PREVENZIONE PRIMARIA (PRE-INFARTO)

ABSTRACTS TRATTI DA     

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Am J Clin Nutr. 2003 Apr;77(4):819-25.

OBJECTIVE: The objective was to examine the association between dietary linolenic acid and the presence of atherosclerotic plaques and the intima-media thickness of the carotid arteries. DESIGN: In a cross-sectional design, we studied 1575 white participants of the National Heart, Lung, and Blood Institute Family Heart Study who were free of coronary artery disease, stroke, hypertension, and diabetes mellitus. High-resolution ultrasound was used to assess intima-media thickness and the presence of carotid plaques beginning 1 cm below to 1 cm above the carotid bulb. We used logistic regression and a generalized linear model for the analyses.

RESULTS: From the lowest to the highest quartile of linolenic acid intake, the prevalence odds ratio (95% CI) of a carotid plaque was 1.0 (reference), 0.47 (0.30, 0.73), 0.38 (0.22, 0.66), and 0.49 (0.26, 0.94), respectively, in a model that adjusted for age, sex, energy intake, waist-to-hip ratio, education, field center, smoking, and the consumption of linoleic acid, saturated fat, fish, and vegetables. Linoleic acid, fish long-chain fatty acids, and fish consumption were not significantly related to carotid artery disease. Linolenic acid was inversely related to thickness of the internal and bifurcation segments of the carotid arteries but not to the common carotid artery.

 CONCLUSION: Higher consumption of total linolenic acid is associated with a lower prevalence odds of carotid plaques and with lesser thickness of segment-specific carotid intima-media thickness.

Relation between dietary linolenic acid and coronary artery disease in the National Heart, Lung, and Blood Institute Family Heart Study.

Djousse L, Pankow JS, Eckfeldt JH, Folsom AR, Hopkins PN, Province MA, Hong Y, Ellison RC.

Section of Preventive Medicine and Epidemiology, Evans Department of Medicine, the School of Medicine, Boston University.

BACKGROUND: Epidemiologic studies suggest that a higher consumption of eicosapentaenoic acid and docosahexaenoic acid is associated with a reduced risk of cardiovascular disease. Studies in humans and animals also reported an inverse association between alpha-linolenic acid and cardiovascular disease morbidity and mortality.

OBJECTIVE: We examined the relation between dietary linolenic acid and prevalent coronary artery disease (CAD).

DESIGN: We studied 4584 participants with a mean (+/-SD) age of 52.1 +/- 13.7 y in the National Heart, Lung, and Blood Institute Family Heart Study in a cross-sectional design. Participants' diets were assessed with a semiquantitative food-frequency questionnaire. For each sex, we created age- and energy-adjusted quintiles of linolenic acid, and we used logistic regression to estimate prevalent odds ratios for CAD.

RESULTS: From the lowest to the highest quintile of linolenic acid, the prevalence odds ratios of CAD were

 1.0, 0.77, 0.61, 0.58, and 0.60 for the men (P for trend = 0.012) and

 1.0, 0.57, 0.52, 0.30, and 0.42 for the women (P for trend = 0.014)

after adjustment for age, linoleic acid, and anthropometric, lifestyle, and metabolic factors. Linoleic acid was also inversely related to the prevalence odds ratios of CAD in the multivariate model (0.60 and 0.61 in the second and third tertiles, respectively) after adjustment for linolenic acid.

The combined effect of linoleic and linolenic acids was stronger than the individual effects of either fatty acid.

CONCLUSIONS: A higher intake of either linolenic or linoleic acid was inversely related to the prevalence odds ratio of CAD. The 2 fatty acids had synergistic effects on the prevalence odds ratio of CAD.

NOTA: I range dei quintili  del consumo giornaliero di ALA, erano:

         MASCHI                FEMMINE                                   Rapporto ALA:LA            

I           0,53 (0,19-0,97)       0,46 (0,13-0,84)  gr/g                0,08 (M)    0,08 (F)

II          0,67                        0,58     gr/g 

III         0,78                        0,65     gr/g

IV        0,90                        0,76     gr/g

V         1,14 (0,55-3,48)       0,96 (0,48-2,29)   gr/g                0,11 (M)     0,12 (F)

E' INTERESSANTE NOTARE COME I BENEFICI MAGGIORI SI OTTENGANO AUMENTANDO  LA QUANTITA'  DI ALA E LA  ED IL RAPPORTO ALA:LA

British Medical Journal, July 1996
Dietary fat and risk of coronary heart disease in men: cohort follow up study in the United States.
Ascherio A, Rimm EB, Giovannucci EL, Spiegelman D, Stampfer M, Willett WC.
Harvard School of Public Health, Boston, MA 02115, USA.

