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Welcome! Here we publish our views on new research and insights from the field of pulmonary medicine, most often focusing on topics related to exercise, nutrition, and other self-management techniques for those who suffer from chronic shortness of breath.

Whether you have COPD, currently smoke, or are just concerned about persistent shortness of breath and/or cough, read our articles to explore COPD treatment options and self-management techniques that can help you feel better NOW!



Friday, July 30, 2010

Pulmonary rehab effective in reducing overall COPD health care utilization

A revealing study published this month in the Kuwaiti journal Medical Principles and Practice showed significant health care utilization reductions for COPD patients who completed a pulmonary rehabilitation program.

The study was conducted in Saudi Arabia at the ONLY pulmonary rehabilitation clinic in the country. The results of the study echo similar results of studies conducted in other countries around the world – pulmonary rehabilitation consistently reduces subsequent emergency room visits, hospital stays, and length of hospital stays. Additionally, this study also demonstrated significant reductions in the use of antibiotics, steroids, and short-acting bronchodilator inhalers about the COPD patients who completed a pulmonary rehab program – a novel finding as depicted by the study author. (Al Moamary MS. Health care utilization among chronic obstructive pulmonary disease patients and effect of pulmonary rehabilitation. Med Princ Pract. 2010, 19(5):373-378, Epub 2010 Jul 14)

In this study, the research team looked retrospectively at the medical records of 50 COPD patients who were admitted to the King Abdulaziz Medical City Pulmonary Rehabilitation Center between 2004 and 2008. All of these patients had been initially admitted to the hospital for an acute exacerbation (a shortness of breath/coughing attack severe enough to require hospitalization) shortly immediately preceding enrollment into the rehab program. Of the 50 patients, 27 completed the pulmonary rehabilitation program (hereafter referred to as the compliant group) and 23 did not (noncompliant group).

The researchers sought to evaluate the differences between the compliant group and non-compliant group over the following 12 month period in terms of subsequent hospital visits/stays and prescription medication usage compared to the 12 months leading up to their entry into the pulmonary rehab program. The results were dramatically different between the two groups.

For example, the compliant group saw a 51% decrease in subsequent outpatient clinic visits, 60% decrease in emergency department visits, and a 72% drop in the length of hospital stays compared to their pre-pulmonary rehab experiences. By comparison, the non-compliant group visited outpatient clinics 14% more after bailing out of the pulmonary rehab program, visited emergency departments 14% more and experienced a mean increase in average hospital length of stay of 90%!

You could not paint a more convincing picture of the divergent experiences of COPD patients who pursue and complete pulmonary rehab programs versus those who don’t. These results are not novel – as mentioned above, previous studies around the globe have shown similar results (some more dramatic, others less dramatic – but the majority showing statistically significant differences in subsequent health care utilization). It makes you really scratch your head when you realize that even in the U.S. only 1-2% of COPD patients are ever admitted to a pulmonary rehab program. If there is a serious interest in reducing overall health care costs related to COPD (for both providers and patients), pulmonary rehab should become a standard treatment option for ALL COPD patients.

Separately, regarding subsequent usage of antibiotics, steroids, and short-acting bronchodilators, the Saudi Arabian study showed significant drops in reliance on these pharmacological agents in the compliant group compared to the non-compliant group.

Among the compliant group, short-acting bronchodilator use dropped 51%, antibiotic courses fell 53% and cumulative steroid dosage decreased by 31% compared to usage levels prior to entering and completing pulmonary rehabilitation. By comparison, the non-compliant group saw their usage of these three pharmacological options rise by 5%, 31% and 38% respectively. These are all significant differences and further reinforce the value of pulmonary rehabilitation.

As an aside, the researchers also reported that the compliant group saw their walking endurance rise 121 meters in the 6 minute walk test (a 54 meter rise is considered statistically significant by most researchers). Again, a clear indication of the power of pulmonary rehab.

