Nutrition and Cancer

Nutrition is the process by which the body utilizes food, and involves eating the appropriate kinds & amounts of foods for the body’s needs, digestion of foods so the body can use the nutrients, absorption & use of theses nutrients, and elimination of wastes. If there is disruption in any of these processes, it can affect nutritional status over time.
In order to provide adequate nourishment for our bodies, we need to get all the nutrients for the body’s needs. Nutrients are substances obtained from food, which provide nourishment and assists the body in its growth and development. The six nutrients are:

1.       Protein – Builds and repairs body tissues, builds antibodies to fight infection, and supplies energy,
2.       Carbohydrates – Supplies energy, helps the body to use fats and provides fibre.
3.       Fats – Supplies energy, acts as an insulator, helps the body to absorb fat soluble vitamins.
4.    Vitamins – Assists iron absorption, helps to fight infection, promotes normal growth and development, maintains healthy teeth, gums and blood vessels.
5.      Minerals – Helps build bones and teeth, promotes healthy nerves, transports oxygen to the body, and helps to prevent anemia 
6.      Water – The only nutrient that everybody needs every day to help maintain hydration, transport nutrients and waste products, aid in the regulation of body temperature and maintain blood volume.​

Overall good nutrition is important for good health, therefore eating healthy before, during and after cancer treatment can help you to feel better and stay stronger.
 
Cancer
The American Institute for Cancer Research and the World Cancer Research Fund, conducted a major review of the evidence on food, nutrition, physical activity and cancer. In its report, it defined cancer as a group of more than 100 diseases characterised by uncontrolled cellular growth due to changes in the genetic information of cells. All cancers start as a single cell that has lost control of its normal growth and processes it uses to replicate. About 5–10 per cent of cancers are hereditary, but the majority involve alterations or damage that have accumulated over time to the genetic material within cells. The causes of damage are both internal and environmental. Food, nutrition, and physical activity are important environmental factors in the development of cancer.

The report also highlighted the different cancers that can be defined by the tissues in the body that they affect or originate from. For example, approximately 85 per cent of adult cancers develop from the epithelial cells (cells that line the inner and outer surfaces of the body) of the inner and outer linings of the body are called carcinomas, glandular tissue cancers such as those of the breast are called adenocarcinomas, and cancers from bone and muscle derived from mesoderm cells (cells of the embryo that grow to form muscle, blood, bone, and connective tissue), are called sarcomas. Each type of cancer may affect the patient in different ways, but one unmistakable feature of all these diseases is unregulated cell growth and/or cell death.
 
Causes of cancer
The report further identifies that there are different types of environmental factors that are known to cause cancer, and includes some aspects of food and nutrition that are established as carcinogenic by the International Agency for Research on Cancer, tobacco smoking and its use, infectious agents, medications, radiation and industrial chemicals and some carcinogenic agents in food and drink.
 
Carcinogenic Agents in Food.
Based on the report, food may be contaminated with natural or man-made carcinogenic (cancer causing agents) toxicants. Moulds and the toxins produced by some moulds cause DNA adducts (a segment of DNA bound to a cancer-causing chemical) and are carcinogenic. Aflatoxin B, a product of the Aspergillus fungus and a common contaminant of cereals (grains) and peanuts, is an established cause of liver cancer. Some carcinogenic compounds are formed during food preparation. Heterocyclic amines (any of a family of potential carcinogens present in grilled meat)  are formed by cooking meat at high temperatures, and polycyclic aromatic hydrocarbons (chemicals that occur naturally in coal, crude oil, and gasoline) can be produced in meat and fish that has been grilled (broiled) or barbecued (charbroiled) over a direct flame. High environmental concentrations of polycyclic aromatic hydrocarbons, which also come from pollution caused by traffic and industry, can contaminate other foods such as cereals, vegetables, and fruits.
The report went on to highligh that some N-nitroso compounds are carcinogens, and are formed in foods containing added nitrates or nitrites; examples include fish and meat preserved with salting or preservatives, and smoking or drying. N-nitroso compounds are also produced endogenously (originating or produced within an organism, tissue, or cell) in the stomach and colon of people who eat large amounts of red meat or take nitrite supplements.
 
Nutrition and Cancer
In the review, it was noted that Most cancers develop to the stage of being clinically identifiable only years or decades after the initial DNA damage. There are many factors that may influence the development of cancer, and science has shown over the last 25 years that diet, physical activity, and overweight/obesity are risk factors for developing some cancers, therefore by being physically active, eating a balanced diet and maintaining a healthy weight you will help your body to resist the onset of certain cancers.

Studies over time have suggested that a diet rich in a variety of vegetables, fruits, whole grains, and legumes (peas, and beans), and low in red and, especially processed meat, can fight cancer. Many naturally occurring substances in plant foods have been identified by the scientific community that has the power to defuse potential carcinogens. Some of these nutrients and natural phytochemicals seek out toxins and move them from the body before they can cause cell damage that may lead to cancer.  Others seem to make it easier for the body to make repairs at the cellular level. Still others may help stop cancer cells from reproducing. Even after a cell begins to experience damage that can lead to cancer, what you eat and drink, and how you live can still help short-circuit the cancer process (Heal Well: Healthy Eating and Activity for Living Well – A Cancer Nutrition Guide),
 
See below the American Institute for Cancer Research’s guidelines for cancer prevention and risk reduction:

Be as lean as possible without becoming underweight - where the fat is stored is also of significance, evidence has shown that excess fat around the waist can increase your risk for developing cancer as well as other chronic diseases.

1. Be physically active for at least 30 minutes every day. Limit sedentary habits - Being active helps us avoid weight gain, keep hormone levels healthy (having high levels of some hormones can increase your cancer risk), strengthen our immune system, help keep our digestive system healthy, and allow us to eat more of the foods that contain cancer-protective nutrients – without gaining weight.
2. Avoid sugary drinks. Limit consumption of energy-dense foods (foods that are high in energy or calories but low in nutrients).
3. Eat more of a variety of vegetables, fruits, whole grains and legumes such as beans.
4. Limit consumption of red meats (such as beef, pork and lamb) and avoid processed meats.
5. If consumed at all, limit alcoholic drinks to 2 for men and 1 for women a day.
6. Limit consumption of salty foods and foods processed with salt (sodium).
7. Don't use supplements to protect against cancer.
8. It is best for mothers to breastfeed exclusively for up to 6 months and then add other liquids and foods.
9.  After treatment, cancer survivors should follow the recommendations for cancer prevention.

Resources:
​
Food Nutrition, Physical Activity, and the Prevention of Cancer: A Global Perspective
​Heal Well: A Cancer Nutrition Guide
http://www.aicr.org/assets/docs/pdf/education/heal-well-guide.pdf
http://www.aicr.org/assets/docs/pdf/reports/Second_Expert_Report.pdf
http://www.aicr.org/reduce-your-cancer-risk/recommendations-for-cancer-prevention/