Nearly $100 billion has been spent on research since the government declared its war on cancer and only a fraction of those funds have been devoted to studying prevention of the disease. Yet, the consensus among experts is that one-third to one-half of all cancers can be avoided through diet and lifestyle modification.
Advances in gene editing and immunotherapy offer hope that we may someday have a cure for cancer but many current treatments cause debilitating side effects, are incredibly expensive and often only increase life expectancy by a few weeks. Prevention is the one avenue that we know for certain will save lives. Since cancer development and progression is multifactorial, the most effective prevention action plan will be multipronged, minimizing exposure to as many environmental triggers as possible. Diet is the one factor you have complete control over.
Discussions of diet and cancer prevention usually focus on foods like broccoli, green tea and berries and with good reason, as all contain high concentrations of antioxidants. These compounds fight the internal “rusting” process known as oxidation, which increases disease risk. However, cancer is complex and takes hold via several mechanisms, including one known as angiogenesis. This refers to the growth of new blood vessels. Without angiogenesis, cancer can’t grow.
According to the Angiogenesis Foundation, “cancerous tumors release angiogenic growth factor proteins that stimulate blood vessels to grow into the tumor, providing it with oxygen and nutrients.” Dr. William Li heads the organization and has identified a list of anti-angiogenic foods, some of which may surprise you. Here are some of these lesser-known anti-cancer foods:
Artichokes contain unusually high levels of antioxidants known as phytochemicals. According to a study published in the American Journal of Clinical Nutrition, artichokes rank number one in antioxidant content of all the foods tested.
Research shows that the antioxidants rutin, quercetin and gallic acid found in artichoke leaf extract reduce the proliferation of cancer cells and induce apoptosis, a type of cell suicide. In research done at Comenius University in Slovakia, artichoke leaf extract was studied for its ability to inhibit the growth of leukemia cells. Over a 24-hour period, leukemia cells were treated with various concentrations of artichoke leaf extract. Results suggested that it exerts an antiproliferative activity on leukemia cells while inducing apoptosis of these cells as well.
Researchers at the University of Georg-August in Germany have concluded that the many phytochemicals in artichokes help to block the secretion of cancer agents, thereby preventing angiogenesis. Artichokes contain a flavonoid known as silymarin, which has been shown to lower the risk of skin cancer. In one study, cancer cell movements and invasions were inhibited. Additional research has shown that compounds in artichokes protect cells from oxidative stress and reduce cancer cell viability and activity on a human liver cancer cell line.
TIP: Consume a 1/4 cup of artichokes several times per week to reap the benefits. Steam them yourself or look for marinated varieties at the supermarket. Throw them over salad or roast them with garlic and lemon. Here’s a recipe for a more nutritious version of the popular spinach and artichoke dip.
Parsley is abundant in a substance known as apigenin, which has demonstrated powerful growth-inhibitory effects on breast cancer cells. Studies suggest that apigenin also induces apoptosis in human skin, thyroid, gastric, liver, colon, cervical, and prostate cancer cells, and that it may inhibit migration and invasion of ovarian cancer cells.
In research published in September 2015 in the journal Oncotarget, scientists were able to show for the first time that apigenin is able to effectively slow down or stop an undesirable enzyme called IKKA, which plays a role in cancer progression. A 2013 study out of China found that apigenin killed up to 86 percent of lung cancer cells in vitro.
Parsley also contains 8-methoxypsoralen, a compound that has been shown to prevent the development of carcinogen-induced lung cancer. In addition, parsley is a source of both imperatorin and isopimpinellin – two phytochemicals known to have chemopreventive effects in liver, lung and mammary epithelial cells. The oil from both parsley leaf and seed contains myristicin. Research has demonstrated that myristicin hinders the proliferation of lung cancer in mice.
- Luteolin has been shown to induce death in oral and colon cancer cells, to promote cell cycle arrest and to halt insulin-like growth factor 1 (IGF-1) receptor signaling in prostate cancer cells. (IGF-1 is a powerful “switch” that turns on cancer cell proliferation.) Luteolin has also been shown increase the anti-cancer effects of chemotherapy drugs such as Taxol (paclitaxel) and to inhibit the proliferation of breast cancer cells.
- Quercetin may slow proliferation of estrogen receptor negative (ER-) breast cancer cells. A major Italian population study including 2,569 women with breast cancer found that the risk of breast cancer was reduced with increased consumption of such flavones.
- Lutein intake and circulating lutein levels have been associated with reduced risk of breast cancer in several epidemiological studies.
TIP: The antioxidant capacity of parsley is enhanced when it is used in soups or stews (i.e., when it is boiled) but is reduced when grilled or fried.
Bromelain, an enzyme found in pineapple, has exhibited antitumorigenic properties and is used in clinical settings to complement chemotherapy. According to the authors of one study: “Bromelain afforded substantial anti-cancer potential” in carcinoma and melanoma cell lines. Researchers noted “an increase in apoptosis-related cell death in breast cancer cells with increasing concentrations of bromelain.” Again, apoptosis is when the cell literally eats itself alive!