The rehab program followed during the study was described the research team as follows, “1-hour session, 2–3 times per week over 8–12 weeks for a total of 18–24 sessions in an outpatient setting. The patients were discharged from the PR program at 8 weeks provided that they had completed 18 sessions or that they would complete 18 sessions within 8–12 weeks. The program consisted of exercises combining track or treadmill walking, upright cycling, stair stepping and arm ergometer. Direct small group education sessions were conducted by the PR physiotherapist. Both the exercise and education programs were carried out as previously described. The program provided exercise therapy consisting of combination treadmill or track walking, upright cycling, stair stepping and arm ergometer. The intensity of the exercises was individualized based on the patient’s tolerance, physiological parameters and PR physiotherapist judgment. Aerobic exercises comprised upper extremity, lower extremity, flexibility and strength. The educational component included modules covering obstructive and restrictive lung diseases, breath retraining, pulmonary hygiene, dietary modification, risk factor modification, pulmonary medications and equipment, stress management/relaxation, smoking cessation advice, exercise benefits, musculoskeletal injury prevention and overall pulmonary disease intervention.”

As regular readers of our e-letters and blog are well aware, we are strong proponents of pulmonary rehabilitation for COPD patients (and anyone else who suffers from chronic shortness of breath). If you can gain entry to a program in your area, we highly endorse participating in the program. If you can’t gain entry, there are still many aspects of pulmonary rehab you can practice at home or in a fitness center. We created our Breathe Better for Life guide and CD-ROM to assist COPD patients and others who suffer from persistent breathlessness with the resources to start such an at-home or fitness center based program (in consultation with your personal physician of course). Our program is based on guidelines established by the American Thoracic Society, European Respiratory Society, and the American College of Sports Medicine and has been reviewed and edited by prominent respiratory care professionals. To order Breathe Better for Life, visit www.breathebetterforlife.com.

Monday, July 26, 2010

COPD and walking abnormalities

Muscular dysfunction is a common symptom of COPD patients and is most often related to lack of physical activity. People who suffer from chronic shortness of breath tend to limit physical activity in order to avoid dyspnea events (shortness of breath episodes). The downside of limiting physical activity for an extended period of time is that as a person becomes more sedentary, the body loses its cardiovascular and muscular conditioning. This in turn results in persistent fatigue, greater dyspnea events and creates a vicious cycle of physical de-conditioning. One way this de-conditioning is evidenced is through walking gait abnormalities such as limping and shuffling as muscle fibers change/weaken from lack of use.

A new study published this month online ahead of print examined the association between walking abnormalities and COPD and determined there is a direct correlation between the presence of walking abnormalities and severity of COPD. (Yentes J, et al. Walking abnormalities are associated with COPD: An investigation of the NHANES III dataset. Respiratory Medicine. 2010 Jul 6. Epub ahead of print)

According to the study authors, while other research studies have examined the connection between COPD severity/physical activity level related to respiratory function, muscle strength, and cardiovascular conditioning, this is the first study to examine the association between COPD severity and walking gait abnormalities. As the researchers explained, “There is evidence that lack of physical activity contributes to peripheral muscle abnormalities and dysfunction.

Disuse of the muscular system can result in muscular atrophy, decreased muscle strength, increased muscle fatigability, reduced oxidative capacity, and capillary loss…These muscular impairments may also lead to abnormal walking patterns; however this has not previously been tested in COPD.”

In their study, the researchers sampled medical records of approximately 8,400 U.S. adults from the NHANES III database. The NHANES III database contains the medical records of over 31,000 U.S. adults who agreed to be examined and surveyed between 1988 and 1994 and is sampled in a wide range of medical research.

The 8,400 patient records were selected based on criteria established by the research team, including age, walking status, and respiratory function measures. Once selected, the research team then examined the statistical relationship between COPD severity and walking gait abnormalities (defined in the study as either a chronic limp or shuffle). They determined that severe COPD patients had almost 2 times the odds of a walking gait abnormality compared to those with mild or moderate COPD (there was not a statistically significant difference between mild and moderate COPD patients).

