Table 2.
Summary of study characteristics for included studies.
| Author (Year) | Country | Study Design | Participants’ Characteristics |
Intervention | Comparator | Duration | Primary Outcome Measures | Results (Post- Intervention Changes) | |
|---|---|---|---|---|---|---|---|---|---|
| Within Group | Between Groups | ||||||||
| Skoldstam et al. (1979) [30] | Sweden | RCT |
n = 26 Mean age: 53 yrs Sex: 73% f |
7–10 days fasting followed by 9-week lactovegetarian diet |
Habitual diet | 10 weeks | Pain, EMS, dose of NSAIDs | NSD | |
| Panush et al. (1983) [31] | US | RCT |
n = 33 Mean age: 55 yrs Sex: 34.6% f |
Diet free of additives, preservatives, fruit, red meat, herbs, and dairy products | Placebo diet | 10 weeks | EMS, number of tender and swollen joints, grip strength, patient and examiner assessment, walk time, ESR, RF, Hct/C3/C4 |
NSD | |
| Darlington et al. (1986) [32] | UK | RCT |
n = 45 Mean age: not reported Sex: 89% f |
Elimination diet Week 1: tolerated foods followed by reintroduction of foods that are unlikely to cause intolerance followed by habitual diet |
Habitual diet | 6 weeks | Pain, EMS, grip strength, number of painful joints |
NSD | Inadequate reporting |
| Magaro et al. (1988) [33] | Italy | RCT |
n = 12 Mean age: Group A: 37 yrs Group B: 36 yrs Sex: 100% f |
Group B: Diet high in PUFAs (P:S ratio 5:0) + fish oil supplement (1.6 g EPA/d and 1.1 g DHA/d) |
Group A: Diet high in saturated fatty acids (P:S ratio 1:33) |
4 weeks | DAS28, neutrophil chemiluminescence, Ritchie’s index, EMS, grip strength |
Significant improvements in Group B: Ritchie’s inde X(17.2 (3.38) to 10.6 (3.48)); (p < 001), EMS (33 (7.34) to 22 (8.45)) mins; (p < 001); Grip strength (116 (13–26) to 136 (12–88)) mmHg; (p < 001) |
Significant differences in: Ritchie’s index (Group B: 10.6 (3.48) vs. Group A: 21–4 (3.2); (p < 0.005) EMS (Group B: 22 (8.45) vs. Group A:36 (10.17) minutes; (p < 0.01) Grip strength (Group B:136 (12–88) vs. Group A: 104 (21–58) mmHg; (p < 0.01) |
| Kjeldsen-Kragh et al. (1991) [34] |
Norway | RCT |
n = 53 Mean age: 4.5 years Sex: 85% f |
7–10 days: fasting followed by 3·5 months: gluten-free vegan diet followed by 9 months: vegetarian diet |
Habitual diet | 13 months | Grip strength, Ritchie index, EMS, Global assessment, Number of tender and swollen joints, pain HAQ, ESR, CRP, white blood cells/platelet count | Significant improvements in the intervention group for: Grip strength (p < 0.0005), Ritchie Index (p < 0.0004), EMS (p < 0.0002); Number of tender joints (p < 0.0002), Number of swollen joints (p < 0.04), Pain (VAS) (p < 0.0001 for intervention group and p < 0.02 for control), HAQ (p < 0.0001), ESR (p < 0.002), CRP (p < 0.005) White blood cells/platelet count decreased significantly in the intervention group (p < 0.0010) and in the control group (p < 0.006) |
Significant improvement in the intervention group as compared with control for: Grip strength (p < 0.02), Ritchie index (p < 0.0004), EMS (p < 0.0001), Global assessment (p < 0.0001), Number of tender joints (p < 0.0001), Number of swollen joints (p < 0.02), pain (p < 0.02), HAQ (p < 0.0001), ESR (p < 0.001), CRP (p < 0.0001) |
| Van de Laar and van der Korst (1992) [35] |
Netherlands | RCT |
n = 94 Mean age: 58 yrs Sex: 70% f |
Allergen free diet |
Allergen restricted diet |
12 weeks | EMS, number of tender and swollen joints, Ritchie’s index, grip strength, global assessment, ESR, CRP, walking time | Significant decrease in body weight in the allergen free diet group (p = 0.016) | NSD |
| Haugen et al. (1994) [28] |
Norway | NRCT |
n = 17 Mean age: 50 yrs Sex: 80% f |
Elemental diet (E028) | Soup that included: milk, meat, fish, shellfish, orange, pineapples, tomatoes, peas and flour of wheat and corn | 3 weeks | Ritchie‘s index, number of tender and swollen joints, grip strength, EMS, pain, ESR, CRP, hemoglobin, albumin and erythrocyte count, global assessment |
