Lipids are a diverse group of biomolecules that include fats, oils, waxes, sterols, and various other compounds. They signify an essential role in the human body by providing a great source of energy, building cell membranes, being instrumental in hormone production, and transporting important vitamins. Lipids come in different types, called simple lipids, complex lipids, and derived lipids. Almost every food we intake contains lipids; let’s explore the three main types of lipids in detail.
Simple lipids, also known as neutral fats, are composed of just two types of components: glycerol and fatty acids. The glycerol molecule has three carbon atoms, and a fatty acid chain consist of long hydrocarbon chains. The combination of these two components, through dehydration synthesis, forms an ester bond, this is, a bond between a hydroxyl group and a carboxyl group. The three forms of simple lipids are:
Triglycerides are the most common type of lipid found in our foods and are also the storage form of energy in cells. Triglycerides are made of three fatty acids bound to a glycerol backbone. The fatty acids can be the same or different and can vary in length and degree of saturation. Saturated fatty acids have no carbon-carbon double bonds, whereas unsaturated fatty acids have one or more.
The different types of fatty acids determine the physical properties of triglycerides. For example, solid fats, such as animal fat, tend to be saturated fats. In contrast, vegetable oils tend to be unsaturated and liquid at room temperature. The variation in the saturation level determines the fat’s texture and stability in a process called hydrogenation, which involves converting unsaturated fats to trans fats, harmful to health.
Waxes are water-repellent and are used by living organisms as protective coatings. Waxes are esters that make use of long-chain fatty acids and long-chain alcohols. Their hard texture and protective nature make them suitable for covering insect carapaces or bird feathers.
Complex lipids are also called phospholipids as they have a phosphate head, which is hydrophilic, and two hydrophobic tails. They are one of the primary components of cell membranes and are oppositely orientated in bilayers. They are composed of three parts:
Glycerophospholipids are abundant in the human body and are important in biological membranes. It means they are one of the fundamental building blocks of cells. Glycerophospholipids contain a hydrophilic phosphate group, two hydrophobic fatty acid chains, and a polar head group. The head group varies and can contain other functional groups such as ethanolamine, serine, inositol, or choline, resulting in different types of phospholipids.
Sphingolipids are derived from the amino alcohol sphingosine and are key components of the cell membrane. They consist of a long-chain fatty acid, sphingosine, and a polar head. Sphingolipids are very important for cell-to-cell communication, controlling recognition, and specific processes such as apoptosis (programmed cell death).
Derived lipids or secondary lipids are lipids that have intrinsic properties of simple or complex lipids, but some enzymatic actions that occur in cells, lead to their formation. The properties of derived lipids are related to the type of lipid from which they were derived or how they were modified. The two types of derived lipids are:
Steroids are lipids characterized by a four-ringed structure, and we often think of them as hormones. The human body produces cholesterol, estrogen, testosterone, and cortisol, all of which are steroids. Cholesterol is essential for many functions, such as building membrane structure, so our liver produces the cholesterol we need. When we consume excess cholesterol, it accumulates in our blood vessels and increases the risk of heart disease or stroke. Other steroids produced by the body are related to reproduction, development or control of metabolism.
Eicosanoids are derived from fatty acids and regulate multiple physiological processes such as immune response, blood clotting, inflammation, and blood pressure. They are formed by oxidative processes that occur during cellular responses to injury or stress. Eicosanoids are often misunderstood or viewed negatively; however, they are vital and play a crucial role in maintaining optimal health.
The Importance of Lipids in Human Health
Lipids are integral components within the human body’s foundation, are essential to various functions, and their proportion and quality matter. They assure the correct sources of energy for bodily functions as a structural foundation for vital organs and hormones. Lipids accomplish vital biological functions by producing and regulating pathways to maintain homeostasis; thus, a proper balance within the body is crucial.
The Role of Lipids in Nutrition
There are specific needs for Good Fats in our daily diet, the deficiencies of which can impact the body’s overall functions. To promote cardiovascular and overall health, foods rich in omega-3 fatty acids such as chia seeds, flaxseeds, and walnuts should be consumed regularly. Oily fish, such as salmon and sardines, are an excellent source of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). This variety of lipids is essential in producing and maintaining healthy neural tissue, which supports healthy cognitive function.
Saturated Fatty Acids
The intake of saturated fatty acids should be limited because they raise harmful LDL (Low-Density Lipoproteins) cholesterol levels in the blood. This increases the risk of atherosclerosis, a condition where arteries become narrowed, leading to heart attacks and strokes.
Trans fats may appear in the food chain because of the hydrogenation of unsaturated fats artificially. Unlike other lipids, the typical role these fats cover in the human body is harmful to health. They can raise LDL cholesterol, lower HDL (High-Density Lipoproteins) cholesterol, and lead to the endothelial dysfunction of blood vessels.
Lipids are an essential part of the human body, performing vital roles such as energy storage, transport, and hormone production. Classified as simple, complex, or derived, each has unique properties that determine their role in the body. A balanced diet that contains a healthy mixture of Omega 3 and omega 6 fatty acids is crucial to maintain optimal health. Saturated fatty acids and artificial trans fats should be limited.
FAQs Related to “Which Are the Three Main Types of Lipids?”
- What are lipids? – Lipids are a diverse group of biomolecules that include fats, oils, waxes, sterols, and various other compounds. They play an essential role in the human body by providing a great source of energy, building cell membranes, being instrumental in hormone production, and transporting important vitamins.
- Which are the three main types of lipids? – The three main types of lipids are simple lipids, complex lipids, and derived lipids.
- What are simple lipids? – Simple lipids, also known as neutral fats, are composed of just two types of components: glycerol and fatty acids. The three forms of simple lipids are triglycerides, waxes, and steroids.
- What is the significance of complex lipids? – Complex lipids are also called phospholipids as they have a phosphate head, which is hydrophilic, and two hydrophobic tails. They are one of the primary components of cell membranes and are oppositely orientated in bilayers.
- What are the primary derived lipids? – Derived lipids or secondary lipids are lipids that have intrinsic properties of simple or complex lipids, but some enzymatic actions that occur in cells lead to their formation. The two types of derived lipids are steroids and eicosanoids.
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- Brouwer, I. A. (2013). The Importance of Omega-3 Fatty Acids in Cardiovascular, Metabolic, and Pulmonary Health. Advances in Nutrition, 4, 3-4, 524-527.