They researchers concluded, “The novel finding is that COPD is related to walking abnormalities. When using a comprehensive classification scheme for COPD status, a significant association between severe COPD status and walking abnormalities was observed. From clinical point of view, reduced physical activity in daily life and impaired muscle strength are the most likely causes. This was confirmed as demonstrated by decreased physical activity being significantly associated will all levels of COPD severity. These results strengthen the novel findings by demonstrating the importance of physical activity and the effect of inactivity on walking abnormalities.”

We wholeheartedly agree with this last statement. Research study after research study has shown that physical activity/exercise in COPD patients actually reduces fatigue and shortness of breath events in addition to building cardiovascular function, stronger muscle fibers, and higher quality of life. These are the primary goals behind the treatment option known as pulmonary rehabilitation and are the basis of our exercise recommendations in the Breathe Better for Life guidebook, www.breathebetterforlife.com.

While the study authors do not suggest that COPD patients who have walking gait abnormalities may see the abnormalities diminished or eliminated by engaging in regular physical activity/exercise, they do suggest that there is likely a correlation between inactivity and the development of walking abnormalities.

Whether regular physical activity/exercise can reverse a walking gait abnormality or not, the other benefits gained by COPD patients from regular physical activity/exercise are unambiguous. As the study authors offered, “…studies have demonstrated positive effects of exercise training on COPD patients. These positive effects include increased muscular size, strength, power, endurance, mitochondrial capacity, and restoration of protein levels.”

Wednesday, July 21, 2010

29% of people with persistent cough undetected for COPD in new study

One of the greatest challenges facing pulmonology professionals worldwide is under-diagnosis of COPD. In fact, many researchers estimate that the number of worldwide undiagnosed COPD cases are equivalent to diagnosed COPD cases - meaning for every one person with a COPD diagnosis there is one additional person who has COPD but is unaware they have the condition. That’s astounding when you consider that in the U.S. alone, there are over 13 million people who’ve already been diagnosed with COPD. There are a variety of reasons why the under-diagnosis dilemma exists.

First, many people who have COPD-like symptoms (e.g. recurrent bouts of persistent cough, heavy sputum, breathlessness) don’t go to see their doctor unless and until they have an exacerbation event (a term meaning a shortness of breath attack severe enough to require an emergency room visit and/or hospital stay). For example, we wrote about a UK study in April 2010 that showed 34% of people admitted for a first-time exacerbation event to UK hospitals participating in the study were previously undiagnosed for COPD. Of these people, 57% already had severe COPD before they were diagnosed. To read more about that study, click here.

Second, many people who do seek out a doctor’s evaluation tend to first visit their general practitioner. Many general practitioners address the COPD-like symptoms with a combination of antibiotics (to reduce sputum and persistent cough), bronchodilator inhalers (to temporarily open up airways and relieve acute breathlessness), and smoking cessation counseling. These are all reasonable treatment solutions to address the patient’s immediate symptoms but often times this is where the general practitioner stops. They do not often administer spirometry tests (one of the few diagnostic tests available to identify whether COPD is indicated) and do not often refer patients to pulmonologists for lung function testing.

By way of illustration, this month a Dutch team of researchers reported their findings of a 3 year study looking at undetected cases of COPD among 353 Dutch citizens who visited 73 general practitioners between 2006 and 2009 complaining of persistent cough. They found that 29% of the study participants (39% of men and 21% of women) over the age of 50 who visited their GP for persistent cough lasting 14 days or more had undetected COPD. In addition, 7% of men and women evaluated during the study were found to have undetected asthma. (Broekhuizen B, et al. Undetected chronic obstructive pulmonary disease and asthma in people over 50 years with persistent cough. British Journal of General Practice. 2010; 60:489-494)

Further, in a Canadian study we wrote about in our above mentioned April 2010 article, nearly 67% of people visiting their GP reporting one or more respiratory symptoms were unaware they had COPD and were not diagnosed by the GP during his/her evaluation.

