“It’s in my genes”. “My dad had bowel cancer so I’ll probably get it too”. These are comments most healthcare workers will have heard at some stage in their careers. However, we know this is not the case, thanks to knowledge gleaned from epigenetics. This is the fascinating science of how these risk factors can turn on or turn off cancer gene expression.
New Zealand has the second highest cancer rate in the developed world at 438 per 100,000 people. With 30-50% of us expected to get cancer in our lifetime, there needs to be much more public awareness of modifiable factors.
As much as the above statistics are frightening, even more disturbing is the increase in cancer incidence. Researchers have recently said that the rate of some cancers have doubled and even quadrupled in the world over the past 100-150 years. Even worse, the increased rates seem to be occurring in younger and younger people.
Looking at GI tract cancers alone, according to the American Cancer Society, “by 2030 the incidence rates among people ages 20–34 years will increase by 90% for colon cancer and by 124.2% for rectal cancer. Among people aged 35–49 years, they predict the incidence rates will increase by 27.7% for colon cancer and by 46% for rectal cancer.”
What is the reason for these startling statistics? Dr McCully, from the World Cancer Research Fund states: “The increasing cancer burden is due to several factors, including population growth and ageing as well as the changing prevalence of certain causes of cancer linked to social and economic development including diet, nutrition and physical activity.”
There is also, of course, an element of modern medicine diagnosing cancer earlier, but this is a small factor in the increased rates of cancer. Another interesting factor is what’s termed as ‘relaxed natural selection’, where people with cancer are surviving longer, thanks to modern medicine. This means that the cancer genes that were turned on by people’s diet and lifestyle are being passed from one generation to the next.
Only 5–10% of all cancer cases can be attributed to genetic defects, whereas the remaining 90–95% are related to the environment and lifestyle, with inflammation being the link between the agents/factors that cause cancer and the agents that prevent it. Specifically, the following modifiable risk factors for cancer include:
- metabolic state
- inflammatory state and immune function
- nutrients, energy intake, phytochemicals, other food components, alcohol, physical activity
- food contaminants
- viruses, chronic infections
- UV radiation
- environmental carcinogens
- other environmental factors, including some medications.
So how do we reduce our chance of a cancer diagnosis?
- Be a healthy weight.
- Be physically active.
- Eat a diet rich in (ideally organic) plant-based foods.
- Limit consumption of processed foods high in fat, starches or sugars.
- Limit consumption of red meat, and particularly processed meat.
- Limit consumption of sugar-sweetened drinks.
- Limit alcohol consumption.
- Avoid smoking.
- For mothers: breastfeed your baby, if you can.
- Limit exposure to environmental carcinogens.
So please spread the message now, to those patients who think that a cancer diagnosis is inevitable for them, about the science of epigenetics!
Dr Tracy Chandler BSc (Hons) MBChB FRNZCGP FNZSCM, PGDipSEM, Cert Dermoscopy, Cert Homeopathy, MACNEM member, gained her degree in England and worked as a GP in Timaru before doing postgraduate training in sports, skin and integrative medicine.
She specialised in integrative (wellness) medicine in line with her increasing interest in the impact of nutrition and environment on health and wellbeing.