Dietary manipulation in musculoskeletal conditions.

Dietary advice and intervention clearly have a place in rheumatology and allow patients to have some control over their own disease. Although there is no evidence for efficacy of 'fad' diets, 30-40% of rheumatoid patients can benefit from excluding foods individually identified during the reintroduction phase of an elimination diet. A proportion of patients who follow a vegetarian or Mediterranean-type diet will experience benefit. Patients who are either overweight or obese should participate in weight-loss programmes. Those with osteoarthritis need to concentrate on reducing fat mass while maintaining muscle mass. Arthritic patients, other than those with gout, should increase their intake of oily fish and additionally supplement with fish oil for up to 3 months to see whether they experience benefit. All arthritic patients, particularly those with inflammatory disease, should be advised to ensure a good dietary intake of antioxidants, copper and zinc. Supplementation with selenium and vitamin D may be advisable.

Dietary antioxidants in inflammatory arthritis: do they have any role in etiology or therapy?

Rheumatoid arthritis is an autoimmune-mediated inflammatory disease of unknown etiology, and is characterized by joint pain and soft-tissue swelling. The role of dietary antioxidants in the prevention and amelioration of symptoms in inflammatory joint disease has been of interest for many years. Epidemiological studies provide evidence of a link between dietary antioxidant intake and the likelihood of developing inflammatory arthritis. Interventional studies of antioxidant supplementation in established disease have been inconclusive overall; however, the quality of such studies has often been poor. The pathways by which antioxidant compounds might act are now better understood. In this Review, we explore not only some of the accepted mechanisms of antioxidant function but also outline some concepts that could aid further investigation of the potential therapeutic role of dietary antioxidants in inflammatory arthritis.

Dietary beta-cryptoxanthin and inflammatory polyarthritis: results from a population-based prospective study.

BACKGROUND: Epidemiologic studies suggest that the antioxidant potential of dietary carotenoids may protect against the oxidative damage that can result in inflammation. OBJECTIVE: We investigated the hypothesis that some dietary carotenoids are associated with a reduced risk of developing inflammatory polyarthritis (IP). DESIGN: The European Prospective Investigation of Cancer Incidence (EPIC)-Norfolk study is a population-based, prospective study of >25,000 subjects who completed a baseline 7-d diet diary and were followed up to identify new cases of IP, which was defined as synovitis that affected > or = 2 joint groups. Dietary carotenoid intakes were computed from the diet diaries of these subjects, and a nested, case-control analysis was undertaken to compare carotenoid intake between case subjects and age- and sex-matched control subjects. RESULTS: Eighty-eight incident cases of IP that occurred in the population surveyed were ascertained via the Norfolk Arthritis Register. The mean daily intakes of zeaxanthin and beta-cryptoxanthin were 20% and 40% lower, respectively, in the cases than in the 176 controls, but there were no significant differences in the intakes of either lutein or lycopene. Those subjects in the top one-third of intake of zeaxanthin and beta-cryptoxanthin were at a lower risk of developing IP than were subjects in the lowest one-third [odds ratios (95% CI): 0.48 (0.24, 0.94) and 0.51 (0.25, 1.02) for zeaxanthin and beta-cryptoxanthin, respectively]. The association with beta-cryptoxanthin was significant after adjustments were made for total energy and protein intakes and for cigarette smoking. CONCLUSION: These data are consistent with previous evidence showing that a modest increase in beta-cryptoxanthin intake, equivalent to one glass of freshly squeezed orange juice per day, is associated with a reduced risk of developing inflammatory disorders such as rheumatoid arthritis.

Who and how many people are taking herbal supplements? A survey of 21,923 adults.

BACKGROUND: There is little information on the number and characteristics of adults taking herbal supplements and the relationship of this with other health and lifestyle factors. These were examined in the current study. METHODS: Information on herbal supplement use and health and lifestyle characteristics was obtained by postal questionnaire, sent to a sample of the adult population in Northwest England. RESULTS: In summer 2001, 70.5% (15,465/21,923) of questionnaires were returned. The mean age of responders was 49.8 years (SD 17.57) and 45.2% (6,986/15,465) were men. The percentage taking at least one herbal supplement was 12.8% (1,987/15,465). Users of herbal supplements were more likely to be younger, female, white, and to own their home. Herbal supplement use was not strongly associated with any health and lifestyle variables examined. Weak associations were found with physical activity, psychiatric caseness, and use of prescribed medications. The most common herbal supplement was evening primrose oil, taken by 7.7% (1,186/15,465) of respondents (12.7% of women and 1.1% of men). CONCLUSIONS: More than one in ten adults were taking herbal supplements, with evening primrose oil, the most common supplement, used mainly by women. Individual characteristics such as age, sex, ethnicity, and social class influenced the use of herbal supplements, but there was no evidence that this substituted for conventional medical care. The evidence base to support some popular herbal supplements is weak. Large well-designed trials are needed to quantify the value of herbal supplements to health and well-being.

