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The effect of a low carbohydrate high fat diet on emerging biochemical markers of cardiometabolic risk
- Deaglan McCullough, Tanja Harrison, Katie Lane, Lynne Boddy, Farzad Amirabdollahian, Michael Schmidt, Kevin Enright, Claire Stewart, Ian Davies
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- Journal:
- Proceedings of the Nutrition Society / Volume 79 / Issue OCE2 / 2020
- Published online by Cambridge University Press:
- 10 June 2020, E530
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Worldwide, cardiovascular disease (CVD) is the number 1 cause of mortality and is associated with insulin resistance (IR). Emerging biomarkers such as FGF21 and adiponectin are associated with cardiometabolic risk. Low carbohydrate, high fat (LCHF) diets have been reported to reduce cardiometabolic risk markers; however, few studies have compared a LCHF diet vs. a high carbohydrate (HC), lower fat diet under ad libitum conditions on adiponectin and FGF21. The purpose of this study was to investigate the effects of an ad libitum LCHF vs. HC diet on IR, FGF21 and adiponectin in 16 healthy adults. Ethical approval: Liverpool John Moores University Research Ethics Committee (16/ELS/029); registered with ClinicalTrials.gov (Ref. NCT03257085). Participants were randomly assigned to a HC diet (n = 8, the UK Eatwell guidelines; ≥ 50% of energy from carbohydrates) or a LCHF diet (n = 8, consume < 50 g/day of carbohydrates). All provided plasma samples at 0, 4 and 8 weeks. FGF21 (R&D Systems) was analysed via ELISA and adiponectin, insulin and glucose were analysed via immunoassay technology (Randox Evidence Investigator™ Metabolic Syndrome Arrays I & II). Mann Whitney, Friedmans, Wilcoxon tests and 2×3 ANOVA (IBM SPSS 25®) were undertaken to investigate significant differences between and within groups. The homeostatic model assessment (HOMA) was used to calculate IR. FGF21 significantly (P = 0.04) decreased (Mdn, IQR:148.16, 78.51–282.02 to 99.4, 39.87–132.29 pg/ml) after 4 weeks and significantly (P = 0.02) increased (Mdn, IQR:167.38, 80.82–232.89 pg/ml) by 8 weeks vs. baseline with LCHF. No significant differences (P > 0.05) were observed between groups. Adiponectin was significantly (P = 0.03) different at week 4 only between groups. Adiponectin increased after 4 weeks (Mdn, IQR:13.44, 9.12–25.47 to 16.64, 11.96–21.51 ng/ml) but was only significantly (P = 0.03) different by 8 weeks vs. baseline in the HC group (Mdn, IQR:16, 10.8–27.43 ng/ml). Adiponectin remained unchanged (P = 0.96) in the LCHF group. HOMA significantly decreased with both diets after 8 weeks only (mean ± SD, LCHF: 2.9 ± 1.3 to 1.8 ± 0.8, HC: 2.5 ± 0.6 to 1.9 ± 0.6, P = 0.008) but was not significantly (P = 0.60) different between groups. These preliminary data reveal that while both diets improved insulin sensitivity, they may do so by different mechanisms. Future studies are warranted to investigate further, how a LCHF vs. HC diet affects FGF21 and adiponectin, and the subsequent regulation of IR. Furthermore, studies that extend these findings by determining the impact of LCHF vs. HC on peripheral metabolism to determine potential nutrition-mediated mechanisms of metabolic adaptation are warranted.
The effect of a low carbohydrate high fat diet on apolipoproteins and cardiovascular risk
- Deaglan McCullough, Tanja Harrison, Katie Lane, Lynne Boddy, Farzad Amirabdollahian, Michael Schmidt, Kevin Enright, Claire Stewart, Ian Davies
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- Journal:
- Proceedings of the Nutrition Society / Volume 79 / Issue OCE2 / 2020
- Published online by Cambridge University Press:
- 10 June 2020, E677
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- Article
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- You have access Access
- Export citation
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Apolipoproteins (apo) regulate lipoprotein characteristics and lipid metabolism. ApoC-III is a regulator of triglyceride-rich lipoprotein (TRL) metabolism and apolipoproteins are important biomarkers for cardiovascular disease (CVD) risk prediction. A low carbohydrate high fat (LCHF) diet improves cardiometabolic risk, especially via reduction of TRL. However, few studies have compared a LCHF vs. a high carbohydrate (HC), lower fat diet under ad libitum conditions on apoC-III levels. The objectives of this investigation were to measure the effect of a LCHF vs. a HC diet on apoC-III, apoA1, apoB and apoB/apoA1 in 16 healthy Caucasian adults aged 19–64. Ethical approval: Liverpool John Moores University Research Ethics Committee (16/ELS/029); registered with ClinicalTrials.gov (Ref. NCT03257085). Participants randomly assigned to a HC diet (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 apoB were analysed by an automated chemistry analyser (Daytona, Randox Laboratories Ltd, UK). ApoC-III was analysed via ELISA (Thermo Fisher Ltd, USA). Factorial 2×3 ANOVA and ANCOVA (IBM SPSS 25®) were undertaken to investigate significant differences and to control for variables influenced by baseline measures and visceral adipose tissue (VAT). Results show 0, 4, and 8 weeks respectively: ApoC-III (LCHF: 19.12 ± 9.14, 16.05 ± 7.95, 15.11 ± 3.17 mg/dl; HC: 22.13 ± 8.38, 28.22 ± 13.85, 22.22 ± 7.7 mg/dl) showed no significant (P = 0.319) change. No significant (P = 0.23) change was also observed in ApoB (LCHF: 107.25 ± 20.35, 111.38 ± 24.81, 111.43 ± 19.93 mg/dl; HC: 94.38 ± 20.79, 105.00 ± 20.13, 99.00 ± 29.09 mg/dl). Similarly apoA1 (LCHF: 158.71 ± 14.27, 166.50 ± 23.09, 173.00 ± 29.42 mg/dl; HC: 164.71 ± 30.25, 172.50 ± 29.44, 174.00 ± 32.83 mg/dl) showed no significant change (P = 0.76). This resulted in a relatively unchanged apoB/A1 throughout the study in both diets (P = 0.30). No significant (P > 0.05) differences were found after 4 weeks or between groups also. ANCOVA revealed a trend (P = 0.06) in apoC-III for a difference between groups (LCHF: Δ-6.6 mg/dl vs. HC: Δ1.2 mg/dl) after 8 weeks but no significant (P > 0.05) changes in other apolipoproteins were detected. These preliminary data reveal that a LCHF diet does not improve the apolipoprotein profile; however, when accounting for other metabolic risk factors (i.e. VAT) there was a trend towards lowering apoC-III levels (P = 0.06). Modulation of apoC-III may lead to improved lipid metabolism, but higher-powered studies are warranted before any improvement on CVD risk can be inferred.