Wednesday, July 7, 2010

Healthy living is its own reward

The proposition that we can sustain good health by jacking up our immune system is tantalizing, but bloody hard to prove. How sweet it would be if we could simply tweak our T cells through, say, diet and exercise and suffer fewer colds or maybe even fight off a more militant foe, like metastatic melanoma.

Supercharging our immunity may not be possible, however, no matter how much carrot juice we drink. The immune system is precisely that—a system, and not a single entity. To function well, it requires balance and harmony. Many of the intricacies of the immune response remain a mystery. For now, there are no direct links between enhanced immune function and what we eat and drink that can be scientifically proven, although you’d never guess it from the unregulated barrage of advertising to which we’re subjected.

This doesn’t mean the effects of how we live and what we consume aren’t intriguing and shouldn’t be studied. Researchers are exploring the effects of diet, exercise, age, psychological stress, herbal supplements, and other factors on the immune response in humans. Interesting results are emerging, but they remain sketchy as researchers break down how the immune system works and how to interpret measurements of immune function.

In a nutshell, the immune system is the system of specialized cells and organs that respond to outside biological influences. When the immune system is functioning properly, it protects the body against bacteria and viral infections, destroys cancer cells and neutralizes foreign substances. If the immune system weakens, so does its ability to defend the body, allowing pathogens, including viruses that cause common colds and the flu, to grow and flourish. The immune system also performs surveillance of tumor cells, and immune suppression has been reported to increase the risk of certain types of cancer.

As a cancer survivor, I figure the best way to remain one is to live as healthily as possible. This includes all the obvious things: no smoking, drinking in moderation, avoiding stress, exercising regularly and maintaining a healthy weight, eating my broccoli, getting enough sleep, etc. I’ve also posted previously on this blog about why I believe prayer and faith have an impact on my health. Knowing that cancer cells are on the loose in my body, my objective at this point is to give it the best possible chance to fight them off. Most of what I do is done in good faith, without much solid science to confirm my strategy. I’m OK with that since healthy living is its own reward. Should running have positively no impact on cancer progression, it still brings me great pleasure and a sense of well being.

Attempting to boost the immune system is devilishly complicated because there are so many different kinds of cells involved that respond to so many different microbes in so many ways. Which cells should you boost, and to what number? So far, scientists (and yogurt shop owners) don’t know those answers. What is known is that the body continually generates immune cells. In fact, it produces many more lymphocytes (a type of white blood cell) than it can possibly use. The extra cells remove themselves through a natural process of cell death called apoptosis—some before they see any action, some after a battle is won. No one knows how many cells or what kinds of cells the immune system needs to function at its optimum level.

When I was taking interferon two years ago, my oncologist kept a close watch on my neutrophil count. Neutrophils are the most abundant type of white blood cell and a critical part of the immune system. It was never clear to me why my white blood cell count fell as a result of my treatment, but the fact that it did repeatedly brought my adventure with interferon to a premature end. If the objective of immunotherapy is to boost the immune response to ward off cancer, then handicapping that process by knocking down WBC counts was obviously counterproductive.

I look back on that “lost summer” and wonder what, if any, effect my treatment had on the progression of my disease. It’s possible it helped, but that can’t be proved. Of course, had there been an optimum result from interferon, I would not have relapsed this last winter. The mechanism by which it sometimes works is poorly understood, as is true with most cancer drugs. Our approach to cancer therapy remains exceptionally crude.

There are a lot of interesting attempts being made to measure immune response to certain stimuli. One of the most benign I’ve seen involves nothing more than a walk in a park—or “forest bathing,” as the Japanese call it. In a series of studies, scientists found that when people swap their concrete confines for a few hours in more natural surroundings—forests, parks and other places with plenty of trees—they experience increased immune function.

Stress reduction may be one factor, but scientists also chalk up the response they’ve observed to airborne chemicals that plants emit to protect them from rotting and insects, and which also seem to benefit humans. That seems a little flakey to me, but there may be a germ of truth to it. Is my intuitive desire to garden an act of self-preservation? What we know for sure is that we are fearfully and wondrously made, and that includes an immune system that defies easy understanding. That complexity is the best reason for not staking confidence in immune-boosting strategies that make unsupportable claims.

1 comment:

Anonymous said...

Again, Peter, a thoughtful, well-balanced and insightful narrative. After having read numerous such entries, I'll opine that you'd probably do well as a journalist--say, the editor of a medical magazine. Cheers, Joe