adipocyte composition

[Wuzzy]

sorry just a correction:

wuzzy wrote:

>., adipocyte aspirates show that SFA in tissue doesn't
>(necessarily!) correlate with saturated fat in the
diet
>again showing it isn't essential.

Actually this means that % SFA is highly affected by amount
of PUFA so change in PUFA will change the %SFA in adipose..
it would be nice to design a study to find out whether carb
has any effect on %sfa in adipose.. should be easy to do
since the datasets have already been developed just not
studied for carb..

[Wuzzy]

Determination of fatty acid and triacylglycerol composition of
human adipose tissue. The fatty acid composition of adipose
tissue was studied in a population with a diet in which the
fat contribution is mainly from olive oil. The lipid
composition of adipose tissue .. major triacylglycerol was
POO, followed by PLO and OOO. J Chromatogr 1992 Oct
23;581(2):171-8

wuzzy notes: POO is dioleopalmitin, PLO is
palmitolinoleo-olein and OOO is trioleiN

to me this was highly insightful: Triglycerides are really
three fatty acids that have been esterified
(alcohol+carboxylic/fatty acid) - eg., Olive oil is really
made up of the triglyceride olein, *NOT* the fatty oleic acids
as commonly thought..

here we see that the major adipose triglycerides are _mixed
triglycerides_.

so we see there is complex esterefication/re-esterification
happening. hepatic sensitive lipase, lipoprotein lipase and
asylation stimulating protein have weird effects that break
down fatty acids and G3P re-esterifies these so you get weird
mixtures..

[Wuzzy]

wuzzy wrote:

>so we see there is complex esterefication/re-esterification
happening.
>hepatic sensitive lipase, lipoprotein lipase and asylation
stimulating
>protein have weird effects that break down fatty acids and
>G3P re-esterifies these so you get weird mixtures..

note how the triglyceride mixtures almost all have saturated
fats in them, so the adipose is usually solid at room
temperature..

so that a person who eats very little saturated fat, but lots
of olive oil, might still have triglycerides with 2 oleic
fatty acids and 1 palmitic acid, which as a triglyceride would
be solid at room temperature..

It is clear that fats in the diet are what is stored and that
carb isn't stored as fat except in the sense that it is
hierarchically used as fuel leaving the olive oil to be
stored.. it would be unusual and unlikely to see saturated fat
(palmitic is the main product of carb converted to fat)
correlate with dietary carb - doesn't happen - mostly dietary
fats correlate with fat aspirates...

[Wuzzy]

>It is clear that fats in the diet are what is stored and that
>carb isn't stored as fat except in the sense that it is
>hierarchically
used
>as fuel leaving the olive oil to be stored..

similarly some fats are not stored and are used for
metabolic purposes, leaving the other fats to be stored or
used as energy..
ie., there is "fuel partitioning happening".. something
similar is described when we talk about "carbs being
anabolic" in terms of muscle, the carbs don't turn to
muscle but they can partition protein into muscle..

[Wuzzy]

I have a copy of a 1960 article that studied adipose
composition, in case ppl are curious it came to:

20%palmitic 40%oleic 14%linoleic

note that these %ages don't reflect diet because they are
used metabolically or structurally nevertheless a 10%
increase in linoleic will correlate with adipose linoleic..
note oleic (mufa) is the main fat that is stored in humans
according to this study.. I suspect this is because it
*isn't* used metabolically and it is much easier to store
than saturated fat.

[Wuzzy]

last post I have a review on epidemiology of adipocyte
composition, note japan (21.3% saturated) was not
statistically significant from 4 other country even though
they have *much* higher carbohydrate. (carb is theoretically
only converted to palmitic/saturated)..

also the fact that mufa is the main human fat shows that
dietary fat is stored in a hierarchy of fuel partitioning, and
carb doesn't appreciably convert to fat..

[Wuzzy]

mypcos@hotmail.com (wuzzy) wrote in message
news:<d996c21a.0210301830.218d2d73@posting.google.com>...
> last post I have a review on epidemiology of adipocyte
> composition, note japan (21.3% saturated) was not
> statistically significant from 4 other country even though
> they have *much* higher carbohydrate. (carb is theoretically
> only converted to palmitic/saturated)..
>
> also the fact that mufa is the main human fat shows that
> dietary fat is stored in a hierarchy of fuel partitioning,
> and carb doesn't appreciably convert to fat..

okay I did find one study that showed that %16:1
(theoretically the carbohydrate fat) was higher in low fat
dieters - I automatically attributed this to de novo
lipogenesis but thought about it and considered it is more
likely due to the low levels of linoleic acid in the diet
causing *percent* 16:1 to go up.. I have emailed the authors
to see if adjusting for dietary
16:1 there is any correlation between adipose 16:1 and dietary
carb. Also, MUFA and SFA tend not to be related to diet
since they are highly internally converted - I didn'
realize there was so much literature on this topic..

