Obesity and failing immunity

Philip J. Goscienski, M.D.

October 2009

Older persons are more susceptible to infectious diseases such as influenza H1N1 than younger ones are but is it really because of age? Maybe not.

When the influenza virus or any other disease-causing microbe enters your body it triggers a complicated response that, if successful, will limit the damage and eradicate the invader. This immune response has a built-in memory so that when another influenza virus comes along years or decades later the body will attack and dispose of it even faster. That's why survivors of the influenza pandemic of 1918 appear to have some resistance against the current H1N1 strain. And these folks are in their 80s or 90s!

There is no doubt that seniors are more susceptible to infections but it should be just the opposite. After all, they have been exposed to lots of germs over the years and they should have even better immunity than the rest of us.

There are two factors that might explain why the older population has such poor resistance: obesity and lack of physical activity.

In the 40-plus years between receiving the high school diploma and that first Social Security check the average American gains more than 30 pounds. An accumulation of fat is an invitation to all the germs in the neighborhood.

Surgeons are well aware that their overweight patients are more prone to infectious complications after an operation. Hospital-acquired infectious disease rates rise in lock-step with an increase in Body Mass Index (BMI). That's especially frightening during this era in which bacteria known as MRSA (Methicillin-Resistant Staph Aureus) prowl hospital corridors.

Obese persons got that way partly by enjoying a high-fat diet. A high intake of fat, especially saturated fat, depresses several different immune responses.

Lack of physical activity is the other major factor in obesity and it adds to immune deficiency. Resistance exercise, that which uses weights and exercise machines, is necessary for a strong immune system. Immune function improves even among older individuals who exercise regularly.

Nearly all persons with type 2 diabetes are overweight or obese. When cells that protect us from invading microbes cannot utilize sugar properly in order to obtain energy, engulf germs or produce protective antibodies the outcome can be grim.

Of 10 patients in Michigan who developed serious complications of influenza, 9 were obese or extremely obese. Three died. That should be a wake-up call for the rest of the nation.

Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at drphil@stoneagedoc.com.