How to Prevent Cancer through Diet and Nutrition
The dictum "You are what you eat" may be an old one, but research studies in diet and nutrition prove it to be true. The link between dietary habits and the risk of the development of cancer has been supported through several clinical studies. Dietary elements have a role to play in not only the incidence and prevalence of certain cancers, but they also contribute to determining the biological and genetic course of particular types of cancer.
Cancer is a multifactorial and complex disease that impacts the state of the body. That is why cancer is identified in various variations when it comes to representing itself. While factors like genetics may not be in your control, your dietary habits certainly are.
Dietary factors have been known to affect the various phases of cancer. The role played by genetic pathways as regards to cell growth, and the ongoing parallel response of hormones and chemicals in the body has revealed how dietary components may have an impact on cancer prevention and control via molecular targets.
The more we understand the relationship between the unique cellular behaviors in combination with the molecular targets of nutrients, the more closely we will determine the role of diet and nutrition for cancer prevention.
The Background Between Cancer and Food
Food is way more than a life staple. The perception that dietary habits influence the incidence and prevalence of cancer, factors affect some 60% in women, and 40% in men (Wydner & Gori, 1977) has grown in interest over the last three decades. It is no wonder that today's millennials have adopted an array of dietary lifestyles, each with their own claims of delivering unmatched health benefits.
Nutritional genomics has contributed a pivotal role in this regard. Researchers have critically analyzed the physiological importance of nutrients and the body's response to it—for example, the role of diet in prostate cancer.¹
The fact that nutritional genomics² is an established field of study loudly advocates the role of diet and nutrition for cancer prevention. Dietary components are biologically active, and they exert a biological response within the cells via interaction with signature molecular targets.
At the same time, evolving research in diet and nutrition has helped erase fads and fables. One may observe disclaimers like 'may cause cancer' on different food labels of coffee, non-nutritive sweeteners & sugar substitutes, salt, etc., or claims like 'helps prevent cancer' on certain dietary supplements and vitamins. Be wary that all is not what it seems.
Nonetheless, the subject matter is not easily dispensed at either end. There is a lot that needs to be unearthed through significant research.
The Diet Cause and Effect
Nutritional genomics utilizes functional genomic technologies of high-quality to define the cell-nutrient interactions. Though in infancy, the scope of application of nutritional genomics is limitless as far as cancer prevention is concerned.
So far, about five hundred dietary elements have been identified that influence or modify cancer protocols in cells. These elements include allelochemicals from plant sources as well as zoochemical from animal-based food. Some of the mechanisms³ in which the dietary nutrients may contribute to cancer prevention include the following:
1. Prevent genetic damage caused by endogenous and exogenous agents through:
Blocking the uptake of carcinogens by cells.
Slowing down the activation of cancer-causing agents.
Increasing the detoxification process.
Scavenging free oxygen radicals.
Preventing DNA binding of carcinogens.
2. Stimulate the repair of structural and functional genetic defects through:
Enhancing endogenous repair.
Reestablishing proper methylation within cells.
3. Elimination of damaged or cloned cells through:
Promoting apoptosis.
Supporting cellular differentiation.
Enhancing immune-surveillance.
4. Suppression of cancer cell growth and clonal evolution through:
Slowing or stopping the proliferation.
Retarding angiogenesis.
Inhibiting invasion.
A Diet and Nutrition Strategy for Cancer Prevention
Poor dietary habits⁵ are responsible for about 30% of all cancers. Out of these, 70% of cancers are related to the gastrointestinal tract.
The good news is; acceptable dietary practices and moderate exercise pair up to reduce the morbidity and mortality rate in cancer patients. According to WHO, “between 30–50% of cancers can currently be prevented by avoiding risk factors and implementing existing evidence-based prevention strategies.”⁶
According to The American Cancer Society, about 18% of all diagnosed cancer cases in the US are related to “excess body weight, physical inactivity, excess alcohol consumption, or poor nutrition.” As already said, these factors are controllable and manageable. The American Cancer Society (ACS) Guidelines for Cancer Prevention (2012) echoes the same conclusions.⁷ The highlights of the guidelines include:
Keeping the weight in the healthy range and avoiding weight gain in adult life.
