A MICROSCOPIC VIEW OF THIS CHAPTER
• A healthy diet and your immune system prevent cancer.
• Probiotics eliminate substances known to cause cancer.
• Probiotics stop enzymes involved in the creation of cancer-causing chemicals.
• Prebiotics and probiotics have synergistic effects against colon cancer.
• Liver, bladder and lung cancer could be aided by probiotics.
• Radiation therapy side effects may be alleviated by probiotics.
Your body is made up of hundreds of different types of cells, all of which behave differently. A cell in the liver, although it contains the same genetic information as a brain cell, performs a completely separate role. Every cell has a map of instructions called DNA. Each cell is told when to reproduce, die and repair. When the instructions relating to cell multiplication and dying are wrong, the cell may start dividing uncontrollably and not die when it should. The problem then is every time the cell divides, these bad instructions are reproduced. The result is out-of-control multiplication. A lump or tumor develops as these cells grow faster than the healthy cells around them. As it continues to grow, the tumor builds its own blood vessels and becomes an uncontrolled entity in the body.
Why does cancer harm health and at times result in death? A tumor can grow to sizes that obstruct the ability of nearby organs to function. For example, a pancreatic tumor could grow to a size that reduces the ability of the bile duct to function. The result is improper digestion and poor liver function. Tumors can also produce hormones and enzymes that interfere with regular body metabolism.
The greatest problem with cancer is that since there are hundreds of different types of cells in the human body, there are hundreds of different types of cancers. The type of cell in which the cancer starts will generally determine the speed at which it grows and its resistance to treatment, although there are many variables involved. The location or type of cell where the cancer starts will give a cancer its name. For example, cancer developing from a skin cell is called melanoma and a cancer that starts in the lymph nodes is called lymphoma.
WHAT CAUSES CANCER?
Carcinogens are chemicals that damage cells in a way that promotes unregulated growth and other cancer-like changes. The process of cancer development is called carcinogenesis. Cancer is a disease that develops over time and can be caused by any one of over a hundred causes. As such, it is almost impossible to determine the exact cause of cancer in a person. There are many factors that are thought to increase the likelihood of developing cancer. Here are some of them.
Tobacco Smoke
Cigarettes are arguably the most preventable cause of cancer. Cigarette smoking alone is directly responsible for approximately 30% of all cancer deaths annually in the United States. Why does cigarette smoke cause cancer? Tobacco smoke contains thousands of chemical agents, including over 60 substances that are known to cause cancer. Just to list a few, cigarettes include carbon monoxide, tar, arsenic and lead.
In 2006, researchers from the University of Florida discovered that cigarette smoke can turn normal breast cells cancerous by blocking their ability to repair themselves, eventually causing tumor development. In other words, the toxins in cigarette smoke prevent a damaged cell from making repairs to itself. This explains why smoking is associated with such a high risk of cancer. The risk of developing smoking-related cancers increases with total lifetime exposure to cigarette smoke. Also, secondhand smoke significantly increases the risk of lung cancer and heart disease in non-smokers.
Diet
Even a quick Internet search will indicate the strength of evidence suggesting that diet is related to cancer risk. As a sample of the evidence to date, eating soy, chicken, olive oil or using a low-calorie or Mediterranean diet are all associated with a lower risk of cancer. More than 30% of cancers are thought to be preventable with dietary means. A diet rich in a variety of colorful fruits and vegetables, whole grains and legumes is thought to offer the body many nutrients to help fight cancer development. What should you avoid? Alcohol, aspartame and barbecued meats are on the list of foods that may increase the risk of cancer. Want an easy rule of thumb? The more processed or artificial a food, the more likely it is to cause more harm than benefits.
Ultraviolet Light
The ability of the sun to damage your skin is well known. Sunshine is made up of ultraviolet light that can damage the DNA in skin cells. The sun’s rays contain three types of ultraviolet light: UVA, UVB and UVC. UVA makes up most of the natural sunlight. UVB causes sunburns and is thought to be the main cause of skin cancer. UVC is mostly filtered out by the atmosphere of the earth and is of little concern to humans. Originally thought to be the main cause of skin cancer, UVB rays have been the focus of prevention efforts. However, new research points to UVA as a cancer-causing light as well.
