Re: linoleic acid vs sat fat -- how about fish oil?

February 6, 2005

Hi JW:

LOL. Since you ask (and after months of my advocating here to eat

fish) I decided I perhaps ought to check the details for fish fat

content. So I checked atlantic herring.

100 grams contains 158 calories and nine grams fat.

What is interesting is that no specific fat predominates. Eight fats

supply half a gram or more. The most is oleic (nothing wrong with

that) at 1.52g; second is palmitic (would prefer to avoid it) 1.35g;

then there are six others each contributing between half a gram and

one gram. In descending order they are: DHA, erucic, gadoleic, EPA,

palmitoleic, and myristic. Yes, about half a gram of myristic.

Looking at this list one might not have guessed it to be so healthy.

It also makes one wonder whether fish oil capsules might be better,

if it REALLY is the DHA and EPA that provide the benefit, and

***IF*** the capsules largely or completely eliminate the myristic,

erucic and palmitic. I bet they don't. Is there a source for pretty

much pure EPA and DHA?

Rodney.

--- In , " jwwright " <jwwright@e...>

wrote:

> With all the discussion about linoleic, makes me wonder what the

(3) eq's tell us about fish PUFA's?

>

> Regards.

>

> -- Original Message -----

> From: citpeks

>

> Sent: Friday, February 04, 2005 11:34 PM

> Subject: [ ] Re: New file uploaded to

>

> I thought that the phrase " They [FAO/WHO] specifically recommend

> consumption of linoleic acid at the 10% level when total intake of

> saturated fatty acids is high " was in accordance with the numbers

that

> we have been calculating with the Hegsted equation: one part of

> safflower oil (or grapeseed or sunflower) counteracts the effect

of

> two parts of lard, as far as cholesterol is concerned.

>

> Here are some more numbers to calculate how to meet LA

requirements:

> A 2000-calorie Zone diet (30% fat) requires 600 calories from

fat. If

> we want to have 10% of the calories from LA, that is 200 calories

or

> 22 grams of LA. Let us say that we want to eat a whole food, like

> sunflower seeds, to satisfy this requirement. What amount of

> sunflower seeds do we need to eat, and how many calories will they

> have? (because besides the LA there will be other fatty acids and

> protein).

>

> Sunflower seeds have ~50% oil of which ~68% is LA. This means

that

> 34% of the weight of sunflower seeds consists of LA. So to get 22

> grams of LA, you need to eat 65 grams of sunflower seeds (about

1/2

> cup). From the Nutrition Facts we know that 33g of seeds have 190

> calories. Therefore, 65g of seeds have 374 total calories of

which

> 292 are from fat, which is slightly less than half of the total

daily

> calories for fat. The 65g of seeds also contain about 16 grams of

> protein.

>

> Depending on your caloric intake, 1/4 to 1/2 cup of sunflower

seeds

> would provide the LA requirement.

>

> Tony

>

> ====

> Message 17422

> From: " Rodney " <perspect1111@y...>

> Date: Fri Feb 4, 2005 5:20 pm

> Subject: Re: New file uploaded to

>

> The safflower oil issue is an interesting one. How much linoleic

is

> sufficient to get the lion's share of the benefits to be had,

before

> diminishing returns (and increasing calories) set in?

>

> I just checked broccoli. 100 grams contains 35 calories and 51 mg

of

> linoleic. Am I right that that is about 1% of what may be

> desirable? Are there better vegetable sources of linoleic that do

> not contain the types of fats we do not need, or want? Avocado has

> more, but it also contains other fats, that we do not need, to go

> with it. Or is a small amount of safflower oil the best bet - the

> most linoleic for the smallest number of calories? Five grams a

day,

> perhaps? Not a huge amount.

>

> " Requirements for EFAs

>

> Linoleic acid: a minimum of 1 to 3+% of calories. Only small

amounts

> of linoleic acid (an n-6 acid) are required. An RDA/RDI has not

been

> formally adopted; however linoleic acid at 1-2% of calories will

> prevent deficiency. NRC [1989] recommends a minimum intake of

> linoleic acid, for adults, of 3-6 g/day. The comments of Jumpsen

and

> Clandinin [1995, p. 29] are appropriate here:

>

> ...ecause competition exists among the fatty acids for

> desaturating enzymes (Brenner, 1981), a level of at least 3% of

> energy should be met by n-6 fatty acids (FAO, 1977)...