Consume nutrient-dense food, avoid calorie-rich foods.
Include assorted vegetables belonging to dark green, red and orange varieties, fiber-rich legumes (beans and peas).
Eat fruits, especially whole ones.
Include more of whole grains.
Avoid red meat and processed meat.
Cut back on Sugar-laden foods and drinks.
Remove highly refined grains and other processed foods.
Avoid alcohol.
Consume small portions of meals but in frequency.
“Include assorted vegetables belonging to dark green, red and orange varieties, fiber-rich legumes (beans and peas).”
It should be considered that the prevalence and incidence of certain cancers differ within different geographical locales, observations are mainly observed with migrating populations.
Many studies showed the incidence of prostate cancer was 25 times lower in Asians. A similar situation was seen in breast cancer, the incidence of which was ten times lower in Asians than Western countries. ¹
Similarly, the effect of lifestyle factors, including dietary factors, was observed in a study involving monozygotic twins who have the same genetic make-up. In this specific case, only 15% of the cancer cases were due to genetic factors.²
Both of the above observations show that factors like dietary lifestyle have a pronounced effect on the incidence and prevalence of cancer in addition to genetics.
Know Your Risk
Core Nutrients for Cancer Prevention
Eating certain kinds of food can increase or decrease the risk of cancer. Switching from precarious food consumption to responsible eating habits go a long way in disease prevention, and improving prognosis in cancer patients.
Here is a list of nutrients that have been shown in various studies to prevent cancer:
Phytonutrients
These plant-based food elements include carotenoids or carotenes (α-carotene, β-carotene, lycopene, lutein, and kryptoxanthin), polyphenols, and allium compounds.
A list of promising phytonutrients in this regard include dithiolthiones, isothiocyanates, indole-32-carbinol, allium compounds, isoflavones, protease inhibitors, saponins, phytosterols, inositol hexaphosphate, limonene, lutein, folic acid, beta carotene (and other carotenoids), lycopene, selenium, flavonoids, and so on.³
Carotenes are found in colorful and dark-green vegetables while the polyphenols are found in herbs, spices, vegetables, tea, coffee, chocolate, nuts, apples, onions, and berries.
Allium
Chives, garlic, leeks, and onions contain allium compounds. They are specifically found to exert protective effects against stomach⁴ and colorectal cancers⁵ and prostate cancer.⁶
Antioxidants
Antioxidants can combat cell damage. Free radicals are produced as a result of many chemical reactions in the body. These free radicals are highly reactive, and they cause cellular damage and inflammation, root causes of chronic disease as cancer.
Beta carotene, selenium, and vitamins C and E are some of the primary antioxidants present in our food. Green tea contains a flavanol, epigallocatechin-3-gallate (EGCG). It can inhibit metalloproteinases. Many other herbal ingredients also make it to the list of antioxidants and need to be reviewed for use individually.⁷
Dietary Fiber
Foods rich in dietary fiber includes whole grains and seeds (barley, oats, Kamut, spelt, bulgur, corn, psyllium, and rye), bread and pasta made out of whole grains, legumes, and pulses (beans, lentils, and split peas) and other vegetables and fruits.
Fiber adds bulk to our food and helps in the speedy exit of food through the digestive tract. It also helps to maintain and preserve the gut's microbiome activity, which is imperative in lowering cancer risk.
Vitamins and Minerals
These include calcium, iodine, vitamins A, D, K, and B vitamins. One of the prominent mineral in this regard is selenium. Its amazing functions are listed in a fact sheet printed by the Arizona Cancer Center.⁸
Some of the best plant-based selenium sources include whole grains and legumes grown in selenium-rich soil, Brazil nuts, nutritional yeast, brewers yeast, and sunflower seeds.
Omega-3 Fatty Acids
Research studies in animals have shown that reduced or insufficient intake of omega-3 fatty acids (alpha-linolenic acid, EPA, DHA) increased cancer risk. The increased cancer-risk was specifically regarding breast cancer in women, but would likely apply to other cancers as well. It was found that a higher omega-3 to omega-6 fatty acid level worked as a protective measure against breast cancer.⁹
Reduction of Cancers
Consumption of plant-based food is linked to lower the risk of some specific types of cancer, including:
Cancers of head and neck regions (oral and pharyngeal cancer)
Esophageal cancer
Stomach cancer
Lung cancer
Pancreatic cancer
Prostate cancer
Colon cancer
Endometrial cancer
These observations are consistent with reports funded by the American Institute of Cancer Research (AICR) and World Cancer Research Fund (WCRF).
