Glutamine Reduces Fat Stores

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jay - 21 Jun 2010 23:06 GMT

What would have been the likely source of glutamine for humans in the
past? Is it basically plant foods (ie cabbage). Or is it meat?
Glutamine seems to tell the body not to store energy but instead to
burn it? Anybody know if other proteins do the same?

L-glutamine supplementation induces insulin resistance in adipose
tissue and improves insulin signalling in liver and muscle of rats
with diet-induced obesity.

AIMS/HYPOTHESIS: Diet-induced obesity (DIO) is associated with insulin
resistance in liver and muscle, but not in adipose tissue. Mice with
fat-specific disruption of the gene encoding the insulin receptor are
protected against DIO and glucose intolerance. In cell culture,
glutamine induces insulin resistance in adipocytes, but has no effect
in muscle cells. We investigated whether supplementation of a high-fat
diet with glutamine induces insulin resistance in adipose tissue in
the rat, improving insulin sensitivity in the whole animal. MATERIALS
AND METHODS: Male Wistar rats received standard rodent chow or a high-
fat diet (HF) or an HF supplemented with alanine or glutamine (HFGln)
for 2 months. Light microscopy and morphometry, oxygen consumption,
hyperinsulinaemic-euglycaemic clamp and immunoprecipitation/
immunoblotting were performed. RESULTS: HFGln rats showed reductions
in adipose mass and adipocyte size, a decrease in the activity of the
insulin-induced IRS-phosphatidylinositol 3-kinase (PI3-K)-protein
kinase B-forkhead transcription factor box 01 pathway in adipose
tissue, and an increase in adiponectin levels. These results were
associated with increases in insulin-stimulated glucose uptake in
skeletal muscle and insulin-induced suppression of hepatic glucose
output, and were accompanied by an increase in the activity of the
insulin-induced IRS-PI3-K-Akt pathway in these tissues. In parallel,
there were decreases in TNFalpha and IL-6 levels and reductions in c-
jun N-terminal kinase (JNK), IkappaB kinase subunit beta (IKKbeta) and
mammalian target of rapamycin (mTOR) activity in the liver, muscle and
adipose tissue. There was also an increase in oxygen consumption and a
decrease in the respiratory exchange rate in HFGln rats. CONCLUSIONS/
INTERPRETATION: Glutamine supplementation induces insulin resistance
in adipose tissue, and this is accompanied by an increase in the
activity of the hexosamine pathway. It also reduces adipose mass,
consequently attenuating insulin resistance and activation of JNK and
IKKbeta, while improving insulin signalling in liver and muscle. PMID:
17604977

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Doug Freyburger - 22 Jun 2010 19:46 GMT

> What would have been the likely source of glutamine for humans in the
> past? Is it basically plant foods (ie cabbage). Or is it meat?
> Glutamine seems to tell the body not to store energy but instead to
> burn it? Anybody know if other proteins do the same?

"Natural flavors" on labels are often glutamates. The term is used
because mono-sodium-glutamate MSG is well known and disliked but
glutamates improve flavor so other forms of glutamate are used.

It is speculated that the "fifth taste" unami is achieved by detecting
glutamates so thus in a sense it is the taste of protein. This chain of
reasoning is pretty weak but so far it's the best explanation of unami
that I have read. I think better explanations will come along in time.

The word unami comes from Japanese and the Japanese use foods high in
glutamates to increase unami in their foods to make them taste better.
That works parallel to why folks had pepper to foods to increase the
taste or salt to foods to increase the taste. The Japanese use
condiments made from soy for the glutamates, especially fermented soy
products. There are also some seaweed species used to increase unami.

> L-glutamine supplementation induces insulin resistance in adipose
> tissue and improves insulin signalling in liver and muscle of rats
> with diet-induced obesity.

That sounds good as opposed to the "seems to tell the body not to store
energy but instead to burn it" above.

> AIMS/HYPOTHESIS: Diet-induced obesity (DIO) is associated with insulin
> resistance in liver and muscle, but not in adipose tissue. Mice with
[quoted text clipped - 22 lines]
> adipose tissue. There was also an increase in oxygen consumption and a
> decrease in the respiratory exchange rate in HFGln rats.

When low carb plans started there was stress on total amount of carbs,
then glycemic load, then fiber, and now on types of carb from studies
that fructose triggers more fat storage gram for gram than glucose.

Then low carb plans started paying attention to types of fat. Problems
with transfats, ratios of the essential fatty acids, issues favoring
monosaturates, dealing with media complaints about saturates when they
are actually beneficial to low carbers. More recent optimizations have
been about using coconut oil and other variations.

> CONCLUSIONS/
> INTERPRETATION: Glutamine supplementation induces insulin resistance
[quoted text clipped - 3 lines]
> IKKbeta, while improving insulin signalling in liver and muscle. PMID:
> 17604977

It is natural and good that discussion about protein grams evolved into
discussions about ratios of amino acids. Now it's about details of
specific types of amino acids. Such details give depth and breadth to
the field.

Trying to reduce the results of this study to a sound bite, I will most
likely reduce it farther than reason allows. May as well start out with
a first try and see how it goes -

In spite of the claims that non-fermented soy products are bad because
of the effects of plant hormones, fermented soy products are good
because of the benficial effect of the extra glutamates. Other high
glutamate foods like the cruciferous family are also good, not that a
study that says to eat more cabbage family is a surprise to any low
carber. Sprinkle Maggi Sauce on brocolli or Tamari on cauliflower.

Jay, I take it that my summary is probably wrong. Do you have better
ways to apply the study into practical advice?

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Kaz Kylheku - 01 Jul 2010 00:10 GMT

>> What would have been the likely source of glutamine for humans in the
>> past? Is it basically plant foods (ie cabbage). Or is it meat?
[quoted text clipped - 4 lines]
> because mono-sodium-glutamate MSG is well known and disliked but
> glutamates improve flavor so other forms of glutamate are used.

Glutamate isn't glutamine. They are similar, but
with a key difference:

Glutamic acid (one of whose sodium salts is monosodium glutamate):

O O
|| ||
HO-C-C-C-C-C-OH
|
NH2

Glutamine is:

O O
|| ||
H2N-C-C-C-C-C-OH
|
NH2

The difference is the NH2 group on the end in place of the OH.

Though glutamine can be formed from glutamic acid, and this happens in your
body, MSG-loaded foods are not a way to get your L-glutamine.

> The word unami comes from Japanese and the Japanese use foods high in
> glutamates to increase unami in their foods to make them taste better.

That would be "umami".

Unami is a Japanese surname.

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