Monday, November 07, 2005

The Concept of Allergy

The concept of immune responses to food antigens is useful in understanding many diseases. Many of the major unsolved disease of our civilization are either degenerative and/or inflammatory and many are recognized to be inflammatory, immune-mediated, hypersensitivity diseases. In this review, a general theory of hypersensitivity disease as a continuum of disease-causing mechanisms is presented.

The term "hypersensitivity" refers to immune-mediated processes that lead to disease. For over 20 years, I have considered the possible role of food antigens in causing or contributing to immune-mediated diseases and looked for opportunities to help patients with simple and safe therapeutic strategies such as diet revision. The original concept of allergy included all immune-mediated disease and the term allergy was interchangeable with the term "hypersensitivity."

Allergy can be thought of as hypersensitivity disorders with external causes. Substances that trigger allergic responses are antigens. These are often proteins that can be found in air, food and water. Airborne antigens such as plant pollens or house dust are well known. Other airborne antigens and food antigens are less obvious. New and foreign substances introduced to the body such as drugs and herbs cause allergic reactions.

Food materials should be given priority consideration since this is the biggest chunk of the environment to get inside human bodies and to interact with immune networks. If the term "food allergy" refers to all interactions between molecules derived from the food supply and the immune system, then many hypersensitivity disorders fall into the category of food allergy. Diverse manifestations of food allergy can only be understood if different patterns of immune activity are appreciated. It is unreasonable to believe that all food allergy can be detected by skin tests or any other simple test.

The first distinction that recurs in the allergy literature is between immediate and delayed patterns of allergic reactivity that loosely correspond to IgE-mediated allergy and non-IgE mediated responses. Many authors refer to the original four categories of immune-mediated injury defined by Gell and Coombs. The concept of four mechanisms is just a starting point for understanding immune-mediated disease. These very complicated defense-injury sequences cause a variety of disease states.

The immediate or type 1 allergy pattern is easily recognized because it involves quick and dramatic symptoms. Hay fever is the most common type 1 allergy and can be diagnosed by allergy skin tests and by IgE antibody tests such as RAST or ELIZA. Delayed patterns of allergy are not so obvious and generally go unrecognized. Allergy skin tests do not show this problem. Symptom onset is delayed many hours after exposure to the trigger. Allergic reactions to drugs such as penicillin and to foods involve delayed hypersensitivity.

The advocates of a broad definition of food allergy run the risk of being evangelical. The conviction that food allergy is a ubiquitous cause of disease comes from knowing the benefits of careful diet revision in medical practice. Many books in the popular literature proclaim the benefits of diet revision and a ground swell of interest and concern has engaged an ever-enlarging group of patients.
Often, the patient who benefits from proper diet revision is distanced from a medical profession who is either not interested or denies the problem of food allergy. Some of the issues that arise are semantic and political, but other issues involve the very complex biology of food-body interactions that are not well understood. Other issues involve the changes in the food supply that have accelerated in the past few decades.

When you do not know about food allergy, you are surrounded by mysterious diseases. When you know about food allergy, several common illness patterns begin to make more sense. Linda Gamlin writing about food allergy in the New Scientist stated that:

"Evidence is growing that many debilitating and chronic symptoms of ill health come from an intolerance for certain foods… The medical establishment remains largely hostile to the notion, leaving the field open to the medical fringe… the main problem is the plethora of symptoms and the variations from one patient to another. Doctors working with food intolerance report more than 40 possible symptoms and conditions...the severity also varies. Some patients are said to have nothing more than the occasional migraine or bout of fatigue, while at the other end of the scale the sufferer is unable to work or lead any sort of normal life."

In response to allergy lobby groups in the USA, the US Congress passed a bill that requires notice on the labels of foodstuffs that contain eight of the most common food allergens. The Food Allergen Labeling and Consumer Protection Act, will require plain English labeling by the year 2006 of products containing wheat, milk, soy, peanuts, tree nuts, fish, shellfish, or eggs. These account for an estimated 90% of all food allergies. The bill also requires the Food and Drug Administration to develop a definition of the term "gluten-free" to help those with celiac disease and who require a gluten free diet for other reasons.

