Metabolic syndrome is an aggregate of risk factors that raise the risk of heart disease, diabetes, and stroke. Metabolic health is defined as the biochemical process involved in the body to maintain homeostasis, or normal function (National Heart, Lung, and Blood Institute, n.d.). According to the American Heart Association (AHA, 2016), metabolic syndrome is a severe health condition that affects approximately 23% of adults in the United States.
A bundle of health conditions characterizes the metabolic syndrome. These conditions include hypertension (high blood pressure), obesity, abnormal lipid levels, and hyperglycemia (high blood glucose). Metabolic syndrome is diagnosed with a person meets three or more of the following criteria:
- Android (abdominal) obesity: waist circumference greater than 40" in men, and greater than 35" in women);
- Triglyceride level 150 mg/dL or greater, or currently prescribed drug treatment for elevated triglycerides;
- High-density lipoprotein (HDL) level less than 40 mg/dL in men or less than 50 mg/dL in women;
- Systolic blood pressure 130 mm Hg or greater, or diastolic blood pressure 85 mm Hg or greater;
- Fasting glucose of 100 mg/dL or greater or currently prescribed drug therapy for elevated glucose (AHA, 2016; Lewis, 2017).
Metabolic syndrome is becoming a common concern in the United States. Risk factors that increase the likelihood of acquiring metabolic syndrome are overweight or obesity, insulin resistance, Caucasian race, and male gender. Conversely, a healthy diet, exercise, and weight loss are protective factors against the development of metabolic syndrome (AHA, 2016).
Insulin resistance is the primary underlying cause of developing metabolic syndrome (Lewis, 2017). Insulin resistance is when the body cannot utilize insulin efficiently. The muscles and liver cells in the body do not respond sufficiently to normal levels of insulin. Gaining weight by increased food intake and lack of physical activity are common ways people develop insulin resistance that can result in metabolic syndrome (AHA, 2016).
Certain people are genetically prone to develop insulin resistance, while others develop insulin resistance due to excess visceral adipose tissue. Visceral adipose tissue is the fat stored within the abdominal cavity. Excess visceral fat, leading to android obesity, is strongly associated with metabolic syndrome. Visceral adipose tissue is concerning because it lies between organs in the abdominal cavity (AHA, 2016).
Excess adipose tissue in the lower body, gynoid obesity, is different than android obesity because it is generally subcutaneous fat. Android obesity is influenced by several factors that include hormones (specifically in post-menopausal women) and genetics. Research suggests that adipose cells in the abdominal cavity are biologically active. These cells are alive and producing hormones and cytokines that can significantly affect health and lead to devastating disease processes. Cytokines such as tumor necrosis factor and interleukin-6 are immune system chemicals that can increase the likelihood of an individual developing cardiovascular disease. Also, these cytokines and other biochemicals linked to visceral adipose tissue may negatively affect coagulation, blood pressure, and insulin sensitivity (Harvard Health Publishing, 2019).
Visceral adipose tissue also causes harm because of its location: in the abdomen, near the portal vein. The portal vein transports blood from the intestines to the liver. Nearby visceral adipose tissue releases free fatty acids that can be absorbed by the portal vein. This absorption can influence the production of blood lipids (fats). This cycle directly links visceral fat with increased cholesterol and insulin resistance (Harvard Health Publishing, 2019).
“Patients with metabolic syndrome are reported to have a two-fold increase in risk for heart attack and stroke as well as a five-fold increase for developing diabetes mellitus compared to patients without metabolic syndrome. This dramatically increased risk emphasizes the clinical importance of identifying metabolic syndrome as a true syndrome, as well as diagnosing patients with it earlier on to minimize the risks and begin preventive treatment” (Guentert, Valdez, & Yang, 2014, p. 6).
Treatment and Prevention of Metabolic Syndrome
One of the best ways to prevent and treat metabolic syndrome is by diet control. Changing dietary habits can help reduce weight, lower blood pressure, balance cholesterol levels, and stabilize blood glucose levels. Dietary changes are one of the first action plans implemented by healthcare providers to treat metabolic syndrome (Lewis, 2017).
Losing 7-10% of body weight can substantially reduce insulin resistance, blood pressure, and risk for developing diabetes. The Dietary Approaches to Stop Hypertension (DASH) diet is an example of a guideline that encourages eating vegetables, fruits, lean protein, and high-fiber whole grains. The DASH diet also encourages limiting sugar, fats, and salt intake (Mayo Clinic, 2019). The Mediterranean diet has also been proven to reduce the risk of metabolic syndrome. This diet is mostly plant-based, with moderate fat and protein intake. It encourages regular intake of fruits, vegetables, nuts, cereal, whole grains, monounsaturated fats such as olive oil, and lean protein from fish and poultry. It discourages sugar, red meat, saturated fat, and dairy intake (D’Innocenzo, Biagi, & Lanari, 2019).
