Chapter 1. Introduction to Nutrition
Research and the Scientific Method
Where do you get your nutrition information? The news, articles on social media or word of mouth? Knowing which sources are trustworthy and which are based on scientific fact can be confusing. The best resources are called peer-reviewed or scientific journals. They reside in special databases such as Google Scholar, Pubmed or Medline to name a few. These journals contain articles written by nutritional scientists and reviewed by their peers, who are experts in their respective fields. The articles are summaries of experiments run (original studies) using the scientific method or summaries of a series of studies on a similar topic (reviews).
Nutritional scientists discover the health effects of food and its nutrients by first making an observation. Once observations are made, they come up with a hypothesis, test their hypothesis, and then interpret the results. After this, they gather additional evidence from multiple sources and finally come up with a conclusion. This organized process of inquiry used in science is called the scientific method.
In 1811, French chemist Bernard Courtois was isolating saltpeter for producing gunpowder to be used by Napoleon’s army. To carry out this isolation, he burned some seaweed and in the process, observed an intense violet vapor that crystallized when he exposed it to a cold surface. He sent the violet crystals to an expert on gases, Joseph Gay-Lussac, who identified the crystal as a new element. It was named iodine, the Greek word for violet. The following scientific record is some of what took place in order to conclude that iodine is a nutrient.
Observation. Eating seaweed is a cure for goiter, a gross enlargement of the thyroid gland in the neck.
Hypothesis. In 1813, Swiss physician Jean-Francois Coindet hypothesized that the seaweed contained iodine, and that iodine could be used instead of seaweed to treat his patients[1].
Experimental test. Coindet administered iodine tincture orally to his patients with goiter.
Interpret results. Coindet’s iodine treatment was successful.
Hypothesis. French chemist Chatin proposed that the low iodine content in food and water in certain areas far away from the ocean was the primary cause of goiter, and renounced the theory that goiter was the result of poor hygiene.
Experimental test. In the late 1860s the program, “The stamping-out of goiter,” started with people in several villages in France being given iodine tablets.
Results. The program was effective and 80 percent of goitrous children were cured.
Hypothesis. In 1918, Swiss doctor Bayard proposed iodizing salt as a good way to treat areas endemic with goiter.
Experimental test. Iodized salt was transported by mules to a small village at the base of the Matterhorn where more than 75 percent of school children were goitrous. It was given to families to use for six months.
Results. The iodized salt was beneficial in treating goiter in this remote population.
Experimental test. Physician David Marine conducted the first experiment of treating goiter with iodized salt in America in Akron, Ohio.[2]
Results. This study was conducted on over four thousand school children, and found that iodized salt prevented goiter.
Conclusions. Seven other studies similar to Marine’s were conducted in Italy and Switzerland, which also demonstrated the effectiveness of iodized salt in treating goiter. In 1924, US public health officials initiated the program of iodizing salt and started eliminating the scourge of goiter. Today, more than 70% of American households use iodized salt and many other countries have followed the same public health strategy to reduce the health consequences of iodine deficiency.
Career Connection
What are some of the ways in which you think like a scientist, and use the scientific method in your everyday life? Any decision-making process uses some aspect of the scientific method. Think about some of the major decisions you have made in your life and the research you conducted that supported your decision. For example, what brand of computer do you own? Where is your money invested? What post-secondary institution do you attend?
