5.6: Diabetes and Hypoglycemia
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- 82937
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)What is diabetes?
Diabetes is one of the top three diseases in America. It affects millions of people and causes tens of thousands of deaths each year. Diabetes is a metabolic disease of insulin deficiency and glucose oversufficiency. Like other diseases, genetics, nutrition, environment, and lifestyle are all involved in determining a person’s risk for developing diabetes. One sure way to decrease your chances of getting diabetes is to maintain an optimal body weight by adhering to a diet balanced in carbohydrate, fat, and protein intake. There are three different types of diabetes: type 1 diabetes, type 2 diabetes, and gestational diabetes.
Diabetes
Video \(\PageIndex{1}\). Introduction to Diabetes.1 Source: https://www.youtube.com/watch?v=wmOW091P2ew
Type 1 Diabetes
Type 1 diabetes is a metabolic disease in which insulin-secreting cells in the pancreas are killed by an abnormal response of the immune system, causing a lack of insulin in the body. Its onset typically occurs before the age of thirty. The only way to prevent the deadly symptoms of this disease is to inject insulin under the skin. Before this treatment was discovered, people with Type 1 diabetes died rapidly after disease onset. Death was the result of extremely high blood-glucose levels affecting brain function and leading to coma and death. Up until 1921, patients with Type 1 diabetes, the majority of them children, spent their last days in a ward where they lapsed into a coma awaiting death. One of the most inspiring acts in medical history is that of the scientists who discovered, isolated, and purified insulin and then went on to find out that it relieved the symptoms of Type 1 diabetes, first in dogs and then in humans. Frederick Banting, Charles Best, and James Collip went into a hospital ward in Toronto, Canada, and injected comatose children with insulin. Before they completed their rounds, children were already awakening to the cheers of their families.
A person with Type 1 diabetes usually has a rapid onset of symptoms that include hunger, excessive thirst and urination, and rapid weight loss. Because the main function of glucose is to provide energy for the body, when insulin is no longer present, no message is sent to cells to take up glucose from the blood. Instead, cells use fat and proteins to make energy, resulting in weight loss. If Type 1 diabetes goes untreated, individuals with the disease will develop a life-threatening condition called ketoacidosis. This condition occurs when the body uses fats and not glucose to make energy, resulting in a build-up of ketone bodies in the blood. It is a severe form of ketosis with symptoms of vomiting, dehydration, rapid breathing, confusion, and eventually coma and death. Upon insulin injection, these severe symptoms are treated, and death is avoided.
Unfortunately, although insulin injection prevents death, it is not considered a cure. People who have this disease are affected by many symptoms (Figure \(\PageIndex{1}\)). They must adhere to a strict diet to prevent serious complications. Individuals diagnosed with Type 1 diabetes are advised to consume a diet low in the types of carbohydrates that rapidly spike glucose levels (high-glycemic index foods), count the carbohydrates they eat, consume healthy-carbohydrate foods, and eat small meals frequently. These guidelines are aimed at preventing large fluctuations in blood glucose. Frequent exercise also helps manage blood glucose levels. Type 1 diabetes accounts for between 5 and 10% of diabetes cases.
Diabetes Symptoms
Figure \(\PageIndex{1}\). Overview of the most significant possible symptoms of diabetes. ("Main symptoms of diabetes" by Mikael Häggström has been released into the Public Domain.)
Type 2 Diabetes
The other 90 to 95% of diabetes cases are type 2 diabetes. Type 2 diabetes is defined as a metabolic disease of insulin insufficiency, but it is also caused by muscle, liver, and fat cells no longer responding to the insulin in the body. In brief, cells in the body have become resistant to insulin and no longer receive the full physiological message of insulin to take up glucose from the blood. Thus, similar to patients with Type 1 diabetes, those with Type 2 diabetes also have high blood-glucose levels.
For individuals with Type 2 diabetes, the onset of symptoms is more gradual and less noticeable than for those with Type 1 diabetes. The symptoms are increased thirst (polydipsia), increased urination (polyuria), unexplained weight loss, and hunger (polyphagia). Diabetes can be diagnosed by blood tests that determine the amount of glucose in the blood (Figure \(\PageIndex{2}\)). The A1C test measures how much blood sugar is attached to hemoglobin, a protein in the blood that carries oxygen. High A1C results suggest high blood sugar levels for an extended period. Blood glucose levels can also be measured during fasting or after a drinking a sugary drink.
The first stage of Type 2 diabetes is characterized by high glucose and insulin levels. This is because the insulin-secreting cells in the pancreas attempt to compensate for insulin resistance by making more insulin. In the second stage of Type 2 diabetes, the insulin-secreting cells in the pancreas become exhausted and die. At this point, individuals with Type 2 diabetes also have to be treated with insulin injections. Healthcare providers aim to prevent the second stage from happening. As with Type 1 diabetes, chronically high-glucose levels cause big detriments to health over time, so another goal for patients with Type 2 diabetes is to properly manage their blood-glucose levels. The front-line approach for treating Type 2 diabetes includes eating a healthy diet and increasing physical activity.
