Nutritional management of rheumatoid arthritis: a review of the evidence

Nutritional status of Iranian women with rheumatoid arthritis: an assessment of dietary intake and disease activity

BACKGROUND

Long-standing chronic diseases such as rheumatoid arthritis are known to be associated with impairment of nutritional status to some degree. The present study aimed to assess nutritional status of women with rheumatoid arthritis and compare their ingestion of certain micronutrients with dietary reference intakes.

METHODS

In this cross-sectional study, 90 eligible women were recruited. After examination, all patients were evaluated on the basis of disease activity score, calculated using the number of tender and swollen joints, patient global assessment of pain and high sensitivity C-reactive protein (CRP). A three-day 24 h recall was completed and a 10 ml fasting blood sample was obtained to assess the plasma levels of malondialdehyde, total antioxidant and CRP.

RESULTS

Despite normal BMI, intake of energy and micronutrients including calcium, folic acid, zinc, magnesium and vitamin B6 were considerably lower compared with the dietary reference intakes. There was no significant relationship between intake of different nutrients or food groups and disease activity score and the biochemical markers including malondialdehyde, CRP and total antioxidant.

CONCLUSIONS

Intake of energy and some micronutrients were significantly lower than the recommended values. However, no relationship was found between intake of different food groups or nutrients with disease activity or serum antioxidant capacity.

Effects of Glucosamine and Chondroitin Sulfate on Cartilage Metabolism in OA: Outlook on Other Nutrient Partners Especially Omega-3 Fatty Acids

Osteoarthritis (OA) is a degenerative joint disease that is characterized by increasing loss of cartilage, remodeling of the periarticular bone, and inflammation of the synovial membrane. Besides the common OA therapy with nonsteroidal anti-inflammatory drugs (NSAIDs), the treatment with chondroprotectives, such as glucosamine sulfate, chondroitin sulfate, hyaluronic acid, collagen hydrolysate, or nutrients, such as antioxidants and omega-3 fatty acids is a promising therapeutic approach. Numerous clinical studies have demonstrated that the targeted administration of selected micronutrients leads to a more effective reduction of OA symptoms, with less adverse events. Their chondroprotective action can be explained by a dual mechanism: (1) as basic components of cartilage and synovial fluid, they stimulate the anabolic process of the cartilage metabolism; (2) their anti-inflammatory action can delay many inflammation-induced catabolic processes in the cartilage. These two mechanisms are able to slow the progression of cartilage destruction and may help to regenerate the joint structure, leading to reduced pain and increased mobility of the affected joint.

Risk characterization for mercury, dichlorodiphenyltrichloroethane and polychlorinated biphenyls associated with fish consumption in Serbia

The aim of this work was to assess the risk due to mercury (Hg), dichlorodiphenyltrichloroethane (DDT) and non-dioxin-like polychlorinated biphenyls (ndl PCBs) intake via fish consumption in Serbia. We have developed 24 scenarios using four concentration levels (mean, maximum, 50th and 95th percentile) of contaminants, determined in 521 samples of fish products available on Serbian market; two consumption levels (Food and Agriculture Organization/World Health Organization data and recommendation of American Heart Association); and three body weights (5th, 50th and 95th percentile). All the values concerning the intake of DDT are below the corresponding health based guidance value. Calculated weekly intake of Hg using maximal concentration, intake of 340g/week and 5th percentile of body weight exceeded the provisional tolerable weekly intake (PTWI). When maximal and 95th percentile concentration of ndl PCBs was used, weekly intakes exceeded a "guidance value" with one exception i.e., when 95th percentile of concentration along with 95th percentile of body weight were used. Concerning Hg and ndl PCBs, when extreme concentrations were used, HIs exceeded the value of 1, indicating that fish and fishery products may pose a threat to consumer's health.

Rheumatoid cachexia and cardiovascular disease

Both cachexia and cardiovascular disease are strongly associated with rheumatoid arthritis (RA) and linked to the chronic inflammatory process. Typically, rheumatoid cachexia occurs in individuals with normal or increased BMI (reduced muscle mass and increased fat mass). Classic cachexia (reduced muscle mass and reduced fat mass) is rare in RA but is associated with high inflammatory activity and aggressive joint destruction in patients with a poor cardiovascular prognosis. Conversely, obesity is linked to hypertension and dyslipidemia but, paradoxically, lower RA disease activity and less cardiovascular disease-related mortality. Rheumatoid cachexia might represent the 'worst of both worlds' with respect to cardiovascular outcome, but until diagnostic criteria for this condition are agreed upon, its effect on cardiovascular disease risk remains controversial.

Energy regulation and neuroendocrine-immune control in chronic inflammatory diseases

Energy regulation (EnR) is most important for homoeostatic regulation of physiological processes. Neuroendocrine pathways are involved in EnR. We can separate factors that provide energy-rich fuels to stores [parasympathetic nervous system (PSNS), insulin, insulin-like growth factor-1, oestrogens, androgens and osteocalcin] and those that provide energy-rich substrates to consumers [sympathetic nervous system (SNS), hypothalamic-pituitary-adrenal axis, thyroid hormones, glucagon and growth hormone]. In chronic inflammatory diseases (CIDs), balanced energy-rich fuel allocation to stores and consumers, normally aligned with circadian rhythms, is largely disturbed due to the vast fuel consumption of an activated immune system (up to 2000 kJ day(-1)). Proinflammatory cytokines such as tumour necrosis factor or interleukins 1beta and 6, circulating activated immune cells and sensory nerve fibres signal immune activation to the rest of the body. This signal is an appeal for energy-rich fuels as regulators are switched on to supply energy-rich fuels ('energy appeal reaction'). During evolution, adequate EnR evolved to cope with nonlife-threatening diseases, not with CIDs (huge negative selection pressure and reduced reproduction). Thus, EnR is inadequate in CIDs leading to many abnormalities, including sickness behaviour, anorexia, hypovitaminosis D, cachexia, cachectic obesity, insulin resistance, hyperinsulinaemia, dyslipidaemia, fat deposits near inflamed tissue, hypoandrogenaemia, mild hypercortisolaemia, activation of the SNS (hypertension), CID-related anaemia and osteopenia. Many of these conditions can contribute to the metabolic syndrome. These signs and symptoms become comprehensible in the context of an exaggerated call for energy-rich fuels by the immune system. We propose that the presented pathophysiological framework may lead to new therapeutical approaches and to a better understanding of CID sequence.

Integrative medicine approach to chronic pain

Chronic pain can be a frustrating condition for patient and clinician. The integrative medicine approach to pain can offer hope, adding safe complementary and alternative medical (CAM) therapies to mitigate pain and suffering. Such CAM therapies include nutrition, supplements and herbs, manual medicine, acupuncture, yoga, and mind-body approaches. The evidence is heterogeneous regarding these approaches, but some evidence suggests efficacy and confirms safety. The integrative medicine approach can be beneficial in a patient with chronic pain.

Effectiveness and safety of dietary interventions for rheumatoid arthritis: a systematic review of randomized controlled trials

This systematic review assesses the effectiveness and safety of dietary interventions for rheumatoid arthritis. Randomized controlled trials comparing any dietary manipulation with an ordinary diet were included. Eight randomized controlled trials with a total of 366 patients were included. One trial found that fasting, followed by 13 months on a vegetarian eating plan, might reduce pain (mean difference on a zero to 10 scale -1.89, 95% confidence interval [CI] -3.62 to -0.16). Another single trial found that a 12-week Cretan Mediterranean eating plan might reduce pain (mean difference on a 0 to 100 scale -14.00, 95% CI -23.6 to -4.37). Due to inadequate data reporting, the effects of vegan eating plans and elimination diets are uncertain. When comparing any dietary manipulation with an ordinary diet we found a higher total drop-out of 8% (risk difference 0.08, 95% CI -0.01 to 0.17), higher treatment-related drop-out of 5% (risk difference 0.05, 95% CI -0.03 to 0.14) and a significantly higher weight loss (weighted mean difference -3.24, 95% CI -4.81 to -1.67 kg) in the diet groups compared to the control groups. The effects of dietary manipulation, including vegetarian, Mediterranean, and elemental eating plans, 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. We conclude that higher dropout rates and weight loss in the groups with dietary manipulation indicate that potential adverse effects should not be ignored.

Dietary fish and fish oil and the risk of rheumatoid arthritis

BACKGROUND

Intake of fish oil and oily fish has been reported to improve clinical symptoms in people who have rheumatoid arthritis. Whether the intake of oily fish and fish oil might also protect against the development of rheumatoid arthritis is not known.

OBJECTIVE

We investigated the association between intake of oily fish and fish oil supplements and the risk of rheumatoid arthritis in a population-based case-control study.

METHODS

The study comprised 1889 incident cases of rheumatoid arthritis and 2145 randomly selected controls recruited from a geographically defined area of Sweden during 1996-2005. Data on the consumption of oily fish and fish oil supplements 5 years preceding enrollment had been obtained through a questionnaire. We calculated odds ratios (ORs) for the development of rheumatoid arthritis, using logistic regression to adjust for age, residential area, body mass index, smoking, and alcohol consumption.

RESULTS

Compared with subjects who never or seldom consumed oily fish, the OR for developing rheumatoid arthritis was 0.8 (95% confidence interval = 0.6-1.0) for subjects who consumed oily fish 1-7 times a week. The results did not change notably when stratifying the cases for rheumatoid factor or for antibodies to citrullinated peptide antigens. Similar results were seen for subjects consuming oily fish 1-3 times a month. Cases and controls did not differ in their consumption of fish oil supplements.

CONCLUSION

Intake of oily fish was associated with a modestly decreased risk of developing rheumatoid arthritis.

Therapeutic potential of n-3 polyunsaturated fatty acids in disease

PURPOSE

The potential therapeutic benefits of supplementation with n-3 polyunsaturated fatty acids (PUFAs) in various diseases are reviewed, and the antiinflammatory actions, activity, and potential drug interactions and adverse effects of n-3 PUFAs are discussed.

SUMMARY

Fish oils are an excellent source of long-chain n-3 PUFAs, such as eicosapentaenoic acid and docosahexaenoic acid. After consumption, n-3 PUFAs can be incorporated into cell membranes and reduce the amount of arachidonic acid available for the synthesis of proinflammatory eicosanoids (e.g., prostaglandins, leukotrienes). Likewise, n-3 PUFAs can also reduce the production of inflammatory cytokines, such as tumor necrosis factor alpha, interleukin-1, and interleukin-6. Considerable research has been conducted to evaluate the potential therapeutic effects of fish oils in numerous conditions, including arthritis, coronary artery disease, inflammatory bowel disease, asthma, and sepsis, all of which have inflammation as a key component of their pathology. Additional investigations into the use of supplementation with fish oils in patients with neural injury, cancer, ocular diseases, and critical illness have recently been conducted. The most commonly reported adverse effects of fish oil supplements are a fishy aftertaste and gastrointestinal upset. When recommending an n-3 PUFA, clinicians should be aware of any possible adverse effect or drug interaction that, although not necessarily clinically significant, may occur, especially for patients who may be susceptible to increased bleeding (e.g., patients taking warfarin).

CONCLUSION

The n-3 PUFAs have been shown to be efficacious in treating and preventing various diseases. The wide variation in dosages and formulations used in studies makes it difficult to recommend dosages for specific treatment goals.

Effect of green tea extract and vitamin C on oxidant or antioxidant status of rheumatoid arthritis rat model

Elevated free radical generation in inflamed joints and impaired antioxidant system has been implicated in rheumatoid arthritis (RA). Green tea extracts (GTE) have been shown to reduce inflammation in inflammatory arthritis murine model. This study investigates possible mechanisms by which vitamin C and GTE protect joints in RA rat model. This study included forty adult male rats that were divided into four groups (10 rats each); control group, collagen II induced RA group (CII), CII treated with vitamin C (CII + Vit C) and CII treated with GTE (CII + GTE) in physiology laboratory, Assiut University, Egypt. After 45 days of treatment, plasma levels of lipid peroxides (LPO), nitric oxide (NO), ceruloplasmin (CP), superoxide dismutase (SOD), uric acid (UA) and glutathione (GSH) were detected using colorimetric methods, PGE(2) using ELISA and copper (Cu) and zinc (Zn) using spectrometer. In CII group, levels of LPO, NO, PGE(2), UA, CP, Cu were higher while SOD, GSH, Zn were lower than controls. In groups treated with vitamin C and GTE, levels of SOD, GSH were increased while levels of LPO, NO, PGE(2), Cu, CP were decreased compared with CII group. Levels of UA were decreased and Zn increased in GTE treated group compared with CII group. GTE treated group showed higher Zn and low Cu levels compared with vitamin C treated group. This study suggests proper GTE and vitamin C intake may effectively normalize the impaired oxidant/antioxidant system and delaying complication of RA.

Effect of glucosamine sulfate with or without omega-3 fatty acids in patients with osteoarthritis

INTRODUCTION

A total of 177 patients with moderate-to-severe hip or knee osteoarthritis (OA) were tested over a period of 26 weeks in a two-center, two-armed, randomized, double-blind, comparison study. The aim was to see if a combination of glucosamine sulfate (1500 mg/day) and the omega-3 polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (group A), showed equivalence (noninferiority) or superiority as opposed to glucosamine sulfate alone (group B).

METHODS

The primary therapy evaluation was performed using the Western Ontario and McMaster Universities Arthrosis index (WOMAC) score. At the end of the study, a reduction in the pain score of > or =20% was required (primary target criterion) and the quantitative difference in the WOMAC subscores pain, stiffness, and function were analyzed (secondary target criteria).

RESULTS AND CONCLUSION

When a minimal pain reduction of > or =20% was chosen, there was no statistically significant difference in the number of responders between the two groups (92.2% group A, 94.3% group B). A higher responder criterion (> or =80% reduction in the WOMAC pain score) was chosen. Therefore, the frequency of responders showed a therapeutic and statistical superiority for the combination product of glucosamine sulfate and the omega-3 polyunsaturated fatty acids in patients who complied with the study protocol (group A 44%, group B 32%; P=0.044). OA symptoms (morning stiffness, pain in hips and knees) were reduced at the end of the study: by 48.5%-55.6% in group A and by 41.7%-55.3% in group B. The reduction was greater in group A than in group B. There was a tendency toward superiority shown in the secondary target criteria and concurrent variables. In the global safety evaluation, both products have been demonstrated to be very safe in long-term treatment over 26 weeks. To our knowledge, this is the first clinical trial in which glucosamine was given in combination with omega-3 fatty acids to patients with OA.

Dietary interventions for rheumatoid arthritis

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.

Rheumatoid cachexia: a clinical perspective

Rheumatoid cachexia is under-recognized in clinical practice. The loss of lean body tissue, which characterizes cachexia, is often compensated for by gain in body fat-so called 'cachectic obesity'-so that 85% or more RA patients have a normal BMI. Severe cachexia with loss of weight leads to increased morbidity and premature mortality but loss of muscle bulk with a normal BMI also associates with poor clinical outcomes. Increasing BMI, even into the obese range, is associated with less joint damage and reduced mortality. Measurement of body composition using DXA and other techniques is feasible but the results must be interpreted with care. Newer techniques such as whole-body MRI will help define with more confidence the mass and distribution of fat and muscle and help elucidate the relationships between body composition and outcomes. Cachexia shows little response to diet alone but progressive resistance training and anti-TNF therapies show promise in tackling this potentially disabling extra-articular feature of RA.

Simulated impact of a fish based shift in the population n--3 fatty acids intake on exposure to dioxins and dioxin-like compounds

Due to the favourable health effects of LC n-3 PUFAs, marine products have been recognised as a food group of special importance in the human diet. However, seafood is susceptible to contamination by lipophilic organic pollutants. The objective of this study was to evaluate intake levels of PCDDs, PCDFs and dioxin-like PCBs, by a probabilistic Monte Carlo procedure, in relation to the recommendation on LC n-3 PUFAs given by Belgian Federal Health Council. Regarding the recommendation, two scenarios were developed differing in LC n-3 PUFAs intake: a 0.3 E% and a 0.46 E% scenario. Total exposure to dioxins and dioxin-like substances in the 0.3 E% LC n-3 PUFAs scenario ranges from 2.31 pg TEQ/kg bw/day at the 5th percentile, over 4.37 pg TEQ/kgbw/day at the 50th percentile to 8.41 pg TEQ/kgbw/day at the 95th percentile. In the 0.46 E% LC n-3 PUFAs scenario, 5, 50 and 95th percentile are exposed to 2.74, 5.52 and 9.98 pg TEQ/kgbw/day, respectively. Therefore, if the recommended LC n-3 PUFAs intake would be based on fish consumption as the only extra source, the majority of the study population would exceed the proposed health based guidance values for dioxins and dioxin-like substances.

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.

Projected prevalence of US adults with self-reported doctor-diagnosed arthritis, 2005 to 2050

Using population-based survey data from the 2003 Behavioral Risk Factor Surveillance Survey (BRFSS), we estimated the population prevalence of self-reported, doctor-diagnosed arthritis in the US from 2005 to 2050. Projected arthritis-prevalence data were estimated in 5-year increments along sex- and age-specific categories by multiplying the 2003 BRFSS arthritis prevalence data by the sex-stratified US Census projections. During this 45-year period, we estimate that the total number of US adults aged 20 years or older with arthritis will increase from 60 million to 96 million, a 1.6-fold increase. The increase is projected to be greater in those aged 65 years or older (a 2.3-fold increase) than for those aged 20 to 65 (a 1.3-fold increase). Given increases in the prevalence of known arthritis risk factors (e.g., obesity, Hispanic origin) our projections might underestimate the prevalence of arthritis in the coming years.

Pathogenesis of degenerative temporomandibular joint arthritides

Over the past decade, remarkable progress has been made in the study of molecular mechanisms involved in degenerative temporomandibular joint arthritides. Based on recent findings, models of degenerative temporomandibular joint disease predict that mechanical loads trigger a cascade of molecular events leading to disease in susceptible individuals. These events involve the production or release of free radicals, cytokines, fatty acid catabolites, neuropeptides, and matrix-degrading enzymes. Under normal circumstances, these molecules may be involved in the remodeling of articular tissues in response to changing functional demands. However, if functional demands exceed the adaptive capacity of the temporomandibular joint or if the affected individual is susceptible to maladaptive responses, then a disease state will ensue. An individual's susceptibility to degenerative temporomandibular joint disease may be determined by several factors, including genetic backdrop, sex, age, and nutritional status. It is hoped that, by furthering our understanding of the molecular events that underlie degenerative temporomandibular joint diseases, improved diagnostics and effective therapies for these debilitating conditions will be developed.

Dietary treatment of rheumatoid cachexia with β-hydroxy-β-methylbutyrate, glutamine and arginine: A randomised controlled trial

BACKGROUND & AIMS

Rheumatoid arthritis (RA) is complicated by cytokine-driven alterations in protein and energy metabolism and consequent muscle wasting (cachexia). The aim of this randomised controlled trial was to investigate the efficacy of a mixture of beta-hydroxy-beta-methylbutyrate, glutamine and arginine (HMB/GLN/ARG) as nutritional treatment for rheumatoid cachexia.

METHODS

Forty RA patients supplemented their diet with either HMB/GLN/ARG or a nitrogen (7.19 g/day) and calorie (180 kcal/day) balanced mixture of alanine, glutamic acid, glycine, and serine (placebo) for 12 weeks. Body composition and other outcomes were assessed at baseline and follow-up, and analysed by mixed ANOVA.

RESULTS

Dietary supplementation with HMB/GLN/ARG was not superior to placebo in the treatment of rheumatoid cachexia (groupxtime interactions P>0.05 for all outcomes). Both amino acid mixtures significantly increased (main effect of time) fat-free mass (727+/-1186 g, P<0.01), total body protein (719+/-1703 g, P=0.02), arms (112+/-183 g, P<0.01) and legs (283+/-534 g, P<0.01) lean mass, and some measures of physical function. No significant adverse event occurred during the study, but patients in the HMB/GLN/ARG group reported fewer gastrointestinal complaints compared to placebo.

CONCLUSIONS

Dietary supplementation with HMB/GLN/ARG is better tolerated but not more effective in reversing cachexia in RA patients compared to the mixture of other non-essential amino acids used as placebo. Further controlled studies are necessary to confirm the beneficial anabolic and functional effects of increased nitrogen intake in this population.

Validity of reported energy expenditure and reported intake of energy, protein, sodium and potassium in rheumatoid arthritis patients in a dietary intervention study

OBJECTIVES

The aim of the study was to validate a diet history interview (DHI) method and a 3-day activity registration (AR) with biological markers.

SUBJECTS AND STUDY DESIGN

The reported dietary intake of 33 rheumatoid arthritis patients (17 patients on a Mediterranean-type diet and 16 patients on a control diet) participating in a dietary intervention study was assessed using the DHI method. The total energy expenditure (TEE), estimated by a 3-day AR, was used to validate the energy intake (EI). For nine subjects the activity registration was also validated by means of the doubly labelled water (DLW) method. The excretion of nitrogen, sodium and potassium in 24-h urine samples was used to validate the intake of protein, sodium and potassium.

RESULTS

There was no significant difference between the EI and the TEE estimated by the activity registration or between the intake of protein, sodium and potassium and their respective biological markers. However, in general, the AR underestimated the TEE compared to the DLW method. No significant differences were found between the subjects in the Mediterranean diet group and the control diet group regarding the relationship between the reported intakes and the biological markers.

CONCLUSION

The DHI could capture the dietary intake fairly well, and the dietary assessment was not biased by the dietary intervention. The AR showed a bias towards underestimation when compared to the DLW method. This illustrates the importance of valid biological markers.

Nutraceutical Therapies for Degenerative Joint Diseases: A Critical Review

There is growing recognition of the importance of nutritional factors in the maintenance of bone and joint health, and that nutritional imbalance combined with endocrine abnormalities may be involved in the pathogenesis of osteoarthritis (OA) and osteochondritis dissecans (OCD). Despite this, dietary programs have played a secondary role in the management of these connective tissue disorders. Articular cartilage is critically dependent upon the regular provision of nutrients (glucose and amino acids), vitamins (particularly vitamin C), and essential trace elements (zinc, magnesium, and copper). Therefore, dietary supplementation programs and nutraceuticals used in conjunction with non-steroidal, anti-inflammatory drugs (NSAIDs) may offer significant benefits to patients with joint disorders, such as OA and OCD. This article examines the available clinical evidence for the efficacy of nutraceuticals, antioxidant vitamin C, polyphenols, essential fatty acids, and mineral cofactors in the treatment of OA and related joint disorders in humans and veterinary species. This article also attempts to clarify the current state of knowledge. It also highlights the need for additional targeted research to elucidate the changes in nutritional status and potential alterations to the expression of plasma membrane transport systems in synovial structures in pathophysiological states, so that current therapy and future treatments may be better focused.