Can Diet Help Ease Joint Pain?

While I spend most of my day dealing with digestive woes, I'm increasingly asked about which diet or supplements can help ease chronic joint pain. Anecdotal evidence supports a wide variety of remedies - but do any of them truly work?

Large, well-designed research studies investigating dietary remedies for joint pain are lacking, but overall, the likelihood of therapeutic benefit depends on the type of joint pain. Because different conditions cause pain through different physiological mechanisms, different dietary remedies may be effective depending on the source of the problem. Here's what available scientific research can tell us:

-- Osteoarthritis is the most common reason for joint pain, affecting millions of older Americans. It is characterized by deterioration of cartilage between joint bones such as the knee, hip, elbow and knuckles. As cartilage wears away, adjacent bones begin to rub together, causing pain, swelling and loss of motion. The most common supplement used for pain reduction and improvement of joint function is glucosamine - commonly marketed in combination with another compound called chondroitin. It is also one of the most studied dietary supplements.

The research on glucosamine and chondroitin is surprising. A three-year study of glucosamine alone (in the form of glucosamine sulfate) at 1500 milligrams per day appeared to have a significant benefit in preventing the loss of joint space in the knee among 45-to 70-year olds with mild to moderate knee osteoarthritis in comparison with a placebo - thereby slowing the progression of osteoarthritis.

[Read: Take Aspirin at Night to Reap its Health and Beauty Benefits.]

Similarly, chondroitin alone has shown a benefit in hand pain and function at 800 milligrams per day, although the benefit appears more modest, and data are less conclusive. But interestingly, when the two compounds are combined into a single supplement in the form of glucosamine chondroitin, multiple studies have found no clinical difference in reported pain relief or function among patients over age 40 with painful osteoarthritis of the knee when compared with a placebo!

Some experts believe that combining glucosamine and chondroitin may result in too large a molecule to be well-absorbed, thereby inhibiting the availability of either potentially beneficial compound. Indeed, some of my patients find this combo supplement to cause gas or diarrhea - an indication that absorption may be poor. Bottom line? If you're interested in trying a supplement for osteoarthritis, glucosamine sulfate alone may be a better bet than the more popular glucosamine chondroitin.

Tart cherry juice is rumored to be another cure-all for arthritis pain, due to an anti-inflammatory effect from its high antioxidant content, but no research studies to date have been conducted with osteoarthritis patients to prove this claim. Similarly, others have claimed a link between vegetables in the nightshade family - like tomatoes, peppers and potatoes -and arthritis pain. However, no scientific trials exist to support a benefit for dietary elimination in people with osteoarthritis.

[Read: Healthy Recipes With Tomatoes.]

-- Rheumatoid Arthritis (RA), an autoimmune disorder, causes inflammation in the lining of joints that results in pain, swelling, stiffness and eventually loss of function and deformity. It is especially common in the small joints of the hands, wrists and feet. Because of RA's inflammatory nature, research has focused on anti-inflammatory foods and supplements as being of possible benefit.

In some small studies, fish oil containing very high doses of omega-3 fatty acids has demonstrated considerable benefit over placebo in improving symptoms of pain intensity and morning stiffness - especially in early stages of RA - but it was not shown to slow progression of the disease. Similarly, small trials have found fish oil to significantly reduce tender joints and the reliance on over the counter anti-inflammatory drugs (NSAIDs) for symptom relief.

[Read: Top Recommended Health Products: Pain and Inflammation.]

Perhaps more compelling, however, is the evidence suggesting a diet higher in fish consumption for prevention of RA: One large-scale, prospective study of women ages 55 to 89 in Sweden showed a 29 percent decreased risk of developing rheumatoid arthritis among participants who consistently ate one or more servings of fish per week compared to women who ate less than one serving per week.

Bottom line: Eating fish regularly may be a good insurance policy for people at high risk for developing RA, and supplemental fish oil may have a modest benefit on joint pain among people who already have the condition.

