Dr Francis Elegbuo of Franel Phytotherapy Clinic, Ikotun,Lagos writes that the best defence against cancer is prevention, i.e keeping ourselves as healthy as possible and eating foods that have been known to help protect our bodies.
Cancer prevention is the holy grail of medical research. Students in medical school dream of finding a cure, scientists hope their work will provide the foundation for the one true end of this disease, and patients and family members pray for a future without cancer. Until that grand discovery, we will have to count on the wisdom of our bodies and that provided by the Mother Nature.
Healthy immune systems work hard to spot and eliminate cancerous cellular mutations before the disease can begin its wild, uncontrolled growth. Prevention, then, is all about keeping ourselves as healthy as possible and eating the kinds of foods that have been shown to help protect us – right down to our cells.
What influences Cancer?
Cancer doesn’t surface overnight. It is the end point of a process that spans years or even decades. The process starts when normal body cells are damaged by a virus, radiation, toxic chemicals, inflammation, or randomly occurring errors in cells’ DNA that accumulate as we age. Every time a cell is damaged, there is the possibility that its genetic structure may mutate. Cells can handle a certain number of mutations without serious consequences, but after a certain point, the mutations change their essential nature, turning them from normal body cells into precancerous cells. This first stage of cancer development is called initiation. Precancerous cells can reside harmlessly in the body without ever progressing to full-fledged cancer, but sometimes they become activated. In this stage, called promotion, the cells begin to grow and multiply. The third stage of cancer development is called progression, when the cells multiply out of control and begin spreading.
The first step toward cancer prevention is avoiding the kinds of damage that cause mutations. Although scientists don’t have all the answers regarding what turns a precancerous cell into a cancer cell, it is widely believed that the forces behind mutations also allow the promotion and progression of cancer. The primary cancer culprits are detailed below.
Smoking: Smoking has been estimated to cause about 30 percent of all cancers in cancer patients. You probably know that smoking is linked to the risk of lung cancer, but it also increases the risk of cancers of the mouth, throat, esophagus, stomach, pancreas, kidney, bladder, and cervix. Furthermore, secondhand smoke increases the risk of cancer among people who live with smokers. Tobacco smoke contains dozens of toxins capable of damaging cells. The delicate lining of the lungs is directly exposed to the smoke, but toxins move from the lungs to the bloodstream to cells throughout the body.
Alcohol: Moderate drinking is defined as no more than two servings of alcohol per day for men and one serving per day for women. Excessive alcohol intake has been linked to an increased risk of cancer of the breast, mouth, throat, esophagus, colon, rectum, and liver. The association is especially strong for breast cancer- even one drink or less per day has been shown to increase a woman’s risk. No one is really sure what makes alcohol so dangerous, but there are theories: Alcohol itself is toxic to cells, and so are some of the by-products created when it is metabolised. Alcohol also increases hormone levels, thus heightening the risk of hormone-related cancers like breast cancer. And because alcohol makes cells more vulnerable to other cancerous compounds, smokers who drink have a tremendously increased risk of mouth and throat cancers. And the more you drink and smoke, the greater the risk. Heavy drinkers who don’t smoke have a risk of head and neck cancers that is 10 times higher than the risk for people who neither drink nor smoke. But if heavy drinkers also smoke, their risk jumps to about 150 times higher.
Radiation: It has been known for decades that radiation from excessive exposure to X-rays can cause cancer. The amount of radiation we get from medical X-rays is very small and is thought to contribute to only about one percent of cancer risk worldwide. Sunlight contains a form of radiation called ultraviolet rays, which penetrate skin cells and may cause mutations that can turn into skin cancer. Long-term, cumulative exposure to sunlight causes mainly basal cell and squamous cell carcinomas, which are types of cancer that can be disfiguring but are rarely lethal. Severe sunburns, usually in childhood, increase the risk of developing the more dangerous cancer, malignant melanoma, later in life.
Viruses and Bacteria: Infection with some strains of the human papillomavirus (HPV) can lead to cervical cancer. Hepatitis B and C bacteria can lead to liver cancer, and the H. pylori bacterium, which causes stomach ulcers, increases the risk of developing stomach cancer. Some scientists believe that these infections represent just the tip of the cancer iceberg and that many more links between cancer, viruses, and bacteria are likely to surface. Researchers don’t fully understand why some infections lead to cancer. We do know, though, that viruses can insert copies of their own DNA into normal body cells, altering the genetic structure of the cell, and those bacteria can produce toxins that may damage body cells enough to promote cancer.
Obesity: After smoking, obesity is the largest risk factor for cancer. According to the National Cancer Institute, obesity contributes to the development of cancers of the colon, endometrium, kidney, esophagus, and breast (in postmenopausal women only). Gallbladder, ovarian, and pancreatic cancers, as well as certain types of prostate cancer, may also be related, but the links are less consistent.
Since fat tissue produces and stores estrogen, postmenopausal women who are overweight can have up to twice the estrogen levels as lean women, potentially leading to the growth of estrogen-sensitive breast tumors. Other cancers may be due to the effects of high levels of insulin common among overweight people, the irritation of reflux disease, or inflammation caused by cytokines and related hormones produced in fat tissue.
Hormones: The longer women are exposed to high level of estrogen, the greater their risk of developing breast cancer. Estrogen levels climb at puberty and remain generally high until menopause, so the risk is higher for women who begin menstruating early (before age 12) or who go into menopause later in life (older than age 55). In addition, anything that increases levels of estrogen is thought to also increase the risk of breast cancer – and that includes carrying excess body fat, drinking alcohol, and taking hormone replacement therapy after menopause. High estrogen exposure is also linked to endometrial and ovarian cancers.