A study published in 2007 in Plant Medica concluded that the anti-tumor abilities of bromelain are superior to the effects of the chemotherapy drug 5-fluorouracil (5-FU). Unlike 5-FU, bromelain doesn’t kill healthy cells. Bromelain is often used in naturopathic oncology after initial treatment to prevent the formation of secondary tumors.
Bioactive polysaccharides are important components of pineapple that might also contribute to its health benefits. They exhibit “significant antitumor cell proliferation activities against breast carcinoma cell line and strong antioxidant activities.” It also “appears to impair cancer cell survival” in gastric cancer according to a 2013 article in OncoTargets and Therapy.
TIP: Choose the whole fresh fruit and cut it up yourself, as most of the bromelain in canned pineapple has been destroyed. Try adding pineapple to a smoothie with kale, whey protein and coconut milk.
Although pineapples are packed with other vitamins and minerals, if have a family history cancer or would like a more potent cancer-fighting “punch”, you should consider a bromelain supplement. A dose of between 80 and 320mg a day is considered safe and effective. As an added bonus, bromelain helps with digestion, speeds healing and is a natural anti-inflammatory.
Research has identified a compound found in licorice root that slows the growth of cancer cells during laboratory tests. Licochalcone-A has been shown to have antitumor activity in acute leukemia, breast, and prostate cancer cell lines by lowering the amount of bcl-2, a drug-resistant protein. Excess amounts of this protein are frequently associated with these cancers. The findings were presented at the International Conference on Molecular Cancer Therapeutics sponsored by the American Association of Cancer Research (AACR), National Cancer Institute (NCI), and European Organization for Research and Treatment of Cancer (EORTC). Additional research on Licochalcone-A has demonstrated anti-inflammatory effects. Recall that inflammation is considered to be the underlying cause of all chronic, degenerative disease.
When scientists extracted another compound from liquorice root -Isoangustone A – and applied it to skin cancer cells it slowed the rate at which melanoma cells reproduce, in part by blocking the release of specific proteins needed for them to flourish. Similar effects were seen with prostate cancer cells
TIP: We’re not talking about the artificial licorice candy. Look for licorice root extracts that do not contain glycyrrhizin, which can cause high blood pressure. These extracts will say deglycyrrhizinated licorice (DGL) on the label and do not have the undesirable side effects of other forms of licorice supplements. As for whole licorice, a typical dose is 5 to 15 g daily for a few weeks at a time. For long-term consumption, Lahey Hospital and Medical Center recommends about 0.3 g of licorice root daily as a safe dose for most adults. You can also cook with the stuff. Check out this chicken recipe.
The essential oils in nutmeg contain compounds like geraniol, saffrol, limonene. Together, these provide antioxidant, anti-inflammatory and other protective activities. The oils inhibit oxidation of the essential fatty acid, linoleic acid and significantly reduce the new blood vessel growth that feeds tumors, according to a study in the April 2012 issue of the Asian Pacific Journal of Tropical Medicine.
In a 2007 study, nutmeg extract killed human leukemia cells. Myristicin, a component of nutmeg essential oil, inhibits the growth of colon cancer cells.
TIP: The flavor of nutmeg peaks the moment you grate it, so it’s best to add it toward the end of the cooking process or just before serving. Nutmeg gives a sweet spiciness to savory dishes, such as curries. It’s also great sprinkled over cooked vegetables like cauliflower, onion, eggplant, cabbage, Brussels sprouts and spinach. You can also sprinkle it lightly over veal, fish, or chicken. A little goes a long way so try 1/8 teaspoon per 4 servings to start.
Chronic inflammation is also associated with immunosuppression, which is a risk factor for cancer. Ginseng contains an anti-inflammatory molecule that targets many of the key players in the inflammation-to-cancer sequence. A 2007 article in the Journal of Nutrition determined that ginseng’s secret cancer-fighting weapons are compounds called “ginsenosides.”
Studies exhibit apoptosis in cancer with the use of ginsenosides. Cell death has been demonstrated for several types including breast, ovarian, cervical, lung and prostate cancers, as well as melanoma.
Of particular interest is ginsenosides’ metabolite Rg3. A May 2015 report published in the Chemico-Biological Interactions journal revealed that the average volume of tumors treated was decreased by 40 percent when managed with Rg3.
Cancer cells can break away from a primary site and spread to other parts of the body via the bloodstream or lymphatic system. The invasive transmission poses a threat to life as cancer grows at secondary sites within the body. Recent studies have suggested that ginsenosides inhibit cancer metastasis and decrease its invasive ability.
An experimental study published in a Chinese Medical Journal reported ginsenosides can significantly inhibit the metastasis of ovarian cancer, while another recent study in Tumor Biology reported that it prevents cell proliferation and invasion on prostate cancer. Whether used in isolation or combined with other botanical compounds, an increasing number of studies have demonstrated a significant effect of ginsenosides on halting tumor growth and invasive transmission in some of the most aggressive types of cancer.
