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Low-carbohydrate Diet and Low-Density Lipoprotein - Cholesterol (LDL-c) Interindividual Variability (REPETO)

25. juni 2026 oppdatert av: Bruno Spellanzon, University of Bath

Exploring True Interindividual Heterogeneity of Cardiovascular Disease (CVD) Risk Factors in Response to Low-carbohydrate Diets Using a Replicate Crossover Randomised Controlled Trial

Ketogenic diets are very low-carbohydrate diets that increase hepatic production of ketone bodies, which have several effects as substrates and signals. Ketogenic diets are used to manage some conditions (e.g., drug-resistant epilepsy), and their potential for managing many other conditions (e.g., cancer) is being actively explored. Indeed, the British Dietetic Association acknowledge the potential for ketogenic diets to improve glycaemic control to a greater extent than some other diets in people with type 2 diabetes. A lower fasting glucose is also relevant to future mortality in people without diabetes. Ketogenic diets are popular in the general population, with up to 15% of the UK following a low-carbohydrate diet. There is, therefore, great interest in ketogenic diets amongst people with and without health conditions. However, although the diet shows promising results in improving blood sugar levels, it has also shown to increase low-density lipoprotein-cholesterol (LDL-c) in some individuals, which has been linked to increased cardiovascular health risks. The aim of this project is to find the potential for personalised use of (or guidance to avoid) ketogenic diets for cardiovascular disease risk. To do that the investigators will ask participants to replicate 24 hours of a ketogenic diet and a control diet thrice each. This will allow the investigators to find variability between responses and have a better idea of individuals who could benefit (or not) from following the ketogenic diet.

Studieoversikt

Status

Rekruttering

Forhold

Detaljert beskrivelse

The study will be a controlled feeding replicate randomised controled trial with 3 cycles, each involving the pair of diets [low carbohydrate (K) and control (C) diets]. There will be 6 x 1-day periods (3 days low carbohydrate and 3 days control). Twenty individuals (body mass index: 18.5-35 kg/m2) will be recruited and randomised into one of the 8 possible sequences:

  1. KC KC KC
  2. KC KC CK
  3. KC CK KC
  4. KC CK CK
  5. CK CK CK
  6. CK CK KC
  7. CK KC CK
  8. CK KC KC A week before the interventions start, participants will visit the laboratory so that the investigators can perform indirect calorimetry and collect a blood sample for genotyping. During the week before the interventions, participants will wear activity monitors to determine habitual physical activity. Before each visit, participants will be asked to come to the lab in a rested and overnight fasted state. During the first trial visit, participants will have a dual-energy X-ray absorptiometry (DEXA) body scan to determine body composition. During all 12 study visits the investigators will perform a venepuncture in an antecubital vein and will collect 20 mL of blood.

Additionally, the investigators will also collect urine samples. After odd visits (1st, 3rd, 5th, 7th, 9th and 11th), participants will be supplied with their respective meals for the day (low carbohydrate or control) and will be asked to not eat anything else during the day.

Finally there will be a wash-out period of 6 days between laboratory visits. To keep consistency between trial days, participants will be asked to replicate physical activity levels performed during the 24 hours before the first trial, and during diet day (before second visit), so that these can be replicated for the following visits.

Studietype

Intervensjonell

Registrering (Antatt)

20

Fase

  • Ikke aktuelt

Kontakter og plasseringer

Denne delen inneholder kontaktinformasjon for de som utfører studien, og informasjon om hvor denne studien blir utført.