The damage caused by ultraviolet light may happen years before a cancer develops. As such, avoiding too much sunlight is highly recommended. Who is most at risk? There are several factors that affect your risk from sun exposure, including how much time you spend outdoors, your natural skin color and use of sunbeds. Risk factors for skin cancer include:
• spending time outdoors
• using sunbeds
• having fair skin, hair or eyes.
As skin cancer develops slowly, you are more likely to develop it the older you become.
There are two main types of skin cancer: squamous cell cancer and basal cell cancer. Melanoma is the other form of skin cancer. Basal cell is the most common type of skin cancer; it tends to present as a bleeding or unhealing sore. It can look like psoriasis or eczema. Basal cell cancers are more likely in children with several episodes of sunburn in childhood as well as people with a history of periodical sunburns, e.g., holiday burns. Squamous cell cancer is slower growing than basal cell cancer but it is more likely to spread. This type of cancer is characterized by red, scaly skin that becomes an open sore. Squamous cell cancer is linked to an overall high level of sun exposure throughout life. As such, outdoor workers and those with epidodes of sunburn as children are at higher risk of this type of skin cancer. Melanoma is a malignant (spreading) tumor of the melanocytes which are found predominantly in skin.
Ionizing Radiation
Ionizing radiation is a known cause of cancer and other adverse effects. It is one of the most extensively studied human carcinogens and may account for about 3% of all cancers. How does it work? Ionizing radiation can remove electrons from molecules in your body, e.g., cell membranes, DNA, leaving them very unstable. The DNA in cells is particularly susceptible. Thus, ionizing radiation can change the molecular structure of a cell, which can lead to cancer development.
Where does ionizing radiation come from? There are some natural sources such as cosmic rays and radioactive substances in the earth’s crust. This “background” radiation is a small amount. Medical X-rays used at the dentist to see teeth root health, X-rays used by physicians to investigate bone health and mammograms of the breast subject the body to radiation. Uranium miners and those living in areas close to nuclear weapons tests are exposed to higher levels of radiation. Ironically, some cancer treatments include radiation therapy to help kill cancer cells. Yet the radiation itself increases the risk of cancer.
Historically, radiation was used to monitor patients with tuberculosis. The high amount of radiation in the targeted area caused a drastic increase in breast cancer rates 10 years after this method of monitoring began. History has many examples of how radiation use is strongly linked to an increase in cancer rates. Atomic bomb survivors in Japan have increased rates of leukemia and cancers of the breast, thyroid, lung, stomach and other organs, illustrating another example of how radiation causes cancer.
In general, the breast, thyroid and bone marrow are most sensitive to the effects of ionizing radiation. Avoiding unnecessary medical X-rays is one of the best ways to reduce exposure to ionizing radiation. However, in many instances, the benefits of ionizing radiation as a tool for diagnosis of various diseases and as an effective way to treat some cancers outweigh the risks.
Alcohol
Alcohol itself is not a carcinogen. However, population studies show that there is a strong link between alcohol consumption and some forms of cancer. A strong association exists between alcohol use and cancers of the esophagus, pharynx and mouth. Alcohol may also be linked with liver, breast and colorectal cancers. Together, these cancers kill more than 125,000 people a year in the United States alone. This modifiable risk factor causes over 4,000 cases of cancer each year in Canada. Reducing alcohol intake could save thousands of lives. Current data suggests that nearly 50% of cancers of the mouth, pharynx and larynx are associated with heavy drinking. Although there is no evidence that alcohol itself is a carcinogen, alcohol may act as a co-carcinogen by enhancing the carcinogenic effects of other chemicals. For example, studies indicate that alcohol enhances tobacco’s ability to stimulate tumor formation in rats. Heavy consumption of alcohol may increase the risk of cancer and is best avoided, as it has many negative effects on health.
Chemicals
There are many chemicals that have been developed since the beginning of the Industrial Revolution in the late 18th century. Each was created, as it offered a unique function superior to chemicals found in nature. Thought to be wonderful inventions, these chemicals were placed in everyday appliances, school buildings and foods. When they were found to be harmful to health, it was almost impossible to eliminate them from our environment. Despite the fact that the manufacturing of many of these chemicals has slowed or stopped, they are still present in our everyday environment, including schools, offices and public buildings. Here are some of the chemicals known today to be carcinogens:
• Asbestos is a crystal-like chemical that was developed to improve buildings. Today, asbestos is still found in the walls of many buildings. However, studies have shown an increased rate of lung cancer among workers exposed to asbestos. Those workers who smoke are at an even greater risk. When buying an older home, be sure to have a professional test it for asbestos.
