Tea, especially green tea, contains a compound that inhibits cancer cell formation and provokes cancer cell death, among other actions.
Q. Reading all of the reports on cancer prevention is really confusing me. Which anticancer herbs should I include in a daily regimen to stay healthy and reduce my risk of cancer?
A. First off, I’m glad to hear that you want to act now to reduce your cancer risk. Cancer takes years to develop. Prevention, if possible, is preferable to treatment. Avoid known carcinogens such as tobacco smoke, and have the routine screening tests that catch cancer in early, more-treatable stages.
As always, a healthy lifestyle is key. Eat a plant-based diet, exercise regularly and get enough sleep. Those strategies will also help keep your weight under control. Obesity raises the risk of diabetes, and both conditions are associated with an increased risk of cancer.
A plant-based diet can help shield you from cancer because plants are rich in anti-inflammatory and antioxidant substances that help them (and us) withstand exposure to ultraviolet radiation, air pollution and other noxious substances. (Oxidative damage and inflammation promote cancer as well as a number of other chronic diseases.) Furthermore, some plant chemicals enhance the body’s detoxification systems, stimulate the immune system and have direct anticancer effects.
Weeds are the true survivors. They burst through sidewalk cracks and weather pollution, drought, neglect and outright abuse. Researchers have only begun to investigate the anticancer effects of plants like dandelion (Taraxacum officinale) and stinging nettle (Urtica dioica). Nevertheless, I recommend including those two nutrition powerhouses in your diet. If you have access to fresh, pesticide-free leaves, you can steam or sauté them. (Use gloves when picking nettles, as they sting until cooked.) You can also drink infusions of the dried or fresh leaves.
Other foods to include are cruciferous vegetables, asparagus, and Alliums, such as garlic and onions, which all contain sulfurous anticancer compounds. Lycopene, a carotenoid chemical found in high concentrations in tomatoes, pink grapefruit, watermelon and guava, has anticancer action. Cooked tomato products are best, as the processing increases the body’s ability to absorb lycopene. The same is true of the isoflavone genistein, found in soybeans.
Another simple strategy is to increase your consumption of polyphenol-rich foods. Polyphenols, such as flavonoids, contribute to the plant’s color. For instance, fruits with deep red, purple and blue colors—red grapes, cranberries, blueberries, pomegranates—all have anticancer effects. But some powerful cancer-fighting, polyphenol-rich plants and anticancer herbs, such as green tea, turmeric and milk thistle, do fall outside the blue-purple color scheme.
Black, green and oolong tea all come from the same plant—Camellia sinensis. Population studies link higher tea consumption with a reduced risk of gastrointestinal, pancreatic, bladder, prostate, ovarian, uterine and breast cancer. Green tea is particularly rich in a polyphenol called epigallocatechin gallate. In lab research, it inhibits cancer cell formation, proliferation, invasiveness, and metastasis and provokes cancer cell death. Aim for three to five cups of green tea a day.
Turmeric (Curcuma longa) and its botanical cousin ginger (Zingiber officinale) are anticancer herbs that contain the potent anti-inflammatory, antioxidant, and anticancer polyphenols curcumin and gingerol, respectively. Most of the cancer research has focused on curcumin, which has multiple anticancer effects. It protects against DNA mutations; stimulates enzymes that repair damaged DNA and those that detoxify carcinogens; inhibits tumor formation, growth and migration; discourages angiogenesis (the creation of blood vessels that feed the cancer); and induces cancer cells to die.
However, curcumin is soluble in fat but not water, isn’t well-absorbed from the intestinal tract into the bloodstream, and breaks down quickly. Some supplement manufacturers improve bioavailability by combining it with bromelain (an enzyme in pineapple), piperine from pepper, or phosphatidylcholine. Cancer researchers have been working to create stable formulations that could be given intravenously to people undergoing cancer treatment.
The optimal dose for curcumin is not clear. In the meantime, eat curried vegetables. Turmeric is the main ingredient in curry spice. The pepper in the curry blend and the oil used in cooking will aid curcumin absorption.
While better known as an herb that protects the liver, milk thistle (Silybum marianum) also has cancer-protective effects. It contains an antioxidant, anti-inflammatory flavonoid complex called silymarin. Research shows that it promotes repair of DNA, blocks angiogenesis, and suppresses proliferation and metastasis of a variety of cancers.
You can take milk thistle as a tincture or standardized extract. You can also make the ground seeds into tea or sprinkle them atop foods. Milk thistle’s delicious relative, the artichoke (Cynara scolymus), also contains polyphenols.
Consumption of garlic (Allium sativum) and onion (Allium cepa) is associated with a reduced risk of some cancers. Lab studies further support this anticancer action of these anticancer herbs. Garlic increases enzymes that detoxify carcinogens, inhibits proliferation of cancer cells, induces cancer cell death and boosts immunity. Crush the bulb and allow it to sit for 10 minutes before consuming, which will increase an active ingredient called allicin. Because heat deactivates allicin, use raw, minced garlic in dressings, dips, soups and sauces, or add it to hot food just before serving.
Edible mushrooms contain highly branched polysaccharides called beta-glucans and other ingredients that both enhance immunity and have anticancer properties. Eating mushrooms correlates with a lower risk of breast cancer. Even the pedestrian button mushroom available at most supermarkets can enhance immune cell functions involved with cancer containment. Three of the better-researched medicinal mushrooms are shiitake, maitake and reishi.
Shiitake (Lentinula edodes) has immune-enhancing and anticancer effects. Asian research shows that an extract called lentinan enhances survival time in people with cancer. Due to poor oral absorption, lentinan is given by intravenous or intramuscular injections. Other components of shiitake, such as LEM (Lentinula edodes mycelia) extract, are active when taken by mouth. The fresh mushroom is delicious sautéed (with or without garlic). The dried mushroom can be taken in tea or soup. Concentrated extracts are also available.
Research on purified maitake (Grifola frondosa) extracts called “D-fraction” and “MD-fraction” demonstrate several anticancer actions: protection of healthy cells from becoming cancerous; inhibition of the growth and spread of tumors; induction of cancer cell death; enhancement of the effectiveness of anticancer drugs; and mitigation of some of their side effects. Maitake also increases natural killer cells, immune cells that attack tumor cells.
Maitake extracts produce benefits when taken by mouth. However, research in humans is scant and exact dosages aren’t yet defined. You can also consume this anticancer herb in tea or as a food (in soups, stir-fry, etc.). Higher-end grocery stores carry fresh maitake, also called “hen of the woods.”
In Traditional Chinese Medicine, reishi (Ganoderma lucidum) has the reputation of promoting health and longevity in people with and without cancer. Lab research shows that reishi extracts inhibit the proliferation and spread of breast, prostate, lung and liver cancer cells; stimulate cancer cells to die; and block the formation of new blood vessels to tumors. Reishi and green tea have a synergistic effect in thwarting the ability of breast cancer cells to invade and migrate.
Human trials have recently begun. Two studies showed that reishi enhances immune function in some people with advanced cancer. You can take reishi in teas, tinctures, syrups, tablets or standardized extracts.
Linda B. White, M.D., is a visiting assistant professor in the Integrative Therapies Program at Metropolitan State College of Denver.