By Dr. Mercola
More than 5 million Americans have Alzheimer's disease, and the number is steadily increasing. Someone in the US develops the disease every 67 seconds, and by 2025 it's estimated that the number with Alzheimer's will increase 40 percent to more than 7 million.1
By 2050, the prevalence of Alzheimer's is expected to nearly triple, reaching 13.8 million people. In 2015, it's already the sixth leading cause of death, and it's one that has no known cure or proven way to slow its progression.
There are, however, several known risks factors, including many that you can control. One of them is your weight, and new research has once again tied excess weight to an increased risk of this devastating disease.
Excess Weight in Midlife May Bring on Symptoms of Alzheimer's Earlier
People who are overweight at age 50 are more likely to develop Alzheimer's disease sooner than those who are not. The study followed 1,400 people who took cognitive tests regularly for a period of 14 years.
Among the 142 who went on to develop Alzheimer's disease, those who were overweight or obese at midlife developed symptoms nearly seven months sooner than those of a healthy weight.
Further, the onset of symptoms moved up by 6.7 months for each unit increase in midlife body mass index (BMI). Those with a high BMI were also more likely to have greater amounts of amyloid proteins in their brain, which is linked to Alzheimer's.
Although BMI is a flawed measurement tool, the findings are likely sound because obese adults often have additional risk factors for Alzheimer's, including high blood pressure and diabetes. Obesity is also linked to chronic inflammation, which might make Alzheimer's worse, along with insulin resistance, another known risk factor for Alzheimer's.
It's not the first time weight has been linked to Alzheimer's, either. In 2008, research revealed that central obesity (or excess weight around your midsection) is linked with an increased risk of dementia.2
Previous research has also found a strong correlation between body mass index (BMI) and high levels of beta-amyloid, the protein that tends to accumulate in the brains of Alzheimer's patients, causing plaque buildup.3 It is believed that beta-amyloid destroys nerve cells, contributing to the cognitive and behavioral problems typical of the disease.
The Inflammation and Insulin Resistance Connection…
When you consider that two hallmarks of obesity are insulin/leptin resistance and chronic inflammation, you can begin to recognize that excess weight is fertile ground for a wide array of other ailments — many of which can cut your life significantly short.
Previous research has shown that fat tissue secretes an inflammatory factor called CXCL5 that is linked to insulin resistance and participates in the development of type 2 diabetes.4,5
When you're insulin resistant, your cells have become seriously impaired in their ability to respond to the insulin your body makes. At the heart of this problem is a diet too high in sugar (especially processed fructose).
While you can be insulin resistant and lean, obesity places far greater stress on your cells, which makes insulin resistance more probable. Insulin resistance is at the core of nearly every chronic degenerative disease and Alzheimer's disease is no exception.
According to one Japanese study, insulin resistance and/or diabetes appear to accelerate the development of plaque in your brain. The study monitored 135 people for 10 to 15 years, 16 percent of whom developed Alzheimer's disease before they died, and autopsy showed they all had plaque in their brains.6
However, 72 percent of those with insulin resistance also had plaque, as well as 62 percent of those who did not have insulin resistance yet had very high blood sugar levels.
The authors believe that insulin resistance speeds up the development of plaque, hence accelerating and increasing your risk of developing Alzheimer's as you age.
Insulin resistance, in turn, often leads to diabetes, and diabetics have an increased risk of developing Alzheimer's disease.
Alzheimer's disease was even tentatively dubbed "type 3 diabetes" in 2005, when researchers discovered that your brain produces insulin that is necessary for the survival of your brain cells.
They found that a toxic protein called ADDL removes insulin receptors from nerve cells, thereby rendering those neurons insulin resistant, and as ADDLs accumulate, your memory begins to deteriorate.