-- Fibromyalgia is a condition in which widespread pain affects muscles throughout the body, with various "tender points" on the neck, shoulders, back, hips, arms and legs; it also results in fatigue and interferes with activities of daily living. Unlike osteoarthritis, it does not cause inflammation or damage to the joints. Fibromyalgia primarily affects middle-aged women, though its cause is not fully understood.

[Read: Yoga With Fibromyalgia: Carol Royal's Story.]

Very little is known about whether diet or supplementation is effective for fibromyalgia, and research is still in its infancy. A few small studies have investigated creatine supplementation as a dietary intervention. One recently published study showed creatine supplementation to be beneficial for improving lower and upper body muscle function in fibromyalgia patients, however, no improvement in pain or quality of life were observed.

Other studies have assessed creatine supplementation alongside exercise in patients with inflammatory myopathies (muscular diseases) and also resulted in improvements of functional performance. As there are some risks associated with supplemental creatine use, more research is required to determine whether these outweigh benefits.

Supplemental magnesium, a mineral stored in the bone and soft tissues that is involved with metabolism and nervous system functioning, has also been investigated on the basis of observations that many patients with fibromyalgia have lower magnesium levels than healthy individuals.

One small study of 80 pre-menopausal women with fibromyalgia showed that lower magnesium levels were significantly associated with more severe symptoms. It further found that supplemental magnesium citrate at 300 milligrams a day reduced both the number of tender points and symptom intensity; benefits were magnified further when participants took magnesium in conjunction with a prescription anti-depressant drug. While no conclusions can be drawn based on a single small study of this nature, the dose used in this study was within the safe limits determined by the Institute of Medicine and is therefore associated with minimal risk.

-- Gout is a painful, inflammatory joint condition caused by high levels of uric acid in the blood, which form crystals in the fluid surrounding the joints. Uric acid is produced as metabolic byproduct of foods high in compounds called purines. Dietary therapy for gout, therefore, limits foods and drinks that contain high levels of purines as well as other foods that contribute to high uric acid levels such as beer and fructose-rich beverages such as juice and soda.

[Read: Eat Your Calories, Don't Drink Them.]

Guidelines to prevent gout attacks among people who suffer from the condition include limiting alcohol intake to no more than one drink per day and drinking lots of water - as much as eight to 16 cups per day! Purine-rich foods that need to be minimized include organ meats; red meat such as beef, lamb and pork; fatty fish such as tuna and sardines; shellfish; and gravies or bouillons made with meat extract.

Plant foods that contribute to high uric-acid levels include asparagus, mushrooms, cauliflower, spinach, green peas, oatmeal, wheat germ and wheat bran. On the bright side, foods like coffee, dairy and vegetarian proteins (e.g. tofu, eggs, nuts and beans) may actually be protective.

Weight loss can help reduce the frequency of gout attacks among overweight people, though high-protein/low-carb weight-loss diets are NOT recommended with gout, as the excess protein intake can make symptoms worse. To wit: A young female patient of mine with a family history of gout once came in complaining of excruciating pain in her big toe within weeks of adopting a Paleo diet high in animal protein and low in grains, dairy and beans. Bingo!

As with any supplement regimen you're considering, talk to your doctor before starting, particularly if you take other medications that may interact. Given the poor regulation of dietary supplements, it's a good idea to vet your brand of choice online at consumerlab.com to ensure you're actually getting the dose claimed on the label.

[Read: Top 5 Foods to Fight Inflammation.]

Katie Casto Hynes, a a dietetic intern and master's degree candidate at Columbia University Teacher's College in New York City, contributed to this article.

Hungry for more? Write to eatandrun@usnews.com with your questions, concerns, and feedback.

Tamara Duker Freuman, MS, RD, CDN, is a registered dietitian whose NYC-based clinical practice specializes in digestive disorders, celiac Disease, and food intolerances. Her personal blog, www.tamaraduker.com, focuses on healthy eating and gluten-free living.

Please note that the author cannot offer individualized medical advice to readers who contact her via email.