Carrots May Protect Against Lung Cancer

Some peeled carrotsCarrots are an extremely popular vegetable in the United States and are second only to potatoes in terms of consumption with an average of 12 pounds of carrots consumed per person per year. Carrots are well known for their ability to improve night vision however what is less known is that carrots and other foods rich in carotene may actually protect against lung cancer in both smokers and non-smokers.

One study, published in the journal Cancer Research in 1993, used data on 41,837 women from the Iowa Women’s Health Study to determine the effects of fruit and vegetable consumption on the risk of lung cancer. The researchers found that women in the top quartile for vegetable consumption were 50% less likely to develop lung cancer than women in the lowest quartile. Carrots in particular were associated with a 21% reduction in lung cancer while high consumption of green leafy vegetables reduced lung cancer risk by a massive 55%.

A second study, published in the International Journal of Epidemiology found that smokers who consumed carrots rarely or not at all were almost three times as likely to developing lung cancer as those who ate carrots more than once a week.

Finally, a study published in the Journal of the National Cancer Institute looked at the risk of lung cancer in non-smokers from New York state. That study found that a high intake of dietary beta-carotene reduced the risk of developing lung cancer by 30%.

Interestingly, while dietary beta carotene appears to reduce the risk of lung cancer, taking very high levels of beta carotene in the form of supplements appears to have no effect on lung cancer and in fact some studies have found an increased risk of lung cancer in smokers. One study, known as the Beta-Carotene and Retinol Efficacy Trial, had to be stopped early due to much higher than expected rates of lung cancer in the treatment group who were taking 30 mg of beta carotene per day and 25,000 IU of retinol.

Carotenes are natural pigments that are responsible for the bright orange and yellow colors of many fruits and vegetables. Alpha carotene and beta carotene are the two main forms of dietary carotene. Both are found in similar fruits and vegetables including sweet potatoes, carrots, pumpkin, broccoli, apricots, mangoes, and green leafy vegetables such as spinach, kale, watercress, and silverbeet.

Both alpha and beta carotene can be converted into vitamin A by the body when required. Vitamin A, in the form of retinol, can also be acquired through animal sources such as milk, cheese, butter and animal livers.