REVIEW - Dietary interventions for RA

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Cochrane Database Syst Rev. 2009 Jan 21;(1):CD006400.

Dietary interventions for rheumatoid arthritis.

Hagen KB, Byfuglien MG, Falzon L, Olsen SU, Smedslund G.

National Resource Centre for Rehabilitation in Rheumatology,

Diakonhjemmet Hospital, PO Box 23 Vindern, 0319 Oslo, Norway.

BACKGROUND: The question of what potential benefits and harms are

associated with certain dietary regimes used in rheumatoid arthritis

is an important one for many patients and health care providers.

OBJECTIVES: To assess the effectiveness and safety of dietary

interventions in the treatment of rheumatoid arthritis.

SEARCH STRATEGY: We searched the Cochrane Central Register of

Controlled Trials (CENTRAL)(The Cochrane Library, issue 1 2008),

MEDLINE, EMBASE, AMED, CINAHL and reference lists of relevant articles

(up to January 2008), and contacted authors of included articles.

SELECTION CRITERIA: Randomised controlled trials (RCTs) or controlled

clinical trials (CCTs) where the effectiveness of dietary manipulation

was evaluated. Dietary supplement studies (including fish oil

supplements) were not included.

DATA COLLECTION AND ANALYSIS: Two authors independently selected

trials for inclusion, assessed the internal validity of included

trials and extracted data. Investigators were contacted to obtain

missing information.

MAIN RESULTS: Fourteen RCTs and one CCT, with a total of 837 patients,

were included. Due to heterogeneity of interventions and outcomes,

baseline imbalance and inadequate data reporting, no overall effects

were calculated. A single trial with a moderate risk of bias found

that fasting, followed by 13 months on a vegetarian diet, may reduce

pain (mean difference (MD) on a 0 to 10 scale -1.89, 95% confidence

interval (CI) -3.62 to -0.16), but not physical function or morning

stiffness immediately after intervention. Another single trial with a

moderate risk of bias found that a 12-week Cretan Mediterranean diet

may reduce pain (MD on a 0 to 100 scale -14.00, 95% CI -23.6 to

-4.37), but not physical function or morning stiffness immediately

after intervention. Two trials compared a 4-week elemental diet with

an ordinary diet and reported no significant differences in pain,

function or stiffness. Due to inadequate data reporting, the effects

of vegan and elimination diets are uncertain. When comparing any

dietary manipulation with an ordinary diet we found a significantly

higher total drop-out of 10% (risk difference (RD) 0.10, 95% CI 0.02

to 0.18), higher treatment-related drop-out of 5% (RD 0.05, 95% CI

-0.03 to 0.14) and a significantly higher weight loss (weighted mean

difference -3.23, 95% CI -4.79 to -1.67 kg) in the diet groups

compared to the control groups.

AUTHORS' CONCLUSIONS: The effects of dietary manipulation, including

vegetarian, Mediterranean, elemental and elimination diets, on

rheumatoid arthritis are still uncertain due to the included studies

being small, single trials with moderate to high risk of bias. Higher

drop-out rates and weight loss in the groups with dietary manipulation

indicate that potential adverse effects should not be ignored.

PMID: 19160281

http://www.ncbi.nlm.nih.gov/pubmed/19160281

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