Foods high in sugar, including simple, refined carbohydrates, have been proven to increase the risk for type 2 diabetes and cardiovascular disease. Both conditions are associated with metabolic syndrome. Chemical names in food and drinks often hide sugar. The nurse should educate the patient to look for sugar in ingredient lists by the chemical names: sucrose, glucose, dextrose, fructose, maltose, and/or levulose. The nurse should include education regarding refined and processed carbohydrates. Patients should avoid or significantly reduce their intake of corn syrup, white bread, white flour, white rice, baked sweets, candy, soda, and juice (Iftikhar & Olsen, 2018).
Artificial trans fats (or trans fatty acids) are created through an industrial process. The purpose of these fats is to add hydrogen to liquid oils to make them more solid (AHA, 2019). Foods such as packaged cookies, pies, frozen pizza, cake mixes, potato chips, and deep-fried foods are high in trans fats or “partially hydrogenated oils” (Iftikhar & Olsen, 2018). “In November 2013, the U.S. Food and Drug Administration (FDA) made a preliminary determination that partially hydrogenated oils are no longer Generally Recognized as Safe (GRAS) in human food” (AHA, 2016).
Trans fats are very inexpensive and easy to produce. They are also long-lasting and give food a desirable taste and texture. However, trans fats raise low-density lipoprotein (LDL), or “bad” cholesterol levels and lower HDL, or “good” cholesterol levels. There is also an increased risk for developing type 2 diabetes with the ingestion of trans fats. “Several countries (e.g., Denmark, Switzerland, and Canada) and jurisdictions (California, New York City, Baltimore, and Montgomery County, MD) have reduced or restricted the use of trans fats in food service establishments” (AHA, 2019). Conversely, omega 3 fatty acids are beneficial in helping raise HDL levels. Omega 3 fatty acids are found in fish, most seeds and nuts, avocados, and navy beans; they are great options to promote vascular health (Iftikhar & Olsen, 2018).
Increased sodium in the diet is also linked to poor health outcomes. Research has shown strong links between high dietary sodium and hypertension. Common foods that are high in sodium are potato chips, salted nuts, smoked meats, frozen dinners, salad dressings, condiments, boxed cereal, canned soup, pudding, cake mixes, and canned vegetables (Iftikhar & Olsen, 2018). According to the AHA (2018), sodium intake should be limited to 2,300 mg per day, with 1,500 mg per day being ideal. Reducing sodium intake by 1,000 mg per day can lower blood pressure and promote heart health. Most people only require approximately 500mg of sodium per day to function properly. However, if someone lives a lifestyle where large amounts of sodium are lost in sweat, larger quantities of supplemental sodium may be required (AHA, 2016).
Sugar, carbohydrates, trans fats, and sodium are examples of substances in food that can be harmful to health. However, some foods can improve metabolic syndrome. Fiber-rich foods such as fruits, vegetables, oats, barley, lentils, whole-grain bread, quinoa, and bran can help lower risks for cardiovascular disease. A daily diet inclusive of additional fiber can reduce LDL and blood glucose levels. It is recommended that women consume at least 25g of fiber per day and men 38g of fiber per day (Iftikhar & Olsen, 2018).
Foods high in potassium also help control blood pressure. Potassium is an electrolyte that can work to counter the effects of sodium, which in turn decreases blood pressure. Foods high in potassium are bananas, oranges, grapefruit, dates, collard greens, lentils, oat bran, yogurt, edamame beans, mushrooms, and potatoes with skins (Iftikhar & Olsen, 2018).
Recently, research in metabolic health has focused on leptin, a “fullness hormone” produced by adipose cells to signal the hypothalamus that there is sufficient energy stored for use. This satiety signal then serves to suppress appetite and expend energy as needed. Chronically high levels of circulating leptin, as seen in overweight patients are believed to lead to reduced sensitivity to this signal, or leptin resistance, which causes increased appetite. Extreme dieting to lose weight can also lead to the unintended consequence of chronically increased levels of leptin; having a contradictory effect on appetite and metabolic rate. Instead, studies indicate that patients should be instructed to adjust quantities based on hunger and fullness cues to help regulate these satiety hormones (Outland, 2018).
A decline in physical activity in otherwise healthy young adults is associated with unfortunate metabolic consequences such as increased visceral fat and decreased insulin sensitivity. Research has proven a positive correlation between consistent physical activity and the prevention of metabolic syndrome. Exercise is now recognized as a medical treatment (Paley & Johnson, 2018). Regular exercise has proven effective in decreasing triglyceride levels and increasing HDL cholesterol in patients diagnosed with metabolic syndrome (Lewis, 2017).
Weight reduction through exercise is essential to prevent metabolic syndrome. With exercise, muscle mass is maintained or increased, and more fat is reduced than with dietary changes alone. Maintaining lean body mass through regular exercise promotes glucose transport and fat metabolism while limiting the release of cytokines in visceral fat. Education of exercise benefits is essential for patients because a challenge for health care professionals is a lack of motivation in patients to utilize exercise as a treatment for metabolic syndrome (Paley & Johnson, 2018).
