Cancer is a disease where body cells multiply rapidly and without purpose. The cancer growth takes food needed by the normal cells, invades healthy tissues, and spreads to other parts of the body. It can be cured only by removal or destruction of all cancer cells.
Cancer is a largely preventable disease. The 2007 World Cancer Research Fund (WCRF) /American Institute for Cancer Research ( AICR) Report gave authoritative evidence that food, nutrition, and physical activity directly affect cancer risk.
The general recommendations of the 2007 WCRF/AICR Diet and Cancer Report are as follows:
- Body fatness: be as lean as possible within the normal range of body weight
- Physical activity: be physically active as part of everyday life
- Foods and drinks that promote weight gain: limit consumption of energy-dense foods; avoid sugary drinks.
- Plant foods: eat mostly foods of plant origin
- Animal foods: limit intake of red meat and avoid processed meat
- Alcoholic drinks: limit alcoholic drinks
- Preservation, processing, preparation: limit consumption of salt; avoid moldy cereals ( grains) or pulses( legumes)
- Dietary supplements: aim to meet nutritional needs through diet alone
- Breastfeeding: mothers to breastfeed, children to be breastfed
- Cancer survivors: follow the recommendations for cancer prevention
AICR studies have found that certain foods protect against some kinds of cancer:
- Prostate: tomatoes, watermelon, and other foods containing lycopene, selenium
- Colorectum: garlic, foods containing dietary fiber
- Stomach: garlic , onions, fruits, non-starchy vegetables
- Breast: breastfeeding one’s child
- Esophagus: foods containing beta-carotene, vitamin C, non-starchy vegetables (dark green leafy),fruits
- Mouth, pharynx, larynx: non-starchy vegetables, fruits, foods containing carotenoids
- Lung: fruits, foods containing carotenoids
- Pancreas: foods containing folate
AICR Cancer Risk Meter identifies factors that raise cancer risk:
Red meat and processed meat: colorectum
Alcoholic drinks: colorectum, breast, esophagus, mouth/pharynx/larynx, liver
Excess body fat: colorectum, breast, esophagus, endometrium, kidney, pancreas, gallbladder
Abdominal fat: colorectum, breast, endometrium, pancreas
Beta-carotene supplements: lung
Salt and salty foods: stomach
Myths about Cancer
Acidic foods can alter the body’s pH balance and promote cancer.
The unsubstantiated theory is based on lab studies that suggest cancer cells thrive in an acidic (low pH) environment, but cannot survive in alkaline (high pH) surroundings. While these findings are accurate, they apply only to cells in an isolated lab setting. Altering the cell environment of the human body to create a less-acidic, less-cancer-friendly environment is virtually impossible. Acid-base balance is tightly regulated by several mechanisms, among them kidney and respiratory functions. Even slight changes to body’s pH are life-threatening events. Patients with kidney disease and pulmonary dysfunction, for example, often rely on dialysis machines and mechanical ventilators (respectively) to avoid even small disruption of acid-base balance.
People with cancer shouldn't eat sugar, since it can cause cancer to grow faster.
Sugar doesn't make cancer grow faster. All cells, including cancer cells, depend on blood sugar (glucose) for energy. But giving more sugar to cancer cells doesn't speed their growth. Likewise, depriving cancer cells of sugar doesn't slow their growth. This misconception may be based in part on a misunderstanding of positron emission tomography (PET) scans, which use a small amount of radioactive tracer — a form of glucose. All tissues in the body absorb some of this tracer, but tissues that are using more energy , including cancer cells, absorb greater amounts. For this reason, some people have concluded that cancer cells grow faster on sugar. But this is not true.
Cancer is contagious.
There's no need to avoid someone who has cancer. One can't catch it. In fact, one’s support may never be more valuable. Though cancer itself isn't contagious, sometimes viruses, which are contagious, can lead to the development of cancer. Examples of viruses that can cause cancer include: Human papillomavirus (HPV) , a sexually transmitted disease — that can cause cervical cancer and other forms of cancer ; Hepatitis C, a virus transmitted through sexual intercourse or use of infected intravenous (IV) needles can cause liver cancer
Artificial sweeteners can increase cancer risk.
