A number of dietary habits have been linked to an increased risk for cancer. So, when it comes to making healthy food choices, and deciding which foods to eat and which ones to avoid in order to thwart cancer, there’s quite a lot to keep in mind.

Scientists know that a great many different factors contribute to cancer, and that in most instances diet is merely one of these. W also can’t ever see foods in isolation – a person’s entire diet, and each little nutrient it contains, plays a role in maintaining health and preventing cancer, or conversely triggering it.

Avoid foods that fuel obesity

There’s been a global shift in the age at which puberty starts, possibly caused by high levels of childhood overweight and obesity. In 2007, around 25% of Australian children aged 2-16 were overweight or obese. The early onset of puberty in girls – at the age of eight years on average – is believed to contribute to breast cancer in adult women.

For this reason, it’s imperative to prevent overweight and obesity in children, teenagers, pregnant women (even before they conceive) – in fact, in all women – to lower their risk of developing breast cancer. A lifelong low-fat, low-GI diet rich in protective nutrients may well be the answer to this global scourge.

Dietary factors that play a role

Based on recommendations by Michael Donaldson in an article titled “Nutrition and cancer” (2004), the following foods should be avoided if you’re set on preventing or fighting cancer:

    • High-energy, nutrient-poor foods – in other words, avoid foods and/or drinks that contribute empty calories to your diet. This includes highly processed starches like white cake flour, and foods made with it, e.g. white bread, cakes, biscuits, pies and tarts.

    • High-fat, very-high-energy foods, particularly foods rich in saturated fats and trans fats. The energy content of liquid and solid fats of all types is the highest of all the so-called macronutrients, namely 8.8 calories per gram. So, for every gram of fat you avoid, you “save” 8.8 calories while possibly avoiding exposure to dangerous, cancer-causing trans fats.

    • Limit takeaways to only once or twice a month, avoid deep-fried foods (choose grilled foods instead) and beware of takeaway outlets where the oil in the deep fryer isn’t changed regularly (if you pick up a rancid odour, stay away).

    • High-sugar foods and liquids can contribute to obesity, especially in children and teenagers. Although sugar, like all carbohydrates, has a much lower energy content than fat (3.8 kJ/g vs.8.8 calories/g), we tend to eat large quantities of sweets and sugar and consume such great volumes of sweetened cold drinks that our energy intake from sugar can quite easily exceed that of fat.

    • It goes without saying that foods and drinks that combine refined starches with sugar and fat are very high in kilojoules. These foods need to be avoided to keep weight down and prevent cancer.

    • Alcohol, which contributes 6.9 calories per gram, is the second most energy-rich macronutrient. Here in Australia, we’re all very familiar with the “beer belly” – masses of solid fat deposited in the dangerous abdominal area, which can be traced straight back to the ingestion of copious amounts of alcohol. Apart from contributing to belly fat, over-consumption of alcohol also depletes the body of protective nutrients and may replace healthy foods in the diet. In this way, it worsens vitamin and mineral deficiencies (which, in turn, may contribute to cancer).

Foods to include liberally in your diet:

    • High-fibre foods. This includes all unprocessed grains and cereals, fruit and vegetables, as well as legumes (dry, cooked or canned beans, peas, lentils and soya, and all products made with legumes such as soya mince, tofu and bean curd). The more dietary fibre a carbohydrate contains, the lower the energy content will be. Eat 6-8 portions of these foods a day.

    • Foods rich in omega-3 fatty acids such as fatty fish, flaxseed, canola, walnut and soy oils, or salmon or flaxseed oil supplements, and foods with added omega-3 fatty acids such as omega-3 eggs, milk and bread. Eat fish 2-3 times a week or take an omega-3 supplement.

    • Foods rich in phytonutrients, vitamins, minerals and trace elements. Fruit and vegetables, unprocessed grains, and legumes lead the way when it comes to providing protective nutrients that keep us healthy, boost our immune systems and potentially protect against cancer. There are many examples, but if we select lycopene, a phytonutrient that protects against prostate cancer, then fresh tomatoes and all products made from tomatoes are rich in lycopene. In particular, processed tomato products (e.g. tomato sauce, puree and paste) have a higher lycopene content because they’re more concentrated. Eat five or more servings of vegetables and fruit a day, and enjoy a portion of legumes every day.

    • Probiotics may also help you to fight cancer, particularly of the bowel. These beneficial microorganisms are found in unprocessed yoghurt and other fermented foods. Have three servings of milk and/or yoghurt every day.

The bottom line?

Follow these “rules” to give your body the best chance against cancer:

    • Use fat sparingly, and choose vegetable oils rather than hard fats.

    • Use food and drinks containing sugar sparingly.

    • Make starchy foods part of most meals.

    • Eat plenty of vegetables and fruit every day.

    • Eat dry beans, split peas, lentils and soya regularly.

    • Fish, chicken, lean meat or eggs can be eaten daily.

    • Enjoy milk and/or yoghurt every day.

If we apply the above dietary changes and combine them with a prudent lifestyle (quit smoking, exercise regularly, avoid environmental pollutants), it’s entirely possible to prevent 30 to 40% of all cancers, while keeping existing cancers at bay.

References: Donaldson MS (2004). Nutrition and cancer: A review of the evidence for an anti-cancer diet. Nutrition Journal, 3:19; Pretoria News (2013). Habitat linked to cancer. Pretoria News, Wednesday, 13 November 2013, page: 9.

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