See Allergy and Immunology by Stephen Gislason MD

Saturday, November 05, 2005

What is Intelligence ?

The central feature of intelligence is the ability to understand what is really going on out there and to respond to events with successful and adaptive behavior. Intelligence is built from subsystems that sense, decide, remember and act. It is fashionable to speak in terms of "mental abilities" and to list a number of different mental abilities. Obvious differences in individual mental abilities are measured with standardized tests which are then correlated with performance in school, skills learned, and with other socio-economic measurements. Intelligence test measurements tend to be used as a short-form for general intelligence. Arguments arise when test results are not congruent with preconceptions and vested interests.

Leda Cosmides and John Tooby suggest:

“The brain is a naturally constructed computational system whose function is to solve adaptive information-processing problems (such as face recognition, threat interpretation, language acquisition, or navigation). Over evolutionary time, its circuits were cumulatively added because they "reasoned" or "processed information" in a way that enhanced the adaptive regulation of behavior and physiology....our minds consist of a large number of circuits that are specialized. For example, we have some neural circuits whose design is specialized for vision. All they do is help you see. The design of other neural circuits is specialized for hearing. All they do is detect changes in air pressure, and extract information from it. Still other neural circuits are specialized for sexual attraction -- i.e., they govern what you find sexually arousing, what you regard as beautiful, who you'd like to date, and so on.… you can view the brain as a collection of dedicated mini-computers -- a collection of modules… whose operations are functionally integrated to produce behavior...So it is with your conscious experience. The only things you become aware of are a few high level conclusions passed on by thousands of specialized mechanisms: some that are gathering sensory information from the world, others that are analyzing and evaluating that information, checking for inconsistencies, filling in the blanks, figuring out what it all means.“

The other day, I was in the hardware store getting some plumbing parts and I heard one clerk tell his colleague: "If you yawn, that means there's no oxygen. I mean if you walk into a room and start to yawn there no oxygen there. It's a fact!" Perhaps the clerk should get an award for attempting science but he did not get it right. He is manifesting the human tendency to develop explanatory systems with the information at hand. Everyone has a science and technology. The question is how intelligent and up-to-date is your version of science and technology?

Many people are content with the most available explanations and will not make the effort or do not have the ability to study current science and technology. Some people are quite satisfied with explanations provided by astrology, for example, and make no effort to learn the up-to-date sciences of astronomy and psychology. Astrology might have been a viable science 1000 years ago but in the 21st century, astrology is a historical curiosity that should be in a museum and not in daily use. Irrational explanations reflect a deep human tendency to interpret events superstitiously and with exaggerated self-reference. Advanced education, carefully modeled and supervised by more rational teachers is required to replace irrational explanations with more rational ones.

Common usage of the word "intelligence" involves a scale, not a single value or entity. Humans rate each other on a scale of smart to dumb, or bright to stupid. The idea is that intelligence varies and this means that the ability to understand what is really going on out there is unevenly distributed in any human population. The ability to respond to events with successful and adaptive behavior is a variable expression of intelligence.

The problem with the hardware store clerk's assertion is that the premise is wrong. No oxygen leads to coma and death, not yawning. And yet, there is something appealing about the clerks' interest in the problem and his certainly that he knows what is really going on. His statement is representative of an entire class of human statements that sound like intelligent remarks but are not. When people do not really understand what is going on out there, their statements are wrong, their actions are wrong and the consequences of their actions can be harmful to themselves and others. Some of the errors can be attributed to the habits of a lazy mind, to ignorance, misinformation and some of the error to lack of innate ability. You could imagine a very bright child who was taught all the wrong things at home and at school, he or she would make mistakes because of no information or misinformation. You could also imagine a not-so smart child who was taught all the right things but did not understand or forgot.

The real question is: How do the innate determinants of intelligence and learning interact? You might observe some bright children who were taught all the wrong things and at some point in their life, realize that their teachers misled them and invent new ideas and new strategies, learning through their mistakes. The adaptive principle of intelligence suggests that if you got the wrong direction and the wrong information from your parents and teachers and you are smart, you have a chance to discover your own truth.

From the The Book of Brain

by Stephen J. Gislason MD