Key Dietary Strategies to Protect Yourself from Alzheimer’s

Story at-a-glance

  • Your diet has major implications for your Alzheimer’s risk. Diets high in carbohydrates, and diets low in healthful fats, lead to Alzheimer’s disease
  • Research from the Mayo Clinic shows that diets rich in carbohydrates are associated with an 89 percent increased risk for dementia. Meanwhile, high-fat diets are associated with a 44 percent reduced risk
  • Alzheimer’s is directly related to chronically elevated blood sugar levels
  • Women given cholesterol-lowering statin medication have a 44 percent increased risk for becoming a type 2 diabetic. Diabetes, in turn, doubles your risk for Alzheimer’s disease
  • Even if you’re already having “senior moments,” you can regenerate cells in your brain’s memory center. This occurs through a process called neurogenesis. Proper lifestyle choices are imperative for this recovery


This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.

By Dr. Mercola

Alzheimer's disease has become nothing short of epidemic in the US. Could it be that some commonly eaten foods are the primary culprit? According to neurologist Dr. David Perlmutter, author of the book Grain Brain, your diet has major implications for your Alzheimer's risk.

Grain Brain has been on the New York Times Best Seller list for six months now, which is unusual for a health book. He has also been on a few PBS specials. Dr. Perlmutter is also the editor-in-chief of a brand new Harvard-based journal called Brain and Gut, slated to come out next year.

He came to the conclusion that brain dysfunction is rooted in a flawed diet, particularly our modern-day high-grain diet, after scouring the medical literature looking for clues to the underlying cause.

He'd grown weary of treating his patients' symptoms, and wanted to get to the bottom of the problem. As it turns out, the scientific literature is actually replete with information telling us that, yes, diet plays a crucial role in brain function. He says:

"What we've crystallized it down to now, in essence, is that diets that are high in sugar and carbohydrates, and similarly diets that are low in fat, are devastating to the brain.

When you have a diet that has carbohydrates in it, you are paving the way for Alzheimer's disease. I want to be super clear about that. Dietary carbohydrates lead to Alzheimer's disease.It's a pretty profound statement, but it's empowering nonetheless when we realize that we control our diet. We control our choices, whether to favor fat or carbohydrates."

High-Carb Diets Associated with 89 Percent Increased Risk for Dementia

As just one example, he cites research from the Mayo Clinic, published in the Journal of Alzheimer's Disease, which found that diets rich in carbohydrates are associated with an 89 percent increased risk for dementia. Meanwhile, high-fat diets are associated with a 44 percent reduced risk.

Clearly, with Alzheimer's disease now hot in the tracks behind heart disease and cancer as one of the top three killers in the US, we really need to pay attention to such findings.

"[T]here is absolutely no treatment for Alzheimer's disease. And yet, according to Dr. Deborah Barnes, publishing in the journal Lancet Neurology, more than half the cases of Alzheimer's disease today – 54 percent – could have been prevented had people gotten this information," he says.

Fortunately, even if you're already having "senior moments," you can turn back the clock, as it were. You can regenerate cells in your brain's memory center. This occurs through a process called neurogenesis.

According to Dr. Perlmutter, the evidence clearly shows that high-carb diets and elevation of blood sugar is directly related to shrinkage of your brain's memory center. And when your hippocampus—your memory center—shrinks, your memory declines.

"That is the harbinger for Alzheimer's disease," Dr. Perlmutter says. "It's the first place you look on a brain scan. But here is why we're having this conversation today: (1) it is preventable and (2) more importantly, it's reversible."

Saturated Fats Are a Critical Part of a Heart- and Brain-Healthy Diet

Like myself, Dr. Perlmutter has been talking about the benefits of saturated fat for a long time. Conversely, for well over half a century, the media and a majority of health care officials have warned that saturated fats are bad for your health and lead to a host of negative consequences, including high cholesterol, obesity, and heart disease.

There's little doubt that this wholly inappropriate fat phobia has had a lot to do with our burgeoning Alzheimer's epidemic. Fortunately, the importance of these healthy fats is starting to become more widely recognized. One of the largest meta-analyses1, 2, 3 to date, included data from more than 600,000 people from 18 countries.

The study concluded that current evidence does NOT support guidelines that encourage low consumption of saturated fat for heart health. Saturated fats, which have the longest history of being (wrongfully) demonized, were in fact found to have NO adverse effect on heart disease risk.

