Neurobiology on sugar: "It's even worse than you think"

I ate so much sugar during the last couple of weeks that I need a break and a big one. I think it is going to last until February until those "European carneval donuts" become popular again. My addiction to them is one of the reasons February is such an awesome month. Since I am going on a break until then and giving my body some well-deserved sugar break, it is important to remind myself (and you) what sugar is doing not only to my body but to my brain too.

Some exercising is in order too because all that sugar somehow magically transformed to fat, all of it. My genetics has once again shown who is the boss in our little relationship and there is going to be some serious workouts if I want to get back in shape again. This kind of article might just be the motivation I need. Hopefully, it will help you too.

First of all, there is a huge difference between natural sugar that is found in fruits and vegetables and added sugar that is, well, added to foods that would not normally have it. Added sugar is one of the main ingredients in candy, processed foods, soft drinks, and baked products. Yes, there is sugar in even the bread. It is everywhere. According to the American Heart Association, the amount of added sugar you should eat per day is 150 calories (37.5 grams) if you are a man and 100 calories (25 grams) if you are a woman. Here comes the plot twist, one regular-sized Snickers bar contains 120 calories from sugar. The math is simple, we are screwed.

The biggest problem lies is high-calorie beverages that do not make us feel full when we have them as we would if we took the same number of calories in food and keep in mind that those calories do not include fiber and other important nutrients from food. When we drink sugary drinks, our bodies respond to that sugar by producing triglycerides and some of them get stored in the liver while others get exported into the bloodstream. Research has suggested that our bodies process liquid sugar differently than sugar in foods. The lack of fiber makes the journey from liquid sugar to blood sugar much faster

Consuming too much added sugar over long periods of time affects the natural balance of hormones in the body. Levels of glucose in the bloodstream get increased which leads the pancreas to release insulin. Those higher levels of insulin cause the body to store more food calories as fat and they also affect a hormone leptin. Leptin is important because it is our natural appetite suppressant. It tells the brain we are full and should stop eating. High consumption of certain sugars has been linked to leptin resistance where the brain no longer gets the message that a person is full which leads to weight gain and obesity. To make things even worse, those with leptin resistance feel sluggish and it is more difficult for them to be active which continues the weight gain.

When we eat too much sugar, it leads to chemical changes in the limbic region of our brain (reward center) and characteristics of craving and withdrawal are produced just like with any other addictive substance. Yup, that's right, most of us are addicted to sugar and not even aware of it. Scientists at the U.S. National Institute on Drug Abuse were first to show that sugar causes changes in peoples' brains that are similar to those in people addicted to drugs. There is plenty of research now on the potentially addictive properties of sugar. You can check one of those here:

The research confirms the presence of neural adaptations including changes in dopamine and opioid receptor binding, enkephalin mRNA expression and dopamine and acetylcholine release in the nucleus accumbens. Too much sugar can lead to cravings and even MRI scanners showed how the same areas of the brain are activated when people crave either junk food or drugs. When the brain gets flooded with dopamine, a protective mechanism starts and the brain reduces its number of dopamine receptors (downregulation). This produces tolerance and like with any drug, a person needs progressively larger and larger doses. This is why I urge you to check these studies too:

There was a study by Duke University researchers that showed how a sugar habit changes specific brain circuits which produced cravings that reinforce the habit. A vicious circle indeed. They got a group of healthy mice hooked on sugar and compared the brains of the sugar-dependent mice to another group of healthy mice not hooked on sugar, focusing particularly on basal ganglia. That brain network is traceable along two main pathways: the first one that carries a “go” signal which triggers action to pursue the object of the addiction and the second one that carries a “stop” signal which puts the brakes on the pursuit.

Not only did the mice addicted to sugar have a more active go and stop signals but the go signal consistently appeared before the stop signal. Their brains lost the braking capacity to regulate their behavior. The brain circuitry changes were so strong that the researchers could predict which mice became hooked on sugar just by examining samples of their brains. Changes in their brains produced a strong signal to get more sweets and the mice continued pursuing sugar even when it was gone portraying a craving behavior. You can read the full study here:

According to a study funded by the National Institutes of Health, fructose may be doing a widespread of damage to our genes. More than 20,000 genes were examined to find if they get affected by fructose which results in changes to brain function and metabolism. More than 200 genes in the hippocampus and 700 in the hypothalamus are sequenced. According to Xia Yang, co-senior author of the study and a UCLA assistant professor of integrative biology and physiology, “Parkinson’s disease, depression, bipolar disorder, and other brain diseases” are all potential outcomes from gene disruptions caused by fructose.

Previous research already found that fructose increases levels of toxic molecules in the brain that damage communication between cells but now the UCLA researchers reported that they were able to identify the mechanism by which they were damaged. It is done by altering one of the four nucleotides that make up DNA. Diets high in fructose trigger the genes’ “on” or “off” switch, altering their function. Remember the on and off thing from the previously mentioned research? Yup, that's it. They had a control group that drank only water and one that drank water with fructose. The rats were then trained to run a maze, and the results showed that it took the fructose-consuming group twice as long to navigate the maze as the water-only group despite the same level of training which indicates impaired memory. The fructose rats had higher blood glucose, triglycerides and insulin levels. You can read the studies here:

Even though experiments that I was talking about were conducted on rats and more research is needed, the majority of the sequenced genes are comparable to those in humans and we can conclude how all of these findings hold a great value to our understanding of fructose and added sugars in our diet.

My advice? Avoid it.

If you are interested in learning more on this subject, check out these REFERENCES:
_{Over time, too much liquid sugar can lead to serious diseases from ucsf.edu
Added sugar is hiding in 74% of packaged foods from ucsf.edu
Too much fructose can damage your liver, just like too much alcohol from ucsf.edu
Dietary Sugars Intake and Cardiovascular Health-A Scientific Statement From the American Heart Association from ahajournals.org
The growing concern over too much added sugar in our diets from cell.com
10 Similarities Between Sugar, Junk Food and Abusive Drugs from healthline.com
Why Breaking Habits Is Even Harder Than We Think from forbes.com
Diets Heavy In Fructose Damage Genes Related To Memory And Metabolism, Says Study from forbes.com
Daily Intake of Sugar — How Much Sugar Should You Eat Per Day? from healthline.com}

Until next time,
KEEP YOUR SMILE ON!

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