• Benzene is present in crude oil and gasoline and is an important industrial chemical which is used in industry as a solvent or to make other chemicals and products such as dyes, detergents, nylon and plastics. It is found in everyday items including gasoline, paints and paint removers. Benzene is a clear, colorless and flammable liquid with a sweet odor. Research conducted since the 1980s by the National Cancer Institute has found that workers exposed to benzene, even at relatively low levels, have lower levels of white blood cells. Currently, the National Cancer Institute states that exposure to benzene may increase the risk of developing leukemia.
• Laundry Detergent and other household cleaners also contain chemicals that are suspected to be carcinogens. Trisodium nitriotriacetate (NTA) is found in many laundry soaps and is a suspected human carcinogen. Toilet bowl cleaners can contain ethoxylated nonyl phenols, which are suspected endocrine disrupters. Silica, which is present in abrasive powder cleaners, is a known carcinogen.
• Phthalates are widely used to make plastics and in personal care products. They are endocrine disrupting and medical literature suggests they may be linked to some reproductive defects in the male fetus. As many personal care products are targeted to teenage girls in puberty and women of childbearing years, phthalates are gaining attention as a possible cancer-causing chemical that should be avoided.
• Pesticides have been reviewed by European and North American studies and are linked with an increased rate of leukemia in children. Atrazine, a chemical found in household weed killers, is the most widely used herbicide in the United States. It impacts reproduction in frogs. Atrazine is banned in France, Germany, Sweden and Italy.
In a healthy body, antioxidants and a gamut of other defense systems prevent the number of carcinogens present in the body and work to prevent and repair the damage they cause. However, when these carcinogens are in the grass our children play in, in our homes and in our rivers, it can be hard to win the battle against them.
WHAT PREVENTS CANCER?
Many food groups are well known for their ability to reduce cancer risk: high intake of fruits, vegetables and flax seed (particularly the lignan fraction) and consumption of cruciferous vegetables and garlic. As well, the consumption of antioxidants such as lycopene, selenium, folic acid, vitamin B-12 and D are well known to reduce the risk of cancer.
Also, the microbes in your body and your immune system play a role in preventing and stopping carcinogens from causing cancer in your body. When we look at various populations, we see that the consumption of probiotic-containing foods reduces the rate of cancer. Animal studies have found that some probiotics can prevent or help treat tumors. How do probiotics, the bacteria that live primarily in the intestinal tract, play a role in cancer, a disease with a complicated origin? And, how do probiotics help prevent disease in organs so far away from where they live?
Knowledge to date in this area is preliminary. However, probiotics appear to have three ways to fight cancer. First, certain strains of probiotics can eliminate substances that can be turned into carcinogens and promote the development of cancer. Such a substance is called a pro-carcinogen. An example of such a substance is nitrite. Nitrites are unstable compounds or ions (e.g. NO-2). Probiotics in the intestinal tract convert pro-carcinogens like nitrites into neutral compounds. Lactobacillus acidophilus is an example of a probiotic strain that can neutralize these problem substances in your body. Other species may also have this characteristic.
Second, probiotics can stop enzymes which help turn pro-carcinogens into carcinogens. Enzymes such as b-glucuronidase and nitro-reductase are capable of such action. These enzymes are secreted by bad bacteria, such as Clostridium and Bacteriodes, which are normally found in your gut. They particularly love to live in your lower intestine. With fewer enzymes to create cancer-causing chemicals, the body is less likely to develop cancer. Lactobacillus acidophilus is particularly effective at neutralizing harmful enzymes that promote cancer development. This may be the most important contribution of probiotics to cancer prevention.
