Category Archives: Dementia

June 29, 2013 · 5:08 PM

Upper Normal Blood Sugars Linked To Brain Shrinkage

MRI scan of brain

MRI scan of brain

Healthy bodies keep blood sugar levels in a fairly narrow range.  You might think you’re fine if you’re anywhere within the defined normal range.  Think again.  Australian researchers found that folks with fasting blood sugars toward the upper end of the normal range had more degeneration (atrophy) in parts of the brain called the hippocampus and amygdala, compared to those in the low normal range.  Degeneration in those areas is often manifested as dementia.

The hippocampus is critical for learning and memory formation and retention.  The amygdala is also involved in memory as well as emotion.  The two areas are intimately connected, literally.

How Was the Study Done?

Over 250 study participants aged 60 to 64 years had normal brains at baseline and were free of prediabetes and diabetes.  They were mostly caucasian.  MRI brain scans were done at baseline and again four years later.  Significant atrophy (shrinkage) was seen in the hippocampus and amygdala over time, with greater atrophy seen in those with higher baseline fasting glucose levels.

Fasting blood sugar was measured only once, at the start, and ranged from 58 to 108 mg/dl (3.2 to 6.0 mmol/l).  (Fasting glucose of 108 would be prediabetes according to the American Diabetes Association, but not by the World Health Organization.)  Participants weren’t tested for deterioration of cognition (actual thinking).

So What?

The results of the study at hand are consistent with others that link higher rates of dementia with diabetes.  Diabetics, even when under treatment, usually have higher average blood sugars than non-diabetics.  The study authors speculate that damage from higher blood sugars may be mediated by inflammation and abnormal blood clotting (prothrombotic factors and platelet activation).

The Mayo Clinic recently reported that diets high in carbohydrates and sugar increase the odds of developing cognitive impairment in the elderly years.

It’s interesting to contemplate whether non-diabetics and diabetics would have less risk of developing dementia if blood sugars could be kept in the lower end of the normal range.  How could you do that?  Possibilities include:

  • avoid sugars and other refined carbohydrates
  • limit all carbohydrates
  • favor low-glycemic-index foods over high
  • regular exercise, which helps maintain insulin sensitivity (insulin is a major blood sugar regulator)
  • avoid overweight and obesity, which helps maintain insulin sensitivity
  • for diabetics: all of the above plus drugs that control blood sugar

Steve Parker, M.D.

Reference:  Cherbuin, Nicolas, et al.  Higher normal fasting plasma glucose is associated with hippocampal atrophy: The PATH Study.  Neurology, September 4, 2012, vol. 79, No. 10, pp: 1,010-1,026.  doi:10.1212/WNL.0b013e31826846de

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April 6, 2013 · 2:00 AM

Which Diseases Do Vegetables and Fruits Prevent?

Potential answers are in the American Journal of Clinical Nutrition (2012).  I quote:

For hypertension, coronary heart disease, and stroke, there is convincing evidence that increasing the consumption of vegetables and fruit reduces the risk of disease. There is probable evidence that the risk of cancer in general is inversely associated with the consumption of vegetables and fruit. In addition, there is possible evidence that an increased consumption of vegetables and fruit may prevent body weight gain. As overweight is the most important risk factor for type 2 diabetes mellitus, an increased consumption of vegetables and fruit therefore might indirectly reduces the incidence of type 2 diabetes mellitus. Independent of overweight, there is probable evidence that there is no influence of increased consumption on the risk of type 2 diabetes mellitus. There is possible evidence that increasing the consumption of vegetables and fruit lowers the risk of certain eye diseases, dementia and the risk of osteoporosis. Likewise, current data on asthma, chronic obstructive pulmonary disease, and rheumatoid arthritis indicate that an increase in vegetable and fruit consumption may contribute to the prevention of these diseases. For inflammatory bowel disease, glaucoma, and diabetic retinopathy, there was insufficient evidence regarding an association with the consumption of vegetables and fruit.

It bothers me that vegetables and fruits are lumped together: they’re not the same.

All of my diets—Advanced Mediterranean, Low-Carb Mediterranean, and Ketogenic Mediterranean—provide plenty of fruits and vegetables.

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January 17, 2013 · 4:46 AM

Sugar and Carbohydrates Linked to Impaired Brain Function in Elderly

 

Note the sugar cubes

Note the sugar cubes

The Mayo Clinic recently reported that diets high in carbohydrates and sugar increase the odds of developing cognitive impairment in the elderly years.

Mild cognitive impairment is usually a precursor to dementia.  Many authorities think dementia develops more often in people with diabetes, although some studies refute the linkage.

Mayo investigators followed 940 patients with normal baseline cognitive functioning over the course of four years. Diet was assessed via questionnaire. Study participants were ages 70 to 89. As the years passed, 200 of them developed mild cognitive impairment.

Compared with those eating at the lowest level of carbohydrate consumption, those eating at the highest levels were almost twice as likely to go to develop mild cognitive impairment.

The scientists note that those eating lower on the carbohydrate continuum were eating more fats and proteins.  Whether the Low-Carb Mediterranean Diet prevents cognitive impairments remains to be seen.

