Halloween has passed. If your home is like mine, there was an abundance of leftover candy. We all have our favorites! However, this is a medical column, not a food column, so here is the question to address today: Is candy bad for our health? Let’s start with some scary facts. The average American consumes between 150 to 170 pounds of added sugar per year. That comes to, on average, 27.5 teaspoons per day per person, which translates to 440 calories - nearly one quarter of a typical 2,000 calorie a day diet. The key word here is “added.” While a healthy diet contains a significant amount of naturally occurring sugar (in fruits and grains, for example), the problem is that we’re chronically consuming far more added sugar in processed foods.
Why is added sugar a problem?
Added sugar does not add nutrition. Sucrose, high fructose corn syrup, and other added sugars contain calories with no essential nutrients. This is why they are known as “empty” calories. There are no proteins, essential fats, vitamins or minerals in sugar. Sugar negatively impacts nutrition and health because it often ends up replacing other necessary foods.
Sugar is bad for the teeth. It does a great job providing easily digestible energy to bacteria in the mouth, which leads to tooth decay and other diseases.
Sugar is not a good source for long-term energy. We digest candy almost immediately because it’s composed primarily of simple sugars that require little breakdown. Sugar breaks down to glucose, which quickly enters the bloodstream. This triggers the pancreas to release extra insulin to turn the glucose into glycogen, used by the liver and muscles. After that sugar rush, blood sugar levels drop dramatically, triggering the release of stress hormones like adrenaline and cortisol, which in turn activate stored sugar supplies. Stress hormones are great if we’re in danger: they raise our heart rate, increase our blood pressure, make our stomach clench, but then leave us shaky and nauseated once our bodies realize that there’s no danger to respond to.
Sugar can overload the liver. Glucose is found in every living cell on the planet. If we don’t get it from the diet, our body will produce it. We do not, however, produce fructose, and our bodies treat it differently. In small amounts, the liver turns it into glycogen and stores it. However, if the liver already has enough glycogen stored, additional fructose is turned into fat. This can lead to fatty liver and, of course, obesity. (Interestingly, this does not happen when large quantities of fruit are consumed.) Fatty liver is one of the leading causes of cirrhosis.
Sugar can lead to insulin resistance. Insulin is critical because it enables sugar in the bloodstream to enter cells, and instructs the cells to burn glucose instead of fat. When metabolic dysfunction occurs, insulin stops working properly and cells become resistant. This triggers the pancreas to produce more insulin. As insulin resistance progresses, the pancreas can’t keep up with the demand. Blood sugar levels rise, and diabetes can result. Does eating sugar actually cause diabetes? For the most part, type 2 diabetes is an inherited genetic disease. There is plenty of data, however, suggesting that eating large quantities of sugar leads to obesity and metabolic syndrome, which significantly increase the odds of diabetes.
Sugar may be addictive. It appears that eating sugar triggers a release of dopamine, a neurotransmitter that helps to control the brain’s reward and pleasure centers. This is likely not true for everyone, but those who have a susceptibility to addiction can become strongly dependent on sugar and other junk foods.
Sugar is a leading contributor of obesity. As expected, those who eat the most sugar are also the most likely to become overweight. This is true for all age groups, but the link is strongest for children. Sugary foods and drinks tend to be high in calories but not all that filling, making them easy to over-consume.
Sugar suppresses the immune system. Numerous studies have shown that when we consume large doses of sugar, we temporarily depress the immune system. The effect lasts for several hours, so if we eat sweets several times a day, our immune system may be perpetually operating at a disadvantage.
Sugar, rather than fat, may drive hypercholesterolemia and heart disease. Saturated fats have been blamed for decades. Large amounts of fructose can cause elevations in triglycerides, elevations in the bad cholesterol LDL (low density lipoproteins), and oxidized LDL, raise blood glucose and insulin levels, and increase abdominal obesity. All of this adds up to heart disease.
Sugar has been implicated in depression and dementia. Research has linked sugar consumption to low production of brain-derived neurotrophic factor (BDNF). BDNF is important in forming new memories, and in recalling old ones. Levels of BDNF are particularly low in people with an impaired glucose metabolism (those with diabetes or pre-diabetes), and as BDNF levels decrease, sugar metabolism gets worse. Research has also linked low BDNF levels to depression and dementia. Watch for more research on this subject.
The bottom line? Not everyone has trouble with added sugar in the diet, but it can clearly be harmful. The World Health Organization suggests that we limit our sugar intake to no more than 10% of total calories. For a 2,000-calorie diet, that would come to 50 grams of sugar per day. For those with existing health issues, such as metabolic syndrome, diabetes, obesity, and heart disease, that number should be much lower. For most of us, moderation is the key!
Dr. Alan Frischer is former chief of staff and former chief of medicine at Downey Regional Medical Center. Write to him in care of this newspaper at 8301 E. Florence Ave., Suite 100, Downey, CA 90240.
Published: Nov. 13, 2014 - Volume 13 - Issue 31