The third way probiotics appear to have anti-cancer effects in the body is less direct. We already know there is a positive interaction between probiotics and our immune system. Probiotics support and stimulate the immune system in many positive ways. However, probiotics also help the immune system by lightening its load. Probiotics promote a healthy intestinal lining. This reduces the ability of bad microbes that we eat from entering into our bloodstream. With fewer bad microbes in your blood that your immune system has to trap and eliminate, the less work it has to do. Your overworked immune system has less work to do thanks to probiotics. Thus, your immune system can focus on helping cells that are damaged and prevent these cells from becoming cancer. All in all, healthy colonies of probiotics in the intestinal tract can support the immune system, leaving it more energy and resources to focus on cancer prevention.
What Is Cancer?
Cancer is a disease in which a cell’s controlling mechanisms are changed causing it to reproduce abnormally. A healthy cell has a built-in “programmed cell death,” which will kill the cell when damage occurs. However, cancer cells turn off this cell-death signal. Cancer can develop in any one of the hundred different types of cells in the body. Cancers are named according to their location of development. For example, a cancer that develops in the colon is called colon cancer. If it moves to the liver, it is called colon cancer with liver metastases. Tumors can be either benign (non-cancerous) or malignant (cancerous). Benign tumor cells stay in one place in the body and are not usually life-threatening.
COLON CANCER
There is a wealth of indirect evidence supporting the ability of probiotics to prevent colon cancer in humans. Most of this evidence is based on laboratory studies and some on population research. Human studies will help confirm the ability of probiotics to prevent this terrible disease.
Epidemiological Study
Observing the trends in a population can also offer insight into the effects of a condition on health. These types of studies are called epidemiological studies.
When a population is studied, it is called an epidemiological observation. When scientists observed the frequency of colon cancer in the human population, they found that the consumption of fermented dairy products, mainly yogurt, may reduce the risk of colon cancer. This epidemiological observation suggests that there could be a link between consuming probiotics and a low risk of colon cancer.
The second most common cancer in both men and women in Canada is colorectal cancer.
The first time probiotics were thought to help prevent colon cancer was seen when different populations of people were compared and a difference in colon bacteria appeared to influence the risk of colon cancer. When Japanese-Hawaiians, North American Caucasians, native rural Japanese and rural native Africans patients who recently had a colon polyp removed were compared, the populations whose colons contained Lactobacillus species and Eubacterium aerofaciens had a lower risk of colon cancer. People whose colons contained bad microbes were found to have a higher risk of colon cancer. Thus it would appear that colons with lactic acid-producing bacteria (e.g., Lactobacillus species) have a lower risk of colon cancer. These good microbes must be causing positive health effects in the colon. Probiotics keep the colon healthy.
What influences the species in the colon microflora? A healthy colon contains a variety of probiotics, particularly Bifidobacterium. However, changes in intestinal microflora from eating a diet high in meat, high in fat and low in fiber; suffering from stress; or using antibiotics can result in increasing levels of bad microbes (e.g., Bacteriodes and Clostridium) and a decrease in the levels of Bifidobacterium.
Such a change to the microbes in your intestines results in an increase in enzymes that can turn pro-carcinogens into carcinogens, such as beta-glucuronidase, azoreductase, urease and nitroreductase. This creation of carcinogens increases the risk of colorectal cancer developing. Thus, theoretically by reducing the production of these enzymes by reducing the number of bad microbes in your colon, you can reduce the risk of cancer. In fact, animal studies have found that reducing the activity of these enzymes does reduce the incidence of tumors (cancer). Probiotics may be a way to reduce the presence and activity of these cancer-promoting enzymes in the colon.
Studies show that some probiotics can reduce bile salts, carcinogens and enzymes that convert pro-carcinogens into carcinogens.
Bifidobacteria probiotics may support colon health and prevent cancer development in another way. Bifidobacteria participate in the metabolism of various compounds including the omega-6 fatty acid, conjugated linoleic acid (CLA). CLA is thought to have anti-cancer effects. By helping the body work with CLA, probiotics can indirectly help reduce the risk of colorectal cancer.
Are there specific probiotic strains that are known to have anticancer effects in the colon? No, there are no known anti-cancer probiotic strains. However, specific probiotic strains have been identified in animal studies as having the ability to reduce the risk of developing colorectal cancer. B. longum and B. breve have been shown to prevent DNA damage by carcinogens. In addition, both B. longum and B. animalis can decrease the formation of lesions in the colon that commonly develop into cancer. B. longum may also have anti-tumor activity making it a great probiotic for defending against colorectal cancer. How exactly Bifidobacteria prevents colon (colorectal) cancer is not yet known. Long-term, extensive studies are required and eagerly anticipated.