Does diet have a role in the aetiology of rheumatoid arthritis?

Although dietary factors have been extensively studied in many chronic diseases, the role of diet in the epidemiology of rheumatoid arthritis (RA) has received little attention. Fruit and vegetables and dietary antioxidants are thought to play a protective role in the pathogenesis of CVD and some cancers, but few studies have investigated these dietary components in the aetiology of RA. Fish oil supplementation has consistently been shown to have a beneficial effect on the symptoms of established RA, but it is not known whether the PUFA present in fish oils can reduce the risk of developing the disease. There is evidence that RA is less severe in the southern Mediterranean countries, such as Italy and Greece, where oil-rich fish, fruit, vegetables and olive oil are consumed in greater amounts than in many other countries. Overall, the evidence for a role of diet in the aetiology of RA is limited to a small number of observational studies of very different designs. Recently, it was demonstrated that lower intakes of fruit and vegetables and dietary vitamin C are associated with an increased risk of developing inflammatory polyarthritis in a free-living population in Norfolk, UK. These findings provide further evidence for a role of diet in the development of inflammatory arthritis, although the mechanisms involved are uncertain.

The role of diet in susceptibility to rheumatoid arthritis: a systematic review.

OBJECTIVE: Many studies have examined the role of diet in the management of established rheumatoid arthritis (RA), warranting several recent reviews. However, none have considered the possible link between diet and the onset of RA in detail. Studies investigated a possible effect of individual components of diet and the development of RA, but the lack of a systematic review means there is no unbiased assessment of the evidence. METHODS: We systematically reviewed studies with comparison groups that examined dietary intake or biological markers prior to the onset of RA. Four electronic databases were searched to identify relevant reports. Six quality criteria were agreed, against which the studies were assessed. The main outcome measure was a diagnosis of RA according to the ARA 1958 or revised ACR 1987 classification criteria. RESULTS: Fourteen reports were included in the review. There was evidence of a protective effect of higher consumption of olive oil, oil-rich fish, fruit, vegetables and beta-cryptoxanthin. Lower serum concentrations of antioxidants were associated with an increased risk of RA in 3 studies. Due to the heterogeneity of study designs and analyses, the results could not be pooled. CONCLUSION: Evidence exists that diet may play a role in the etiology of RA, but it is inconclusive due to the small number of studies available and variation in study design.

Dietary risk factors for the development of inflammatory polyarthritis: evidence for a role of high level of red meat consumption.

OBJECTIVE: To investigate the association of red meat and other specific dietary components in predicting the development of inflammatory polyarthritis. METHODS: This nested case-control study was conducted within a prospective population-based study of cancer incidence (European Prospective Investigation of Cancer in Norfolk [EPIC-Norfolk]). EPIC-Norfolk recruited 25,630 subjects ages 45-75 years between 1993 and 1997. Dietary intake was assessed at baseline using a 7-day food diary, and the information was analyzed using dietary analysis software. Patients with new cases of inflammatory polyarthritis were identified by linkage with the Norfolk Arthritis Register, a primary care-based inception study of inflammatory polyarthritis, and were matched for age and sex to 2 controls from EPIC-Norfolk. The risk for development of inflammatory polyarthritis was compared between subjects in the highest and lowest tertiles of dietary intake using conditional logistic regression and was expressed as odds ratios (ORs) with 95% confidence intervals (95% CIs). RESULTS: Between 1993 and 2002, 88 new patients with inflammatory polyarthritis were identified and matched with 176 controls. Among patients, the level of red meat intake was higher (P = 0.04) and that of vitamin C was lower (P = 0.03) compared with intake among controls, but no difference in total energy intake was observed. Patients were more likely to be smokers. After adjusting for total energy intake, smoking, and other possible dietary confounders, subjects with the highest level of consumption of red meat (OR 1.9, 95% CI 0.9-4.0), meat and meat products combined (OR 2.3, 95% CI 1.1-4.9), and total protein (OR 2.9, 95% CI 1.1-7.5) were at an increased risk for inflammatory polyarthritis. CONCLUSION: A high level of red meat consumption may represent a novel risk factor for inflammatory arthritis or may act as a marker for a group of persons with an increased risk from other lifestyle causes.