How Research that Links Cancer to Foods Works

We hear everyday about new findings telling us to eat this type of food to prevent cancer or to avoid that one to better our chances for recovery. There are lists of anti-cancer foods, miracle cures, millions of advice out there. So how do we know what to believe and which recommendations to follow? As with everything in our information age, the safest way to distinguish facts from noise is to trust reputable sources whose findings are based on proven methodologies.
Now the curious mind can’t help but wonder what these methodologies are? How do scientists figure out that eating garlic is good for our bodies while we should lower our consumption of grilled bacon?
The main thing to keep in mind is that whatever methodology is used, each one has advantages and limitations. Therefore, to determine the level of evidence of a relationship between a food and cancer risk, we can not rely on a single study, nor a single method of investigation: an evaluation of all the study results available is necessary. This is why researchers publish their findings in publications like The New England Journal of Medicine (NEJM), a weekly general medical journal that publishes new medical research and review articles. This way, researchers all over the globe can compare their findings, comment and add their own results. Findings are then implemented as part of a collective scientific expertise.

This being said, here is a high level description of the different methods used worldwide to understand the link between food and cancer to help us eradicate the disease.

Cross-sectional studies: (also called "ecological studies"), which study the relationship between diet and cancer across populations. For instance, the Okinawans, residents of an idyllic island group in Japan, claim to be the longest-lived people in the world. A sample weekend breakfast consists of brown rice, miso soup with seaweed, steamed spinach and jasmine tea. In North America, a sample weekend breakfast consists of waffles, muffins, eggs, baby back bacon, sausage links, maple syrup and coffee. In stark contrast, the Okinawans have 80 percent less breast and prostate cancer and less than half the ovarian and colon cancer than North Americans.

Cohort studies: Collect data about food for a group of volunteers who will be followed for several years. If some people develop cancer, researchers can examine the specificities of their diet. This type of study can be implemented in the case of rare cancers. A cohort study is often undertaken to obtain evidence to try to refute the existence of a suspected association between cause and effect; failure to refute a hypothesis strengthens confidence in it. Crucially, the cohort is identified before the appearance of the disease under investigation. The study groups follow a group of people who do not have the disease for a period of time and see who develops the disease (new incidence).

The case-control studies: here researchers compare past food consumption data in a group of people with cancer to those of a comparable group of people (same age, same gender, same culture ...) who are cancer free. A major limitation of this type of study is the "recall bias": the participants do not necessarily remember their past eating habits or may have a distorted memory. One of the most significant triumphs of the case-control study was the demonstration of the link between tobacco smoking and lung cancer, by Sir Richard Doll and others after him. Doll was able to show a statistically significant association between the two in a large case control study. Opponents argued (correctly) for many years that this type of study cannot prove causation, but the eventual results of cohort studies confirmed the causal link which the case-control studies suggested, and it is now accepted that tobacco smoking is the cause of about 87% of all lung cancer mortality in the US.

Clinical trials: when there are strong arguments suggesting that dietary factors may reduce cancer risk, researchers can test this hypothesis in human volunteers. In practice, people involved in this type of study are divided into two groups: one group of "intervention" which is instructed to change its diet so as to adopt a habit that may reduce their risk of cancer, and a control group that does not change its habits. The researchers then studied the long-term benefits of the intervention tested.

So now you know how researchers can tell you that eating cranberries or whole grains is good for you. So before you run to the store to look for the latest fad in anti cancer food, take a minute and look at the research methodology supporting that claim. It is not to say that some findings may not have been tested yet, but it’s a good evaluation tool in the quest for healthy food to fight cancer.
For more resources about cancer treatments and patients’ wellbeing, visit our blog: http://www.lazarex.org/resources.html
By Fabienne Der Hagopian
Lazarex Senior Writer
Paris, France

Lazarex Cancer Foundation’s primary purpose is to help patients with end stage cancer get to FDA clinical trials. We provide assistance to identify their clinical trial options and the funds to help cover associated costs like travel and lodging. Many of the medical cures commonly used today were developed and approved in clinical trials. It is through Lazarex.org that patients can find life-saving solutions without waiting years for FDA approval. Articles written for Lazarex provide different perspectives and are not to be perceived as medical advice.

Excerpt: We hear everyday about new findings telling us to eat this type of food to prevent cancer or to avoid that one to better our chances for recovery. This article presents a high level description of the different methods used worldwide to understand the link between food and cancer to help us eradicate the disease.
Keywords: cancer, health, food, cancer research