[September]

mypcos@hotmail.com (wuzzy) wrote in message
news:<d996c21a.0210301830.218d2d73@posting.google.com>...
> last post I have a review on epidemiology of adipocyte
> composition, note japan (21.3% saturated) was not
> statistically significant from 4 other country even though
> they have *much* higher carbohydrate. (carb is theoretically
> only converted to palmitic/saturated)..
>
> also the fact that mufa is the main human fat shows that
> dietary fat is stored in a hierarchy of fuel partitioning,
> and carb doesn't appreciably convert to fat..

Interesting discussion.

Maybe you have some insight into this question:

Can short-chain saturated fatty acids be stored in adipose
cells? The reason I ask is because of a post I read on an
internet bb...

-"Dr. Mary Enig said in her book the body rarely stores short
chain fatty acids (fat from saturated fat) in fat cells, but
rather long chain fatty acids synthesized from excess blood
sugar converted to triglycerides by insulin. The short fatty
acid chains are being used for body maintenance and energy."-

This seems to be in agreement with what you are saying about a
hierarchy of fuel partitioning in regards to dietary fat
storage. But do you think the body will preferentially store
glucose-derived sat fats over dietary sat fats? And how much
impact, if true, would this have on adipocyte composition
since dietary carb is not appeciably converted to fat?

Any comment would be appreciated :)

[Larry Hoov]

"wuzzy" <mypcos@hotmail.com> wrote in message
news:d996c21a.0210310526.2bf2dd6a@posting.google.com...
> mypcos@hotmail.com (wuzzy) wrote in message
news:<d996c21a.0210301830.218d2d73@posting.google.com>...
> > last post I have a review on epidemiology of adipocyte
> > composition, note japan (21.3% saturated) was not
> > statistically significant from 4 other country even though
> > they have *much* higher carbohydrate. (carb is
> > theoretically only converted to palmitic/saturated)..
> >
> > also the fact that mufa is the main human fat shows that
> > dietary fat is stored in a hierarchy of fuel partitioning,
> > and carb doesn't appreciably convert to fat..
>
> okay I did find one study that showed that %16:1
> (theoretically the carbohydrate fat) was higher in low fat
> dieters - I automatically attributed this to de novo
> lipogenesis but thought about it and considered it is more
> likely due to the low levels of linoleic acid in the diet
> causing *percent* 16:1 to go up.. I have emailed the authors
> to see if adjusting for dietary
> 16:1 there is any correlation between adipose 16:1 and
> dietary carb. Also, MUFA and SFA tend not to be related
> to diet since they are highly internally converted - I
> didn' realize there was so much literature on this
> topic..

If you follow my stream-of-consciousness represented by this
series of links, I think I found your answer.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db-
=PubMed&list_ui ds=10889793&dopt=Abstract

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db-
=PubMed&list_ui ds=10837287&dopt=Abstract

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db-
=PubMed&list_ui ds=11684525&dopt=Abstract

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db-
=PubMed&list_ui ds=11684525&dopt=Abstract

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db-
=PubMed&list_ui ds=10956277&dopt=Abstract

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db-
=PubMed&list_ui ds=7864247&dopt=Abstract

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db-
=PubMed&list_ui ds=10744780&dopt=Abstract

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db-
=PubMed&list_ui ds=11157321&dopt=Abstract

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db-
=PubMed&list_ui ds=8621798&dopt=Abstract

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db-
=PubMed&list_ui ds=9537610&dopt=Abstract

[Wuzzy]

Off topic, average dietary fat is highly related to adipose
fat take a look at
http://www.accessv.com/~joemende/adipose.jpg

also if you look at the USDA under animal fats (say pork etc.)
it is very similar to human adipose - which is odd since many
of these animals eat grains all day then again they are able,
unlike humans to convert large amounts of starch to fat -

comments? just a coincidence?

[Larry Hoov]

"wuzzy" <mypcos@hotmail.com> wrote in message
news:d996c21a.0210311911.646e66fa@posting.google.com...
> Off topic, average dietary fat is highly related to adipose
> fat take a look at
> http://www.accessv.com/~joemende/adipose.jpg
>
> also if you look at the USDA under animal fats (say pork
> etc.) it is very similar to human adipose - which is odd
> since many of these animals eat grains all day then again
> they are able, unlike humans to convert large amounts of
> starch to fat -
>
> comments? just a coincidence?

I suspect it has to do with a conserved genetic trait found in
omnivorous mammals.

Each of these abstracts has a full-text link in Pubmed.

