Cancer, Diet, and the Master Switch

A recently published review* highlights a large body of evidence that active ingredients in fruits and vegetables can not only stave off certain cancers, but also can inhibit the cell division that leads to tumor growth and metastasis.

Although the review specifically examines a number of ways that some fruits and vegetables target cancer at the molecular level, co-author Bharat B. Aggarwal, PhD, of MD Anderson Cancer Center, stresses that diet represents only one front in the battle against the disease. 

The culprit is inflammation, the cause is (usually) lifestyle

Simply put, most diseases, including cancer, are caused by dysregulated inflammation, Aggarwal says. “If we can correct this, we can prevent and even treat cancer.”

But what’s behind this dysregulated inflammation? It’s rarely faulty genes.

“Only two percent of all cancers are caused by genetics,” he says. “Instead, our bodies contain a kind of ‘master switch’ that controls inflammation – and the scientific community has identified more than 400 genes that are regulated by this switch.”

(The formal name of this “master switch” is nuclear transcription factor NF-kappa B, Aggarwal explains, and “it controls a wide variety of physiological and pathological situations in the body through the regulation of various genes. NF-kB resides in the cytoplasm compartment of the cell under normal conditions, but when activated, it translocates to the cell’s nucleus.”)

Under normal conditions, the switch is off, he says. “It’s only when we do certain things that it gets turned on.”

One-third of all cancers are caused by tobacco use, he states, with another third brought on by diet, and the remaining third resulting from various other environmental factors.

“Cancer is a disease of the lifestyle, and it typically takes 20 to 30 years of insult to the body before you get cancer,” he says. “The key is to do the things your grandmother told you to do: eat foods that are good for you, exercise, breathe fresh air, relax, get enough sleep. All these things control the master switch.”

A push for understanding – and a more veggie-friendly world

But back to fruits and vegetables.

The National Cancer Institute advises us to eat eight servings every day. Heeding that advice, however, isn’t always easy, Aggarwal says, recalling observing a colleague pull a bag of carrots from her purse during a medical conference luncheon.

Fruits and vegetables must be more readily available, he says – and in more pleasant, palatable forms; merely boiled vegetables will not do – if people are going to follow dietary recommendations.

“Adding spices makes food more attractive and palatable – and it turns out that many spices themselves prevent cancer by turning off the master switch,” says Aggarwal. “These include ingredients present in tumeric, red chili, cloves, fennel, basil, black pepper, and fenugreek.”

“We also need to do a better job of explaining to people why fruits and vegetables are good for us,” Aggarwal adds. “People need to understand that most currently employed cancer targets are regulated by the master switch – and that the switch can be turned off by eating the recommended amounts of fruits and vegetables.”

The review looked at 206 epidemiological and 22 animal studies of the impact of fruits and vegetables on cancer cell-signaling pathways. Here are just a few of the active ingredients that appear to make a significant difference:

Allicin (Garlic)
Capsaicin (Red chilis)
Catechins (Green tea)
Curcumin (Found in turmeric)
Eugenol (Cloves)
Genistein (Soybeans)
Limonene (Citrus fruits)
Lycopene (Tomatoes)
Resveratrol (Red grapes, peanuts, and berries)

If you have any questions or concerns, or are thinking about adding any new foods to your diet, speak with your doctor.
Aggarwal knows that increasing awareness and understanding will be an uphill battle.

“Billions of dollars are spent advertising drugs to treat cancer,” he says. “Who’s going to spend that kind of money advertising fruits and vegetables?”

* Aggarwal BB, Shishodia S, Molecular Targets of Dietary Agents for Prevention and Therapy of Cancer. Biochem Pharmacol, 2006 May 14;71(10):1397-421. Epub 2006 Feb 23.

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