Collection: Cancer

Cancer is a disease where some of the body’s cells grow uncontrollably. The cancer burden continues to grow globally where lung, prostate, colorectal, stomach and liver cancer are the most common types of cancer in men, while breast, colorectal, lung, cervical and thyroid cancer are the most common among women according to the WHO (World Health Organisation).

In the human body cells grow and multiply (cell division) to form new cells daily. When this cell division process breaks down, abnormal cells grow and multiply when they shouldn’t. These cells may form tumours, which are lumps of tissue that can be cancerous (malignant) or non-cancerous (benign). Cancer can start anywhere in the human body.

Benign tumours usually do not spread or invade other tissue and they can be quite large. Malignant tumours are cancerous and can spread cancer cells throughout the body, through the blood or lymphatic system, in a process known as metastasis. Cancer that begins in the breast is called primary breast cancer. Cancer that begins somewhere else in the body and spreads to the breast is known as secondary breast cancer.

There is a gene component to cancer. The body normally eliminates cells with damaged DNA before they turn cancerous. The body’s ability to eliminate these cells reduces as we age and therefore, as we age, we have a higher risk of developing cancer. Each individual’s cancer has a unique combination of genetic changes.

An unhealthy lifestyle, lack of physical activity, smoking, excessive alcohol consumption and a diet with low amounts of fruit and vegetables significantly increase an individual’s risk of developing cancer. In fact, experts estimate that the risk of developing cancer can be reduced by 30% by following a healthy lifestyle.

There is not a single food that you can eat or avoid eating to prevent, kill cancer or to reduce the risk of cancer. All nutrients work synergistically and therefore a well-balanced, nutritious diet that includes all food groups in the correct ratio is important.

Myth – Sugar feeds cancer cells

Truth – Sugar feeds ALL cells in the body, and that includes cancer cells. Glucose, the simplest sugar, is the “fuel” for our bodies. Eliminating sugar (table sugar and refined carbohydrates) from the diet and replacing it with less refined, less processed carbohydrates will improve the nutritional content of the diet and improve the immune system. Eating less refined and processed foods can assist in keeping a healthy weight, which can prevent obesity that can be a trigger for cancer.

Not eating any carbohydrates is counterproductive as carbohydrates supply the body with glucose when digested. If no glucose is supplied, the body will compensate and will break down muscle (protein) and fat to make sure that the body can still function. However, studies have suggested that the ketogenic diet combined with standard cancer therapies may have the potential to enhance antitumor effects as this diet probably creates an unfavourable metabolic environment for cancer cells, although more research is needed.

The best is to eat less refined and less processed foods as they will supply the necessary nutrients to support optimum body functions.

Myth – “Superfoods” can cure cancer

Truth – Optimum nutrient intake is important to protect and build the body. Loading up on just “superfoods” is unlikely to make a difference on its own. Enjoying a diet full of rainbow coloured fruits and vegetables, whole grains, and less processed carbohydrates, healthy fats and good choices of protein or dairy, may reduce your cancer risk. Foods like blueberries, broccoli, raspberries, and other fruits, vegetables, or spices like turmeric are seen as “superfoods”, as they have larger amounts of antioxidants and other cancer-protective properties than other food. They should be part of your daily food intake with all the other less refined, less processed foods.

Myth – Stay away from soy products

Truth – Soy is a protein and can assist in reducing the risk of losing muscle mass if incorporated into a healthy diet, especially when animal protein intake is restricted or avoided. Soy products, like tofu and soy milk, contain isoflavones. Isoflavones acts like estrogen (hormone) but has a much milder effect on the body. Research has shown that eating soy products does not affect cancer risk.

It is true that an individual with cancer or who is recovering from cancer needs good nutrition to better cope with the disease and treatment, and therefore need a variety of ALL the nutrients for recovery.

