Why do we die if all body cells are renewed in 7 - 10 Years ?

Most of us read it in a number of life science articles that our body cells are renewed in every few years. Most of the articles claim that this duration ranges from 7 to 10 years. It means that every cell in our body is renewed in that duration. But if it is so then we should neither get old nor die. There must be something missing in the cell renewal theory as we get old and die in spite of getting cells renewed. Here betterhealthfacts.com will try to figure out the missing facts in this cell renewal theory. Read this article to know why we get old and die even after renewal of cells.

Different cell types have different life span

Life span of cells of different body organs is different. So different organs renew themselves in different time span. This time span for renewal of cells ranges from day to years. Therefore some researchers calculated the total time for renewal of whole body as 7 to 10 years. As per our research on internet it is just a false belief. There are some important parts of body, where the cells are not renewed. Average lifespan of cells of different organs can be used to calculate the total time in which that organ will be completely renewed. Here is some average data collected to show renewal time of different organs.

• Intestine: 3-5 Days
• Taste Buds: 10 Days
• Lungs: 2-3 Weeks
• Skin: 2-4 Weeks
• Red Blood Cells(RBC): 4 Months
• Liver: 5 Months
• Nails: 6-10 Months
• Hairs: 3-6 Years
• Bones: 10 Years
• Heart: 20 Years

Which Cells don't renew and cause ageing of human body

Yes, there are some cells which don't renew themselves and remain same for entire lifespan of human body. Some of those important cells/organs are listed here.
Brain: Its the most important organ our body mainly composed of neuron cells, which are never renewed. The neurons once generated remain same for entire life span. Usually we have around 100 billion neurons in our brain at the time of birth and their number remains same for whole life and most of them are not regenerated in complete life. However in some parts responsible for smelling sense and learning ability the regeneration may happen.
Heart: Previously it was thought that heart cells can't regenerate and don't renew themselves, but some recent studies have shown that there are some dots of stem cells in heart which helps in regeneration of complete heart in 20 years which is a very long duration. So in an average lifespan it is renewed around 4 times. But 20 years is a long duration and bad lifestyle is sufficient to damage it within that time frame.
Eye: Cells in our eye are not regenerated. It remains same from birth till death. However the upper transparent layer known as cornea can recover from any damage within 24 hours. But still our sight is affected with age as the lens loses its flexibility.
Skin: However outer layer of skin known as epidermis is constantly renewed in every 2-4 weeks, but still we get wrinkles as we age. It is because our skin loses collagen and elasticity with age.
Bones: As we age the regeneration of bone cells is slowed down. All the time our bones are a mixture of old and new cells. Due to slow down of regeneration process with increased age, the bones become thinner and diseases like osteoporosis sets in.

Diseases that affect Cell Regeneration

Emphysema: This is a dangerous lung disease which creates permanent holes in walls of lungs and it can stop the regeneration of cells as it begins with the destruction of the alveoli.
Smoking: Smoking can cause inflammation in taste buds and can damage them so much that their ability to regenerate is adversely affected.
Cirrhosis: It is a liver disease mostly caused due to heavy drinking. Scar tissues are formed in parenchymal cells and permanent damage occurs to the liver and cell regeneration capability is very adversely affected. Liver is one of the most important organs in human body as it helps in removal of toxins from the body, therefore cirrhosis can be fatal sometimes.

Apart from the above mentioned diseases there are a number of other diseases and environmental factors that affect the cell regeneration process. Our suggestion is that you should treat your body like its your own. Listen to your body and keep it good enough to live a healthy and long life. The way you treat your body is how it will respond when you need it the most.