Table 1

Characteristics of included randomised controlled trials examining the effect of nut consumption on inflammatory biomarkers and endothelial function

Citation and countrySample size (for analysis)Mean age, yearsMean BMI, kg/m2 PopulationDesignStudy duration, weeksNut typeNut doseComparison group detailsBackground dietOutcome of interest
Barbour et al,51 Australia61 (M: 29, F: 32)65±731±4OverweightX12Peanut (high oleic)M: 84 g, 6× week
F: 56 g, 6× week
No nutsHabitual dietCRP (mg/L)
Burns-Whitmore et al,52 USA20 (M: 4, F: 16)38±323±1HealthyX8Walnut28.4 g, 6× weekStandard egg, 6× week*Habitual dietCRP (ng/mL)‡, TNF-α (pg/mL), IL-6 (pg/mL), ICAM-1 (ng/mL)
Canales et al,53 Spain22 (M: 12, F: 10)54.8 (SEM: 2.0)29.6 (SEM: 0.7)Overweight with at least one risk factor for CVDX5Walnut150 g/week walnut paste integrated into steaks and sausagesLow-fat steaks and sausagesHabitual diet with substituted meat productsICAM-1 (μg/L)‡, VCAM-1 (μg/L)‡
Casas-Agustench et al,16 Lopez-Uriarte et al,38 Spain50 (M: 28, F: 22)I: 52.9±8.4
C: 50.6±8.4
I: 31.6±2.8
C: 30.0±3.3
MetSP12Mixed nuts (walnut, almond, hazelnut)30 g/day (15 g walnuts, 7.5 g almonds, 7.5 g hazelnuts)No nutsAmerican Heart Association dietary guidelinesCRP (mg/L), adiponectin (ng/mL)‡, IL-6 (ng/L)‡, ICAM-1 (μg/L)‡, VCAM-1 (μg/L)‡
Chen et al,54 USA45 (M: 18, F: 27)61.8±8.630.2±5.1CADX6Almond85 g/dayNo nutsNCEP Step 1 diet (isocaloric)CRP (mg/L), TNF-α (pg/mL), IL-6 (pg/mL), VCAM-1 (ng/mL), FMD (%)
Chiang et al,55 USA25 (M: 14, F: 11)33 (range 23–65)24.8 (range: 18.7–36.6)Normal to HLX4Walnut42.5 g per 10.1MJ (6× week)No nuts or fatty fish*American Dietary Guidelines (isocaloric)CRP(mg/L)‡,TNF-α(pg/mL),IL-6(pg/mL),ICAM-1(ng/mL)
Damasceno et al,36 Spain18 (M: 9, F: 9)56±1325.7±2.3HCX41.Walnut
2. Almond
1. 40–65 g/day walnuts
2. 50–75 g/day almonds§
35–50 g/day virgin olive oilMediterranean-style diet (isocaloric)CRP (mg/L), ICAM-1 (ng/mL), VCAM-1 (ng/mL)
Djousse et al,39 USA26 (M: 10,F: 16)¶I: 60.8±11.3
C: 68.8±10.9
I: 29.6±5.2 C: 33.5±8.7CAD or T2DMP12Walnut28 g/dayNo nutsHabitual diet with walnuts substituted for equivalent kJ itemsAdiponectin (μg/mL)
Gulati et al,19 India68 (M: 37, F: 31)42.5±8.230.9±7.5MetSP24Pistachio20% of total energy**Dietary guidelines for Asian IndiansDietary guidelines for Asian Indians, with pistachios substituted for diet componentsCRP(mg/L)‡,adiponectin(µg/mL)‡, TNF-α(pg/mL)
Hernandez-Alonso et al,20 Spain54 (M: 29, F: 25)55 (95% CI 53.4 to 56.8)28.9 (95% CI 28.2 to 29.6)PrediabeticX16Pistachio57 g/dayIntake of fatty foods adjusted to account for energy from pistachiosIsocaloric dietAdiponectin(µg/mL)‡, IL-6(pg/mL
Hu et al,49 Australia21 (M, F)††I: 62.4±8.8
C: 66.5±6.9
I: 82.2±10.8
C: 83.9±22.4§§‡‡
HealthyP6Brazil nut (plus green tea extract)18 g/day§§Green tea extract, no nutsHabitual dietCRP (mg/L)
Jenkins et al,56 Canada27 (M: 15, F: 12)64±925.7±3.0HLX4Almond73±3 g/day§§147±6 g/day muffins§§*NCEP step 2 diet (isocaloric)CRP (mg/L)
Kasliwal et al,40 India56 (M: 46, F:10) (randomised)
42 (completed)
8.1¶¶2.9¶¶C: 27.8 +4.7¶¶DLP12Pistachio40 g/day shelledNo nutsTherapeutic Lifestyle Change dietCRP (mg/L), FMD (%)
Katz et al,17 USA46 (M: 18, F: 28)57.4±11.933.2±4.4Overweight plus risk factors for MetSX8Walnut56 g/dayNo nutsAd libitum, participants advised to substitute walnuts for other foodsFMD (%)
Kurlansky and Stote,41 USA47 (F)Almond: 41.8±11.7
Almond+chocolate: 46.2±7.8 Chocolate: 36.5±11.9
C: 51.3±6.3
Almond: 25.3±3.5
Almond+chocolate: 27.2±4.2
Chocolate: 23.9±3.3
C: 26.1±4.1
Healthy, including HCP6Almond1. 60 g/day
2. 60 g almonds/day + 41 g dark chocolate/day
1. 41 g dark chocolate/day
2. Self-selected diet
Therapeutic Lifestyle Change diet (isocaloric)CRP (mg/L), ICAM-1 (ng/mL), VCAM-1 (ng/mL)
Lee et al,15 South Korea60 (M, F)††Ages 35–65 eligible for studyI: 27.19±2.11
C: 26.96±2.16
MetSP6Mixed nuts (walnut, pine nut, peanut)30 g mixed nuts/day (15 g walnuts, 7.5 g pine nuts, 7.5 g peanuts)Prudent dietPrudent diet (isocaloric)CRP (mg/L), adiponectin (μg/mL), IL-6 (pg/mL), ICAM-1 (ng/mL), VCAM-1 (ng/mL)
