Monday, April 18, 2011

Low Carbohydrate Study in Canadian Diabetes Literature

I was planning to write about fasting glucose and minimum carbohydrate levels today, but when I came across this little gem of a study reported in the Canadian Journal of Diabetes in 2006, I just couldn't resist the opportunity to comment.  What first caught my attention was this sentence on page 270:
Low-carbohydrate diets that result in higher intakes in saturated fat may aggravate levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), major risk factors for [coronary heart disease].
I don't have a problem with the first part of the sentence, but I find the term "major risk factors" totally disingenuous when it's coming from the so-called experts.

I wrote about this earlier this monthLow HDL and high triglycerides are known to be the most effective predictors of vascular disease, not total cholesterol and LDLThis is not controversial.  

It is backed up by a recent 33 year Danish study reported in the Annals of Neurology which found that non-fasting triglyceride levels are a better predictor of stroke risk than cholesterol, especially in women.

It's no wonder the public is confused, when the people who know better continue to reference total cholesterol and LDL.

The story continues.  On page 273 we read:
With low-carbohydrate diets, TC, LDL-C and triglyceride (TG) decreased, and HDL-C increased  ... these lipid concentrations increased after 6 and 12 months...

It was concluded that the adverse effect of a greater saturated fat intake associated with the low-carbohydrate diet may have been offset by the greater weight loss in that group.

At 12 months, reductions in serum TG [triglyceride] and increases in HDL-C were seen only with the low-carbohydrate diet.
Notwithstanding the positive findings, high saturated fat intakes, which are often characteristic of low-carbohydrate diets and come mainly from animal protein, have been demonstrated throughout the literature to raise TC and LDL-C.
What is the adverse effect of a greater saturated fat intake?

Bearing in mind that the second sentence suggests no possibility in the writers' minds that saturated fat consumption might actually be beneficial, let me paraphrase the rest - the sarcasm is all mine:  When study participants ate unlimited saturated fat and limited their carbohydrates, their blood work showed improvements in both of the most important measures of coronary heart disease at 6 and 12 months.  This finding is consistent with other studies, but we'll continue to look at the measures that are known to be marginal predictors, at best.  There is no way we could possibly consider a causal relationship between the greater saturated fat intake (combined with lower carbohydrate intake) and these improvements.

Does this sound feasible to you?  Why is it simply not possible for these people to consider that saturated fat might not be the enemy, and that it is the carbohydrates which need to be limited instead?

A little further down on the same page, I also found this comment:
To our knowledge, no study has assessed the risks, benefits and effects of very low-carbohydrate diets on BG control in type 1 diabetes.
Honestly?  I just cannot believe that nobody has studied what happens when you restrict the very nutrient that, in the absence of insulin injections, kills people whose system cannot control it.

Because it is my understanding that 19th and early 20th century physicians did plenty of experimentation, including carb and calorie restriction, on their type 1 diabetic patients in the hopes of figuring out what was going on.

Could they mean there are no current studies?  With all the research and publishing going on today, I am totally flabbergasted that this has not been thoroughly researched.

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