Specific micronutrients may reduce a process called methylation, which affects gene expression; this implies that a high intake of these micronutrients may reduce the risk of developing cancer.

Many genes involved in critical cell functions, including cell division, are methylated in lung tumours, meaning that they are effectively silenced. According to findings published online ahead of print in Cancer Research, a high intake of certain micronutrients may reduce the risk of lung cancer though a modulatory effect on gene methylation.

The researchers observed lower levels of gene methylation among users of multivitamin supplements rich in phytochemicals, such as vitamin C, carotenoids, lutein, folic acid, and vitamins A and K. Data was analysed from 1,100 current and former smokers. Saliva samples were collected to examine the degree of methylation of eight genes commonly silenced in lung cancer.

People who ate at least 12 servings of green leafy vegetables per month had a 17 per cent lower risk of methylation, while a daily folate intake of at least 750 micrograms was associated with a 16 per cent lower risk.

Current multivitamin users had a 43 per cent lower risk of gene methylation, added the researchers, although there was no association between the duration of use and methylation.

The use of multivitamin supplements by smokers is controversial, following findings that suggested that current smokers taking more than 30mg of beta-carotene were more likely to develop lung cancer. Commenting independently on the study, a spokesperson for ingredient supplier DSM told the online nutrition news station NutraIngredients that the study illustrates how complex micronutrient research is.

“It impressively shows, for example, that supplements containing beta-carotene, conceivably increasing the risk of lung cancer in heavy smokers when taken in extremely high doses over years, have the potential to reduce cancer risk even in smokers,” said the spokesperson.

“Additionally, the study is further evidence that nature-identical, synthetic micronutrients in multivitamins can be effective in disease risk reduction as micronutrients from vegetables and fruits.”

This research is preliminary but exciting; the relationship between micronutrients and the varied health benefits of the regular consumption of multinutrient formulas and fresh fruits and vegetables is only beginning to be understood.