Antioxidants may protect pilots from DNA damage
Ionising radiation is radiation from both natural and man-made sources which is energetic enough to create ions from atoms or molecules by removing an electron. At high altitudes, like those achieved by commercial jet airlines, ionising radiation increases because of exposure to significantly higher levels of cosmic radiation than at ground level.
According to the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), airline flight crew workers are exposed to higher average doses than any other worker, including those in nuclear power plants.
The detrimental effects of this radiation exposure include potential increased risk of DNA damage, which is considered an important trigger in cancer development, according to scientists from the US National Institutes of Health, the Harvard School of Public Health, and the American Cancer Society.
Writing in the American Journal of Clinical Nutrition, the researchers report that high intakes of a combination of vitamins C and E, beta-carotene, beta-cryptoxanthin, and lutein-zeaxanthin from food “may protect against cumulative DNA damage in ionizing radiation-exposed persons”.
Since antioxidants may protect against DNA damage, the US-based researchers estimated the dietary intakes of vitamins C and E and carotenoids in 82 male airline pilots using a food frequency questionnaire, and compared this to the frequency of chromosome translocations, used as a biological marker of cumulative DNA damage.
Above the average serving number of the vitamin C-rich fruit and vegetables was associated with a 39 per cent reduction in translocation frequency, while citrus fruit and green leafy vegetables were associated with 36 and 41 per cent reductions, respectively.
The strongest protective effects – a reduction of 73 per cent – were observed for above average combined intakes of vitamins C and E, beta-carotene, beta-cryptoxanthin, and lutein-zeaxanthin from food, said the researchers.
No cancer issues anyway
A recent review of the epidemiological evidence by scientists at the Johannes Gutenberg-University in Mainz, Germany reported that, despite “consistently elevated risks” for breast cancer amongst female aircrew members, and increased brain cancer among some pilots, overall cancer occurrence and mortality was lower than in the general population.
“Ionising radiation is considered to contribute little if at all to the elevated risks for cancers among aircrew, whereas excess ultraviolet radiation is a probable cause of the increased melanoma risk,” wrote the German reviewers in the journal Radiation Protection Dosimetry (doi:10.1093/rpd/ncp125).
Source: American Journal of Clinical Nutrition
Published online ahead of print, doi:10.3945/ajcn.2009.28207
“High dietary antioxidant intakes are associated with decreased chromosome translocation frequency in airline pilots”
Authors: L.C. Yong, M.R. Petersen, A.J. Sigurdson, L.A. Sampson, E.M. Ward