Monthly Archives: July 2012

Mediterranean Diet Improves Asthma

Posted on July 4, 2012 | 2 comments

Researchers in Portugal found that high adherence to the Mediterranean diet reduced by 78% the risk of out-of-control asthma.

Other recent studies have associated the Mediterranean diet with 1) lesser incidence of asthma-like symptoms and allergies in children of women who followed the Mediterranean diet while pregnant, and 2) reduced risk of chronic obstructive pulmonary disease in men who eat Mediterranean-style.

The Mediterranean diet is famous for prolonging life and reducing rates of cardiovascular disease, cancer, and dementia.  Type 2 diabetes mellitus was recently added to the list of diseases prevented by the Mediterranean diet.  We have to consider adding lung disease to the list next.

In my capacity as a hospitalist, I see lots of poorly-controlled asthmatics.  The standard therapeutic approach is avoidance of allergens when possible, and administration of multiple drugs with multiple potential adverse effects.  So the following study involving diet and asthma caught my eye.

Scientists in Portugal studied 174 asthmatics with an average age of 40.  They administered an Asthma Control Questionnaire and measured lung function and exhaled nitric oxide.  Food intake was determined with a food frequency questionnaire, and a diet score was used to determine conformity to the Mediterranean diet.

Asthmatics felt to be under good control comprised 23% of the participants.  Were there dietary factors associated with good control?

I’m glad you asked.  The answer is , “Yes”:

  • high adherence to the Mediterranean diet
  • higher intake of fresh fruit
  • lower intake of ethanol (alcohol)

The researchers note that “the traditional Mediterranean diet is claimed to possess antioxidant and immune-regulatory properties in several chonic diseases.  Typical Mediterranean foods have recently been associated with improvement of symptoms of asthma and rhinitis [runny nose, often allergy-related] in children” in Crete and Spain.

This study is good news for people with asthma.  But association of well-controlled asthma with the Mediterranean diet does not prove that the diet is causing the improvement.  Next, we need a study that educates people with asthma on the Mediterranean diet, monitors adherence, and follows them over time while checking for improvement in asthma and comparing to a control group on a standard diet.

Steve Parker, M.D.

Reference:  Barros, R., et al.  Adherence to the Mediterranean diet and fresh fruit intake are associated with improved asthma control.  Allergy, vol. 63 (2008): 917-923.

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Posted in Lungs

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Does Food Affect Lung Disease?

Posted on July 3, 2012 | 1 comment

In another blog post, I provided evidence that diet may indeed affect lung function and disease, specifically asthma.  Another common lung condition is chronic obstructive pulmonary disease (COPD), which includes chronic bronchitis and emphysema.  COPD is usually associated with smoking.

By the way, a couple years ago “chronic lower respiratory tract disease” finally surpassed stroke to become the third leading cause of death in the U.S.  These lung diseases are mostly emphysema, COPD, and asthma.

In 2007, scientists with the Harvard School of Public Health, Harvard Medical School, and Simmons College concluded that “in men, a diet rich in fruits, vegetables, and fish may reduce the risk of COPD whereas a diet rich in refined grains, cured and red meats, desserts and French fries may increase the risk of COPD.”

The Boston, MA, researchers included academic heavyweights such as Teresa Fung, Walter Willett, and Frank Hu.  They studied 42,917 men in the Health Professionals Follow-up Study via detailed periodic questionnaires.  The men at baseline had never had asthma or COPD.  Onset of COPD between  1986 and 1998 was evaluated by questionnaire and was defined as an “affirmative response to physician-diagnosed chronic bronchitis or emphysema and by the report of a diagnostic test at diagnosis (pulmonary function testing, chest [x-ray] or chest CT scanning).”  Participants reported 111 new cases of COPD.

Investigators identified two distinct major dietary patterns at baseline:

  1. “Prudent” pattern:  high intake of vegetables, fruits, fish, poultry and whole grains.
  2. “Western” pattern:  high consumption of cured and red meats, refined grains, desserts and sweets, French fries, eggs and high-fat dairy products.

The prudent dietary pattern was inversely associatied with the risk of newly diagnosed COPD, regardless of smoking status.  In other words, the higher an individual’s conformity to the prudent pattern, the lower the risk of new COPD.

On the other hand, the Western pattern was positively associated with the risk of newly diagnosed COPD, again regardless of smoking status.

They did not note any association between either dietary pattern and the risk of developing asthma.

Clearly, there are similarities between the prudent dietary pattern and the traditional Mediterranean diet.  The main differences are that the Mediterranean diet includes significant amounts of olive oil, limited red meat and eggs, and judicious amounts of wine.  The Mediterranean diet incorporates the prudent pattern.  But the Mediterranean diet is not the “prudent dietary pattern” studied at Harvard.  Whether the Mediterranean diet would match or supercede the prudent diet in prevention of COPD is a matter of speculation.  The smart money would bet in favor of the Mediterranean diet reducing rates of COPD to at least some degree.

In view of a study associating improved asthma control with the Mediterranean diet, you gotta wonder if the researchers would have confirmed it, if they had been looking.  Are there substances in olive oil, or other aspects of the Mediterranean diet, that  improve lung function?

Many people are aware that dietary patterns have an effect on heart disease, overweight and obesity, high blood pressure, diabetes, dementia, cancer, and strokes.  We can add chronic lung disease to the list now.

Steve Parker, M.D.

Reference:  Varraso, Raphaelle, et al.  Prospective study of dietary patterns and chronic obstructive pulmonary disease among US men.  Thorax, vol. 62, (2007): 786-791.

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Evidence In Favor of Healthfulness of Whole Grains

Posted on July 2, 2012 | 3 comments

I bought a sack of potatoes the other day.  The advertising on the sack proclaimed   these potatoes as “Gluten-Free!”.  As if other potatoes have gluten (they don’t).

