Lipids, what exactly are they?
Lipids play many roles, depending on their nature, since we distinguish storage lipids, structural lipids and functional lipids. Storage lipids are located in the adipose tissues and are mainly stored in the form of triglycerides. They make up the body's main energy reserve. Adipose tissue has a role as a thermal insulator, that is to say it takes part in maintaining our body temperature.
Did you know?
Triglycerides are fatty acids synthesised by the liver and the intestine, but they can also be supplied by the diet. A high blood concentration of triglycerides is considered a cardiovascular risk factor.
Structural lipids make up the cell membrane and maintain its integrity to ensure intracellular exchanges. Functional lipids can be the carriers of the fat-soluble vitamins (A, D, E and K) which enable their absorption and their transport within the body. As well as taking part in the prevention of many conditions (cardiovascular disease, inflammatory diseases and cancers), they play an important role in the manufacture of molecules essential to the body such as hormones. The metabolism of dietary lipids begins during their digestion and their intestinal absorption. The lipid nutrients will be cut into smaller molecules by an enzyme that will release the fatty acids, later captured by the liver. The majority of circulating fatty acids are captured by the body fat and stored in the form of triglycerides in the adipose tissue. The latter make up an important energy reserve that is easily usable.
What are the different fatty acids and in which foods can they be found?
Eating fats is therefore crucial for the body; however, some dietary sources are better than others.
Saturated fatty acids.
Saturated fatty acids are naturally manufactured by the liver, the brain and the adipose tissue, but they are also supplied by the diet. Saturated fatty acids are found in large quantities in butter, cream, cured meats, whole-milk dairy products, cheese, meat, but also in palm, coconut and palm-kernel oils. Saturated fatty acids can be classified into 3 categories according to their length: short, medium or long chains. Short- and medium-chain fatty acids will have a preventive role in the appearance of colon cancer. They are non-hypercholesterolaemic, that is to say they do not raise the cholesterol level and are not associated with the risks of cardiovascular disease. They are present in butter and cheeses. Long-chain saturated fatty acids are the major components of the myelin sheath (the envelope covering the neurons) in the cerebral nervous system. In excess, long-chain saturated fatty acids can present atherogenic effects (contributing to the formation of lipid plaques on the arteries) and thrombogenic effects (contributing to the formation of clots) and are hypocholesterolaemic, that is to say they play a role in lowering the level of blood cholesterol.
Unsaturated fatty acids.
There are two types of unsaturated fatty acids: monounsaturated and polyunsaturated.
Monounsaturated fatty acids.
Monounsaturated fatty acids, better known as omega-9 (oleic acid), are synthesised by the body and are also part of the make-up of triglycerides. They play a preventive role in the appearance of cardiovascular disease. They are found mainly in olive oil, avocado and oilseeds (almonds, walnuts, etc.) but can also be present in certain products of animal origin such as duck fat.
Polyunsaturated fatty acids.
Polyunsaturated fatty acids are so-called essential fatty acids, because our body cannot synthesise them and so they must necessarily be supplied by the diet. There are 2 types
1. Omega-3
Omega-3s are fatty acids that are hypotriglyceridaemic (lowering the level of triglycerides), anti-inflammatory, raise HDL cholesterol (good cholesterol) while improving vision and taking part in the prevention of neurodegenerative diseases. There are 3 of them:
- alpha-linolenic acid (ALA): it is found in linseed, rapeseed oils and in walnuts. This acid is the precursor of EPA and DHA. On the basis of an average energy need of 2,000 kcal, it is advisable to eat 2.2 g of alpha-linolenic acid.
- eicosapentaenoic acid (EPA): this acid is an anti-inflammatory that takes part in protecting the arteries and the heart. It also limits bone demineralisation. The recommended nutritional intake for this acid is 250 mg/day.
- docosahexaenoic acid (DHA): it is the main fatty acid present in the membranes of the neurons. It plays a fundamental role in the development of the brain and of vision. Just like EPA, DHA plays a role in protecting the heart. The recommended nutritional intake for this acid is 250 mg/day.
Linseeds and hemp seeds, walnuts and the oils derived from them are particularly rich in omega-3, as are oily fish. Omega-3s have a recognised protective effect on the cardiovascular system. DHA and EPA are mainly present in oily fish such as herring, mackerel or sardines.
2. Omega-6.
-Omega-6, or linoleic acid, is hypotriglyceridaemic, takes part in maintaining the integrity of your epidermis, in our immune defences and promotes an optimal reproductive function. In excess, they can be inflammatory and increase the risk of cardiovascular disease, diabetes and obesity. Omega-6, which is found in maize, soya and sunflower oils, is also considered a "good fat" but in excess, it prevents the optimal use of omega-3. In today's diet, we observe an excessive average intake of omega-6. However, the balance of the omega-6/omega-3 ratio is an important element for the proper functioning of our body. In this context, the omega-6/omega-3 ratio should be between 4 and 10, the ideal being 5. If the recommended daily intake of omega-3 is 2.7 g per day and the ratio should ideally be equal to 5, then it is advisable for you to eat about 13.5 g of omega-6 per day. At O.K.R, we use good-quality lipid sources such as rapeseed and sunflower oils, almonds, yellow linseeds, etc.
It is therefore important not to demonise the foods you eat because they all have a role to play in your dietary balance and in your health. Foods considered "fatty" at first glance are not necessarily bad for you.
How much lipid do you need?
ANSES recommends a daily lipid intake representing 35 to 40% of the total energy intake (TEI). These recommendations place strong emphasis on the quality of the lipids and not the quantity. Here are the recommended daily nutritional intakes for each type of fatty acid, based on an average energy need of 2,000 kcal.
- Saturated fatty acids: <8% of the TEI, i.e. 22 g
- Monounsaturated fatty acids: 20% of the TEI, i.e. 44 g
- Polyunsaturated fatty acids including:
-> omega-6: 10% of the TEI, i.e. 22 g -> omega-3: 2% of the TEI, i.e. 4.4 g including: ->ALA: 1% of the TEI, i.e. 2.2 g ->DHA and EPA: 0.12% of the TEI, i.e. 250 mg each.
Which fatty acids should be limited as much as possible?
It is recommended to eat a minimum of trans fatty acids in your diet. They increase the content of LDL cholesterol (bad cholesterol) and speed up the process of cholesterol formation in the arteries. In other words, these are fatty acids harmful to your health that you are advised to avoid as much as possible. Trans fatty acids are obtained by cooking oils at too high a temperature, during the manufacture of refined oils or during a hydrogenation process used in the food industry to solidify the fats used. Today, food brands are required to indicate the presence and the quantity of trans fatty acids in the product.
Did you know?
In O.K.R products, you will not find any processed fatty acids.
When should you eat lipids during the day?
"Don't eat fats in the evening, you are going to store them much more quickly!" This statement is very often repeated wrongly because it does not reflect the truth at all. What counts is the overall lipid intake over your day. Just like proteins and carbohydrates, it is important to spread your lipid consumption across all your meals: breakfast, lunch and dinner according to your needs.
Can you lose weight faster by removing lipids from your diet?
Logically yes, removing lipids from your diet lets you lose weight more quickly. Indeed, 1 g of lipid provides 9 kcal whereas carbohydrates and proteins only provide you with 4 kcal per gram. However, when you eat lipids again, your body will store these new reserves. You therefore greatly increase your chances of regaining the weight you have lost. It is important to understand that lipids, just like carbohydrates and proteins, do not make you fat if they are eaten according to your needs. They are, moreover, absolutely essential to your body.
