By Dr. Mercola
The cause of the debilitating, and fatal, brain disease Alzheimer's is conventionally said to be a mystery.
While we know that certain diseases, like type 2 diabetes, are definitively connected to the foods you eat, Alzheimer's is generally thought to strike without warning or reason.
That is, until recently.
Now, a growing body of research suggests there may be a powerful connection between the foods you eat and your risk of Alzheimer's disease and dementia, via similar pathways that cause type 2 diabetes.
Some have even re-named Alzheimer's as "type 3 diabetes."
Can You Eat Your Way to Alzheimer's?
In a recent animal study, researchers from Brown University in Providence, Rhode Island were able to induce many of the characteristic brain changes seen with Alzheimer's disease (disorientation, confusion, inability to learn and remember) by interfering with insulin signaling in their brains.1
Faulty insulin (and leptin, another hormone) signaling is an underlying cause of insulin resistance, which, of course, typically leads to type 2 diabetes. However, while insulin is usually associated with its role in keeping your blood sugar levels in a healthy range, it also plays a role in brain signaling. When researchers disrupted the proper signaling of insulin in the brain, it resulted in dementia.
What does this have to do with your diet?
Everything, as over-consumption of sugars and grains is what ultimately causes your body to be incapable of "hearing" the proper signals from insulin and leptin, leaving you insulin resistant in both body and brain.
Alzheimer's disease was tentatively dubbed "type 3 diabetes" in early 2005 when researchers learned that the pancreas is not the only organ that produces insulin. Your brain also produces insulin, and this brain insulin is necessary for the survival of your brain cells.
If You Have Diabetes, Your Risk of Alzheimer's Increases Dramatically
Diabetes is linked to a 65 percent increased risk of developing Alzheimer's,2 which may be due, in part, because insulin resistance and/or diabetes appear to accelerate the development of plaque in your brain, which is a hallmark of Alzheimer's.3 Separate research has found that impaired insulin response was associated with a 30 percent higher risk of Alzheimer's disease,4 and overall dementia and cognitive risks were associated with high fasting serum insulin, insulin resistance, impaired insulin secretion and glucose intolerance.
A drop in insulin production in your brain may contribute to the degeneration of your brain cells, mainly by depriving them of glucose, and studies have found that people with lower levels of insulin and insulin receptors in their brain often have Alzheimer's disease (people with type 2 diabetes often wind up with low levels of insulin in their brains as well). As explained in New Scientist, which highlighted this latest research:5
"This new focus [on the Alzheimer's/diabetes/insulin connection] follows a growing recognition of insulin's role in the brain. Until recently, the hormone was typecast as a regulator of blood sugar, giving the cue for muscles, liver and fat cells to extract sugar from the blood and either use it for energy or store it as fat. We now know that it is a master multitasker: it helps neurons, particularly in the hippocampus and frontal lobe, take up glucose for energy, and it also regulates neurotransmitters, like acetylcholine, which are crucial for memory and learning.
What's more, it encourages plasticity – the process through which neurons change shape, make new connections and strengthen others. And it is important for the function and growth of blood vessels, which supply the brain with oxygen and glucose.
As a result, reducing the level of insulin in the brain can immediately impair cognition. Spatial memory, in particular, seems to suffer when you block insulin uptake in the hippocampus… Conversely, a boost of insulin seems to improve its functioning.
...this role in the brain 'makes evolutionary sense,' since it would help us to remember the location of a food source. As our ancestors gorged on berries in the savannah, for instance, the spike in glucose and the subsequent rush of insulin would signal 'remember this, it's important,' causing the brain to crystallise the memory.
But as we know from type 2 diabetes, processes that evolved to help us meet the challenges of prehistory can easily backfire in the modern world.
When people frequently gorge on fatty, sugary food, their insulin spikes repeatedly until it sticks at a higher level. Muscle, liver and fat cells then stop responding to the hormone, meaning they don't mop up glucose and fat in the blood. As a result, the pancreas desperately works overtime to make more insulin to control the glucose – and levels of the two molecules skyrocket.
...The pancreas can't keep up with the demand indefinitely, however, and as time passes people with type 2 diabetes often end up with abnormally low levels of insulin."
Alzheimer's Might be "Brain Diabetes"
It's becoming increasingly clear that the same pathological process that leads to insulin resistance and type 2 diabetes may also hold true for your brain. As you over-indulge on sugar and grains, your brain becomes overwhelmed by the consistently high levels of insulin and eventually shuts down its insulin signaling, leading to impairments in your thinking and memory abilities, and eventually causing permanent brain damage.
You may already know I have become passionate about warning of the dangers of fructose. There is NO question in my mind that regularly consuming more than 25 grams of fructose per day will dramatically increase your risk of dementia and Alzheimer's disease. Consuming too much fructose will inevitably wreak havoc on your body's ability to regulate proper insulin levels.
