Eating well and positive lifestyle choices are an important part of reducing a person’s risk of cancer. But when it comes to food choices for people who have survived cancer, key themes surface. A healthy diet and other lifestyle changes are just as important to improve the chances of surviving cancer and reducing its chance of coming back. In this podcast, I’ll look at what the scientific evidence says about lifestyle choices in improving cancer survivability and what are the key recommendations someone with cancer should aim for.

Thanks to earlier detection and much better treatment options, cancer today is more survivable than ever. Well over half of people diagnosed and treated will be alive after 5 years. Cancer survivors are very motivated to seek information about food choices, physical activity, and dietary supplements to help improve their treatment and reduce the risk of the cancer coming back again.

If you caught my podcast last week, it was all about diet and lifestyle choices that help reduce a person’s risk of cancer. And as a recap, here are the key evidence-based recommendations but together by the World Cancer Research Fund.


The WCRF panel behind these recommendations also noted that the conclusions underpinning the cancer prevention recommendations are also likely to be relevant to cancer survivors and recommend that, as far as possible, cancer survivors aim to follow these.

With so much known about how to reduce the risk of cancer by positive lifestyle choices, the next logical step was to see how effective following the prevention guidelines could be in the much less studied area of cancer survival.

Published in the Journal of Clinical Oncology, cancer researchers used health and lifestyle information collected from a long-running observational study (Iowa Women’s Health Study). Over 2000 women with a confirmed cancer diagnosis between 1986 and 2002 were identified with lifestyle information collected both before and after the cancer diagnosis.  And I’ll link to this study in the show notes. https://ascopubs.org/doi/full/10.1200/JCO.2012.45.4462 

The research team gave each woman a numerical score based on how many of the specified WCRF cancer prevention guidelines she was following. Meeting six or more of the cancer prevention guidelines showed a clear benefit. As a group, there were a third fewer deaths from all causes in women following most of the guidelines compared to women who only met 4 or less of the guidelines.

Teasing out if any of the recommendations were more beneficial than others, the clear standout was meeting physical activity recommendations of at least 30 minutes every day. Meeting this recommendation was not only linked to lower all-cause mortality but lower risk of cancer-specific and cardiovascular disease mortality.

The area of physical activity in cancer survivors is already one with some exciting research to support a benefit in cutting the risk of cancer recurrence which I’ll touch on shortly.

The study I just profiled was a single study and was published in 2013, but it doesn’t stand alone although the research field is sparse. Only a few key cancers have been studied and results can appear contradictory. Further complicating things, some studies only looked at pre-diagnosis diet while others examined post-diagnosis diet.

With the mixed research field of diet among cancer survivors, a German research team collated together 117 studies involving over 200,000 cancer survivors into a single meta-analysis.  And I’ll link to this study in the show notes. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5181206 

What they found was perhaps not too surprising. Eating lots of vegetables and fish had a favourable link with longer survival after a diagnosis of cancer. Alcohol was linked with a worse outlook and a higher risk of cancer recurrence. Grouping together whole diets found that one type of dietary pattern stood out. Termed wholefoods, prudent or healthy depending on the study description, a common theme was a dietary pattern high in fruits, vegetables and wholegrains, but low in red processed meat, refined grains and high-fat foods. Eating close to this style of dietary pattern was linked to a 22 percent lower risk of earlier death from cancer.

The opposite of a healthy diet was labelled a Western diet, high-fat diet, high-sugar snacks diet or simply: an unhealthy diet. Made up of processed meat, refined grains and lots of added sugar, this diet was linked with a 50 percent higher mortality risk from cancer compared to similar people following a healthier diet.

Exercise

So, back to the topic of exercise in cancer survivors. Evidence continues to grow that physical activity after a cancer diagnosis is linked to a better cancer survival outlook. Several research studies are now linking regular physical activity after a cancer diagnosis with lower rates of cancer-related mortality, particularly from breast and colorectal cancer. These findings are important when you consider that thanks to earlier detection and improved treatments, more people than ever are surviving cancer.