The Centers for Disease Control Prevention (CDC) estimates that as of 2023, 37 million Americans have diabetes, which is over 10 percent of the population.2 In 2017, the cost of diabetes to the United States was estimated at $327 billion.3 The incidence of Type 2 diabetes has more than doubled in America in the past thirty years, and the rise is partly attributed to the increase in obesity in this country. Genetics, environment, nutrition, and lifestyle all play a role in determining a person’s risk for Type 2 diabetes. We have the power to change some of the determinants of disease but not others. The Diabetes Prevention Trial that studied lifestyle and drug interventions in more than three thousand participants who were at high risk for type 2 diabetes found that intensive lifestyle intervention reduced the chances of getting type 2 diabetes by 58%.4
Having more than one risk factor for Type 2 diabetes substantially increases a person’s chances of developing the disease. Metabolic syndrome refers to a medical condition in which people have three or more risk factors for Type 2 diabetes and cardiovascular disease (Figure \(\PageIndex{2}\)). According to the International Diabetes Federation (IDF) people are diagnosed with this syndrome if they have central (abdominal) obesity and any two of the following health parameters: triglycerides greater than 150 mg/dL; high-density lipoproteins (HDL) lower than 40 mg/dL; systolic blood pressure above 100 mmHg or diastolic above 85 mmHg; or fasting blood glucose levels greater than 100 mg/dL.5
About 1 in 3 adults in the United States have metabolic syndrome.6 Studies vary, but people with metabolic syndrome have between a 9 and 30 times greater chance of developing Type 2 diabetes than those who do not have the syndrome.5
Testing for Diabetes
Figure \(\PageIndex{2}\). Diabetes Symtoms and Diagnostics. Blood tests for glucose help diagnose diabetes. Source: "Depiction of a home test for diabetes, test results, and the 'big 3' symptoms of diabetes" by myUpchar is licensed under CC BY-SA 4.0.
Gestational Diabetes
During pregnancy, some women develop gestational diabetes. Gestational diabetes is characterized by high blood-glucose levels and insulin resistance. The exact cause is not known, but it does involve the effects of pregnancy hormones on how cells respond to insulin. Gestational diabetes can cause pregnancy complications, and it is common practice for healthcare practitioners to screen pregnant women for this metabolic disorder. The disorder normally ceases when the pregnancy is over, but women who have had gestational diabetes have a 10-fold risk of developing type 2 diabetes as they age.7 Gestational diabetes not only affects the health of a pregnant woman but also is associated with an increased risk of obesity and Type 2 diabetes in her child.2
Prediabetes
As the term infers, prediabetes is a metabolic condition in which people have moderately high glucose levels but do not meet the criteria for diagnosis of diabetes. Over 96 million Americans are prediabetic and at increased risk for type 2 diabetes and cardiovascular disease.2 Prediabetes is reversible, and lifestyle changes such as eating healthy and exercising can help. The Centers for Disease Control (CDC) leads the National Diabetes Prevention Program, which can help support lifestyle changes. According to the CDC, participation in this program could lower the risk of developing type 2 diabetes by almost 60%.8
Long-Term Health Consequences of Diabetes
The long-term health consequences of diabetes are severe. They result from chronically high glucose concentrations in the blood accompanied by other metabolic abnormalities such as high blood-lipid levels. People with diabetes are between 2 and 4 times more likely to die from cardiovascular disease. Diabetes is the number one cause of new cases of blindness, lower-limb amputations, and kidney failure. Many people with diabetes develop peripheral neuropathy, characterized by muscle weakness, loss of feeling, and pain in the lower extremities. More recently, there is scientific evidence to suggest people with diabetes are also at increased risk for Alzheimer’s disease.
Diabetes Treatment
Keeping blood glucose levels in the target range (70–130 mg/dL before a meal) requires careful monitoring of blood glucose levels with a blood glucose meter, strict adherence to a healthy diet, and increased physical activity. Individuals with type 1 diabetes begin insulin injections as soon as they are diagnosed. Individuals with type 2 may require oral medications and insulin injections to maintain blood glucose levels in the target range. The symptoms of high blood glucose, also called hyperglycemia, are difficult to recognize, diminish in the course of diabetes, and are mostly not apparent until levels become very high. The symptoms are increased thirst and frequent urination.