Although fructose is relatively "low glycemic" on the front end, it reduces the affinity for insulin for its receptor leading to chronic insulin resistance and elevated blood sugar on the back end. So, while you may not notice a steep increase in blood sugar immediately following fructose consumption, it is likely changing your entire endocrine system's ability to function properly behind the scenes.
Additionally, fructose has other modes of neurotoxicity, including causing damage to the circulatory system upon which the health of your nervous system depends, as well as profoundly changing your brain's craving mechanism, often resulting in excessive hunger and subsequent consumption of additional empty carbohydrate-based calories.
In one study from UCLA, researchers found that rats fed a fructose-rich and omega-3 fat deficient diet (similar to what is consumed by many Americans) developed both insulin resistance and impaired brain function in just six weeks.6
Plus, when your liver is busy processing fructose (which your liver turns into fat), it severely hampers its ability to make cholesterol, an essential building block of your brain crucial to its health. This is yet another important facet that explains how and why excessive fructose consumption is so detrimental to your health.
Since the average American is exceeding this recommendation by 300% this is a pervasive and serious issue. I view significantly reducing fructose consumption as the MOST important step you can take to lower your risk of Alzheimer's disease.
More Tips for Avoiding Alzheimer's Disease
The beauty of following my newly revised Nutrition Plan is that it helps treat and prevent all chronic degenerative diseases, from the common ones like heart disease, cancer, diabetes, obesity and Alzheimer's to the ones you have never heard of or can't even pronounce. So please read the Plan as soon as you can. It is divided into three helpful sections, Beginner, Intermediate and Advanced to help you start at the right level.
The plan is the first step in addressing Alzheimer's disease, which is currently at epidemic proportions, with 5.4 million Americans – including one in eight people aged 65 and over – living with the disease.7 By 2050, this is expected to jump to 16 million, and in the next 20 years it is projected that Alzheimer's will affect one in four Americans.
In spite of how common memory loss is among Westerners, it is NOT a "normal" part of aging. While even mild "senior moments" may be caused by the same brain lesions associated with Alzheimer's disease and other forms of dementia, these cognitive changes are by no means inevitable! People who experience very little decline in their cognitive function up until their deaths have been found (post-mortem) to be free of brain lesions, showing that it's entirely possible to prevent the damage from occurring in the first place… and one of the best ways to do this is by leading a healthy lifestyle.
- Fructose. As mentioned, most everyone will benefit from keeping their total fructose consumed to below 25 grams per day.
- Improve Magnesium Levels. There is some exciting preliminary research strongly suggesting a decrease in Alzheimer symptoms with increased levels of magnesium in the brain. Unfortunately most magnesium supplements do not pass the blood brain levels, but a new one, magnesium threonate, appears to and holds some promise for the future for treating this condition.
- 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.8 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 is imperative for proper functioning of your immune system to combat inflammation that is also associated with Alzheimer's.
- Keep your fasting insulin levels below 3. This is indirectly related to fructose, as it will clearly lead to insulin resistance. However other sugars (sucrose is 50% fructose by weight), grains and lack of exercise are also important factors.
- Vitamin B12: According to a small Finnish study recently published in the journal Neurology,9 people who consume foods rich in B12 may reduce their risk of Alzheimer's in their later years. For each unit increase in the marker of vitamin B12 (holotranscobalamin) the risk of developing Alzheimer's was reduced by 2 percent. Very high doses of B vitamins have also been found to treat Alzheimer's disease and reduce memory loss.
- Eat a nutritious diet, rich in folate, such as the one described in my nutrition plan. Vegetables, without question, are your best form of folate, and we should all eat plenty of fresh raw veggies every day.
- High-quality animal-based omega-3 fats, such as krill oil. (I recommend avoiding most fish because, although fish is naturally high in omega-3, most fish are now severely contaminated with mercury.) 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.
- Avoid and remove mercury from your body. Dental amalgam fillings, which are 50% 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 aluminum, such as antiperspirants, non-stick cookware, vaccine adjuvants, etc.
- Exercise regularly. It's been suggested that exercise can trigger a change in the way the amyloid precursor protein is metabolized,10 thus, slowing down the onset and progression of Alzheimer's. Exercise also increases levels of the protein PGC-1alpha. Research has also shown that people with Alzheimer's have less PGC-1alpha in their brains11 and cells that contain more of the protein produce less of the toxic amyloid protein associated with Alzheimer's. I would strongly recommend reviewing the Peak Fitness Technique for my specific recommendations.
- Avoid flu vaccinations as most contain both mercury and aluminum, well-known neurotoxic and immunotoxic agents.
- Eat plenty of blueberries. Wild blueberries, which have high anthocyanin and antioxidant content, are known to guard against Alzheimer's and other neurological diseases.
- 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.
- Avoid anticholinergic 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.