Eating for cancer prevention depends on knowing which foods can damage body cells and which foods can protect cells from damage.
I have heard people say that they believe cancer is unavoidable It’s true that we inherit a tendency to develop certain cancers, but scientists estimate that only about five percent of all cancers have a genetic origin. On the other hand, about 35 percent of cancers are related to nutritional factors. (To fill in the numbers, about 30 percent of cancers are thought to be related to tobacco use, and the remaining 30 percent are attributed to all remaining factors, including bacterial and viral infections, pollution, radiation, and occupational hazards.) Some foods can damage body cells, setting them up for precancerous changes, while other foods protect cells from damage. Cancer prevention depends on knowing the difference.
Foods to avoid or limit
Processed and Red Meats
A growing body of evidence links high intake of processed meats (such as bacon, salami, and bologna) and red meat in general (beef, pork, and lamb) to an increased risk of colon and rectal cancer, and possibly other cancers as well. The reasons are still being investigated, but many experts believe the high concentration of heme iron present in red meat plays a role. Heme iron is a type of highly absorbable iron found only in animal proteins. (Vegetables, legumes, fortified cereals, and other plant foods contain only nonheme iron, which doesn’t appear to carry the same risk.) Heme iron may damage the cells that line the colon, making them more susceptible to cancerous growth. Processed meats are often made from red meat and most contain chemical preservatives, such as nitrites and nitrates, which have been identified as possible cancer-causing agents. What’s more, the processes of curing, smoking, or salting meat creates additional compounds with cancer-causing potential.
It is advisable to limit your intake of processed meats, including hot dogs, ham, bacon, beef and pork sausages. If you’re a red-meat lover, enjoy fresh, unprocessed beef, lamb, or pork (preferably lean cuts) no more than twice a week. Looking on the bright side, cutting more red meat out of your diet means you’ll be more inclined to fill your plate with healthful, waistline-friendly vegetarian proteins like lentils, starchy beans, and whole soy foods.
Salty Foods: Salt is thought to increase the risk of stomach and esophageal cancers by damaging the lining of the throat and stomach. Too much damage can cause changes in DNA and increased cell growth. Also, salt allows H. pylori bacteria to thrive, which can increase the risk of stomach cancer. If you enjoy salty and pickled foods, eat them only in moderation. Limit your intake of salt itself, sauerkraut, pickles, all pickled vegetables and fish, salt-cured fish and meats, and of course all those salty processed meats listed above.
Meats Cooked at High Temperatures: Cooking meats at high temperatures produces chemicals called heterocyclic amines (HCAs), which have been linked to many cancers, including those of the colon, pancreas, bladder, prostate, and breast. The most HCAs are found in proteins (beef, pork, poultry, and fish) that have been fried, broiled, grilled, or barbecued – all cooking methods that typically use high temperatures. Roasting and baking produce fewer HCAs, and poaching, stewing, and boiling meat produce the least. There aren’t any specific guidelines about the amount of HCAs that can be considered “safe” or “dangerous.” I recommend limiting your intake of meat cooked at high heat, but there’s no reason for paranoia. If you love a good grilled steak, feel free to indulge once in a while. Just be sure to trim away excess fat before grilling and cut off charred or burned parts before eating the meat. This goes for chicken, turkey, and seafood too. To further reduce your risk of consuming harmful HCAs, marinate your meat before tossing it on the grill. Marinating meat in a flavorful liquid with plenty of herbs and spices has been shown to dramatically cut back on HCA formation, perhaps because the antioxidants in seasonings block the creation of HCAs. Also, small pieces of chicken, fish, and lean beef cook faster and spend less time on the grill, therefore producing fewer HCAs; so try cooking kebabs instead of large breasts and steaks whenever you can. In general, definitely consider cutting back if you eat beef or other grilled meats more than three times per week.
Good foods to choose
Cancer is a disease of opportunity: If a rogue cell has a chance to mutate, it may become cancerous. Along with avoiding mutation triggers, cancer prevention depends on protecting our health and putting up roadblocks to stop precancerous cells from turning bad and running amok. Our best hope is to eat a wide variety of nutrient-dense plant foods, including vegetables, fruits, starchy beans, lentils, and whole grains. Please note that although scientists typically focus on certain nutrients in relation to particular types of cancer, there are probably many beneficial interactions among the compounds in these healthy foods – and they may help prevent cancer in many areas of the body, not just the ones that are mentioned here. So, the strongest cancer-prevention plan is to eat a good mix of healthy plant foods, without focusing too strongly on any one nutrient.
Antioxidant Vitamins and Minerals
Antioxidants are your body’s version of a computer’s antivirus software. Antioxidants circulate through your cells, repairing DNA that has been damaged by harmful, reactive oxygen molecules called free radicals in much the same way that an antivirus programme combs a hard drive seeking out and restoring infected files. Left unchecked, damaged DNA may impair normal cell reproduction and growth and set in motion processes that can eventually result in cancer. For this reason, a diet that emphasi ses antioxidant-rich foods like vegetables, fruits, and whole grains may be one of your best defences against cancer. Note that the key word here is foods. Nearly two decades of disappointing research trials have taught us that you’re far better off getting your antioxidants in their natural states, not in the isolated, purified forms found in supplements. Researchers have repeatedly tested high-dose antioxidant supplements to see if they reduce cancer rates, and time and time again, supplements have shown no benefit.
