Dietary fatty acids and risk factors for coronary heart disease : controlled studies in healthy volunteers

P.L. Zock

Research output: Thesisinternal PhD, WU

Abstract

<p>High levels of LDL cholesterol, blood pressure and Lp(a), and low levels of HDL cholesterol increase the risk for coronary heart disease (CHD). This thesis describes the effects of dietary fatty acids on these risk factors. In each of three trials we fed diets with tailored fatty acid composition to about 60 healthy men and women. Each diet within a trial was supplied to every volunteer for 3 weeks.<p>In the <strong><em>first study</em></strong><em></em> we compared the effects of monounsaturated <em>trans</em> fatty acids with those of linoleic acid, the fatty acid from which <em>trans</em> fatty acids are formed upon partial hydrogenation, and with those of stearic acid, a product of complete hydrogenation of linoleic acid. Relative to linoleic acid, both <em>trans</em> fatty acids and stearic acid raised LDL and lowered HDL cholesterol. Thus, partial as well as complete hydrogenation of linoleic acid produces fatty acids that unfavorably affect serum lipids relative to linoleic acid itself. <em>Trans</em> fatty acids and stearic acid did not influence blood pressure, but <em>trans</em> fatty acids modestly raised Lp(a).<p>The <em><strong>second study</strong></em> addressed the relative cholesterol-raising potentials of two specific saturates, myristic and palmitic acid. Relative to oleic acid, myristic acid was about 1.5 times as cholesterol-raising a's palmitic acid, due to increases in both LDL and HDL cholesterol. The differences between myristic and palmitic acid were statistically significant. However, both saturates caused high LDL cholesterol levels and raise the LDL to HDL cholesterol ratio.<p>In the <em><strong>third study</strong></em> we examined the effect of the positional distribution of fatty acids within dietary triglycerides. Two diets had identical total fatty acid composition, but a major contrast in fatty acid configuration. Total, LDL, and HDL cholesterol levels were the same on both diets. The position of the dietary fatty acids was partly reflected in fasting plasma lipids, but the fatty acid configuration had no important effect on lipoprotein levels.<p>In conclusion, monounsaturated <em>trans</em> fatty acids and the saturates myristic and palmitic acid have adverse effects on the serum lipoprotein risk profile for CHID. People at high risk for CHD should replace the hard fats in their diets by carbohydrates or unsaturated oils.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
Supervisors/Advisors
  • Hautvast, J.G.A.J., Promotor
  • Katan, M.B., Promotor
Award date11 Jan 1995
Place of PublicationS.l.
Publisher
Print ISBNs9789054853282
Publication statusPublished - 1995

Keywords

  • vascular diseases
  • blood disorders
  • cardiovascular diseases
  • cardiovascular disorders
  • fatty acids
  • food hygiene
  • blood lipids
  • lipoproteins
  • plant fats
  • plant oils
  • nutrition
  • cholesterol

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