Triacylglycerides are a type of fat, also known as lipids, that circulate in your blood. They represent the main form of stored energy in the body and are kept in your fat cells. While necessary for health, elevated levels can be associated with certain health risks.
Understanding Triacylglycerides: Fats in Food and Your Body
A triacylglyceride molecule is made of a single glycerol molecule and three fatty acid chains. The glycerol acts as a backbone for the fatty acids, which can vary in length and structure. This variation determines the specific characteristics of the triacylglyceride. Naturally occurring fats and oils are complex mixtures of these molecules.
The nature of these fats is determined by the fatty acids. Saturated fatty acids have no double bonds in their chemical structure, are solid at room temperature, and are found in animal products. Unsaturated fatty acids, including monounsaturated and polyunsaturated fats, have at least one double bond, making them liquid at room temperature and prevalent in vegetable oils. Trans fats are a type of unsaturated fat with a specific chemical structure that is particularly unhealthy.
Your body gets triacylglycerides in two primary ways: directly from your diet and through its own production. Dietary sources include fats and oils in foods like butter and cooking oils. The body also produces them when the liver converts excess calories, particularly from sugar and high-carbohydrate foods, into fat.
Triacylglycerides and cholesterol are different types of lipids with distinct functions. Triacylglycerides store unused calories to provide the body with energy. Cholesterol, a waxy substance, is used to build cells and produce certain hormones.
How Your Body Uses and Manages Triacylglycerides
When you eat, your body uses the calories it needs for immediate energy and stores the rest in adipose tissue, or fat cells. Between meals or during periods of fasting, your body can release these stored fats to meet its energy demands. This process of breaking down stored fat for energy is called lipolysis.
During lipolysis, hormones signal fat cells to release triacylglycerides into the bloodstream. They are then transported to tissues like the muscles and heart for fuel. Beyond energy, stored fat also provides insulation to help maintain body temperature and acts as a protective cushion around vital organs.
Because fats are not water-soluble, they cannot travel freely in the blood. The body packages triacylglycerides, cholesterol, and proteins into particles called lipoproteins. Dietary fats absorbed after a meal are packaged by the intestines into large particles known as chylomicrons, which deliver them to various tissues.
For triacylglycerides produced by the liver, a different lipoprotein is used. The liver bundles these fats into particles called very-low-density lipoproteins (VLDL). VLDL particles circulate in the blood, delivering the liver-produced triacylglycerides to cells. As the VLDL particles release their fatty cargo, they eventually transform into other types of lipoproteins.
Decoding Triacylglyceride Levels and Health Impacts
Triacylglyceride levels are measured in a standard blood test called a lipid panel, with results reported in milligrams per deciliter (mg/dL). Normal fasting levels are below 150 mg/dL. Levels between 150 and 199 mg/dL are classified as borderline high.
Levels from 200 to 499 mg/dL are considered high, and 500 mg/dL or above is very high. The medical term for elevated triacylglycerides is hypertriglyceridemia. This condition often occurs alongside other health issues like obesity and type 2 diabetes.
High triacylglycerides are linked to an increased risk of cardiovascular disease. Elevated levels contribute to atherosclerosis, the hardening and narrowing of the arteries, which can restrict blood flow and lead to a heart attack or stroke. Very high levels also pose a risk for acute pancreatitis, a sudden inflammation of the pancreas.
Several factors contribute to high triacylglyceride levels. A diet high in sugar, refined carbohydrates, and unhealthy fats is a primary cause. Other factors include a sedentary lifestyle, excessive alcohol consumption, and being overweight. Certain medical conditions, like poorly controlled type 2 diabetes, kidney disease, and hypothyroidism, can also elevate levels.
Approaches to Maintaining Healthy Triacylglyceride Levels
Managing triacylglyceride levels begins with lifestyle modifications, mainly diet and exercise. A primary dietary strategy is to reduce the intake of sugar and refined carbohydrates. This includes limiting sugary drinks, desserts, and foods made with white flour in favor of high-fiber foods like whole grains, vegetables, and legumes.
Choosing healthier fats is also beneficial. This means replacing saturated and trans fats, found in red meat and many processed foods, with monounsaturated and polyunsaturated fats. Good sources of these healthier fats include avocados, nuts, seeds, and olive oil. Incorporating omega-3 fatty acids from fatty fish like salmon can also help.
Regular physical activity helps lower triacylglycerides by using stored fat for energy and improving metabolic health. Aim for at least 30 minutes of moderate-intensity exercise, such as brisk walking, swimming, or cycling, on most days of the week.
For individuals with very high levels or those unable to lower them through lifestyle changes alone, a doctor may prescribe medication. These are typically used in combination with continued efforts in diet and exercise. Common medications include:
- Fibrates
- Statins
- Niacin
- High-dose fish oil supplements