EFFECT OF DIETARY LIPID MODIFICATION ON AUTONOMIC FUNCTION IN PREMENOPAUSAL WOMEN
A-M Pellizzer*1, S. Lim2, P.W. Kamen2, N.E. Straznicky1, H. Krum2.
1Austin Hospital, Heidelberg, Victoria, 2Monash University, Alfred Hospital, Prahran, Victoria.
Hyercholesterolaemia adversely affects compliance and distensibility of the peripheral vasculature, which may impair the sensitivity of vascular baroreceptor responsiveness to changes in systemic BP. In support of this, an inverse relationship has been demonstrated between LDL cholesterol (chol.) levels and heart rate variability (HRV), a measure of cardiac parasympathetic activity (PSA). However, no study has systematically examined the effect of plasma chol. Modification on autonomic function.
We studied the effects of short-term dietary lipid modification on autonomic function in 25 normotensive, non-smoking, pre-menopausal women of normal body weight with normal chol. Profiles. Subjects consumed either a low (25%) or high fat (40%) diet for 2 weeks in an open, randomised, crossover manner with a 2 week washout period. Baroreflex sensitivity (BRS) was determined non-invasively by gating beat-to-beat RR interval and continuous non-invasive BP recordings. HRV measures of PSA were obtained in the time (rMSSD) and frequency (LnHFP) domains. Both LDL and HDL cholesterol ¯ significantly (*p<0.05, Table) with ¯ dietary fat intake as did MAP (from 78.1±1.5 to 74.3±1.5 mmHg). There was a significant in rMSSD and LnHFP following low fat diet. BRS also following the low fat diet (p = NS). By multivariate analysis, these changes in autonomic status were independent of body weight or OCP use.
|
LDL (mmol/l) |
HDL (mmol/l) |
Wt (kg) |
rMSSD (ms) |
LnHFP (ms2) |
BRS (ms/mmHg) |
|
|
High fat |
2.7±0.1 |
1.3±0.1 |
62.6±8.5 |
29.6±3.4 |
4.4±0.2 |
13.9±2.2 |
|
Low Fat |
2.2±0.1* |
1.1±0.1* |
62.3±8.3 |
38.8±6.4* |
4.8±0.3* |
16.9±3.2 |
Therefore, short-term dietary lipid modification PSA in healthy pre-menopausal women. These beneficial effects of lipid-lowering on autonomic function may be of prognostic significance in cardiovascular disease states characterised by autonomic dysfunction. More profound lipid-lowering (using statin therapy) may result in even greater autonomic effects and is being investigated.
