By SUSAN CALLAHAN, Associate Editor and Featured Columnist
You have doubtless seen the headlines: “Sugar Makes You Age Faster” “Sugar Causes Wrinkles” and so on.
In the crime of aging, sugar is often one of the “usual suspects”. And, looking at the big picture from 50,000 feet above, if you will, the suspicion seems well-grounded. Excess sugar is a leading cause of the growing rates of obesity in the developed world. Then there is the rise of diabetes. For the first half of the twentieth century diabetes was a rare disease. But, that all changed with the invention of sugary sodas.
Since the start of the Age of Cola, sugar consumption turned so sharply upward that the graph looks like a hockey stick. In 1822, we Americans consumed the amount of sugar in a 12 ounce can of soda every 5 days. By 2005, we consumed that same amount every 7 hours, according to US Commerce Department data.
So, too, death rates caused by diabetes, heart disease and stroke have followed the same steep climb upward. Is sugar really the cause of accelerated aging? Is sugar the guilty party? What does the science say?
Unraveling the Mystery of Sugar -- Telomeres
We all know by now that, biologically speaking, each of us is really a walking-talking expression of our genes. Our genes are housed in threads of chromosomes. Each of us has 22 pairs of chromosomes plus a sex chromosome, XX for females and XY for males, bringing the total to 46 chromosomes for each human being. These little threads of chromosomes exist in every single cell of our bodies.
At the tip of each thread, there is a tiny cap. These caps are called "telomeres". As a cell ages, its telomere cap shortens and shortens until the chromosome becomes totally unprotected, and dies. Thus, a shortening telomere is in a real sense one of the best measurements for how old that cell is.
One type of cell which has drawn the interest of scientists studying aging are white blood cells (leucocytes). Your white blood cells are fierce soldiers in your immune system. White blood cells “patrol” the borders of your body and are the first responders to an attack by invasive bacteria or fungi. When you get sick, it is your white blood cells which spring into action, devouring bacteria and fungi that have invaded your body.
Because of their critical role in keeping you alive, white blood cell count has become a proxy of sorts for how robust your immune system is. Scientists have also used the aging of your white blood cells are a pretty good proxy for how fast you are aging overall as well.
What studies have found in that many things can shorten a telomere, and thus hasten a cell’s death. But what those telomere-shortening stresses actually are is a subject of considerable debate among scientists.
Some argue that one of the most corrosive things you can do to your tiny telomeres is to expose them to sugar. But is it true? What evidence is there, really?
Sugar May Not Be the Culprit in Telomere Shortening
Here is some of the evidence. In 2014, Dr. Cindy Leung and Dr. Barbara Laraia of the University of California, San Francisco and the University of California at Berkeley led a study of white blood cell telomeres. Scientists have long known that people with diabetes or who do not control their sugar intake have significantly higher risk for heart disease. The 2014 study sought to discover whether telomere shortening in the presence of sugar is the underlying reason.
To test their theory, the scientists set out to discover the link, if any, between white blood cell telomere length and consumption of sugary sodas. After examining the health surveys of 5309 non-diabetic adults between the ages of 20 and 65, they divided the participants according to their consumption of fruit juices, diet sodas and sugary sodas. They then measured the white blood cell telomeres of all participants.
What they discovered was that those people who drank the most sugary, carbonated sodas also had the shortest telomeres.
Drinking diet sodas had no effect on telomere length. And drinking 100% fruit juices actually seemed to protect telomere length.
Finally, drinking non-carbonated sugar drinks also had no effect on telomere length. This last result contradicts the theory that it is sugar, and sugar, alone which shortens telomeres.
And likewise, the finding that telomeres are actually lengthened in those who drink 100% fruit juices makes no sense if sugar is the culprit because fruit juices are high in sugar also.
The scientists conclusion was, therefore, measured: “Regular consumption of sugar-sweetened sodas might influence metabolic disease development through accelerated cell aging.”
Note the use of the word “might”. That nuance was lost in some of the hyped coverage of this study, with headlines blaring that the study proved that “sugar makes you age”.
