hole food diets containing high intakes of fruit, vegetables and whole grain cereals are beneficial to the health by protecting from major disease. This may be because of the antioxidants that plant foods contain, many of which are bioavailable in humans and act as in vivo free radical scavengers. High antioxidant plant foods are common to many of the healthy diets in the World including the Mediterranean diet. Epidemiological data suggests that predominately plant based diets high in antioxidants may be beneficial at preventing lung dysfunction. In particular, studies show an inverse associations between fruit and vegetable intake and the prevalence of asthma. Mechanistically, this may result from quenching of free radicals that are associated with airway smooth muscle contraction. However, antioxidants are not just protective of asthma, but may be useful therapy for a range of conditions that cause lung function deterioration.
As well as epidemiological evidence, clinical studies have also shown benefits to high antioxidant diets in the treatment of the clinical symptoms of asthma. For example, in one study subjects received either a high antioxidant diet consisting of 5 servings of vegetables and 2 servings of fruit per day, or a low antioxidant diet consisting of less than 2 servings of vegetables and 1 serving of fruit per day. The subjects followed the diet for two weeks before swapping to a diet supplemented with a placebo (for the high antioxidant group), or a 14 mg per day of lycopene extract (for the low antioxidant group). After 14 days the low antioxidant diet group had poorer lung function (measured as forced expiratory volume) when compared to the high antioxidant diet. However, no significant difference existed between the two groups from day 14 to 28.
Therefore a whole food diet high in antioxidants may be beneficial at improving asthma. This may result because of the quenching of free radicals in lung tissue, thus improving lung function. However, this effect does not appear to be replicated with the supplementation of 14 mg per day of lycopene. This may be because a whole food diet provides a larger quantity of total antioxidants than present in the lycopene. It could be because the beneficial antioxidants are not carotenoids but some other plant phytonutrient. It could also be because a whole food diet provides a range of antioxidants of different classes that act synergistically to provide a higher level of total protection. These results therefore support other research that shows that whole foods provide better antioxidant protection from disease than using single supplements in high concentrations. The drug industry should take note.
RdB
