Anatomy-Lexicon

Adipose tissue

definition

Adipose tissue is a type of connective tissue in the human body that takes on a variety of vital functions.

Adipose tissue consists of individual fat cells, which appear under the microscope as comparatively large, empty (because they were formerly fat-filled) rounded cells. The fat cells are through loose connective tissue stored together in groups, some of which have a lobular structure.

The proportion of adipose tissue in the body depends on a number of factors, but mainly on the ratio of physical activity to energy intake.

Read more on this topic: Fats in the human body

Functions of adipose tissue

There are different types of adipose tissue, and with them different functions:

1. The storage or depot fat. As the name suggests, this fatty tissue mainly serves as an energy store if the body cannot rely on energy supply in the form of food for a long time. A person can survive from this storage fat for up to 40 days, depending on their constitution. Nowadays, this fact is more of a burden than a benefit for many people, because the stored fat is mainly found on the abdomen and hips.

The proportion of storage fat varies between 10-15% in athletes, 15-25% in people of normal weight, and up to over 50% in obese, i.e. obese patients. Bodybuilders can achieve body fat percentages of less than 6% in phases of competition, but a minimum of 3-5% (men) or 10-13% (women) is considered essential for survival.

2. the insulating fat: adipose tissue is an excellent heat store. It is not for nothing that seals or polar bears, which have to survive in cold areas, have a large layer of fat to keep themselves warm. This is because adipose tissue conducts heat far worse than any other body tissue such as muscle tissue.

65% of the fatty tissue is in the subcutaneous tissue (Subcutis) of humans, the remainder is in the abdomen.

3. Adipose tissue is very soft and flexible, so it serves as a buffer and protection against external mechanical influences. Joints and internal organs in particular require a special cushion as they are very sensitive and at the same time very important for the body.

For example, there is a large fat apron in the abdomen at the level of the ribs, the so-called omentum majus (large abdominal network). It covers the anterior abdominal organs such as the small intestine and parts of the stomach.

There is also fatty tissue above the kidneys, cheeks, or in the eye socket. However, this is only converted into energy in extreme emergencies, i.e. in extreme states of hunger. In the case of very emaciated people, the eyes therefore always look sunken, as the fat pads behind them have been mobilized and the eyes "fall back".

4. The metabolic function: With 9.4 calories per gram, fat is the most energy-rich tissue in the body. Free fatty acids can be mobilized from the fat cells and released into the blood.There they have a half-life of only 1-2 minutes - that is, they are metabolized very quickly.

Muscles and organs prefer the free fatty acids over the sugar molecules that are also floating in the blood.

The fatty acid synthesis (Lipogenesis) is stimulated by the hormone insulin, fatty acid breakdown (Lipolysis) by the hormone glucagon.

A high blood sugar level, for example after eating, causes insulin to be released, stimulates fatty acid synthesis, and thus the storage of blood sugar in the form of fatty acids in adipose tissue. It is not for nothing that insulin is often referred to as the "fattening hormone".

Long-chain sugars, such as those contained in rice or whole grain products, usually have to be chopped up before they can be absorbed into the fatty tissue - the body in turn needs energy for this. That makes them healthier than containing short-chain carbohydrates like in white bread and beer.

Medical issues

Too high a body fat percentage is medically unfavorable.

Excessive adipose tissue can be a nuisance for both cosmetic and medical reasons.

On the one hand, high levels of body fat are often associated with psychological distress.

Please also read: Obesity and psychology

On the other hand, adipose tissue is very heavy (around 940 grams per liter) and therefore places great mechanical stress on bones and joints. Blood vessels and organs also suffer from too much fatty tissue and their function can be impaired. A well-known example of this is vein calcification or arteriosclerosis.

Around life-threatening consequences how Thrombosis or Cardiovascular diseases to prevent The attending physician tries first and foremost for one natural weight loss in the form of more physical activity and healthier / more conscious diet.

Read about this too: Diet for overweight

The basic idea is to reduce the storage fat that the body's energy reserves hold by creating an energy deficit. Simply put, if the body consumes more energywhen he picks up he picks up back to the storage fat - You pick up.

If this form of therapy is not successful due to a lack of cooperation on the part of the patient or other circumstances, one can contact invasive measures such as a Stomach reduction surgery To fall back on. A band is placed around part of the stomach and this is artificially made smaller. The body can subsequently eat less food, build less energy reserves, and as a result less adipose tissue invest. By increased physical activity can do that within half a year to a whole year Adipose tissue significantly reduced become.

