Will donating blood make you fat? Can donating blood on an empty stomach help you lose weight? The doctor tells you the truth

In daily life, slogans such as "Free blood donation is everyone's responsibility" and "Regular blood donation saves lives" can be seen everywhere. As we all know, free blood donation can help people in need and even save other people's lives. However, many people are both familiar with and unfamiliar with free blood donation, and know very little about the real knowledge of blood donation. There have always been rumors about blood donation on the Internet: some people think that blood donation will make people fat, some people think that fasting blood donation can achieve the purpose of weight loss, and some people think that blood donation will harm health. So, is this really the case? In response to the above questions, China Digital Science and Technology Museum interviewed Ma Feng, deputy director of the Institute of Blood Transfusion, Chinese Academy of Medical Sciences.

The high school students' free blood donation coming-of-age ceremony held in Taiyuan, Shanxi (Photo source: Wei Liang/China News Network)

Obesity is not caused by blood donation, but is related to body metabolism.

Ma Feng said that there is no scientific basis for the claim that blood donation will make people fat. Blood donation will cause the body to lose blood volume in a short period of time. Our country's blood donation law stipulates that the blood volume of each person's blood donation is between 200 and 400 ml, which accounts for about 10% of the body's blood volume. This loss of blood volume is generally harmless to the human body. When donating blood, medical staff will select some healthy people for blood collection. Each blood collection station will give blood donors a certain amount of nutritional compensation after the blood collection is completed. The body's weight gain is mainly related to body metabolism, overeating, etc., and has no substantial relationship with the reduction of blood volume.

Donating blood on an empty stomach to lose weight is not reliable, as blood volume can be replenished in a few hours

Regarding the claim that donating blood on an empty stomach will help lose weight, Ma Feng said that this claim is also unreliable. The blood volume lost in blood donation is very small, and the lost blood volume can be replenished in a few hours. This has no necessary connection with fat metabolism, energy metabolism, and weight loss. The reason why blood collection stations require blood donors to donate blood on an empty stomach is that the blood is relatively "clean" when the stomach is empty. If you overeat, the fat particles in the blood and the toxins metabolized by the kidneys and liver will affect the blood quality.

Donating blood is not harmful to the body, but beneficial to the body

Some people believe that blood donation will harm health. Professor Li Bijuan, director of the blood transfusion department of Xiangya Hospital of Central South University, said in an interview with Changsha Evening News that proper blood donation will not affect health. The total blood volume of a normal person is about 4000-5000 ml (about 8% of body weight), and 20% is usually stored in organs such as the liver and spleen. After blood donation, this part of the stored blood will be quickly released into the peripheral blood and participate in the body's blood circulation. Moreover, human cells are constantly metabolizing. For example, the lifespan of red blood cells is 120 days, and that of platelets is 8-10 days. Blood donation can promote blood metabolism and reduce the occurrence of cardiovascular diseases.

In addition, Li Bijuan also said that a person's blood volume will be restored within 72 hours after donating blood, and the number of platelets in a healthy person is sufficient. Within 24 to 48 hours after donation, the number of platelets can be restored to the level before donation. Therefore, the interval between platelet donations is 2 weeks. There are nearly 150,000 healthy blood donors in Changsha every year, and they have proved with their own experience that blood donation does not harm health.

Since blood donation is harmless to the body, what should people pay attention to after donating blood? Ma Feng mentioned that our country's relevant blood donation law has very detailed regulations, such as blood donation must be done at designated blood stations. Local blood stations have corresponding supporting measures, such as providing rest areas and distributing milk, eggs, biscuits and other energy supplements to blood donors. After a few hours of rest, the blood volume in the body will return to normal. (Jing Chenlong)

Interviewed expert: Ma Feng, deputy director of the Institute of Blood Transfusion, Chinese Academy of Medical Sciences