Your Brain on Sugar
What is Sugar?
Sugar is the everyday toxin. We are constantly bombarded with messaging that sugar is bad for us. The truth is that sugar is likely the number one toxin human beings are exposed to in the modern-day. Sugar is generally a carbohydrate that the body uses as fuel to make energy in our cells. All carbohydrate-containing foods are composed of some form of sugar, and many different types of sugars exist including glucose, maltose, lactose, fructose, and dextrose. Ultimately, the body uses carbohydrates and all forms of sugar to convert into glucose which is the primary fuel source for our cells. And the body will not differentiate if you are consuming “good” sugars in the form of fruits, vegetables, and grains, or whether you are consuming “bad” sugars in the form of processed foods like sodas, candy, crackers, baked goods, etc. Ultimately, your body will convert any form of sugar you consume into glucose.
Sugar Consumption Realities
Humans have been thriving on sugar for centuries, and to an extent, sugar is essential for the production of energy in our cells, especially brain cells. Without a constant supply of glucose to the brain, one may not survive. So what is the big deal about sugar? We are consuming way too much of it. The average American eats 152 pounds of sugar annually. This is a stark rise from 1882 when we were eating just 6 pounds per capita. Just in the past 50 years alone, sugar consumption has tripled. And reasons for this are not surprising, given the highly addictive nature of sugar. The sweetness of sugar stimulates the reward pathways in the brain and has you coming back for more and more. In fact, research done by Serge H. Ahmed shows that the sweet taste is 8 times as addictive as cocaine. Rats offered IV cocaine versus artificially sweetened water always went for the sugar, and previously cocaine-addicted rats switched to the sweetened water. https://pubmed.ncbi.nlm.nih.gov/17668074/
If that’s not enough to confuse your sweet tooth, in a 2012 publication in Nature, The Toxic Truth About Sugar”, Robert H. Lustig argues that sugar should be a controlled substance like alcohol and tobacco.
Your Brain on Sugar
We have known for years that diets higher in sugar and carbohydrates increase one’s risk for metabolic disorders like diabetes and metabolic syndrome. However, a wealth of research is now linking blood glucose levels with risks for brain-related disorders, including dementia. Research shows that type 2 diabetes doubles your risk of developing Alzheimer’s disease. The main focus of this research relates to the effects of higher carbohydrate consumption and particular areas of the brain involved in learning and memory, like the hippocampus and amygdala.
Even higher normal fasting blood glucose (not even in the diabetic range), seems to be associated with more atrophy of the hippocampus and amygdala.
And it is not just glucose that is the culprit. Insulin, your fat-storage hormone and the hormone involved in the transfer of glucose into the cells, seems to have a significant role to play as well. Particularly, deregulated brain signaling of insulin seems to be a key player in the pathogenesis of Alzheimer’s Disease.
This deregulated signaling of insulin in the brain occurs once insulin resistance sets in, and the higher carbohydrate and sugar consumption, the higher the risk for insulin resistance. Insulin resistance and ultimately diabetes are now known to be risk factors for Alzheimer’s disease.
Research also points to how higher sugar diets change gene expression in the brain in ways that promote more cognitive decline. In particular, the expression of one of the most important growth factors involved in neuroplasticity, brain-derived neurotrophic factor (BDNF), seems to be reduced in the setting of higher sugar diets.
So a combination of higher glucose concentrations, impaired insulin signaling in the brain, coupled with impaired gene expression of vital growth factors creates the perfect storm for brain atrophy and ultimately cognitive decline and frank dementia.
How to Protect the Brain From the Impacts of Sugar
First and foremost, get more knowledgeable about where sugar is hiding. Believe it or not, sugar is masquerading around in dozens of hidden forms, from cane sugar to corn syrup, date sugar, dextran, dextrose, ethyl maltol, fructose, lactose, maltodextrin, maltose, rice syrup, and sucrose, just to name a few. Beware of the following foods and their high potential for hidden sugar:
Eliminating processed foods will significantly reduce your consumption of hidden sugars. Your goal should be to eat a mostly plant-based diet, high in vegetables and fruits with some grains, fish, and organic, pasture-raised meats as condiments. Sticking to the 75/25 rule helps keep perspective on this: make sure 75% of your plate is filled with colorful vegetables, while 25 of your plate consists of meat, fish, and grains. And don’t forget to incorporate healthy fats throughout the meal.
Complex sugars that occur naturally in starchy vegetables, fruits, and whole grains have properties that make them a wiser choice than simple sugars. Complex carbohydrates and sugars are higher in fiber, making them more slowly digested, with a slower and steadier release of insulin. Fiber is a superstar in and of itself too since it is beneficial for the microbiome or gut ecology. And a better microbiome equates to a better metabolism, less inflammation, and a better gut-brain connection. Lastly, complex carbohydrates are coupled with anti-oxidant and anti-inflammatory bioflavonoids and phytochemicals which synergistically help to optimize health and fight disease.
If you do consume carbohydrates, make sure to pair them with healthy fats and high-quality protein, and more fiber. This will also slow the absorption even more, keeping insulin and blood glucose levels steady.
Having a little sugar in your coffee, or having an occasional bite of a sweet treat on a special occasion may not be the end of the world. However, think of sugar as a recreational drug. If you find it difficult to break habits, be judicious about your choices.
How About Sugar Alternatives?
As already reviewed, artificial sweeteners are shown to be highly addictive. https://pubmed.ncbi.nlm.nih.gov/17668074/
On top of that, research suggests that even sugar alternatives increase your risk of obesity, diabetes, metabolic syndrome, and cardiovascular disease. And if that’s not enough, since these sugar alternatives are infinitely sweeter than actual sugar, they end up confusing your metabolism, by revving up insulin production and release. Sound advice would be to avoid most artificial sweeteners. The one exception may be stevia which comes from the leaves of the stevia plant. However, you should use it sparingly. A little in your morning tea or coffee should be fine, but make sure to choose a product that is 100% stevia without any additives.
In summation, while a treat here and there isn’t a disaster, to optimize your cognitive health for years to come, aim for a diet low in sugar and carbohydrates. I promise, there are plenty of healthy and delicious alternatives. Even better- your body and brain will thank you!