Prebiotics may also help in the colon cancer battle. In the presence of the prebiotic inulin, B. longum appears to offer greater anti-cancer effects in the colon. Studies in rats have shown that when combined, B. longum and inulin reduced the formation of pre-cancerous lesions in the colon. In fact, the probiotic-prebiotic combination worked better than either one alone.
Perhaps the more prebiotics and probiotics the better? An animal study found that the probiotic-prebiotic combination of inulin, oligofructose, Lactobacilli rhamnosus and Bifidobacterium lactis (Bb12) resulted in a significantly lower number of colon tumors than in the animals not receiving the combination. It appears that a healthy population of colon microflora in the presence of prebiotics is a potentially effective way to prevent colon cancer. The symbiotic relationship between probiotics and prebiotics in the colon is well supported throughout research. Ensuring your diet offers your intestinal microflora sufficient prebiotics likely plays a very important role in human health.
Whether Lactobacillus species play a role in reducing the risk of colon cancer is not yet known. One lab study supplemented colon cancer-susceptible mice with Lactobacillus salivarius UCC118. The probiotic reduced the level of inflammation and the number of bad microbes (Clostridium perfringens). This does not mean that Lactobacilli can prevent colon cancer. More research is needed.
Can probiotics reduce cancer risk in humans? Experts are not certain. A prospective trial which is ongoing in Europe is called the European SYNCAN project. It is investigating the effect of L. rhamnosus GG and B. lactis Lb12 on colon cancer and may offer some new information as to how effective probiotics are against colon cancer. Evidence to date suggests that probiotics have protective properties against cancer. Studies have found that probiotics prevent DNA damage, which is an initiator of cancer. Some epidemiological studies suggest that consumption of fermented dairy products, which are good dietary sources of probiotics, might have protective effects against colon cancer. Thus, it is possible that using probiotics may be a natural way to decrease the risk of colon cancer.
LIVER CANCER
Liver cancer is the sixth most commonly diagnosed cancer in the world. Despite these figures, the cancer remains relatively rare, with 18,500 new cases in the United States every year, and about 3,000 in the United Kingdom. The highest incidences of liver cancer disease are found in East and Southeast Asia, particularly China.
Liver cancer is the third most common cause of death from cancer.
Hepatitis B Virus
Hepatitis B is a serious disease caused by a virus that attacks the liver. The virus, which is called hepatitis B virus, can cause lifelong infection, cirrhosis (scarring) of the liver, liver cancer, liver failure and death. About 3% to 6% of the world’s population is currently infected with the virus and up to one-third have been exposed. Symptoms of the acute illness caused by the virus include liver inflammation, vomiting and jaundice. Vaccines currently exist for this disease. Hepatitis B virus is endemic in China and Asia.
Liver cancer can have many causes. The largest risk factor is thought to be chronic hepatitis B virus infection. Consumption of foods contaminated with aflatoxin, such as peanuts, are also established causes of liver cancer. As the liver is the site of detoxification, carcinogens are metabolized there, making it a likely place for cancer development. Of note, most peanuts produced today have low levels of this toxin and pose a low risk to your health.
To investigate whether probiotics may help prevent liver cancer, researchers from the University of Kuopio selected 90 male students from the Guangdong province in China where exposure to aflatoxin-contaminated food is common. The double-blind, placebo-controlled trial assigned either placebo or two probiotic capsules per day, each containing 50 billion colony-forming units of a mixture of Lactobacillus rhamnosus LC705 and Propionibacterium freudenreichii ssp. Shermanii. The administration of probiotics led to a statistically significant decrease in the level of carcinogens in the body. The reduction was 36% at week three and 55% at week five. When the probiotic supplementation stopped, the carcinogens reappeared. In other words, the probiotics lowered carcinogens in the body, which might protect against cancer development.
Additional studies are needed; however, it appears from this preliminary research that probiotics may reduce the level of liver carcinogens. Probiotics may be beneficial when unavoidable exposures to aflatoxin and other natural and environmental carcinogens occur.
