Cardiovascular disease (CVD) is the number 1 disease to cause mortality worldwide and is associated with alterations in lipid metabolism. Apolipoproteins regulate lipoprotein characteristics and recent evidence has shown apolipoproteins (apo) to be important CVD risk predictors. Poor lifestyle habits can lead to unhealthy alterations in lipid metabolism. A low carbohydrate high fat (LCHF) diet has shown to improve lipid metabolism and metabolic health markers however; few studies have compared a LCHF diet to a high carbohydrate (HC), lower fat diet under ad libitum conditions, particularly their effect on apoC-III. The aims of this investigation was to measure the effect of a LCHF diet vs. a HC diet on apoC-III, apoA1, apoB and apoB/apoA1 in 16 healthy Caucasian adults aged 19-64. Ethics was approved from Liverpool John Moores University Research Ethics Committee (16/ELS/029) and was registered with ClinicalTrials.gov (Ref. NCT03257085). Participants randomly assigned to either a HC diet (the UK Eatwell guidelines; ≥50% of energy from carbohydrates) (n=8), or a LCHF diet (consume <50 g/day of carbohydrates) (n=8) provided plasma samples at 0, 4 and 8 weeks. ApoA1 and apoB1 was analysed by an automated chemistry analyser (Daytona, Randox Laboratories Ltd, UK) while apoC-III was analysed via ELISA (Thermo Fisher Ltd, USA). Factorial 2x3 ANOVA and ANCOVA (IBM SPSS 24®) was undertaken to investigate significant differences and to control for changes in variables due to visceral adipose tissue (VAT) and baseline measures. Post 8 weeks, ApoC-III (LCHF, Δ-5.58 +/- 9.14 mg/dl; HC, Δ0.88 +/- 11.56 mg/dl, P=0.212), apoB (LC, Δ0.14 +/- 13.91 mg/dl; HC, Δ4.6 +/- 12.67 mg/dl, P=0.539), apoA1 (LCHF, Δ2.7 +/- 13.82 mg/dl; HC, Δ1.71 +/- 23.79 mg/dl, P=0.888) and aopB/apoA1 (LCHF, Δ-0.1 +/- 0.12 mg/dl; HC, Δ0.1 +/- 0.09 mg/dl, P=0.795) showed no significant change in response to either diet. ANCOVA analysis with the baseline measure and VAT as a covariate, the adjusted mean change for apoC-III (LCHF, Δ-6.56 mg/dl; HC, Δ1.2 mg/dl, P=0.06), apoB (LCHF, Δ0.23 mg/dl; HC, Δ4.55 mg/dl, P=0.613), apoA1 (LCHF, Δ-3.27 mg/dl; HC, Δ6.8 mg/dl, P=0.386) and apoB/apoA1 (LCHF, Δ0.1 mg/dl; HC, Δ-0.01 mg/dl, P=0.788) still showed no significant difference between diets. Collectively, this preliminary study has shown that a LCHF diet does not appear to improve apolipoprotein profile; however, when accounting for other metabolic risk factors (i.e. VAT) it may reduce apoC-III levels (P=0.06) which may decrease CVD risk via very-low-density lipoprotein lowering but higher-powered studies are needed to confirm this finding.

P4-26-04 - The effect of a low carbohydrate high fat diet on apolipoproteins and cardiovascular risk.