Lipids / Fats - Fatty Acids for Health
In technical terms, fats and oils are called lipids (from the Greek lípos "fat"). Lipids are part of the group of macronutrients. A characteristic of fats is that they are insoluble in water in their normal state. Food fats are part of our diet. Fats are solid at room temperature, while oils are mostly liquid (depending on their saturation level). They are mainly used for cooking and as flavor carriers. Our body needs them mainly as a source of energy, for the absorption of vitamins, as a component of cell membranes, and for the development of the nervous system.
What plant fats consist of
Plant-based food fats consist of approximately 90% triglycerides. These are composed of a glycerin molecule to which three fatty acid molecules are attached. The remaining 10 percent consists of phospholipids, phytosterols, and fat-soluble vitamins. Cholesterol is not present in plant-based foods.
Plant-based foods not only differ in their fat content, but also in their fatty acid profiles. Fatty acids are organic acids that consist of carbon, oxygen, and hydrogen. More precisely, fatty acids are carboxylic acids (COOH) with a chain of carbon atoms to which hydrogen atoms are bound, with a methyl group (CH3) at the end of the chain. The end of the chain is also referred to as the omega end (ω-end). This is how, for example, omega-3 and omega-6 fatty acids get their names.
Due to their chemical structure, fatty acids can be classified according to their length (number of carbon atoms) and degree of saturation (number of double bonds).
Classification of fatty acids according to degree of saturation
If the carbon-hydrogen chain is fully "saturated" with hydrogen atoms, it is a saturated fatty acid. If there is at least one double bond between the carbon atoms, it is referred to as unsaturated fatty acids. The carbon-hydrogen chain is not fully saturated with hydrogen atoms.
|Degree of Saturation
|Saturated Fatty Acids
(Foods High in Saturated Fatty Acids)
|no double bonds between the carbon atoms
|Monounsaturated Fatty Acids
(Foods High in Monounsaturated Fatty Acids)
|one double bond between the carbon atoms
|Polyunsaturated Fatty Acids
(Foods High in Polyunsaturated Fatty Acids)
|multiple double bonds between the carbon atoms
Classification according to number of carbon atoms (length)
Fatty acids can be categorized differently based on the number of carbon atoms:
|Length of Molecule Chains
|Number of Carbon Atoms
|short-chain fatty acids
|up to 5
|medium-chain fatty acids
|6 to 12
|long-chain fatty acids
|13 to 20
|very long-chain fatty acids
|more than 22
Short-chain fatty acids can be better broken down and digested in the digestive tract than long-chain fatty acids.
Examples of Fatty Acids Based on Chemical Structure
To summarize the previous two sections, here are a few examples of fatty acids for better understanding:
- Lauric acid (12:0): 12 carbon atoms in the molecule chain, no double bond
- Oleic acid (18:1ω9): 18 carbon atoms in the molecule chain, one double bond (Omega-9 fatty acid)
- Linoleic acid (18:2ω6): 18 carbon atoms in the molecule chain, two double bonds (Omega-6 fatty acid)
- Alpha-linolenic acid (18:3ω3): 18 carbon atoms in the molecule chain, three double bonds (Omega-3 fatty acid)
Fatty Acids in Plant-Based Foods
Below is a selection of fatty acids that are present in plant-based foods:
|Saturated Fatty Acids
|Carbon Atoms: Double Bonds
|Monounsaturated Fatty Acids
|Carbon Atoms: Double Bonds
|Myristoleic acid (Omega-5)
|Palmitoleic acid (Omega-7)
|Oleic acid (Omega-9)
|Gadoleic acid (Omega-9)
|Nervonic acid (Omega-9)
Two fatty acids are essential (essential fatty acids) and cannot be produced by the body - linoleic acid and alpha-linolenic acid. Therefore, they must be obtained through the diet.
|Polyunsaturated fatty acids
|Carbon atoms : Double bonds
|Linoleic acid (Omega-6)
(Foods containing linoleic acid)
|Alpha-Linolenic acid (Omega-3)
(Foods containing alpha-linolenic acid)
|Gamma-linolenic acid (Omega-6)
|Eicosapentaenoic acid (Omega-3)
|Docosahexaenoic acid (Omega-3)
Functions of fats in the body
Triglycerides are the starting materials for the formation of sterols such as cholesterol, which in turn are responsible for the formation of hormones such as testosterone, progesterone, and estrogen, as well as vitamin D (which also belongs to the hormones). In the body, fatty acids are involved in many processes of building up, breaking down, and remodeling in the organism. They play an important role in building cell walls (membranes). In addition, fats are also involved in signal transmission between cells 1.