Steve Parker, M.D.

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January 6, 2013 · 2:00 AM

Type 2 Diabetes Ages Brain Prematurely

Type 2 diabetes accelerates age-related cognitive decline in the Netherlands, according to new research published in Diabetes Care.  T2 diabetes is also linked to decreased brain gray matter in women.  Finally, T2 diabetes in the elderly is associated with altered brain structure (as seen on MRI scans) and impaired brain function.

The Mediterranean diet may help prevent this sort of decline.

—Steve

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April 19, 2012 · 6:53 AM

Right Diet Preserves Brain Function and Size

mp9004223691.jpg  Neurology last year reported that the proper diet seems to help prevent age-related brain shrinkage and cognitive decline.

From the press release:

People with diets high in several vitamins or in omega 3 fatty acids are less likely to have the brain shrinkage associated with Alzheimer’s disease than people whose diets are not high in those nutrients, according to a new study published in the December 28, 2011, online issue of Neurology, the medical journal of the American Academy of Neurology.

Those with diets high in omega 3 fatty acids and in vitamins C, D, E and the B vitamins also had higher scores on mental thinking tests than people with diets low in those nutrients. These omega 3 fatty acids and vitamin D are primarily found in fish. The B vitamins and antioxidants C and E are primarily found in fruits and vegetables.

So the dietary pattern linked to preservation of brain size and function in this study is: high omega-3 fatty acids and vitamins B, C, D, and E. I don’t know if study participants were getting these nutrients from supplements or from food or a combination. (I haven’t read the full article.)

Note that the time-honored Mediterranean diet is also associated with lower rates of dementia and slower rate of age-related mental decline.

I previously reported that a supplement cocktail of three B vitamins slowed the rate of brain shrinkage. 

Steve Parker, M.D.

Reference: Bowman, G.L., et al. Nutrient biomarker patterns, cognitive function, and MRI measures of brain aging. Neurology. doi: 10.1212/WNL.0b013e3182436598

h/t to Randall Parker at FuturePundit

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October 23, 2011 · 7:30 AM

Nasal Insulin Slows Dementia?

 

Insulin administered via the nasal passages slowed or stabilized mental functioning and functional abilities in a pilot study of people with Alzheimer disease and mild cognitive impairment, according to Seattle-based investigators.

As you probably know, dementia is a huge problem for our aging population, and Alzheimers is the most common form of dementia.  The Mediterranean diet is associated with lower risk of mild cognitive impairment and has long been linked to lower risk of dementia as well as slower mental decline in existing Alzheimer dementia patients.  The Mediterranean diet also seems to prolong life in Alzheimer patients.  So I’m always interested in ways to prevent and treat Alzheimers.  Mild cognitive impairment is often a precursor to Alzhiemer disease.

Methodology

The study involved 104 non-diabetic participants with Alzheimer disease (40) or amnestic mild cognitive impairment (64).  They were randomly assigned to one of three groups: placebo (control group), nasal insulin 20 IU twice daily, or nasal insulin 40 IU twice daily. 

Insulin was delivered through a ViaNase device which releases the insulin in to a chamber covering the nose; the participant breathes regularly for two minutes to pick up the dose.  This insulin goes directly to the central nervous system without affecting blood insulin levels or blood sugar levels.

Mental and functional abilities (for example, activities of daily living) were measured at baseline, then again 2, 4, and six months later.  Some of the participants (23) underwent lumbar puncture (for dementia biomarker analysis) and PET brain scans (18).

Comments

This was a well-designed pilot study.

Nasal insulin was well-tolerated.  It’s not commercially available in the U.S.

ResearchBlogging.orgRegarding the placebo group, I was surprised that the researchers could document mental and functional deterioration over this relatively short-term study (4–6 months).  I’m impressed with the need to treat age-related cognitive decline early and aggressively, when we have something that works.

How would nasal insulin work?  We don’t know for sure, but it seems to relate to insulin’s effect on

  • the ability of neurons (brain cells) to communicate with each other through synapses
  • modulaton of blood sugar metabolism in the hippocampus and other brain areas
  • facilitation of memory
  • ß-amyloid peptide

In case you’re wondering, standard subcutaneous injections of insulin can’t be used in studies like this because of the risk of low blood sugar.

I agree wholeheartedly with study authors that “these promising results provide an impetus for longer-term trials of intranasal insulin therapy in adults with amnestic mild cognitive impairment or Alzheimers disease.”

Psychiatrist Emily Deans blogged about this study at Evolutionary Psychiatry September 21, 2001.  Please see her cogent remarks.

Steve Parker, M.D.

Reference:  Craft, S., Baker, L., Montine, T., Minoshima, S., Watson, G., Claxton, A., Arbuckle, M., Callaghan, M., Tsai, E., Plymate, S., Green, P., Leverenz, J., Cross, D., & Gerton, B. (2011). Intranasal Insulin Therapy for Alzheimer Disease and Amnestic Mild Cognitive Impairment: A Pilot Clinical Trial Archives of Neurology DOI: 10.1001/archneurol.2011.233

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