Impact of Cashew Nuts in the Human Diet: Measured Energy Value and Effects on Cardiovascular Disease Risk Factors

Study Overview
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Brief Summary
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This study evaluates the effect of cashew nut consumption on traditional and emerging markers of cardiovascular disease (CVD) risk and determines the usable energy content of a serving of cashew nuts for accurate food labelling.

Detailed Description
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The cardioprotective effects of nuts have been well documented in the scientific literature; however, most of the research has been done with almonds, walnuts, and pistachios, while studies with cashew nuts are lacking. In addition to the cardiovascular literature, our recent studies measuring the metabolizable energy of nuts have demonstrated that the measured energy value of almonds, pistachios, and walnuts is lower than that predicted using the Atwater factors. However, the measured energy value of cashew nuts is unknown. There are two distinct aims of this study - determining the effects of cashew nut consumption on risk factors of CVD, and determining the energy value of cashew nuts in the human diet. The cardiovascular effects of cashew nuts will be determined by measuring both traditional and emerging risk factors. The metabolizable energy value of cashew nuts will be calculated based on the chemical composition and energy content of the consumed diet and excreta. This will provide a better estimate of the energy value than simply calculating energy value based on Atwater factors.

Conditions
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Healthy Volunteers

Intervention / Treatment
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* Other: Base Diet
* Other: Base Diet with Cashew Nuts


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI between 20 and 38 kg/m2 Fasting glucose ≤ 126 mg/dL Blood pressure ≤ 160/100 mm Hg Exclusion Criteria: Presence of kidney disease, liver disease, gout, hyperthyroidism, untreated or unstable hypothyroidism, certain cancers, gastrointestinal disease, pancreatic disease, other metabolic diseases, or malabsorption syndromes Use of cholesterol lowering medication Use of medication to treat hypertension for less than 6 months Active cardiovascular disease (such as a heart attack or procedure within the past six months or participation in a cardiac rehabilitation program within the last six months, stroke, or history/treatment for transient ischemic attacks in the past six months, or documented history of pulmonary embolus in the past six months) Women who have given birth during the previous 12 months Pregnant women or women who plan to become pregnant or become pregnant during the study Lactating women Type 2 diabetes Use of prescription or over-the-counter antiobesity medications or supplements (e.g., phenylpropanolamine, ephedrine, caffeine, during and for at least 6 months prior to the start of the study) or history of a surgical intervention for obesity Smokers or other tobacco users (during 6 months prior to the start of the study) History of eating disorders or other dietary patterns which are not consistent with the dietary intervention (e.g., vegetarians, very low fat diets, high protein diets) Known (self-reported) allergy or adverse reaction to cashew nuts or other nuts Unable or unwilling to give informed consent or communicate with study staff Self-report of alcohol or substance abuse within the past 12 months and/or current acute treatment or rehabilitation program for these problems (long-term participation in Alcoholics Anonymous is not an exclusion) Other medical, psychiatric, or behavioral factors that in the judgment of the Principal Investigator may interfere with study participation or the ability to follow the intervention protocol

Ages Eligible for Study
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Minimum Age: 25 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Control<br>Participants will receive a controlled diet (base diet), typical of an American diet, with 0 g/day of cashew nuts (control). | Other: Base Diet<br>* Participants will receive a controlled diet with 0 g/d of cashew nuts. Meals will be prepared using traditional American foods with a macronutrient composition representative of a typical American diet.<br>|
| Active Comparator: Cashew<br>Participants will receive a controlled diet, typical of an American diet, with 42 g/day of cashew nuts (base diet with cashew nuts). | Other: Base Diet with Cashew Nuts<br>* Participants will receive a controlled diet with 42 g/d of cashew nuts. Meals will be prepared using traditional American foods with a macronutrient composition representative of a typical American diet.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in lipid/lipoprotein profile will be measured in blood | The following will be measured in the blood on 2 consecutive days at the beginning and end of each 4-week diet period: lipids and lipoproteins, apolipoproteins, lipoprotein particle number/size, and proprotein convertase subtilisin/kexin type 9 (PCSK9). | Week 0, end of diet period 1 (week 4), beginning of diet period 2 (week 6), end of diet period 2 (week 10) | 
| Metabolizable energy will be measured based on energy content of the consumed diet and excreta | The measured metabolizable energy value of cashew nuts will be calculated based on the energy content of the consumed diet and excreta. | Second week of diet period 1 (week 2) | 
| Metabolizable energy will be measured based on energy content of the consumed diet and excreta | The measured metabolizable energy value of cashew nuts will be calculated based on the energy content of the consumed diet and excreta. | Second week of diet period 2 (week 8) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pulse Wave will be measured using Sphygmocor EXCEL | Pulse wave analysis and pulse wave velocity will be conducted. | Week 0, end of diet period 1 (week 4), beginning of diet period 2 (week 6), end of diet period 2 (week 10) | 
| Markers of vascular health will be measured in blood | Adhesion molecules and endothelin-1 will be measured in the blood. | Week 0, end of diet period 1 (week 4), beginning of diet period 2 (week 6), end of diet period 2 (week 10) | 
| Digestibility (%) will be calculated as (intake - excreted)/intake | Fat, protein, and fiber digestibility will be calculated (%) and the effect of cashew nuts on nutrient digestibility (%) will be assessed. | Second week of diet period 1 (week 2), second week of diet period 2 (week 8) | 
| Change in systemic inflammation will be measured in blood | Markers of systemic inflammation will be measured, such as IL-6, TNF-alpha, serum amyloid A, and CRP. | Week 0, end of diet period 1 (week 4), beginning of diet period 2 (week 6), end of diet period 2 (week 10) | 
| Change in hemostasis will be measured in blood | Fibrinogen and factor VII will be measured in the blood. | Week 0, end of diet period 1 (week 4), beginning of diet period 2 (week 6), end of diet period 2 (week 10) |