go back up and read in the section about short-chain FAs.. ref #27 from
1998 points out that these are apparently less likely to make you gain
weight. Of course all of these are saturated fats.
> symptoms such as cancer, heart disease, immune system depression, liver
> damage, etc. It also discusses how oils can become oxidized and oxidized
> oils are bad for you. However, it does not show that other oils don't have
> the exact same problems. The paper then discusses the imbalance of too much
> omega-6 and too little omega-3, but fails to show how saturated fats would
> help this balance.
ref #30 purports to say polunsaturated fats should only be 4% of
calories. I don't know what this is based on though.. apparently paleo
diet theory?
ref #32 purports to say polyunsatured fat intake was the one linked to
heart disease and cancer.
In the previous section discussing the types of fats, it is stated that
saturated fats are more chemically stable and less likely to become
oxidized when heated or over time. Do you disagree?
Clearly by dramatically reducing use of vegetable oils high in O-6, we
can significantly help reduce the extreme overabundance of O-6 in
Western diets.
>
> The section that actually gets into the benefits of saturated fats is very
> short compared to the other rambling rants that don't get to the point.
> This section seems to only describe the benefits of saturated fatty acids in
> the body. Most of these uses inside the body provide no clue as to whether
> saturated fat needs to be incorporated in the diet, or if the body is
> incapable of manufacturing its own saturated fat. The second point does
> assert that 50% of dietary fat should be saturated, but it is unclear why.
> They study cited is about the effects of vitamin E on bone health, and not
> details about why this dietary need is given. Besides this minor
> references, all of the points are about the need for saturated fat in the
> tissues, which is not disputed. Even vegetarian animals such as cows
> produce a lot of saturated fat. This paper certainly provides no evidence
> that humans have lost the ability to produce their own saturated fat like
> other animals such that it needs to be incorporated into the diet.
It does also claim that O-3 is better retained when diet is rich in
saturated fats (#42). Also, the title of the #41 study sounds like it is
talking about dietary sat fat, but it's hard to tell.
Although the paper does mention one specific case of clear changes in
human cells (incorporating polyunsaturated fats into cell walls and then
causing cholesterol to be incorporated as a reinforcing agent) when fed
too much polyunsaturated fat, the main point again of the paper is not
so much to argue that saturated fats are perfect, but rather that what
we have replaced them with in our diets is causing us many problems.
>
> The section on cholesterol is similar. It shows all the vital roles
> cholesterol plays internally. it does not show that cholesterol is a
> required nutrient which cannot be created by our bodies.
You must have missed ref #49.
>
> In summary:
> 1. This paper refutes a "low-fat" diet without distinguishing between good
> and bad fats.
I disagree. Clearly the paper attempts to point out problems with things
like polyunsaturated vegetable oils. In fact it identifies them along
with hydrogentated fats as a likely cause of heart disease and cancer.
> 2. This paper uses mostly very old references and few modern sources.
The anti-saturated fat dogma is also based on similar.
> 3. This paper shows a few studies that failed to prove high fat was bad, and
> acted like this was evidence for the reverse.
I would say it showed more than a few, and several were very high
profile studies. It also provided specific examples of dangers of
low-fat diets. What I got out of this paper was not so much that I am
convinced I should eat a lot of saturated fat, but that at least the
case against it and cholesterol does not seem very solid.
And I DO think it is relevant to keep in mind who has funded many of
these anti-animal foods studies, and who also has spent quite a lot of
money lobbying various government organizations.
> 4. This paper showed no studies that high fat was good.
I think there were a few things in there, but yes I wish there were more
studies performed on this subject, especially high saturated fat. It
seems severely underfunded compared to the massive amounts of effort
pointed at trying to find problems with it.
> 5. This paper showed saturated fats were required internally, and then just
> assumed that they must be required in the diet if they are found in the
> body.
You're right it did a poor job at this. It did present plenty of
anecdotal and other evidence though that many of the fats we have
replaced it with are not doing us any good, and also that in some cases
the body uses them in not necessarily good ways rather than reforming
them into saturated fats. And it mentioned in passing that saturated
fats in the diet may help our immune system in various ways.
> 7. This paper showed bad effects of too much or oxidized unsaturated fats,
> but failed to show that saturated fats did not suffer from these same
> negative effects.
It clearly stated they are less likely to become oxidized.
> 8. The paper showed no evidence of good effects from eating saturated fats,
> and no comparison studies that measured saturated fat in the diet at all
> 9. The section on benefits of saturated fat only addressed fatty acids.
> 10. The paper frequently got off on unrelated tangents, like proving dietary
> cholesterol might not cause cholesterol, or meat contains more B-vitamins
> than vegetables, all of which are orthogonal to the discussion of saturated
> fats.
The paper is pushing animal fats and animal-derived fats since these
were the major sources of saturated fats that were originally attacked
back in the 50s or whenever.
> 11. The paper cited a decline in butter use and assumed that this indicated
> a decline in total fat intake.
Not by my reading.
> 12. The paper had a lot of logical fallacies. It combined dissimilar
> categories of items and used evidence about one to apply to another. It had
> sections labeled with one topic which then proceeded to discuss a different
> point. It took a lack of evidence of one theory to indicate support for
> another. It made unsupported assertions laced with references supporting
> minor unrelated points.
>
> There was little to refute in this paper. Most of its logic was flawed and
> its evidence orthogonal to what it was presenting. It mostly boiled down to
> the argument that its theory hasn't been proven wrong and therefore must be
> right. I saw only a few minor implied statements that eating saturated fat
> would be good.
>
> At best, this paper might be a hold-over from an earlier period when all
> fats were lumped together and all cholesterol was thought to be bad. This
> paper does a poor job of asserting the correct position that not all fats
> are bad and not all cholesterol is bad. It does not address diet as much as
> internal chemistry. It also appears to me that the chemistry section
> discussing different types of fats was tacked on to an earlier paper that
> didn't make this distinction. Although all the right definitions were
> included in one section, these distinctions were ignored in the discussion,
> evidence and persuasive sections. By mixing good fats with bad fats, and
> good cholesterol with bad cholesterol, this paper neither supports nor
> refutes the question of whether "fats" are "good" or "bad".
>
I will give you some of that. To me, it simply is an interesting puff
piece regarding some potentially health-increasing hypotheses. It has
enough points to get me to consider the idea that the saturated fat
dogma may be incorrect, but it certainly doesn't prove anything for certain.
-- Brian Atkins Singularity Institute for Artificial Intelligence http://www.singinst.org/
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