We believe that sugar does in fact accelerate aging but you can’t make that case from this much-touted California study, try as you might.
But other studies do seem to point the finger directly at sugar as the culprit in telomere shortening and your aging. A 2012 study conducted jointly by researchers from Lund University Diabetes Center, Lund University, in Malmö, Sweden and the Department of Nutrition, Harvard School of Public Health, Boston, MA found that telomeres shortening is strongly linked with high blood sugar concentrations. Specifically, the study linked shorter telomeres with postprandial sugar levels, the blood sugar levels that occur 2 hours after eating.
High postprandial sugar levels is a marker of diabetes.
Not surprisingly, other studies have found a direct link between short telomeres and your risk for developing diabetes. A well-controlled study in 2009 from researchers at Brigham and Women’s Hospital, Harvard Medical School, found a strong association between average telomere length and Type 2 diabetes in white participants.
Does a Low-Sugar Diet Extend Your Life?
If sugar in your blood is associated with having shorter telomeres, then does eating a low-sugar diet extend your telomeres? The answer is “maybe”.
Feeding mice a low-glycemic diet extended their life, according to a 2013 study from the University of Ballarat, in Australia. Low-glycemic index foods are foods which do not raise your blood sugar levels after consumption. Proteins, most non-starchy vegetables such as greens (spinach, collards, broccoli, bok choy, string beans and so on), peppers and whole grains all make up a low-glycemic index diet.
In this experiment, scientists started with older, aged mice. They then fed a group of them a low-glycemic diet. Compared with the control group, the diet-fed mice had 12% longer lifespans. That is not insignificant. On a human scale, if an average lifespan is 80 years, then adding 12% to it would extend the lifespan to 96 years.
So, yes, the low-glycemic diet added “years” to their lives but when the scientists looked at the telomeres, they found something surprising. The average telomere length was not longer in the low-glycemic diet group. What gives? The scientists speculated that maybe the mice were already too old. They surmised that perhaps if the mice had started on a low glycemic diet earlier in their lives, they might have shown shorter telomeres.
So, the good news is it’s never too late in life to benefit from a low-glycemic diet. Doing so can extend your life by as much as 12%. The bad news is, if you wait too long, a low-sugar way of life may not help your telomeres one bit.
What do we make of these seemingly conflicting studies? One way to reconcile the studies is to conclude that, yes, having high postprandial blood sugar levels does in fact shorten your telomeres. But having high postprandial blood sugar really only means that your body is unable to properly process sugar --you are diabetic or you have insulin resistance. It does not mean you have eaten too much sugar. If you are one of those people with a properly working insulin response, then excess sugar will be processed away in a short enough time to do no harm to your telomeres.
Also, if your insulin sensitivity is not calibrated properly, then eating a low-glycemic diet will in fact improve your body’s ability to handle sugar, and thus protect your telomeres.
Inflammation Is the Key to Rapid Aging
It’s clear that another, more powerful process than simple sugar-eating is at work. And that process is inflammation.
What do diabetes, arteriosclerosis, heart disease and stroke all have in common? That all start at the cellular level with internal inflammation.
Inflammation is the cause of telomere shortening, rather than the simple presence of sugar, according to a 2013 study from University College London. Led by Dr. Klelia Salpea, this laboratory-dish study looked at how cells called fibroblasts reacted in an environment designed to induce inflammation as opposed to a high sugar diet.
What the team found was that the fibroblast telomeres shortened in a pro-inflammatory environment but not in an non-inflammatory environment with sugar alone.
So, this is the “aha” moment when the detective solves the crime: Low-glycemic eating extends the length of life -- in mice at least -- because it lowers the amount of internal inflammation, which in turn protects telomeres from deterioration. And you therefore age slower.
Eat low-carb, low sugar, high greens and vegetables and high quality protein (oily fish such as salmon, tuna, halibut, sardines and mackerel with added meat to keep your iron levels healthy, beans and eggs).
We will need many more studies like this one from London before we can settle the question of sugar’s role in aging but the early evidence is that sugar is not the guilty party. Inflammation’s fingerprints are on the trigger.