Nutrition research, in my opinion, is not very reliable. It yields conflicting and confusing results and is not generally based on good science. I know this assessment sounds harsh, but, as a Certified Nutritionist, I spend a fair amount parsing through the latest studies and assessing their reliability.

We’ve all been subjected to the conflicting results. So we wonder “Is dairy good or bad for health? Is cholesterol evil? Does red meat kill or cure? Is the ketogenic diet a godsend or a health hazard? Can the vegan, vegetarian, pescatarian, or raw food diet extend disease-free life?”

Here’s a Solid but Impractical Protocol for Nutrition Research

In an ideal world, to understand the health impact of a given food — goji berries, for instance — an experiment would go something like this:

  • Scientists recruit 10,000 participants.
  • They include both males and females, from a range of nationalities and ethnicities.
  • The subjects are housed in a laboratory for 10 years.
  • The scientists feed each person the exact same diet for the duration of their stay, with one difference: Half of the participants consume goji berries surreptitiously — perhaps blended into a mixed fruit smoothie.
  • Alcohol and tobacco are banned for the duration of the study.
  • The participants must also exercise for the same amount of time each day.
  • Neither the researchers nor the participants are aware of who is receiving the goji berry smoothie.
  • This so-called double-blinding is vital when running clinical trials.
  • During the decade-long study, the scientists monitor the participants’ health intensively.
  • This might involve running regular blood tests and medical imaging.
  • Of course, the astronomical cost of this type of study is the very first stumbling block.

Here’s the Reality of Nutrition Research

As you might image, the optimal study cannot be conducted. It is expensive and there would be volunteers to participants. So, here’s as good as it gets:

  • Nutritional research relies on “observational studies,” in which scientists look for links between what a person consumes and their current or future state of health.
  • One issue with observational studies is the researchers’ reliance on self-reported food intake.
  • Self-reports are frequently unreliable because human recall is far from perfect.
  • While studies often ask questions about the long-term impact of a nutritional component on health, researchers tend to take dietary information at just one or two points in time.
  • In reality, people’s diets can change substantially over the course of a decade.

Other Potential Problems for Nutrition Research

There are also a number of other factors that might influence the outcome and conclusions:

  • A company or industry group may underwrite the research to benefit their bottom line.
  • Trying to investigate the healthfulness of a certain diet is complex because people on the same diet don’t eat exactly the same foods in the same amounts.
  • Zeroing in on one food may not be practical since the overall make-up of the diet might be what matters more.
  • People’s bodies react to and metabolize the same foods differently.
  • Other lifestyle factors like exercise and sleep may skew the results.

The Take-Home Message

Nutrition is a minefield of confusion. Determining what is healthful and what is not can be a challenge. We are confident that fruits and vegetables are good, so you can’t go wrong easing toward plant-based eating.  

So, what can we do? Scientists should keep improving their study methods and adding to what we already know. Consumers, the public at large, and media outlets all need to be more critical.

Overall, there are no quick answers in the world of nutrition. However, because we all need to eat, interest is unlikely to disappear, and science will continue to forge ahead.

Click here to read the full article on the reliability of nutrition research.