You can see it all around you. The rusty knife in the picture does not cut as well as a new one. The steel has been physically changed. If the rust problem gets worse, the knife can become weak and break. You can see that part of the edge is gone. A knife is made of iron. Rust is iron oxide. Oxidizing iron interferes with knife function and ultimately destroys the knife.
Human cells are the same. Yes, oxygen is essential to life. We die without it in minutes. But superoxide is oxygen that has been changed so that it attaches to anything in the area. It is an oxidant. When it combines with iron it creates iron oxide or rust. In the cell, oxidants combine with proteins, DNA and other critical components. That degrades the structure and function of the cell. Those cells don’t work as well. DNA oxidation causes strand breaks and mutations. That is a critical factor in cancer formation and progression. Proteins are involved in regulating the genes and chemistry in the cell. Oxidation changes the shape of the protein so that it can’t effectively regulate these processes. Oxidants activate processes that cause programmed cell death, cell growth, and inflammation. Oxidants are the key drivers of aging.
Some people age more rapidly than others. You have seen it yourself. Some people are 50 and look 80. And it is not just appearance. I had a patient who was 89, walked the golf course, and shot his age twice. Some people in their 60s are in a nursing home. We used to think that we just wear out and we have no control over the process, but that is not true at all.
The more you use and sharpen a knife, the quicker it wears out. The more you use your body and brain, the longer it remains fully functional. Now that we understand the biology of aging, we can slow it down. Exercise reduces oxidant damage. Diet and staying slender reduce oxidant production. A big meal increases oxidants. Processed food has had the antioxidants milled out. A single puff of cigarette smoke contains ten to the fifteenth oxidative particles. Lifestyle can make a big difference. There are also medications for aging-related diseases that are antioxidants that work to slow aging and chronic disease progression. Lisinopril, losartan, spironolactone, and eplerenone for hypertension, statins for cholesterol, and metformin for diabetes all fit into this category. Combining these medications in diabetes prolonged life and delayed complications by 8 years. That is proof positive that we can slow aging and delay chronic disease. We can keep our ability to do the things we love longer. Let’s get started!
Love this comparison and makes perfect sense. Appreciate the advice and approachable science so that I might teach others.
Thanks Jeff. Your comment means a lot to me. The knife in the picture is really interesting. It is an ancient Roman piece. It is remarkable how much it resembles the knives in my kitchen.