Have you ever wondered why sugar has such a stranglehold on society? Sure, it tastes good, but that isn’t enough to explain why we tend to crave sugar and go out of our way for it. We know it isn’t good for us, and can lead to being overweight, diabetes, and even cancer — yet we are still drawn to it. Can we go so far as to say some of us are addicted to sugar? It’s not surprising if you are: there are powerful forces at work in your brain that drive your desire for sugar and simple carbs which break down quickly into sugar.
You probably know how sugar drives up insulin, which takes the sugar for use in your cells and causes excess to be stored. You realize that insulin levels kept too high for too long is the main driver of obesity and diabetes. Knowing this, you try to cut back – that’s when you realize it’s not easy to do so. Something down deep says that you can just have one more sweet and you’ll be satisfied – except you’re not satisfied for long. Your body has all the sugar it needs, so what is causing you to crave more? The answer lies in the neurotransmitters in your brain. Neurotransmitters are necessary to make your brain function, but when they get out of balance, trouble follows. Let’s consider the two primary neurotransmitters which are key to handling your diet.
Serotonin – the calming brain chemical
Serotonin is considered an inhibitory brain chemical. It quiets your mood and is necessary for relaxation. When your serotonin is low, you are not restful: you may have trouble sleeping, trouble thinking clearly, are often feeling angry, and are likely to crave carbohydrates. Low serotonin leads to depression and a loss of pleasure. These effects are happening in the brain, but there is another aspect to serotonin that happens in the pancreas.
Serotonin is also critical for the production of insulin. In the pancreas, ?-cells (beta cells) synthesize serotonin and secrete it along with insulin. Published in PLOS Biology, researchers at the Max Planck Institute for Molecular Genetics in Berlin, Germany studied a process termed “serotonylation”, where they showed in animal studies that those that were not producing serotonin outside the nervous system became diabetic, and that this could be reversed by serotonin infusion. They verified the cycle: high serotonin levels inside the beta cells would cause secretion of both insulin and serotonin. Then the serotonin levels was high just outside the beta cells, but low inside, causing an inhibition of further release. This extracellular serotonin was slowly taken up by the beta cells, and they then secreted more insulin.
Serotonin is thus vital in the brain and the pancreas, and low levels can lead to sugar/carb craving. Serotonin levels need to be kept high enough to avoid this reaction. So serotonin is a piece of the mystery as to why we crave sugar and carbs – but there’s more…
Dopamine – the “get up and go” brain chemical
While serotonin is an inhibitory neurotransmitter, dopamine is (mostly) an excitatory brain chemical. Dopamine gives us motivation and mental focus. Since it is excitatory, it also is stressful to have the levels running high for long periods. When it is low, it leads to feeling tired, having poor memory and concentration, and little desire. It also has something in common with low serotonin: a tendency to crave carbs and sugar. That may seem odd – it is something of an opposite to serotonin, yet it can cause carb craving as well.
Dopamine is a “reward” chemical in the brain. This reaction is the partner to the motivation that dopamine promotes. When you work towards a goal, and then achieve it, dopamine gives you a rush of excitement, a reward for the success. This also kicks in when eating something that you enjoy, reinforcing the enjoyment with a desire for more. This can lead to an addiction cycle, where you want more and more of a food that you know is not a good choice.
Published in Nature Communications, researchers at the New York University School of Medicine conducted a study to see the dietary interaction of insulin and dopamine. They used a group on a low calorie diet and one on a high calorie diet and compared the two. Those on the low calorie diet had a 10 times greater sensitivity to insulin-caused release of dopamine in the brain than those on a high calorie diet. So the reward on the low calorie diet was easily achieved, while the high calorie diet made it harder for them to be satisfied with their food. As you can imagine, if they were already eating a high calorie diet and were less easily satisfied, they were even more likely to consume additional calories.
So while serotonin and insulin are related, so is dopamine related to insulin. We know that if insulin levels are high for long periods, insulin resistance occurs, where the cells simply do not respond as vigorously to the insulin anymore and higher levels are needed to achieve the same impact. We see from the study that high insulin also causes less reward signals in the brain, so it takes more food to get the same satisfaction. This is a negative cycle for both, which can readily lead to obesity and diabetes.