Consider:

J Clin Invest 1996 May 1;97(9):2081-91

Human fatty acid synthesis is stimulated by a eucaloric low
fat, high carbohydrate diet.

Hudgins LC, Hellerstein M, Seidman C, Neese R, Diakun J,
Hirsch J.

Laboratory of Human Behavior and Metabolism, Rockefeller
University, New York, NY 10021, USA.
hudgins@rockvax.rockefeller.educ

A new experimental approach was used to determine whether a
eucaloric, low fat, high carbohydrate diet increases fatty
acid synthesis. Normally volunteers consumed low fat liquid
formula diets (10% of calories as fat and 75% as glucose
polymers, n = 7) or high fat diets (40% of calories as fat
and 45% as glucose polymers, n = 3) for 25 d. The fatty acid
composition of each diet was matched to the composition of
each subject's adipose tissue and compared with the
composition of VLDL triglyceride. By day 10, VLDL
triglyceride was markedly enriched in palmitate and deficient
in linoleate in all subjects on the low fat diet. Newly
synthesized fatty acids accounted for 44 +/- 10% of the VLDL
triglyceride. Mass isotopomer distribution analysis of
palmitate labeled with intravenously infused 13C-acetate
confirmed that increased palmitate synthesis was the likely
cause for the accumulation of triglyceride palmitate and
"dilution" of linoleate. In contrast, there was minimal fatty
acid synthesis on the high diet. Thus, the dietary
substitution of carbohydrate for fat stimulated fatty acid
synthesis and the plasma accumulation of palmitate-enriched,
linoleate-deficient triglyceride. Such changes could have
adverse effects on the cardiovascular system.

Am J Clin Nutr 1998 Apr;67(4):631-9

Human fatty acid synthesis is reduced after the substitution
of dietary starch for sugar.

Hudgins LC, Seidman CE, Diakun J, Hirsch J.

Rockefeller University, New York, NY 10021, USA.
hudgins@rockvax.rockefeller.edu

Using new nonisotopic and isotopic methods, we showed
previously that fatty acid synthesis was markedly stimulated
in weight-stable normal volunteers by a very-low-fat formula
diet with 10% of energy as fat and 75% as short glucose
polymers. In this study, we determined whether fatty acid
synthesis was equally stimulated by a very-low-fat solid diet
made with foods consumed typically. Four normal volunteers
consumed the same very-low-fat formula diet for 25 d and then
an isoenergetic solid food diet with 10% of energy as fat and
75% as starch, simple sugars, and fiber for 25 d. To measure
fatty acid synthesis, the fatty acid compositions of the diets
were matched to the composition of each subject's adipose
tissue and compared with the composition of
VLDL-triacylglycerol. In all subjects, the large increases in
newly formed palmitate and decreases in linoleate in
VLDL-triacylglycerol were quickly reversed by the solid food
diet, and the fraction of de novo synthesized fatty acids in
fasting VLDL-triacylglycerol decreased from 30-54% to 0-1%. In
a second group of subjects, the stimulation of fatty acid
synthesis by the formula diet with 75% glucose polymers was
similarly reduced by a formula diet with amounts of fat,
starch, and sugar chosen to mimic those of the solid food
diet, but persisted after the addition of fiber or a diet with
75% sugar. In conclusion, an increase in fatty acid synthesis
and palmitaterich, linoleate-poor VLDL-triacylglycerol induced
by very-low-fat, high-sugar diets may be reduced by the
substitution of dietary starch for sugar with potentially
beneficial effects on cardiovascular health.

Am J Clin Nutr 2001 Feb;73(2):253-61

Postprandial de novo lipogenesis and metabolic changes
induced by a high-carbohydrate, low-fat meal in lean and
overweight men.

Marques-Lopes I, Ansorena D, Astiasaran I, Forga L,
Martinez JA.

Departments of Physiology and Nutrition and of Food Science,
University of Navarra, Pamplona, Spain.

