The 12th Invest in ME Conference, Part 1
OverTheHills presents the first article in a series of three about the recent 12th Invest In ME international Conference (IIMEC12) in London.
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Another comparison of low-carb and high-carb diets

Discussion in 'Other Health News and Research' started by MeSci, Dec 18, 2014.

  1. MeSci

    MeSci ME/CFS since 1995; activity level 6?

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    Original Investigation | December 17, 2014

    Effects of High vs Low Glycemic Index of Dietary Carbohydrate on Cardiovascular Disease Risk Factors and Insulin SensitivityThe OmniCarb Randomized Clinical Trial


    Frank M. Sacks, MD1,2; Vincent J. Carey, PhD1; Cheryl A. M. Anderson, PhD, MPH3,7; Edgar R. Miller III, PhD, MD4,5; Trisha Copeland, MS, RD1; Jeanne Charleston, RN, BSN3,4,5; Benjamin J. Harshfield, BA1; Nancy Laranjo, BA1; Phyllis McCarron, MS, RD4; Janis Swain, MS, RD6; Karen White, MS, RDN4; Karen Yee, MS, RD6; Lawrence J. Appel, MD, MPH3,4,5

    JAMA. 2014;312(23):2531-2541. doi:10.1001/jama.2014.16658

    ABSTRACT

    Importance Foods that have similar carbohydrate content can differ in the amount they raise blood glucose. The effects of this property, called the glycemic index, on risk factors for cardiovascular disease and diabetes are not well understood.

    Objective To determine the effect of glycemic index and amount of total dietary carbohydrate on risk factors for cardiovascular disease and diabetes.

    Design, Setting, and Participants Randomized crossover-controlled feeding trial conducted in research units in academic medical centers, in which 163 overweight adults (systolic blood pressure, 120-159 mm Hg) were given 4 complete diets that contained all of their meals, snacks, and calorie-containing beverages, each for 5 weeks, and completed at least 2 study diets. The first participant was enrolled April 1, 2008; the last participant finished December 22, 2010. For any pair of the 4 diets, there were 135 to 150 participants contributing at least 1 primary outcome measure.

    Interventions (1) A high–glycemic index (65% on the glucose scale), high-carbohydrate diet (58% energy); (2) a low–glycemic index (40%), high-carbohydrate diet; (3) a high–glycemic index, low-carbohydrate diet (40% energy); and (4) a low–glycemic index, low-carbohydrate diet. Each diet was based on a healthful DASH-type diet.

    Main Outcomes and Measures The 5 primary outcomes were insulin sensitivity, determined from the areas under the curves of glucose and insulin levels during an oral glucose tolerance test; levels of low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides; and systolic blood pressure.

    Results At high dietary carbohydrate content, the low– compared with high–glycemic index level decreased insulin sensitivity from 8.9 to 7.1 units (−20%, P = .002); increased LDL cholesterol from 139 to 147 mg/dL (6%, P  ≤ .001); and did not affect levels of HDL cholesterol, triglycerides, or blood pressure. At low carbohydrate content, the low– compared with high–glycemic index level did not affect the outcomes except for decreasing triglycerides from 91 to 86 mg/dL (−5%, P = .02). In the primary diet contrast, the low–glycemic index, low-carbohydrate diet, compared with the high–glycemic index, high-carbohydrate diet, did not affect insulin sensitivity, systolic blood pressure, LDL cholesterol, or HDL cholesterol but did lower triglycerides from 111 to 86 mg/dL (−23%, P ≤ .001).

    Conclusions and Relevance In this 5-week controlled feeding study, diets with low glycemic index of dietary carbohydrate, compared with high glycemic index of dietary carbohydrate, did not result in improvements in insulin sensitivity, lipid levels, or systolic blood pressure. In the context of an overall DASH-type diet, using glycemic index to select specific foods may not improve cardiovascular risk factors or insulin resistance.

    Full text here

    I've only had a quick look but note that:


    • All diets seemed low in the percentages of saturated fat which, contrary to persistent belief, may not be a good idea
    • There were significant-looking differences in monounsaturated fat percentages

    The diets were said to be 'healthful', which seems inconsistent with this:

    I find it odd that instant potato and white bread are considered 'healthful'.
     
  2. jimells

    jimells Senior Member

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    Five weeks seems like an awfully short time for a diet study. With all the work and expense of setting up the study, it's too bad they didn't run it for months instead of weeks.

    Thanks for posting this.
     
  3. perchance dreamer

    perchance dreamer Senior Member

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    I couldn't read the article because of some stupid plug-in problem I'm having, so I don't know how they address this.

    Something I find confusing in some of these studies is how they define carbs. I think it should include some vegetables such as avocados, sweet and white potatoes, and winter squashes as well as legumes. However, some studies seem to consider that only foods like grains, sweets, and other foods we all consider junk food are carbs.

    From my reading, the vegetables high in carbs and also legumes are nutritious, but need to be monitored so that we don't eat too many for our activity level or health goals.

    I try to keep that in mind when I go to a Tex Mex restaurant. Instead of eating all these items (like I'd want to!), I pick either the chips, the guacamole, the beans, the rice, or the tortillas. Can't say I'm always successful.
     
  4. MeSci

    MeSci ME/CFS since 1995; activity level 6?

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    Can you access the pdf?

    I'm not sure whether 'available carbohydrate' is the same as/similar to GI in terms of categorising food, but if it is, this page may be helpful in making food choices.

    It's a great site where you can also look up foods by name, by useful nutrients, etc.
     
  5. MeSci

    MeSci ME/CFS since 1995; activity level 6?

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    I thought it seemed rather short too.
     
  6. perchance dreamer

    perchance dreamer Senior Member

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    Thanks, @MeSci, for the links. I was able to read the PDF, and the food chart is helpful.
     
    MeSci likes this.

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