July 24, 2009 by Danielle Charles
Though some certainly have more of a sweet tooth than others, I think it’s fair to say that we have all come face to face with the powerful allure of sugar. The taste of sweet is, after all, the most basic and instantaneous pleasure we know. It is the first taste we learn to recognize and prefer in our mother’s milk, and we forever associate it with that sense of nourishment, comfort and love. The imagery and symbolism of sweetness in our culture reflects this. We use the word “sweet” to denote something which is pleasing to the mind, wholesome and gentle. Just look at the image below – what is the first thing that comes to your mind? It brings me right back to my Mom’s kitchen, a feeling of warmth and comfort, all infused with a childlike innocence and wholesome pleasure.Throw in some chocolate and raspberries, however, and now the pleasure takes on a more grown-up appeal. Suddenly it illicits words like “sinful” or “guilty pleasure.” This is the type of sweet we want to be alone with – to savor and even moan with delight over. Turns out we can find amorous love in sugar as much as we can find motherly love. We even call our significant others names like, “sweetheart”, “honey” and “sweetie.”
Beyond it’s purely symbolic allure , our brain has its own chemical romance with sugar. As soon as that sugar molecule comes in contact with the taste receptor on our tongue, neurons in our brains are stimulated to release dopamine – a neurotransmitter involved in reward pathways – which induces a temporary period of elation and bliss. This is our brain’s way of telling us that this substance we have put in our mouths is good, that we should eat more of it and keep feeling wonderful. The taste of sugar has also been shown to stimulate opioid release in the brain. Opioids are the brain’s natural pain reliever and sedative (certain chemicals in plants, especially the opium poppy, are also able to stimulate these receptors). The net result here is that sugar makes us feel happy and separates us from the experience of pain – think chocolate cake to quell your sorrows. Unfortunately, these effects don’t last long. We finish the cake, but the pleasure doesn’t last. The dopamine and opioid levels drop back to normal, and the elation is replaced with anxiety and a longing to return to that high once again.
So why is our brain telling us to love something so deleterious to our health? To answer this, we must think of our hunter gatherer ancestors, searching the landscape for plants that were nutritious and, hopefully, not poisonous. Sugars are generally produced in plants as an indication of ripeness and therefore peak edibility – think ripe berries (the unripe ones are distastefully sour). They also indicate the presence of abundant carbohydrates, and therefore high caloric content. Also, there are very few things in nature which taste sweet and are also poisonous. Thus, sweetness was really a signal for nutrition and edibility – and when we came in contact with it, our brain reinforced the idea we had come across something particularly good. In contrast, when we came in contact with something extremely bitter tasting, we were immediately repulsed. This is because bitter, unlike sweet, is often attributed to toxic substances such as alkaloids. Our body reacts to this taste by increasing gastric peristalsis, opening up the esophageal sphincter, and trying to make a quick exit of that substance back form whence it came - (this reflex happens on a milder level when we consume slightly bitter herbs and vegetables, with the result of actually enhancing digestion).
The problem is that our evolution never anticipated we would be standing in supermarkets surrounded by Twinkies, candy bars and soda pop. In nature, it would be completely impossible to consume the 158 lbs of sugar we consume in a year here in America (that is per person by the way). This is because nature doesn’t provide us with refined sugar ( except perhaps honey, which would’ve been a rare and difficult treat to procure). Sugar in nature is always found within a matrix of fiber – which slows the release of pure glucose into our blood stream and gives us a long and steady “slow drip” so to speak. It was also always found in combination with vitamins, minerals and other phytonutrients that supported the metabolism of sugar into usable energy and protected us from its inflammatory and damaging effects. Blueberries and other berries, for example, contain phenolic compounds that help to slow the absorption of their sugar content into the blood stream, enhance its metabolism into usable energy, and protect against the oxidative damage sugar can cause to our blood vessels. Even honey, nature’s refined sugar, is packed with enzymes, vitamins and minerals that aid it’s metabolism.