Liu et al,21 China20 (M: 9, F: 11)58±226.0±0.7T2DM and HLX4Almond56 g/day§§ (20% energy)NCEP step 2 dietNCEP Step II diet (isocaloric diet)CRP (mg/L), TNF-α (ng/L)‡, IL-6 (ng/L)‡, ICAM-1 (μg/L)‡, VCAM-1 (μg/L)‡
Ma et al,22 USA24 (M: 10, F: 14)58.1±9.232.5±5.0T2DMX8Walnut56 g/dayNo nutsAd libitum, participants advised to substitute walnuts for other foodsFMD (%)
Moreira Alves et al,42 Brazil65 (M)High oleic peanuts: 27.2±6.1
Peanuts: 27.6±1.5
C: 27.1±1.6
29.8±2.3OverweightP4Peanut (high oleic and conventional)1. 56 g/day high oleic peanuts
2. 56 g/day conventional peanuts
No peanutsHypocaloric diet (250 kcal/day deficit)CRP (mg/L)‡, TNF-α (pg/mL)
Mukuddem-Petersen et al,35 South Africa64 (M: 29, F: 35)45±10Walnut: 36 (95% CI 33.3 to 38.7)
Cashew: 34.4 (95% CI 32.3 to 36.6)
C: 35.1 (95% CI 32.8 to 37.4)
MetSP81. Walnut
2. Cashew
1. 20% energy from walnuts
2. 20% energy from cashews§
No nutsControlled feeding protocol (isocaloric)CRP (mg/L)
Njike et al,61 USA112 (M: 31, F: 81)Ad libitum: 56.5±11.7
Energy adjusted: 53.3±11.1
Ad libitum: 30.0±4.0: Energy adjusted: 30.2±4.1Overweight, prediabetic or MetSX***24Walnut56 g/dayNo nuts1. Ad libitum diet
2. Isocaloric diet (energy adjusted for walnuts)
FMD (%)
Parham et al,57 Iran44 (M: 11, F: 33)Intervention first: 53±10
Control first: 50±11
Intervention first: 32.16±6.58
Control first: 30.24±4.03
T2DMX12Pistachio50 g/dayNo pistachiosAd libitumCRP (mg/dL)‡
PREDIMED (Casas et al,43 Casas et al,44 Lasa et al,45 Urpi-Sarda et al,46 Spain353 (M: 172, F: 181)‡†††
124 (M: 45, F: 79)‡‡‡
110 (M: 55, F: 55)§§§
108 (M: 54, F: 54)¶¶¶
Range: 55–80 (M), 60–80 (F)29.4±3.4†††T2DM and/or CHD risk factorsP52 †††,‡‡‡,§§§
260 (5 years)¶¶¶
Mixed nuts (walnut, almond, hazelnut)30 g/day (15 g walnuts, 7.5 g hazelnuts, 7.5 g almonds)1 L olive oil per week****Mediterranean dietCRP (mg/L)††††,adiponectin(µg/mL),TNF-α(pg/mL),IL-6 (pg/mL),ICAM-1(µg/L)†
Rajaram et al,58 USA25 (M: 14, F: 11)41 (SEM: 13)71 (SEM: 2.7)‡‡Healthy (including overweight) to HCX4Almond1. 10% energy
2. 20% energy§
No nutsCholesterol lowering diet (isocaloric)CRP (mg/L), IL-6 (ng/L)‡
Rock et al,50 USA126 (F)50 (range: 22–72)¶¶33.5 (range: 22–40)¶¶OverweightP52Walnut42 g/day††(18% energy)Higher fat (35% energy) lower CHO (45% energy) diet, no nuts*Hypocaloric diet (500–1000 kcal/day deficit)CRP (μg/mL)‡, IL-6 (pg/mL)
Ros et al,18 Spain20 (M: 8, F: 12)55 (range: 26–75)70.6±10.3‡‡HCX4Walnut40–65 g/day (~18% energy) §No nutscholesterol lowering Mediterranean diet (isocaloric)CRP(mg/L)***,ICAM-1(µg/L)†,VCAM-1(µg/L)‡‡‡,FMD (%
Sauder et al,14 USA30 (M: 15, F: 15)56.1±7.831.2±3.1T2DMX4Pistachio20% total energy§Therapeutic lifestyle changes dietTherapeutic Lifestyle Changes diet (isocaloric)CRP (mg/L), ICAM-1 (ng/mL), VCAM-1 (ng/mL), FMD (%)
Sola et al,47 Spain56 (M: 23, F: 33)I: 56.79±10.46
C: 49.79±9.53
I: 27.30±3.01
C: 28.31±3.25
Pre-HT or HT with at least one risk factor for CVDP4Hazelnut30 g/day (in cocoa cream product)Cocoa cream product*Low saturated fat diet (isocaloric)CRP (mg/L), IL-6 (pg/mL), ICAM-1 (ng/mL), VCAM-1 (ng/mL)
Sweazea et al,48USA21 (M: 9, F: 12)I: 57.8±5.6 C: 54.7±8.9I: 37.2±7.8 C: 33.5±8.8T2DMP12Almond43 g (5–7x week) <2 servings non-trial nuts/weekHabitual dietCRP (mg/L), TNF-α (pg/mL), IL-6 (pg/mL)
Tey et al,13 New Zealand107 (M: 46, F: 61)42.5±12.430.6±5.1OverweightP12Hazelnut1. 30 g/day
2. 60 g/day
No nutsHabitual dietCRP (mg/L), IL-6 (pg/mL), ICAM-1 (μg/L)‡, VCAM-1 (μg/L)‡
West et al,59 USA28 (M: 10, F: 18)48 (SEM: 1.5)26.8 (SEM: 0.7)HLX4Pistachio1. 10% energy
2. 20% energy§
NCEP Step 1 dietIsocaloric dietFMD (%)
Wu et al,60 Germany40 (M: 10, F: 30)60±124.9±0.6Healthy (including overweight)X8Walnut43 g/dayNo nutsWestern diet with walnuts substituted for saturated fat (isocaloric)CRP(mg/dL)†,adiponectin(µg/mL)‡, ICAM-1(ng/mL),VCAM-1 (ng/mL)
  • *Study included other intervention group which was not relevant to this review, therefore this group was not included in this analysis. 

