Category Archives: Dementia

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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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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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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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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