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|Immunity Issues Discussed at Oley Conference|
A wealth of information was shared during the conference plenary sessions on immune status protection. Below are some of the highlights from Dr. Calabrese’s talk on exercise and immunity and Dr. Lipman’s talk on nutrition research. Many thanks to all of the presenters for their valuable contributions.
Part I: Improving the Immune System with Exercise
Leonard Calabrese, DO, FACP, The Cleveland Clinic Foundation, Cleveland, OH
The human body develops three types of immune cells which together create an orchestra of immunity. The three cell types are known as T cells, B cells and NK or natural killer cells. Each works together to defend the body.
Basically their are two types of exercise. The first is acute which is short in duration (less than 50 minutes) and can be graded maximal or exhaustive. The second we will refer to as trainingand is characterized by repetitive, intensive activity intended to improve body systems.
Studies show that a moderate amount of intensive exercise or training can dramatically improve the effectiveness of the immune system - especially the NK and B cells.
For example, in one study, three groups of people were rated for their risk of catching the common cold. The first group spent little or no time at all exercising. The second group spent at least 30 minutes each day walking at a moderate pace, and the third group undertook repetitive, exhaustive exercise. Members of the group performing a moderate amount of exercise were least likely to catch a cold.
Another study tracked upper respiratory infections in middle aged, moderately obese women. The first group of women were relatively inactive during the study, retaining their habit of limited exercise. The second group of women undertook a moderate exercise program that involved walking 45 minutes per day, five days per week at 60 percent of their maximum heart rate. The researchers found that the women who began exercising regularly experienced significantly less frequent and less severe upper respiratory infections than the women who remained inactive.
Other studies have shown that moderate amounts of regular exercise can have positive long term effects on the immune system. Even a modest, exercise program of 20 minutes per day can boost natural killer and B cell functions.
In addition to improving the immune system, exercise lowers the risk of some important diseases and has positive psychological effects. Thus, I encourage you to start with whatever exercise you can do, and to build slowly until you reach your goal.
Part II: Rats, Medical Inquiry and Diversity
Timothy Lipman, MD, Dept. of Veterans Affairs Medical Ctr., Washington, DC
The gut is a major immune system organ. In fact, almost all immune cells go through the gastrointestinal (GI) tract. Unfortunately, what happens to normal immune function when the GI tract is missing or damaged is largely unknown. As researchers continue to study this area, patients need to recognize the importance of dietary diversity and understand how we really know what we think we know.
Classic nutrition focuses on discovering what are the bare minimum, or “essential” nutrients needed. These researchers might be called “reductionists.” HomeTPNers - those people living totally on minimal nutrients - are the story of success for reductionists.
A new thrust in nutrition research seeks to determine an “optimal” diet. In other words, what beyond the basics is needed in the diet. Thus, these “expansionists” research the so-called “conditionally essential” and “non-essential” nutrients. These are nutrients which you normally don’t need, but under certain conditions (such as gut deficiencies), they may be necessary. Glutamine is an example of a conditionally essential nutrient.
Expansionists also study the wider picture of health and dietary habits. For example, in one survey researchers tried measuring the affects of dietary diversity on a person’s overall health. The researchers found that people who regularly ate two or less items from each of the five food groups had higher overall mortality as compared to those with a more diverse diet. Studies like this remind us that diversity in diet is important, and that the bare minimal nutrients may not meet all of our long term health needs.
Is the Study Applicable to Me?
A second point relates to the issue of sifting through research information, deciding which is true and applicable to humans. Many nutrition studies are done on rats and the findings are not necessarily true for humans. Rat GI tracts are very different from human GI tracts and may react differently to the same stimulus. For example, translocation of bacteria from rat intestines is a common occurrence when the rats are put on TPN. This same phenomena does not appear to occur in humans. Likewise, researchers have shown that glutamine has effects in rat intestines, but we won’t know its affects on human intestines until research on human intestines has been completed.
The information gleaned from animal studies should be used as springboards to human clinical research. Ultimately, we are always asking the question whether some intervention “X” will achieve a result “Y.” Many times with homePEN individuals, an individual “experiment” results from trial and error attempts to see which food works for the individual. Unfortunately, because of the powerful successful treatment effects of a placebo - we want an intervention to work - scientists cannot generalize the findings from an individual to a large group. When the trial consists of only one individual, it can never be known whether the results are due to the intervention itself, or due to the placebo effect. To know whether an intervention is truly effective, you need large prospective, randomized, “blinded” clinical trials. Unfortunately, these studies are difficult to perform and expensive, but they are the only way to find answers to many of the important questions facing homePEN individuals. In conclusion, patients should recognize that:
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