Section I: Introduction
Over 1.5
million to 10,000 years ago, before cultivated plants and domesticated animals,
Homo sapiens evolved and lived nomadic
lifestyles in order to survive (Frassetto, Schloetter,
Mietus-Snyder, Morris, & Sebastian, 2009; Lindeberg, Cordain, & Eaton,
2003). During the Paleolithic time frame, hunting and gathering of food
sources involved traveling on foot an average of 5-10 miles a day (O'Keefe & Cordain, 2004) . Over time, through technological
advances and urbanization, humans have evolved to lead drastically different
lifestyles due to inactivity and overconsumption of highly caloric nutrient
stripped food sources. Today, the
fast food revolution has led to a plethora of chronic diseases, including type
2 diabetes and cardiovascular disease, the most lethal causes of death in the
United States (Frassetto et al., 2009).
Decreasing waist circumference, improving energy intake, and increasing energy
expenditure has been associated with reducing the rates of type 2 diabetes and
improving cardiovascular risk factors (Lindeberg,
et al., 2007; Lindeberg et al., 2003).
In 1985,
anthropologists Eaton and Konner introduced the Paleontology diet that consists
of these outdated food selections: lean meat, fish, nuts, vegetables and fruit
(Frassetto et al., 2009; Lindberg et al., 2003). This diet completely excludes two main food groups, dairy
and carbohydrates, which may be detrimental to health over time. Even, though humans have evolved from
our ancestors the genetics have only slightly changed and certain concepts from
the Paleolithic period should be adopted, such as increasing energy expenditure
and selecting fresh and natural nutrient dense foods (O'Keefe & Cordain, 2004) .
Literature Review
In a crossover 3-month study, the Paleolithic diet and
the current dietary guidelines of the Diabetes diet were compared to assess
cardiovascular risk factors among participants (n= 13) in Sweden (Jonsson, et al., 2009) . The Paleolithic diet included the
following food staples: lean meat, fish, fruit, vegetables, eggs and nuts;
while prohibiting grains, dairy, alcohol, and processed or salted foods. Each participant was randomly assigned
to their group and given information on their dietary regimen. At week six, four-day food records were
administered to estimate energy intake.
According to the findings, the Paleolithic diet showed improvements in
HDL concentrations by 0.08 mg/dL, diastolic blood pressure by 4 mmHg, and
reductions in weight loss of 3 kg, and waist circumference by 4 cm. There was no significant difference in
blood values observed during the oral glucose tolerance test (OGTT).
In comparison, the Paleolithic diet had lower calorie
intake and it consisted of 32+ 7% carbohydrates (CHO) and 24% protein
(PRO). Both calcium and CHO intake
did not meet the recommended amounts in the Paleolithic diet. In general, the daily recommendation
for adults between the ages of 19 to 50 is 1,000 mg of calcium and the
inadequate consumption of the Paleolithic diet of 356+ 102 mg did not
even come close. Calcium is
necessary for bone health and intake has been recently linked to adiposity and
weight loss (Steding, Brevard, & Yesilcacy, 2005) . As shown, it is very difficult to
obtain the daily calcium recommendations in the Paleontology diet by
prohibiting dairy consumption, even if consumption of nutrient rich leafy
vegetables is high (Lindeberg et al., 2003). Limitations in this study would be the
short-duration of the intervention, small sample size, and undisclosed physical
activity amounts.
In another controlled study, the effects of the Mediterranean
and Paleolithic diet were investigated for 12-weeks on patients (n=29) with
ischemic heart disease (IHD) and type 2 diabetes (Lindeberg, et al., 2007) . The male participants were recruited
from a Coronary Care Unit in Sweden and randomly assigned to a group. Then, separately educated on the health
benefits of their diet regimen and regular physical activity. The Mediterranean diet consisted of
whole-grains, low-fat dairy, fruit, legumes, fish, and refined monounsaturated
fats; while the Paleolithic diet was consistent with the previous parameters. Similar to Jonsson et al. (2009), a
four-day food records were administered after 15+5 days in order to
determine the dietary compositions of each group. In the Paleolithic group, total caloric intake was significantly
lower by 25% (p= 0.004) and PRO was 27.9+ 6.8% of the total energy. This percentage almost constitutes as a
high protein diet at 30% and these elevated concentrations have been associated
with impaired renal function (Wheeler, et al.,
2012; Lindeberg et al., 2003).