Third, when people do receive spirometry (whether from a pulmonologist or a GP), the results of the tests are often either interpreted incorrectly or do not indicate the presence of COPD (even though other respiratory symptoms indicate COPD). In March 2010, we reported the findings of a Swedish study that showed that nearly 70% of patients in their study had initial spirometry tests that did not confirm a diagnosis of COPD. To read more about this study, click here.

This combination of factors means that tens of millions of people worldwide do not receive access to the full range of treatment options for COPD early in the development of their condition. As a result, when COPD is finally diagnosed, most “previously undiagnosed” patients are already considered moderate to severe (in the Canadian study mentioned above, 21% of the people who were finally diagnosed with COPD after their GP did not detect COPD actually were later confirmed with severe COPD).

As we’ve counseled before – if you suspect that shortness of breath, persistent cough or an increase in sputum secretion is increasingly affecting your ability to participate in everyday activities you owe it to yourself to see your doctor ASAP. Yes, you’ll probably have to undergo some tests and you will likely hear an earful about stopping smoking, exercising more and/or changing your dietary habits (all excellent recommendations for making an immediate impact on your shortness of breath). You’ll also likely receive a prescription for a prescription inhaler such as Spiriva, Advair or Combivent and you may be prescribed antibiotics.

When you visit your doctor, ask for a referral to a local pulmonologist and in turn ask the pulmonologist to order a spirometry test. You are far more apt to get a correct diagnosis by seeking an evaluation from a qualified pulmonologist trained to administer and interpret spirometry results than through any other means. In the end , you have a far better chance of limiting the ravaging effects of severe lung disease by seeking treatment sooner rather than later – even if some of the prescribed solutions mean altering your long practiced habits.

If you are unfamiliar with the treatment options available for COPD, we have detailed the full range of treatment options in our Breathe Better for Life guide and companion CD-ROM. We developed the guide and CD to provide people who suffer from chronic shortness of breath with self-management strategies for reducing shortness of breath, improving physical conditioning, and improving overall quality of life (whether you have COPD already or you are a current/former smoker and you'd simply like to breathe & feel better). However, our guide and CD describe the full range of COPD treatment options including pictorial demonstrations. To purchase the guide and CD, visit www.breathebetterforlife.com.

Sunday, July 18, 2010

Depression, smoking and exercise

In April 2010, the U.S. National Center for Health Statistics (NCHS) published a report detailing their findings about the association between depression and smoking. The report showed that 43% of Americans who report being depressed are current smokers. The report further demonstrated that depression was most severe in the heaviest of smokers. (Pratt LA, Brody, DJ. Depression and Smoking in the U.S. Household Population Aged 20 and Over, 2005-2008. NCHS Data Brief. 2010 April; (34)1-8).

Overall, depression among adults over the age of 20 is only reported by 7% of the total U.S. adult population, but that still represents over 15 million people. By comparison, the total number of confirmed COPD cases in the U.S. is around 13 million people so depression is clearly a significant societal issue.

The NCHS-reported 43% depression rate among current smokers implies that approximately 6.5 million of the 15 million people in our country suffering from depression are current smokers. Since there are approximately 43 million current smokers in the U.S., the 6.5 million smokers reporting depression represent about 15% of total current U.S. adult smokers.

Among the other significant findings reported by NCHS is the fact that 51% of smokers who light up their first cigarette of the day within 5 minutes of waking up report depression. By contrast, only 23% of smokers who waited over 30 minutes before consuming their first cigarette of the day reported depression. In addition, those who smoked the most (2 packs a day or more) reported the most severe depressive symptoms.