If hormonal therapy is taken to treat a hormone-receptor-positive breast cancer, there is potential concern about any phytoestrogen effects. It is advisable to consult with your registered dietitian about how much soy to eat.

Generally, it's fine to eat moderate amounts of soy foods as part of a balanced diet. One serving of soy a day is about half a cup per portion.

Processed foods such as bacon, sausages, refined sugary cereals and fizzy drinks can increase cancer risk. Excess red meat, other animal protein, animal fat and alcohol can increase cancer risk.

It is not to say that these foods on their own will increase the risk of cancer. It can rather be the lack of nutrients from food such as vegetables, fruit and unrefined starches, that is not included in the diet, that increases the risk of cancer. Processed and refined products have less nutrients than their less refined and less processed counterparts.

Overweight and inactivity

Being overweight and inactive increases the risk of lifestyle diseases such as cancer, heart disease and diabetes. According to the CDC (Centre for Disease Control), obesity in women increases the risk of endometrial, breast and colorectal cancer.

Sun exposure

The sun (and sunbeds) can also increase skin cancer (melanoma) risk due to the UV (ultra violet) light exposure. Using sun protection is of the utmost importance.

Alcohol intake

High consumption of alcohol increases the risk of cancer, especially the breast, liver, colon, rectum, mouth, pharynx, larynx and oesophagus. Binge drinking (five or more drinks per occasion for men and four or more for women) or heavy drinking (15 or more drinks per week for men and or eight or more drinks per week for women) increases the risk of cancer. The less alcohol you drink, the lower the risk of cancer.


Smoking and second-hand smoke cause about 80 to 90% of lung cancer deaths. Smoking also increases the risk of cancer of the voice box (larynx), mouth and throat, oesophagus, urinary tract (bladder), kidney, pancreas, cervix, colon, rectum, liver and stomach, as well as acute myeloid leukaemia. This includes cigarette smoking and vaping.

Low fibre intake and increased animal fat

A lack of fibre, an increased intake of processed foods and a large consumption of animal protein can also increase the risk of developing cancer. These nutrients do not stand alone in the increased risk but contribute to the overall cancer risk.

Eating a well-balanced diet during cancer treatment assists the body to recover easier and the individual to feel better. Cancer treatment can be very harsh on the body and the appropriate nutrition can increase the recovery time between treatments and can prevent the lapse in treatment as the individual is not well enough to proceed with the following treatment.

The correct nutrients are important, but also the correct timing, combination and quantity of these nutrients. This can assist in reducing side effects of the treatment, managing weight loss and maintaining muscle mass; it helps to regain strength and improves the overall ability to heal.

Balanced nutrition also assists in overall wellbeing, benefitting the body and mind.

Cancer treatment can be very challenging to the body, and it is very important to find ways to maintain a healthy food intake. The side effects of the treatment can cause changes in taste and reduce appetite. This can lead to a reduced food intake that can have a negative effect on muscle mass and recovery. Other side effects include: constipation, diarrhoea, vomiting, dry mouth, and sore mouth and throat, to name a few. Emotions can also have a negative effect on food intake.

The side effects should be addressed as soon as they appear to prevent a large impact on the nutritional status.

Nutritional intervention should be individualised and adjusted as necessary as the symptoms can vary between treatments.

Medical genetic testing is a way to look at changes (variations) in genes and to gauge an idea of what the risks are of developing cancer in your lifetime. This testing is available for some types of cancer – breast cancer, ovarian cancer, colon cancer, thyroid cancer, prostate cancer, pancreatic cancer, melanoma, sarcoma, kidney cancer and stomach cancer. Not everyone with a gene variation for a specific gene will develop cancer.

Medical genetic testing may assist in predicting your risk of a particular disease and find if you have genes that may pass increased cancer risk to your children. It will also provide information to guide your health care team.