White sugar is an entirely different story however. Stripped of the fiber and micro nutrients that would slow and support it’s metabolism, white sugar dumps itself immediately into our bloodstream, causing a huge spike in blood sugar. Our body, used to times of feast and famine, sees that we have an excess of nutrition right now that can be stored for later. Insulin, the hormone which tells our cells to take up glucose, is dumped out by the pancreas in an attempts to balance this huge spike. The immediate result of this is a rapid drop in blood sugar, and we find ourselves in a hypoglycemic state that leads to more sugar cravings – the start of a viscous cycle. The long term result is that we keep storing sugar (largely as triglycerides, or fat) for a famine that never comes. Eventually, our body tries to balance this by producing less insulin, and responding less to the insulin that is there (ie insulin resistance). Enter type II diabetes.
The high levels of sugar in the bloodstream have numerous impacts on our health, however, before insulin resistance and diabetes sets in.
Inflammation: Glucose, like oxygen, is a very reactive molecule – it likes to attach itself to things, which tends to damage the thing it attaches to. It specifically likes to attach itself to proteins, forming molecules called Advanced Glycelated End-products. The body has to get rid of these, as they are non-functional, and repair the proteins. This taxes the body’s ability to repair and regenerate itself. Our cells have to rev up their rate of DNA transcription to produce the needed proteins and become far more sensitive to mutations that lead to cancer. When these glycelated proteins can’t be gotten rid of very rapidly, such as in collagen or nerve fibers, they accumulate and react with macrophages – setting up an inflammatory cascade. This plays a role in not only the development of atherosclerosis, cardiovascular disease and cancer – but in all types of inflammation – arthritis to eczema.
Immune Impairment: Glucose inhibits the function of the immune cells by disrupting vitamin C uptake in phagocytes, a type of white blood cell that engulfs and digests bacteria and viruses. This is because sugar and vitamin C are molecularly quite similar, and use the same transport channel into immune cells. When blood sugar is high, phagocytes take up sugar instead of the vitamin C they need to function. A blood sugar level of 120 will reduce the phagocytizing ability of white blood cells by 75%.
Nutrient Depletion: Sugar depletes many vitamins and minerals in its metabolism (which is why in nature it is always found in concert with them), including chromium, magnesium, zinc and B vitamins (interestingly, many nutrients also involved in nervous system health and mood regulation). This can play a role in many mood disorders – depression, anxiety, irritability, PMS, and contribute to fatigue.
Adrenal Dysregulation: Eating a large amount of glucose puts a significant stress on the body by rapidly shifting blood sugar levels. While there is one main hormone in the body to reduce high blood sugar, there are several hormones that are able to increase low blood sugar (demonstrating the rarity of high blood sugar in our evolution). These include glucagon, cortisol, epinephrine and growth hormone. Cortisol and epinephrine are produced by the adrenal glands in response to stress. They increase blood glucose levels so that our brain and muscles have enough energy to quickly deal with a perceived stressor (a sabor tooth tiger for example). When blood sugar plunges after a sugar binge, the adrenal glands are stimulated to release hormones as though we are dealing with a real stressor. You might notice that when your blood sugar drops, you start to feel anxious and your heart rate increases – a direct result of the stimulating effects of epinephrine on the sympathetic nervous system. When sugar binging become a regular pattern, the adrenals become taxed by repeatedly having to respond to the resultant drop in blood sugar levels. Sugar also depletes many minerals necessary to the production of adrenal hormones – particularly vitamin B6. Eventually this cycle will lead to adrenal depletion – with inability to maintain proper blood glucose levels, inability to deal with stress, and chronic fatigue.
Conversely, a high stress lifestyle will lead to blood sugar deregulation as well. Cortisol inhibits the effects of insulin – and can contribute to insulin resistance. Remember that stressful situations require high blood glucose levels to fuel our brain and muscles so we can think clearly and run away or fight. These days, however, we are rarely facing the type of stress we can run away from – and we fail to use that available glucose up. When we pair chronic stress with a high sugar diet, we have a recipe for type 2 diabetes.
Now that we understand a little about sugar, why we crave it and its impacts on the body, we can look at ways to quell our cravings and over-consumption. Stay tuned for part 2, which will cover dietary and herbal strategies to lesson sugar cravings and improve blood sugar balance.
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