The report authors speculate that current smokers’ depression is largely related to frustration about the inability to quit smoking. We agree with that speculation and would further add concern/frustration among smokers about other elements of their health status (poor diet, breathlessness, and other conditions such as hypertension, heart disease and diabetes).

Is there a way out for smokers who are clinically depressed?

Most doctors will focus first and foremost on recommending smoking cessation. However, as most smokers who’ve attempted to quit in the past (successfully or unsuccessfully) can attest – it is excruciatingly difficult to do. A slew of research continues to search for aids to help improve smoking cessation success but thus far the “successful” results are modest at best. Though smoking cessation statistics vary by source quoted, it is safe to say that of the 43 million current smokers in our country, approximately 70% report a desire to quit each year, 35-40% actually try in a given year, and about 5-15% of the people who try are successful in abstaining for more than 1 year.

A common treatment option for depressive symptoms among smokers is to prescribe anti-depressant drugs such as Chantix. While these drugs taken alone, or combined with nicotine replacement can boost cessation success rates, they also have scary potential side effects.

But if you’re in a situation where you either have tried to stop smoking and can’t, or you are just not ready to try quitting, what do you do?

We think it is worth considering exercise. Now, you may chuckle at this suggestion but there have been a number of studies showing exercise’s benefits for smokers in the following ways:

- Slowing the progression of lung disease (click here to read more)
- Improving physical conditioning, reducing shortness of breath, and Improving sense of well being/quality of life (click here to read more)
- Enhancing smoking cessation success rates (click here to read more)
- Reducing the incidence of lung cancer (click here to read more)

In addition, there is evidence that exercise among people who exhibit depressive symptoms does modestly improve sense of well being though this review of depression/exercise studies does not specifically evaluate depression among smokers. (Mead GE, et al. Exercise for depression. Cochrane Database Syst Rev. 2009 Jul 8;(3):CD004366)

We’re not saying exercise will cure depression but we think it may help. Specifically, we are saying that if your depression stems from frustration that you can’t seem to quit smoking and you’re not ready to try again right now, there is a viable option to consider beyond prescription anti-depressants (exercise). Further, we are saying that there is evidence that improving your physical conditioning prior to smoking cessation or in conjunction with smoking cessation can boost success rates (ala the links to other articles we’ve written on these topics).

It also makes intuitive sense to us – if you’re in a position where you feel you are not in control of your health (i.e. you want to quit smoking but can’t seem to do it), taking any positive steps to improve your health improves your sense of well being. Improving your sense of well being sounds like relieving depression to us, and if exercise can improve your physical conditioning and sense of well being, it’s quite possible that it will be easier for you to consider stopping smoking.

If you want to begin an exercise program, where do you start? Well, the most likely concern about beginning an exercise program if you are a current smoker is the high likelihood you will experience an uncomfortable degree of breathlessness. That’s where the principles of pulmonary rehabilitation come into play. Exercise programs in pulmonary rehab are specifically designed to help people who suffer from chronic shortness of breath start out at a manageable level and then increase the intensity and duration of exercise over time in an effort to lessen the likelihood and severity of shortness of breath attacks (known as dyspnea). For most smokers though, gaining entry to a pulmonary rehab program without completing a smoking cessation program first is almost unheard of. There is a strong bias against offering current smokers entry even though physicians agree smokers can significantly benefit from this valuable treatment option (a chicken and egg problem of modern pulmonary medicine).

That is one of the reasons why we developed the Breathe Better for Life guidebook and companion CD-ROM. We scoured the research, visited pulmonary rehab centers, and consulted leading respiratory care professionals to construct an at-home or fitness center based exercise program for people who suffer from chronic shortness of breath (whether you quit smoking first or not). To learn more about purchasing Breathe Better for Life, visit www.breathebetterforlife.com.

Whether you consider our exercise program in consultation with your physician, or begin one recommended by your physician, it is highly worth your time to give exercise a shot. There is so much health benefit upside for current smokers from an active, ongoing exercise program and in our opinion, it may make a significant difference about how you feel about yourself, your prospects, and ultimately your ability to stop smoking.

