One of the most Prevalent Health

 Abstract

Type 2 diabetes is one of the most prevalent health complications in the United States, affecting over 20 million citizens and costing billions of dollars. As a result of this disease being one of the leading causes of death in the United States, it has forced millions of people to be hospitalized. Type 2 diabetes is common among people who are obese, have high fat diets, and fail to exercise. The disease occurs due to inefficient usage and production of insulin and beta cell dysfunction. Glucotoxicity and lipotoxicity are both contributing factors to impaired function of beta cells and beta cell turnover. When tested, saturated fats had detrimental effects on insulin sensitivity and beta cell function, whereas monounsaturated fats prompted beta cell proliferation and increased insulin sensitivity. In the test meals with saturated fats, the insulin sensitivity decreased and beta cell function decreased. Diets containing high amounts of saturated fatty acids significantly increases one's risk of developing type 2 diabetes.

Introduction

The study of the structural elements of fatty acids and their impact on the human body is one of the most enigmatic, yet critical research fields in nutrition. It is essential to have fat in one's diet in order to assist the body's ability to absorb fat soluble vitamins and go through vital processes such as membrane synthesis, protein and carbohydrate modification, construct structural elements in cells, and produce signaling compounds. Although fats play a critical role in one's health, certain fats can be detrimental to the body, leading to beta cell dysfunction, insulin resistance, obesity, and chronic diseases like type 2 diabetes. The development of type 2 diabetes is an extremely prominent health issue for citizens of the United States; it is a chronic issue in which the body is unable to use the available insulin it produces efficiently. Insulin is an essential hormone produced by pancreatic islets that help the body use digested food for its metabolic needs. Approximately 23.1 million people in the United States are diagnosed with diabetes, costing over 245 billion dollars annually [4].

Saturated Fats

What are saturated fats and where can they be found in our diets?
From a chemical standpoint, Saturated fats are fats that are solid at room temperature and do not contain double bonds between their carbon molecules. This is because they are saturated with hydrogen molecules. High concentrations of saturated fatty acids are primarily found in animal products, however, a few plant products also contain them. Suggesting that these fats can be detrimental to one's health, the biggest sources of these fats that cause a concern for citizen in the United States include but are not limited to, pizza, cheese, milk, butter, dairy desserts, meat products, cookies, and fast food dishes.

Monounsaturated Fats

What are monounsaturated fats and where can they be found in our diet?
In contrast to saturated fats, monounsaturated fats are liquid at room temperature and contain fat molecules that have one unsaturated carbon bond, also called a double bond. Consumption of these fats can be good for one's health as they lower LDL cholesterol, which is a waxy substance that can evoke blockage in arteries. As a result of keeping LDL cholesterol low, it immensely reduced one's risk of developing heart disease or stroke. Monounsaturated fats are typically associated with several health benefits and are considered good or beneficial fats; they have the ability to "improve blood cholesterol levels, ease inflammation, stabilize heart rhythms" [11]. High concentration of these fats can be found in plant based foods such as olive, peanut, and canola oils, avocados, nuts, and seeds.

Beta Cells

What are Beta cells and their importance to the body?
Beta cells are a type of cell that are found in pancreatic islets, and carry a vital role in the body. The main role of beta cells is to produce and secrete a hormone called insulin, which is responsible for the regulation of glucose in blood. Beta cells quickly respond to changes in blood glucose concentrations by secreting and producing insulin. When the glucose concentration outside of the cell is high, the glucose enters the cell through facilitated diffusion. After entering the beta cell through glucose transporters, the glucose is phosphorylated as shown in the figure below.

Glycolytic flux and tricaboxylic acid cycle activity both increase, resulting in an increase of ATP production in the mitochondria; as the ATP to ADP ratio increases due to metabolism of glucose, ATP sensitive potassium ion channels close, inhibiting the diffusion of potassium out of the cell. The accumulation of potassium ions causes the membrane to have a more positive charge, opening voltage gated channels, allowing calcium to enter the cell. As a result of the calcium ions entering the cell, vesicles that contain insulin fuse with the membrane, inducing secretion of insulin through exocytosis. It is critical for beta cells to function properly and release insulin so the body has access to the chemical when it is needed.

Type 2 diabetes is a condition in which the body acquires a greater blood glucose level than normal, also called hyperglycemia. People with type 2 diabetes fail to use their insulin properly. Insulin is a vital hormone that helps cells turn glucose from food into energy. in early stages, the pancreas produces higher amounts of insulin, however, over time it cannot keep up. As a result, it cannot make enough insulin to keep blood glucose at a normal level. People who are overweight and do not exercise regularly are at a significantly higher risk of developing diabetes.