In addition, the skin is always covered with a layer of fat from within to reduce water loss through the skin and to inhibit the penetration of pathogens.
Fats facilitate vitamin absorption
For our bodies to absorb and utilize fat-soluble vitamins A, D, E, and K from food, fats are necessary 2. They also play an important role in the absorption of secondary plant compounds such as carotenoids. Scientists have found that fats also improve the absorption of carotenoids (found in carrots, tomatoes, among others) from foods 3 4. These compounds have a positive effect on the cardiovascular system and reduce the risk of cancer. Monounsaturated fatty acids had the highest absorption rate. For these reasons, fruits and vegetables should always be consumed with some fat. For example, soy yogurt or coconut oil are suitable as vitamin-soluble components for fruits, while olive oil is suitable for vegetable salads.
Fats as an energy source
The energy content of fats, at 9.3 kcal/g, is more than twice as high as that of carbohydrates and proteins (4.1 kcal/g each) 5. Therefore, dietary fats are the best natural energy carriers. It has been scientifically proven that 20% of the brain's energy needs are met by mitochondrial oxidation of fatty acids 6.
Nevertheless, carbohydrates, which are more quickly metabolized, are first used to ensure the body's energy supply. Only during intense physical activity, such as endurance exercises, are fats used for additional energy supply. In this process, glucose (simple sugar) is synthesized from glycerol. Glucose serves as energy for cells.
Due to their high energy density, fats also contribute to keeping blood sugar levels constant. Additionally, the feeling of satiety lasts longer.
Excess energy from fats, carbohydrates, and proteins is stored as fat tissue in the form of triglycerides when glycogen stores are full. This provides the body with energy for a longer period (e.g., during training) and serves as an additional energy source between meals.
An overall balanced plant-based diet rarely leads to excess fat. This can prevent numerous diseases and their consequences caused by high blood lipid levels and obesity (including atherosclerosis, diabetes, gout, high blood pressure). Hyperlipidemia and hypercholesterolemia are therefore almost unknown in vegans. Nevertheless, they should also rely on healthy and fresh foods and avoid processed products containing hydrogenated fats (trans fats are produced during fat hardening).
Showcasing research results from Spain, that a high-fat diet doesn't necessarily lead to weight gain 7. Nearly 7,500 mostly obese and overweight individuals between the ages of 55 and 80 supplemented their diet with extra-virgin olive oil or nuts. After nearly 5 years, the olive oil group had a decrease in body weight of 0.43 kg, while the nut group decreased by 0.08 kg. Waist circumference decreased by 55 cm in the olive oil group and 94 cm in the nut group.
Additionally, there are indications that a high-fat diet increases the risk of breast cancer 8.
Plant-based fats do not contain cholesterol
Vegans also don't have to worry about a low-cholesterol diet because plants and fungi are cholesterol-free. Instead, they contain phytosterols (also called phytosterols). Larger amounts of these are found in nuts, seeds, and kernels. Phytosterols have been shown to have a cholesterol-lowering effect 9.
Fats in the vegan diet
Compared to mixed diets and vegetarian diets, a vegan diet contains lower amounts of saturated fatty acids and higher amounts of healthier unsaturated fatty acids 10. Fats are mainly found in nuts and seeds (see fatty foods). Larger amounts can also be found in legumes and grains. Vegetables and fruits are generally low in fat except for avocados and olives. Olive oil is perfect for salads. We've summarized how much fat per day should be included in your diet here.
However, a vegan diet is usually rich in omega-6 and low in omega-3 fatty acids. It is particularly important for vegans to consume more omega-3s, as an imbalance between the two essential fatty acids, omega-6 and omega-3, can lead to health problems 11.