*Reprinted from CancerWire, a monthly newsletter distributed by Cancer Monthly (www.cancermonthly.com)
Research is revealing that diet can help prevent cancer and may help treat it too. When will we see the clinical trials?
Today, most people know that lifestyle choices can affect the risk of getting cancer. While many authorities are quick to argue that lifestyle choices are wholly responsible, this is not true. We cannot control the pesticides, herbicides, fungicides and other carcinogens that we are exposed to on a daily basis from the food we eat, the water we drink, and the air we breathe. Yes, smoking can lead to lung cancer, but what about the diesel fumes we breath as we drive behind an 18-wheeler?
The arguments about the causes of cancer are as much political as they are scientific. Once a cancer cause has been accepted by science and law there is an immense and dramatic change in fortunes. Take for example, the asbestos industry. Asbestos was manufactured and used by some of America’s largest corporations which kept quiet the fact that this mineral was carcinogenic and potentially deadly. Once it became known, the eventual litigation bankrupted many of these companies and changed the way this mineral was used forever.
Although our environment is full of carcinogens their existence is often tied to the status quo of industry and production. This means that politics, power, and wealth, not science alone, ultimately determine what is considered cancer causing and what is removed and when.
We do not believe in blaming the victim for their cancer because of their lifestyle choices. This seems to be a popular and convenient approach to the subject. For example, in the recent ABC News story “Eating Healthy Cuts Cancer Risk, Too” the writer explains that being overweight and obese is connected to an increased risk of several different types of cancers, such as breast cancer in post-menopausal women, as well as cancers of the colon, endometrium (uterus), esophagus and kidney.
While there are studies that support such a relationship, blaming cancer solely on obesity, smoking and other lifestyle choices keeps the focus off the elephant in the room – namely the millions of tons of toxins that are poured into our environment as a by-product of industry and mass agricultural practices. So why write about cancer and diet? It is an important subject for at least two reasons:
1) Given how little each of us can control our total environment (i.e. what is in our food, water, and air) we should seek to create a diet that gives us the best opportunity to maintain or regain our health;
2) The connection between diet and cancer prevention is now being expanded into understanding the connection between diet and cancer treatment and this is an important subject for any cancer patient.
Diet and Cancer Risk
The fact that diet can help prevent certain cancers has been known for decades. For example, in a recent case-control study from Taiwan, the researchers stated, “A reduced risk for lung cancer was found to be associated with increased intakes of vitamin A, alpha-carotene, and beta-carotene from 13 food items.” The study concluded that “higher consumption of vitamin A-rich vegetables, especially garland chrysanthemum and sweet potato leaves might provide potential protection from lung cancer.”
As human studies continued to accumulate on the relationship between diet and cancer risk, current research within the human genome is now explaining how it works.
The Biological Mechanisms of Diet and Cancer Risk
How do specific dietary ingredients actually prevent cancer? The pathways and biological mechanisms are being mapped now and it appears that some of these substances may actually work at the genetic level. A recent article from the Department of Medicine at Flinders University in Adelaide, Australia, summarizes the current state of scientific knowledge on this topic:
“Dietary factors might interact in several ways with the genome to protect against cancer. An agent might interact directly with the genome and regulate expression (as a genetic or epigenetic regulator) or indirectly by influencing DNA ‘repair’ responses and so improve genomic stability. Research now shows that diet-genomic interactions in cancer go beyond interactions with the normal genome and involve enhancement of normal cellular responses to DNA damage such that genome stability is more effectively maintained. Activation of apoptosis may be a key to protection.”
And this is likely a two-way street – while certain dietary factors may protect against cancer at the genetic level other dietary factors can contribute to cancer within the gene. For example, in this recent study published in the World Journal Gastroenterology people who ate diets rich in nitrosamines had a greater likelihood of developing esophageal cancer. Obviously, the relationship between ingesting carcinogens and cancer is not new. What is new is that scientists reported that this correlation was due to the effect this unhealthy diet had at the genetic level – specifically on chromosomal mutations in exon 6 of Tp53 gene. This gene is known as a tumor suppressor gene and its lack of proper functioning has been implicated in most cancers.
Diet as a Cancer Treatment
Research on the biological mechanisms between cancer prevention and diet suggest a critical and obvious question – if dietary ingredients such as specific foods, herbs, etc., working at the cellular or genetic level can help prevent cancer, can they also help to manage, control or treat a cancer that already exists? The alternative community has argued for decades that it can based on a combination of clinical research, in vitro studies, and anecdotal information from long-term cancer survivors. Many of these survivors had rejected conventional therapies (chemotherapy, surgery, and radiation) and had instead relied on dietary factors, supplements and other alternative regimens.
