RECENT INSIGHTS INTO DIETARY FATS AND CARDIOVASCULAR DISEASE

Authors

  • Simon B. Dimmitt

    Corresponding author
    1. Department of Medicine, University of Western Australia, Royal Perth Hospital, Wellington Street, Perth, Western Australia, Australia
      Dr S. B. Dimmitt, University Department of Medicine, Royal Perth Hospital, Box X2213 GPO Perth, WA 6001, Australia.
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Dr S. B. Dimmitt, University Department of Medicine, Royal Perth Hospital, Box X2213 GPO Perth, WA 6001, Australia.

SUMMARY

1. Fat deposition in the arterial intima is fundamental to the atheroma process. Circulating lipoproteins are thought to be the source of much of the deposited fat. The interplay of dietary fat has not been fully clarified.

2. Observational studies have furnished evidence of relationships between the different dietary fats and clinical cardiovascular events. In these, total fat and in particular, saturated fat appear culprit. Mono-unsaturated (MUFA) and polyunsaturated (PUFA) fats have less consistent relationships with cardiovascular disease, though all classes of fatty acid are found in atheroma.

3. Comparing the effects on lipoproteins of saturates, mono-unsaturates and polyunsaturates, they all increase high density lipoproteins (HDL) and reduce triglycerides when substituted isocalorically for carbohydrate. Saturates increase low density lipoproteins (LDL), while PUFA > MIJFA reduce LDL.

4. Upon oxidative modification, lipoproteins are more liable to arterial deposition and, in vitro at least, LDL oxidizability is enhanced by enrichment with PUFA.

5. Trans-MUFA have some unique properties in that they somewhat resemble saturates and seem to predispose to coronary disease, quite possibly because of their adverse effects on LDL, HDL and Lp(a) levels.

6. ω-3 fatty acids seem unique among the dietary fats in that they inhibit thrombosis and platelet aggregation, and can lower blood pressure.

7. The net effect of these various potential influences of fatty acids on atherogenesis in vivo is unclear. It may well be that all fats, with the exception of the ω-3 class, are detrimental with respect to atherogenesis. Modification of the diet, with particular attention to fat, has been demonstrated to reduce clinical coronary events in several studies. Restriction of all fats, save for that in fish, preferably along with weight reduction, appears desirable in order to effectively reduce cardiovascular disease risk.

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