In the findings, glucose response improved by 36% during
an OGTT in the Paleolithic group and there was only a 7% improvement the control
group. At week six, both groups
decreased AUC insulin by 22%.
After the intervention, the average weight loss was about 4.4 kg and the
waist circumference decreased significantly (p= 0.03) in the Paleontology diet
by 5.6 cm compared to the control group of 2.9 cm. However, the glucose tolerance improvement was not associated
with weight loss or waist reductions in the Paleolithic group. Limitations would be the short
duration, small sample size, and high drop out rate with the Paleolithic diet
(n=3). Also, physical activity was
advised but not recorded and complete nutrient analyses, including calcium,
were undocumented.
In another short-term pilot study, healthy volunteers from
Sweden, between the ages of 20-40 years, assessed the effects of an ad libitum Paleolithic
diet (Osterdahl, Kocturk, Koochek, & Wandell, 2008) . The diet protocol was presented at a seminar
for all male (n=5) and female (n=9) participants, and they recorded their daily
intake in a food diary. However,
due to a computer error, complete food registration for only six subjects was
documented. All participants were
assessed at phase 1 (baseline), phase two (after normal diet at day 7), and phase
3 (after the Paleolithic intervention at day 21). According to the food registrations, total energy intake
decreased by 36%; CHO significantly decreased by 53% and calcium deceased by
53% (395 mg/d). Overtime,
decreased calcium intake has been associated with increased hip factures (Matković, Kostial, Simonović, Buzina, Brodarec,
& Nordin, 1979) .
In comparison
from phase two to phase three, no marked improvements in glucose metabolism
were found but there was a significant weight loss of 2.3 kg (p<0.001), waist
circumference decreased by 0.05 cm, and systolic blood pressure dropped by 3
mmHg (p= 0.03). The rapid weight
loss between these phases was not shown to be linked to exclusively fat loss. Therefore, it is possible that reductions
in lean body mass may have contributed to the significant weight loss. Limitations
to the study would be no control group, small sample size and lack of data on the
complete food registrations.
According to another study by Jönsson et al., the long-term effects of the Paleolithic diet and
cereal-based diet was measured in domestic piglets (n= 24) for 15 months
(2006). At two months of age, the
pigs were randomly assigned to either diet: cereal (17% PRO, 65% CHO) or
Paleolithic (27% PRO, 57% CHO).
Every two weeks body weight was measured and at the end of the study
intravenous glucose tolerance test (IVGTT) was performed following a 6-hour
fast. In comparison, the Paleolithic
fed pigs observed a reduced weight gain of 22%, lower subcutaneous fat of 43%,
shorter length of 6%, and reduced energy intake of 20%. There was no significant difference in
fasting insulin and glucose observed among pigs, but AUC insulin improved by
47%, C-reactive Protein (CRP) was 82% lower (p= 0.0007), and diastolic blood
pressure was 13% lower (p= 0.0007) in the Paleolithic diet. In this particular study, the diets did
not match the macronutrients compositions of the other human studies.
In a controlled study by Frassetto et al., nine sedentary
healthy volunteers were recruited from the San Francisco area to compare the
short-term changes of metabolic variables with the Paleontology diet or usual
diet (2009). All participants were
at or below the standardized VO2max for their age and gender and instructed
to continue their normal physical activity. The participants consumed their normal diet for 3-days,
followed by 7-day ramp-up diet, and then 10-day intervention of a verified
Paleolithic diet. Contrary to
other findings by Lindeberg et al. (2007), no significant change in weight was
observed between groups, however the following lipid panels improved:
triglycerides (35%), total cholesterol (16%), and LDL concentrations (22%). Diastolic blood pressure decreased significantly
by 3.4+2.7 mmHg and the ratio of AUC plasma insulin to plasma glucose decreased
by 40% (p= 0.005) during the glucose tolerance test. Limitations for this study were the short duration, small
sample size, and the absence of a control group.