"We've been led down the wrong road," Dr. Perlmutter says. "[Saturated] fat is your friend. You desperately need fat. You desperately need to have good cholesterol in your body. That war on cholesterol is a perversion of the science that was even used to tell us we should stop eating foods with cholesterol...

We know quite well that in elderly individuals, for example, those in the highest level of blood cholesterol have about a 70 percent risk reduction for becoming demented. These are the things that are good for the heart. They're good for the immune system. Cholesterol is the precursor of vitamin D, progesterone, estrogen, testosterone, and cortisol...This is probably one of the reasons why statin drugs are so damaging. You lower cholesterol, and you set the stage for things that are very, very worrisome."

Diabetes Doubles Your Risk of Alzheimer's

Dr. Perlmutter cites a study published in the Archives of Internal Medicine, which found that women who are given cholesterol-lowering statin medication have a 44 percent increased risk for becoming a type 2 diabetic. Diabetes, in turn, doubles your risk for Alzheimer's disease.

Our ancestral diet was very high in saturated fats and virtually void of non-vegetable carbohydrates. Today, not only do we eat tremendous amounts of carbohydrates, these carbs are refined and highly processed. In the last decade, we've also shifted over to genetically engineered grains and sugar (GMO sugar beets and corn).

At present, you have close to a 50/50 chance of developing Alzheimer's disease if you live to be 85 years old, according to Dr. Perlmutter. His mission is to radically shift those odds, by giving people like yourself the information you need to avoid being one of the unlucky ones destined to die without your mental faculties intact.

Alzheimer's Is Directly Related to Elevated Blood Sugar Levels

A study published in the New England Journal of Medicine in August 2013 demonstrates that even mild elevation of blood sugar—a level of around 105 or 110—was already dramatically associated with an elevated risk for becoming demented. Dr. Perlmutter believes it's very important for physicians to become cognizant of this link, and to stop downplaying the risks associated with even mildly elevated blood sugar.

If your fasting blood sugar is even mildly elevated (over 95 mg/dl), it's time to address your diet to lower it. Dr. Perlmutter makes a very important point here, noting that "normal" blood sugar really should not be the same as the average. It should be the optimal or ideal level. You do not want to be right smack in the middle "average" when the population sample is severely diseased!

So what is an ideal fasting blood sugar level? Dr. Perlmutter suggests that anything over 92 or 93 is too high. He believes the ideal fasting blood sugar level is around 70-85, with 95 as the maximum. If you're fat adapted, there's no reason to shun even lower fasting blood sugar levels. According to Dr. Perlmutter:

"It really depends on whether you have adapted your body to burning fat. People who have been on a high-fat, low-carb diet are able to tap into body fat as an energy resource. They've undergone a change called keto-adaptation. It means they're burning fat and they can get by with much lower blood sugar because they're burning fat and don't need to worry about blood sugar as much.

This notion that your brain needs sugar is really old news as well. Fat, specifically ketones, which your body produces by metabolizing your fat, is now called a 'brain superfuel.' There is even a pharmaceutical product; a medical food that you can write as a prescription, which raises the level of ketones or fat in the bloodstream of patients, offered up now as a treatment for Alzheimer's disease. Who knew? The point is the brain loves to burn fat. That's what we have to shift it over to..."

Intermittent Fasting Can 'Reset' Your Body to Burn Fat Again

One of the tools I've found particularly useful is intermittent fasting, which can really help jumpstart your body into burning fat instead of carbs as its primary fuel. In his book, Grain Brain, Dr. Perlmutter also starts off the intervention section with a period of fasting, which can be viewed as pressing the Reset button. He's particularly aggressive about it in patients who are insulin/leptin resistant. 

I typically recommend keeping your fasting insulin level below 3. The so-called normal, however, is anywhere from 5-25 microU per mL. This despite the fact that the upper edge of this "normal" clearly indicates you have a problem with insulin resistance! Again, you do not want to be average here. You want your insulin/leptin levels to be ideal or optimal for health and disease prevention.

"If somebody has an insulin level of 26, they are in deep dudu. They need a lot of work. They need to fast. They need to drop the carbs. They need to add back the good fat. They need to add in some anti-glycating agents like benfotiamine and resveratrol. We need to hit these people aggressively. This is what works. This is what reduces their risk of converting to diabetes, and therefore has a huge role to play in protecting their brains," Dr. Perlmutter says.