Published in The Journal of Clinical Endocrinology & Metabolism, a study at the Institute of Diabetes Research and Metabolic Diseases (IDM) of Helmholtz Zentrum München at the University of Tübingen, Germany measured levels of dopamine after administering insulin via a nasal spray, which brings the insulin directly to the brain. They observed a drop in dopamine levels immediately after the increased insulin. This simulates the effect after eating, when insulin levels normally rise. The natural result is that your feeling of reward is lower, and you want more food. Of course, you don’t want to pass up dessert!
We are seeing that insulin impacts both key neurotransmitters rapidly – eating has a major impact on your brain function. You may find yourself eating “comfort food” at times, because you realize that eating will impact your mood and focus. But the reward system doesn’t have any quality checking, and bad food can quickly turn the reward cycle into an addictive cycle.
Serotonin and dopamine should be in balance. One or the other may be dominant at a particular time, but neither should be depleted. A low glycemic diet will not throw them out of balance, but a high sugar/carb diet kicks up the insulin, shifts the neurotransmitter balance towards high excitement and a need to eat even more calories to gain more reward, creating an addictive cycle. We’ve experienced sugar highs, which lead to a craving for more while leading to a post-sugar crash. We attributed those effects to insulin, but more properly we should consider that this is an insulin/serotonin/dopamine cycle.
We need dopamine to get moving and get things done. We need serotonin to relax. Both are necessary so we are neither lethargic nor overdriven. With the standard American diet, most of us are already running in the addictive cycle, with our neurotransmitters telling us to continue the poor behavior. This works perfectly with our stressed-out lifestyle, pushing us further into this cycle, which is very short-sighted: don’t expect it to steer you into a healthful diet! Instead, you have to take control, and trade short-term hormone-driven rewards for the real reward of better health.
Dr. Nemec’s Review
Your brain is the controller of your body, your emotions, feelings and moods. What affects your brain? Your perceptions, attitudes and beliefs. What else affects your brain? Your diet immensely and especially your level of carbohydrates in your diet. Not all carbs are created equal. Greens in salad are carbohydrates, but are complex and raw/uncooked so these have practically no glycemic index and will not raise your insulin nor throw your neurotransmitters out of balance. Bread, pasta, potatoes, rice — even beans — have a higher glycemic index and can start the insulin rising and progressive neurotransmitter secretion that can begin the cycle of addiction. Since dopamine and serotonin are major players as far as brain chemistry and neurotransmitter levels we must know how we can shift these two into balance. Balance is the key because when one goes up many times the other goes down. So in these studies it was very evident that dopamine and serotonin are very connected to insulin secretion and insulin is secreted when carbohydrates, starches and sugars are consumed. The New York University School of Medicine study showed those on the low calorie diet had a 10 times greater sensitivity to insulin-caused release of dopamine in the brain than those on a high calorie diet. This means the amount of dopamine that was secreted on the low glycemic index diet was very adequate and functional at one tenth the amount: no addiction to be created here. Let me restate that another way. If you eat too much and especially too many carbs, starches and sugars then you will burn out your brain chemistry trying to play teeter totter with secreting way, way too much dopamine, then the serotonin has to go even further out of balance to try to compensate. The answer is not take drugs that stimulate neurotransmitter secretion, but change diet and lifestyle the way we have taught at Total Health Institute for the last 38 years. Moderation, not excess, is always better when it comes to health, healing and longevity.
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- Membership Program is our newest program offered for those that want to work on their health at a high level and want access to the teaching at Total Health Institute along with the Forums: both Dr. Nemec’s posts and other members posting. And also, to have the chance to get personalized questions answered on the conference calls which are all archived in case you miss the call. The Membership Program has 3 levels to choose from: Learn, Overcome and Master. The difference is at the Overcome and Master levels you received one on one calls with Dr. Nemec personalizing your program for your areas of focus.