Allergies, Arthritis and Immunity: The Food Factor
The link between food and immune responses, including arthritis or allergies, is as complex as the immune system itself.
By Mark Anthony, Ph.D. | 02/06/2006
Food as it relates to allergies involves more than avoiding peanuts. There are food ingredients believed to help allay the symptoms of allergies and asthma. For example, bee pollen is promoted as a remedy for seasonal allergies and the B vitamins thiamine and riboflavin have been touted as helping alleviate allergic reactions to mosquito bites.
The food-arthritis link has been investigated for centuries. For example, some researchers have suggested a causality in compounds called solanines, found in the nightshade family of plants, and includes potatoes, peppers, eggplant and tomatoes.
The FDA has not signed off on most foods promoted as disease- or symptom-ameliorating, and for a good reason: Many of the links between food and specific conditions are tenuous at best. But all maladies involve immunity, and immunity is a rapidly growing part of wellness foods, involving physical and mental function.
An Integrated System
The immune system is a highly integrated, complex web of specific and nonspecific branches. Nonspecific (“innate”) immunity is provided by a system of natural protective barriers to invading microorganisms. The skin and mucus membranes act as physical barriers. Friendly gut bacteria compete with invaders. Stomach acids and chemicals in the intestines can rupture bacterial cells and mark them for destruction by the body, and inflammation dilates the blood vessels and recruits other protective factors.
|Cherrybrook Farms — both the company and its products — came about because one of its founders developed food allergies as an adult and had difficulty finding baking mixes without dairy, eggs and nuts.|
Complementing the innate system is specific (“acquired”) immunity. This is the part of the immune system that can recognize and eliminate a virtually endless diversity of foreign proteins. This function is carried out by two types of cells that generate specific responses: lymphocytes and antigen-presenting cells.
Lymphocytes are either B-cells or T-cells. B-cells produce antibodies (immunoglobulins) to invading proteins. Once sensitized, they’ll remember the invader forever. T-cells can be either Cytotoxic Ts, which kill infected cells, or Helper Ts. Helper Ts produce chemicals called cytokines that coordinate the intricate actions of cell-based immunity.
Avoiding the Triggers
The most basic relationship between diet and immunity people face is avoiding specific foods that trigger allergies. Food allergies constitute a topic unto themselves, but a little background helps us understand how foods that help alleviate allergy symptoms might work.
Although most people have experienced a reaction to a food, it’s estimated that 8 percent of children age 6 years or younger, and 1 to 2 percent of adults, suffer from a true food allergy. Food allergies kill approximately 150 Americans (usually children) each year. One in three people alter their own or a family member’s diet because of a suspected food allergy.
An allergy is an exaggerated immune response to a common protein, food-based or otherwise. That response — an outpouring of histamine and other inflammatory proteins — can result in anything from gastrointestinal distress, nausea, and vomiting to rashes, swelling and bronchospasms that make breathing difficult. Symptoms can be mild, or turn fatal as blood pressure drops and swelling chokes off airways.
Eight types of food account for over 90 percent of all food allergies: dairy products, soy, shellfish, wheat, tree nuts, peanuts and egg whites. Since it’s often difficult to find common foods without these proteins, many food manufacturers are finding a market in providing foods free of these common triggers.
Pacific Foods helps to fill this niche with an extensive line of organic wheat-, gluten- and casein-free soups, milks and broths. The company is now offers ready-prepared meals, too. Entire companies, such as Cherrybrook Kitchen (www.cherrybrookkitchen.com), Lawrence, Mass., began as someone’s personal crusade to avoid food allergies. “My wife Patsy and I started Cherrybrook Kitchen after she developed food allergies as an adult. Patsy was suddenly faced with the difficult task of learning how to eat and cook without dairy, eggs or nuts. A self-professed chocoholic, she realized early on that there were no baking mixes on the market that could satisfy her sweet tooth and meet her allergy needs,” explains Chip Rosenberg, the company’s CEO and co-founder.
Responding to Inflammatory Response
The inflammatory reaction is an important interface between diet and immunity. Much of the discomfort and potentially severe complications that result from allergies is generated by our own reaction to the allergen.
The question of how to tame the defensive reaction has stimulated much nutrition research. One class of ingredients seeing an explosion of interest is omega-3 fatty acids.
The fats we eat can influence the intricate signals by which immune cells communicate. The most abundant fatty acid in cell membranes is arachidonic acid. We get it from foods like meat and eggs or indirectly by modifying linoleic acid, an omega-6 fatty acid found mostly in vegetable oils.
Arachidonic acid is converted to a group of compounds (collectively known as ecosanoids) that affect immunity, influencing fever regulation, vascular permeability, vasodilation, the proliferation of natural killer cells and lymphocytes and the production of cytokines. The result of all this action is to promote inflammation. In theory, by displacing some of the arachidonic acid in the immune cells, different ecosanoids are produced whose actions are anti-inflammatory.