Eat the Right Types of Fat, and Remember That Food Is Information

The type of fat you eat naturally makes all the difference in the world. Avoid all trans fats or hydrogenated fats that have been modified in such a way to extend their longevity on the grocery store shelf. This includes margarine, vegetable oils, and various butter-like spreads. Sources of healthy fats to add to your diet include:


Butter made from raw, grass-fed organic milk

Raw dairy

Organic pastured egg yolks

Coconuts and coconut oil (coconut oil actually shows promise as an effective Alzheimer's treatment in and of itself)

Unheated organic nut oils

Raw nuts, such as pecans and macadamia, which are low in protein and high in healthy fats

Grass-fed meats


"Let me make one other important point. Fat, protein, and carbohydrates are the Big Three in terms of food. That said, we've got to understand two things: (1) the human requirement for carbohydrates is zero. We require no carbohydrates in the diet, unlike fat and protein. (2) Well beyond the sources of calories that we take in, food is information. The foods that we choose to consume are instructing our DNA in terms of its expression. This is called epigenetics. How empowering is that?

I make this point because our genome takes 50,000 to 70,000 years to make significant changes to adapt to new environments and adapt to new foods. We are instructing our genome with this perverted information by giving our genomes signals from high levels of processed foods and carbohydrates. To me, job one is to get people to understand that you are affecting your gene expression and giving it bad information. This is a cornerstone in terms of almost every health malady that we are trying to deal with today," he says.

Exercise Promotes Neurogenesis

Beyond its ability to burn calories and fat, aerobic exercise is a powerful epigenetic player. It can help alter your gene expression to code for things that will result in a longer and healthier life. Exercise also reduces free radical production and inflammation, both of which are drivers for chronic disease. More directly, exercise has been shown to turn on a brain growth hormone called BDNF, which stands for "brain-derived neurotrophic factor." BDNF codes for your brain's ability to both repair itself and grow new brain cells. The latter occurs through a process known as neurogenesis.

This is indeed new information. Back when Dr. Perlmutter and I were in medical school, we were taught that once a brain cell dies, that's it; there's no going back. This view has been completely demolished by more recent research, which clearly demonstrates that your brain can both regrow neurons and even rewire itself to "work around" damaged areas. As for the type of exercise, Dr. Perlmutter recommends high-intensity interval training (HIIT), which provides you with the equivalent of two hours-worth of conventional aerobic exercise in just 20 minutes.

Other Recommendations That Promote Brain Health

Dr. Perlmutter's Grain Brain program also includes a number of other recommendations, including but not limited to:

Turmeric, for its anti-inflammatory potential and ability to activate BDNF, the hormone involved in brain health and neurogenesis.

Monitoring your vitamin D level. Dr. Perlmutter recommends maintaining an optimal level of around 70-90 nanograms per milliliter (ng/ml) year-round.

Optimizing your gut health by reseeding your gut with beneficial bacteria (probiotics). One recent study cited by Dr. Perlmutter correlates the risk for becoming an Alzheimer's sufferer in various countries; countries that have a lot of parasites in the gut as a marker of poor hygiene actually had the lowest risk of Alzheimer's. Countries where there were no parasites in the gut or very few, courtesy of superior hygiene, had a significantly higher risk of Alzheimer's.

"Who knew? Who knew that eating foods that have a little dirt on them can be good, and that delivering our children through the birth canal is so important for building their microbiome from day one? We've got a lot to learn," he says.

Equally important as adding probiotics is avoiding antibiotics. Non-breastfed babies are more prone to ear infections, which can easily set them up for excessive antibiotic use—even though antibiotics typically do not work for ear infections... So please, do your homework before demanding antibiotics. Eating CAFO meats will also provide you with traces of antibiotics in each bite. All these antibiotics kill beneficial bacteria, and the resulting chronic poor gut health can place your brain at significant risk.

Measuring your gluten sensitivity with a Cyrex [Array 3] test. Research suggests gluten can play a damaging role by the changes it imparts on your microbiome, the bacteria in your gut. But gluten can also wreak havoc with your neurological health via the inflammation it causes. Non-celiac gluten sensitivity may involve 30 to 40 percent of the population, Dr. Perlmutter says, and according to work done at Harvard by Dr. Alessio Fasano, it may even affect every single human being.

The reason for this is because gluten, a protein found in wheat, barley, and rye, has significant effects on your gut cells, which leads to the production of a chemical called zonulin. Zonulin enhances inflammation and tends to make your gut porous and leaky (i.e. leaky gut syndrome). But that's not all. Dr. Fasano discovered that it can also make your blood-brain barrier leaky, allowing foreign proteins to migrate into your brain, where they clearly do not belong.

