Re: PUFA (was fats & cholesterol)

[Guest guest]

> It doesn't sound to me like you should need any supplemental oil with

> PUFA. Eggs are rich in PUFA, butterfat has enough PUFA to meet the

> requirement all by itself at 40% of calories, so at a lower amount

> still supplies a substantial contribution, and you have small amounts

> of PUFA in the other foods that add up. However, if you have signs of

> deficiency that resolve with an added oil, I can't really argue with

> that. But in the absence of any kind of dermatitis or dry skin that

> does so, I would not personally bother.

Here are a few studies which indicate that n-3 supplementation may indeed be

helpful for

heart disease and many other problems:

- N-3 deficiencies have been associated with asthma, heart disease and learning

deficiencies (Okuyama H, et al. Prog Lipid Res. 1997;35:4:409-457)

- Epidemiological and population studies indicate that increased consumption of

fish as a

source of omega-3 fatty acids is often associated with decreased mortality (as

well as

morbidity) from cardiovascular disease. (Schmidt EB, Skou HA, Christensen JH,

Dyerberg J.

n-3 Fatty acids from fish and coronary artery disease: implications for public

health. Public

Health Nutr 2000;3(1):91-8.)

- Controlled-intervention trials in humans have indicated a favorable modifying

effect of

dietary fish oils on various risk factors for cardiovascular disease independent

of their

lowering of blood cholesterol. (Angerer P, von Schacky C. n-3 Polyunsaturated

fatty acids

and the cardiovascular system. Curr Opin Lipidol 2000;11(1):57-63.; Connor WE.

The

importance of n-3 fatty acids in health and disease. Am J Clin Nutr 2000;71(1

Suppl):171S-5S.; Holub BJ. Fish oils and cardiovascular disease. CMAJ

1989;141:1063.)

- These effects include an antithrombotic effect, lipid (triglyceride) lowering,

reduced

blood and plasma viscosity, and improvements in endothelial dysfunction.

(Goodfellow J,

Bellamy MF, Ramsey MW, CJH, MJ. Dietary supplementation with marine

omega-3 fatty acids improve systemic large artery endothelial function in

subjects with

hypercholesterolemia. J Am Coll Cardiol 2000;35(2):265-70.)

- Dietary supplementation with encapsulated omega-3 fish oil concentrates has

shown

the potential to reduce both the progression of cardiovascular disease and

related

mortality, including sudden cardiac death. (GISSI-Prevenzione Investigators.

Dietary

supplementation with n-3 polyunsaturated fatty acids and vitamin E after

myocardial

infarction: results of the GISSI-Prevenzione trial. Lancet 1999;354:447-55.;

Raper NR,

Cronin FJ, Exler J. Fatty acid content in the US food supply. J Am Coll Nutr

1992;11:304-8.)

- Vitamin E (-tocopherol) supplementation, which was also studied in the above

trial, was

without significant effect in this regard. These findings support the concept

that,

independent of blood cholesterol lowering, EPA and DHA intakes (including

supplementation) can favorably influence mortality related to cardiovascular

disease

(particularly sudden cardiac death) via various mechanisms including

antiarrhythmic

effects.

- Various studies have also indicated that long-term consumption of fish (up to

2-3

servings per week) appears to be associated with lower primary and secondary

heart

attack rates and death from cardiovascular disease. (Burr ML, Fehily AM, Gilbert

JF,

S, Holliday RM, Sweetnam PM, et al. Effects of changes in fat, fish, and fibre

intakes on

death and myocardial reinfarction: Diet And Reinfarction Trial (DART). Lancet

1989;2:757-

61.; Daviglus ML, S, Orencia AJ, Dyer AR, Liu K, Greenland P, et al.

Fish

consumption and the 30-year risk of fatal myocardial infarction. N Engl J Med

1997;336:1046-53.)

- Among the Inuit of Nunavik, progressive increases in levels of EPA and DHA in

plasma

phospholipid have been found both to reflect dietary intakes of these fatty

acids and to be

beneficially associated with key risk factors for cardiovascular disease.

(Dewailly E,

Blanchet C, Lemieux S, Sauve L, Gingras S, Ayotte P, et al. n-3 Fatty acids and

cardiovascular disease risk factors among the Inuit of Nunavik. Am J Clin Nutr

2001;74:464-73.)