Wednesday, July 14, 2010

N-acetyl-cysteine reduces airway inflammation caused by cigarette smoke

A new study published in the Chinese Medical Journal demonstrated the effectiveness of the powerful antioxidant, N-acetyl-cysteine (commonly referred to as NAC), in reducing airway inflammation in rats exposed to cigarette smoke.

Buyers of our Breathe Better for Life guidebook and readers of our e-letters and blog know we are a strong proponent of NAC for its effectiveness in boosting exercise tolerance among COPD patients undergoing pulmonary rehabilitation (click here to read more) and its previously studied ability to reduce COPD exacerbations.

To begin, NAC is an amino acid that stimulates the body’s production of glutathione. According to the Chinese Medical Journal study authors, “glutathione (GSH) appears to be an important antioxidant in the lungs and is present in high concentrations in epithelial lining fluid [the epithelium is the smooth coating/lining of the bronchioles in the lungs]”. Glutathione is not particularly absorbed well by the body in nutritional supplement form and so researchers tend to utilize NAC since it stimulates the body’s own production of GSH. That said GSH is absorbed well by the body in foods such as asparagus, avocado, cabbage, broccoli, brussels sprouts, walnuts, dill seeds, caraway seeds, and some cooked fish.

Previous studies have shown that cigarette smoke exposure reduces GSH levels in epithelial tissue and damages the epithelial lining. A number of researchers have speculated that these two events are related but no one to date has definitively proved the connection.

In this study, the research team focused on a particular type of cell that is highly present in the epithelial lining called a Clara cell. These cells secrete a protein known as CC16 that is believed to be a protective agent against inflammation and infection. According to the study authors, previous studies have shown that in COPD patients and smokers that Clara cell and CC16 levels are decreased compared to healthy epithelial tissue.

So the researchers set out to determine whether laboratory rats exposed to cigarette smoke experienced a drop in Clara cells and CC16 protein and a corresponding increase in airway inflammation. Further, the researchers wanted to know whether oral supplementation of NAC would increase the number of Clara cells and CC16 protein and, by virtue of these increases, reduce airway inflammation. (Liao J, et al. Effects of N-acetyl-cysteine on Clara cells in rats with cigarette smoke exposure. Chin Med J 2010; 123(4):412-417)

The 18 laboratory rats in the study were divided into three groups. Group 1 (the Control Group) received no cigarette smoke exposure and no NAC supplementation. Group 2 (Cigarette Group) received exposure to cigarette smoke from 10 cigarettes 3 times a day for 30 minutes over the course of 1 week but no supplemental NAC. Group 3 (NAC Group) was exposed to an equal dose of cigarette smoke as Group 2 but also received 80mg of NAC per kilogram of body weight each day they were exposed to cigarette smoke.

Even though the study lasted only one week, the rats in the Cigarette Group had a 33% lower count of Clara cells and a 50% lower count of CC16 protein molecules in respiratory epithelial lining tissue compared to the Control Group. According to the research team, the Cigarette Group also had a 164% higher count of observed small airways in lung tissue samples examined under microscope compared to the Control Group (their measure of airway inflammation).

While the NAC Group also had lower counts of Clara cells and CC16 protein compared to the Control Group, the gaps in counts were significantly lower than the Cigarette Group. Clara cells in the NAC Group were 22% lower than the Control Group (as opposed to 33% lower for the Cigarette Group). CC16 protein counts were 33% lower (compared to 50% lower in the Cigarette Group), and the number of small airways observed under microscope for the NAC group was only 24% higher than the Control Group (versus 164% higher in the Cigarette Group).

So it appears that while NAC was not successful in this study in completely offsetting the impact of cigarette exposure it did significantly lessen the impact of cigarette smoke on Clara cell count, CC16 protein count, and on the number of small airways present in observed in the rat lung tissue samples.