Studiekontakt

  • Navn: Bruno Spellanzon, PhD candidate
  • Telefonnummer: 447769407954
  • E-post: bs954@bath.ac.uk

Studiesteder

    • Bath and North East Somerset
      • Bath, Bath and North East Somerset, Storbritannia, BA2 7AY
        • Rekruttering
        • University of Bath
        • Hovedetterforsker:
          • Javier Gonzalez, PhD
        • Ta kontakt med:
          • Bruno Spellanzon, PhD candidate
          • Telefonnummer: 447769407954
          • E-post: bs954@bath.ac.uk
        • Ta kontakt med:

Deltakelseskriterier

Forskere ser etter personer som passer til en bestemt beskrivelse, kalt kvalifikasjonskriterier. Noen eksempler på disse kriteriene er en persons generelle helsetilstand eller tidligere behandlinger.

Kvalifikasjonskriterier

Alder som er kvalifisert for studier

  • Voksen
  • Eldre voksen

Tar imot friske frivillige

Ja

Beskrivelse

Inclusion Criteria:

  • Age: >18 years
  • Body mass index: 18.5-35 kg·m-2
  • Low-Density Lipoprotein-cholesterol <4.9 mmol/L
  • Non-fasting triglycerides <2.3 mmol/L

Exclusion Criteria:

  • weight instability (>5% change in body mass within last 3 months)
  • smoker
  • diagnosis of hypercholesterolaemia or any other lipid-related disease
  • diagnosis of diabetes
  • diagnosis of atherosclerotic cardiovascular disease
  • elevated fasting glucose (>5.4 mmol/L)
  • dietary intolerances or allergies or to other study procedures
  • diagnosis of gastrointestinal disorders
  • any other condition/medication that could introduce bias to the study
  • already following a ketogenic diet
  • not willing to follow a ketogenic diet
  • unable to understand English language

Studieplan

Denne delen gir detaljer om studieplanen, inkludert hvordan studien er utformet og hva studien måler.

Hvordan er studiet utformet?

Designdetaljer

  • Primært formål: Grunnvitenskap
  • Tildeling: Randomisert
  • Intervensjonsmodell: Crossover-oppdrag
  • Masking: Ingen (Open Label)

Våpen og intervensjoner

Deltakergruppe / Arm
Intervensjon / Behandling
Annen: Sequence 1
Participants will follow a 1) low-carbohydrate diet, wash-out, 2) control diet, wash-out, 3) low-carbohydrate diet, wash-out, 4) control diet, wash-out, 5) low-carbohydrate diet, wash-out, 6) control diet
Diet will have macronutrients split with 50% carbohydrates, 15% protein and 35% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Diet will have macronutrients split with 8% carbohydrates, 15% protein and 77% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Annen: Sequence 2
Participants will follow a 1) low-carbohydrate diet, wash-out, 2) control diet, wash-out, 3) low-carbohydrate diet, wash-out, 4) control diet, wash-out, 5) control diet, wash-out, 6) low-carbohydrate diet
Diet will have macronutrients split with 50% carbohydrates, 15% protein and 35% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Diet will have macronutrients split with 8% carbohydrates, 15% protein and 77% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Annen: Sequence 3
Participants will follow a 1) low-carbohydrate diet, wash-out, 2) control diet, wash-out, 3) control diet, wash-out, 4) low-carbohydrate diet, wash-out, 5) control diet, wash-out, 6) low-carbohydrate diet
Diet will have macronutrients split with 50% carbohydrates, 15% protein and 35% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Diet will have macronutrients split with 8% carbohydrates, 15% protein and 77% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Annen: Sequence 4
Participants will follow a 1) low-carbohydrate diet, wash-out, 2) control diet, wash-out, 3) control diet, wash-out, 4) low-carbohydrate diet, wash-out, 5) low-carbohydrate diet, wash-out, 6) control diet
Diet will have macronutrients split with 50% carbohydrates, 15% protein and 35% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Diet will have macronutrients split with 8% carbohydrates, 15% protein and 77% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Annen: Sequence 5
Participants will follow a 1) control diet, wash-out, 2) low-carbohydrate diet, wash-out, 3) control diet, wash-out, 4) low-carbohydrate diet, wash-out, 5) control diet, wash-out, 6) low-carbohydrate diet
Diet will have macronutrients split with 50% carbohydrates, 15% protein and 35% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Diet will have macronutrients split with 8% carbohydrates, 15% protein and 77% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Annen: Sequence 6
Participants will follow a 1) control diet, wash-out, 2) low-carbohydrate diet, wash-out, 3) control diet, wash-out, 4) low-carbohydrate diet, wash-out, 5) low-carbohydrate diet, wash-out, 6) control diet
Diet will have macronutrients split with 50% carbohydrates, 15% protein and 35% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Diet will have macronutrients split with 8% carbohydrates, 15% protein and 77% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Annen: Sequence 7
Participants will follow a 1) control diet, wash-out, 2) low-carbohydrate diet, wash-out, 3) low-carbohydrate diet, wash-out, 4) control diet, wash-out, 5) control diet, wash-out, 6) low-carbohydrate diet
Diet will have macronutrients split with 50% carbohydrates, 15% protein and 35% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Diet will have macronutrients split with 8% carbohydrates, 15% protein and 77% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Annen: Sequence 8
Participants will follow a 1) control diet, wash-out, 2) low-carbohydrate diet, wash-out, 3) low-carbohydrate diet, wash-out, 4) control diet, wash-out, 5) low-carbohydrate diet, wash-out, 6) control diet
Diet will have macronutrients split with 50% carbohydrates, 15% protein and 35% fat. Also there will be a 0.66 ratio saturated:unsaturated fat
Diet will have macronutrients split with 8% carbohydrates, 15% protein and 77% fat. Also there will be a 0.66 ratio saturated:unsaturated fat

