The quest for Optimum Nutrition

[Guest guest]

WOW! These posts on polyunsaturated fats are pointing out that

Optimum Nutrition is a very elusive concept. You can minimize CVD at

the expense of getting cancer, or is it the other way around? Each of

us seems to have a different concept of how much protein, fat, and

carbs our diet should have. Some prefer vegetarian diets, others

omnivorous diets. There does not seem to be much overall agreement.

We are convinced that caloric restricton works to extend life (at

least in mice), but there is no " human chow " that would make it simple

to just eat less and have a human CRON program.

Yes, we can do CR, but we are very far from knowing what ON is.

Tony

[Guest guest]

Tony: (and all): As I posted a couple of days ago, I just made a new file

called " How to Buy Oil " . Perhaps that is not the final word. Or perhaps we

need a caveat in that file. We need to come to some sort of consensus about

this. Or perhaps the file was premature???

on 2/20/2005 9:51 PM, citpeks at citpeks@... wrote:

>

> WOW! These posts on polyunsaturated fats are pointing out that

> Optimum Nutrition is a very elusive concept. You can minimize CVD at

> the expense of getting cancer, or is it the other way around? Each of

> us seems to have a different concept of how much protein, fat, and

> carbs our diet should have. Some prefer vegetarian diets, others

> omnivorous diets. There does not seem to be much overall agreement.

>

> We are convinced that caloric restricton works to extend life (at

> least in mice), but there is no " human chow " that would make it simple

> to just eat less and have a human CRON program.

>

> Yes, we can do CR, but we are very far from knowing what ON is.

>

> Tony

>

[Guest guest]

Right!

My take is heart related stuff is more prevalent than cancer and we don't know what causes cancer. Then I have to weigh the advantage of say using a specific diet to lose weight, or lower BP, or lower cholesterol (also elusive), or treat coronary plaque. Other requirements may be to lower metabolism, or raise "fitness" level.

So the palmitate/acetyl CoA cycle ( http://www.whfreeman.com/stryerbiochem5/con_index.htm?22 ) is only one fatty acid process. There must be others, right?

Then there's 18:2 and 18:3 the only identified "essential" fats, but I recall one ref that states we make 18:2 and 18:3 by elongation of 16:2 and 16:3. The 16's are found in green veggies.

And butter has 4:0, 6:0; 8:0; 10:0; 12:0; 14:0 as well as 16:0. So we probably make those.

I think the one site addressed the FA metabolism in the energy process, moving the glucose from a gly state to a FA state. Not necessarily the use of other FA's to produce energy. Does the body have to convert 18's to 16's to burn?

So I think the science of fatty acid metabolism is not complete.

EG: search Pubmed books for fatty acid metabolism:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Search & db=books & doptcmdl=GenBookHL & term=fatty+acid+metabolism+AND+hstat%5Bbook%5D+AND+254319%5Buid%5D & rid=hstat1.section.117820

"More research from various laboratories on potential mechanisms for the effects of omega-3 fatty acids on arrhythmia is needed.

While most studies reported results compared to a control, it might be more relevant to use an omega-6 fatty acid or a monounsaturated fatty acid as the comparison group. Additionally, only three studies evaluated the effect of one omega-3 fatty acid compared to another omega-3 fatty acid. This area needs further research."

Check out:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Search & db=books & doptcmdl=GenBookHL & term=fatty+acid+metabolism+AND+hstat%5Bbook%5D+AND+386163%5Buid%5D & rid=hstat1a.section.22649#22652

"Fatty Acid MetabolismMammalian cells can introduce double bonds into all positions on the fatty acid chain except the n-3 and n-6 position. Thus, the short-chain alpha-linolenic acid (ALA, chemical abbreviation: 18:3n-3) and linoleic acid (LA, chemical abbreviation: 18:2n-6) are essential fatty acids. No other fatty acids found in food are considered ‘essential' for humans, because they can all be synthesized from the short chain fatty acids.

Following ingestion, ALA and LA can be converted in the liver to the long chain, more-unsaturated n-3 and n-6 LCPUFAs by a complex set of synthetic pathways that share several enzymes (Figure 1). LC PUFAs retain the original sites of desaturation (including n-3 or n-6).

The omega-6 fatty acid LA is converted to gamma-linolenic acid (GLA, 18:3n-6), an omega-6 fatty acid that is a positional isomer of ALA. GLA, in turn, can be converted to the longer-chain omega-6 fatty acid, arachidonic acid (AA, 20:4n-6). AA is the precursor for certain classes of an important family of hormone-like substances called the eicosanoids (see below).

The omega-3 fatty acid ALA (18:3n-3) can be converted to the long-chain omega-3 fatty acid, eicosapentaenoic acid (EPA; 20:5n-3). EPA can be elongated to docosapentaenoic acid (DPA 22:5n-3), which is further desaturated to docosahexaenoic acid (DHA; 22:6n-3). EPA and DHA are also precursors of several classes of eicosanoids and are known to play several other critical roles, some of which are discussed further below.

The conversion from parent fatty acids into the LC PUFAs - EPA, DHA, and AA - appears to occur slowly in humans. In addition, the regulation of conversion is not well understood, although it is known that ALA and LA compete for entry into the metabolic pathways."

So verification in a text book that EPA can be made. Hegsted not found in pubmed books.

So keep doing safflower oil to test weight loss idea on adipose tissue.