TIP: According to studies, Panax ginseng is the most beneficial type in preventing and treating cancer. It’s available in capsule form as a dietary supplement. Since ginseng also has stimulatory properties, the recommendation is for healthy adults to take it daily in the morning or early afternoon. You can also drink a cup of ginseng tea or take 10 to 30 drops of the extract in a beverage.
Fresh or dried ginseng root may also be taken daily at one-half to two grams.
Beta-carotene, the pigment responsible for pumpkin’s bright red-orange color, is a powerful immunostimulant. Studies have found that beta-carotene may give your body a cancer-fighting boost by slowing cancer growth, preventing DNA damage and even enhancing the enzymes that clear cancer-causing substances from the body. Beta carotene accounts for more than 80 percent of the antioxidants in a serving of pumpkin.
Then there’s alpha-carotene, which has direct anticarcinogenic activity. Some studies suggest it’s a more potent cancer inhibitor than beta-carotene. Lutein and lycopene, antioxidant carotenoids found in orange and yellow fruit, are also known to protect other bodily systems. Pumpkin polysaccharides (chains of carbohydrate molecules) have been shown to provide a significant protective effect on healthy cells by increasing antioxidative activity.
Most of the population-based breast cancer studies performed to date that specifically included pumpkins were conducted in Japan, since its consumption is higher there than in the U.S. The Japanese are among the healthiest and longest-living populations in the world so it’s probably a good idea to take a page or two out of their book. In fact, I model much of my health-eating and nutrition supplement strategy on things the Japanese do.
Dietary intake of pumpkin was found to be protective against head and neck cancer in one Eastern European study. Previous research has found that those with very low plasma levels of alpha-carotene and beta-carotene are at a higher risk of gastric cancer and intake of orange and yellow vegetables like pumpkin may also be protective against prostate cancer and non-Hodgkin lymphoma.
Pumpkin seeds are also good sources of micronutrients such as alpha-carotene, beta-carotene, squalene and various cucurbitacins, which were shown in a 2012 study to block breast cancer metastasis by suppressing tumor cell migration and invasion. More recent research has demonstrated a similar effect on lung cancer cells.
Pumpkin seeds contain plant compounds called lignans (also found in flaxseeds) and one lignan in particular – enterolactone – has demonstrated disease-fighting properties, particularly in the area of breast cancer. A 2012 study found a significant association between pumpkin seed consumption and breast health. Another study suggested a role for pumpkin seed lignans in breast cancer prevention. Additional research has shown that a supplement containing pumpkin seeds reported positive potential for dealing with prostate cancer.
A five tablespoon serving of pumpkin provides 20 mgs of vitamin E, which also inhibits cancer cell growth and protects immune cells from free radicals. Vitamin E boosts your immune system and low levels have been shown to increase the risk of several types of cancer. Vitamin E – from food sources, not supplements – may lower the risk of endometrial cancer and reduce bladder cancer recurrence.
TIP: Canned pumpkin (NOT the same as pumpkin pie filling!) has many of the same benefits of fresh pumpkin. Farmer’s Market brand is the one I use. Mix a couple of tablespoons in a smoothie, incorporate it into a curry like this one, or whip up a batch of these delicious, grain-free, sugar-free muffins.
More commonly associated with heart health, olive oil has also been shown to have powerful anti-cancer benefits and scientists have identified several constituents that may be responsible. These include its antioxidant polyphenols, as well as the lipid oleic acid, which is highly resistant to peroxidation – a degradation of the fats it contains that can trigger disease processes.
A team of researchers from Rutgers University and Hunter College recently published the results of a study in the journal Molecular & Cellular Oncology. Oleocanthal, the primary phenolic compound found in extra-virgin olive oil, was shown to eradicate cancer cells in less than an hour! The scientists determined that oleocanthal destroyed the waste centers of the cancer cells, also known as lysosomes. Once oleocanthal did its initial damage, vital functions began to suffer and the cells died soon after. As important, healthy cells stayed intact. “We think oleocanthal could explain reduced [cancer] incidence in Mediterranean diets where consumption is high,” said one of the study authors.
Recently, oncology researchers were excited to discover that oleic acid, the main monounsaturated fatty acid in olive oil, may fight cancer by interacting with the human genome. Oleic acid actually works to suppress the over-expression of a well-characterized oncogene that plays a key role in the invasive progression and metastasis of several human cancers.
TIP: Widespread corruption was recently revealed to plague the Italian olive oil industry resulting in popular brands being “cut” with cheaper oils. For that reason, I recommend products from other regions. I use California Olive Ranch.
Extra virgin varieties provide maximum health benefits compared to more refined forms of the oil but they also have a low smoke point so reserve EVOO for use in salad dressings in order to preserve the nutrients. Aim for 1-2 tablespoons per day tossed with greens or drizzled over cooked veggies.
Pharmaceutical companies know the healing power of plant compounds but they aren’t interested in medicines that can’t be patented and turned into multi-billion dollar blockbuster drugs. However, there’s a growing body of evidence to suggest that we can literally “starve” cancer cells and potentially stop tumor growth. Since the nutrients in these eight foods target several disease processes their benefits go beyond cancer prevention. The foods listed above are accessible and represent a practical way to add flavor to dishes you’re probably already eating.