Hva måler studien?

Primære resultatmål

Resultatmål
Tiltaksbeskrivelse
Tidsramme
Fasted plasma Low-density lipoprotein cholesterol (LDL-C) concentrations
Tidsramme: Pre and post following each intervention/control diet for 24 hours

Variable will be used to establish whether there is true inter-individual heterogeneity in response to 24 hours of a low-carbohydrate diet.

Measured in mmol/L.

Pre and post following each intervention/control diet for 24 hours

Sekundære resultatmål

Resultatmål
Tiltaksbeskrivelse
Tidsramme
Fasted glucose plasma glucose concentration
Tidsramme: Pre and post following each intervention/control diet for 24 hours

Variable measured to establish whether there is true inter-individual heterogeneity in response to 24 hours of a low-carbohydrate diet.

Measured in mmol/L

Pre and post following each intervention/control diet for 24 hours

Samarbeidspartnere og etterforskere

Det er her du vil finne personer og organisasjoner som er involvert i denne studien.

Etterforskere

  • Hovedetterforsker: Javier Gonzalez, PhD, University of Bath

Studierekorddatoer

Disse datoene sporer fremdriften for innsending av studieposter og sammendragsresultater til ClinicalTrials.gov. Studieposter og rapporterte resultater gjennomgås av National Library of Medicine (NLM) for å sikre at de oppfyller spesifikke kvalitetskontrollstandarder før de legges ut på det offentlige nettstedet.

Studer hoveddatoer

Studiestart (Faktiske)

5. februar 2026

Primær fullføring (Antatt)

1. mars 2027

Studiet fullført (Antatt)

1. mars 2027

Datoer for studieregistrering

Først innsendt

5. mai 2026

Først innsendt som oppfylte QC-kriteriene

25. juni 2026

Først lagt ut (Faktiske)

30. juni 2026

Oppdateringer av studieposter

Sist oppdatering lagt ut (Faktiske)

30. juni 2026

Siste oppdatering sendt inn som oppfylte QC-kriteriene

25. juni 2026

Sist bekreftet

1. juni 2026

Mer informasjon

Begreper knyttet til denne studien

Legemiddel- og utstyrsinformasjon, studiedokumenter

Studerer et amerikansk FDA-regulert medikamentprodukt

Nei

Studerer et amerikansk FDA-regulert enhetsprodukt

Nei

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