Type 2 diabetes can inflict numerous health issues, which is why it is important to know its symptoms. Some symptoms of type 2 diabetes include increased thirst and hunger, dry mouth, frequent urination, unexplained weight loss or weight gain, headaches, decreased or blurred vision, fatigue, numbness, and in rare occasions, loss of consciousness. According to studies, 8.6% or 21 million adults were diagnosed with type 2 diabetes in 2016 in the United States [8]. Type 2 diabetes can be extremely dangerous to one's health and in some cases puts people in the hospital. 7.2 million hospital discharges were reported in 2014 for people with diabetes [1].

1.5 million of them suffered from cardiovascular diseases, 108,000 had to have lower extremity amputations, and 168,000 suffered from diabetic ketoacidosis. Diabetes is the "7th leading cause for death in the United States in 2015," after 252,806 death certificates declared diabetes as the underlying cause of death [1]. In addition to its alarming health consequences, type 2 diabetes is costly. The 2012 estimated cost of diabetes in the United States was 245 billion dollars, and the individual medical expenditures for people diagnosed with diabetes were about 13,700 dollars per year [1].

Saturated and Monounsaturated fats and their influence on beta-cell function
According to several researches, strong evidence proves that saturated fatty acids are frequently linked to apoptosis and reduced proliferation of beta cells, whereas monounsaturated fats may counteract this effect. Many of these studies associate saturated fats to insulin secretion dysfunction and the frequency of diabetes 2, however, it is unclear how much unsaturated fats influence the "postprandial control of insulin secretion and resistance, even in healthy subjects" [10]. In a study by The American Journal of Clinical Nutrition, the mean plasma glucose, insulin, triglyceride, and FFA concentrations were measured in an SFA meal, MUFA meal, HPSO meal, VEFO meal, and a control meal (shown in figure 1). While the glucose levels were similar for all of the meals, there was a significant difference of the AUC for insulin, triglycerides, and FFA between the control meal and the high-fat meals.

In addition to testing the plasma glucose, insulin, triglyceride, and FFA concentrations in separate meals, they gathered data on postprandial beta cell function and insulin sensitivity. The research showed that the subjects proportionally became more insulin resistant as the meals went from concentrations of monounsaturated fatty acids to saturated fatty acids (VEFO>ROO>HPSO>SFA).

As the table above confirms, monounsaturated fat meals were shown to make the subjects more insulin sensitive than the saturated fat meals. "When compared with MUFAs, [the] data showed that SFAs dramatically decreased postprandial insulin sensitivity toward blood FFAs, ie, they reduce postprandial ISI(FFA)GTTTM, which suggests that lower ratios of MUFAs to SFAs in dietary fats could profoundly affect the antilipolytic action of insulin" [10]. Thus, the ratio of monounsaturated fats to saturated fats suggest that postprandial metabolism of saturated fats may be linked to dysfunction of beta cells, which is a risk factor of type 2 diabetes.

Numerous studies demonstrate that saturated fats lead to beta cell dysfunction and insulin resistance, preceding the development of hyperglycemia and type 2 diabetes.
The development of type 2 diabetes typically occurs as a response of insufficient diets and lack of physical activity in people who have predispositions in beta cell dysfunction and insulin resistance. "In insulin-resistant states, pancreatic islets usually respond by increasing insulin secretion to maintain normoglycemia, a process termed ?? cell compensation" [9]. This process includes the expansion of beta cell mass, an increase of insulin biosynthesis, and enhancement of nutrient secretion "coupling processes with increased sensitivity to glucose, FFAs, and GLP-1 stimuli [9]. One of their studies proved that due to the altered metabolic signaling network and accumulation of toxic lipids, "inadequate beta cell compensation [resulted] in onset of mild hyperglycemia at 8-9 weeks of age in the ZDF rat," resulting in severe beta cell failure.

In their studies of glucolipotoxicity, saturated fats were cytotoxic, whereas monounsaturated fats were protective. Monounsaturated fats more effectively promote TG/FFA cycling; unlike saturated fats, monounsaturated fats do not cause the accumulation of ceramides or deplete mitochondrial cardiolipin levels, which are both processes that are linked to cytotoxicity [9].

The Process of Beta Cell Turnover

The first step in the process of beta cell turnover is a through the overproducing of insulin. When beta cells are exposed to an excess amount of glucose or saturated fatty acids for an extended period of time, the pancreas produces an excess amount of insulin. Consequently, this over producing induces the beta cells into a state of cellular stress, decreasing the degree of insulin sensitivity (Figure 3).

Next, the production of insulin can no longer continue to increase, therefore the insulin production is maximized. At this point in the process, the pancreatic beta cells are no longer able to produce insulin. After the immense stress of producing more insulin that physiologically normal for a beta cell over a long period of time, the stressed beta cells begin to die off, also known as beta cell turnover (Figure 4).

The Role of Beta Cell Turnover in Type 2 Diabetes

Ultimately compounded by low insulin sensitivity, beta cell dysfunction is a critical determinant for type 2 diabetes. People who suffer from type 2 diabetes become resistant to its insulin, and in response, their beta cells compensate by producing a larger amount of insulin. When this occurs over a long period of time, the beta cells wear out, also referred to as beta cell turnover.

