Smoking out the dangers of COPD

By Dr. Keith Roach

I have been told that I have COPD. The lung doctor said that he's pleased with my X-ray and will see me next year. My concern is whether this will get worse. I'm scared to death. I have difficulty catching my breath. I quit smoking about four years ago. I know I can't repair the damage that has been done, but is there anything I can do to keep this disease from getting worse?

Chronic obstructive pulmonary disease in North America is due mostly to cigarette smoking, but cooking fires, asthma and other rare conditions also may predispose people to COPD.

Lung function decreases with aging in all adults, but in people with COPD -- a combination of emphysema and chronic bronchitis -- the worsening of lung function over time is critical because of the loss of pulmonary reserve.

You already have done by far the most important thing you can do to prevent further damage: quit smoking. Avoiding other air pollutants, especially secondhand smoke, also may help.

Regular physical activity seems to slow progression of COPD. Treatment with inhaled steroids reduces airway inflammation and somewhat slows progression of the decline in lung function in COPD.

Inhaled steroids also improve symptoms and reduce exacerbations. However, they do not have a significant effect on mortality.

X-rays are one way of following COPD, but measuring lung function through pulmonary-function tests is a much better way of determining severity of disease. Your lung specialist can give you more-personalized information about your illness with those results.

My question is: If a person eats a 2,000-calorie meal, how many calories, when digested, are absorbed by the body? I find it hard to believe that the body will absorb every single one of the 2,000 calories ingested. Please advise.

Our bodies are very well adapted to extract energy out of the food we eat, but you are right that there is some energy left in food at the time it is excreted. Some chemical energy also is used by the bacteria in the gut. A little bit is lost in the urine.

But, in general, we absorb probably 90 percent of the chemical energy stored in food. A few factors can affect that number.

Food that is cooked or processed tends to have calories that are more easily accessible and more absorbable. This may be one reason that those who eat only raw foods tend to lose weight; another may be that they avoid highly calorie-dense foods.

There also are medical conditions that prevent us from absorbing food properly -- lactose intolerance and celiac disease are two of the more common of the many causes of malabsorption. In summary, calorie counts are imprecise, but still useful for comparing one food with another.

Dr. Keith Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu. © 2018 North America Synd., Inc.