> Uauy et al. (1989) recently suggested that the recommendation of

3.0%

> of total energy is adequate to prevent clinical signs of

deficiency

> but may be insufficient to ensure functional and biochemical

normalcy.

>

> FAO [1995], a joint publication with the United Nations World

Health

> Organization (WHO), recommends linoleic acid consumption in the

range

> of 4-10% of total energy. They specifically recommend consumption

of

> linoleic acid at the 10% level when total intake of saturated

fatty

> acids is high. Note that the FAO/WHO-recommended consumption

level is

> higher than the suggested minimums. "

>

> http://www.beyondveg.com/billings-t/comp-anat/comp-anat-7h.shtml

> (probably *not* an unimpeachable source)

>

> Rodney.

February 6, 2005

Fish oil is an interesting case. According the the Hegsted equation,

fish oil can increase your cholesterol twice as much as lard.

However, fish oil contains many long-chain unsaturated fatty acids

that have different metabolic functions. In particular, the C20 fatty

acids, which include EPA, are involved in what is called the

" eicosanoid cascade " which produces many hormone-like substances,

e.g., prostaglandins, prostacyclins, leucotrienes, etc.

The enzyme cyclooxygenase (COX) mediates the metabolism of these

long-chain fatty acids. Many pain relievers, some of which were

recently shown to be dangerous (VIOXX), alter these metabolic

pathways.

The following link gives an overview of the complex metabolism of

fats.

http://web.indstate.edu/thcme/mwking/lipid-synthesis.html

The fact that fats are very important constituents of the human body

(cellular membranes, eicosanoids, etc.) makes it imperative to eat

only natural fats, rather than fats that have been chemically

processed.

Tony

===

From: " jwwright " <jwwright@e...>

Date: Sat Feb 5, 2005 6:36 pm

Subject: linoleic acid vs sat fat -- how about fish oil?

With all the discussion about linoleic, makes me wonder what the (3)

eq's tell us about fish PUFA's?

Regards.

February 6, 2005

Hi All,

Henry Huxley, the 19th-century British scientist, said that

science has many examples of beautiful hypotheses slain by ugly facts.

Using the Hegsted equation, rests on the hypothesis that it is

correct, correct?

Cheers, Al Pater

>

> Fish oil is an interesting case. According the the Hegsted

equation,

> fish oil can increase your cholesterol twice as much as lard.

> However, fish oil contains many long-chain unsaturated fatty acids

> that have different metabolic functions. In particular, the C20

fatty

> acids, which include EPA, are involved in what is called the

> " eicosanoid cascade " which produces many hormone-like substances,

> e.g., prostaglandins, prostacyclins, leucotrienes, etc.

>

> The enzyme cyclooxygenase (COX) mediates the metabolism of these

> long-chain fatty acids. Many pain relievers, some of which were

> recently shown to be dangerous (VIOXX), alter these metabolic

> pathways.

>

> The following link gives an overview of the complex metabolism of

> fats.

> http://web.indstate.edu/thcme/mwking/lipid-synthesis.html

>

> The fact that fats are very important constituents of the human body

> (cellular membranes, eicosanoids, etc.) makes it imperative to eat

> only natural fats, rather than fats that have been chemically

> processed.

>

> Tony

>

> ===

> From: " jwwright " <jwwright@e...>

> Date: Sat Feb 5, 2005 6:36 pm

> Subject: linoleic acid vs sat fat -- how about fish oil?

>

> With all the discussion about linoleic, makes me wonder what the (3)

> eq's tell us about fish PUFA's?

>

> Regards.

February 6, 2005

The quantitative relationships expressed by the Hegsted equation are

not derived from a 'hypothesis', they are the result of mathematical

analysis of many **measurements** of the effect of specific fatty

acids on blood lipid metabolism. The equation has general

applicability because it was developed from data for many individuals.

Since there is variability in the effect of fats on specific

individuals, the resulting equation can only make predictions with a

specific margin of confidence, but it is reliable enough that it is

widely used for dietary analysis.

Quantitative relationships that are developed from measurements, such

as Isaac Newton's gravitational equations are able to withstand the

test of centuries. Apples will continue to fall from the trees with

an acceleration of 9.8 meters/second squared, regardless of any

hypotheses to the contrary. ... and myristic acid will still be over

eight times more cholesteremic than stearic acid even for Huxley's

descendants.

Tony

=====

Am J Clin Nutr. 1965 Nov;17(5):281-95.

Quantitative effects of dietary fat on serum cholesterol in man.

Hegsted DM, McGandy RB, Myers ML, Stare FJ.