TABLE 1.
Summary of study characteristics and outcomes of included randomized controlled trials investigating the effects of dietary patterns and biomarkers of immune inflammation
| Study, year (reference) | Participants, n | Sex (% female) | Age, 1 y | BMI, 1 kg/m2 | Study design, duration | Study population, country | Diet intervention | Control | Biomarkers measured with results2 | Application of intervention |
|---|---|---|---|---|---|---|---|---|---|---|
| Baguley, 2020 (30) | 23 | 0% | 65.9 ± 7.8 | 28.9 ± 3.4 | Parallel, 12 wk | Adults with prostate cancer, Australia | Mediterranean diet | Habitual diet | IL-6—, IL-8— | Personalized nutrition consultations every 2 wk |
| Jaacks, 2018 (35) | 30 | 73.3% | 51.6 ± 6.6 | 34 | Parallel, 8 wk | Adults consuming >10% of total daily calories in saturated and trans fats and total cholesterol intake of >300 mg/d, USA | Mediterranean diet | Habitual diet | CRP—, IL-6—, IL-8—, adiponectin— | 3 meals with beverages and 2 snacks per day provided; verbal and written dietary instructions throughout the study |
| Rallidis, 2017 (39) | 82 | 47.6% | 50.4 ± 7.3 | 32.2 ± 4.3 | Parallel, 2 mo | Adults with abdominal obesity without CVD or diabetes, Greece | Mediterranean diet | Habitual diet | CRP—, IL-6—, sICAM-1—, sVCAM-1—, sE-selectin— | Weekly phone calls and appointments with a dietitian |
| Davis, 2017 (40) | 152 | 55.9% | 70.9 ± 4.8 | 27.0 ± 3.9 | Parallel, 24 wk | Healthy older adults, Australia | Mediterranean diet | Habitual diet | hs-CRP—, F2-Isoprostanes ↓ | Participants attended the clinic every 2 wk to meet with a dietitian to ensure high adherence to the dietary protocol |
| Dyer, 2017 (41) | 99 | 88.8% | 63.0 ± 11.8 | 71.0 ± 15.4 | Parallel, 16 wk | Older adults with osteoarthritis, United Kingdom | Mediterranean diet | Habitual diet | IL-1α ↓, sCOMP—, IL-1β—, IL-2—, IL-4—, IL-6—, IL-8—, IL-10—, IFN-γ—, TNF-α—, VEGF—, EGF—, IL-6sR—, IL-2sR—, TNF-sR1—, TNF-sR2—, MCP-1—, MMP-9— | Nutritional information and dietary advice were provided. Dietitian was available for support via phone calls |
| Wade, 2019 (31) | 33 | 69.7% | 61 ± 7.1 | 30.6 ± 5.1 | Crossover, 8 wk | Adults with CVD risk factors, Australia | Mediterranean diet with extra pork | Low-fat diet | CRP— | Dietary resources and dietary counseling sessions every 2 wk |
| Mayr, 2018 (33) | 56 | 16.1% | 62.3 ± 8.8 | 29.9 ± 5.2 | Parallel, 6 mo | Adults with CHD, Australia | Mediterranean diet | Low-fat diet | hs-CRP—, hs-IL-6— | 2-wk model meal plan and resource kits provided. Counseling with dietitian at baseline, and after 3 and 6 mo. Additional short phone interviews at weeks 3, 6, and 9 and months 4 and 5 |
| Wade, 2018 (36) | 41 | 68.3% | 60.2 ± 6.9 | 30.8 ± 3.8 | Crossover, 8 wk | Adults with CVD risk factors, Australia | Mediterranean diet with extra dairy | Low-fat diet | CRP— | Dietary resources and dietary counseling sessions every 2 wk |
| Dus-Zuchowska, 2018 (37) | 144 | 100% | 60.6 ± 4.7 | 33.7 ± 4.9 | Parallel, 16 wk | Postmenopausal women with central obesity, Poland | Mediterranean diet | Low-fat diet | hs-CRP— | Main meals provided; other meals prepared by participants |
| Medina-Remon, 2017 (38) | 1139 | 55.1% | 67.6 ± 5.9 | 29.3 ± 3.4 | Parallel, 12 mo | Community-dwelling adults, Spain | Mediterranean diet with extra virgin olive oil, Mediterranean diet with extra nuts | Low-fat diet | In both diets: IL‐6 ↓, TNF‐α ↓, MCP‐1 ↓, VCAM‐1 ↓, ICAM‐1 ↓ | Personalized nutrition consultation at the baseline, advises every 3 mo, and group educational sessions every 3 mo |
| Casas, 2017 (42) | 44 | 56.8% | 66.9 ± 6.1 | 29.1 ± 3.7 | Parallel, 5 y | Older adults at high risk for CVD, Spain | Mediterranean diet with extra-virgin olive oil | Low-fat diet | IL-1β ↓, IL-5 ↓, IL-6—, IL-7 ↓, IL-8 ↓, IL-10—, IL-12p70—, IL-13 ↑, IL-18 ↓, TNF-α ↓, MCP-1 ↓, RANTES/CCL5 ↓, MIP-1β/CCL4 ↓, IP-10/CXCL10—, IFN-γ ↓, GCSF ↓, GMCSF—, E-selectin—, P-selectin—, sVCAM-1— | Individual sessions annually with dietitian, individual sessions every 3 mo, and group educational sessions every 3 mo |
| Casas, 2016 (46) | 106 | 54.3% | 66.5 ± 6.1 | 29.3 ± 3.9 | Parallel, 5 y | Older adults at high risk for CVD, Spain | Mediterranean diet with extra-virgin olive oil | Low-fat diet | hs-CRP ↓, IL-6 ↓, TNF-α ↓, MCP-1 ↓ | Individual sessions annually with dietitian, individual sessions every 3 mo, and group educational sessions every 3 mo |
