Nutritional Defense against Pollution

In our modern world it is almost impossible to escape exposure to pollution, but the good news is that some researchers believe adequate levels of certain nutrients may offer some protection from these toxins. Supporting this belief is a study by Yale University researchers who recently found that asbestos-exposed workers with high dietary intakes of vitamin A had less pre-cancerous bronchial cell growth than those workers with low vitamin A intake.

In apparent contradiction of the Yale study, two previous studies had shown that vitamin A supplementation was associated with greater risk of lung cancer in smokers (smoke being a type of pollution). Researchers explain the different study outcomes by suggesting that dosage may be a critical factor. Moderate levels of vitamin A ingested from a vitamin A-rich diet protect against toxins, while high levels from supplementation could be somehow harmful. Another explanation is that dietary sources of vitamin A such as fruits and vegetables also contain a variety of other chemical substances that may reduce the risk of cancer.  Based on information in: American Journal of Clinical Nutrition, Vol 68 p 630 1998