Regular intake of the antioxidant carotenoid lycopene, from good food sources like tomatoes and processed tomato products, has been associated with a lower incidence of certain types of cancers – especially prostate cancer, pancreatic cancer, lung cancer, skin cancer, and cancers of the digestive tract – but many other types are being studied and the protective mechanisms are often similar.
Ahead are some of the more interesting studies I’ve found on lycopene cancer research.
Lycopene and Prostate Cancer
In a study at Harvard University of almost 48,000 men it was found that those who ate more than two servings of tomato sauce a week were up to 36% less likely to be diagnosed with prostate cancer than those who consumed less than one serving of tomato sauce a month over a 12 year period (Journal National Cancer Institute – December 6, 1995).
This is a very big percentage for such a large study over such a long period. Good news for men who like tomatoes and tomato products. Those who don’t might want to consider some of the other food sources of lycopene or a good lycopene and mixed carotenoid supplement.
Lycopene and Pancreatic Cancer
A Canadian study investigating the effects of dietary carotenoids on pancreatic cancer risk over several years found that lycopene from tomatoes was associated with a 31% reduction in pancreatic cancer for those who consumed the most tomatoes/tomato products versus those who consume the least (Dietary Intake of Lycopene is Associated with Reduced Pancreatic Cancer Risk – The Journal of Nutrition – March 2005).
Lung Cancer and Lycopene
Another study into the effects of carotenoid consumption on the incidence of lung cancer found a significant reduction in lung cancer risk was associated with higher lycopene intake in the diet (Colorful Cancer Prevention: Alpha Carotene, Lycopene and Lung Cancer – American Journal of Clinical Nutrition – October 2000.)
Two passages from the studies notes really stood out to me:
The first – “Diets that provide 400 to 600 grams of fruit and vegetables daily are associated with a reduced risk of lung and other aerodigestive epithelial cancers. Fruit and vegetables contain a variety of carotenoids that have been shown to have antioxidant and antitumor effects. Although smoking is the cause of >90% of all lung cancers, an increased intake of fruit and vegetables has been associated with a decreased risk of lung cancer in smokers and non-smokers.”
And the second: “A significant reduction in cancer risk was noted with an increased intake of lycopene, even in smokers. Interestingly, smoking alters the concentrations of most carotenoids, including alpha carotene and beta carotene but not lycopene. Therefore, lycopene may have a special role in lung cancer prevention.”
It would seem smokers would do well to get into extra tomatoes and tomato products.
Tomatoes, Lycopene and Cancer
And in more of a summary study entitled – Tomatoes, Tomato-based Products, Lycopene and Cancer: Review of the Epidemiologic Literature in the Journal of the National Cancer Institute, studies regarding intake of tomatoes, tomato-based products of blood lycopene levels in relation to the risk of various cancers were reviewed.
To quote: “Among 72 studies identified, 57 reported inverse (positive) associations between tomato intake or blood lycopene levels and the risk of cancer defined at the anatomic site; 35 of the inverse associations were statistically significant. No study indicated that higher tomato consumption or blood lycopene level statistically significantly increase the risk of cancer at any of the investigated sites.”
Some further entries from the study:
On tomatoes, lycopene and stomach cancer – “While other fruits and vegetables have frequently been inversely associated with stomach cancer, inverse associations with tomatoes have been amongst the most consistent and strongest.”
On colorectal cancer and lycopene – “Case controlled studies in Italy and China reported about a 60% reduction in the risk of both colon and rectal cancers associated with higher tomato consumption.”
On lycopene and prostate cancer – “High intake of tomatoes and tomato products, which accounted for 82% of lycopene, reduced risk of total prostate cancer by 35% and aggressive prostate cancer by 53%. Tomato sauce had the strongest inverse association with prostate cancer risk.”
Studies like these can give us an idea of the potential benefits of a health nutrient like lycopene. The official line is that there is not enough evidence yet to recommend lycopene. Meanwhile cancers like prostate, pancreatic and lung cancer kill many thousands of people in the USA every year. We may not have enough empirical evidence yet, but personally, after researching these last few posts, I have a good enough idea on it to increase my lycopene dosage and intake.