Impaired acute insulin response at midlife was also associated with an increased risk of Alzheimer's disease up to 35 years later, which suggests "a causal link between insulin metabolism and the pathogenesis" of Alzheimer's disease, according to research published in Neurology.7
A Healthy Diet May Help You Lower Your Risk of Alzheimer's
A growing body of research suggests there's a powerful connection between your diet and your risk of developing Alzheimer's disease, via similar pathways that cause type 2 diabetes. The right diet can also help you avoid carrying the excess weight linked to the disease as well.
According to Dr. David Perlmutter, author of the book Grain Brain, 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."
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.
Very Little Sugar and Plenty of Healthy Fats Support Brain Health
A combination of very little sugar and grain carbs, along with higher amounts of healthy fats, is KEY for addressing not only Alzheimer's but diabetes and heart disease as well.
This type of diet will also likely help you lose weight. All of these conditions are rooted in insulin and leptin resistance, and the dietary answer is identical for all of them.
Understanding this can make your life easier, as you don't need to memorize the dos and don'ts for each and every disease you seek to avoid. Instead, what you need to do is shift over to a mindset that is focused on optimizing health. Disease prevention then becomes a beneficial "side effect." According to Dr. Perlmutter:
"[Alzheimer's] is a preventable disease. It surprises me at my core that no one's talking about the fact that so many of these devastating neurological problems are, in fact, modifiable based upon lifestyle choices…
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."
In order to reverse the Alzheimer's trend, we simply must relearn how to eat for optimal health. Processed "convenience foods" are quite literally killing us, inducing diabetes, heart disease, cancer, and dementia. The beauty of following my optimized nutrition plan is that it helps prevent and treat virtually ALL chronic degenerative diseases, including diabetes, heart disease, and Alzheimer's. The sooner you begin, the better,
Exercise Works with Your Diet to Lower Alzheimer's Risk
A healthy diet and exercise are key not only for maintaining a healthy weight and lowering your risk of diabetes… but also for supporting your brain health. Exercise also leads to hippocampus growth and memory improvement,8 and it's been suggested that exercise can trigger a change in the way the amyloid precursor protein is metabolized, thus, slowing down the onset and progression of Alzheimer's.9
Exercise also increases levels of the protein PGC-1alpha. Research has shown that people with Alzheimer's have less PGC-1alpha in their brains and cells that contain more of the protein produce less of the toxic amyloid protein associated with Alzheimer's.10 Exercise even impacts tau tangles, which form when the protein tau collapses into twisted strands, which ends up killing brain cells. In one study, sedentary adults diagnosed with mild cognitive impairment were randomly divided into one of two groups.
Four times a week, the first group did supervised aerobic workouts while the other did stretching exercises. After six months, the aerobic exercise group had statistically significant reductions in tau levels compared with those who only did stretching. They also experienced improved attention, planning, and executive function, courtesy of improved blood flow in brain regions associated with memory and processing. According to co-author Laura Baker:11
"These findings are important because they strongly suggest a potent lifestyle intervention such as aerobic exercise can impact Alzheimer's-related changes in the brain. No currently approved medication can rival these effects." [Emphasis mine]
Other lifestyle factors, particularly stress relief and sun exposure, are also potent allies against all forms of dementia. Ideally, you'll want to carefully review the suggested guidelines below and take steps to incorporate as many of them as you can into your daily lifestyle.
Dietary Strategies to Help Prevent Alzheimer's
- Avoid sugar and refined fructose.Ideally, you'll want to keep your sugar levels to a minimum and your total fructose below 25 grams per day, or as low as 15 grams per day if you have insulin/leptin resistance or any related disorders.
- Avoid gluten and casein (primarily wheat and pasteurized dairy, but not dairy fat, such as butter). Research shows that your blood-brain barrier is negatively affected by gluten. Gluten also makes your gut more permeable, which allows proteins to get into your bloodstream, where they don't belong. That then sensitizes your immune system and promotes inflammation and autoimmunity, both of which play a role in the development of Alzheimer's.
- Optimize your gut flora by regularly eating fermented foods or taking a high-potency and high-quality probiotic supplement.
