Nutrition science is an evolving field of study and it focuses on dietary concerns and health issues concerning food, eating and medicine. It is multidisciplinary in that it straddles across fields like chemistry, biology and the social sciences. Additionally, one area of research also considers our behaviour regarding food choices.

Have you come across nutritional studies that seem to conflict with one another? For instance: are eggs good or bad for us? An Associated Press article in March 2019 raised concerns about the ‘egg debate’ i.e., whether the consumption of eggs led to increased blood cholesterol and risk of heart disease or the opposite. Given the slew of different nutrition headlines, it can give rise to the perception that nutrition science is changing every day with what used to be encouraged now being met with disapproval and vice versa.

Understanding Nutrition Research

Nutrition research does not tend to be well-funded, compared to studies about cancer or other drug-related diseases which pharmaceutical companies are keen to fund. With the lack of funding, nutrition research tend to have small sample sizes which then means that researchers repeat the same small study multiple times.

Typically, if the results are aggregated in what is called a meta-analysis, then the study becomes somewhat larger and the results become more reliable. If there is an outlier in the research, i.e. someone concludes something that contradicts the commonly accepted science, then such results are outliers and the results from the meta-analysis do not really become skewed.

The problem arises when outlying nutrition research is reported as stand-alone studies, where the outlier is presented as the sole source of information that causes sensationalist headlines news. This is why it is critical to consider the size of the nutrition research and whether or not small studies have been replicated. The nutrition decisions we make cannot be influenced by just the headline nutrition news but on the weight of evidence that has been gathered over time.

Watch this YouTube video to understand why nutrition studies keep contradicting one another. “The way nutrition research is done makes it really hard to translate the results to practical advice because of imperfect comparisons”.

The Effect of Corporate Sponsors

Another problem that arises from the under-funding of nutrition research is that food companies and industry groups are often the ones who take up the slack to sponsor research. Inevitably, this creates a conflict of interest. Ultimately, the reason that food corporations sponsor research is largely for marketing purposes, rather than for the interest of public health. In this light, it is not difficult to invent a reason or a scientific basis for the research.

Overwhelmingly, -and hardly surprising-, the majority of industry-backed nutrition research is favourable to the industrial sponsors. It is a funding bias that occurs when researchers are more likely to reach conclusions that appease their funders. Yet, while it is important to be critical of corporate research (and indeed all forms of research), should we obliterate all forms of corporate research? 

Dr Katz, a medical nutritionist, argues that we should not renounce industry-funded research wholesale in a bid to protect public health. Instead, he suggests that we need to make a distinction between confluence and conflict of interest. A confluence of interest occurs when the funders’ vested interests are in line with the interest of public health. Thus, with a confluence of interest, nutritionists can seek to focus on raising the standards of industry research and to improve the way nutrition research is carried out.

Perhaps, like medical and pharmaceutical research, guidelines can be developed such that research is reliable and objective regardless of who is funding it. For instance, without the funding of pharmaceutical companies, products like antibiotics and cancer treatment drugs may not exist.

Unfortunately, if we merely axe out corporate research on the basis of the sponsors, then we may leave a lacuna in terms of the nutrition or medical research that is unable to take place. There may also be harsh critics who may be unwilling to consider the weight of the scientific evidence on the possibility that funding bias may occur. A more robust approach to research would focus on holding researchers accountable to their conclusions rather than just speaking about questions of funding.

Is Nutrition Research Futile?

Notwithstanding the problems with nutrition research, including the fact that it is heavily dependent on food surveys which are inaccurate, it is still possible to gather some fruits from nutrition research. For instance, we can consider the conclusions from meta-analyses rather than single studies. 

Furthermore, we should be cautious of studies that advise us to seek out specific foods or eliminate others. For instance, if we wanted to learn whether kale prevented cancer, we would need to force a particular sample group to only eat kale for a sustained period of time, which is clearly unrealistic! Instead of extolling the virtues of particular fruits, vegetables, meats or super-foods, a more grounded research would suggest that particular dietary patterns or configurations are more healthy than others for different purposes.

Questions for further personal evaluation: 

  1. Are your dietary choices influenced by the nutrition research that you come across? Why or why not? What influences your dietary choices?
  2. What can we do to help nutrition research become more reliable and avoid conflict of interests issues?

Useful vocabulary: 

  1. outlier’: person or thing that is atypical within a particular group or category; a statistical observation that is markedly different in value from others of the sample
  2. confluence’: a coming or flowing together, meeting or gathering at one point

Here are more related articles for further reading:

  1. Science Media Centre: Expert reactions to research on red meat and processed meat

The recommendation from the NutriRECS International Consortium for the public to continue their current level of consumption of red meat (which they state as currently estimated to be three to four portions a week) is not dissimilar to our own recommendation on red meat: that eating three or less portions of red meat a week is best for cancer prevention.

“The public could be put at risk if they interpret this new recommendation to mean we can continue eating as much red and processed meat as they like without increasing their risk of cancer.  This is not the case. The message people need to hear is that we should be eating no more than three portions of red meat a week and eat little, if any, processed meat. We stand by our rigorous research of the last 30 years and urge the public to follow the current recommendations on red and processed meat.

“It is important to remember that consumption of red and processed meat is one component of our overall diet and exercise pattern and it’s unlikely that specific foods are important single factors in causing or protecting against cancer.  Instead, different patterns of diet and physical activity throughout life combine to make you more or less susceptible to cancer.”


  1. The Washington Post: Potential for bias in research backed by pharmaceutical companies

When the company is footing the bill, the opportunities for bias are manifold: Company executives seeking to promote their drugs can design research that makes their products look better. They can select like-minded academics to perform the work. And they can run the statistics in ways that make their own drugs look better than they are. If troubling signs about a drug arise, they can steer clear of further exploration.

Maybe the most widely reported research controversy arose over the arthritis drug Vioxx, which had been featured positively in a NEJM article. The article reported the results of a trial that was funded by Merck and was co-written by two company researchers.

Five years later, journal editors reported discovering that the authors had omitted key incidences of heart troubles, creating “misleading” conclusions about the drug’s safety. Before the drug was pulled from the market, according to a review by an FDA investigator, it caused an extra 27,000 heart attacks and cardiac-related deaths.