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Feb 18

(Note - when I say keep blood sugar levels low - I mean within the acceptable human range, but try for the low end of the spectrum (see below for the ranges). Additionally, try to halt the normal age related increase of blood sugar levels - and keep your levels in the young and healthy range)

Another very simple brain hack for better memory and cognitive function is do what you can to keep low, safe blood sugar levels. Sure someday we might develop drugs to improve your cognitive ability, but you can do something right now to increase your brain ability and that is not to let your blood sugar levels get too high.

Previous research has indicated that diabetics are 1.5 more likely to experience a cognitive decline and dementia (Cukierman et. al., 2005). I don’t think any of you would want to develop dementia. Beyond the increase in dementia in people with diabetes there is also an increase in incidence of Alzheimer’s disease. So what should you do - exercise and eat well so you don’t develop type II diabetes. Lower your intake of carbohydrates, of the carbs you eat try to insure they are low glycemic. And yes volume counts. Instead of just thinking of glycemic index you should think of glycemic load, which is simply glycemic index x the number of grams of carbs for a particular food.

In a new study examining 2,997 diabetics researchers explored the relationship between blood glucose levels (A1C levels) and the performance of 4 cognitive tasks (Cukierman-Yaffe et. al., 2009).


A simple 1% increase in blood sugar levels was linked with lower scores in memory, multiple task management, global cognitive function, and psychomotor speed. Hence, you can see that there was a global decrease in mental ability in those with higher blood sugar levels. The researchers will subsequently examine if lowering blood sugar levels can improve the cognitive ability.

Take home message:

What else can I say to convince you that you must strive to keep your blood sugar levels in the healthy range. Some would even argue if you want to decrease you mental aging you should try for the low end of normal.


Do you even know your blood sugar levels? Or maybe you know one reading - but like blood pressure measurements there can be large difference depending on what you are doing, time of day, and for blood sugar levels obviously when and what you last ate.

One simple and fairly cheap solution to this is that you can buy a blood glucose meter from any drug store and they are realitively cheap (they make money selling the test strips). Go out and buy one and periodically test your blood sugar levels. The simplest measurement you should obtain is your overnight fasting level. This is the one you can best compare to the published and ‘normal range’ levels.

Background info - normal blood sugar values:

Despite widely variable intervals between meals or the occasional consumption of meals with a substantial carbohydrate load, human blood glucose levels normally remain within a remarkably narrow range. In most humans this varies from about 80 mg/dl to perhaps 110 mg/dl (3.9 to 6.0 mmol/litre) except shortly after eating when the blood glucose level rises temporarily (up to maybe 140 mg/dl or a bit more in non-diabetics).

There are many other times that you might find it useful to see what your blood sugar levels are - e.g. after various meals. You can develop your own individual glucose response to foods. Are you getting large spikes after eating X, etc? I will discuss more about this in another piece.

And you might want to consider lowering your carb intake, and of the carbs you eat pick low glycemic ones. You could try a Mediterranean based diet (which is already linked with improved cognitive ability), or any other diet that keep your blood glucose levels at a nice low healthy level.

Very simple daily healthy choices in food selection could go along way in keeping your blood sugar levels low and hence maintain your current cognitive ability - what could be more important than keeping your brain functioning normally.


Jan 28

We would all like to be able to remember better. The following piece offers a potential brain hack to improve your memory ability.

Dietary restriction has repeatedly been show to increase life span in a wide range of organism. However, there has not been much research on humans and therefore many question the use of dietary restriction because of the lack of human data.

Life span studies in humans take a long time and I would think are expensive. However, shorter term studies of dietary restriction in humans are beginning to be published.

Witte et. al., 2009 took 50 healthy mature adults with an average age of 60 in put them into three groups: control, a group that increased their unsaturated fat (the good fat) intake 20% (total fat intake stayed the same), and a 30% calorie restricted group. Memory performance was tested before the intervention and after 3 months being in their designated groups.


Interestingly, the 30% dietary restricted group only lost around 2.5% of their body weight even after being on the restricted diet for 3 months (that would only be 5 pounds if they started out at 200 lbs).

