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Completed

NCT Number: NCT03227497

Dietary Intake of Whole Walnuts in Adult Subjects Under Low Cardiovascular Risk

This cross-over study investigates health effects of dietary intake of whole walnuts towards cardiovascular risk factors in adults under low cardiovascular risk.

Investigators hypothesize that daily intake of whole nuts as a replacement meal, would improve cardiovascular risk factors, including traditional risk factors and molecular biomarkers.

The participants are randomly assigned to receive either study treatment, or no treatment, and are crossed after five weeks.

The study subjects are instructed to continue with their habitual diet and physical activity.

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Key information

Conditions

Cardiovascular Risk Factor Cardiovascular Diseases Glucose Metabolism Disorders Hyperinsulinism Hypertension Insulin Resistance Metabolic Diseases Metabolic Syndrome Nutritional and Metabolic Diseases Vascular Diseases

Age range

30 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Center of Research Excellence in Nutrition and Metabolism, Institute for Medical Research, University of Belgrade

Belgrade, 11000, Serbia

About this study

Recent literature data raise important questions on the beneficial effect of dietary fats. Dietary intake of nuts, although with high caloric burden, is however characterized with high intake of fatty acids with known beneficial health effects. Those fatty acids include mono- (MUFA) and polyunsaturated fatty acids (PUFA), to whom beneficial health effects are ascribed.

Among nuts, walnuts are characterized with comparatively high levels of MUFA and PUFA, especially content of alpha-linolenic PUFA, considered essential fatty acid, since not synthesized endogenously in humans. Dietary intake of alpha-linolenic acid is shown to be inversely related with cardiovascular risk factors, both in interventional studies and epidemiological cohorts. Molecular background of alpha-linolenic actions is bidirectional, and includes the action itself, as well as beneficial endogenous conversion towards long-chain fatty acids, including eicosapentaenoic and docosahexaenoic fatty acid.

Although high caloric intake is indicated with intake of walnuts, literature data suggest that consumption of walnuts does not increase body weight.

Dietary intake of walnuts has been shown to decrease cholesterol fractions, triglycerides and apolipoproteins in adult population. Also, consumption of walnuts was associated with decrease in blood pressure.

The study design is cross-over, controlled, randomized nutritional intervention. The participants are randomly assigned to receive either study treatment, or no treatment, and are crossed after five weeks.

The study subjects are instructed to continue with their habitual diet and physical activity. Additionally, study subjects are instructed to avoid walnuts and nuts other then study treatment, during the complete study period of 10 weeks.

Sample size calculation was conducted by use of online calculators, and was based on the low density lipoprotein (LDL) cholesterol. Namely, in order to achieve decrease in 0.5 mmol/L, in a sample with projected standard deviation of 0.7 mmol/L, and type I and II errors being 0.2 and 0.05, respectively, 62 subjects are needed.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Presence of at least one of the following criteria, formerly assessed through routine medical examination:

  • dyslipidemia, defined as the presence of either: elevated total cholesterol (>5.2 mmoL/L), and/or elevated LDL-cholesterol (>3.4 mmoL/L), and/or elevated triglycerides (>1.7 mmoL/L), and/or decreased HDL-cholesterol (<1.6 mmoL/L)
  • elevated blood pressure (systolic/diastolic ≥120/80 mmHg), or regular anti-hypertension therapy

Exclusion criteria

  • presence of allergy on any nuts
  • presence of any chronic disease, excluding following conditions: hypertension and diabetes mellitus type 2
  • smoking
  • statin therapy
  • pregnancy and/or lactation

Treatment and study plan

Whole Walnuts

Dietary Supplement

Intervention arm includes whole walnuts taken as dietary replacement meal during the day, and between breakfast and lunch, and/or lunch and dinner. Importantly, none of the main meals, including breakfast, lunch and dinner are to be replaced by study intervention, and the study subjects are instructed to do so. Walnuts are provided with the same producer at the Belgrade market.

Primary outcomes

  1. Changes in LDL-cholesterol

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in LDL-cholesterol measured by clinical bio-analyzer from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

  2. Changes in Systolic Blood Pressure

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in Systolic Blood Pressure, from baseline to endpoint, measured office-based at the following timepoints: 0 (baseline), 5 and 10 weeks.

  3. Changes in Diastolic Blood Pressure

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in Diastolic Blood Pressure from baseline to endpoint, measured office-based at the following timepoints: 0 (baseline), 5 and 10 weeks.

Secondary outcomes

  1. Changes in HDL-cholesterol

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in HDL-cholesterol measured by clinical bio-analyzer from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

  2. Changes in total cholesterol

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in total cholesterol measured by clinical bio-analyzer from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

  3. Changes in triglycerides

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in triglycerides measured by clinical bio-analyzer from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

  4. Changes in glucose metabolism biomarkers

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in glucose biomarkers measured by clinical bio-analyzer from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

  5. Changes in renal function parameters

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in renal function parameters measured by clinical bio-analyzer from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

  6. Changes in liver function parameters

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in liver function parameters measured by clinical bio-analyzer from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

  7. Changes in body weight

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in body weight measured by bio-impedance analyzer, from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

  8. Changes in waist circumference

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in waist circumference, from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

  9. Changes in percent of total body fat

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in percent of total body fat measured by bio-impedance analyzer, from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

  10. Level of Physical Activity

    Time frame: Baseline

    Level of physical activity is assessed by use of standardized Physical Activity Questionnaire.

  11. Psychological parameters

    Time frame: 5 weeks

    Psychological parameters are assessed by use of standardized questionnaire for self-assessment of psychological implications of daily activities related to cardiovascular health .

  12. Changes in hematological parameters

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in hematological, from baseline to endpoint, measured by hematological clinical analyzer at the following timepoints: 0 (baseline), 5 and 10 weeks.

  13. Changes in number of leukocyte cells

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in number of leukocyte cells, from baseline to endpoint, measured by hematological clinical analyzer at the following timepoints: 0 (baseline), 5 and 10 weeks.

  14. Changes in total caloric intake

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in total caloric intake, from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

    Total caloric intake is measured by use of standardized dietary questionnaire namely 24-hour Dietary Recall.

  15. Changes in caloric intake of fats

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in caloric intake of fats, from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

    The caloric intake is measured by use of standardized dietary questionnaire, namely 24-hour Dietary Recall.

  16. Changes in caloric intake of carbohydrates

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in caloric intake of carbohydrates, from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

    The caloric intake is measured by use of standardized dietary questionnaire, namely 24-hour Dietary Recall.

  17. Changes in caloric intake of vitamin D

    Time frame: Baseline, 5 weeks, 10 weeks

    Changes in caloric intake of vitamin D, from baseline to endpoint, measured at the following timepoints: 0 (baseline), 5 and 10 weeks.

    The caloric intake is measured by use of standardized dietary questionnaire, namely 24-hour Dietary Recall.

Sponsors and collaborators

Lead sponsor

University of Belgrade

Other

Collaborators

  • Centre of Research Excellence in Nutrition and Metabolism

Registry information

Official study title

Investigation of Health Effects of Dietary Intake of Whole Walnuts in Adult Subjects Under Low Cardiovascular Risk Towards Established and Molecular Cardiovascular Risk Factors

Acronym: FitALA

Important dates

Study start
2017
Primary completion
2017
Study completion
2017
First posted
Jul 24, 2017
Registry last updated
Jul 24, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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