How Insulin Affects Alzheimer's + 2 Diets That May Lower The Risk
Alzheimer's disease is a form of dementia that most commonly affects aging adults. While there's no cure for the neurodegenerative disorder, there are proven preventive factors, including certain forms of exercise and diets. According to nutritional psychiatrist Georgia Ede, M.D., one of the most effective ways to reduce the risk of Alzheimer's is by lowering insulin levels.
In a mindbodygreen podcast episode, Ede says, "A lot of people don't realize that the path to Alzheimer's begins decades before the symptoms become obvious. And the path to Alzheimer's is paved with insulin resistance." Paying attention to this risk factor as early as 20 or 30 years old can help people pave different, healthier paths for aging.
What is insulin resistance?
Insulin is a master growth hormone made in the pancreas, Ede explains, and it controls the levels and activities of most other hormones in the body, including sex and stress hormones.
Insulin resistance occurs when cells in the fat, muscles, and liver can no longer respond to insulin and can't take glucose from the blood. To make up for it, the pancreas will pump out more insulin to help glucose enter the cells. Over time, this leads to blood sugar spikes.
How are insulin resistance and Alzheimer's related?
While insulin resistance is not the only determination of Alzheimer's, Ede says it is a very powerful risk factor. "The science is very clear," she says.
Research has shown insulin resistance directly affects the ability of the hippocampus1 (aka the brain's memory center) to access energy. Without proper energy levels, this region of the brain will begin to shrink and die, she explains, leading to cognitive and memory decline.
What eating styles help lower insulin levels?
Intermittent fasting (IF) can be healthy because the body spends less time in a food-processing mood and has more time to rest, rejuvenate, and heal, Ede explains.
Regardless of the type of diet someone's eating (keto, Mediterranean, paleo, vegan, etc.), IF has been shown to reduce both insulin and blood glucose levels2.
All that said, fasting can have its complications. For people with perfectionist tendencies, a history of trauma, or a need for attention, prolonged fasting can trigger competitive instincts, Ede says. It may not be the best option for people with a history of eating disorders.
Ketogenic (keto) diet
"A ketogenic diet is a therapeutic tool that I use in my practice every day," Ede says. In fact, she's seen patients with early Alzheimer's show improvements in mental clarity while following a keto diet.
Like IF, the keto diet helps lower and stabilize insulin levels and blood glucose levels3. "It allows your brain to burn more fat than glucose for energy," she adds.
When the body enters ketosis by creating ketones, those ketones along with glucose enter the brain. The mixture of the two, instead of glucose alone, helps the brain to run more efficiently, Ede says.
This encourages a growth factor in the brain (brain-derived neurotrophic factor) to grow new connections and remodel itself. "The level of that important growth factor goes up on a ketogenic diet without any supplementation," Ede says.
Insulin resistance has a major impact on brain health and memory function. Lowering insulin levels through diet early in life may be one way to lower the risk of Alzheimer's disease.
Both intermittent fasting and the keto diet have been shown to lower insulin and blood glucose levels, therefore benefiting brain health. Intermittent fasting poses greater psychological risks for certain people, while the keto diet has more scientifically proven brain health benefits, according to Ede.
Abby Moore is an editorial operations manager at mindbodygreen. She earned a B.A. in Journalism from The University of Texas at Austin and has previously written for Tribeza magazine. She has covered topics ranging from regenerative agriculture to celebrity entrepreneurship. Moore worked on the copywriting and marketing team at Siete Family Foods before moving to New York.