Part 1 of our look at the recent research into diet, cancer prevention and recovery

By Aileen Burford-Mason, PhD

Thirty years ago, when it was first proposed that poor diets were responsible for 60 percent of cancers in women and 40 percent in men, little was known about which components of diet might be protective. But recent research has begun to clarify patterns of eating that increase the risk of cancers, including breast, prostate, colorectal, melanoma and kidney cancer. 

Prudent versus Western Diets

Long-term follow-up studies at Harvard have identified two dietary patterns that seem to have opposite effects on disease risk. The first is the Western Diet, high in red meat, refined grains, French fries, high fat dairy products, sweets and desserts. The other, rich in fruits, vegetables, fish, poultry and whole grains is called the Prudent Diet, because it appears to reduce the risk of most common diseases, including cancer.

The Western diet has had an unfortunate effect on the health of nations. In a World Health Organization (WHO) report from more than a decade ago, these links were evident, stating “world-wide, the adoption of this diet has been accompanied by a major increase in coronary heart disease, stroke, various cancers, diabetes and other chronic diseases.”

Our current narrow focus on increased food production at any price has meant concentrating on quantity rather than quality. Cheap, tasty food is readily available. Unfortunately, most of it falls into the Western rather than the Prudent dietary category.

Diets and disease 

Sir Roger McCarrison, MD, the renowned Oxford scholar and nutritionist, examined patterns of disease in relation to diet. His studies in India in the early 20th century showed cancer was relatively unknown there in certain populations. He suggested that its increasing prevalence in industrial societies was due to defective diets, caused by the industrialization of our food supply. He criticized the universal consumption in Britain and North America of refined white flour, and the substitution of food that was canned, preserved, artificially sweetened or otherwise doctored, instead of fresh natural food. Such food, he argued, could not provide the basic nutritional elements required for the body to function. “And what is ‘nutrition’?” he wrote in an editorial in the British Medical Journal in 1936. “It is not merely ‘food’ nor ‘that which nourishes,’ as some lay dictionaries define it. It consists in the taking in and assimilation through chemical changes – metabolism – of materials with which the tissues of the body are built up, their waste repaired, and their deterioration prevented; by which the processes of the body are regulated and coordinated, from which energy is liberated for the internal and external work of the body.”

Today we appear to have lost sight of the fact that the “materials” with which the tissues of the body are built up, repaired and maintained are the essential nutrients – the vitamins, minerals, essential fatty acids and essential amino acids. These are as important today as they were when McCarrison was writing. 

Fresh, natural food:
Vegetables top the list ! McCarrison knew that vegetables and fruit were a critical part of a healthy diet because they contained fibre, vitamins and minerals. He did not live to see the explosion of research into other chemical constituents of vegetables called phytochemicals. It is the phytochemicals of fruits and vegetables that are turning out to be the main story in cancer prevention. 

Phytochemicals are the molecular constituents of herbs, spices, fruits and vegetables that give them their colour, smell and taste. These chemicals protect the health of the plant, and when we eat them we gain some of that protection. Phytochemicals are, for example, natural antimicrobials. Garlic is as strong an antibiotic in the laboratory as penicillin. It is also anti-viral, anti-fungal and even anti-histamine. The colour pigments of plants are antioxidants working with vitamins A, C and E, and the minerals, selenium and manganese to suppress free radicals – those damaging oxygen molecules produced by normal metabolism, but increased by, age, exercise, stress, drugs, infection and other illness. Excess free radicals damage DNA, possibly setting in motion the genetic damage underlying tumour development.

Maxing out on phytochemicals

To be prevention-ready, plant foods should dominate our eating. And no, five-a-day is not enough. In fact, five a day was ever only appropriate for children between the ages of two-to-six years. Try 10-to-14 servings of vegetables and fruit combined, depending on your size and activity level.

One serving is equal to:

   • 1/2 cup (125ml) raw or cooked vegetables, legumes or fruit (berries, cantaloupe, etc.)

   • 1 medium-sized whole vegetable (tomato, carrot, etc.) 

   • 1 medium-sized piece of fruit (apple, pear, orange, etc.)

   • 1/2 cup (125ml) vegetable juice 

   • 1 cup (250ml) raw leafy salad greens

It is important to remember that phytochemicals are fat soluble. Including a small amount of fat with a phytochemical-rich meal or snack can dramatically increase phytochemical absorption – anything from five to 15-fold. In practice, this means you need an oil-based dressing on your salad or butter on your spinach. A glass of vegetable juice can deliver the equivalent of three servings of vegetables, but you will absorb many times more phytochemicals from it if you drink it with a square of cheese, or mix in some flax seed oil or a dollop of full fat plain yogurt. 

Stay tuned next issue as we continue uncovering these good-for-you foods.