Other, non-invasive measures also aim to make the stomach smaller, for example by taking up a type of sponge that expands in the stomach and reduces its volume.

In general it can be stated that a Avoid short-chain carbohydrates (Such as white bread, sweets and soft drinks) as well as on very high-fat diet (Pork neck, salami) always leads to a reduction in fatty tissue.

In the opposite case, at stronger Malnutrition,is a high calorie diet indexed. This can go through special nutritional preparations take place, which usually have an energy content of over 2 calories per gram. The goal here is that too Protection, insulation and energy storage function of adipose tissue restore.

A widespread misconception is by the way, you can through targeted training of individual parts of the body, such as stomach or bottom alone in these places Break down fat tissue.

Of the Breakdown of adipose tissue takes place centrally, the fat distribution pattern (i.e. the places where you prefer to put fat) are gender-specific and individually different. You can roughly say that men preferably in the abdominal area Put on fatty tissue, women rather in the hip area. One speaks of one in men apple-shaped, in women of one pear-shaped distribution pattern.

A reduction in the fatty tissue there is only possible through one general lifestyle change and not possible through locally concentrated training alone. After all, the body's cells are in one constant renovation process, which is why the fatty tissue is always redistributed according to the genetically predetermined distribution pattern.

Of course, isolated training of a single part of the body also burns energy and reduces fat tissue - just not necessarily exactly on the trained body region.

Adipose tissue and metabolism

Adipose tissue is necessary for the body to survive, too much Body fat percentage harmful, however.

From 30% fat tissue in the body one speaks of Obesity (Obesity).

Many aim in Germany Preventive measures aimed to warn consumers about unhealthy diets. An example are those prescribed on food Energy value tables, which indicate the percentage of the product, which it from daily needs covers. Guideline values are 2500 for men and 2000 for women Calories per day. Depending on the sporting activity, these values can of course vary up or down. Professional racing cyclists or extreme mountaineers, for example, consume up to 10,000 calories a day to cover their energy needs.

However, people with a normal metabolism should always make sure to stay in the 2000-2500 calorie range, and with if necessary sporting activity balance. For example, squash and spinning are sports that burn a lot of energy. So a large amount of adipose tissue is consumed here.

On the other hand, a Diet change promote weight loss on Mediterranean food. The rule of thumb is: guide the body more energy too when he needs the will excess energy stored in adipose tissue.

Comorbidities and risks of being overweight

In order to prevent comorbidities associated with being overweight, a change in diet is essential.

Concomitant diseases that are associated with an increase in the proportion of fatty tissue in the body shortness of breath, decreased performance, Tiredness, high blood pressure, Listlessness, but also psychological symptoms like depression, or social retreat.

With strong, unwanted weight gain but should always be one Hypothyroidism to be clarified.

This leads due to insufficient production of the Hormones Thyroxine and Triiodothyronine to a reduced energy expenditure in the body and thus to one increased build-up of adipose tissue, speaks weight gain. An underactive thyroid can be checked by your family doctor by taking a blood sample and then taking it Blood test determine in the laboratory.

Also Type 2 diabetes (so-called Adult diabetes) and arteriosclerosis are among the risks of being overweight.

In either case is one Diet and lifestyle change advised to reduce the excess fat going on.

Brown adipose tissue

From the so-called "white adipose tissue" is this "brown adipose tissue"to delimit.

While the former is the usual "normal" fat, the latter is one special form of adipose tissue there that one in activated form especially in newborns finds, and there primarily in the neck and chest area.

Its function is Heat productionwhich is particularly important in newborns as it is amplified by Hypothermia are affected.

The brown adipose tissue gets its brown color from a particularly high number Mitochondria - the so-called "power plants of the cell". These produce the required heat.

Until a few years ago it was assumed that adults no longer had brown adipose tissue because it was simply no longer needed. However, recent research showed that also in adult humans over 10% brown adipose tissue is present - albeit in an inactivated form. This plays a role insofar as an artificial activation of this fat tissue causes an increased energy consumption and could help patients lose weight.

Rodents can, for example, actively convert white into brown adipose tissue and use this to produce heat during hibernation. An actual feasibility is still the subject of research as of 2015.