Recently a family member sent me one of those mass forwarded emails “Lemons and Cancer,” claiming that … “lemon (citrus) is a miraculous product to kill cancer cells. It is 10,000 times strong than chemotherapy. Why don’t we know about that? Because there are laboratories interested in making a synthetic version that will bring them huge profits.”
Is this really true? I couldn't let this one go without a reply and sent her information that I'd learned in a course about bioactive compounds (also called phytochemicals).
Bioactive compounds are substances in foods that have a health benefit but they are not classified as a vitamin or mineral. There are several categories of bioactive compounds, and lemons (and limes, oranges, and grapefruit) contain those in the terpene category, specifically “limonene.” There are others, but this one has been most often studied for its cancer protective benefits.
Most of the studies to determine health benefits have been in animals, not humans. The animal studies have consistently shown that limonene can protect against skin, breast, lung, stomach, color and kidney cancers. Limonene has been shown to interfere with the formation and growth of tumors.
Most people consume about 50 mg/day of limonene from food (based on a study in Arizona). The studies typically used a much higher amount (500 mg or more) – much more than people actually eat. While there a health benefit associated with eating fresh lemon, lime, orange or grapefruit every day, it would not be likely that you could eat enough citrus fruit for it to be medically relevant (i.e. for cancer treatment). Lemons are rich in vitamin C and other bioactive compounds including carotenoids and flavonoids.
It is best to eat fresh citrus vs. juice in cartons. Studies have shown that the limonene content was lower in juices packaged in plastic or cartons. The peels are especially rich in limonene so use the zest too! Use lemon zest and fresh juice on vegetables, fish, avocado, or rice. Squeeze fresh lemon juice in your water for a refreshing summer drink.
My advice: eat a variety of fruits and vegetables, including lemons, every day – the studies have shown that people who eat a higher number of daily servings have a lower risk of cancer and many other chronic diseases. The nutrients in whole foods have a synergistic effect, so they are always a better choice than isolated nutrients.