Unlike carbohydrates, proteins, and nucleic acids, they are not polymers but small molecules, which vary considerably in polarity.
Lipids, along with carbohydrates, proteins, and nucleic acids, are among the four main classes of biologically essential organic molecules found in all living organisms.
Its quantity and quality in the diet can influence cell, tissue, and body physiology, including hydrophobic molecules, such as triglycerides or sterol esters, and others more soluble in water, such as phospholipids or very short-chain fatty acids, the latter utterly miscible with water and insoluble in non-polar solvents.
The little or no solubility in water of many of them means that they are subject to special procedures at all stages of their use, that is, in digestion, absorption, transport, storage, and service.
Lipids are wax-like fat molecules found in the human body and other organisms.
They play several different roles in the body, such as feeding it, storing energy for the future, sending signals throughout the body, and being a component of the cell membranes that hold cells together.
Types of lipids
Lipids can be classified into three main types:
Triglycerides are lipids obtained from dietary fat sources and are stored for future use.
Steroids are lipid types that include cholesterol and sex hormones like estrogen and testosterone and other hormones like adrenaline, cortisol, and progesterone.
Phospholipids are derived from triglycerides. These lipids are responsible for protecting and isolating cells.
Foods that provide lipids
Fats make up the largest category of lipids, and they also meet the terms triacylglycerols, triglycerides, and glycerolipids. There are several types of fats, such as:
It is a lipid that exists as a solid substance at room temperature. Milk, cheese, meat, and other foods of animal origin contain saturated fat.
Palm oil, cocoa butter, coconut oil, and other tropical oils also contain saturated fats, and these types of oils can be found in processed foods like snacks, whipped toppings, and coffee creamers.
Butter, margarine, and shortening also contain a large amount of saturated fat.
Unsaturated or unsaturated fat
It is a lipid that exists as a liquid when it is at room temperature. Plant oils contain unsaturated fat. There are two types of unsaturated fats:
- Monounsaturated fat is found in olive, peanut, canola, and other vegetable oils.
- Trans fat is a lipid that has undergone a process called hydrogenation. Hydrogenation makes the fat harder, which can then be used to make crunchy foods like chips and cookies and some types of salad dressings, margarine, and other processed foods.
It is also found in vegetable oils, such as sunflower, sesame, corn, soybeans, and safflower oil. Seafood also contains polyunsaturated fats. There are two types of polyunsaturated fats:
- Omega-6 fatty acids: Lipids found in soybean oil, safflower oil, sunflower oil, and other liquid vegetable oils.
- Omega-3 fatty acids: Lipids can be found in walnuts, flax seeds, soybean oil, canola oil, shellfish, salmon, herring, sardines, anchovies, and trout.
Fat-soluble vitamins are lipids:
- Vitamin A is essential for immune function, vision, and reproduction and is found in colorful fruits and vegetables and whole milk and liver.
- Vitamin D improves how the intestines absorb calcium, zinc, phosphate, iron, and magnesium. It is obtained from certain foods such as salmon, mackerel, beef liver, tuna, egg yolk, some cheeses, and from exposure to sunlight.
- Vitamin E protects the human heart and helps protect the body from free radicals, thus helping to keep our cells healthy. It is found in nuts, seeds, and vegetable oils.
- Vitamin K allows blood to clot and can help with bone strength in the elderly. It can be found in kale, spinach, turnips, collards, chard, mustard greens, parsley, romaine lettuce, green leaf lettuce, Brussels sprouts, broccoli, cauliflower, cabbage, fish, liver, meat, eggs, and cereals.