Number of tender joints decreased significantly in the intervention group (p = 0.04) ESR and thrombocyte count improved in the control group (p = 0.03) and (p = 0.02), respectively |
NSD |
| Kavanagh et al. (1995) [36] |
UK | RCT |
n = 47 Mean age: 45.6 yrs Sex: 78.7% f |
E028 followed by reintroduction of food |
Habitual diet with E028 | 4 weeks | ESR, CRP, Ritchie’s index, thermographic score, grip strength, functional score | Significant improvements in the intervention group for: Ritchie’s index (12.6 ± 6.8 to 10.4 ± 7.2) (p = 0.006), Grip strength (140.2 ± 96 to 155.9 ± 98.3 mmHg) (p = 0.008) |
NSD |
| Hansen et al. (1996) [37] | Denmark | RCT |
n = 109 Mean age:57 yrs Sex: 74.6% f |
Graastener diet: 20–30% fat, 1.5 g/kg BW protein, 800 g fresh fish per week |
Habitual diet | 4 months | Number of tender and swollen joints, pain, HAQ, Global assessment, acute phase reactant, X-ray, EMS | Authors state: ‘Significant improvement in the duration of morning stiffness, number of swollen joints, pain status’ |
NSD |
| Nenonen et al. (1998) [38] |
Finland | RCT |
n = 43 Mean age:53 yrs Sex: 83% f |
Uncooked vegan diet |
Habitual diet | 3 months | Pain, number of swollen joints, number of tender joints, EMS, HAQ, Ritchie’s index, CRP, ESR | NSD |
|
| Holst-Jensen et al. (1998) [39] |
Denmark | RCT |
n = 30 Mean age: 49.5 yrs Sex: 80% f |
Commerical liquid elemental diet (top upTM Standard, Ferrosan Ltd., Denmark) | Habitual diet | 4 months | EMS, HAQ, number of swollen joints, pain, Ritchie’s index, global assessment, ESR | EMS decreased significantly in the control group (3.5 to 2.5 min) (p < 0.05) Ritchie’s inde Xdecreased significantly in the control group (12.5 to 10) (p < 0.05) |
Significant reductions in the intervention group as compared with control for: Number of tender joints (7 vs. 9) (p = 0.006), ESR (40 vs. 47 mm/h) (p = 0.018) |
| Fraser et al. (2000) [29] |
Norway | NRCT |
n = 23 Fasting group: Mean age: 49 yrs, Sex: 90% f Ketogenic group: Mean age:44 yrs, Sex: 92% f |
7-day ketogenic diet | 7-day fast | 1 week | IL-6, DHEAS | IL-6 decreased significantly after fasting for 7 days (35.5 to 22.5 pg/mL) (p < 0.05) DHEAS increased significantly after fasting for 7 days (3.28 to 4.40 mmol/L) (p < 0.01) and after a 7-day ketogenic diet group (2.42 to 3.23 mmol/L) (p < 0.01) |
Not reported |
| Sarzi-Puttini et al. (2000) [40] |
Italy | RCT |
n = 50 Mean age:50 yrs Sex: 78% f |
Diet free from: wheat meal, eggs, milk, strawberries and acid fruit, tomato, chocolate, crustacean, dried fruit Lean cuts of red meat allowed |
Diet containing common allergenic foods | 24 weeks | EMS, HAQ, number of tender and swollen joints, pain, Ritchie’s index | Number of tender and swollen joints decreased significantly in the intervention group (9.5 ± 4.1 to 7.1 ± 3.2) (p = 0.031) and (6.4 ± 3.1 to 5.1 ± 2.3) (p = 0.002), respectively Ritchie’s inde Xdecreased significantly in the intervention group (13.2 ± 4.4 to 9.2 ± 3.8) (p = 0.002) |
Not reported |
| Hafstrom et al. (2001) [41] |
Sweden | RCT |
n = 66 Mean age: 50 yrs Sex: not reported |
Gluten free vegan diet |
Well-balanced non-vegan diet | 12 months | IgG, IgA, radiographic progression | IgG anti-gliadin decreased significantly in the vegan diet group (5 to 2) (p = 0.0183) IgA anti-gliadin decreased significantly in the non-vegan diet group (14.5 to 12.5) (p = 0.0201) Modified Larsen score, number of erosions and the joint count improved significantly in both groups |
NSD |
| Skoldstam et al. (2003) [42] | Sweden | RCT |
n = 56 Mean age: 58.5 yrs Sex: = 82% f |
Cretan Mediterranean diet (MD) | Habitual diet (HD) | 12 weeks | DAS 28, HAQ, SF-36, dose of NSAIDs | DAS28 decreased significantly in MD group (4.4 to 3.9) (p < 0.001) HAQ decreased significantly in MD group (0.7 to 0.6) (p = 0.02) Improvement in vitality (+11.3) (p = 0.018) and overall health compared to one year earlier (−0.6) (p = 0.016) in the SF- 36 in MD group |