Another type of genetic testing, Nutrigenomics, studies the interaction between genes, diet and lifestyle factors - in other words, how to live as well as one can from a health perspective. This testing provides personalised recommendations using a holistic approach to health, mental health, weight management, exercise, and skin care and provides insight into improving long term health. It can also assist in preventing and mitigating the onset of chronic disease such as cancer, as well as promoting longevity.

No genetic test can say if you will develop cancer for sure. However, it can tell you if you have a higher risk than most people.

The gut microbiota has been an area of interest in the prevention and nutrition-based treatment of chronic noncommunicable diseases (NCDs), due to the close relationship that exists between its balance or imbalance and the onset and outcome of these diseases.

Diet is a major contributor to the microbiota balance or imbalance. Regular consumption of refined, processed and high fatty foods contributes to dysbiosis (imbalance). Soluble fibre, mainly composed of inulin, oligosaccharides and pectin, is the major energy source for gut microbiota bacteria, whose fermentation in the colon forms short chain fatty acids (SCFA).

Phytochemicals, although consumed in smaller amounts than dietary fibres, also have a positive impact on the gut microbiota that contributes to good health. Even more reason to consider them and promote their dietary consumption.

Unrefined, unprocessed, fresh and rainbow coloured foods can give protection in the prevention of cancer. Vegetables, fruit and whole grains that add fibre, vitamins and minerals should be the first choice of food. When it comes to animal proteins, less animal fat and healthy fat choices, such as mono-unsaturated fats (avocado, olive oil, nuts and seeds) and lower fat choices can complement the other nutrients consumed.

A lot of colourful and less refined and less processed foods in your diet is a good start and an important focus for all individuals.

A chronic inflammatory state (oxidative stress) becomes a predisposing factor for NCDs (non-communicable diseases), including cancer. This is caused by changes or increases in free radicals which enhance cellular oxidative processes. An increase in oxidative stress can cause long-term cell damage by changing the function of the cell.

There have been more than a thousand phytochemicals discovered. Phytochemicals are plant-based bioactive compounds produced by plants for their own protection against viruses, bacteria, fungi and parasites. Phytochemicals can offer humans some of that same protection. While some phytochemicals are also vitamins and act as antioxidants, they protect our cells from damage caused by environmental toxins and the body’s natural chemical (metabolic) processes.

Fruit, vegetables, whole grains, nuts and herbs have phytochemical properties. Phytochemicals can strengthen the immune system and reduce inflammation preventing DNA damage. Phytonutrients play a role in repairing cells and slows down cancer cell growth.

Examples of phytochemicals:

  • Anthocyanidins are produced by red and purple berries.
  • Beta-carotene is found in orange and dark green, leafy vegetables.
  • Catechins are present in black grapes, apricots and strawberries.
  • Carotenoids are generally present in orange fruit and vegetables. These include: pumpkin, carrots, bell peppers, tomato, several leafy greens, pineapple, citrus fruits, papaya, mango, cape gooseberry, passionfruit, and strawberries.
  • Flavonoids are found in tea and wine, onions, apples, kale, Brussels sprouts and other cruciferous vegetables.
  • Isoflavones are found in soybeans.
  • Polyphenols are found in cloves, berries and dark chocolate.
  • Quercetin is found in coriander, onions and apples.
  • Resveratrol is present in grapes.
  • Sulforaphane is found in cruciferous vegetables: cauliflower, broccoli, cabbage and radishes.
  • Curcumin is found in turmeric and curry powder.
  • Piperine is found in white pepper.

Anthocyanins are flavonoids (plant compounds) and are water soluble pigments that are responsible for the pigmentation of anthocyanin rich fruits such as blackberries, grapes, black plums, blueberries and grains such as black rice, red rice and black soybeans. Studies have shown that anthocyanins have antimicrobial, antioxidative and anti-inflammatory properties which play a role in the prevention and treatment of many chronic diseases. It has also been found that anthocyanins have been shown to exhibit anti-carcinogenic activity against multiple cancer cell types.