Discussion
An immense amount of scientific research supports the fact that a high saturated fat diet is the most effective method of causing beta cell turnover and insulin resistance. As shown earlier, data clearly shows that saturated fatty acids have a negative effect on insulin sensitivity, whereas monounsaturated fats have a positive impact. Beta cells are extremely important for the human body because if insulin was not produced, glucose would accumulate in blood, causing inflammation in tissues, and could eventually lead to severe metabolic problems, organ failure and death. When beta cell are exposed to high saturated fat concentrations for a long period of time, their self defense mechanisms can no longer protect them from dysfunction. Beta cell insulin production depends on several factors. Some of these factors include fat and glucose concentrations, and the amount of time they are exposed to high levels of these concentrations. In these high concentrations, the pancreas produces an excess amount of insulin in attempt to combat the issue. Beta cell dysfunction and insulin resistance are both linked to hyperglycemia, which is characterized by type 2 diabetes.

Conclusion

In conclusion, diets containing saturated fatty acids have a negative impact on insulin secretion and resistance. Data showed that meals with saturated fatty acids compared to monounsaturated meals significantly decreased insulin sensitivity and increased insulin resistance. Beta cells are particularly sensitive to these diets. Beta cell failure occurs when islets are unable to sustain the compensation for insulin resistance from the high accumulation of glucose in blood.

The process of beta cell dysfunction and death is progressive; after hyperglycemia is established, the beta cells functionality begins to deteriorate and beta cell mass decreases due to apoptosis. In contrast, diets with monounsaturated fats had the opposite effect, stimulating beta cell proliferation. The ratio of monounsaturated fats to saturated fats in the data is useful while designing a diet to reduce postprandial insulin concentrations.

Excessive intake of these fatty acids can eventually lead to type 2 diabetes, the most common form of diabetes. When improperly managed, the disease can lead to numerous health problems including heart disease, blindness, nerve damage, kidney disease, amputations, and in severe cases, death. Small changes in one's lifestyle and diet can make an immense impact on their life, greatly reducing risk of getting type 2 diabetes and other chronic diseases. Therefore, it is critical to make necessary adjustments in one's lifestyle to prevent the development of this disease.

References

• [1] American Diabetes Association. Classification and diagnosis of diabetes. Diabetes Care. 2017;40(suppl 1):S11-S24.
• [2] Asif, M. (2014). The prevention and control the type-2 diabetes by changing lifestyle and dietary pattern. Journal of Education and Health Promotion, 3, 1. doi:https://dx.doi.org/10.4103/2277-9531.127541
• [3] Cerf, M. E. (2013, March 10). Beta Cell Dysfunction and Insulin Resistance. Retrieved from https://www.frontiersin.org/articles/10.3389/fendo.2013.00037/full
• [4] Current Burden of Diabetes in the U.S. (n.d.). Retrieved from https://www.niddk.nih.gov/health-information/communication-programs/ndep/health-professionals/practice-transformation-physicians-health-care-teams/why-transform/current-burden-diabetes-us
• [5] How Fat Kills Insulin-Producing Beta Cells. (2018, August 11). Retrieved from https://www.masteringdiabetes.org/how-fat-kills-beta-cells/
• [6] Maedler, K., Spinas, G., Dyntar, D., Moritz, W., Kaiser, N., & Donath, M. Y. (2001, January 01). Distinct Effects of Saturated and Monounsaturated Fatty Acids on ??-Cell Turnover and Function. Retrieved from https://diabetes.diabetesjournals.org/content/50/1/69.short
• [7] Maedler, K., Oberholzer, J., Bucher, P., Spinas, G. A., & Donath, M. Y. (2003, March 01). Monounsaturated Fatty Acids Prevent the Deleterious Effects of Palmitate and High Glucose on Human Pancreatic ??-Cell Turnover and Function. Retrieved from https://diabetes.diabetesjournals.org/content/52/3/726
• [8] Morr, M. (2018, May 31). Diabetes Prevalence by Type in the United States: CDC report. Retrieved from https://www.clinicaladvisor.com/diabetes-resource-center/cdc-report-diabetes-by-type-us-adults/article/760827/
• [9] Prentki, M., & Nolan, C. J. (2006, July 03). Islet ?? cell failure in type 2 diabetes. Retrieved from https://www.jci.org/articles/view/29103
• [10] Sergio, Beatriz, Pacheco, M, Y., Villar, Muriana, & JG, F. (2008, September 01). Distinctive postprandial modulation of ?? cell function and insulin sensitivity by dietary fats: Monounsaturated compared with saturated fatty acids. Retrieved from https://academic.oup.com/ajcn/article/88/3/638/4754442
• [11] Types of Fat. (2018, July 24). Retrieved from https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/types-of-fat/  

Cite this page