In the past few decades, a number of studies have suggested a link between dietary habits and the development of cancer. However, much of this research has been unable to move beyond observing links. Now, specialists in cancer and nutrition suggest a way forward.

For decades now, researchers have been finding links between unhealthful dietary habits and the risk of cancer development and recurrence.

However, they have not yet proved beyond a doubt that all of these links are causational.

At the same time, past findings have been convincing enough to prompt researchers to investigate these connections further.

Diet is key point of discussion in cancer prevention, as it is a modifiable factor; well-informed people can make different choices when it comes to what and how they eat, which could make a real difference to their health.

Studies from the United Kingdom have found that "nearly 4 in 10" cancer cases are preventable, as modifiable risk factors drive them.

For these reasons, specialists across many disciplines—including cancer and nutrition research—came together in December last year to discuss the interplay between diet and cancer risk.

The inaugural international Cancer Prevention and Nutrition Conference took place in London, UK, under the auspices of Ludwig Cancer Research and Cancer Research UK.

The main points the researchers discussed during this conference now appear in the journal BMC Medicine.

Old challenges vs. new methods

"While data clearly show that obesity is a major risk factor for cancer," says Bob Strausberg, deputy scientific director of the Ludwig Institute for Cancer Research, "we still have a lot to learn about how diet, physical activity, and other metabolic factors impact cancer development."

"In bringing together the most prominent experts in the field across institutions, disciplines and continents, we have worked to identify these research gaps and clarify the role of nutrition in cancer prevention," he says.

One problem that the researchers discussed at the conference was the challenges that appear in understanding whether or not nutrition directly impacts the risk of cancer and the success of the treatment.

"The complexity of the metabolic factors modulated by diet and physical activity may be a contributing factor for the lack of support for several prominent food and cancer hypotheses in large prospective studies," explain Prof. Walter Willett, from the Harvard TH Chan School of Public Health in Boston, MA, and Elio Riboli, chair in cancer epidemiology and prevention at Imperial College London in the UK.

"The current nutrition and cancer evidence base is largely observational and prone to confounding, and long term diet [information] is difficult to assess," add Prof. Richard Martin, from the University of Bristol, UK, and Prof. Edward Giovannucci, from the Harvard TH Chan School of Public Health.

Yet from the different panels, it also emerged that there may now be ways to surpass these challenges. For example, conference participants argued that they can now use new analytical methods and new means of understanding how molecular factors might influence the development of cancer.

These include such innovative methods as epigenomics, transcriptomics, metabolomics, and proteomics.

"With improved mechanisms to share data, enhanced collaboration across continents, and cross-pollination increasing among traditional [isolated fields]—the links between nutrition and cancer prevention research are potentially more understandable and actionable," writes Fiona Reddington, head of population, prevention, and behavioral research funding at Cancer Research UK.

Interdisciplinarity is the way forward

At the conference, specialists also explained that funding bodies must invest more not only in research for better cancer treatments, but also in research surrounding potential risk factors—such as aspects of nutrition and methods of cancer prevention.

"Resources are reluctantly applied to prevention, let alone early life factors that are decades removed from cancer occurrence," explain Prof. Karin Michels, from the University of California, Los Angeles, and Prof. Robert Waterland, from the Baylor College of Medicine in Houston, TX.

"We hope our pressing call to action will be heard," they add.

All the researchers involved with the conference argue that it is very important to find ways of using cancer and nutrition research to form better policies and guidelines that will make a real difference to people's lives.

To this purpose, they note that scientists must work closely with national policymakers and healthcare professionals to promote healthful, nutritious food over options that are less likely to support well-being.

"Research to inform the development of policies and interventions to improve the food environment and prioritize cancer and other noncommunicable disease prevention requires interdisciplinary collaborations," write Prof. Linda Bauld, from the University of Edinburgh in the UK, and professor emerita Hilary Powers, from the University of Sheffield, also in the UK.

Indeed, according to Strausberg and Reddington, the need for interdisciplinary approaches when it comes to delving further into the links between cancer and nutrition was a main takeaway of the inaugural conference. They conclude:

"Interdisciplinary research, incorporating disciplines such as business and marketing, political science, environmental sciences, geography, data and systems sciences, as well as simulation modeling, offers great promise."