It has become an accepted fact that the causes of many cancers and other diseases are determined to a significant extent by environmental and dietary factors, including smoking, drinking, exposure to carcinogenic and mutagenic chemicals and materials. Research and clinical evidence over the past fifty years have provided us with an abundance of proof, particularly regarding environmental causes of diseases: smoking – lung cancer and heart disease; asbestos – lung cancer; nuclear radiation – leukaemia; alcohol – liver cirrhosis; smog and environmental pollution – asthma.
During the same period, epidemiologists have been extremely busy attempting to quantify which foods and nutrients play a role in the prevention and treatment of major illnesses. Diets high in fruits and vegetables, high in fibre and low in saturated fat, have been identified as conferring significant protection against certain cancers and heart disease. However, these findings sometimes become complicated, as is the case of fat and breast cancer, when studies yield conflicting results, some implicating fat directly, others not. The difficulties in isolating specific protective and treatment-effective nutrients are considerable.
In the Research Updates of this issue of Positive Health, we report the findings of Kohlmeier et al from Berlin who found that lycopene, the major carotenoid in tomatoes, conferred an almost 50% reduction in the risk of suffering a heart attack. Gorinstein et al from Jerusalem found that moderate beer drinking over 30 days increased levels of high density lipoprotein-cholesterol (HDL-C) and significantly increased levels of vitamin E, favourable indicators of protection against coronary heart disease (CAD). Appels et al from Maastricht University found that breath therapy reduced the risk of suffering another cardiac event by 50%.
However, Braga et al from Milan could not come up with any consistent pattern of foods and breast cancer risk, analysed by age and menopausal status. Bread was related to breast cancer risk in older women, protection by fish was stronger in postmenopause, protection from raw vegetables was stronger in premenopause, unsaturated fatty acid was inversely related to risk, but more strongly in postmenopausal women.
We also publish a shortened version of Lisa Saffron's report on Organic Food and Cancer Risk, which found that organic food did not confer any greater protection from cancer than non-organic food.
It is becoming clear that the rising incidence of breast and prostate cancers, the diminution of sperm quality and the feminisation of fish in our rivers is somehow modulated by hormonal and xeno-oestrogenic chemicals which mimic hormones, in particular oestrogen, a powerful cancer promoter. Organochlorine chemicals including DDT and PCBs such as lindane and dioxins have been shown to mimic hormones, be carcinogenic and tumour promoters.
It is becoming obvious to me that simply asking people what foods they ate and then compiling statistics regarding which foods confer protection is not informative enough. Surely, researchers need to know where the food was grown, under what soil conditions, which chemicals, growth-promoting substances and fertilisers were used, to really tell the whole story. And, in today's supermarket economy, with its huge diversity of available foods, people change their diets all the time. They may be meat eaters for part of their lives, and then change to any number of diets, including vegetarian, fruitarian, macrobiotic. They may start to eat only organic produce. How is a dietary questionnaire from a limited time period going to cope with this complexity?
To really get down to the nitty gritty of what is causing cancer in 1/3 of the population, researchers will have to analyse what is really in the food. However, if we wait until large-scale research is carried out that will really discover the complete nature of the food people are eating, we may all have already succumbed to cancer.
There remains only one pragmatic option for all of us and our families, and that is to continue to put pressure on government and environmental agencies to stop polluting and adulterating our food and water supplies and to demand fresh and wholesome food.
References
1. The Ecologist. Vol 28 No. 2 Mar/Apr 1998.
2. Sketris & Farmer. Effect of Vitamin C on the excretion of Methotrexate. Cancer Treatment Reports 68(2). Feb 1984.
3. Breast Cancer by Kathy Jones. Ariadne 1998.