Adding further to the evidence for the benefits of being physically active after a cancer diagnosis, United States researchers looked at the lifestyle habits of over 1000 men with cancer. All of the men were part of a long-running observational study. And I’ll link to the study in the show notes. http://journals.humankinetics.com/doi/abs/10.1123/jpah.2011-0257

What clearly stood out was the earlier age of death from cancer and heart disease in inactive men. The inactive men accumulated less than the equivalent of an hour’s walking per week compared to the very active men who were active for more than the equivalent of 10 hours walking each week.

It could be that the very inactive men were that way because of pre-existing poor health, yet when allowances were made for age, smoking, body weight, and diet, the survival benefit was still clearly in favour of the active men.

Another research study from the same journal, involving people with advanced colorectal cancer, found that those undertaking the equivalent of a brisk walk for one hour per day had half the risk of a cancer recurrence compared to inactive people. https://ascopubs.org/doi/full/10.1200/jco.2006.06.0863 

The results from the two studies in people with colorectal cancer support previous published work showing a reduction in risk of cancer recurrence with increased levels of physical activity in women with breast cancer.

Several biologic mechanisms have been proposed for the association with exercise and colorectal cancer recurrence including decreasing circulating levels of insulin and insulin-like growth factor, decreasing central deposition of adipose tissue and even a favourable effect on the gut microbiota as exercise is known to change the composition of gut bacteria independent of diet.

What this all means is that physical activity after a cancer diagnosis may offer some benefits in improving survival from the disease. Because physical activity has few downsides, it is something that all cancer survivors should aim to include more of in their lives. For a person with cancer, undertaking a new ‘fitness regime’ is something that should be undertaken after appropriate advice from a health professional.

Can you cure cancer with diet?

One final area I want to cover in today’s podcast is the area of ‘cancer cure’ diet. When a person is told they have cancer, a common reaction can be to turn away from conventional medical treatments and to seek an unproven alternative medicine therapy that offers the hope of ‘curing’ cancer. The Internet is full of very average humans promoting all manner of diet therapies that promise to cure cancer. Sadly, if a true cancer cure diet existed, all doctors and health professionals would know about it and cancer would be a thing of the past.

A scientific review of 13 ‘anti cancer’ diets has looked at how the different treatments stacked up regarding having evidence to support their claims and what downside risks they could pose. It was a congo line of the ‘usual suspects’ the Internet is awash with: raw vegetables and fruits, juicing diets, the alkaline diet, macrobiotics, Gerson therapy and ketogenic diets. There was no clinical evidence supporting any of the diets that would stand up to scrutiny as a legitimate trial for seeing if it cured cancer. Furthermore, case reports and pre-clinical data pointed to the potential of a real risk of harm from malnutrition from several of the treatments. And I’ll link to the review in the show notes https://ar.iiarjournals.org/content/34/1/39 

While seeking out unproven treatments does offer hope and give some sense of control back to the cancer sufferer, the cost can be very expensive both financially and physically and can place major strains on a person’s lifestyle and personal relationships.

Many books have been written by people who have conquered cancer using an unproven ‘cancer cure’. These are only personal accounts and there is no way of assessing if the treatment was the cause of the cure as many people successfully beat cancer without using unproven treatments. To take the opposing view, there is very little written or said about those people who embark on following these therapies and don’t have the same success – you only hear of the personal success stories – that’s what sells books and gets clicks on websites.

It is best to be cautious about unproven ‘cancer cures’ and to always seek some professional independent advice. 

Summary

So, let’s wrap all this up. Greater numbers of people are surviving cancer today than ever before. With more survivors comes a greater focus on research that spotlights key lifestyle choices that raise survival odds even higher. Dietary patterns that are closely connected to foods close to their natural state such as fruits, vegetables, fish and wholegrains, cutting back on highly processed food as well as staying active sit at the top of evidence recommendation for people with cancer to be steered towards.

So that’s it for today’s show. You can find the show notes either in the app you’re listening to this podcast on if it supports it, or else head over to my webpage www.thinkingnutrition.com.au and click on the podcast section to find this episode to read the show notes.

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I’m Tim Crowe and you’ve been listening to Thinking Nutrition.