Fat; body fat
Adipose tissue is commonly known as body fat. It is found all over the body. It can be found under the skin (subcutaneous fat), packed around internal organs (visceral fat), between muscles, within bone marrow, and in breast tissue. Men are more prone to storing visceral fat (fat around their internal organs), leading to ‘central obesity’ around the middle of their abdomen. However, women tend to store more subcutaneous fat within the buttocks and thighs. These differences are due to the sex hormones produced by males and females.
Adipose tissue is now known to be a very important and active endocrine organ. It is well established that adipocytes (or fat cells) play a vital role in the storage and release of energy throughout the human body. In addition to adipocytes, adipose tissue contains several other cells that can produce hormones in response to signals from the rest of the organs in the body. Through the actions of these hormones, adipose tissue plays an important role in the regulation of glucose, cholesterol, and the metabolism of sex hormones.
A number of different hormones are released from adipose tissue and these are responsible for different functions within the body. Examples of these are:
Both too much and too little adipose tissue can have severe health implications. More commonly, too much adipose tissue leads to obesity. Obesity can lead to several health problems, especially if there is too much visceral fat. Obesity increases the risk of developing type 2 diabetes as it causes the body to become resistant to the normal glucose-lowering effect of insulin. This resistance to the action of insulin results in high levels of blood sugar, which is harmful for health. Obesity also increases the chance of developing high blood pressure, high cholesterol levels, and an increased tendency for blood to clot. These factors increase the risk of heart attacks, stroke, and abnormal blood clotting in the legs or lungs (venous thrombo-embolism).
Abnormal storage of adipose tissue (lipodystrophy) can also cause similar problems. This can be seen due to rare inherited conditions (inherited lipodystrophy) and can also be due to use of medications for the treatment of HIV (acquired lipodystrophy).
In eating disorders (such as anorexia nervosa), the patient does not eat enough food to maintain their adipose tissues levels. This can also cause low levels of important reproductive hormones such as oestrogen resulting in thinning of bones (osteoporosis), and stopping of menstrual periods (amenorrhea).
Last reviewed: Nov 2021