BACKGROUND: Adjustments of carbohydrate intake and oxidation
occur in both normal-weight and overweight individuals.
Nevertheless, the contribution of carbohydrates to the
accumulation of fat through either reduction of fat oxidation
or stimulation of fat synthesis in obesity remains poorly
investigated. OBJECTIVE: The objective of this study was to
assess the postprandial metabolic changes and the fractional
hepatic de novo lipogenesis (DNL) induced by a
high-carbohydrate, low-fat meal in lean and overweight young
men. DESIGN: A high-carbohydrate, low-fat meal was
administered to 6 lean and 7 overweight men after a 17.5-h
fast. During the fasting and postprandial periods, energy
expenditure (EE), macronutrient oxidation, diet-induced
thermogenesis, and serum insulin, glucose, triacylglycerol,
and fatty acids were measured. To determine DNL, [1-13C]sodium
acetate was infused and the mass isotopomer distribution
analysis method was applied. RESULTS: After intake of the
high-carbohydrate meal, the overweight men had
hyperinsulinemia and higher fatty acid and triacylglycerol
concentrations than did the lean men. The overweight group
showed a greater EE, whereas there was no significant
difference in carbohydrate oxidation between the groups.
Nevertheless, the overweight men had a marginally higher
protein oxidation and a lower lipid oxidation than did the
lean men. DNL was significantly higher before and after meal
intake in the overweight men and was positively associated
with fasting serum glucose and insulin concentrations.
Furthermore, postprandial DNL was positively correlated with
body fat mass, EE, and triacylglycerol. CONCLUSION: After a
high-carbohydrate, low-fat meal, overweight men had a lower
fat oxidation and a higher fractional hepatic fat synthesis
than did lean men.

[Wuzzy]

Thanks Larry, I think de novo lipogenesis is underestimated in
humans for two reasons:
1)most studies assess *hepatic* lipogenesis which is
negliglble compared to adipose. (see ref#1).
2)even slight amounts of fat can downregulate lipogenesis.

In reference 1 they fed 4 subjects corn starch meals via the
nose, 88% carb, 4000KCAL/day and found that 170g fat/d was
synthesized. That is: 2000 extra kcal of carb, or 400grams,
were converted to at least 170g of fat. (40% of excess kcal
converted - indicating low efficiency)

So DNL probably does happen and probably contributes, say, 10%
of fat to adipose stores at most..

Dietary Linoleic acid (vegetable oil) is low in most animal
species including humans so that adipose stores are also low
(~10%) whereas MUFA and SFA is high in the diet and can be
converted (Mufa is just a longer, desaturated version of SFA).

Animals fed with grains will have to produce saturated fats
from these so that their MUFA+SFA adipose fat stays high
whereas their linoleic remains low (or even drops).

[Larry Hoov]

"wuzzy" <mypcos@hotmail.com> wrote in message
news:d996c21a.0211031257.709a39e5@posting.google.com...
> Thanks Larry, I think de novo lipogenesis is underestimated
> in humans for two reasons:
> 1)most studies assess *hepatic* lipogenesis which is
> negliglble compared to adipose. (see ref#1).
> 2)even slight amounts of fat can downregulate lipogenesis.
>
> In reference 1 they fed 4 subjects corn starch meals via the
> nose, 88% carb, 4000KCAL/day and found that 170g fat/d was
> synthesized. That is: 2000 extra kcal of carb, or 400grams,
> were converted to at least 170g of fat. (40% of excess kcal
> converted - indicating low efficiency)

I've always used the conversion factor of 9 kcal/g for fat, so
at least 1530 kcal would have been stored away......conversion
in excess of 75%.

> So DNL probably does happen and probably contributes, say,
> 10% of fat to adipose stores at most..
>
> Dietary Linoleic acid (vegetable oil) is low in most
> animal species including humans so that adipose stores are
> also low (~10%) whereas MUFA and SFA is high in the diet
> and can be converted (Mufa is just a longer, desaturated
> version of SFA).
>
> Animals fed with grains will have to produce saturated fats
> from these so that their MUFA+SFA adipose fat stays high
> whereas their linoleic remains low (or even drops).

So linoleate still retains its utility as an inferential
assessment of calorie sources?

[Wuzzy]

Rough morning on smn..

anyway this thread (adipocyte comp) is good, maybe worth a
review. One remarkable article everyone must read is:"De novo
lipogenesis in humans" EJCN 53:Supp 53-65.

On paragraph 5, he comments how Hirsch(1965) observed that
adipose FA composition is similar to diet. Adipose composition
was mainly studied in the 60s I have several AJCN articles
that did reviews on different population samples (references
are in my shelf of papers available on request).. The article
goes on to demistify DNL in one paragraph he comments how
contribution of carbs to adipose *used* to be a mystery but
isn't anymore, I agree with him entirely..

-wuzzy (no longer mystified by the topic of A.,Comp., when it
comes up like it did two issues ago AJCN)

[Larry Hoov]

"wuzzy" <mypcos@hotmail.com> wrote in message
news:d996c21a.0211080734.5a34064c@posting.google.com...
> Rough morning on smn..
>
> anyway this thread (adipocyte comp) is good, maybe worth a
> review. One remarkable article everyone must read is:"De
> novo lipogenesis in humans" EJCN 53:Supp 53-65.

This one looks like it would be a fascinating read in
full-text:

Diabetes Metab Res Rev 2002 Sep-Oct;18(5):345-56

An adipocentric view of signaling and intracellular
trafficking.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db-
=PubMed&list_ui ds=12397577&dopt=Abstract