Clinical trial NCT03227497: Dietary Intake of Whole Walnuts in Adult Subjects Under Low Cardiovascular Risk
Official 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
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Cardiovascular Risk Factor
Metabolic Syndrome
Hypertension
Keywords: Blood Pressure
Cholesterol
Triglycerides
Walnuts
Lead sponsor: University of Belgrade
Sponsor class: OTHER
Collaborators: name: Centre of Research Excellence in Nutrition and Metabolism
First posted: 2017-07-24
Enrollment: 52
Sex: ALL
Minimum age (years): 30
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: This study is a randomized, cross-over, controlled, 5-week nutritional intervention, investigating health effects of dietary intake of whole walnuts, as a replacement meal within habitual diet and lifestyle.

At the beginning of the study, half of the study subjects are randomly assigned to a treatment arm with walnut consumption, or control arm without study intervention. Treatment arm considers consumption of pre-packed 56 g of whole walnuts daily, as a replacement meal. After 5 weeks, study subjects are crossed, for additional 5 weeks. At the beginning of the study, all subjects are instructed to continue with their habitual diet and physical activity during the study period of 10 weeks.
Primary purpose: PREVENTION

Brief summary: 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.

Detailed description: 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.

Eligibility criteria: 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

Primary outcomes:
measure: Changes in LDL-cholesterol
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in Systolic Blood Pressure
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in Diastolic Blood Pressure
timeFrame: Baseline, 5 weeks, 10 weeks
Secondary outcomes:
measure: Changes in HDL-cholesterol
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in total cholesterol
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in triglycerides
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in glucose metabolism biomarkers
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in renal function parameters
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in liver function parameters
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in body weight
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in waist circumference
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in percent of total body fat
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Level of Physical Activity
timeFrame: Baseline
measure: Psychological parameters
timeFrame: 5 weeks
measure: Changes in hematological parameters
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in number of leukocyte cells
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in total caloric intake
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in caloric intake of fats
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in caloric intake of carbohydrates
timeFrame: Baseline, 5 weeks, 10 weeks
measure: Changes in caloric intake of vitamin D
timeFrame: Baseline, 5 weeks, 10 weeks
Other outcomes:
Locations:
city: Belgrade
country: Serbia
facility: Center of Research Excellence in Nutrition and Metabolism, Institute for Medical Research, University of Belgrade
Study officials:
affiliation: Center of Research Excellence in Nutrition and Metabolism, Institute for Medical Resaerch
name: Maria Glibetic, Prof
role: PRINCIPAL_INVESTIGATOR
References: