The Impact of Arthritis
Millions of individuals around the world live with arthritis daily. An estimated 15% of people in the United States are affected by this disabling disease. The economic burden of arthritis is immense. The cost from medication expenses to missed days of work in America is several billion dollars yearly. The two most prevalent forms of arthritis are osteoarthritis (OA) and rheumatoid arthritis (RA). OA is the most common joint disorder and is a leading cause of disability and pain, especially among the elderly. Over half of individuals over the age of 65 have radiographic (x-ray) evidence of OA. An estimated 80% of those in their eighth decade of life show signs of OA. Fortunately, not every person develops symptoms. While it is less common than OA, RA also affects millions of individuals worldwide, with an estimated prevalence from 0.3-1.5% of the population in North America. RA can occur at any age, with a peak incidence between the fourth and sixth decades of life. Although their causes and disease courses differ, both OA and RA can result in significant and disabling joint pain and damage with impaired activities of daily living, and substantial healthcare costs.
The Arthritis Diet – Treatment Beyond Medication?
Today there are many medications that are used in the treatment of arthritis. The main drug treatments for OA are primarily focused on pain relief and anti-inflammation. Drug treatment in RA also focuses on pain relief and anti-inflammation, as well as medications known as DMARDs (disease modifying anti-rheumatic drugs), which aim to prevent further joint damage and progression of RA. Although drug therapy has proven to be beneficial in arthritis treatment among a majority of patients, the medications are not without risks. It is the undesirable side-effects and high associated costs of drug treatment that has motivated many patients to seek relief in what are commonly termed “alternative therapies.” Within this realm of alternative therapy is something that is a fundamental part of our daily lives—nutrition.
Note to Readers
For the purposes of this article, nutrition can be defined as a substance that provides nourishment to the body. This includes not only the food and beverages ingested daily, but also such things as cooking oils, vitamins, and other supplements. Many studies have looked at various components of nutrition and the effects of these components on arthritis and other diseases. Unfortunately, while there is no shortage of studies on nutrition and arthritis, there are several conflicting data regarding the relationship between nutrition and the development, progression, and symptoms of arthritis. Controlled studies of diet and nutrient supplementation effects on OA and RA are inherently difficult due to variability in clinical course of disease and the wide variety of individual responses to nutrition. The use of dietary questionnaires and varied adherence to assigned diets by study subjects also make an accurate and scientific study of nutrition very difficult.
While there may be evidence supporting the benefits of a certain diet or nutrient for arthritis treatment or prevention, this does not imply a direct causal relationship. For example, a study that shows a significant association between Vitamin D intake and a decreased incidence of RA does not imply that taking more vitamin D will prevent RA in everyone. Rather, it offers evidence that a relationship exists between increased vitamin D intake and decreased chances of developing RA.
The importance of medications in the treatment of arthritis should not be forgotten. Despite the cost and potential side-effects of traditional drug therapy for arthritis, millions of dollars are spent and numerous clinical trials are completed to ensure the efficacy of these medications. Sufficient evidence must be shown that medications are effective in the treatment of arthritis before these drugs are made available to patients. Unlike their alternative therapy counterparts, arthritis medications are followed closely to ensure their integrity and recognize significant side-effects associated with them. Herbal and over-the-counter remedies are currently exempt from legislation governing conventional medications. With this in mind, one should consider nutritional and supplemental treatments of arthritis as potential enhancements to traditional, proven medical therapy. Although nutritional adjuncts are often used for arthritis treatment, patients may be hesitant to report these uses to their doctors. Before beginning any change in arthritis treatment, including nutritional and dietary approaches, patients should be sure to speak with their physicians and discuss the potential benefits and side-effects of their new treatments.
The remainder of this article will focus on the two most common forms of arthritis, RA and OA, and provide some information on the role of nutrition in their development, progression, and potential alleviation.
Nutrition and Rheumatoid Arthritis
Rheumatoid Arthritis (RA) is a systemic inflammatory disease that typically occurs in the synovial membrane of joints, including the cervical spine, fingers, wrists, elbows, feet, and others. The chronic inflammatory process of RA can eventually lead to severe joint dysfunction and deformity. Although the exact mechanisms are unknown, the role of the immune system is considered paramount in this autoimmune disease. Specific components of the body’s natural immune system, such as T-cells and cytokines, have been implicated as the major players in RA and its progression. Within this paradigm, studies have generally tried to explain both the benefits and ill effects of nutritional components on their ability to modulate inflammation and inflammatory substances in the body. There is a genetic component to the development and progression of RA. However, many believe that environmental triggers, such as nutrition, can also play a role in RA, especially in those who are already genetically susceptible. Despite variation among study outcomes, several nutritional components have come to the forefront as candidates in the prevention and treatment of RA. A study involving 238 RA patients in England found that 44% of these individuals had used some sort of herbal or over-the-counter remedy in a 6 month period. Following are some of the more widely studied nutritive components and evidence supporting or disputing their use in the treatment of arthritis.
Omega-3 Fatty Acids and Fish Oil
Omega-3 fatty acids, also called n-3 PUFAs (polyunsaturated fatty acids), are a naturally occurring component of certain foods and oils. Omega-6 fatty acids are another type of PUFA. Omega-3 and Omega-6 fatty acids are distinct and have opposing physiologic functions. Metabolism of omega-6 PUFA produces arachidonic acid (AA), which leads to certain pro-inflammatory cellular products. In contrast, metabolism of omega-3 PUFA, produces docosahexaenoic (DHA) and eicosapentaenoic acid (EPA), which have anti-inflammatory effects that balance that of omega-6 fatty acids. Major omega-6 and omega-3 PUFAs are linoleic and alpha-linolenic acid, respectively. The body cannot produce these substances making them essential to the diet. It is thought that the increased consumption of omega-6 PUFA-rich vegetable oils, such as sunflower oils and spreads in today’s Western diets, has dramatically increased the ratio of omega-6 to omega-3, shifting the balance of cellular products to a more pro-inflammatory state.
Sources of omega-3 fatty acids include: Flax seeds, seafood and fish such as chinook salmon, halibut, shrimp, and scallops, walnuts, cooked soybeans, raw tofu, winter squash, green leafy vegetables, as well as flaxseed oil and soya bean oil. Dietary sources rich in omega-3 PUFA can increase omega-3 fatty acid tissue concentrations, but these concentrations are hard to obtain in a regular diet. For this reason, and due to concern over mercury and other toxins in fresh fish, fish oil has recently become a popular supplement. Fish oil contains a high content of omega-3 fatty acids and are most often available in coated gel capsules. Dosages vary, and most recommended dosages can be quite high, in excess of 3-4 grams. People with diabetes, bleeding disorders and patients on blood-thinners should take caution when taking large doses of fish oil. Always discuss the potential risks and side effects before starting any new supplement with your doctor. In addition to health benefits in heart disease and several other conditions, beneficial effects of dietary supplementation of fish oil on RA has been observed in at least 13 double-blind, placebo controlled studies since 1985. A common feature of the studies has been a reduction in symptoms and in number of tender joints. Decreased morning stiffness and decreased dose of analgesic medications were also noted. One study reported a significant reduction in NSAID (non-steroidal anti-inflammatory drug) usage in patients receiving a fish oil supplement compared with those taking a placebo.
Olive oil contains large amounts of an omega-9 MUFA (monounsaturated fatty acid) called oleic acid. Metabolism of oleic acid produces eicosatrienoic acid (ETA). Similar to omega-3 products, ETA competes with omega-6 PUFAs, tipping the scales to a less inflammatory state. Some have hypothesized that the prevalence of olive oil in Mediterranean diets is one reason for the reduced incidence of arthritis in Mediterranean populations. In a Greek population, consumers of high amounts of olive oil (almost daily throughout life) were four times less likely to develop RA than those subjects who consumed the oil less than six times per month. Although olive oil studies are not as common as fish oil studies, there is some evidence for the potential benefit of olive oil in arthritis. One study found that RA patients who consumed olive oil capsules (6g/day) had significant reduction in pain and joint symptoms at 6 months and some patients were able to reduce their dose of NSAIDs by 400 mg of ibuprofen/day. Another study found a significant trend between increased olive oil consumption and decreased risk of RA development. Although the strength of these studies is not ideal, they do present a small amount of evidence that olive oil can be beneficial in countering the inflammation of RA. With a virtually absent side-effect panel and a delicious food influence, it is certainly not unreasonable for arthritis patients to explore the option of incorporating olive oil into their diet.
Some studies have looked at possible correlations between the consumption of red meat and the incidence of RA. Four controlled studies have looked at vegetarian diets and pooled results have implied that eliminating meat from the diet may be useful in the treatment of RA. These studies are difficult to interpret since the effect may be a result of excluding meat, or things such as increased fruit and vegetable intake (and subsequent vitamin C intake). One ecologic study including 16 countries demonstrated a positive correlation between the national prevalence of RA and the per capita consumption of red meat. Interestingly, another recent study from 2004 showed a higher level of total protein intake increased the risk of inflammatory arthritis by almost three-fold. The study concluded that high levels of red meat consumption is an independent risk factor for development of inflammatory arthritis, although they were unsure if this association was causative.
One concept that may explain this apparent association is that red meat provides a dietary source of arachidonic acid (AA), the aforementioned cellular product that is involved with production of pro-inflammatory molecules. In addition to AA, red meat is also a large source of iron. In animal studies, iron has been shown to accumulate in rheumatoid synovial membranes, causing tissue damage. There is also evidence of iron-catalyzed oxidative reactions, shown to be causative in worsening synovial inflammation following iron infusions. Ironically, iron-deficiency anemia is not uncommon among RA patients. Although not proven, it has been hypothesized that some of these anemia cases could be caused by uptake of iron by inflamed synovial tissue.
As individual needs and responses to diet may vary, arthritis patients should discuss any diet changes or reduction in dietary meat intake with their doctor and/or nutritionist prior to implementing any diet changes.
Coffee and Green Tea
Coffee and green tea, two of the most popular beverages in the world, have been tested in only a few arthritis studies, and they have produced conflicting inconclusive results. One study reported that greater than 3 cups of coffee per day, especially decaffeinated coffee, is a risk factor for RA development. Another recent study found no significant association between decaffeinated coffee consumption greater than 4 cups per day and risk of incident RA. This same study found no relationship between caffeinated coffee consumption over 4 cups per day, or regular tea consumption, and risk for RA. The Nurses’ Health Study is a very large, ongoing study of thousands of women. As of 2002, this study had found no significant association between drinking coffee or tea and the risk of RA. There are no human studies or evidence that green tea is effective for RA or other forms of arthritis. The anti-oxidant polyphenol compounds found in green tea are thought to reduce inflammation. As with many things, it appears that consumption in moderation may be the guideline for coffee and tea. However, one may wish to remove coffee from their diet for a period of time to see if its removal may prove beneficial for arthritis symptoms.
Vitamin C is well-known for its purported benefits with such things as the common cold and for its role as an anti-oxidant. Studies of vitamin C for the treatment of arthritis have produced mixed results. One animal study showed a decrease of inflammatory cell infiltration into synovial fluid (the fluid that is present between certain joints in the body) with the supplementation of vitamin C. One human study from 1999 failed to show any beneficial effect of vitamin C on the synovial inflammatory process. A population-based study of UK residents looked at dietary intake and found that over time, patients who developed inflammatory arthritis consumed less vitamin C than matched controls. A Framingham study found that a high intake of vitamin C was associated with a three-fold decrease in risk of OA pain and progression. There are many who advocate taking very large doses of vitamin C for many different things. Although vitamin C toxicity is rare, it is possible with extremely large doses. No acute dose causing toxicity has been identified, but a chronic dose of 2 grams/day has been quoted. Signs may include renal colic (ie, nephrolithiasis), diarrhea, nausea, and occult blood in the stool. Dietary sources of vitamin C include citrus fruits, green peppers, strawberries, tomatoes, broccoli, sweet and white potatoes.
The role of vitamin D in prevention of bone loss and building bone mass is well known. There are some studies that have looked at vitamin D intake and its correlation with RA. The Iowa Women’s Health Study looked at over 29,000 women and found that a greater intake of vitamin D may be associated with a lower risk of RA in older women. These results were not definitive by any means, but an interesting finding for further studies to build on. There are also animal studies supporting potential vitamin D benefit in RA. Arthritis patients taking steroids may be at risk for steroid-induced osteoporosis. Steroids can impair intestinal absorption of calcium. It is recommended that patients should at least meet recommended vitamin D as well as calcium dietary intake guidelines. Sources of vitamin D include cheeses, fortified milk and fortified cereals.
As with other vitamins and supplements, overdose is possible with very large supplementation.
Acute toxicity effects may include muscle weakness, apathy, headache, anorexia, nausea, vomiting, and bone pain. Chronic toxicity effects include the above symptoms and constipation, anorexia, polydipsia, polyuria, backache, hyperlipidemia, and hypercalcemia. Findings may also include calcinosis, followed by hypertension and cardiac arrhythmias. Acute toxic dose is not established, and chronic toxic dose is more than 50,000 IU/d in adults. In children, 400 IU/d is potentially toxic. A wide variance in potential toxicity exists. The recommended daily allowance is 400 IU for persons older than 1 year. Individual supplements are generally around 400 IU per tablet.
Vitamin E (alpha-tocopherol) is most frequently recognized for its anti-oxidant properties. Vitamin E deficiency and low tissue vitamin E has been reported to enhance inflammatory components of immune response. The ability of vitamin E to alleviate both OA and RA symptoms has been evaluated in studies, most of them of short duration. One study found that vitamin E worked better than NSAIDs for OA symptoms. Another molecular study demonstrated enhanced anti-inflammatory effects of aspirin with vitamin E supplementation, suggesting a reduction in the dosage of aspirin needed for RA symptoms. Other studies have produced conflicting results. Arthritis patients may find benefit with vitamin E supplementation. Recommended daily allowance is from 15-30 mg. Although it is very rare, toxicity can occur at very high doses. The potentially toxic dose is more than 3000 IU/d for 7-9 weeks. Supplements usually are 100-1000 IU per capsule. People with heart problems, or at risk for heart problems, should use Vitamin E with caution and only after a careful conversation with their doctor. While some studies have suggested improved cardiovascular health with Vitamin E supplementation, at least one study has shown that in people with a history of coronary artery disease, Vitamin E may negatively influence outcomes. Different medications may affect the relationship between Vitamin E and outcome. Again, as with starting any supplement, discuss the potential pros and cons with your doctor. Signs of toxicity from Vitamin E may include bleeding, especially in people taking blood-thinners. Dietary sources for vitamin E include whole grains, nuts, wheat germ, green leafy vegetables, and some oils.
It is hypothesized that selenium levels drop in response to inflammation and that selenium supplementation may have anti-inflammatory effects. Studies of selenium supplementation in RA patients have produced conflicting results. One of the largest studies reported a significant decrease in RA symptoms, reduced reliance on cortisone and NSAIDs, and a significant decrease in biochemical inflammation markers in a group receiving selenium. However, both placebo and study groups were receiving fish oil as well. Although levels of selenium are low in RA patients, it should be noted that the human body requires only very small amounts of selenium. Side-effects of selenium supplementation may include nausea, vomiting, nail changes, and fatigue. Good dietary sources of selenium include crab, liver, fish, poultry, and wheat. More studies on selenium supplementation in arthritis patients are needed to accurately evaluate any benefits it may have.
GLA (gamma-linolenic acid)
GLA is also known as evening primrose oil or black currant oil. Several studies have shown that GLA can ease RA pain and inflammation in humans. GLA is an omega-6 fatty acid that, unlike the other aforementioned omega-6 fatty acids, can possibly have an anti-inflammatory effect. GLA is available in capsules as well as oil, with a usual dosage of approximately 1800 mg per day. It is possible that GLA can enhance the effects of blood-thinners, leading to bleeding, as well as cause nausea, diarrhea, and abdominal pain. There are also potential drug interactions that can occur with GLA supplementation and one should always speak with a physician prior to beginning GLA supplementation.
Folate and B12
Folate and B12 may be of particular importance to those RA patients taking methotrexate, a very common DMARD used in the treatment of RA. A Cochrane review of seven trials described a positive effect of folic and folinic acid supplementation in reducing gastrointestinal side-effects of low-dose methotrexate in RA patients. A 79% reduction in mucosal and gastrointestinal side-effects were observed with folic acid supplementation alone, with no apparent differences between low and high dose folic acid. Patients taking methotrexate for their RA may want to discuss folic acid supplementation with their physicians.
Although it is not considered a nutrient, cigarette smoke is, unfortunately, a daily intake for many individuals. Cigarette smoking has consistently been found to be a risk factor for the development of RA and other inflammatory arthritis conditions. This risk factor is within every person’s control, and smoking cessation should be considered a top priority for arthritis patients. Following are a few links that provide assistance with smoking cessation:
Nutrition and Osteoarthritis
Osteoarthritis (OA), also known as degenerative joint disease, results primarily from the normal wear-and-tear of daily joint use. Over time the cartilage between bones begins to erode, leaving narrowed joint spaces, abnormal bone remodeling, often associated with pain. Unlike the systemic nature of RA, OA tends to be more focused, with a predilection for weight-bearing joints such as knees and hips.
Although OA is not considered an inflammatory disease, there is evidence for pro-inflammatory cells of the body playing a role in its development and progression. For this reason, it would appear that some of the nutritional supplements mentioned above for RA treatment could theoretically be beneficial in the treatment of OA as well. Although the vast majority of studies focusing on nutrition and arthritis are focused towards RA, it is not unreasonable for OA patients to discuss supplements and dietary factors with their physician.
One large study found that OA progressed three times faster in people who consumed low amounts of vitamin D. Others have shown that vitamin D intake decreased incidence and progression of hip OA.
There are two supplements that have been studied extensively for treatment of OA. Glucosamine is a supplement derived from the chitin shells of crab, lobster, and shrimp. Chondroitin sulfate is derived from cattle trachea. Both of these supplements have shown promise as alternative treatments of OA. Studies have provided evidence that both supplements can help with the pain and stiffness of OA, and possibly prevent further cartilage damage. Glucosamine and chondroitin sulfate are often sold as a combination in a single capsule. Many different brands exist, but one should be aware that the quality of individual brands may vary significantly. Although side effects are rare, it is possible that people with shellfish allergies could have a reaction to glucosamine. The recommended dose of chondroitin sulfate is 1200 mg per day, divided into two doses, while the usual glucosamine dosage is 1500-2000 mg per day taken in two doses.
The Impact of Weight on Osteoarthritis
A major risk factor for OA is excess body mass. Population-based studies have shown that overweight people carry a greater risk of knee OA than people of average weight. Extra weight increases risk for getting OA in knees and possibly hips, especially in women. In men, extra weight can also increase risk for gout. Long-term studies also suggest that obese individuals with knee OA are at greater risk for disease progression and weight loss may decrease the symptoms of knee OA. Research in 2004 demonstrated that exercise and diet together significantly improve physical function and reduce knee pain in people older than 60 who are overweight or obese, according to both the Arthritis Foundation and the American College of Rheumatology.
Maintaining normal weight is a crucial component in the prevention of OA, as well as in managing the symptoms and progression of OA. Faced with the obesity epidemic in the United States today, people are increasingly at risk for development of OA. OA and obesity can interplay in a potentially vicious cycle. Weight loss and exercise are clearly beneficial, but as OA symptoms progress it can become difficult to tolerate exercises. For this reason, exercises that decrease weight bearing such as biking, running on an elliptical machine, and swimming are often recommended.
Obese individuals often show an increase in inflammatory molecules in their system, and weight loss is usually associated with decreased concentrations of these inflammatory substances in the circulation. One study looked at the effect of weight loss on production of inflammatory molecules from adipose (fat) tissue. Results showed that weight loss resulted in decreased expression of inflammatory markers in the fat tissue of subjects, as well as an increase expression of anti-inflammatory molecules. Another study looked at the knee joints of 142 obese and overweight OA patients, and the effect of an 18-month diet and exercise trial on the forces placed on these joints. The results showed a significant association between weight loss and the forces applied to knee joints. They concluded that each pound of weight lost resulted in a 4-fold reduction in knee loads. An additional study showed that weight loss of 11.2 pounds over a 10-year period decreased the likelihood of developing knee OA by over 50%.
Clearly, in terms of nutrition, weight loss through a healthy lifestyle and diet lies at the heart of the matter for OA prevention and treatment. Diet should be tailored to each individual, especially those with pre-existing medical conditions such as diabetes or food intolerances. The help of a registered dietician is never a bad idea. These individuals can be helpful in setting up diet programs and answering questions about nutrition and supplementation. They can also provide different menus and recipes to promote healthy variety in daily meals. Occupational and physical therapists are also a valuable addition to diet and exercise.
Jamison J. Engle, BA, University of Iowa Medical School, Iowa City, IA
Joseph E. Herrera, DO, Mount Sinai Hospital, New York City, NY