  • †Unit reported in study, converted to consistent unit for analysis.

  • ‡Units confirmed with study authors.

  • §Gram weight for dose sub-analysis based on mid-point of range of doses used.

  • ¶Gender breakdown estimated from % males reported in paper.

  • **Dose based on reference individual listed in Gulati et al.19

  • ††Gender breakdown for analysed participants not available.

  • ‡‡ Body weight (kg) is reported when BMI was not available.

  • §§Mean intake.

  • ¶¶Characteristics reported for randomised participants.

  • ***Participants were randomised to one of two parallel groups (ad libitum or calorie adjusted). Within each group participants completed a ‘walnut included’ and ‘walnut excluded’ period in a cross-over design.

  • †††ICAM.46

  • ‡‡‡Adiponectin.45

  • §§§VCAM-1.43

  • ¶¶¶CRP, IL-6, TNF-α.44

  • ****Treated as a comparison group for this analysis.

  • †††† Units based on primary publication.77

  • BMI, body mass index; CAD, coronary artery disease; CHD, coronary heart disease; CRP, C-reactive protein; CVD, cardiovascular disease; DL, dyslipidaemia; F, female; FMD, flow-mediated dilation; HC, hypercholesterolaemia; HL, hyperlipidaemia; HT, hypertension; ICAM-1, intercellular adhesion molecule 1; IL-6, interleukin 6; M, male; MetS, metabolic syndrome; NCEP, National Cholesterol Education Program; P, parallel; PREDIMED, PREvención con DIeta MEDiterránea; T2DM, type 2 diabetes mellitus; TNF-α, tumour necrosis factor; VCAM-1, vascular cell adhesion protein 1; X: cross-over.