This study utilized 80mg/kg of laboratory rat body weight but there is no guidance offered by the researchers for what an appropriate human dosage level would be to achieve similar results. Previous human studies on NAC for COPD patients have examined daily dosage levels of 300mg, 600mg, and 1200mg though there is no consensus/standard recommendation regarding human dosage levels for reducing airway inflammation. The recent study regarding NAC’s effectiveness in improving exercise tolerance we mentioned above utilized a daily dosage of 1200mg. Among our other nutritional supplement recommendations for people who suffer from chronic shortness of breath, our Breathe Better for Life guidebook recommends 300-600mg of NAC once or twice daily based on the previously published research studies we’ve reviewed.

NAC is widely available as a nutritional supplement online and in retail stores in 300mg and 600mg dosage levels for $10-$30 for a 30 day supply depending on dosage level chosen. Please consult your physician if you intend to try NAC to ensure it is an appropriate nutrient for your particular situation (i.e. there is a known counter-indication for people who take nitroglycerin and your physician may be aware of others).

Saturday, July 3, 2010

Four foods associated with lower risk of developing COPD

Of the research studies published over the past two years regarding foods that are associated with reduced risk of developing COPD, there are four foods in particular that have been studied multiple times with similar results over a number of years. Most likely the list will not surprise you as all four food items are commonly viewed as good additions to the average person’s daily diet. However, these foods have been specifically recently studied in relationship to COPD risk:

1. Dietary fiber – an April 2010 study published in the Journal of Epidemiology showed that U.S. men and women whose diet contained higher fiber content from fruits, vegetables, and particularly cereal fiber had notably lower new COPD diagnoses compared to those with low dietary fiber intake. (Varraso R, et al. Prospective study of dietary fiber and risk of chronic obstructive pulmonary disease among US women and men. Am J Epidemiol. 2010 Apr 1; 71(7):776-84. Epub 2010 Feb 19)

2. Soy (isoflavones such as tofu and bean sprouts) – a January 2010 Japanese study examining dietary differences between study participants with COPD and participants with healthy lung function showed that low soy consumption was significantly correlated with COPD diagnosis and degree of breathlessness (meaning those participants who consumed the least soy were more likely to be diagnosed with COPD and experience notably worse breathlessness). (Hirayama F, et al. Dietary intake of isoflavones and polyunsaturated fatty acids associated with lung function, breathlessness and the prevalence of chronic obstructive pulmonary disease: Possible protective effect of traditional Japanese diet. Mol Nutr Food Res. 2010 Jan 28. [Epub ahead of print])

3. Fish (Omega-3 and Omega-6 fatty acids) – the same January 2010 Japanese study also examined participants’ intake of fish, a main staple of the Japanese diet. Much like the results for soy, the researchers found, “High intakes of PUFA (polyunsaturated fatty acids) and omega-6 fatty acids (derived from foods excluding oils and fats as seasonings) also appeared to reduce the risks of COPD and breathlessness symptoms”.

4. Vegetables with high Vitamin A content (carrots, sweet potatoes, broccoli, peas, spinach) – a separate Japanese study published online in June 2009 examined the dietary consumption of fruits and vegetables among COPD participants and otherwise healthy adults in the study and discovered that people who consumed the highest levels of vegetables had the lowest risk of developing COPD. Further, the most pronounced benefit was provided by consuming vegetables high in Vitamin A (those who consumed the highest amounts of Vitamin A had a 52% lower risk of developing COPD versus those with the lowest levels of Vitamin A). Interestingly, there did not appear to be a strong correlation between fruit consumption and reduced COPD risk (Hirayama F, et al. Do vegetables and fruits reduce the risk of chronic obstructive pulmonary disease? A case-control study in Japan. Prev Med. 2009 Aug-Sep; 49(2-3):184-9. Epub 2009 Jun 23)