Raise Your PUFA and Live Longer

Summarized by Robert W. Griffith, MD
May 25, 2005

Introduction

Fat is largely made up of fatty acids, which come in three sorts - the good, the bad, and the ugly:

• Polyunsaturated fatty acids (PUFA) are 'good', and include the omega-3 fatty acids that are especially good; monounsaturated fatty acids (MUFA) are also excellent.
• Saturated fatty acids (SAFA) are 'bad'.
• Trans fatty acids are 'ugly' - they are man-made or processed fats used in baking (see first link below).

Doctors have been telling us for years that we should eat fewer SAFA and more PUFA. However, proof of the value of this has been largely lacking, until the publication of a new Finnish study in the Archives of Internal Medicine. Just reducing fat intake without paying attention to the quality of the fat is not going to do it. So it's helpful to have evidence that shows the best way to improve one's chances of living longer.

What was done

A sample of men living in eastern Finland was assembled, using groups composed of people aged 42, 48, 54, and 60 in 1984. Those with a history of cardiovascular disease, diabetes, or cancer were excluded, as well as those who failed to provide dietary information and serum for fatty acid analyses. This left 1551 men for the final analysis.

Four-day food questionnaires were used at baseline (1984) to assess the dietary intake of PUFA, SAFA, MUFA, linolenic, and alpha-linolenic fatty acids. (Linolenic fatty acid comprised about 75% of PUFA intake.) Intake of fatty acids and fiber was calculated in grams per day.

Blood taken at baseline was analyzed for fatty acids, other blood lipids, insulin, glucose, and C-reactive protein (CRP). A full medical history and information on lifestyle factors (alcohol, smoking, exercise, etc) was obtained at this time.

All deaths of participants, recorded through the Finnish national death registry, were classified as to being due to coronary heart disease, stroke, or some other cause.

What was found

During the 15-year follow-up period 225 men died of any cause, and 88 died of cardiovascular disease (stroke or heart attack). Smoking, high blood pressure, overweight, and raised CRP levels were associated with increased deaths - both any-cause and cardiovascular disease.

Men with lower dietary intakes of PUFA, linolenic, and alpha-linolenic acid had a significantly higher cardiovascular and overall mortality. Total fat, SAFA, MUFA, and cholesterol intake were not linked to increased death rates.

The size of the effect was quite big. When the participants were classified into three groups according to the level of their dietary intake of PUFA, those in the upper third had a 62% lower risk of cardiovascular mortality than those in the lower third.

Men with serum linolenic acid and serum PUFA in the upper third of participants were up to 3-times less likely to die from cardiovascular disease than those in the lower third.

What this study shows

Middle-aged men who consumed diets with higher PUFA and linolenic fatty acid content were shown to be less likely to die, particularly from cardiovascular disease, than those who ate less of these fats. The lesson is clear: we should all aim to improve the quality of the fat we eat, rather than just reduce total fat intake. Eat no trans fats, plenty of omega-3 fatty acids (salmon, herring, mackerel), more MUFA and PUFA (olive and canola oil, vegetable oils), and less SAFA (egg yolk, dairy, meats). And, of course, plenty of dark-colored veggies, fruits, and nuts.

Source

• Prediction of cardiovascular mortality in middle-aged men by dietary and serum linolenic and polyunsaturated fatty acids. DE. Laaksonen, K. Nyyssonen, L. Nishkanan,  et al., Ach Intern Med, 2005, vol. 165, pp. 193--199

Related Links
Watch the Trans Fatty Acids - They Can Do Harm!
Linolenic Acid Intake Linked to Heart Health
Moderate-Fat Diets for Weight Loss?

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