BLADDER CANCER
Bacteria live on the skin, in the mouth and in the intestinal tract. However, probiotics can affect organs away from these common habitats. For example, probiotics have the ability to affect the bladder. In particular, probiotics appear to offer anti-cancer effects for the bladder. This is important, as bladder cancer is the ninth most common cancer in men and the fourth most common cancer in women.
Bladder cancer is the ninth most common cancer in the world and is characterized by a high recurrence rate. The bladder is a sterile environment and thus is not normally inhabited by microorganisms. How can probiotics help? Preliminary research in the ability of probiotics to reduce the risk of bladder cancer is one of the most fascinating areas of this field. More research is coming in this area. There are only limited results to date.
Researchers have found that probiotics likely offer a protective effect against superficial bladder cancer. One species in particular has been the focus of research in this area: Lactobacillus casei Shirota. This particular species was first investigated due to findings from an epidemiological study which found that individuals who consumed L. casei Shirota more than once a week had a lower rate of bladder cancer. The researchers found that the ratio for superficial bladder cancer was 0.46 in people who consumed L. casei Shirota once or twice-weekly and 0.61 for those who consumed it more than three times per week. In other words, those who consumed this probiotic more than three times a week had an even lower rate of bladder cancer. As such, L. casei Shirota became a probiotic of great interest in terms of bladder health.
Researchers took this population information into the lab. As a result of clinical research that found that the consumption of L. casei
What Is Superficial Bladder Cancer?
Superficial bladder cancer is a common term used to describe a tumor or mass of cells on the surface of the bladder. This type of cancer can be removed surgically with good success rates; however, it has a high recurrence rate.
Shirota significantly reduced the recurrence of cancer in the bladder. In a clinical trial, patients who had been treated for superficial bladder cancer were given L. casei Shirota with positive results. L. casei Shirota is not thought to inhabit the bladder as it is a sterile environment. Its positive effect on the bladder occurs in the intestinal tract. The hypothesis is that L. casei Shirota binds compounds in the intestine that can cause cancer, making them unavailable, thus they cannot be absorbed into the blood, filtered by the kidneys and sent to the bladder where they cause damage. Once absorbed these cancer-causing compounds cause damage to the bladder tissue.
Do probiotics have a long-term anti-cancer effect? A year after the completion of this study, patients were contacted and researchers found that those given L. casei Shirota had only a 57% recurrence of bladder cancer, while the placebo group experienced an 83% recurrence of the disease.
Whether other strains of Lactobacilli or other probiotic species offer beneficial effects on the bladder is not yet known. It is likely, though, that other species offer beneficial effects to the bladder. Future research is needed in this area to determine what mixture of species can offer the best anti-cancer effects. All in all, it appears that probiotics are not just beneficial to the digestive tract but offer healthy benefits to organs not in the immediate proximity of the locations that the probiotics inhabit.
LUNG CANCER
There is no research suggesting that probiotics can reduce the risk of lung cancer or aid in its treatment. However, some research shows a connection between probiotic health benefits and a reduction in lung cancer growth. In September 2003, the International Journal of Oncology reported that treating lung cancer patients with vitamin K2 slowed the growth of cancer cells. Vitamin K2, or menaquinone, is found in egg yolk, butter and fermented soy foods, and despite its importance in, cancer fighting it only makes up about 10% of Western societies’ consumption of vitamin K. The other form of vitamin K, vitamin K1, or phylloquinone, is found in any green vegetables such as lettuce, broccoli and spinach, and makes up about 90% of the vitamin K in a typical Western diet. Vitamin K2 is the form that offers you the greatest health benefits. Probiotics convert vitamin K1 in the intestines into the more biologically active form called vitamin K2. As such, if you have probiotics in your intestines which ensure that vitamin K1 is converted into vitamin K2, you may reduce your risk of developing lung cancer. More research is needed in this area, but this is another example of how probiotics are more than just a digestive aid. Probiotics can improve the health of the entire body.