Fecal transplantation, in cases of severe neurological dysfunction where poor gut flora appears to be a contributing factor. Your microbiome is critical for multiple reasons, including regulating the set point of inflammation, producing neurotransmitters like serotonin, and modulating systems associated with brain function and brain health. This form of therapy is now the standard of care for life-threatening C. difficile infections.

A Brain Healthy Diet Will Benefit All Neurological Disorders

It's worth noting that a high-fat, low-carb ketogenic diet is not just for the treatment of Alzheimer's and other forms of dementia. It's the right diet for ALL brain-related disorders, including but not limited to:

  • Parkinson's disease (according to Dr. Perlmutter, the rate at which a Parkinson's patient will decline perfectly correlates with the elevation of their blood sugar)
  • Migraines
  • Seizure disorders like epilepsy
  • Autoimmune disorders like multiple sclerosis (MS)
  • Attention deficit hyperactivity disorder (ADHD)

Core Ingredients of a Brain-Healthy Diet

In terms of a brain-healthy diet, Dr. Perlmutter emphasizes the importance of favoring above-ground colorful vegetables, as these contain less starch, which your body breaks down into simple sugars. Healthful options include kale, chard, collards, broccoli, and spinach. These also contain plenty of healthy fiber—you really do not need grains to meet your fiber requirement.

Dr. Perlmutter also recommends cooking your food as little as possible. The more food you can eat raw, the better, especially as it relates to your microbiome. To this, I would add fermented vegetables, to promote healthy bacteria in your gut, and sprouted seeds, for a boost of nutrients that is hard to match. Sprouts are also really easy to grow at home, which is an added boon for anyone seeking to improve their nutrition for the least amount of money. As for animal protein:

"I think that if you choose to be a meat-eater, you should be choosing meats that are grass-fed and that are organically raised. There's no alchemy that happens when cattle are given genetically modified grain, treated with antibiotics and hormones, and who knows what else. There's no alchemy that happens to create this wonderful meat. You've got to be super selective," he warns.

"Meat, by and large, is a dangerous food with the exception, in my opinion, of those grass-fed products – wild fish as opposed to farm-raised, antibiotic-treated Frankenfish, pasture-raised chicken, and farm-raised or pasture-raised eggs as well. We look at foods in terms of how they're going to treat us with respect to inflammation, and we know that, for example, factory farm-raised eggs are about 14 times as high in omega-6 fatty acids, the pro-inflammatory fatty acids, as compared to natural, pasture-raised, free-range eggs."

Take Control of Your Brain Health—For Life

In closing, Dr. Perlmutter quotes the Yellow Emperor of 4th century B.C. who said: "Maintaining order rather than correcting disorder is the ultimate principle of wisdom. To cure disease after it has appeared is like digging a well when one feels thirsty or forging weapons after the war has already begun." Your lifestyle choices have a huge role to play in determining whether your brain will maintain its function throughout your lifetime, or degenerate with age into a potentially deadly neurological disease like Alzheimer's. Again, the key lifestyle factors that will promote lifelong brain health are:

  • Eating a whole food, low- or no-carb, high-fat diet; ideally organic with a focus on raw foods. Your main source of carbohydrates would be above-ground vegetables, which are low in starch and high in beneficial fiber. Every effort should be made to keep your fasting blood sugar level at or below 85, and your fasting insulin level below 3. Avoiding carbohydrates (think processed foods, refined sugars, processed fructose, and all grains) along with exercise are the right tools for this.
  • Intermittent fasting can help "reset" your body, jumpstarting its ability to use fat as its primary fuel.
  • Maintaining a healthy gut flora by regularly eating fermented foods (and/or a probiotic supplement), and avoiding all medically unnecessary sources of antibiotics. This includes antibiotic treatments for viral infections (which do not respond to antibiotics) or minor infections that can be treated with other natural alternatives, and eating animal products (meat, dairy, and eggs) raised in confined animal feeding operations (CAFOs) as these are fed low doses of antibiotics for growth-promoting purposes.
  • Optimizing your vitamin D levels, ideally through appropriate sun exposure or by using a safe tanning bed. A vitamin D3 supplement can be used if neither of those options is feasible. Just remember that if you take supplemental vitamin D, you also increase your body's need for vitamin K2.


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