As Alzheimer’s disease (AD) rates continue to increase, researchers are desperately working to identify the causes of this destructive disease in order to find ways for better prevention. The list of possible causes currently being explored includes brain inflammation, hormonal factors, oxidative stress, environmental toxins, and even infection. Regardless of the specific cause, the resulting damage to the brain is demonstrated by two hallmark signs of AD: the presence of neurofibrillary tangles and amyloid plaque accumulation.
“Neurofibrillary tangles” are deformed fibers found inside the brain’s cells. Normally, tau protein helps stabilize microtubules which help transport nutrients throughout the nerves. But in AD, tau protein doesn’t stabilize the microtubules correctly and tangles form instead. This adversely affects nutrient transport.
“Beta amyloid” is a sticky protein fragment which in a healthy brain would naturally be eliminated. In AD, beta amyloid can amass and cause “plaques” in the brain. Amyloid plaque is thought to contribute to more inflammation in the brain and block proper brain cell communication.
Neurofibrillary tangles and beta amyloid are thought to be at least in part, a cause of damage to nerve cells and the loss of connections between nerve cells. This damage causes symptoms in the brain related to Alzheimer’s and dementia.
A recent study was published to better understand a possible cause of amyloid plaque accumulation. The research was focused on diet, particularly high glycemic diets, meaning a diet that consistently favors simple carbohydrates and sugar. The study began 4 years prior, and will continue longer while tracking the diets of adults who were considered cognitively healthy.
They found that in adults who consumed higher sugar and carbohydrates in their diets, there was an elevated level of cerebral amyloid present. In those with the highest sugar intake, specifically, they had worse cognitive performance in testing. At this stage of the study, there appears to be an association between a high glycemic diet and risk of developing AD.
Undoubtedly there are additional factors beyond diet that contribute to AD and they will all need to be addressed to effectively prevent it. Ultimately, this research may help solve an important piece of the puzzle, based on the connection we already know between inflammation and AD. A high sugar and simple carbohydrate diet can cause a spike in insulin from the pancreas, resulting in an increased production of free radicals and pro-inflammatory cytokines. Both contribute to increased inflammation throughout the body, but a diet consisting of less sugar and more protein can certainly help modify blood sugar and reduce this source of inflammation.
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Am J Clin Nutr. 2017 Dec;106(6):1463-1470. doi: 10.3945/ajcn.117.162263. Epub 2017 Oct 25.A high-glycemic diet is associated with cerebral amyloid burden in cognitively normal older adults. Matthew K Taylor