The Complexity of Human Nutrition

With the worldwide web, it has never been easier to find information on achieving sustainable levels of health and wellness, as well as managing chronic disease. Thanks to the internet and the ongoing efforts of scientists, medical researchers, and healthcare professionals, the general public has access to a broad body of knowledge when it comes to proper exercise, lifestyle choices, and nutrition.

In the field of biochemistry, metabolism, and nutrition we have gained an in-depth understanding of human biological processes, and the biochemical intake necessary to keep those processes functioning optimally. Interest in nutrition is at an all-time high, with a full gamut of dietary models being extolled as the best, correct or right diet approach. Followers often argue about the "good, better, best" diet with the same level of passion found in political and religious debates. My colleagues and I joke about how there are now three topics of discussion to avoid: politics, religion, and nutrition!

Humor aside, the question remains ...

As with most things in life, the answer is clothed in shades of gray rather than black and white. While our bodies have a uniform need for proteins, carbohydrates, vitamins, minerals, etc., the way our bodies process and assimilate them varies greatly from person to person based on gender, activity, culture, metabolic function, exercise, work and other elements of the lifestyle we live. Our nutritional needs also change significantly as we age. These variables can throw a serious wrench in the researches of dieticians, nutritionists, and food scientists, as well as undercut the claims of one diet over another.

This conundrum was highlighted brilliantly in a fact-checked February 2020 article by Tim Newman of MedicalNewsToday.com, titled "Why Is Nutrition So Hard to Study?" "Nutrition is wrapped in multiple confusions," Newman writes. "Why is it so hard to determine whether a food is good or bad for health?"

He goes on to list a number of factors ...

A changing world

Newman observes: "Although the water is muddy and difficult to traverse, there have been substantial victories in the field of nutrition research. For instance, scientists have determined that vitamin C prevents scurvy, that beriberi develops due to a thiamine deficiency, and that vitamin D deficiency causes rickets." However, he notes that in other areas of nutrition research "the picture is rarely so clear-cut. This is especially true when investigating conditions wherein multiple factors are at play, such as obesity, osteoporosis, diabetes, or heart disease."

In lieu of perfection

As multiple factors, including cost and ethical concerns, make conducting a "perfect" nutritional study impossible, "Nutritional research has to make some concessions." While observational studies have proven to be valuable, they can be problematic for several reasons, including the inconsistency of participant self-reporting. "The issues associated with measuring nutrient intake are so ingrained that some authors have referred to self-reporting as a pseudoscience."

Diving into complexity

As mentioned earlier, individual differences in food assimilation can stymie the efforts of researchers to find a clear cut answer. "There are so many variables to take into account that even when a study does find a statistically significant result, it is difficult to determine if it actually came from the food under investigation. Of course, humans are just as diverse as the foods they consume. Eating a single peanut might provide one person with beneficial nutrients, while that same peanut could be fatal for someone with an allergy."

The scourge of confounding variables

It is very easy to conflate correlation with causation when it comes to associating a particular nutritional outcome with the consumption of a particular food, neglecting the influence of other possible variables at work. As an example, Newman gives a hypothetical study regarding spinach consumption and increased lifespan:

"People who eat a great deal of spinach live for 5 years longer than people who eat no spinach. From that result, one might quickly conclude that spinach increases life span…In this case, the extended life span might not be due to the spinach alone; someone who eats a lot of spinach might also eat a lot of other vegetables. Conversely, someone who eats no spinach might eat fewer vegetables overall. Also, someone who regularly eats vegetables is possibly more likely to indulge in other healthful pastimes, such as exercise. Someone who never eats spinach might, perhaps, be less inclined to work out."

These factors serve as a sobering reminder that nutrition is far from an exact science, underscoring the need to continually evolve research standards and keep a healthy sense of skepticism regarding the alleged supremacy of certain diets over others. Newman concludes: "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."

In addition

Nutrition is likely one of the areas of our life that we can exert complete control over. As our world and its politics become more conflicted the comfort of the food we eat can take on more meaning and a sense of stability in our lives.

References

Medical News Today: Why is nutrition so hard to study?