November 2011 Issue
Is There a Link Between Nutrition and Autoimmune Disease?
By Sharon Palmer, RD
Vol. 13 No. 11 P. 36
Should you follow a Paleo gluten-free diet or a vegan diet? Should you pop omega-3 or turmeric supplements? About 23 million people in the United States who suffer from autoimmune diseases face these questions every day. The Internet is teeming with books, websites, and blogs offering advice on how to eat to prevent or treat autoimmune conditions. Unfortunately, much of it is based on hype and hope instead of solid scientific evidence.
What Is Autoimmune Disease?
Autoimmunity is the No. 2 cause of chronic illness, according to the American Autoimmune Related Diseases Association (AARDA), a nonprofit health agency dedicated to increasing awareness of autoimmune diseases. About 5% of the U.S. population has been diagnosed and treated for an autoimmune disease, and another 10% to 20% have early-stage autoimmune symptoms and imbalances, reports Paula H. Mendelsohn, MPH, RD, LD, CCN, a Florida-based dietitian who specializes in treating autoimmune diseases. About 75% of these cases occur in women, most frequently during the childbearing years.
When everything goes right, your body’s immune response is a marvelous defense system, protecting against foreign invaders, injury, and infection through a complex communication system between your body’s cells and the chemical signals they produce. In a healthy immune system, this communication is clear and specific; the body can tell the difference between a foreigner and itself. But in autoimmune disease, the immune response is flawed, and the communication system breaks down. The body’s immune system takes aim at its own tissues. Either the immune system can’t distinguish the body’s tissues from foreign cells and begins to attack itself, or it’s unable to regulate the intensity of the immune response. Regardless, the result is damage to the body’s tissues and the development of an autoimmune disease.
Autoimmune diseases can affect nearly every part of the body. Scientists have identified more than 80 clinically distinct autoimmune diseases, including systemic lupus erythematosus, type 1 diabetes, rheumatoid arthritis, Sjögren’s syndrome, multiple sclerosis, and chronic inflammatory bowel disease. For example, in Sjögren’s syndrome, your white blood cells attack moisture-producing glands, causing symptoms like dry eyes and dry mouth. And in type 1 diabetes, the immune system attacks the insulin-producing cells in the pancreas. People who suffer from autoimmune diseases often experience loss of function, disability, increased hospitalizations and outpatient visits, decreased productivity, and impaired quality of life.
Looking for Answers
Despite its prevalence, the level of basic autoimmune research funding is below 3% of the National Institutes of Health (NIH) total budget, which may explain why we understand so little about the roots of these diseases. Indeed, AARDA reports that the whole arena of autoimmune research is in its infancy. Though there are many theories about the origins of autoimmune diseases—such as the hygiene hypothesis theory, which suggests that the rise of such diseases in industrialized nations may be linked to cleanliness, vaccines, and decreased exposure to bacteria—scientists don’t fully understand why the immune system is unable to recognize its own cells or regulate its response; thus there are no sure cures or prevention strategies as of yet. We do know there are factors at the root of autoimmune disease development, which include both genetic and environmental components.
Currently, researchers are beginning to understand that autoimmunity may play an important role in many chronic conditions, such as cardiovascular disease. In fact, the NIH established the Autoimmunity Centers of Excellence to promote research in areas such as lupus, multiple sclerosis, pemphigus vulgaris, rheumatoid arthritis, scleroderma, and Sjögren’s syndrome. The goal is to foster collaborative research across scientific disciplines and medical specialties to find effective treatments and prevention approaches.
Role of Inflammation
A hot topic on the autoimmune disease front is the role that chronic inflammation—present in many autoimmune diseases—plays in its development. In rheumatoid arthritis, the damage to tissues is caused by an inflammatory reaction to the presence of antigens. Which brings to mind the old “chicken and the egg” question: Which comes first, inflammation or autoimmunity? “In rheumatoid arthritis, is it caused by inflammation and autoimmune disease comes secondarily, or is it caused by autoimmunity? The evidence is unclear,” says Noel R. Rose, MD, PhD, a professor of molecular microbiology and immunology and director of the Johns Hopkins Autoimmune Disease Research Center.