OBJECTIVE--To examine the association between fat intake and the incidence of coronary heart disease in men of middle age and older. 
DESIGN--Cohort questionnaire study of men followed up for six years from 1986. 
SETTING--The health professionals follow up study in the United States. 
SUBJECTS--43 757 health professionals aged 40 to 75 years free of diagnosed cardiovascular disease or diabetes in 1986. 
MAIN OUTCOME MEASURE--Incidence of acute myocardial infarction or coronary death. 
RESULTS--During follow up 734 coronary events were documented, including 505 non-fatal myocardial infarctions and 229 deaths. After age and several coronary risk factors were controlled for significant positive associations were observed between intake of saturated fat and risk of coronary disease. For men in the top versus the lowest fifth of saturated fat intake (median = 14.8% v 5.7% of energy) the multivariate relative risk for myocardial infarction was 1.22 (95% confidence interval 0.96 to 1.56) and for fatal coronary heart disease was 2.21 (1.38 to 3.54). After adjustment for intake of fibre the risks were 0.96 (0.73 to 1.27) and 1.72 (1.01 to 2.90), respectively. Positive associations between intake of cholesterol and risk of coronary heart disease were similarly attenuated after adjustment for fibre intake.
Intake of linolenic acid 18:3 n3 (ALA) was inversely associated with risk of myocardial infarction; this association became significant only after adjustment for non-dietary risk factors and was strengthened after adjustment for total fat intake (relative risk 0.41 for a 1% increase in energy, P for trend < 0.01).

NOTA: 1 gr di ALA = 9 Kcal, dunque un incremento pari all’1 % del fabbisogno energetico quotidiano equivale a circa 1,8-2,5 gr al giorno

CONCLUSIONS--These data do not support the strong association between intake of saturated fat and risk of coronary heart disease suggested by international comparisons. They are compatible, however, with the hypotheses that saturated fat and cholesterol intakes affect the risk of coronary heart disease as predicted by their effects on blood cholesterol concentration. 
They also support a specific preventive effect of linolenic acid intake.

Am J Clin Nutr 1999 May;69(5):890-7 
Dietary intake of alpha-linolenic acid and risk of fatal ischemic heart disease among women.
Hu FB, Stampfer MJ, Manson JE, Rimm EB, Wolk A, Colditz GA, Hennekens CH, Willett WC.
Department of Nutrition, Harvard School of Public Health, Boston, MA 02115, USA. Frank.Hu@channing.harvard.edu

BACKGROUND: Experimental studies in laboratory animals and humans suggest that alpha-linolenic acid (18:3n-3) may reduce the risk of arrhythmia. 
OBJECTIVE: The objective was to examine the association between dietary intake of alpha-linolenic acid and risk of fatal ischemic heart disease (IHD). 
DESIGN: This was a prospective cohort study. The intake of alpha-linolenic acid was derived from a 116-item food-frequency questionnaire completed in 1984 by 76283 women without previously diagnosed cancer or cardiovascular disease.
RESULTS: During 10 y of follow-up, we documented 232 cases of fatal IHD and 597 cases of nonfatal myocardial infarction. 

After adjustment for age, standard coronary risk factors, and dietary intake of linoleic acid and other nutrients, a higher intake of alpha-linolenic acid was associated with a lower relative risk (RR) of fatal IHD; the RRs from the lowest to highest quintiles were 1.0, 0.99, 0.90, 0.67, and 0.55 (95% CI: 0.32, 0.94; P for trend = 0.01).

For nonfatal myocardial infarction there was only a modest, nonsignificant trend toward a reduced risk when extreme quintiles were compared (RR: 0.85; 95% CI: 0.61, 1.19; P for trend = 0.50).

NOTA: nel quintile più elevato, il consumo di ALA era 1,36 gr/g, quello più basso di  0,71 gr/giorno.

A higher intake of oil and vinegar salad dressing, an important source of alpha-linolenic acid, was associated with reduced risk of fatal IHD when women who consumed this food > or =5-6 times/wk were compared with those who rarely consumed this food (RR: 0.46; 95% CI: 0.27, 0.76; P for trend = 0.001). 
CONCLUSIONS: This study supports the hypothesis that a higher intake of alpha-linolenic acid is protective against fatal IHD. Higher consumption of foods such as oil-based salad dressing that provide polyunsaturated fats, including alpha-linolenic acid, may reduce the risk of fatal IHD.