- Increase consumption of all healthy fats, including animal-based omega-3. Sources of healthy fat include avocados, butter made from raw grass-fed organic milk, organic pastured egg yolks, coconuts and coconut oil, raw nuts, raw dairy, grass-fed meats, and pasture-raised poultry. Also make sure you're getting enough animal-based omega-3 fats, such as krill oil. High intake of the omega-3 fats EPA and DHA help by preventing cell damage caused by Alzheimer's disease, thereby slowing down its progression, and lowering your risk of developing the disorder.
- Reduce your overall calorie consumption, and/or intermittently fast. Ketones are mobilized when you replace carbs with coconut oil and other sources of healthy fats. Intermittent fasting is a powerful tool to jumpstart your body into remembering how to burn fat and repair the inulin/leptin resistance that is a primary contributing factor for Alzheimer's.
- Improve your magnesium levels. There is some exciting preliminary research strongly suggesting a decrease in Alzheimer's symptoms with increased levels of magnesium in the brain. Unfortunately, most magnesium supplements do not pass the blood-brain barrier, but a new one, magnesium threonate, appears to and holds some promise for the future for treating this condition and may be superior to other forms.
- Eat a nutritious diet rich in folate. Vegetables, without question, are your best form of folate, and we should all eat plenty of fresh raw veggies every day. Avoid supplements like folic acid, which is the inferior synthetic version of folate.
General Lifestyle Guidelines for Alzheimer's Prevention
Besides diet and exercise, there are a number of other lifestyle factors that can contribute to or hinder neurological health. The following strategies are therefore also important for any Alzheimer's prevention plan:
- Optimize your vitamin D levels with safe sun exposure. Strong links between low levels of vitamin D in Alzheimer's patients and poor outcomes on cognitive tests have been revealed. Researchers believe that optimal vitamin D levels may enhance the amount of important chemicals in your brain and protect brain cells by increasing the effectiveness of the glial cells in nursing damaged neurons back to health. Vitamin D may also exert some of its beneficial effects on Alzheimer's through its anti-inflammatory and immune-boosting properties.
Sufficient vitamin D (50 to 70 ng/ml) is imperative for proper functioning of your immune system to combat inflammation that is also associated with Alzheimer's.
- Avoid and eliminate mercury from your body. Dental amalgam fillings, which are 50 percent mercury by weight, are one of the major sources of heavy metal toxicity, however you should be healthy prior to having them removed. Once you have adjusted to following the diet described in my optimized nutrition plan, you can follow the mercury detox protocol and then find a biological dentist to have your amalgams removed.
- Avoid and eliminate aluminum from your body. Sources of aluminum include antiperspirants, non-stick cookware, vaccine adjuvants, and a surprising number of other products such as coffee creamers, cosmetics and beverage containers. For tips on how to detox aluminum, please see my article, "First Case Study to Show Direct Link between Alzheimer's and Aluminum Toxicity."
- Avoid flu vaccinations as most contain both mercury and aluminum, well-known neurotoxic and immunotoxic agents.
- Avoid anticholinergics and statin drugs. Drugs that block acetylcholine, a nervous system neurotransmitter, have been shown to increase your risk of dementia. These drugs include certain nighttime pain relievers, antihistamines, sleep aids, certain antidepressants, medications to control incontinence, and certain narcotic pain relievers.
Statin drugs are particularly problematic because they suppress the synthesis of cholesterol, deplete your brain of coenzyme Q10 and neurotransmitter precursors, and prevent adequate delivery of essential fatty acids and fat-soluble antioxidants to your brain by inhibiting the production of the indispensable carrier biomolecule known as low-density lipoprotein.
- Challenge your mind daily. Mental stimulation, especially learning something new, such as learning to play an instrument or a new language, is associated with a decreased risk of Alzheimer's. Researchers suspect that mental challenge helps to build up your brain, making it less susceptible to the lesions associated with Alzheimer's disease.