Tag Archives: blood sugar

Higher Blood Sugar Levels Once Again Linked to Dementia

dementia, memory loss, Mediterranean diet, low-carb diet, glycemic index, dementia memory loss

“Let’s work on getting those blood sugars down, honey.”

On the heels of a report finding no association between Alzheimer’s disease and abnormal blood sugar metabolism, MedPageToday features an new study linking high blood sugars to future development of dementia. And diabetics with sugar levels higher than other diabetics were more prone to develop dementia.

Some of you have already noted that not all cases of dementia are Alzheimer’s dementia. But Alzheimer’s accounts for a solid majority of dementia cases.

Some quotes from MedPageToday:

During a median follow-up of 6.8 years, 524 participants [of the 2000 total] developed dementia, consisting of 74 with diabetes and 450 without. Patients without diabetes and who developed dementia had significantly higher average glucose levels in the 5 years before diagnosis of dementia (P=0.01). The difference translated into a hazard ratio of 1.18 (95% CI 1.04-1.33).

Among the patients with diabetes, glucose levels averaged 190 mg/dL in those who developed dementia versus 160 mg/dL in those who did not. The difference represented a 40% increase in the hazard for dementia (HR 1.40, 95% CI 1.12-1.76).

Steve Parker, M.D.

Reference: Crane PK et al. “Glucose Levels and Risk of Dementia” N Engl J Med 2013; 369: 540-548.

Reminder: Conquer Diabetes and Prediabetes is now available on Kindle.

High Normal Blood Sugar Levels Linked To Brain Degeneration

MRI scan of brain

MRI scan of brain

Our 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 diabetes and prediabetes.  They were overwhelmingly 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.

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

Which Are the Low-Carb Veggies?

A half cup of sliced bell pepper has about 2 grams of digestible carbohydrate

Laura Dolson over at About.com has a helpful list of low-carb veggies.  Helpful if you experience excessive blood sugar spikes from high-carb items, or if you’re restricting carbs for weight management.


What Are Glycemic Index and Glycemic Load?

And why should you care?

Because these concepts are related to some common chronic diseases. Diets – i.e., habitual ways of eating – with a high glycemic index or glycemic load increase the risk of type 2 diabetes, coronary heart disease, gallbladder disease, and breast cancer. At least in women.

Glycemic index is a measure of how much a specific food is likely to influence blood sugar (glucose) levels. Carbohydrates we eat, except for fiber, are usually converted by the process of digestion into glucose which we use as fuel. Any glucose not needed immediately for energy is converted into a storage form called glycogen, for use later. We have the capacity to store only a half days’ worth of energy in the form of glycogen. Carbohydrates are converted to fat when eaten in excess of what we can use immediately or store as glycogen.

The standard for glycemic index is set by eating 50 grams of pure glucose, a type of sugar. The pattern of bloodstream glucose levels over the next two hours is given a rank of 100. Oral glucose leads to a more rapid and higher peak in blood sugar compared to nearly all other carbohydrates. All other foods containing carbs (carbohydrates) can be ranked in relation to glucose, on a scale of 0 to 100. Test subjects are given specific foods in whatever serving size contains 50 grams of available carbohydrate, and eaten without other foods. Blood glucose levels are measured repeatedly over the next two hours, and compared to the pattern observed for ingested glucose. The comparison yields a number, the gylcemic index.

Even when they have the same grams of carbohydrate, some foods cause a higher rise in blood sugar. That is, they have a higher glycemic index.

Cashews have a glycemic index (GI) of 22, which means they don’t raise blood sugar nearly as quickly or as much as glucose. An overripe banana has a GI of 52, so it would tend to raise your blood glucose more than cashews. Watermelon’s GI is 72. Doesn’t eating watermelon remind you of drinking flavored sugar water?

With higher GI foods, your body digests and absorbs the foods’ carbs faster, leading to greater release of insulin by the pancreas to reduce the blood sugar levels back to normal.

Some of you have already figured out the the actual rise in blood sugar will depend on other factors, such as how much of the food you eat! To account for the amount of food eaten, the Glycemic Load concept was devised (at Harvard?). You calculate the glycemic load by taking the grams of carbohydrate in the serving size, multiply by the food’s glycemic index, then divide by 100. For example, a cup of white rice has a glycemic load of 33 points; a cup of brown rice has a glycemic load of 23 points.

Remember, the glycemic index is based on the observed blood sugar rise after eating the serving of a food that contains 50 grams of carbohydrate. For example, corn’s glycemic index is 53. One half cup of canned yellow corn has 15.2 grams of carbohydrate. So to get the full glycemic effect, you’d have to eat over one and a half cups of corn. Most people just eat a half cup as a serving. The glycemic load of a half cup of corn is 8 points (15.2 x 53, then divide by 100). Carrots are a classic example of a healthy food with a high glycemic index, but a good/low glycemic load of 2.8 points per half cup (slices, frozen, boiled).

(I’m ignoring for now the grams of nondigestible carbohydrate (fiber) in the corn and carrots.)

Doesn’t this sound just like something you’d like to do at every meal?

Let not your hearts be troubled. You can get most of the pertinent GI’s and GL’s free on the Internet or in various books or pamphlets.  If you’re interested.

Steve Parker, M.D.

(Blood sugar and blood glucose are identical. Glucose is also a simple sugar you can eat. I’ve eschewed the term “blood glucose” today to prevent confusion.)

Additional resources:

Glycemic Index entry at Wikipedia.

For additional information, see Laura Dolson’s good work at About.com.

WebMD.com has an article on factors that affect glycemic index and glycemic load.

Jenkins, D.J., et al. Glycemic index of foods: a physiological basis for carbohydrate exchange. American Journal of Clinical Nutrition, 34 (1981): 362-366. This paper from the University of Toronto introduced the concept of glycemic index to the world.

Nuts Improve Blood Sugar and Cholesterol in Diabetics

Eating nuts improves blood sugar control and cholesterol levels in type 2 diabetics, according to a research report in Diabetes Care.

Canadian researchers randomized 117 type 2 diabetics to eat their usual types of food, but also to be sure to eat either

  • mixed nuts (about 2 ounces a day)
  • muffins (I figure one a day)
  • or half portions of each.

They did this daily for three months. Compared to the muffin group, the full nut group ate quite a bit more monounsaturated fatty acids. (I don’t have full study details because I have access only to the article abstract.)


Hemoglobin A1c, a reliable measure of blood sugar control, fell by 0.21% in the mixed nut group. That’s a move in the right direction. LDL cholesterol, the “bad cholesterol” linked to heart and vascular disease, also dropped significantly.

So What?

The investigators suggest that replacement of certain carbohydrates with 2 ounces of daily mixed nuts is good for people with type 2 diabetes.

I must mention that nuts are a mandatory component of the Ketogenic Mediterranean Diet and the Low-Carb Mediterranean Diet, and a recommended option on the Advanced Mediterranean Diet.

Steve Parker, M.D.

References: Jenkins, David J.A., et al. Nuts as a replacement for carbohydrates in the diabetic diet. Diabetes Care, June 29, 2011. doi: 10.2337/dc11-0338

PS: The lead author of this study is the same David Jenkins of glycemic index fame.