| Maiorino, 2016 (44) | 215 | 50.7% | 52.2 ± 10.9 | 29.6 ± 3.5 | Parallel, 1 y | Adults with type 2 diabetes, Italy | Mediterranean diet | Low-fat diet | CRP ↓, adiponectin ↑, HMW adiponectin ↑, non-HMW adiponectin ↑ | Participants had dietary advice sessions every mo |
| Gomez-Delgado, 2015 (47) | 897 | NA | 59.5 ± 8.9 | 31.2 ± 4.5 | Parallel, 1 y | Adults with CHD, Spain | Mediterranean diet | Low-fat diet | CRP3 | Individual sessions with dietitian at baseline and every 6 mo |
| Chmurzynska, 2019 (32) | 95 | 100% | 60 ± 0.5 | 33.0 ± 4.4 | Parallel, 16 mo | Postmenopausal women with central obesity, Poland | Mediterranean diet | Central European diet | TNF-α—, IL-6— | Main meals were provided, other meals prepared by themselves |
| Monfort-Pires, 2017 (43) | 80 | 66.3% | 51.7 ± 9.3 | 30.5 ± 4.2 | Crossover, 4 wk | Adults with CVD risk factor, Brazil | Mediterranean modified type breakfast | Brazilian breakfast | CRP ↓, TNF-α ↓, IL-1β ↓, IL-6 ↓, IL-8 ↓, IFN-γ ↓, E-selectin ↓ | Participants received weekly calls and were instructed to maintain their normal diet, with exception to breakfast foods that were provided for consumption |
| Makarewicz-Wujec, 2020 (28) | 81 | 38.3% | 59.6 ± 7.9 | 29.2 ± 3.6 | Parallel, 6 mo | Patients with coronary artery disease, Poland | DASH diet | Habitual diet | hs-CRP—, CXCL4 ↓ | 6 dietary counseling sessions within 6 mo |
| Razavi-Zade, 2016 (45) | 60 | 50% | 41.3 ± 9.2 | 28.4 ± 3.2 | Parallel, 8 wk | Adults with overweight or obesity and NAFLD, Iran | DASH diet with calorie restriction | Traditional Iranian diet | hs-CRP ↓ | Participants received 7‐d cycle menus, dietary instructions, and a 45-min session with a dietitian |
| Asemi, 2015 (48) | 48 | 100% | 30.1 ± 6.4 | 30.3 ± 4.7 | Parallel, 8 wk | Overweight women with polycystic overage syndrome, Iran | DASH diet | Traditional Iranian diet | hs-CRP ↓ | Personalized dietary advice, and 7-d menu cycle |
| Juraschek, 2020 (29) | 217 | 47.9% | 45.2 ± 0.6 | 28.1 ± 0.2 | Parallel, 8 wk | Adults without CVD, diabetes, morbid obesity, or binge drinkers, USA | DASH diet, vegetarian diet | Typical American diet | DASH diet:hs-CRP—, hs-cTnl ↓vegetarian diet:hs-CRP—, hs-cTnl ↓ | 21 meals provided per week |
| Shah, 2018 (34) | 100 | 15.0% | 60 ± 10.0 | 30.3 ± 5.7 | Parallel, 8 wk | Adults with history of CAD, USA | Vegan diet | American Heart Association diet | hs-CRP ↓ | Personalized nutrition consultations every 4 wk and contact with dietitian per telephone and e‐mail. Weekly groceries and a cookbook were provided |
| Fritzen, 2015 (49) | 64 | 67.2% | 44.7 ± 4.4 | 30.9 ± 1.3 | Parallel, 26 wk | Healthy adults, Denmark | New Nordic Diet | Average Danish diet | CRP—, TNF-α—, adiponectin— | All foods and beverages were provided |
| Adamsson, 2015 (50) | 79 | 61.5% | 54.64 ± 8.4 | 28.3 ± 2.5 | Parallel, 12 wk | Healthy overweight adults, Sweden | Nordic prudent breakfast | Usual breakfast | CRP ↓, TNF-R2 ↓ | All breakfast foods were provided |
1
Values presented as mean ± SD
2
Differences of changes in biomarkers between intervention compared with control: ↑, significant increase of biomarker in intervention compared with control (P <0.05); ↓, significant decrease of biomarker in intervention compared with control (P <0.05); —, nonsignificant difference of biomarker between intervention compared with control (P ≥0.05).
3
Between group differences not available among all participants.
CAD, coronary artery disease; CHD, coronary heart disease; CRP, C-reactive protein; CXCL4, platelet factor-4; DASH, Dietary Approaches to Stop Hypertension; EGF, epidermal growth factor; GMCSF, granulocyte-macrophage colony-stimulating factor; GCSF, granulocyte colony-stimulating factor; HMW, high-molecular weight; hs, high sensitivity; hs-cTnl, high-sensitivity troponin l; ICAM‐1, intercellular adhesion molecule 1; IP-10/CXCL10, interferon γ-induced protein 10/C-X-C motif chemokine ligand 10; MCP-1, monocyte chemoattractant protein 1; MMP-9, matrix metallopeptidase 9; MIP-1β/CCL4, macrophage inflammatory protein-1 β/C-C motif chemokine ligand 4; NA, not available; NAFLD, non-alcoholic fatty liver disease; RANTES/CCL5, regulated upon activation, normal T cell expressed and secreted/chemokine ligand 5; sCOMP, serum cartilage oligomeric matrix protein; sVCAM-1, soluble vascular cell adhesion molecule-1; TNF-R2, TNF receptor-2; VEGF, vascular endothelial growth factor.