In Frassetto et al. (2009) study, the normal diet (18%
PRO, 44% CHO, 38% FAT) and prepared Paleolithic diet (30% PRO, 38% CHO, and 32%
FAT) had similar calorie composition in a 68-week study by Brinkworth et al. (2004). The purpose of this longterm study was to observe the
impact of cardiovascular risk factors in obese hyperinsulemic participants assigned
to one of the following diets: high-protein diet (30% PRO, 40% CHO) or standard
protein (15% PRO, 55% CHO). After
the intervention, no changes between groups existed in weight loss, HDL,
insulin sensitivity, and CRP levels indicating poor long-term adherence to the
intervention. According to Greenberg
et al. (2009) study, the greatest weight loss was observed within 6-months of
dieting but the leading factor for long term success was physical
activity. Physical activity was
attributed to other healthy behaviors, such as: reduced energy intake and
improved metabolism and a decrease in chronic disease prognosis. In another study by Ross et al., the
combination of exercise and diet showed elicited a higher fat reduction of 1.3
kg (p=0.03) than the diet only group (2000). In addition, the weight loss was due to fat reductions
exclusively and it improved metabolic rate, strength, insulin sensitivity, and lipid
panels.
Statement
of the Problem
These short-term
Paleolithic diet studies may seem promising for cardiovascular risk factors in
type 2 diabetics but it neglects a major components of energy balance, physical
activity. The long-term
effects of the Paleontology diet on cardiovascular risk factors and bone
mineral density (BMD) within a randomly assigned, large sample size, and
compared to a control group has not been assessed. The purpose of the proposed study is to determine the impact
of the (P) Paleolithic diet, Paleolithic diet and exercise (P+E), Diabetes diet
(D), Diabetes diet and exercise (D+E) on type 2 diabetes and cardiovascular
risk factors over 12-months. The
specific null hypothesis is:
1.
There is no difference in fasting blood values
(plasma glucose and plasma insulin), body weight, body fat, blood pressure, and
cholesterol (total, LDL, and HDL) after the 12-month intervention.
2. There
is no difference between groups on changes in insulin sensitivity, B-cell
function, and bone mineral density after the 12-month study.
3. There is no difference in dietary intake
and nutrient compositions between groups.
Section II: Method
Participants
The
participants were selected using a convenience sample of male and female
volunteers recruited from Medical Center of Plano. All participants were enrolled in the Center of Lifestyle Enhancement
Program for Diabetes Education.
There were 200 participants recruited and the inclusion criteria was
that the participants were: between 45-60 years old, type 2 diabetic, and not taking
any prescribed medication or supplements that would deter from the findings. The definition of diabetic was
consistent with World Health Organization standards, fasting plasma glucose ≥ 7.0mmol/l
or 2–h plasma glucose ≥ 11.1mmol/l (Sartorelli
et al., 2010). Participants were excluded if they had a history of an
acute coronary event or any chronic disease diagnosis, including Osteoporosis that
would interfere with the study (n= 50).
Other participants were excluded if they did not adhere to the dietary
regimen (n = 25) or had unexpected health complications (n= 25).
The
adult subjects were selected from patients at Medical Center of Plano, enrolled
in the Diabetes Education program at the Center of Lifestyle Enhancement, and
lived in the Dallas and Fort Worth area.
There were 100 participants that completed the 12-month study. Participants
were randomly assigned to the following groups: (P) Paleolithic diet,
Paleolithic diet and exercise (P+E), Diabetes diet (D), Diabetes diet and
exercise (D+E). The Institutional Review
Board (IRB) approved the study and all participants were informed of the
objectives of the study and a written informed consent was obtained prior to
the study.
Instruments and Measurements
A
validated self-administered Medical History Questionnaire including
family history, alcohol intake, and the use of any medications were recorded
for each participant. It provided
demographic, personal history, contact and habitual information about the
participants. In order to control
for food restrictions, the groups received written information about their
assigned diet regimen. The
Diabetes diet was in accordance with the general recommendations from the
American Diabetes Association and the Paleolithic diet was in accordance with
the previous parameters from Jonsson, et al.
study (2009). At baseline,
each participant met
with a Registered Dietician (RD) at Medical Center of Plano to discuss and answer
any questions. Then exercise
groups, P+E and D+E, met with an Exercise Physiologist to complete a PAR-Q and
receive information on their exercise program. The exercises consisted of resistance training, flexibility,
and aerobic exercises 3-5 d/week at Medical Center’s Cardiac Rehab Center and
all were in accordance with ACSM’s Guidelines for Diabetic
participants. The three-day
dietary intake was completed by all groups every 2-weeks through a validated
computer software program, Fitness Pal, and analyzed by Food Processor SQL
(Version 10.0) and Nutrition Software (ESHA Research, OR, USA) (Frassetto et al., 2009).