According to the Mayo Clinic (2019), experts recommend at least 30 minutes of moderate exercises, such as brisk walking, every day. Exercise can be in 30-minute increments or split up throughout the day. Patients should be encouraged to supplement healthy activity instead of sedentary options. For example, take the stairs instead of the elevator. Another option could be wearing a pedometer and setting a step goal. When available, walk instead of drive or park further away from an entrance (Mayo Clinic, 2019). If using a wearable, 5,000- 10,000 steps daily should be an introductory goal. Research indicates that high-intensity interval training (HIIT) done for 18-25 minutes two or three times a week leads to improved glucose tolerance, leptin levels, and heart rate. Patients should be encouraged to exercise with a friend for accountability, select an activity that they enjoy doing, and establish realistic goals (Outland, 2018).
There is no specific pharmacologic management for metabolic syndrome. However, drug therapy may be implemented for particular indications. Cholesterol-lowering and antihypertensive drugs are often used. Metformin (Glucophage) is also useful in preventing and treating insulin resistance. Metformin (Glucophage) acts by lowering glucose levels and increasing cells’ sensitivity to insulin (Lewis, 2017).
Complications related to metabolic syndrome can include atherosclerosis (hardening of the arteries), type 2 diabetes, myocardial infarction (heart attack), kidney disease, stroke, fatty liver, and cardiovascular and peripheral artery disease (AHA, 2016). Nurses should be skilled in assessing symptoms and laboratory markers that may indicate a complication from metabolic syndrome in those patients at risk.
Nursing Interventions for Patients with Metabolic Syndrome
The predominant roles of the nurse when caring for a patient with metabolic syndrome are education and prevention of complications. The goal is for patients to lose 7-10% of their body weight. Patients should be educated to choose foods that are low in fat and high in fiber; encourage intake of whole grains, fruits, and vegetables. Education should also be provided to increase physical activity. Smoking and excess alcohol use can increase the risk of cardiovascular disease and insulin resistance. Smoking and alcohol cessation resources should be offered to patients who abuse alcohol or use tobacco products. Patients should understand that these lifestyle changes are intended to accomplish weight loss and a decrease in cholesterol, serum glucose, and blood pressure (AHA, 2016).
Future research continues to look at whether metabolic syndrome is a “real” syndrome or only a collection of signs and symptoms of other disease processes combined. Some organizations argue that the syndrome is too loosely defined while others, such as the American College of Cardiology, state it is a useful theory (Guentert et al., 2014).
Future research is also geared toward developing genetic screening for metabolic syndrome. This screening would allow for the identification of patients who have a predisposition for the disease. With this knowledge, patients could begin preventative factors earlier to avoid adverse health outcomes such as type 2 diabetes mellitus and cardiovascular disease (Guentert et al., 2014).
Leptin research continues to evolve, as well as other appetite and satiety hormones such as ghrelin. Sleep disturbance causes elevated levels of both of these hormones, indicating that consistent, uninterrupted sleep may also prove to be an efficacious aspect of non-pharmacological treatment for metabolic disorders. A diet rich in diverse, whole foods is consistently favored over-processed, convenience foods, but research has found that this may have something to do with the gut microbiome. Prebiotics and probiotics supplements, along with a wholesome diet, may lead to a more robust gut flora, which may help with appetite suppression, leptin sensitivity, insulin sensitivity, and resting metabolic rate (Outland, 2018).
American Heart Association (2016). About metabolic syndrome. Retrieved from https://www.heart.org/en/health-topics/metabolic-syndrome
D’Innocenzo, S., Biagi, C., & Lanari, M. (2019). Obesity and the Mediterranean diet: A review of evidence of the role and sustainability of the Mediterranean diet. Nutrients, 11(6), 1306. doi: 10.3390/nu11061306
Guentert, D., Valdez, A., & Yang, S. (2014). Is it clinically useful to identify metabolic syndrome as a real syndrome? Retrieved from https://www.acc.org/latest-in-cardiology/articles/2014/08/25/15/46/is-it-clinically-useful-to-identify-metabolic-syndrome-as-a-real-syndrome
Harvard Health Publishing (2019). Abdominal fat and what to do about it. Retrieved from https://www.health.harvard.edu/staying-healthy/abdominal-fat-and-what-to-do-about-it
Iftikhar, N., & Olsen, N. (2018). Metabolic syndrome diet. Retrieved from https://www.healthline.com/health/metabolic-syndrome-diet.
Lewis, S. L. (2017). Obesity. In Medical surgical nursing assessment and management of clinical problems (10th ed., pp. 874-892). St. Louis, MO: Elsevier.
Mayo Clinic (2019). Metabolic syndrome. Retrieved from https://www.mayoclinic.org/diseases-conditions/metabolic-syndrome/diagnosis-treatment/drc-20351921
National Heart, Lung, and Blood Institute. (n.d.). Metabolic syndrome. Retrieved October 2019 from https://www.nhlbi.nih.gov/health-topics/metabolic-syndrome
Outland, L. (2018) Evidence-based ways to promote metabolic health. The Journal for Nurse Practitioners, 14(6), 456-62. doi: 10.1016/j.nurpra.2018.02.010
Paley, C., & Johnson, M. (2018). Abdominal obesity and metabolic syndrome: Exercise as medicine? BMC Sports Science, Medicine and Rehabilitation, 10(1). doi: 10.1186/s13102-018-0097-1