Karny Jacoby, MD FPMRS

Hello Slate Crossfitters:

February is upon us and enough time has passed since the holidays so that we have forgotten our goals of a no added sugar pure Paleo diet.  This “hot off the press” new article should inspire us to keep up with our mantra of “no added white stuff”!

HbA1c, diabetes and cognitive decline: the English Longitudinal Study of Ageing

A fascinating longitudinal study looking at 5189 participants and comparing multiple cognitive assessments to Hemoglobin A1c levels.  This blood test is a marker of average glucose levels in a person over the past 2-3 months.  It is a common lab test done to diagnose and monitor diabetes and pre-diabetes.  The great thing about this test is that you can’t cheat as it rises or falls with consistent blood glucose control.  

What they showed is that there is a correlation between elevated Hemoglobin A1c levels and cognitive impairment, and that there was a linear association.  This means that with each incremental rise in Hemoglobin A1c, there was also an incremental fall in cognitive skills.  What this also means is that people that were NOT diagnosed as diabetics also had cognitive impairment. When they controlled for lots of other variables the elevated Hemoglobin A1c was the thing that stood out as correlating with the cognitive impairment.

Why would elevated blood sugar lead to cognitive decline?  The authors postulate:

“Diabetes has been implicated to be related to subsequent cognitive impairment through both direct mechanisms (e.g. by inducing amyloid accumulation) and indirect mechanisms (e.g. by increasing microvascular disease of the central nervous system—believed to play a very important role in vascular dementia)”


The thing that is fascinating about this study is that we can all modify our sugar intake and lower our Hemoglobin A1c.  By weight training, our increased muscle mass also acts like a “sink” for glucose and helps to modulate big swings in our blood glucose levels.  

The limits of this study are that it is an observational study so there is no proof of causation, and for that reason we need to see more data…but, the study looks like it’s been well designed and there are other indications in the literature that excessive sugar and simple carbohydrates are detrimental.

Of course, there are other reasons to avoid excessive sugars in our diet; the least of which that it is the cause of obesity along with just too many calories.

So, as the holiday indulgences fade into distant memory, keep in mind that “diets” don’t really work. What works is changing your relationship with food every day for the rest of your life.  Make healthy eating part of your lifestyle. You are what you eat, and our typical American diet consistently challenges your body to adapt in negative ways; in this case, with excessive sugars altering insulin metabolism possibly causing early Dementia.

Happy Open!