Regards.

----- Original Message -----

From: citpeks

Sent: Sunday, February 20, 2005 8:51 PM

Subject: [ ] The quest for Optimum Nutrition

WOW! These posts on polyunsaturated fats are pointing out thatOptimum Nutrition is a very elusive concept. You can minimize CVD atthe expense of getting cancer, or is it the other way around? Each ofus seems to have a different concept of how much protein, fat, andcarbs our diet should have. Some prefer vegetarian diets, othersomnivorous diets. There does not seem to be much overall agreement. We are convinced that caloric restricton works to extend life (atleast in mice), but there is no "human chow" that would make it simpleto just eat less and have a human CRON program. Yes, we can do CR, but we are very far from knowing what ON is. Tony

[Guest guest]

Francesca,

My note on how to buy oil was accurate in terms of allowing buyers to

identify oils high in linoleic acid. The criteria in my note will

prevent people from making mistakes when trying to select an oil high

in LA. As you know, just because it is safflower oil, it does not

mean that it is high in LA.

However, whether linoleic acid, or the Hegsted equation, can provide

any benefit to our diets is a question that will probably be debated

for many years depending on our personal philosophies.

In my opinion, there is a large body of scientific literature, not

only Hegsted, that supports the concept that some saturated fats

increase cholesterol and that some polyunsaturated fats decrease

cholesterol. There is also a large body of evidence demonstrating

that high cholesterol levels are associated with cardiovascular

disease, and that excessive body weight (BMI) is associated with CVD,

insulin resistance, and diabetes.

This information convinced me several years ago that I should get my

BMI into the normal range and that I should decrease my cholesterol

level. I have approached this through diet and exercise. I

eliminated hydrogenated fats from my diet, and I now eat 1 teaspoon of

grape seed oil per day. My cholesterol level has gone from 223 to

164. Having conducted this experiment on myself, I feel fairly

certain that the mainstream science on fat metabolism, and the

quantification provided by the Hegsted equation, are squarely on

target.

I also feel that people who have high cholesterol and disregard the

huge volume of evidence on fat metabolism accumulated during the past

40 years do so at their own peril. Unfortunately, the average doctor

is not a chemist or metabolism expert. Doctors are more likely to

prescribe Lipitor, than the elimination of trans fats and addition of

grape seed oil to reduce cholesterol because pharmaceutical companies

" educate " doctors only about the benefits of their products.

With regard to cancer, I don't think that there has been enough

research to decide whether polyunsaturated fats cause cancer, but the

papers I posted earlier do not subtantiate this hypothesis. We will

continue this debate as we find more publications pro and con.

Tony

===

From: Francesca Skelton <fskelton@e...>

Date: Mon Feb 21, 2005 9:27 am

Subject: Re: [ ] The quest for Optimum Nutrition

Tony: (and all): As I posted a couple of days ago, I just made a new

file called " How to Buy Oil " . Perhaps that is not the final word. Or

perhaps we need a caveat in that file. We need to come to some sort of

consensus about this. Or perhaps the file was premature???

[Guest guest]

Understood Tony. I too am interested in keeping my lipid numbers low.

However for those in the group with a high family risk of cancer, I thought

maybe we should qualify the file in some way. ON is indeed a very young

science.

In my case, I have both heart and cancer in the family. In fact, most

people probably do.

on 2/21/2005 12:17 PM, citpeks at citpeks@... wrote:

>

> Francesca,

>

> My note on how to buy oil was accurate in terms of allowing buyers to

> identify oils high in linoleic acid. The criteria in my note will

> prevent people from making mistakes when trying to select an oil high

> in LA. As you know, just because it is safflower oil, it does not

> mean that it is high in LA.

>

> However, whether linoleic acid, or the Hegsted equation, can provide

> any benefit to our diets is a question that will probably be debated

> for many years depending on our personal philosophies.

>

> In my opinion, there is a large body of scientific literature, not

> only Hegsted, that supports the concept that some saturated fats

> increase cholesterol and that some polyunsaturated fats decrease

> cholesterol. There is also a large body of evidence demonstrating

> that high cholesterol levels are associated with cardiovascular

> disease, and that excessive body weight (BMI) is associated with CVD,

> insulin resistance, and diabetes.

>

> This information convinced me several years ago that I should get my

> BMI into the normal range and that I should decrease my cholesterol

> level. I have approached this through diet and exercise. I

> eliminated hydrogenated fats from my diet, and I now eat 1 teaspoon of

> grape seed oil per day. My cholesterol level has gone from 223 to

> 164. Having conducted this experiment on myself, I feel fairly

> certain that the mainstream science on fat metabolism, and the

> quantification provided by the Hegsted equation, are squarely on

> target.

>

> I also feel that people who have high cholesterol and disregard the

> huge volume of evidence on fat metabolism accumulated during the past

> 40 years do so at their own peril. Unfortunately, the average doctor

> is not a chemist or metabolism expert. Doctors are more likely to

> prescribe Lipitor, than the elimination of trans fats and addition of

> grape seed oil to reduce cholesterol because pharmaceutical companies

> " educate " doctors only about the benefits of their products.

>

> With regard to cancer, I don't think that there has been enough

> research to decide whether polyunsaturated fats cause cancer, but the

> papers I posted earlier do not subtantiate this hypothesis. We will

> continue this debate as we find more publications pro and con.

>

> Tony

> ===