Saccharin is the oldest, and probably best known, of the artificial sweeteners. In rats, high doses of saccharin can cause the formation of bladder stones that can lead to bladder cancer. However, saccharin does not appear to cause bladder stones in humans. If saccharin does increase cancer risk in humans, it does so at doses many times greater than those typically consumed. Large population studies have not reported increases in bladder cancers among people using saccharin, and the US National Toxicology Program has removed saccharin from the list of established human carcinogens (cancer causing substances).Aspartame is a low-calorie artificial sweetener that is about 200 times sweeter than sugar. Currently there is no evidence linking the consumption of aspartame with increased cancer risk.
Grilled meats can cause cancer.
It is true that eating grilled or pan-fried meats can increase a person's risk of cancer. When meat is grilled, chemicals called heterocyclicamines, which can be harmful, are created. These chemicals are found in higher quantities when meat is well-done or burned. Experts recommend limiting the amount of grilled meat in one’s diet, and avoiding the burnt parts altogether. They also recommend marinating and precooking meats before grilling. Nonetheless, many grilled foods are safe including grilled vegetables and fruits.
Most Frequently Asked Questions
Are nutritional supplements needed in cancer prevention ?
When individual nutrients are isolated and manufactured into supplement pills, they behave differently in the body. They could overwhelm the body’s usual way of fighting the type of damage that causes disease. They could interfere with medications. Researchers are conducting studies to learn if some supplements such as low-dose antioxidants may enhance standard treatment for some types of cancer. For now, high-dose vitamin E ( greater than 400 IU) may worsen cancer outcomes or increase the risk for developing cancer. Nutritional supplement may be needed when people over the age of 50 have difficulty absorbing naturally-occurring vitamin B12 including vegetarians who consume no animal foods at all. Pregnant women have increased needs for folic acid. Individuals who are dark-skinned, rarely outdoors, live in northern latitudes or the elderly may need vitamin D. Calcium supplements may benefit people who have or are at high risk for osteoporosis. Bottom line is dietary supplements are not recommended for cancer prevention.
Are herbal supplements, including garlic, cancer preventive?
They do not need FDA approval before marketing them. FDA does not analyze the contents of herbal supplements. As a result, the content, strength, and purity of a supplement may vary among brands and even among different batches of the same brand. The words standardized, verified, or certified are not FDA-defined, hence, are meaningless claims. If the label says it is verified by the US Pharmacopeia, the product ingredients on the label do not contain toxic contaminants. However, this does not guarantee safety and effectiveness. The National Cancer Institute, does not recommend any herbal supplement for the prevention of cancer, but recognizes garlic to have potential anticancer properties. Because all garlic preparations are not the same, it is difficult to determine the exact amount of garlic that may be needed to reduce cancer risk. Garlic also acts as a natural blood thinner and, thus, should be avoided by pregnant women, people about to undergo surgery, and people taking blood thinners, such as warfarin (brand name Coumadin®).
How does drinking alcohol increase my cancer risk?
Some tissues in the body, such as the mouth and esophagus, are directly exposed to alcohol. This can cause cell damage that triggers the cancer process. The relation between alcohol and breast cancer is the fact that women metabolize alcohol more slowly than men, so alcohol stays in a woman’s bloodstream longer.
Why is diabetes linked to cancer?
Type 2 diabetes and cancer share many risk factors, including obesity, poor diet, physical inactivity. Possible mechanisms linking the two diseases include hyperinsulinemia, hyperglycemia, and inflammation. Many of these conditions relate to metabolic syndrome, a cluster of disorders that increases the risk of diabetes, heart disease, and possibly cancer.
If a research study finds something causes cancer or protects against cancer then it's true … isn't it?
To reach a definite answer on a cause of cancer, scientists need to conduct at least one, but often many, controlled studies in which half the people are exposed to a suspected carcinogen. It would be unethical to conduct such studies if the expected outcome is the development of a cancer. Consequently scientists often rely on other types of studies to decide whether chemicals or other factors cause or prevent cancer, including:
- Human observation studies
- Animal studies
Information about cancer causes and prevention should always be accessed from a reliable cancer research organisation, such as:
International Agency for Research on Cancer (IARC)- WHO
National Cancer Institute USA
Cancer Research UK
The Cancer Council Australia
World Cancer Research Fund (WCRF)
American Institute for Cancer Research (AICR)
Mayo Clinic. Popular myths about the causes of cancer. www.mayoclinic.com
American Institute for Cancer Research. www.aicr.org
National Cancer Institute Fact Sheet. Garlic and cancer prevention.
WCRF/AICR. Policy and Action for Cancer Prevention. Food, Nutrition, and Physical Activity: a Global Perspective. Washington DC. 2009