Significant improvements in MD group as compared to control group for: DAS28 (3.9 for MD vs. 4.3 for control) (p = 0.047) HAQ: (0.6 for MD vs. 0.8 for control) (p = 0.012) |
| Adam et al. (2003) [43] | Germany | RCT Double-blind crossover |
n = 68 Mean age: 57.4 ± 12.8 yrs Sex: 93.3% f |
Anti-inflammatory diet (AID) Patients in both diet groups were assigned to receive either placebo or fish oil capsules (30 mg/kg body weight) |
Western diet (WD) | 6 months | Global assessment, pain, grip strength, EMS, HAQ, Number of tender and swollen joints, blood cells, cytokines, eicosanoids, dose of Corticosteroids, CRP, LBT4, TNF-α | CRP decreased significantly for individuals in both WD and AID groups who are on methotrexate when fish oil was supplemented (2.03 ± 1.8 mg/dL vs. 1.69 ± 1.5 mg/dL) (p < 0.05) Number of tender joints improved significantly in AID group when fish oil was supplemented in months 5,6,7,8 (37% improvement) (p < 0.001) LTB4 decreased significantly in AID group when fish oil was supplemented for 3 months (p = 0.009) Dose of corticosteroid decreased significantly in both WD and AID groups after 3 months of fish oil supplementation (p = 0.027 for WD group, p = 0.022 for AID group) TNF-α decreased significantly in both WD and AID groups when fish oil was supplemented for months 6,7, 8 (p = 0.004) |
The number of tender and swollen improved significantly in the AID group as compared to WD group (28% vs. 11%) and (34% vs. 22%) (p < 0.01), respectively Patients’ and physicians’ global assessment of disease activity and patients’ assessments of pain improved significantly more in the AID group as compared to WD group (p < 0.05) |
| McKellar et al. (2007) [44] | Scotland | RCT |
n = 130 Mean age: 54 yrs Sex: 100% f |
Mediterranean diet (MD) |
Healthy diet | 5 months | Number of tender and swollen joints, patient global assessment, pain, EMS, DAS28, HAQ, ESR, CRP, IL-6 | Not reported |
Significant improvements in the intervention group as compared with the control group for: patient global assessment (p = 0.002), pain (p = 0.049) and EMS (p = 0.041) |
| Elkan et al. (2008) [45] |
Sweden | RCT |
n = 58 Vegan group: Mean age: 49.9 yrs, 93.3% f Non-vegan group Mean age:50.8 yrs, 85.6% f |
Gluten- free vegan diet | Well-balanced non-vegan diet | 12 months | oxLDL, anti-PCs | OxLDL decreased Significantly in the vegan diet group (54.7 to 48.6) (p = 0.09) |
Anti-PC IgM was significantly higher in vegan group (F = 8.0, p = 0.0006) |
| Vadell et al. (2020) [46] |
Sweden | RCT |
n = 50 Mean age: 61 ± 12 yrs Sex: 77% f |
Diet rich in anti-inflammatory foods |
Habitual diet | 10 weeks | DAS28-ESR | DAS28-ESR decreased significantly in the intervention group (3.39 to 3.05) (p = 0.012) |
NSD |
| Lederer et al. (2020) [47] | Germany | RCT |
n = 53 Mean age: 31 yrs Sex: 63% f |
Vegan diet (VD) | Meat rich diet | 5 weeks | Sialylated antibodies, percentage of regulatory T-cells, IL-10 |
Significant improvement in: Sialylated antibodies in VD (0.8 ± 0.4 to 1.4 ± 1.4) (p = 0.023) and in the meat rich group (0.9 ± 0.5 to 1.6 ± 1.2) (p = 0.010) T-cells in VD group (6.0 ± 1.7% to 7.1 ± 1.9%) (p < 0.001) and in meat rich group (6.3 ± 2.2% to 7.7 ± 2.4%) (p < 0.001) |
NSD |
Abbreviations: VAS: Visual Analogue Scale; EMS: Duration of early morning stiffness; NSAIDs: Non-steroidal anti-inflammatory drugs; RF: Rhheumatoid factor; Hct: Hematocrit; C3: Complement component 3; C4: Complement component 4; PUFA: Polyunsaturated fatty acids; EPA: Eicosapentaenoic acid; DHA: Docosahexaenoic acid; DAS28: Disease activity score in 28 joints; HAQ: Health assessment questionnaire; CRP: C-reactive protein; ESR: Erythrocyte sedimentation rate; IL-6:Interleukin-6; IL-10: Interleukin-10; DHEAS: Dehydroepiandrosterone sulfate; SF-36: Short form health survey; TNF- α: Tumor necrosis factor alpha; oxLDL: Oxidized low-density lipoprotein; anti-PCs: Immunoglobulin M antibodies against phosphorylcholine; BMI: Body mass index; BW: Body weight; f: females; yrs: years; mins: minutes; NSD: No significant difference.