- Human studies have revealed the potent ability of EPA and DHA to significantly

reduce

circulating levels of blood triglyceride, which is of interest because only

moderate

elevations in triglyceride have been associated with a progressively increased

risk of

ischemic heart disease. ( WS. Fish oils and plasma lipid and lipoprotein

metabolism

in humans: a critical review. J Lipid Res 1989;30:785-807.; Jeppesen J, Hein HO,

Suadicani

P, Gyntelberg F. Triglyceride concentration and ischemic heart disease: an

eight-year

follow-up in the Copenhagen Male Study. Circulation 1998;97:1029-36.)

- Within 2-3 weeks of EPA and DHA supplementation, significantly reduced blood

triglyceride levels with an approximate reduction of 6%-8% (or more) per gram of

EPA and

DHA consumed are routinely observed. In a placebo-controlled, double-blind

trial,22 a

26% lowering in fasting triglyceride levels in postmenopausal women receiving 4

g

omega-3 (EPA and DHA) daily over 28 days was recently demonstrated. (Stark KD,

Park EJ,

Maines VA, Holub BJ. Effect of a fish-oil concentrate on serum lipids in

postmenopausal

women receiving and not receiving hormone replacement therapy in a

placebo-controlled,

double-blind trial. Am J Clin Nutr 2000;72:389-94.)

- Supplementation with omega-3 (EPA and DHA), as given in addition to statin

therapy in

patients with combined hyperlipidemia,was found to reduce levels of atherogenic

lipoproteins while more effectively reducing the hemostatic risk profile.

(Nordoy A, Bonna

KH, Sandset PM, Hansen JB, Nilsen H. Effect of omega-3 fatty acids and

simvastatin on

hemastatic risk factors and postprandial hyperlipemia in patients with combined

hyperlipemia. Arterioscler Thromb Vasc Biol 2000;20(1):259-65.)

- Because it appears that lower heart rate variability may be used to predict an

increased

risk of coronary heart disease, mortality and arrhythmic events, evidence that 4

g/day of

EPA and DHA (ABOUT 1.5% OF DAILY ENERGY INTAKE) may increase heart rate

variability in

survivors of myocardial infarction is of interest. (Dekker JM, Crow RS, Folsom

AR, Hannan

PJ, Liao D, Swenne CA, et al. Low heart rate variability in a 2-minute rhythm

strip predicts

risk of coronary heart disease and mortality from several causes: the ARIC

Study.

Circulation 2000;102(11):1239-44.; Christensen JH, Gustenhoff P, Korup E, Aaroe

J, Toft E,

Moller T, et al. Effect of fish oil on heart rate variability in survivors of

myocardial

infarction: a double blind randomised controlled trial. BMJ

1996;312(7032):677-8.)

- Heart rate variability, a noninvasive marker of autonomic nervous system

function, is

reduced with sympathetic predominance and other factors (including reduced

baroflex

sensitivity) that may be favourably modified by omega-3 fatty acids. Dietary

supplementation with fish oil enriched with EPA and DHA (up to 3-4 g

omega-3/day) has

also been reported to enhance systemic large-artery endothelial function as

measured in

male subjects with hyperlipidemia by ultrasonic vessel wall tracking.

(Goodfellow J,

Bellamy MF, Ramsey MW, CJH, MJ. Dietary supplementation with marine

omega-3 fatty acids improve systemic large artery endothelial function in

subjects with

hypercholesterolemia. J Am Coll Cardiol 2000;35(2):265-70.)

- A European study of the effect of dietary omega-3 fatty acids on coronary

atherosclerosis (measured via coronary angiography) in patients with

cardiovascular

disease using a randomized, double-blind, placebo-controlled trial has been

reported.

This study revealed that patients with coronary artery disease given omega-3

(EPA and

DHA) therapy (at levels of about 1.5 g/day) over 2 years had moderately less

progression

and more regression of coronary artery disease (discernible, modest mitigation

of

atherosclerosis) than did patients on placebo. (von Schacky C, Angerer P, Kothny

W,

Theisen K, Mudra H. The effect of dietary omega-3 fatty acids on coronary

atherosclerosis:

a randomized, double-blind, placebo-controlled trial. Ann Intern Med

1999;130:554-62.)

-

While I understand the danger of oxidization, and the mechanism you propose, I'm

not

quite ready to throw out the bulk of evidence supporting the health benefits of

n-3 fatty

acids without more evidence to the contrary (and I don't think anyone else

should either,

but that's just my opinion). I'd much appreciate any peer-reviewed data that

supports the

hypothesis that n-3 supplementation at levels near 1.5% of total calories is

harmful.

K.