Current research continues to support this proposition. For example, one recent study that appeared in the Journal of the American Medical Association (JAMA) demonstrated that a higher intake of a Western dietary pattern after cancer diagnosis was associated with a significantly worse disease-free survival in patients with Stage III colon cancer. According to an article written about this study that appeared in the August 15th edition of Voice of America, “The high fat diet chosen by many people in developed countries — and a growing number of those living in developing countries — is called the Western Pattern Diet. In the study, those cancer patients who ate fattening foods had almost four times the risk of reoccurrence or death. Dr. Jeffrey Meyerhardt (one of the study’s authors) adds, ‘The biggest surprise is actually the impact that a western pattern diet seems to have.’ Patients who switched to greater quantities of fruits, vegetables, poultry and fish appeared to fare better.”
And in a study from Ohio State University, researchers tested the anti-cancer effects of anthocyanin-rich extracts from a variety of fruits and vegetables on colon cancer cells. Anthocyanin pigments are responsible for the red, purple, and blue colors of many fruits, vegetables, cereal grains, and flowers. Researchers retrieved these anthocyanins from fruits and other plants, including grapes, radishes, purple corn, chokeberries, bilberries, purple carrots and elderberries. Science Daily reported, “The plants were chosen due to their extremely deep colors, and therefore high anthocyanin content…The researchers found that the amount of anthocyanin extract needed to reduce cancer cell growth by 50 percent varied among the plants. Extract derived from purple corn was the most potent, in that it took the least amount of this extract (14 micrograms per milliliter of cell growth solution) to cut cell numbers in half. Chokeberry and bilberry extracts were nearly as potent as purple corn. Radish extract proved the least potent, as it took nine times as much (131 µg/ml) of this compound to cut cell growth by 50 percent. ‘All fruits and vegetables that are rich in anthocyanins have compounds that can slow down the growth of colon cancer cells, whether in experiments in laboratory dishes or inside the body,’ said Monica Giusti, the lead author of the study and an assistant professor of food science at Ohio State University.”
Like the relationship between cancer and prevention, the biological mechanisms that explain how dietary elements, herbs and other ingredients can actually slow or arrest cancer is beginning to be understood. And, like prevention, these molecules appear to act on the cells at the genetic level and within our immune systems.
For example, in a recent study from Japan, the ingredients in ginger were found reduce the viability of gastric cancer cells in vitro. Scientists were able to trace exactly how this worked and found that tumor necrosis factor (TNF)-related apoptosis-inducing ligand or “TRAIL” induces apoptosis of tumor cells but not most normal cells. Ginger has been used throughout the world as spice, food and traditional herb. Now, there is evidence that 6-gingerol, a phenolic alkanone isolated from ginger affects a complex biological mechanism that reduces the viability of gastric cancer cells.
And in another recent study, the herb Saw Palmetto was found to induce growth arrest and apoptosis in androgen-dependent prostate cancer cells in vitro by:
· Inducing apoptosis of LNCaP cells in a time- and dose-dependent manner.
· Increasing the expression of p21waf1 and p53 protein in LNCaP cells.
· Down-regulating DHT- or IL-6-induced expression of prostate specific antigen in conjunction with down-regulation of the level of androgen receptor in the nucleus.
· Down-regulating the IL-6-induced level of the phosphorylated form of STAT 3 in LNCaP cells.
This technical terminology can be quite confusing. But, the point is that there is hard science accumulating that certain dietary ingredients and medicinal herbs have efficacy in reducing cancer through genetic, cellular and immune pathways.
Where are all the clinical trials for food and herbs?
Clinical trials are expensive to run and there is an expectation that a profit can be made from a new drug or therapy. However, because ginger, saw palmetto, low-fat diets, anthocyanins and other naturally occurring molecules are difficult to patent, drug companies are hesitant to invest in them. Nonetheless, research into human biology is beginning to illustrate that the statement by Hippocrates, the ancient Greek physician and the Father of Medicine, “Let your food be your medicine, and your medicine be your food” was likely correct. Unfortunately, until economic incentives are altered it is unlikely that cancer patients will be given the option of a clinical trial based wholely or partly on diets, herbs, and other naturally occuring substances. Patients interested in dietary approaches will have to continue to perform their own research by reading and speaking to professional health practitioners experienced in this area.