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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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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.
Contributors
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- By Kumar Alagappan, Janet G. Alteveer, Kim Askew, Paul S. Auerbach, Katherine Bakes, Kip Benko, Paul D. Biddinger, Victoria Brazil, Anthony FT Brown, Andrew K. Chang, Alice Chiao, Wendy C. Coates, Jamie Collings, Gilbert Abou Dagher, Jonathan E. Davis, Peter DeBlieux, Alessandro Dellai, Emily Doelger, Pamela L. Dyne, Gino Farina, Robert Galli, Gus M. Garmel, Daniel Garza, Laleh Gharahbaghian, Gregory H. Gilbert, Michael A. Gisondi, Steven Go, Jeffrey M. Goodloe, Swaminatha V. Gurudevan, Micelle J. Haydel, Stephen R. Hayden, Corey R. Heitz, Gregory W. Hendey, Mel Herbert, Cherri Hobgood, Michelle Huston, Loretta Jackson-Williams, Anja K. Jaehne, Mary Beth Johnson, H. Brendan Kelleher, Peter G Kumasaka, Melissa J. Lamberson, Mary Lanctot-Herbert, Erik Laurin, Brian Lin, Michelle Lin, Douglas Lowery-North, Sharon E. Mace, S. V. Mahadevan, Thomas M. Mailhot, Diku Mandavia, David E. Manthey, Jorge A. Martinez, Amal Mattu, Lynne McCullough, Steve McLaughlin, Timothy Meyers, Gregory J. Moran, Randall T. Myers, Christopher R.H. Newton, Flavia Nobay, Robert L. Norris, Catherine Oliver, Jennifer A. Oman, Rita Oregon, Phillips Perera, Susan B. Promes, Emanuel P. Rivers, John S. Rose, Carolyn J. Sachs, Jairo I. Santanilla, Rawle A. Seupaul, Fred A. Severyn, Ghazala Q. Sharieff, Lee W. Shockley, Stefanie Simmons, Barry C. Simon, Shannon Sovndal, George Sternbach, Matthew Strehlow, Eustacia (Jo) Su, Stuart P. Swadron, Jeffrey A. Tabas, Sophie Terp, R. Jason Thurman, David A. Wald, Sarah R. Williams, Teresa S. Wu, Ken Zafren
- Edited by S. V. Mahadevan, Stanford University School of Medicine, California, Gus M. Garmel
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- Book:
- An Introduction to Clinical Emergency Medicine
- Published online:
- 05 May 2012
- Print publication:
- 10 April 2012, pp xi-xvi
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28 - Fever in children
- from Section 2 - Primary Complaints
- Edited by S. V. Mahadevan, Stanford University School of Medicine, California, Gus M. Garmel
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- Book:
- An Introduction to Clinical Emergency Medicine
- Published online:
- 05 May 2012
- Print publication:
- 10 April 2012, pp 393-404
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23 - Fever in children
- Swaminatha V. Mahadevan, Stanford University School of Medicine, California, Gus M. Garmel, Stanford University School of Medicine, California
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- Book:
- An Introduction to Clinical Emergency Medicine
- Published online:
- 27 October 2009
- Print publication:
- 26 May 2005, pp 353-364
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Summary
Scope of the problem
Pediatric fever is one of the more common presenting complaints to the emergency department (ED). The objective of ED evaluation of febrile children is to identify and treat the small subset of children who harbor life-threatening bacterial infections. A febrile infant is at risk for a variety of serious bacterial infections (SBIs), including bacteremia, meningitis, osteomyelitis, suppurative arthritis, skin and soft tissue infection, urinary tract infection, gastroenteritis, and pneumonia. Concurrently, an attempt is made to avoid the indiscriminate use of antibiotics in febrile children. The etiology of a child's fever in the majority of cases is an acute viral infection. Unfortunately, considerable overlap exists in the clinical appearance of a child with occult bacteremia (presence of pathogenic bacteria in the blood of a well-appearing febrile child without an identifiable focus of infection) and a child with fever due to a viral illness. As a result, the broad spectrum of advocated management practices for febrile children continues to be the subject of much research and controversy.
Pathophysiology
Fever results from body temperature elevation above normal circadian variation due to an increase in the hypothalamic thermoregulatory set point. A febrile response is thought to result from enhanced metabolic activity and is mediated by the release of pyrogens. These pyrogens (e.g., tumor necrosis factor, interleukin-1, and interferon) are released from host leukocytes, which in turn reset the temperature regulatory center in the hypothalamus.