More importantly the 30% dietary restricted group was the only was that showed an improvement in memory (auditory verbal learning task). The researchers were a bit surprised because they were expecting the 20% increase in unsaturated fat group would also improve (next time they will more specifically try to increase the unsaturated fat intake with predominantly increasing fish consumption).

For the dietary restricted group improvement in memory correlated with a decrease in fasting insulin levels, and a decrease in high sensitive C-reactive protein.


I wish the authors had included the raw scores on the memory task (instead of just % of memory improvement) to see if one group started higher or lower than the rest - I assume they all started the same but this was not clearly stated.

And I find it a bit hard to believe that the subjects in the 30% calorie restricted group really were restricted 30% if they only lost 2.5% of their body weight after 3 months.

One could possibly argue there was a placebo effect for those that were put into the dietary restricted group, but this is somewhat countered by the fact that the other intervention group (the 20% increase in unsaturated fats) did not see an improvement in memory.


In healthy late middle aged folks who are ‘normal to overweight’ (BMI in the average range of 27 -29) 30% calorie restriction results in an improvement in memory scores in as little as 3 months time. There you go, human data supporting the beneficial effects of eating less, and who doesn’t want better memory (but will you pay the price).

Even if you are not going to do some form of dieatary restriction try to keep your fasting insulin levels low (at least eat low glycemic food). By lowering your fasting insulin levels you will increase your insulin sensitivity. Also try to alter your lifestyle and diet to reduce your levels of inflammation.

Jul 24

Low levels of the good cholesterol, high-density lipoprotein (HDL), is linked with worse memory performance. So here is another example of what is traditionally considered a heart health measurement that also give us important information about our brain health (see here).

The nice thing about the various cholesterol measurements is that many of you will know your measurements so then you can see where you fall when I provide the details below. If you don’t know your measurements I would suggest you find out - for both your heart and brain health.

You have all heard about cholesterol, but in overly simplistic terms it can be broken down to bad cholesterol, low-density lipoprotein (LDL) and good cholesterol, high-density lipoprotein (HDL) - see wiki entry.

In a recent study by Singh-Manoux et al., 2008 they studied 3,673 subjects at both age 55 and 61 and measured their total cholesterol, HDL, triglycerides (all were measured after an overnight fast), and short term verbal memory. After controlling for all the various variables (e.g. education) they found that subjects with HDL levels <= 40 mg/dL had worse memory than those with high HDL levels (>= 60 mg/dL). Additionally, those subjects that had a drop of HDL from age 55 to 61 also had a drop in memory ability. The authors giving us these results suggest that having HDL levels between the two extremes (41 - 59 mg/dL) does not produce significant differences it is only at the two far ends of the spectrum that differences are found. But these are not extreme values for I know a triathlete that has HDL level is at 96 mg/dL. Additionally, you must remember that subjects that showed a drop in HDL levels over the 6 years between the tests showed a decline in memory - suggesting small changes of HDL are meaningful.

Now if you are in your twenties you might think that this whole cholesterol thing only concerns ‘older’ people. But I can tell you I have a friend in her twenties that HDL was in the 30s, meaning it would fall into the bad memory group (for the record she has a good memory - but what is going to happen when she gets older?). And I know another friend that while he eats very healthy falls into the low category. Therefore, you can not assume that because of your age, eating and exercise habits, body type that you must have a good high level of HDL. So no matter what your age it would not hurt to know your cholesterol and its various sub components.

But more importantly once you find out your measurements to do something about them. We can choose various lifestyles and/or drugs to change our levels to hopefully improve both our body and brain health.

Very quick list of things to do to increase your HDL levels: quit smoking, lose weight, exercise, mild levels of alcohol, increase consumption of good fats (e.g. fish, olive oil, nuts). However, things are never quite this simple. In a future piece I will give you more details that might shock you a bit - it surprised me.

For now find out your various cholesterol measurements when you can, and with or without this knowledge make appropriate lifestyle choices (which we all already know at various levels) that is know to increase your HDL levels - and improve most other health measurements.

(via FuturePundit)