Sunday, April 5, 2015

Paleolithic Diet Trials: Masharani, et al (2015)


Participants and Diets

25 adults aged 50-69, with type 2 diabetes, were randomised to follow a Paleo diet or the American Diabetes Association diet.  Three meals and three snacks were provided.  An attempt to avoid weight loss was made by calculating maintenance energy needs and then adjusting calorie intake if 3lb (~1.35kg) of weight loss occurred.

“The Paleo diet consisted of meat, fish, poultry, eggs, fruit, vegetables, tree nuts, canola oil, mayonnaise and honey. We excluded dairy products, legumes, cereals, grains, potatoes and products containing potassium chloride. Some foods, such as mayonnaise, carrot juice and domestic meat, were not consumed by hunter gatherers but contain the general nutritional characteristics of pre-agricultural foods.”

In addition, there were 3 ramp up diets for 7 days for those in the Paleo group to “allow for adaptation of the subjects’ intestinal tract and potassium handling systems to adjust to the markedly higher dietary content of the fiber and potassium in the Paleo diet”

The ADA diet is not defined in the paper except for “…containing moderate salt intake, low-fat dairy, whole grains and legumes”, as opposed to the exclusion of these foods in the Paleo diet (excluding added salt, not all salt).  There is also no measurement of what the participants ate, except for macronutrients and some micronutrients.  Calorie intake was identical and macronutrient ratios were fairly similar although the Paleo group had slightly lower protein, fat and SFA; and slightly higher carbohydrate and MUFA.


ADA
Paleo
Energy (kcal)
3000.5
3001.5
Pro:Fat:Carb (%)
20.3:28.8:54.4
18.5:27.0:58.2
SFA:MUFA:PUFA (%)
6.4:13.8:6.1
3.6:14.8:6.3
Sodium (mg)*
4112
1580
Potassium (mg)*
6337
12246
Calcium (mg)
1998
932
Fibre (g)**
15g
42g
* The figures for sodium and potassium intake in the Paleo group are in mmol (the unit they reported), while those for the ADA group seem to be in mg
** The fibre intake in the Paleo group is what you would expect with 3000 calories, a high carbohydrate diet and most of the carbohydrates coming from fruit and vegetables.  The fibre intake in the ADA group is very low and if it’s correct, then the ADA group were probably eating a lot of refined grains rather than whole grains

Results

Glucose control: fasting glucose significantly decreased in the Paleo group, with no change in the ADA group, although the difference between the groups was only P=0.3.  Consequently, fructosamine, a short term marker of glycemic control, significantly decreased in the Paleo group, with no change in the ADA group and a near significant difference between the groups (P=0.06).  HbA1c significantly decreased in both groups, despite no improvement in fasting glucose and fructosamine in the ADA group.  Both groups had minor improvements in insulin sensitivity (P = 0.1 and 0.09 respectively), although among the most insulin resistant participants, those in the Paleo group, but not the ADA group, had a significant improvement in insulin sensitivity (see figure below)

Blood lipids: both groups had decreases in HDL-C, probably due to lower fat intake.  The Paleo group, but not the ADA group, had significant decreases in total-C and LDL-C probably due to both the very low SFA intake and high fibre intake.  Triglycerides almost significantly decreased in the Paleo group, but not the ADA group, despite higher carbohydrate intake and no difference in weight loss and baseline triglycerides, which may be due to high fibre intake.


ADA Diet
Paleo Diet
P Value Between Groups
Difference
P Value
Difference
P Value
Weight (kg)
-2.1±1.9
0.004
-2.4±0.7
<0.001
0.7
Systolic blood pressure
-2±13
0.7
-4±12
0.2
0.6
Diastolic blood pressure
0±12
0.9
-1±6
0.4
0.6
Mean arterial pressure
-1±7
0.8
-2±7
0.3
0.6
HbA1c
-0.18±0.24
0.04
-0.30±0.49
0.04
0.5
Fasting glucose (mmol/l)
+0.6±1.8
0.4
-1.3±1.4
0.008
0.3
Fructosamine (mg/dl)
-3±28
0.7
-34±41
0.009
0.06
Insulin sensitivity
+1.0±1.9
0.1
+1.3±2.6
0.09
0.8
Total-C (mg/dl)
-9±25
0.2
-26±27
0.003
0.2
Trigs (mg/dl)
-5±63
0.8
-23±46
0.08
0.5
HDL-C (mg/dl)
-6±8
0.03
-8±7
0.001
0.5
LDL-C (mg/dl)
-7±17
0.2
-15±22
0.02
0.4
Creatinine clearance
-16±29
0.1
-3±29
0.9
0.2
Urine K/Na**
+0.6±0.3
 <0.0001
+2.0±0.8
<0.0001
0.001
Urine pH
+0.1±0.3
0.7
+0.8±0.5
<0.0001
<0.001
Urine Ca/Creatinine
-2±33
0.9
-45±43
0.002
0.008
* Bold = p < 0.05.  Underline = p < 0.10

** The urinary potassium:sodium ratio reflects dietary intake, and therefore can be used as a marker of compliance.  “Calculation of potassium to sodium ratio confirmed that all the patients, except for one, on the Paleo diet were compliant with the diet”

Lastly, after the trial was over the participants seemed to revert back to their old diets (based on urine sodium and potassium) and consequently the reductions in cholesterol and HbA1c were also reverting back to the usual level. 

2 comments:

  1. The % for protein, fat and carbohydrates total 103.5%? How is that possible?

    ReplyDelete
    Replies
    1. It could be a mistake. It could also be a poor assumption whereby they measure calories, protein, fat and carbs, then multiply P,F,C grams by 4,9,4 respectively (which in itself may produce minor inaccuracies), which of course slightly overestimates carb % due to fibre, etc. If so, this is a good example where calculating carb % by subtraction could be both simpler and more accurate

      Delete