Considerations in the prevention of seasonal allergic rhinitis

Townsend Letter for Doctors and Patients, May, 2005 by Jason Barker, Chris Meletis

Allergic/inflammatory processes become active in the gut; transportation of food proteins across the intestinal wall becomes altered resulting in increased permeability and motility of the intestine. (7) Coupled with other conditions such as intestinal infections/flora imbalance and decreased secretory IgA may lead to further intestinal compromise and increased antigen-immune interaction. Thus, we may hypothesize that not only will increasing the antigenic load in the form of food allergy/sensitivity increase the food allergy problem; it will also overburden the immune system, possibly leading to overreaction against airborne or other seasonal allergens.

Milk is an interesting food to look at while on the subject of food allergy. Commonly thought of as an allergen (especially incorrect in those with lactose-intolerance) because of its ability to increase mucus secretion, this was evaluated in one interesting study. Investigators looked at people's sensations and symptoms immediately after drinking milk and a 'placebo milk'. (8) The study went like this: 169 subjects, 70 of whom believed that milk leads to increased mucus production, were enrolled in a randomized, double-blind trial of a "flavored" cows' milk drink and a similar-appearing and tasting soy milk drink. In a pretest of 185 people, the researchers claim that the two drinks were indistinguishable. A survey was administered to each subject in both groups asking them to rate 14 milk-mucus indicator variables; only 3 of the 14 variables were elevated in both groups. They were: "coating/lining over the mouth, throat or tongue," "need to swallow a lot" and "saliva thicker, harder to swallow than before." Investigators concluded, in their oft-quoted study, that milk does not increase mucus, and the sensation of increased mucus production can be duplicated after consuming a soy drink as well, thereby negating the claim that milk leads to increased mucus production.

What is most interesting (and the biggest flaw) about this study is that researchers looked only at immediate reactions to mucus production without looking at longer-term outcomes (hours to even a day later). Clinically, many people with allergies are averse to milk, as are people like athletes, singers, and speakers, or for that matter anyone whose performance may be affected by excess mucus production. Another study looking at mucus production hours after milk consumption is in order here.

Preventive Measures

Preventing the allergic response is of course, our first line against this condition. Preventive approaches can take place as early as gestation and throughout infancy. While prevention always makes the most sense, there are other treatment strategies for adults with allergies as well.

Hygiene

A discussion about inflammation, especially allergic, is not complete without mention of the Hygiene Hypothesis. The central tenet of this hypothesis states that increases in hygiene have led to an immune system left unchallenged. The widespread use of antibacterial cleaners and the intense methods in which children are prevented from encountering 'germs' may have led to an increase in atopic disease. The hypothesis was created after patterns of risk factors for allergic disease in Europe; apparently hygienic practices have removed a protective influence against allergic disease by reducing the number of infectious challenges early in life. (9) That is, as young children are exposed to and become infected by various agents, the immune system is kept 'busy' combating these infections. Now that modern medicine and intense hygiene (food that falls on the floor is never eaten, hands are washed several times a day, and great alarm occurs if dirt, rocks or other 'unclean' items are placed in the child's mouth) have removed much of the infections that previous generations suffered, the modern immune system now reacts against typically benign environmental substances, i.e. animal dander and pollens.