Indigenous Ways of Knowing
Traditional ecological knowledge, otherwise known as Native science [3], refers to Indigenous knowledge of the land, its processes, and management needs. Despite the lack of recognition it receives, Native science is rooted in the same scientific method used in Western society. The first step in the Native scientific method is observation; Indigenous peoples have been closely examining the natural world to establish an understanding of its processes and systems.[4] Additionally, another key component of the Native scientific method involves experimentation, which relates to learning through trial and error. For example, Indigenous peoples would often examine the effects of eating certain berries to determine whether they were poisonous or safe to eat. However, prior to conducting these experiments, Indigenous peoples would perform background research to determine whether or not the edibility of that new berry or food had been previously studied. If so, they would try the new berry or food themselves to replicate past studies and compare the results.[5] These berry experiments clearly highlight the similarities between Native science and Western science. However, it is also important to note the differences between the two. Unlike Western science, Indigenous ways of knowing take a holistic approach to exploring the interrelationships between individuals and the land they reside on. This Indigenous worldview of interconnectedness is summarized by the phrase, “mitákuye oyás’iŋ,” which translates to “human beings are related to everything and everyone.” [6] From this, it can be understood that Indigenous peoples share a sacred and reciprocal relationship with the Earth and its natural processes. On the other hand, Western ways of knowing are rooted in objectivity and logic; nature is considered an object of study and other living beings are viewed as a means to human ends.[7] Western science focuses on observable phenomena and thus disregards the relationships and experiences individuals share with the world around them.[8] Therefore, Indigenous ways of knowing can be used to study the natural world using frameworks and concepts, such as interconnectedness, which are evidently missing in Western science.
Evidence-Based Approach to Nutrition
It took more than one hundred years from iodine’s discovery as an effective treatment for goiter until public health programs recognized it as such. Although a lengthy process, the scientific method is a productive way to define essential nutrients and determine their ability to promote health and prevent disease. The scientific method is part of the overall evidence-based approach to designing nutritional guidelines.[9] An evidence-based approach to nutrition includes: [10]
- Defining the problem or uncertainty (e.g., the incidence of goiter is lower in people who consume seaweed)
- Formulating it as a question (e.g., Does eating seaweed decrease the risk of goiter?)
- Setting criteria for quality evidence
- Evaluating the body of evidence
- Summarizing the body of evidence and making decisions
- Specifying the strength of the supporting evidence required to make decisions
- Disseminating the findings
The Food and Nutrition Board, under Health Canada, constructs its nutrient recommendations (i.e., Dietary Reference Intakes, or DRI) using an evidence-based approach to nutrition. The entire procedure for setting the DRI is documented and made available to the public.
- Zimmerman, M.B. Research on Iodine Deficiency and Goiter in the 19th and Early 20th Centuries. Journal of Nutrition. 2008; 138(11), 2060–63. http://jn.nutrition.org/content/138/11/2060.full Accessed September 17, 2017 ↵
- Carpenter, K.J. David Marine and the Problem of Goiter. Journal of Nutrition. 2005; 135(4), 675–80. http://jn.nutrition.org/content/135/4/675.full?sid=d06fdd35-566f -42a2-a3fd- efbe0736b7ba Accessed September 17, 2017. ↵
- We recognize that Native can be an outdated term to refer to Indigenous peoples, to be in keeping with the referenced article (Elk, L. (2016). Native Science: Understanding and Respecting Other Ways of Thinking. Rangelands, 38(1), 3–4.) we have chosen to keep the term Native in this portion of the text. However, please feel free to reach out if you feel we should change this ↵
- Elk, L. (2016). Native Science: Understanding and Respecting Other Ways of Thinking. Rangelands, 38(1), 3–4. ↵
- Elk, L. (2016). Native Science: Understanding and Respecting Other Ways of Thinking. Rangelands, 38(1), 3–4. ↵
- Elk, L. (2016). Native Science: Understanding and Respecting Other Ways of Thinking. Rangelands, 38(1), 3–4. ↵
- Stinson, J. (2018). Learning across knowledge systems 2: What are indigenous and western ways of knowing? CRIAW. ↵
- Stinson, J. (2018). Learning across knowledge systems 2: What are indigenous and western ways of knowing? CRIAW. ↵
- Myers E. Systems for Evaluating Nutrition Research for Nutrition Care Guidelines: Do They Apply to Population Dietary Guidelines? J Am Diet Assoc. 2003; 12(2), 34–41. http://jandonline.org/article/S0002-8223(03)01378-6/abstract. Accessed September 17, 2017. ↵
- Briss PA, Zara S, et al. Developing an Evidence-Based Guide to Community Preventive Services—Methods. Am J Prev Med. 2000; 18(1S), 35–43. https://www.ncbi.nlm.nih.gov/pubmed/10806978. Accessed September 17, 2017. ↵