The vitamin B complex category of nutrients comprises B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), and B12 (cobalamin). Each of these vitamins plays a vital role in our body, from converting food into energy to supporting the health of our skin and nervous system. Despite their collective importance, each vitamin B has unique functions and benefits, underscoring the need for a comprehensive approach to our dietary intake. B vitamins, such as folate, riboflavin, cobalamin and pyridoxine are essential for the methylation process. Adequate levels of folate and vitamin B12, in particular, are necessary for the proper execution of methylation processes, playing a significant role in preventing abnormal gene expression linked to various diseases, including cancer. Methylation is a biochemical process where a methyl group is added to DNA, impacting gene expression by regulating the activity of genes without altering the DNA sequence itself.

Catechins are a group of polyphenols which occur in different parts of a variety of plants. Sources of catechins include apples, grapes, pears, apricots, strawberries, cherries, and green tea leaves Studies have shown that catechins may stop or inhibit the growth of cancer cells.

Carotenoids are naturally occurring pigments produced by plants, algae and photosynthetic bacteria. These colourful molecules are found in yellow, orange and red colour plants, fruit and vegetables. Examples of carotenoids include α-carotene, β-carotene, β-cryptoxanthin, lycopene, lutein, zeaxanthin, violaxanthin, neoxanthain, canthaxanthin, astaxanthin, fucoxanthin and siphonaxanthin. Studies have found that carotenoids have anti-cancer activity in different cancer cells such as colon, liver, breast, prostate and cervix.

Vitamin A is available in two forms: beta-carotene (a carotenoid) is a provitamin that is converted into vitamin A in the body and vitamin A is an antioxidant that protects the body against free radicals. The richest food sources of beta-carotene include any yellow, orange and green leafy fruit and vegetables such as carrots, sweet potatoes, sweet melon, butternut, broccoli and lettuce. In general, the more intense the colour of the fruit or vegetable, the more beta-carotene it contains. Foods rich in vitamin A include sweet potatoes, leafy green vegetables, pumpkins and bell peppers.

Beta carotene supplementation has no beneficial or harmful effect on cancer incidence but it may have potentially harmful effects on lung cancer, especially for individuals who smoke. Evidence from studies has shown that supplemental intake of beta carotene in isolation is not recommended for preventing cancer and the establishment of a tolerable upper intake level of beta carotene should be considered.

Curcumin is an active component in turmeric, has powerful anti-inflammatory effects and is a very strong antioxidant. Curcumin has a low bioavailability due to its water insolubility, therefore it is important to consume a good quality supplement in the form that is better absorbed. Research has found that curcumin may prevent cancer, slow down the progression of cancer, make chemotherapy more effective and protect healthy cells from the effects of radiation therapy.

Flavonoids are phytochemical compounds found in many plants, vegetables, fruit and leaves. They provide many anticancer benefits including cancer cell apoptosis (death) and preventing cancer cell proliferation (division). Food sources of flavonoids include tea, red wine, leafy vegetables, onions, apples, berries, cherries, soybeans and citrus fruits.

Isoflavones are part of the flavonoid family of polyphenols. Fruits, vegetables, chocolate, wine, and tea are some sources of flavonoids. Many legumes contain isoflavones, but soybeans and other soy foods like tofu, miso, and tempeh are rich sources. Evidence suggests that eating a diet rich in soy foods may offer protection against certain cancers and cardiovascular disease. If hormonal therapy is taken to treat a hormone-receptor-positive breast cancer, there is potential concern about any phytoestrogen effects. It is advisable to consult with your registered dietitian about how much soy to eat.

Glutathione is a naturally occurring antioxidant which assists with the detoxification and rebuilding process in the body. This water soluble nutrient plays an important role in protecting the body against oxidative stress and supports the liver in Phase I and II detoxification processes. Glutathione is also beneficial for those with genetic changes that inhibit their own production or have a greater need for glutathione to support detoxification in the body. The liposomal form of glutathione is preferred for optimal absorption. Intravenous (IV) glutathione is an effective detoxifier and aid for cell repair and in preventing chemotherapy toxicity. It is considered a safe treatment, as there are no known side effects or interactions with other drugs.