The observations suggest that different phytonutrients present in fruits and vegetables work together to ward off the cancer risk posed by certain foods.
The result of consistent phytonutrients involves hormone regulation in one’s body, slowing down cancerous cells' growth, or cutting back on intracellular inflammatory processes responsible for cancer cell proliferation. Some phytonutrients regulate the production of enzymes known for their anti-cancerous effects. Phytonutrients found in cruciferous vegetables like cabbage, broccoli, and brussel sprouts are specifically known to reduce bladder¹⁰ and prostate cancer.¹¹
“Research studies in animals have shown that reduced or insufficient intake of omega-3 fatty acids (alpha-linolenic acid, EPA, DHA) increased cancer risk.” Eating most fresh or salt water fish regularly will fill this need.
Healthy dietary habits and routines are imperative to warding off chronic diseases, including cancer. A diet primarily sourced from plants with healthy proteins and fats as add-ons are tools to preventing cancer risks of diverse varieties. Increment it with supplements like probiotics, selenium, Vitamin D, Omega-3, folic acid, and, if possible oral enzymes, and your chances of developing cancer due to dietary factors may remain at bay.
Figure Out Your Cancer Risk
Sources
1. Willett WC. Diet and cancer. Oncologist. 2002;5:393–404. [PubMed] [Google Scholar]
2. Lichtenstein P, Holm NV, Verkasalo PK, Iliadou A, Kaprio J, Koskenvuo M, et al. Environmental and heritable factors in the causation of cancer—analyses of cohorts of twins from Sweden, Denmark, and Finland. N Engl J Med. 2000;343:78–85. [PubMed] [Google Scholar]
3. Steinmetz KA, Potter JD. Vegetables, fruit, and cancer prevention: a review. J Am Diet Assoc. 1996;96:1027–1039. [PubMed] [Google Scholar]
4. Fleischauer AT, Poole C, Arab L. Garlic consumption and cancer prevention: meta-analyses of colorectal and stomach cancers. Am J Clin Nutr. 2000;72:1047–1052. [PubMed] [Google Scholar]
5. Fleischauer AT, Arab L. Garlic and cancer: a critical review of the epidemiologic literature. J Nutr. 2001;131:1032S–1040S. [PubMed] [Google Scholar]
6. Hsing AW, Chokkalingam AP, Gao YT, Madigan MP, Deng J, Gridley G, Fraumeni JF Jr. Allium vegetables and risk of prostate cancer: a population-based study. J Natl Cancer Inst. 2002;94:1648–1651. [PubMed] [Google Scholar]
7. Mukhtar H, Ahmad N. Tea polyphenols: prevention of cancer and optimizing health. Am J Clin Nutr. 2000;71:1703S–1694S. discussion 1703S-1694S. [PubMed] [Google Scholar]
8. Selenium Information Sheet. http://www.selenium.arizona.edu/INFOse.htm
9. Bernard-Gallon DJ, Vissac-Sabatier C, Antoine-Vincent D, Rio PG, Maurizis JC, Fustier P, Bignon YJ. Differential effects of n-3 and n-6 polyunsaturated fatty acids on BRCA1 and BRCA2 gene expression in breast cell lines. Br J Nutr. 2002;87:281–289. [PubMed] [Google Scholar]
10. Michaud DS, Spiegelman D, Clinton SK, Rimm EB, Willett WC, Giovannucci EL. Fruit and vegetable intake and incidence of bladder cancer in a male prospective cohort. J Natl Cancer Inst. 1999;91:605–613. [PubMed] [Google Scholar]
11. Cohen JH, Kristal AR, Stanford JL. Fruit and vegetable intakes and prostate cancer risk. J Natl Cancer Inst. 2000;92:61–68. [PubMed] [Google Scholar]