Vegetables and Their Anti-Cancer Effects

"Cancer is caused by a combination of many different behavioural, physical, environmental and genetic risk factors which include smoking, UV exposure, age, poor diet and lack of physical activity, as well as exposure to certain chemicals, viruses or bacteria. It is believed that the diet contributes to one third of all cancer deaths.

Various epidemiological data has demonstrated that high fruit and vegetable consumption, over 5 servings per day, decreases the overall risk of many different cancers by approximately one half. The beneficial effects of fruit and vegetable consumption have been linked to their anti-oxidant and anti-proliferative effects. Anti-proliferation targets the later progression stages of cancer and helps prevent the spread of the disease.

A recent study set out to find the anti-proliferative and anti-oxidant effects of 34 different vegetables such as carrots, tomatoes and green beans in eight different types of cancer cells kept alive outside the body. These included stomach, kidney, prostate, breast, brain, pancreatic and lung cancer cells.

Results revealed that prostate and stomach cancer cell lines were most sensitive to the extract treatments. The prostate cancer cells were reduced by 50% or more in 23 of the 34 vegetable extracts tested and stomach cancer cells were reduced by 50% or more in 19 of the 34 vegetable extracts tested.

In lung, pancreas and kidney cancer lines, this decrease only occurred in 14, 12 and 7 of the 34 vegetable extracts. This may indicate that prostate and stomach cancers are more sensitive to dietary influences. The vegetable extracts that demonstrated >50% inhibition in all cell lines were Brussel sprouts, cabbage, curly cabbage, garlic, green onion, kale, leek and spinach. Garlic extract diluted at 1/1000 demonstrated complete inhibition of the [brain] cell line. At this dose, it was the most potent inhibitor of proliferation.

In addition, the anti-oxidative capacity of each vegetable extract was quantified. Garlic, curly cabbage and Brussel sprouts had the highest oxygen radical absorbance capacity (ORAC)* values of 41.1, 40.5, and 32.9 µmol Trolox** equiv./ml respectively. Acorn squash and English cucumber, had the lowest values of 1.5 and 1.4 µmol Trolox equiv./ml.

In conclusion, this study demonstrates that the anti-carcinogenic properties of these vegetables produce anti-oxidative and anti-proliferative effects that help decrease cancer risk."

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