Nutrition and cancer - The ideal diet using the traffic light system

Tuesday 08 May 2018


Hello everyone, it is my intention going forward to write blogs on specific types of cancer and any nutritional recommendations for that particular cancer. Before I start these, I wanted to write about the ‘ideal diet’ or eating pattern that is recommended for those with cancer and beyond.

In order to do this, I have researched many different avenues so that I can pass on a really comprehensive plan. I have looked at the recommendations from the Cancer Research Fund, The Mediterranean diet, The CUP report, The Macrobiotic diet, The Rainbow diet and all about Low Glycaemic eating, amongst others.

As a result of this research I have developed a plan based on the Traffic Light System. Green for Go - choosing the foods from the green list to make up the bulk or total part of your diet. The Amber list to eat moderately or dip into occasionally, and the Red list to eat in strict moderation if at all.

It is important to remember that this plan will not suit everyone, particularly those going through treatment where they may have to modify their eating to accommodate possible side effects from treatment.

The plan can be adopted when any side effects have gone and you are ready to move forward. As always, it is important to remember that even with the best of intentions you may not be able to follow this on some days simply because it is not possible.

But if the essence of the plan can be adopted and used for the majority of the time, that would be good. Also remember that we do have high days like celebrations, birthdays, Christmas etc. and of course holidays when we want to have treats. This is perfectly acceptable and normal, but in my experience many people start to feel so much better on the Traffic Light System that treats are minimal when on holiday rather than the norm.

Here we go:

The Green List

  • Vegetables and fruits; 8-10 portions a day. Choose a variety of colours (the Rainbow Diet). Vegetables and fruits contain many compounds that support health including fibre, vitamins, minerals and phytochemicals. Many of these display anti-oxidant and anti-inflammatory properties and have been shown in laboratory conditions to also have anti-cancer properties.
  • Whole grains; whole meal bread, brown rice, oats, quinoa. These provide fibre, B vitamins and vitamin E and a range of minerals and essential fats. They also help to keep blood sugar low and stable.
  • Pulses; peas, beans and lentils. These contain some protein, a good source of fibre, vitamins and minerals particularly iron, calcium and magnesium. It is recommended to have some vegetarian days in the week and these are the foods where you would get your essential protein from. When using tinned varieties of pulses, which are perfectly acceptable and very convenient, drain and rinse before use.
  • Protein foods; Include some at each meal and with snacks, as this will help to keep blood sugar stable and keep you full longer. Oily fish, white fish, chicken, turkey, eggs, almonds, cashew nuts and seeds. Protein is so important for repair of the body and to support the immune system. Protein foods also help to prevent muscle mass loss during weight loss.
  • Healthy Fats; Especially omega 3 rich foods, nuts, seeds, oily types of fish, nut oils, seed oils, nut butters, coconut oil and avocado.
  • Herbs and spices; These have powerful health enhancing properties including anti-oxidants and anti-inflammatory. These add flavour and interest to foods. Examples include turmeric, garlic, ginger, thyme and sage. Many compounds have shown in laboratory conditions remarkable inhibitory effects on tumour growth.
  • Water; drink regularly throughout the day. Aim for 1½ litres a day.

The Amber List

  • Red Meats; Red meat can be quite hard to digest and is not good if energy is already low. Meat is however a good source of B vitamins and iron and of course protein. Try to buy good clean meat form the local butcher or farmer’s market or buy organic if the purse strings will stretch that far. These meats are less likely to be contaminated with anti-biotics or any added hormones sometimes used in intensively reared animals. It is recommended to try and restrict red meat to no more than 3 times a week, however many recommend being as vegetarian as you can, which would mean relying on pulses to get your protein rather than meat. This is of course a matter of choice, some people love meat and would miss it, so in this case moderation is the key.
  • Dairy products; Lots of different opinions on this. Many highlight the fact that dairy foods do contain hormones and growth factors found naturally in the animals the milk comes from. If you are concerned about this then try the plant based milks like almond milk or coconut milk, oatly milk or rice milk. Plant based milks are generally fortified with calcium and vitamins. When buying them avoid the sweetened varieties.

However, it is recommended that fermented milk products should be included because of their probiotic qualities. Foods like Kefir and live yogurt.

  • Caffeine; Found in coffee, tea and commercial fizzy drinks. Caffeine can stimulate the production of the stress hormone cortisol which can raise blood sugar levels and affect the immune system. If you drink decaffeinated coffee, try and buy Taylor’s as the caffeine has been removed by the Swiss water method rather through a chemical removal.
  • Soya products; Like tofu, milk and Tempeh. If these have been a regular part of your diet then it is ok to continue their use. However, research tells us that it not advisable not to introduce them after diagnosis or if on tamoxifen or other hormone suppressing drugs.
  • White carbohydrate foods; like white bread, pasta, rice and white potatoes. These when eaten can have a negative effect on our blood sugar levels making it rise. If however they are eaten with some protein rich foods this can help buffer their impact on blood sugar. For example, if you eat a jacket potato and add tuna or hummus or beans (protein foods) this will help to lessen the impact of the white potato on blood sugar levels. Another example: a curry that contains meat or beans or lentils will help to buffer the impact that white rice has on the blood sugar levels. So the rule here is if you eat a white carbohydrate then have it with some protein food.

The Red List

  • Processed cereals and sugars; These foods have very little or no nutritional value and are associated with convenience foods that contain many additives and chemicals. These foods can cause the blood sugar to rise rapidly which can have a negative effect on insulin production and the immune system.
  • Damaged Fats; These are known as Trans fats or Hydrogenated fats or any fat that is over heated or reused in cooking. They are chemically foreign to our body and can create free radicals which have a negative impact on the way the cell functions. They can damage the DNA of the cell.
  • Processed meats and fish; smoked, cured and slated all contain preservatives which are known to be carcinogenic.
  • Salt; Rock salt and Sea salt are the best to choose as they contain some minerals and are closer to our own natural salt. Salt can be hidden in many products and it is easy to have too much. This can cause an imbalance of minerals in the body, affect blood pressure, fluid retention, and can weaken cell function. It is important to read labels to check salt content.
  • Alcohol; Although red wine does contain a beneficial compound called resveratrol, to benefit from this you would have to have been drinking wine for a very long time (French Paradox). Alcohol is high in sugar, places a strain on the liver, and undermines good health.

Blog originally written by Caroline July 2017 - links updated 2021

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