Having glucose levels that are too low, known as hypoglycemia, is also detrimental to health. Hypoglycemia is more common in type 1 diabetes and is most often caused by injecting too much insulin or injecting it at the wrong time. The symptoms of hypoglycemia are more acute and include shakiness, sweating, nausea, hunger, clamminess, fatigue, confusion, irritability, stupor, seizures, and coma. Hypoglycemia can be rapidly and simply treated by eating foods containing about ten to twenty grams of fast-releasing carbohydrates. If symptoms are severe, a person is either treated by emergency care providers with an intravenous solution of glucose or given an injection of glucagon, which mobilizes glucose from glycogen in the liver. Some people who are not diagnosed with diabetes may experience reactive hypoglycemia. This is a condition in which people are sensitive to the intake of sugars, refined starches, and high-GI foods. Individuals with reactive hypoglycemia have some symptoms of hypoglycemia. Symptoms are caused by a higher-than-normal increase in blood insulin levels. This rapidly decreases blood-glucose levels below what is required for proper brain function.
"Insulin syringe and pen" by BruceBlaus is licensed under CC BY 3.0.)
The major determinants of Type 2 diabetes that can be changed are overnutrition and a sedentary lifestyle. Therefore, reversing or improving these factors through lifestyle interventions markedly improves the overall health of individuals with type 2 diabetes and lower blood-glucose levels. In fact, it has been shown that when people are overweight, losing as little as nine pounds (four kilograms) decreases blood-glucose levels in individuals affected by Type 2 diabetes. The Diabetes Prevention Trial demonstrated that by adhering to a diet containing between 1,200 and 1,800 kilocalories per day with a dietary fat intake goal of less than 25% and increasing physical activity to at least 150 minutes per week, people at high risk for type 2 diabetes achieved a weight loss of 7% and significantly decreased their chances of developing Type 2 diabetes.4
An unfortunate problem is that most individuals diagnosed with diabetes do not adhere to lifestyle interventions long-term. This is partly because of individual disinclination but also because health insurance companies do not provide continued financial support for dietary guidance and because primary care physicians do not prescribe dietary guidance from a dietitian. This shifts the way diabetes is treated away from lifestyle intervention toward medications, as the goal remains to manage blood-glucose levels. Numerous oral medications are available on the market and are often prescribed to treat Type 2 diabetes in combination.
The American Diabetes Association (ADA) has a website that provides information and tips for helping individuals with diabetes answer the question, “What Can I Eat?” Regarding carbohydrates, the ADA recommends that individuals with diabetes keep track of the carbohydrates they eat and set a limit. These dietary practices will help keep blood glucose levels in the target range.
Visit the ADA meal-planning website to learn more on making nutritious meals that help keep blood sugar levels in balance.
Attributions
- Zimmerman, "An Introduction to Nutrition (Zimmerman)", CC BY-NC-SA 3.0. The original material was updated. New figures and references were added.
References
- Centers for Disease Control and Prevention. What is Diabetes. [Video]. YouTube. https://youtu.be/wmOW091P2ew?si=Bx9QLfEPuBmtmhZw. Published March 27, 2015. Accessed August 2, 2023.
- Diabetes Basics. Centers for Disease Control and Prevention. Updated May 15, 2024. Accessed August 4, 2023. https://www.cdc.gov/diabetes/about/? CDC_AAref_Val=https://www.cdc.gov/diabetes/basics/diabetes.html.
- Health and Economic Benefits of Diabetes Interventions. National Center for Chronic Disease Prevention and Health Promotion. Updated May 15, 2024. Accessed August 4, 2023. https://www.cdc.gov/nccdphp/priorities/diabetes-interventions.html?CDC_AAref_Val=https://www.cdc.gov/chronicdisease/programs-impact/pop/diabetes.htm.
- Knowler WC, Barrett-Connor E, Fowler SE, et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med. 2002;346:393-403. doi:10.1056/NEJMoa012512.
- Alberti G, Zimmet P, Shaw J, Grundy SM. The IDF consensus worldwide definition of the metabolic syndrome. International Diabetes Federation. Published 2006. Accessed August 13, 2023. https://idf.org/media/uploads/2023/05/attachments-30.pdf.
- What Is Metabolic Syndrome? National Heart, Lung, and Blood Institute. Updated May 18, 2022. Accessed August 6, 2023. https://www.nhlbi.nih.gov/health/metabolic-syndrome.
- Gestational Diabetes. American Diabetes Association. Accessed August 13, 2023. https://diabetes.org/diabetes/gestational-diabetes.
- Prediabetes—Your Chance to Prevent Type 2 Diabetes. Centers for Disease Control and Prevention. Updated May 15, 2024. Accessed August 13, 2023. https://www.cdc.gov/diabetes/prevention-type-2/prediabetes-prevent-type-2.html?CDC_AAref_Val=https://www.cdc.gov/diabetes/basics/prediabetes.html.