STOMACH CANCER
The number of people with stomach cancer has decreased in recent decades in Western society, but it is still a problem around the globe. There are two factors that play a major role in the development of stomach cancer: diet and infection with Helicobacter pylori (H. pylori) bacteria. The risk of stomach cancer is higher in those who eat a diet that is high in salted, smoked and pickled foods, which is common in areas of the world that lack refrigeration as a means of preserving food. Another potential cause of stomach cancer is H. pylori. This nasty bacteria will be discussed in full detail in Chapter 15. It is not known how H. pylori causes stomach cancer. First, it is thought that
H. pylori might enhance the production of free radicals (unstable molecules in your body that cause damage to cell DNA and can lead to cancer), increasing the number of stomach cells that have DNA damage. Second, this bacteria may change the structures of stomach cells, such as cell proteins. This may help cancer cells grow by giving them the structural changes they need to invade and thrive. Scientists are not sure that probiotics can prevent stomach cancer, but their ability to fight H. pylori may help. In Chapter 15, I will discuss more about the ability of probioitcs to fight H. pylori.
RADIATION THERAPY
Perhaps the most exciting way probiotics can help fight cancer is through its ability to promote health in people undergoing chemotherapy or radiation treatments. In 2006, Russian researchers reported the ability of a probiotic called Acilact to improve the health of mice when exposed to ionizing radiation and chemotherapy. The probiotics reduced the ability of bad microbes from invading the intestinal tract. The mice also had improvements in the health of their blood and bone marrow (blood cells are greatly affected by radiation).
Researchers then wanted to see if probiotics could reduce the risk of radiation-induced diarrhea. In 2007, Italian researchers reported that “lactic acid-producing bacteria are an easy, safe, and feasible approach to protect cancer patients against the risk of radiation-induced diarrhea.” This conclusion came from a trial involving almost 500 cancer patients who were going through radiation therapy.
Radiation therapy targets cells that reproduce quickly. This includes skin, hair and the cells lining the intestinal tract among others. Radiation causes a very immediate effect on the sensitive cells that line the intestines. The result is an unhealthy intestinal lining. Using probiotic supplements to repopulate the intestines can improve the health of the intestinal lining and prevent bad microbes from growing and causing diarrhea.
The potential for probiotics to alleviate or prevent radiation therapy- associated diarrhea is great. Patients undergoing radiation therapy suffer from many side effects. Probiotics may reduce the likelihood of diarrhea and improve the health of the intestines. This means patients can absorb more nutrients and have less intestinal discomfort and disease.
SUMMARY
Cancer is the second leading cause of death in developed countries. Adopting healthier lifestyles such as avoiding tobacco use, increasing physical activity, achieving optimal weight, improving nutrition and avoiding sun exposure can significantly reduce a person’s risk of cancer.
Over the past decade it has become clear that nutrition plays a major role in cancer. It has been estimated by the World Cancer Research Fund that 30% to 40% of all cancers can be prevented by diet, physical activity and proper body weight management. Nutrient-sparse foods such as refined flour and concentrated sugar products, low fiber intake, red meat consumption, and low omega-3 and omega-6 intake may all contribute to cancer risk.
Many nutrients and food groups are well known for their ability to reduce cancer risk: the consumption of fruits, vegetables and flax seed; cruciferous vegetables and garlic; and antioxidants such as lycopene, selenium, folic acid and vitamin B-12 and D. Probiotics, the beneficial bacteria commonly found in dairy products, are also supported as dietary elements to reduce cancer risk. Probiotics offer anti-cancer benefits including the ability to reduce pro-carcinogenic enzymes and produce short chain fatty acids which create a healthy colon pH which is associated with lower risks of cancer.
The human body was designed to be able to correct mistakes or damage in cells. Programmed cell death makes damaged cells die. Also the immune system plays a vital role in cancer prevention. A healthy immune system with sufficient resources should be able to keep the body healthy. Probiotics are well known for their ability to support the immune system and as such are likely to offer some support in the fight against cancer.
Preliminary research suggests that probiotics offer anti-cancer benefits to the human body. The risk of lung, colon, liver and bladder cancer may be reduced with the help of probiotics. Lactobacilli species have been shown in research to have anti-cancer effects on the body. Other probiotic species likely offer similar anti-cancer benefits to humans. Prebiotics may also help fight the development of cancer, particularly colon cancer. The most promising research is the ability of probiotics to improve the health of cancer patients undergoing radiation therapy. More research in the area of probiotics and cancer is needed as the use of probiotics to prevent and treat cancer holds great promise.