The complicated relationship between immune system functioning and cancer is often misunderstood, according to Tim Birdsall, ND, the vice president of integrative medicine at Cancer Treatment Centers of America and a member of the National Advisory Council for Complementary and Alternative Medicine for the National Institutes of Health.
Your immune system is designed to recognize and destroy abnormal cells. But in many instances, especially in early stage cancers, the surface markers on cancerous cells are identical to those on normal cells, making it impossible for your immune system to recognize them as a threat.
Although boosting your immune system isn’t an actual treatment for cancer, it’s incredibly important as you fight cancer. Cancer patients are susceptible to infection from the disease, as well as from treatments that destroy white blood cells.
“Infection is a huge issue to cancer patients,” Birdsall says. “It is important to do things to boost the immune system and reduce the likelihood of infection.”
Here are supplements, vitamins, and extracts you may hear about to help boost the immune system.
Vitamin D is one of the most studied supplements for cancer prevention and treatment right now.
“ Vitamin D is of interest not so much because of results of clinical trials, but because of our evolving understanding of the key role it plays in cell [development] and the fact that so many people are really deficient in vitamin D,” says Tim Byers, MD, deputy director of the University of Colorado Cancer Center.
Epidemiological studies have found that people with cancer often have lower circulating levels of vitamin D in their blood. However, the research is mixed.
In a study presented at the 2008 meeting of the American Society of Clinical Oncology, researchers found that vitamin D deficiency was more common among women diagnosed with breast cancer. The study also found that vitamin D deficiency may raise the risk of breast cancer spreading, and raise the risk of death from breast cancer.
But in a large National Cancer Institute study, researchers found no association between blood levels of vitamin D and cancer death, with the possible exception of colorectal cancer. People with high levels of vitamin D were 72% less likely than those with low levels to die of colorectal cancer.
Also, some studies have found that vitamin D may protect against prostate cancer, while other studies have found that it doesn’t help.
There continues to be a flurry of research looking at vitamin D’s role in cancer. More research is needed to truly understand the relationship.
Many studies have found that people who eat a lot of garlic are less likely to develop certain common cancers.
That garlic research has led scientists to wonder whether garlic may have cancer-treating properties as well as cancer-prevention capabilities. Although studies are not yet conclusive, there is some evidence that garlic may be useful for cancer in conjunction with medical treatments.
For starters, garlic may be beneficial for cancer patients owing to its immune-boosting abilities, which vary depending on how the garlic has been processed. Additionally, certain substances found in garlic have been shown to suppress growth and fight certain cancerous cells in the lab, including forms of breast and lung cancer.
Early studies have shown that eating garlic can decrease the risk of colorectal cancer and stomach cancer. The same benefit was not found with garlic supplements. However, preliminary prostate cancer research on men in China has shown that both eating garlic and garlic supplements may decrease the risk of prostate cancer.
Green tea contains substances called polyphenols that are believed to have powerful anti-cancer abilities.
Cancerous tumors rely on fast-growing networks of blood vessels to sustain their rapid growth rate. Green tea compounds may possess the ability to help slow or prevent this rapid growth. “Green tea seems to inhibit the development of new blood vessels in tumors, and provides one more approach that can be used to strangle tumors,” Birdsall tells WebMD.
Because it would take the equivalent of drinking 10 to 12 cups of green tea each day to obtain the cancer-fighting levels of green tea compounds, Birdsall recommends that his patients take green tea in extract form. Be aware, there are some concerns about green tea extracts and liver toxicity. Also, a recommendation of 10 to 12 cups of green tea per day would be for cancer treatment, not cancer prevention.
Drinking green tea may increase the survival rates of some cancer patients. One study of women with ovarian cancer found that women who drank green tea were more likely to survive three years after ovarian cancer diagnosis than women who did not drink green tea. The survival rates increased with higher consumption levels of green tea.
Drinking green tea may also help prevent certain cancers. Preliminary research suggests a possible protective effect against bladder, esophageal, pancreatic, ovarian, and possibly cervical cancer, even with as little as 3-5 cups a day. Evidence for breast, stomach, and lung cancer is mixed: studies have conflicting findings.
Extracts from mushrooms have been used in traditional Asian medicine for thousands of years. More recent scientific studies are beginning to determine reasons for their potential health-promoting actions.
For example, polysaccharides (phytochemicals) from the Ganoderma lucidum mushroom have been shown to inhibit the growth and invasiveness of some cancer cells in the laboratory, including certain forms of breast cancer.
Other fungal varieties that may exhibit anti-cancer activity include reishi, shiitake, maitake and coriolus or turkey tail, mushrooms.
Lentinan, a substance found in shiitake mushrooms, has been shown in the lab to inhibit the growth of human colon cancer cells in mice. This may result from lentinan’s ability to inhibit some enzymes that promote the activity of cancer-causing substances called carcinogens. Beta-glucan, a compound found in maitake mushrooms, is also thought to have tumor-fighting properties, though data on these abilities is still quite limited.
Keep in mind that the studies so far have looked at how these mushroom extracts affect cancer cells in the lab, with only a few documenting the effects in the human body. More research is needed.
Antioxidants are substances found in abundance in fruits and vegetables – and in lesser amounts in nuts, grains, and meat. These phytochemicals fight certain oxygen molecules in your body known as free radicals, which can damage DNA and contribute to the development and proliferation of cancerous cells.
The use of antioxidants for cancer prevention and treatment is a controversial and confusing topic. Although experts once believed that megadoses of certain antioxidants, including vitamins A and E, might be beneficial, clinical studies have raised questions about the safety of this practice. Studies have shown that high doses of certain antioxidants can increase cancer occurrence in some populations. For instance, smokers who take high doses of beta carotene are at increased risk for lung cancer.
Some experts worry that the use of antioxidants during radiation therapy and chemotherapy might serve to protect the very cancer cells that are being targeted. A 2008 study in Cancer Research showed that vitamin C supplements blunted the effectiveness of chemotherapy by 30% to 70%.
Although more research needs to be done, there is data to suggest that antioxidant supplements may improve quality of life for some cancer patients. For example, the combined use of antioxidants in green tea, melatonin, and multivitamins containing high doses of vitamins C and E was shown to reduce pain and fatigue in patients being treated for pancreatic cancer.
In the meantime, there’s no doubt that a diet high in antioxidant-rich foods, such as fruits and vegetables, has numerous health benefits.
Be sure to talk with your cancer treatment team before taking antioxidant supplements when you have cancer.