In these days of gluten-free this and gluten-free that, the health benefits of grains—especially wheat—are being questioned.

A 2008 review article in a scientific journal confirmed the association between high whole grain intake and reduced incidence of cardiovascular disease.  Heart disease and strokes (subsets of cardiovascular disease) are the first and fourth leading causes of death, respectively, in the U.S.

The article authors, Philip Mellen, Thomas Walsh, and David Herrington, reviewed the scientific literature on the subject and found seven pertinent published observational studies.  Study participants were divided into those with high average whole grain intake (2.5 servings per day) and those with low average intake (0.2 servings a day, or 1 serving every 5 days).  Compared with low intake, participants with high intake had 21% lower risk of cardiovascular disease events, such as heart disease, stroke, and death from cardiovascular disease.

Refined grain intake, such as standard white bread, was not associated with cardiovascular disease one way or the other.

The authors conclude, “There is a consistent, inverse association between dietary whole grains and incident cardiovascular disease…and clinicians should redouble efforts to incorporate clear messages on the beneficial effects of whole grains into public health and clinical practice endeavors.”

I’ll be the first to admit that observational studies don’t prove that whole grains reduce the risk of cardiovascular disease.  They identify an association that should lead to additional testing of the hypothesis.  I don’t see any proof on the foreseeable horizon.

If heart attacks and strokes ran in my blood lines (genes), I’d try to incorporate two or three daily servings of whole grain into my diet, assuming I had no good reasons to avoid grains.

That being said, I’m also convinced that many can live long health lives without grains.

Steve Parker, M.D.

References and resources:

Mellen, Philip, et al.  Whole grain intake and cardiovascular disease: A meta-analysis.  Nutrition, Metabolism & Cardiovascular Diseases, 18, (2008): 283-290.

The Whole Grains Council.  Learn more about the benefits of various whole grains and how to find whole grain products.  Many recipes here, plus links to hundreds of recipes at other websites.

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Posted in Coronary Heart Disease, Heart Disease, Stroke

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Adverse Health Effects of Obesity

Posted on July 1, 2012 | Comments Off on Adverse Health Effects of Obesity

As a physician, I see many illnesses and conditions that are caused or aggravated by overweight and obesity.  Both terms refer to excess body fat; obesity is a greater degree of fat.

Body mass index (BMI) is used to define overweight and obesity.  Your BMI is your weight in kilograms divided by your height in meters squared.  A BMI between 18.5 and 25 is considered healthy.  BMIs between 25 and 30 are overweight.  Here’s an online BMI calculator.  For example, a 5-foot, 4-inch person enters obesity territory – BMI over 30 – when weight reaches 174 pounds (79 kilograms).  A 5-foot, 10-incher is obese starting at 208 pounds (94.5 kilograms).

People trying to lose excess fat typically have days when willpower, discipline, and commitment waver.  On those days, it can help to remember why they started this adventure in the first place.  The reasons for many involve improved health and longevity.  Even if you have just 20 pounds of excess fat to lose, it will often take twenty weeks.  Your weight-loss goal is one to one-and-a-half pounds a week.  This race is won not by the swift, but by the slow and steady.

Here’s a laundry list of obesity-related conditions to remind you why you want to avoid obesity:

  • Premature death.  It starts at BMI of 30, with a major increase in premature death at BMI over 40.  The U.S. has 200,000 yearly deaths directly attributable to obesity.
  • Arthritis, especially of the knees.
  • Type 2 diabetes melllitus.  Eight-five percent of people with type 2 diabetes are overweight.
  • Increased cardiovascular disease risk, especially with an apple-shaped fat distribution as compared to pear-shaped.  Cardiovascular disease includes heart attacks, high blood pressure, strokes, and peripheral arterial disease (poor circulation).
  • Obstructive sleep apnea.
  • Gallstones are three or four times more common in the obese.
  • High blood pressure.  At least one third of cases are caused by excess body fat.  Every 20 pounds of excess fat raises blood pressure 2-3 points (mmHg).
  • Tendency to higher total and LDL cholesterol, higher triglycerides, while lowering HDL cholesterol.  These lipid changes are associated with hardening of the arteries – atherosclerosis – which can lead to heart attacks, strokes, and peripheral arterial disease.
  • Increased cancers.  Prostate and colorectal in men.  Endometrial, gallbladder, cervix, ovary, and breast in women.  Kidney and esophageal adenocarcinoma in both sexes.  Excess fat contributes to 14-20% of all cancer -related deaths in the U.S.  Over 550,000 people die from cancer in the U.S. yearly.  Twenty percent of us will die from cancer.
  • Strokes.
  • Low back pain.
  • Gout.
  • Varicose veins.
  • Hemorrhoids.
  • Blood clots in legs and lungs.
  • Surgery complications: poor wound healing, blood clots, wound infection, breathing problems.
  • Pregnancy complications: toxemia, high blood pressure, diabetes, prolonged labor, greater need for C-section.
  • Fat build-up in liver.
  • Asthma.
  • Low sperm counts.
  • Decreased fertility.
  • Delayed or missed diagnosis due to difficult physical examination or weight exceeding the limit of diagnostic equipment.

I hope you find this information motivational rather than depressing.  For those already obese, weight loss can significantly improve, alleviate, or prevent these conditions.  Many obesity-related medical conditions and metabolic abnormalities are improved with loss of just five or 10% of total body weight.  For instance, a 240 pound man with mild diabetes and high blood pressure may be able to reduce or avoid drug therapy by losing just 12 to 24 pounds.  He’s still obese, but healthier.

Steve Parker, M.D. 

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Posted in Overweight & Obesity