After
an overnight fast (12-14 hours), blood samples was collected in tubes from the
antecubital vein for determination of total cholesterol, HDL, LDL, plasma
glucose and insulin. Plasma
insulin was measured by the chemiluminescent assay (Esoterix, Callabasas
Hills, CA). Plasma glucose was
determined by the hexokinase method with
Abbott Architect analyzer. Hitachi 912 Chemistry Analyzer
by Roche Diagnostics determined total cholesterol, HDL, and LDL content (Sartorelli et al., 2010). Insulin sensitivity and B-cell function
was assessed by the homeostatic model assessment (HOMA) technique by Mattews et
al. (1985), which has shown a good correlation to the gold standard euglycemic
hyperinsulemic clamp (Bonera et al.,
2000; Osterdahl et al., 2008). Insulin
resistance was calculated by the following HOMA-IR formula: fasting serum
insulin (μU/ml) x fasting plasma glucose (mmol/l)/ 22.5. B-cell function was calculated by HOMA-B
formula: 20 × fasting insulin (μIU/ml)/fasting glucose (mmol/ml) − 3.5 (Bonera et al.,
2000). In accordance with ACSM’s Guidelines
for Exercise Testing and Prescription, resting blood pressure, height, and weight were measured. Resting blood pressure was measured in
supine position three separate times and the first Korotoff sound was systolic
and the fifth Korotoff sound was diastolic blood pressure. It was measured using a standard of
mercury and 3M Littmann Master Cardiology Stethoscope and Omron Sphygmomanometer. Salter 200 Academy Mechan Scale, measured weight without shoes or heavy apparel, and height was recorded without shoes
and to the nearest 0.5 cm.
Body
fat percentage and bone mineral density (BMD) was measured by the gold standard
Dual-energy X-ray absorptiometry (DXA) scan. Whole body scans were performed on bone
densitometer Norland XR-36 and body tissue was analyzed with Software 3.7.4 Version
2.1.0 (Norland Corporation, Ft. Atkinson, WI). All scans were performed according to the standard protocol
with participants in supine alignment.
Following each scan, the tester performed a standard calibration and the
precious error for total BMD is 0.75%.
T-scores was calculated and diagnostic criteria was in accordance of the
standard deviations (SD) to the norms: <1 is average BMD, 1-2.5 osteopenia,
and >2.5 osteoporosis (Kohrt, 2011) .
Procedures
The study was 12-months long and prior to the study, the
participants were informed of the study, randomly assigned to a diet group, and
consulted a RD. The exercise groups consulted with the Exercise Physiologist
and followed the exercise regimen 3-5 d/week at the Cardiac Rehab Center. Following an overnight fast
(12-14 hours), blood pressure, weight, height, plasma values, insulin
sensitivity, B-cell function, and the whole body DXA scan were measured at
baseline. The participants were
reminded weekly by email about the study and all received detailed instructions. Each month, the participants met with
the RD to review their diet and three-day food diaries. The exercise groups met with the
Exercise Physiologist each month to address their exercise regimen. Then, after 12-month interval and
following an overnight fast (12-14 hours), blood pressure, weight, height,
plasma values, insulin sensitivity, B-cell function, and whole body DXA scans
were measured again for follow-up.
Design and analysis
The results are expressed as means + SDs or
medians and interquartile ranges are specified. The level of significance was set at 0.05 to make decisions
about the hypothesis. Statistical analyses were conducted by SPSS version 13
(for Windows). Associations
between changes were assessed with the Spearman correlation coefficients. The analysis of variance (ANOVA)
compared the four groups and changes in insulin sensitivity, B-cell function,
and bone mineral density from baseline to after the study. ANOVA was used to compare the total
cholesterol, HDL, LDL, and glucose metabolism in the groups: (P) Paleolithic
diet, Paleolithic diet and exercise (P+E), Diabetes diet (D), Diabetes diet and
exercise (D+E). Linear trends were
used to test any relationship between calcium intake, changes in BMD and
weight.
References
Bonora, E., Targher, G., Alberiche, M., Bonadonna, S. R.,
Monauni, T., & Muggeo, M.
(2000). Homeostasis Model Assessment
Closely Mirrors the Glucose Clamp
Technique in the Assessment of Insulin
Sensitivity. Diabetes Care , 23, 57-63.
