How Too Much Sugar May Increase Your Risk of Alzheimer’s

For the entirety of my life, the standard diet recommended for most Americans has been a high-carbohydrate diet. By nature, this tends to increase our sugar consumption, since most of us do not opt for less sweet foods. On top of that, the processed food companies have quietly been adding sugar to nearly every food—making it nearly impossible, for example, to buy a loaf of bread without added sugar.

At the same that this was occurring, Alzheimer’s rates have skyrocketed, as have obesity and the underlying metabolic syndrome. At first, this seemed to perhaps only be a coincidence. But as more time has passed, and the data continues to roll in, it seems more and more that this excess sugar could be a cause of Alzheimer’s disease. Since Alzheimer’s is the third leading cause of death in the United States, this is a very serious issue.

About 1 in 10 people over age 65 have Alzheimer’s and those numbers are still increasing.

As Dr. Perlmutter outlined in his best-selling book Grain Brain, there are a wide variety of neurological issues which can be brought about, or are related to, the standard Western diet. And as Dr. Emily Deans from Harvard University recently wrote on, there is new evidence that a Western diet actually is related to smaller brain size.

(Watch: How The Food You Eat Changes Your DNA with Dr. Perlmutter)

Terrifyingly, there is no cure for Alzheimer’s disease, though interestingly, a small UCLA study last year highlighted that part of the memory loss could be reversed—for the very first time in history. How did researchers do this? By following a Paleo-like template. This was a landmark study, and the data continues to support the notion that a high-carb, and by nature, high-sugar diet may not be good at all when it comes to mental health.

And without mental health, what kind of health can we really have?

How Does Alzheimer’s Happen?

Alzheimer’s disease is endured by about 1 in 10 people over age 65—though those numbers are increasing. As we see the continued aging of the baby boomer generation (the first generation that really consumed an extremely high sugar diet for most of their life) we see the continued expansion of Alzheimer’s disease. From a science perspective, Alzheimer’s is typically first seen via problems with memory, judgment and thinking. There is even early-onset Alzheimer’s, which is particularly cruel, and was featured in the recent film Still Alice.

Alzheimer’s disease is your brain malfunctioning. Memory loss and dementia increase as Alzheimer’s increases, and while there are some medications to help with symptoms, there is no cure. Genetics seems to largely be a cause of Alzheimer’s, but increasingly it seems that epigenetics (i.e. your diet and lifestyle) also plays a major part in developing the disease.

Mechanistically, plaques and tangles are seen in the brain, leading to buildups that are problematic. Scientists are still debating what exactly causes Alzheimer’s, but there are a few different hypotheses. One of the first guesses was the cholinergic hypothesis, which basically suggested that the disease was caused by a reduced synthesis of the neurotransmitter acetylcholine.

Unfortunately, while a possible cause, it doesn’t seem all that likely, since drugs designed to target this area have not been all that successful. Other mechanisms of cholinergic effects have been suggested as well, such as a large buildup of amyloid. The thinking here is that this may lead to an “inflamed brain.”

As mentioned, genetics may play a role in the disease, and another common causative possibility that has been suggested is the Tau hypothesis. But perhaps the most relevant hypothesis here is the amyloid hypothesis, which states that the beta-amyloid protein (or a very similar protein) lowers synaptic function. In tandem with this, a protein called amyloid precursor protein binds to a receptor literally named death receptor 6 (DR6). This seems to be the most plausible theory, since DR6 is found in the brain areas most crippled by Alzheimer’s.

How Does Sugar Factor In?

At this point you may be thinking, how does sugar play a role in a brain disease? Well, the answer is multivariate. For one, the pathways that are involved in developing diabetes also seem to be affected when Alzheimer’s occurs. Since evidence tells us that too much sugar directly leads to diabetes, this is the first red flag.

Some scientific experts believe that too much glucose being burned, over time, may cause a disruption in your brain. This is also why approaches like the UCLA Alzheimer’s study, where a lower-sugar diet was consumed, seem to work—at least so far. In fact, Alzheimer’s disease was named “type 3 diabetes” because your brain can produce insulin, as well. The catch? This insulin is needed for the survival of your own brain cells. And if disruption of that occurs…well, you can see what would happen to those brain cells.

Another red flag is the fact that diabetics lose gray matter more than those who do not suffer from diabetes. Why is this important? This loss of gray matter is a contributing cause of Alzheimer’s. And if we refer back to Dr. Emily Dean’s article, we will see that there is now evidence that a Western diet is linked to a smaller hippocampus—one of the areas in your brain most affected by Alzheimer’s. Things aren’t looking good for a high-sugar diet here.

What Does The Evidence Say?

Though I’ve already covered quite a bit of the scientific evidence, one of the most alarming studies occurred in 2013, in The New England Journal Of Medicine, which found that higher glucose levels may be a risk factor for dementia—even among people without diabetes. This means that you would never know that you were at increased risk for Alzheimer’s. In fact, you may think that you are perfectly healthy. Another recent study confirmed the glucose issue, stating that insulin resistance is associated with significantly lower cerebral glucose metabolism.

If one needs more evidence, a 2013 study summed up the overall situation with obesity, type 2 diabetes, and Alzheimer’s. The author of this study stated that: “the incidence of type 2 diabetes has increased dramatically over the last decades mainly due to Western lifestyle factors such as lack of exercise and high calorie diets.”

 A 2013 study in The New England Journal Of Medicine found that higher glucose levels may be a risk factor for dementia—even among people without diabetes.

Since exercising can increase the size of your hippocampus, it makes sense that exercising less would cause it to shrink. In fact, this was actually proven. But let’s go back to the 2013 study where the author was laying out why Alzheimer’s is clearly related to sugar. He goes on to state in his conclusion that: “High-sugar diets are thought to promote weight gain and insulin resistance predisposing to type 2 diabetes. To aggravate this scenario, it has been consistently shown that type 2 diabetes is a risk factor for Alzheimer’s disease and both disorders share similar demographic profiles, risk factors, and clinical and biochemical features (e.g. insulin resistance).”

This is pretty definitive proof that the risk for Alzheimer’s goes way up if consuming a diet rich in sugar. Remember—The New England Journal Of Medicine study proved that one need not even be diabetic, in order to be at an increased risk for Alzheimer’s. In fact, one of the best preventative measures for developing Alzheimer’s is switching to a low-sugar diet, like a Paleo approach. This is why Dr. Perlmutter, in Grain Brain, recommends adopting a ketogenic diet for long-term brain health.

The Bottom Line

There are plenty of reasons to avoid sugar. However, the neurological risk seems to be the best reason. Since we still don’t completely understand Alzheimer’s disease, and because the symptoms are so crippling, it makes sense to take every possible precaution to avoid the disease. By the time I reach old age, I believe the science on this will be conclusive, as we are currently seeing the low-fat guidelines—once thought to be the final word—being lifted.

The only problem really lies within industry and politics, as companies like Coca-Cola spend a staggering amount of money on getting us to consume astounding amounts of sugar. If it becomes well-known that sugar can cause brain damage…well, the economic implications are obvious. I hope you’ve found this piece informative, as this health issue applies to everyone. Whether or not you are genetically at risk for Alzheimer’s, take precautions to avoid developing it. Cutting out the sugar should be step one.