According to researchers, examples of autoimmune disease exist in the absence of overt inflammation and inflammation exists in the absence of autoimmunity. “Most autoimmune diseases aren’t caused by inflammation, although many autoimmune diseases cause inflammation,” Rose explains. “Some inflammatory processes may enhance the possibility of autoimmune disease in individuals with a genetic predisposition. Having inflammation may raise the likelihood of a subclinical autoimmune response reaching clinical thresholds. For example, this may occur in thyroiditis. We know that inflammation is caused by the same mediators often involved in the autoimmune process.”
The Autoimmune Disease Specialty
Your clients may be hard-pressed to find a dietitian—or even a doctor, for that matter—specializing in autoimmune disease. AARDA reports that modern medicine is organized on the basis of the anatomy of disease or in what part of the body disease occurs. There’s no specialty that focuses on autoimmunity; instead, an autoimmune disease is treated by the medical specialty that covers the particular anatomical part involved. Thus, dermatologists typically treat dermatological autoimmune diseases and gastroenterologists treat inflammatory bowel disease. But autoimmune diseases aren’t always neat and precisely limited to one body part or system—crossovers occur all the time.
It’s been established that if you have one autoimmune disease, you’re at higher risk for developing others. For example, in celiac disease, which is an immune-mediated enteropathy triggered by the ingestion of gluten-containing grains in genetically susceptible persons, the comorbidity between other autoimmune diseases has been documented. “There’s a correlation between celiac disease and other autoimmune diseases, such as type 1 diabetes, autoimmune thyroid disease, Sjögren’s syndrome, autoimmune liver disease, inflammatory bowel disease, and Addison’s disease,” says Shelley Case, RD, a celiac disease diet expert and author of Gluten-Free Diet: A Comprehensive Resource Guide. “For example, the prevalence of celiac disease in type 1 diabetes is between 5% and 15%,” she says.
Case asserts that dietitians need to be aware of these connections and that patients with these autoimmune diseases should be screened for celiac disease if they present with any symptoms related to gluten sensitivity. Case adds, “Dietitians need to specialize in autoimmune diseases such as celiac disease, as they are very complex conditions. Dietitians can do more harm than good if they just dabble in it. If dietitians don’t know this area well, they should refer a patient to a dietitian specializing in the specific autoimmune disease. That’s why family physicians frequently refer [patients] to specialists; we should have dietitian specialists, too.”
Dearth of Dietary Treatment Strategies
One thing most people in the autoimmunity field agree on is that there’s a lack of evidence-based information about dietary treatments for autoimmune diseases. “We don’t have any good evidence that an immunologically healthy diet is any different from any other diet. The best we can suggest is to follow the same good diet and exercise program to attain general health,” Rose says.
It’s important, however, to consider nutritional red flags that may arise during the management of autoimmune conditions. Typical drugs used in treatment, such as analgesics and nonsteroidal anti-inflammatory drugs, corticosteroids, disease-modifying drugs, and biologic response modifiers, may cause side effects such as nausea and vomiting, stomach pains, mouth sores, and decreased appetite. And some drugs can interact with specific nutrients, such as folic acid and vitamin B12. In addition, alterations in energy and protein metabolism that lead to muscle loss and wasting may occur in some autoimmune diseases.
The nutritional management of autoimmune diseases usually emphasizes controlling pain and inflammation, slowing the progression of the disease, and boosting the immune system. And a few promising foods and nutrients are emerging as potentially beneficial.
Let in the Sunshine Vitamin
Perhaps the most intriguing area of nutrition research involves vitamin D. For decades, researchers have noticed a relationship between sunlight exposure and vitamin D intake and autoimmune disease risk. “Some studies have found that people with autoimmune diseases such as multiple sclerosis are more likely to have lower levels of vitamin D than other people,” Rose says. “Many autoimmune diseases are more common if you live further from the equator. This is true for both multiple sclerosis and type 1 diabetes and probably for lupus.”
Many studies have explored the association between vitamin D and autoimmune disease. A November 2001 study published in The Lancet that followed participants for 30 years revealed that children born in Finland in 1966 who received supplemental vitamin D during the first year of life had a significantly lower risk for developing type 1 diabetes, while children with vitamin D deficiency during the first year of life had a significantly higher risk for developing type 1 diabetes. The Iowa Women’s Health Study found a lower risk of rheumatoid arthritis associated with higher vitamin D intake, according to the January 2004 issue of Arthritis & Rheumatism.
