They call it type 3 diabetes — with good reason.
Over 80% of people with Alzheimer’s disease have either type 2 diabetes or abnormal blood sugar levels. So close is the link between the two conditions that scientists have taken to referring to Alzheimer’s as “type 3 diabetes”.
The evidence linking Alzheimer’s to diabetes is compelling, and centres on insulin. Insulin is a hormone secreted and released by the pancreas when food is eaten, primarily carbohydrates.
Carbohydrates are broken down in the gut into units of glucose before entering the blood. That is how blood sugar is raised.
Blood sugar levels must be tightly regulated. Too much, or too little, are both potentially dangerous situations. The more glucose in the blood, the more the pancreas produces insulin to lower that glucose.
Insulin resistance: when blood sugar goes awry.
And this is where it can all start to go wrong.
The human body wasn’t designed to cope with a regular deluge of sugar. It can only deal with so much before it develops signs of not coping with its workload.
Insulin resistance is one such sign. It is described as a “pre-diabetic” condition that arises when insulin metabolism goes wrong. Basically, it means that insulin has started to lose its effect, and glucose remains in the blood instead of being processed normally.
The body, sensing that there is still too much sugar in the blood, pumps out even more insulin in an effort to deal with it, but to little or no effect. If this keeps up for long enough, insulin resistance leads to diabetes.
The reason for the development of insulin resistance is quite simple. A relentless diet of sugary foods and drinks, refined carbohydrates (bread, rice, chips, cakes, biscuits, confectionery and so on) eventually takes its toll.
This extreme form of diet is not natural, yet it has somehow come to be regarded as normal.
From type 2 to type 3 diabetes
How does this link to Alzheimer’s disease? High insulin levels can interfere with neurons and affect cognitive function, including memory and concentration. Greater exposure to glucose also means increased susceptibility to a process known as glycation.
Glycation is the link between diabetes and Alzheimer’s. It is a process whereby certain proteins become damaged when exposed to high levels of glucose. This glycation process creates proteins known as advanced glycation end-products (AGEs).
These AGEs can prevent neurons from working properly. Research has found that the brains of people with Alzheimer’s disease have high levels of these AGEs, compared to people without the disease. AGEs contribute to the formation of amyloid plaques — a characteristic of the brains of people with Alzheimer’s.
In short, an endless diet of sugary food and refined carbohydrates gives rise to insulin resistance, which can ultimately give rise to type 2 diabetes and later Alzheimer’s.
We’ve known this since the 1990s when the literature began to emerge, but it is only just starting to trickle through now. The term “type 3 diabetes” was first coined by researchers writing in the Journal of Alzheimer’s Disease in 2005. Critical mass was achieved when New Scientist magazine featured the topic on the cover of the 1 September 2012 issue.
The ketogenic diet, Alzheimer’s and type 3 diabetes
The link between blood sugar and dementia may sound alarming, but it offers enormous hope. That’s because type 2 diabetes is a lifestyle disease, and therefore largely avoidable.
With appropriate dietary changes you can reduce your chances of developing type 2 diabetes — and simultaneously reduce your chances of developing type 3 diabetes.
You may have heard of the ketogenic diet. It was originally (and still is) used to treat people with epilepsy. Indeed, it is considered a “proven therapy for drug-resistant epilepsy”. There’s your clue — epilepsy is a brain disorder.
The diet works extremely well. Basically, it is a high fat, very low carbohydrate diet. By its nature, it greatly restricts the amount of insulin and therefore glucose in the blood. Without carbohydrates to burn as fuel, the body switches to producing something called ketone bodies, from fat.
It’s not just about epilepsy. The ketogenic — or low carbohydrate — diet has also been found to be therapeutic in the treatment of people with mild cognitive impairment (MCI).MCI is a pre-Alzheimer’s stage.
Scientists gave 23 eldery people either a high carbohydrate or low carbohydrate diet for six weeks. At the end of the study, those on the low carbohdyrate diet experienced improved verbal memory performance, together with reductions in weight and waist circumference.
How does the ketogenic diet work? There are two possible explanations for these encouraging results. First, the high level of fat in the diet repairs damage to brain cells. The ketones produced from fat provide an alternative fuel to the brain, in place of glucose.
The second possibility is that the absence of sugar and refined carbohydrates in the diet initiates the healing process, and prevents further damage.
Here’s the other great thing about the ketogenic diet. Ketones are made in the liver, either from the fat you eat or the fat you have stored. So when you switch to a very low carbohydrate diet, your body starts to burn its fat stores, and consequently you lose weight.
A ketogenic diet not only reduces insulin secretion and your risk of developing Alzheimer’s, it promotes weight loss. That’s a pretty good deal.
Keep it simple
If you are healthy, but just want to reduce your risk of developing both diabetes and Alzheimer’s in later life, you don’t need to follow the ketogenic diet strictly. Just cut out all those unnecessary, unhealthy carbohydrates, especially anything with added sugar, including soft drinks. Even the sugar-free variety, sweetened with artificial sweeteners, play havoc with your blood sugar.
No one needs sugar. No one needs cookies, cakes, candies, chips and soda. Your body just needs real, wholesome food. You need plenty of protein — meat, fish, eggs, cheese — and plenty of vegetables to go with that protein.
Human dietary requirements are surprisingly simple.
Something else you can do is avoid snacking between meals. Apart from being superflous to dietary requirements, snacking means that insulin production is constantly stimulated. By abstaining from snacking you give your pancreas a rest, and your body the chance to start burning fat for fuel.
Alzheimer’s is a complex disease and there are many potential causes. But with cases of both Alzheimer’s and type 2 diabetes rising simultaneously, and at an alarming rate, making dietary changes that control glucose and insulin secretion has got to be a no-brainer for anyone looking to maintain good health well into later life.