Teens Eat Poorly Now, May Breathe Worse Later

• A lack of fruit and fish in teenagers' diets may keep them from attaining full lung capacity and set them up for later respiratory problems.
• In a study, low fruit intake was associated with 1.3% lower lung function than predicted while low vitamin C intake was associated with the same degree of lung capacity impairment (both P≤0.05).
• Low intake of fruit, vitamin E, and n-3 fatty acid consumption was also linked to respiratory symptoms, including chronic bronchitis, wheezing and asthma.
• These relatively small effects were "not likely to have a functional impact on current respiratory health, but if these effects are being felt in the teen years when their lung function should be close to optimal levels, it's possible that they won't achieve their optimal levels and that the complaints of chronic bronchitis and wheeze may cause them to loose lung function by airway remodeling.
• “This "may have long-term consequences because lower pulmonary function in adults has been associated with increased morbidity and earlier mortality.
• Vitamin E intake in the lowest quantity below 5.2 mg per day was associated with an increased likelihood of reported asthma (11.6% versus 8.5%, adjusted OR 1.48, P≤0.05) compared with higher intake.

Intake of dietary n-3 fatty acids in daily vitamin C intake in the lowest quintile below 85 mg, although in the range of the IOM-recommended 65 to 90 mg per day, was associated with:

• Lower forced vital capacity (4.56 versus 4.61 L, difference -1.3%, 95% CI -2.4 to -0.02) compared with higher intake adjusted for calories.
• A trend toward lower FEV₁ (3.91 versus 3.95 L, difference -1.0%, 95% CI -2.2 to 0.1) compared with higher intake adjusted for calories.
• Higher odds of forced vital capacity less than 85% of predicted (odds ratio 1.63, 95% CI 1.05 to 2.50, P=0.03) compared with higher intake.

"This suggests the current daily recommended intake for vitamin C may not be adequate to protect lung function,"

Intake of dietary n-3 fatty acids in the lowest quintile below 22 mg was associated with:

• Chronic bronchitic symptoms (26.3% versus 20.0%, OR 1.37, P≤0.05).
• Wheeze (44.0% versus 37.0%, OR 1.34, P≤0.01).
• Asthma (12.7% versus 8.2%, OR 1.68, P≤0.01).

Teen smoking in combination with low antioxidant vitamin C intake showed even greater risk for respiratory symptoms.

The researchers also pointed out that an observational study "cannot establish the temporal relationship between diet and respiratory outcomes. It may be that the critical period for diet's effect on the respiratory system is during early childhood when there is rapid differentiation and growth."