Piperine is the compound that gives black pepper that sharp taste. Black pepper consists of 5-9% piperine. Dosages of 5-10mg of piperine are often taken together with supplements such as turmeric and resveratrol to enhance absorption.Therapeutic effects of piperine include antioxidant, anti-inflammatory, and immunomodulatory properties. This nutrient may also inhibit cancer-related molecular processes and enhance existing treatments.

Polyphenols are chemical compounds with antioxidant and anti-inflammatory properties. Polyphenol food sources include chilli peppers, whole grains, wine, berries (elderberries, blueberries, blackberries, blackcurrants), herbs and spices (cloves, peppermint, star anise), cocoa powder, nuts, flaxseeds, tea and coffee. The four types of polyphenols include phenolic acids, flavonoids, stilbenes and lignans. Polyphenols protect cells from oxidative stress, inflammation, and DNA damage due to its antioxidant properties and regulate growth of many cancer cells by blocking cell cycle progression and tumor cell division and by inducing apoptosis (cell death).

Resveratrol is a class of plant micronutrients called polyphenols. It functions as an antioxidant which helps to reduce inflammation. Food sources of resveratrol include blueberries, peanuts and in the skin of grapes (red wine). It is a very difficult nutrient to take in sufficient therapeutic levels from diet alone.Therefore supplementation with resveratrol ensures the correct amount is utilized by the body to achieve optimal benefits. The trans-resveratrol form is the more biologically active compound. Research has shown that resveratrol can act against cancer cells by activating or deactivating molecular pathways.

Sulforaphane is a phytochemical found naturally in cruciferous vegetables (broccoli, cabbage, cauliflower, broccoli sprouts and kale). This phytochemical enhances the natural detoxification process of the body. As sulforaphane neutralizes toxins, it also reduces inflammation in the body. Inflammation has been linked to several kinds of cancer. This nutrient may protect your DNA and studies have found that sulforaphane inhibits variations in DNA that may lead to cancer.

Sulforaphane is yielded when a chemical reaction occurs between Glucoraphanin (essential precursor compound) and Myrosinase (essential enzyme). It must be noted that not all supplements have the ability to yield enough sulforaphane using this chemical reaction. The bioavailability of sulforaphane is low in cruciferous plants, therefore supplementation with this phytochemical is important to optimize maximum yield.

Sulforaphene is a bioactive molecule that activates protective cellular genes, boosting the body's defense mechanisms against chronic illnesses. Daikon radish seeds release the highest levels of sulforaphene. Other cruciferous vegetables, like broccoli, also contain a similar molecule called sulforaphane. However, sulforaphane from broccoli requires the presence of an additional enzyme, myrosinase, to become bioactive. In contrast, sulforaphene from daikon radish does not require this enzyme. Both molecules function similarly in inhibiting DNA variations associated with chronic illnesses such as cancer.

Quercetin is an antioxidant flavonoid (specifically a flavonol), found in onions, grapes, berries, cherries, broccoli, and citrus fruits. It is known to have protective abilities against tissue injury induced by various drug toxicities. Quercetin, known for its antioxidant, anti-tumor and anti-inflammatory properties, has been extensively researched as a chemopreventive agent in various cancer models. A study demonstrated that a relevant dose of quercetin can effectively inhibit cell cycle progression, thereby achieving its chemopreventive effects.

Thank you to Jeske Wellmann, co-author of Eat Well Feel Well – Fighting cancer with nutrition {Honors BSc Dietetics (PU for CHE / NWU) and Postgrad Diploma in Dietetics (UP)} for your information contribution to the cancer condition. For more information on cancer, please contact your healthcare practitioner.

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