Dietary fats: essential and dangerous at the same time
There is always a heated debate about the pros and cons of fat. When consumed in the right amounts, fats provide energy, are a component of all body cells and protect us from the cold. However, we are consuming more and more fats and energy than we actually need through the diverse and increasingly fatty foods on offer. Metabolic diseases, overweight, calcification (sclerosis) as well as constriction of the blood vessels and circulatory disorders are the consequences. A moderate use of fats and the right sources of fat contribute significantly to maintaining health. Because not all fats are the same, as you will learn in the following article.
5 facts-to-go in a nutshell for you (at the bottom)!
Where does fat come from?
Fats are found in almost every food — in both animal and plant products. Along with carbohydrates and proteins, they are among the basic nutrients. Through our food we absorb individual free fatty acids, triglycerides and cholesterol from fats and oils. Triglycerides are the main component of oils and fats and are formed on the one hand from glycerol — a three-armed carrier, and on the other hand from saturated or unsaturated fatty acids bound to it.
Through the production of digestive enzymes and bile juices in the gastrointestinal tract, the ingested triglycerides are broken down step by step; free fatty acids and cholesterol can be absorbed directly and about 98% of them are absorbed from the intestine by healthy people. From the intestine, the fats are first transported through the lymphatic system and then through the blood. With the help of certain transport forms (lipoproteins), the fats are then further distributed in the body.
The individual fatty acids are differentiated according to chain length and the degree of saturation. Fats and oils only differ in the combination and sequence of their fatty acids — apart from fat-accompanying substances such as vitamins, sterols, etc. The different composition of the fatty acids on the body is the result of the different fatty acid chains. The different composition of the fatty acids at the glycerol determines the “goodness” and the solidity of a fat source. The more unsaturated the fatty acids, the healthier and more fluid (oily), the more saturated the more unhealthy and solid a fat source.
Now you are probably asking yourself: Coconut oil is solid, yet it is supposed to be healthy? In fact, coconut oil is 95% saturated fat, a staggering 45% more saturated fat than lard. However, the saturated fatty acids in coconut oil are not those that only raise the “bad” LDL cholesterol, but also increase the vasoprotective “good” HDL cholesterol. The bottom line is that the vascular-damaging effect of LDL is buffered by HDL. The lauric acid of coconut fat has the strongest HDL-increasing effect. Moreover, dietary fats are carriers of the fat-soluble vitamins A, D, E and K and thus enable the absorption of these vitamins.
Not all fats are the same
Apart from the amount of fat, the composition of the fatty acids in a fat source plays an important role. The absorption and metabolisation of dietary fats as well as their effects on lipid metabolism are primarily determined by the fatty acid pattern. Thus, omega-6 fatty acids such as arachidonic acid are metabolised to more pro-inflammatory tissue hormones, while omega-3 fatty acids such as eicosapentaenoic acid (EPA) are metabolised to more anti-inflammatory ones. Of course, it also plays a role for the health effects whether the diet is balanced and sufficient or over-caloric and unbalanced, whether enough antioxidant vitamins are supplied and which accompanying substances (e.g. polyphenols, secondary plant substances) a dietary fat contains.
What is the purpose of fat in the first place?
Our fatty tissue, which is distributed throughout the body, is not only an energy storage, shaper and insulator. Research in recent decades has discovered more and more functions that have led to the classification of different types of fat tissue (white, beige, brown fat tissue). While brown fat cells burn free fatty acids for heat production, white fat cells store them exclusively. Thus, an average person could go an estimated one month without food during periods of hunger. Depending on the body constitution, fat tissue makes up 10% (athletes) to 50% (people with obesity) of the body weight. It can therefore amount to up to 100 kg.
In order to survive, the organism needs a minimum storage of 0.5 to 1.0 kg of fat. Fat tissue is also hormonally active and secretes leptin and so-called adipokines. Large masses of adipose tissue seem to trigger inflammation, because with increasing fat mass, immune and inflammatory cells such as macrophages and monocytes infiltrate the adipose tissue. These secrete a number of inflammatory factors that increase the risk of various metabolic diseases and coronary heart disease.
Fat alone does not make you fat
Let us be clear: certain fatty acids are of great importance for a healthy fat metabolism. A blanket classification into cholesterol-lowering “healthy” vegetable oils (and margarines made from them) and cholesterol-increasing “unhealthy” butter is not sufficient; the composition of different fatty acids, accompanying oils and the diet in general determine the effects of fat consumption. If, for example, the diet is low in carbohydrates, the LDL cholesterol drops even if the proportion of saturated fatty acids is high. Fat metabolism disorders in particular — the number one risk factor for arteriosclerosis and cardiovascular disease — can ironically be prevented with the right fatty acids. Find out whether vegetable or animal sources of fat are better for this in our next article!
5 things you should take with you:
1. A moderate use of fats as well as the right fat sources contribute significantly to maintaining good health.
2. Fats are contained in almost every food — in animal as well as in vegetable products.
3. Fats and oils differ only in the combination and sequence of their fatty acids — apart from fat-accompanying substances such as vitamins, sterols, etc..
4. The different composition of the fatty acids at the glycerol determines the “quality” and the firmness of a fat source. The more unsaturated the fatty acids, the healthier and more fluid (oily), the more saturated the more unhealthy and solid a fat source.
5. Coconut fat contains 95% saturated fatty acids, 45% more than lard. However, coconut oil contains the most HDL-increasing lauric acid and thus has a vasoprotective effect despite being high in saturated fat.
Text sources:
(1) ernaehrung.de/foods
(2) Mensink, R.P. et al.: Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: a meta-analysis of 60 controlled trials. American Journal of Clinical Nutrition (2003) 77, 1146–1155.
(3) Miles, E A, Calder, P C. Influence of marine n-3 polyunsaturated fatty acids on immune function and a systematic review of their effects on clinical outcomes in rheumatoid arthritis. British Journal of Nutrition (2012) 107, 171–184.
(4) Forsythe, C E et al. Limited effect of dietary saturated fat on plasma saturated fat in the context of a low carbohydrate diet. Lipids (2010) 45, 947–962.
(5) Krauss, R M et al. Separate effects of reduced carbohydrate intake and weight loss on atherogenic dyslipidemia. American Journal of Clinical Nutrition (2006) 83, 1025–1031.
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