Several studies suggest that vitamin D may lower the risk of developing multiple sclerosis, as well as lessen the frequency and severity of symptoms. According to Michael Holick, PhD, MD, director of the Vitamin D, Skin, and Bone Research Laboratory at Boston University School of Medicine, if you’re born below 35˚ latitude, located approximately at Atlanta and live at this latitude for the first 10 years of your life, you have a 50% reduced risk of developing multiple sclerosis. In addition, he reports that women and men who increase their vitamin D intake to more than 400 IUs per day reduce the risk of developing multiple sclerosis by approximately 40%. The Nurse’s Health Study also found a protective relationship between vitamin D supplements and multiple sclerosis risk, as was reported in Neurology in January 2004. And in a new study published in September in Neuroepidemiology, data from participants enrolled in the Multiple Sclerosis Surveillance Registry suggested that exposure to vitamin D before multiple sclerosis onset may slow disease-related neurodegeneration and delay progression to disability.
How does vitamin D work in the immune system? In the 1970s, researchers discovered vitamin D receptors in many of the body’s cells, including islet cells of the pancreas, lymphocytes, and colon enterocytes. This led to the revelation that vitamin D helps keep the immune system functioning properly by inhibiting the proliferation of T cells and decreasing the production of proinflammatory cytokines.
“Vitamin D deficiency may be more common in this country than we assumed,” Rose says. “There seems to be suggestive evidence on the role of vitamin D, but we have much to learn. There are no clinical studies yet showing that giving large doses of vitamin D benefits autoimmune disease. The level that we need to prevent disease and maintain health may not be the same.”
The Microbiome and Autoimmunity
An up-and-coming area of human health research focuses on the impact of balancing the gut microbiota. Disruption of the intestinal ecosystem equilibrium has been linked with many diseases, including autoimmune disorders; thus prebiotics and probiotics have been called the “next frontier” in therapeutics by health researchers. Animal and some human studies have shown that probiotic cultures can enhance levels of immunoreactive cells, regulate immune factors, modulate immune dysregulation, and promote gut barrier function and anti-inflammatory responses.
Recently, the effects of probiotics on various autoimmune disorders have been investigated. Scientists are exploring how the microbiome (microbes, their genetic elements, and environmental interactions) may be different in children with type 1 diabetes compared with healthy children. In a January 2010 pilot study published in BMC Complementary and Alternative Medicine, a probiotic treatment resulted in improvement in pain and self-assessed disability in 45 adults with rheumatoid arthritis. And in a June 2006 review published in Postgraduate Medical Journal, Chinese researchers reported that preliminary studies suggest probiotics may be of benefit for colitis and inflammatory bowel disease because they may balance aberrant enteric microflora and reinforce the intestinal defense system.
To be sure, the research in the field of probiotics and autoimmunity is still preliminary. “Probiotics are more popular than they’ve ever been, but there are several things that we don’t know yet. If you add relatively minor numbers of bacteria, can you actually change the balance of bacteria normally inhabiting the gut? Is it always a good thing to change the balance in the gut?” Rose asks. Look for future studies to answer some of these questions.
Gluten Autoimmune Triggers
When it comes to celiac disease, the treatment is simple: Follow a gluten-free diet for life. “Other autoimmune diseases have no proven cause or cure, but we know that three factors play a major role in the development of celiac disease: Specific genetic markers HLA DQ2 and DQ8, consuming gluten, and certain environmental factors,” Case says. Recent studies have revealed that the bacterial composition of the gut may be one of the possible environmental factors behind celiac disease. Although more research is needed, we do know that if individuals are diagnosed early and follow a healthful gluten-free diet, the risk for complications such as osteoporosis, gastrointestinal cancer, and the development of other autoimmune diseases can be greatly reduced.
Today, going gluten free is a popular treatment for many other autoimmune diseases outside of celiac disease, including lupus, multiple sclerosis, and rheumatoid arthritis. But is there proof that this approach works? “There’s no evidence that gluten-free diets will help all autoimmune diseases. But I do believe that many people with certain autoimmune diseases may have undiagnosed celiac disease. Should you tell everyone to follow a gluten-free diet? No. First, they should get tested if they have symptoms of a gluten sensitivity because if someone already is on a gluten-free diet, the celiac tests can be falsely negative,” Case says.
