Defining Nutrition, Health, and Disease

Life depends on nourishment and the quality of life depends greatly on the foods you choose to eat. Any discussion of nutrition must begin with an understanding of nutrition, nutrients, and their overall relationship to health and well-being.

Defining Nutrition, Health, and Disease

The word nutrition first appeared in 1551 and comes from the Latin word nutrire, meaning “to nourish.” Today, we define nutrition as the sum of all processes involved in how organisms obtain nutrients, metabolize them, and use them to support all of life’s processes. Nutritional science is the investigation of how an organism is nourished, and incorporates the study of how nourishment affects personal health, population health, and planetary health. Nutritional science covers a wide spectrum of disciplines. As a result, nutritional scientists can specialize in particular aspects of nutrition such as biology, physiology, immunology, biochemistry, education, psychology, sustainability, and sociology.

Without adequate nutrition the human body does not function optimally, and severe nutritional inadequacy can lead to disease and even death. The typical American diet contains adequate calories, but is lacking in many ways, from not containing the proper amounts of essential nutrients, to being too speedily consumed, to being only meagerly satisfying.

Registered Dietitians (RD), also called Registered Dietitian Nutritionists (RDN), are nutrition professionals who integrate their knowledge of nutritional science into helping people achieve a healthy diet and develop good dietary habits. Through their knowledge and experiences, RDs/RDNs specialize in translating nutrition science into practical advice. Becoming an RD/RDN requires a college degree with an emphasis in chemistry, anatomy and physiology, and other sciences, the completion of a 1200-hour dietetic internship in clinical and community settings, and passing the national certification exam. Once you achieve RD/RDN status, you must complete 75-hours of continuing education in nutrition every five years. RDs/RDNs work in many diverse settings including hospitals, clinics, long-term care facilities, schools, health clubs, grocery stores, private practice, insurance companies, and corporate wellness programs. They can help you overcome disordered eating, set realistic weight loss and weight management goals, manage chronic diseases, or help you achieve optimal athletic performance. The Academy of Nutrition and Dietetics (AND) is the largest organization of nutrition professionals in the world and dietitians registered with AND are committed to helping Americans eat well and live healthier lives.

Nutrition and Health and Disease

Your ability to wake up, to think clearly, to communicate, to hope, to dream, to go to school, to gain knowledge, to go to work, to earn a living, and to do all of the things that you like to do are dependent upon one factor—your health. Good health means you are able to function normally and work hard to achieve your goals in life. In 1946, the World Health Organization (WHO) defined health as “a state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity.”^[1] This definition was adopted into the WHO constitution in 1948 and remains to this day. A triangle is often used to depict the equal influences of physical, mental, and social well-being on health.

Disease is defined as any abnormal condition affecting the health of organisms and typically characterized by specific signs and symptoms. Diseases are broadly categorized as resulting from pathogens (i.e., bacteria, viruses, fungi, and parasites), deficiencies, genetics, and/or physiological dysfunction. Diseases that primarily affect physical health are those that impair body structure (as is the case with osteoporosis), or functioning (as is the case with cardiovascular disease). Mental illnesses primarily affect mental and social well-being.

The foods we eat affect multiple aspects of our health. For example, a teen with type 2 diabetes (a disease often brought on by poor diet and lack of physical activity) is first diagnosed by physical signs and symptoms such as increased urination, excessive thirstiness, and unexplained weight loss. But research has also found that teens with uncontrolled type 2 diabetes often have impaired thinking and may not interact well with others in school, thereby affecting mental and social well-being. This is just one example of a physiological disease that can affect physical, mental, and social aspects of health.

In the early twentieth century, most nutrition-related diseases and conditions were related to inadequate calorie consumption or deficiency of nutrients. In the latter part of the twentieth century nutrition scientists, public health organizations, and the American public increasingly recognized that eating too much of certain foods is linked to chronic diseases. Table below shows the top ten causes of death in the US. As you can see, many of these causes are related to nutrition. We now know that diet-related conditions and diseases include but are not limited to cardiovascular (heart) diseases including hypertension (high blood pressure) and stroke, obesity, type 2 diabetes, several forms of cancer, and osteoporosis.

references

Chapter 1, section 1.1 from Consumer Nutrition by Megan Grimsley and Susan Kazen published in 2021 under a CC BY-NC-SA license.

Author Notes
Portions of this chapter were taken from OER Sources listed below:

Tharalson, J. (2019). Nutri300:Nutrition. https://med.libretexts.org/Courses/Sacremento_City_College/SSC%3A_Nutri_300_(Tharalson)

Titchenal, A., Calabrese, A., Gibby, C., Revilla, M.K.F., 7 Meinke, W. (2018). Human Nutrition. University of Hawai’i at Manoa Food Science and Human Nutrition Program Open Textbook. https://pressbooks.oer.hawaii.edu

Zimmerman, M., & Snow, B. (2012). An Introduction to Nutrition, v. 1.0. https://2012books.lardbucket.org/books/an-introduction-to-nutrition/