Brinkworth, G., Noakes, M., Keogh, J., Luscombe, N., Wittert,
G., & Clifton, P. (2004).
Long-term effects of a high-protein,
low-carbohydrate diet on weight control and
cardiovascular risk markers in obese
hyperinsulinemic subjects. International
Journal
of Obesity , 28, 661-670.
Frassetto, L., Schloetter, M., Mietus-Snyder, M., Morris, R.,
& Sebastian, A. (2009).
Metabolic and physiologic improvements from
consuming a paleolithic, hunter-
gatherer type diet. European Journal of Clinical Nutrition , 63, 947-955.
Greenberg, I., Stampfer, M., Schwarzfuchs, D., Shai, I.,
& Group, D. (2009). Adherence
and success in long-term weight loss diets:
the dietary intervention randomized
controlled trial (DIRECT). J Am Coll Nutr , 28, 159-168.
Jönsson, T., Ahrén, B., Pacini, G., Sundler, F., Wierup, N.,
Steen, S., et al. (2006). A
Paleolithic diet confers higher insulin
sensitivity, lower C-reactive protein and
lower blood pressure than a cereal-based
diet in domestic pigs. Nutrition &
Metabolism , 3 (39), 1-10.
Jonsson, T., Granfeldt, Y., Ahren, B., Branell, U., Palsson,
G., Hansson, A., et al. (2009).
Beneficial effects of a Paleolithic diet on
cardiovascular risk factors in type 2
diabetes: a randomized cross-over pilot
study. Cardiovascular Diabetology , 8
(35), 1-14.
Kohrt, W. (2011 йил 9-Nov.). Osteoporosis. Denton, TX, USA.
Lindeberg, S., Cordain, L., & Eaton, S. (2003).
Biological and Clinical Potential of a
Palaeolithic Diet. Journal of Nutritional & Environmental Medicine , 13, 149-
160.
Lindeberg, S., Jönsson, T., Granfeldt, Y., Borgstrand, E.,
Soffman, J., Sjöström, K., et al.
(2007). A Palaeolithic diet improves
glucose tolerance more than a
Mediterranean-like diet in individuals with
ischaemic heart disease. Diabetologia,
50, 1795–1807.
Matković, V., Kostial, K., Simonović, I., Buzina, R.,
Brodarec, A., & Nordin, B. (1979).
Bone status and fracture rates in two
regions of Yugoslavia. American Journal
Clinical
Nutrition , 32, 540-549.
Metzgar, M., Rideout, T., Fontes-Villalba, M., & Kuipers,
R. (2011). The feasibility of a
Paleolithic diet for low-income consumers. Nutrition Research , 31, 444-451.
O'Keefe, J., & Cordain, L. (2004). Cardiovascular disease
resulting from a diet and
lifestyle at odds with our paleolithic
genome: How to become a 21st-century
hunter-gatherer. Mayo Clinic Proceedings , 79,
101-108.
Osterdahl, M., Kocturk, T., Koochek, A., & Wandell, P.
(2008). Effects of a short term
intervention with a paleolithic diet in
healthy volunteers. European Journal of
Clinical
Nutrition , 62, 682-685.
Ross, R., Dagnone, D., Jones, P., Smith, H., Paddags, A.,
Hudson, R., et al. (2000).
Reduction in obesity and related comorbid
condition after diet-induced weight
loss or exercise-induced weight loss in
men. Annuals of Internal Medicine , 133,
92-103.
Sartorelli, D., Fagherazzi, G., Balkau, B., Touillaud, M.,
Boutron-Ruault, M., Lauzon-
Guillain, B., et al. (2010). Differential
effects of coffee on the risk of type 2
diabetes according to meal consumption in a
French cohort of women: the
E3N/EPIC cohort study. The American Journal of Clinical Nutrition , 91, 1002-
1012.
Steding, J., Brevard, P., & Yesilcacy, Y. (2005). Calcium
intake and percent body fat in
University female athletes. SCAN Pulse , 24, 21-23.
Wheeler, M., Dunbar, S., Jaacks, L., Karmally, W.,
Mayer-Davis, E., Wylie-Rossett, J., et
al. (2012). Macronutrients, Food Groups,
and Eating Patterns in the Management
of Diabetes. Diabetes Care , 35, 434-443.
No comments:
Post a Comment