Power of Omega-3 Fatty Acids
The potential benefits of omega-3 fatty acids in autoimmune disease also have attracted the attention of researchers. Omega-3 fatty acids, particularly those from fish oil—EPA and DHA—possess potent immunomodulatory activities, according to a 2002 review published in the Journal of the American College of Nutrition. The anti-inflammatory properties might make them useful in the management of autoimmune diseases; thus they’ve been investigated in conditions such as arthritis, Crohn’s disease, lupus erythematosus, multiple sclerosis, and rheumatoid arthritis—the latter being one of the most widely studied areas. In a May 2010 review published in Proceedings of the Nutrition Society, researchers from the Rheumatology Unit of Royal Adelaide Hospital in Australia reported that meta- and mega-analyses of randomized, controlled trials indicate reduction in tender joints and decreased use of nonsteroidal anti-inflammatory drugs with fish oil supplementation in long-standing rheumatoid arthritis. Other studies have found improvements in time to fatigue and grip strength related to fish oil consumption.
The evidence on using omega-3 fatty acids in the treatment of chronic inflammatory bowel disease has been mixed. While some studies found a decrease in proinflammatory cytokines, a January 2009 review in Cochrane Database of Systematic Reviews determined that the existing data indicate omega-3 fatty acids are safe but probably ineffective for maintaining the remission of Crohn’s disease. In an August 2004 double-blind, placebo-controlled trial published in the Journal of Rheumatology, omega-3 fish oils improved symptomatic disease activity in patients with systemic lupus erythematosus.
One approach dietitians can support is an anti-inflammatory, antioxidant eating strategy aimed at decreasing inflammation and oxidative stress and promoting a healthy immune balance. We know that inflammation goes hand in hand with autoimmune disease, but don’t underestimate the significance of oxidative stress. During an immune response, there’s an increase in the production of free radicals, which can result in oxidative stress—a process marked by a negative shift in the natural balance between pro-oxidants and antioxidants that results in biological damage. In fact, much of the damage in autoimmune disease can be linked to free radical damage to cell membranes and tissues. Studies have documented that oxidative stress and low antioxidant activity occur in autoimmune disease. The antioxidant vitamin E is deficient in 50% to 60% of patients with rheumatoid arthritis. And in a February study published in the Bosnian Journal of Basic Medical Sciences, multiple sclerosis patients were found to have a significantly lower antioxidant capacity compared with control subjects. While not many studies have examined the effects of eating a diet rich in anti-inflammatory, antioxidant foods and nutrients, most experts believe this approach is worth trying.
“Antioxidants play a role in autoimmune disease. Celiac disease is an inflammatory disease. We’re finding that long after people are diagnosed and are following a gluten-free diet, their guts aren’t healed yet. It can’t hurt for people to eat more antioxidant-rich fruits and vegetables,” Case says.
Donna Sigmond, MS, RD, a Colorado-based dietitian specializing in autoimmune diseases, enthusiastically recommends an anti-inflammatory diet to her patients. “I encourage green leafy veggies and other foods that can reduce inflammation, such as high-fat fish that contains fish oils. Seed oil from flax also can be beneficial. The focus should be to identify and eliminate inflammatory foods and nourish with real foods that deliver vitamins, minerals, and antioxidants,” Sigmond says.
In a study published August 15, 2006, in the Journal of the American College of Cardiology, researchers found that diets high in refined starches, sugar, saturated fats, and trans fats and low in fruits, vegetables, whole grains, and omega-3 fatty acids appeared to turn on the inflammatory response. However, a diet rich in whole foods, including healthful carbohydrates, fats, and protein sources, cooled it down. There’s no harm in supporting a diet—optimal for just about everyone—that’s rich in whole plant foods, such as fruits, vegetables, whole grains, legumes, nuts, and seeds; is rich in healthful fat sources such as extra-virgin olive oil, avocado, nuts, and fish; and includes foods such as tea, dark chocolate, spices and herbs, and red wine in moderation.
— Sharon Palmer, RD, is a contributing editor at Today’s Dietitian and a freelance food and nutrition writer in southern California.