by Barbara Berkeley, MD
One lovely side effect of weight loss is that it often makes you look younger. Sometimes significantly.
Apart from the fact that weight loss makes women appear less matronly and men less stodgy, there seem to be other more profound links between obesity and senescence. As I wrote about in an earlier post called The Age that Counts, the type of fuels you choose to eat can affect cellular functions that age you. In particular, too much sugar in the blood tends to deform proteins by a process called glycation. While we can't completely avoid the effects of glycation and free radical damage, we can tone them down significantly by eating foods that tend to produce fewer of them.
Recently, research is beginning to focus on a more direct effect of obesity: shortened telomere length. Telomeres are the little "caps" that sit at the ends of our chromosomes. These caps are often compared to the hard pieces that sit at the end of your shoelaces. They prevent DNA from fraying and getting damaged. But each time that a cell divides, the cap gets a bit smaller. When the DNA can no longer be protected, cancer is more likely and eventually cell death occurs. This is called cellular senescence. We are all the sum of our individual cells, nothing more. An excellent and fascinating review of telomeres can be found here.
It appears that being overweight is associated with decreased telomere length. This might well translate to accelerated aging. In addition, shorter telomeres mean a greater possibility of cancer. We know that cancers of almost all types are much more common in obesity people than in those at normal weight.
You can find a very interesting study that demonstrates the relationship between obesity and shortened telomeres here. In this study, the telomere lengths of 309 people, age 8 to 80, were examined. What researchers found was that increased weight was associated with decreased telomere length in all age groups and in both males and females. This shorter length was independent of individual variations in things like cholesterol, blood pressure and blood sugar. Perhaps most importantly: "The negative association of BMI with telomere length was stronger among younger than older participants (P for interaction, 0.03)." In other words, there might be a stronger effect on telomeres when one is obese and younger.
We tend to look for youth through processes of rejuvenation, searching for ways to revive a younger past. But this is pretty nigh impossible. What is possible, however, is to protect the body from known aging factors. These include glycation, smoking, inflammation and a too large fat mass.