There’s another peculiar, and startling, hazard connected with high blood sugar that most people are quite unaware of, and it has serious implications for increased degenerative brain diseases, including Alzheimer’s. High levels of blood sugar can make your entire body, including your brain, age faster, which is hardly a happy thought. In short, high circulating levels of blood sugar, as well as eating lots of sugar, can harm your brain by accelerating the aging process through chemical reactions in cells.
Leading expert Anthony Cerami at the Picower Institute for Medical Research in Manhasset, New York, explains that glucose in the blood reacts with proteins to create aberrant so-called “glycated or cross-linked proteins”—a kind of cellular debris that accumulates in cells, mucking up their mechanisms. These sugar-damaged proteins turn yellowish-brown, and are also called AGEs (advanced glycosylation end products), which is appropriate because they accelerate aging.
They cause bones to “yellow,” joints to stiffen, blood vessels to toughen and become clogged, and organs, including the brain, to malfunction. The process, says Dr. Cerami, resembles what happens to a chicken when you roast it in the oven. Its skin gets browned and crispy. We, too, are undergoing this “browning process” at body temperature as we age. “Basically, we are cooking very slowly over our lifetime,” he says. In nerve cells, this browning process is not pretty.
These AGEs are just as dangerous to the brain as damage from oxygen-free radicals. In fact, AGEs compound their destruction by generating free radicals.
Researchers trying to solve the mysteries of human aging have known about AGEs for some time, and mainly blamed them on circulating levels of glucose in the blood—the higher the glucose, the greater the production of AGEs.
The sugar-damaged proteins are extremely high in the blood of diabetics, for example. Indeed, German researchers say that AGEs are the first step leading to diabetic nerve damage known as neuropathy. Researchers also believe this “glycation” process is a culprit in the destruction of brain cells leading to neurodegenerative diseases, including Alzheimer’s, and possibly even in age-related memory loss.
A leading researcher, Siegfried Hoyer at the University of Heidelberg, proposes that some forms of Alzheimer’s are tied to abnormalities in the way the brain metabolizes glucose, resulting in the overproduction of nerve-damaging AGEs, free radicals, and the formation of neurofibrillary tangles that kill off brain cells.
What’s new and alarming is that some researchers now say the risk of creating these destructive AGEs rises from consistently eating a diet high in simple sugars, independent of the blood glucose rises triggered by sugar intake. Roger B. McDonald, at the University of California at Davis, first showed that rats fed sucrose (ordinary table sugar) for most of their lives have shorter lifespans than rats fed comparable calories in starchy carbohydrates. In searching for the reason, he found that a high-sucrose diet created more AGEs. Indeed, he noted that the sucrose consumed, not blood glucose levels, mainly determined how many destructive AGEs were created.
In other animal studies, Israeli researchers discovered that eating excessive fructose may be even worse than eating sucrose or glucose. In a recent study, rats feasting on fructose showed the most damage from the sugar-protein reactions compared with those on high-sucrose or glucose diets. This is especially bad news, because in the last few decades consumption of fructose has skyrocketed, mainly due to the widespread use of high-fructose corn syrups in processed foods. Such fructose is used to sweeten soft drinks. That alone gives fructose extensive access to human brains, including young formative brains.
According to the Center for Science in the Public Interest, in 1996 the average American drank over 53 gallons of soft drinks!—up 43 percent since 1985. That’s compared with twelve gallons of fruit juices and twenty-seven gallons of milk. A twelve-ounce can of non-diet cola boasts ten teaspoons of sugar, usually in the form of high-fructose corn syrup, and 150 calories. Although the use of artificial non-caloric sweeteners is also way up in recent years, sugar is still the primary sweetener by far.
Important antidotes: You can reduce sugar-inspired brain-damaging “glycation” by taking the supplement alpha-lipoic acid, says Dr. Lester Packer at the University of California at Berkeley. That’s one reason lipoic acid seems to help prevent the onset of diabetes and its complications, notably neuropathy, he says. Recommended dose for diabetics: from 300 to 600 milligrams of alpha-lipoic acid daily.
Dr. Cerami has also recently discovered that alcohol partially blocks the AGE formation. AGEs dropped 52 percent in diabetic rats given some alcohol daily for four weeks compared with rats not given alcohol. Dr. Cerami surmises this is one reason drinking some alcohol reduces risk of cardiovascular disease.
BOTTOM LINE: High blood levels of glucose as well as high intakes of sugar and fructose may lead to sugar-damaged proteins and nerve destruction. Remember: The brain was not designed to accommodate such consistent overloads of modern sugary foods and, understandably, may react badly.
Skimping on chromium could put you in the doldrums and steal your memory. A reason: Chromium helps regulate blood glucose. Indeed, a chromium deficiency in some individuals fosters impaired glucose tolerance and decreased number of insulin receptors (needed to process blood sugar), hypoglycemia, as well as high cholesterol and triglycerides.
Dr. Richard Anderson at the U.S. Department of Agriculture says chromium tends to normalize blood sugar—raising or lowering it, as needed. His research showed that 1000 daily micrograms of chromium reversed glucose intolerance and symptoms of diabetes. He recommends 200 micrograms of chromium daily to normalize blood sugar and prevent insulin resistance and diabetes in healthy adults.
Larry Christensen, Ph.D., chair of the psychology department at the University of South Alabama, says that people with major depression often have disturbances in processing glucose and consequently have exaggerated glucose responses, twice that of normal people. They also often have a marginal chromium deficiency. He says this chromium lack is compounded by the fact such persons often eat lots of sugar, perhaps in efforts to reverse their depression. But sugar depletes chromium, perpetuating a vicious circle that actually promotes depression.
In double-blind studies, Dr. Christensen found that a long-time high-sugar diet could promote persistent fatigue and depression in some people. In some individuals, he says, eating sugar creates a vicious cycle of mood swings, with a temporary burst of good feeling, followed by a downswing as blood sugar and the brain chemical serotonin fall. To raise their spirits they load up on more sugar, which again, after dives and rebounds in their blood sugar, makes them feel worse. The only long-term solution: Eat sugar sparingly or not at all to smooth out the sugar-inspired roller-coaster moods, advises Dr. Christensen. Taking chromium may also help.
Since chromium can help alleviate poor glucose control that impairs mental function, it’s definitely a “brain-boosting” nutrient.
HOW A HIGH-SUGAR DIET CAN BE BAD FOR YOUNG BRAINSSugar replaces high vitamin and mineral foods, creating a deficit in nutrients the brain needs to function optimally.Some studies find that kids on high-sugar diets do worse on
IQ tests, get poorer grades, and have more mood swings.Certain children, such as those with attention deficit disorder and hyperactivity, are often super-sensitive to high sugar intakes. PET scans show their brains do not burn glucose as efficiently. High blood sugar stimulates a greater release of cortisol—the “fight or flight” hormone—in such children.A chronic high intake of refined sugar at an early age is associated with poor attention spans in both normal and hyperactive children.
High intakes of simple sugars, found in soft drinks and other processed foods, cause cellular damage (AGEs or glycation) in animals, known to promote nerve damage, premature aging in animals, and possibly degenerative brain diseases including Alzheimer’s.
BOTTOM LINE: Try to keep blood glucose at normal levels for both good intellectual function and good moods. Best way to do that: Eat in ways compatible with your brain’s evolutionary desires—choose low glycemic index carbohydrates that gradually raise blood glucose, making it steadily available to your brain. Cut back on sugar that may independently undermine good mental functioning and damage brain cells.
