Inﬂuence of Green Leafy Vegetables in Diets with an
Elevated ω-6:ω-3 Fatty Acid Ratio on Rat Blood
Pressure, Plasma Lipids, Antioxidant Status and
Markers of Inﬂammation
Melissa Johnson 1, *, Wendell H. McElhenney 2and Marceline Egnin 2
College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL 36088, USA
Department of Agricultural and Environmental Sciences, College of Agriculture, Environment and Nutrition
Sciences, Tuskegee University, Tuskegee, AL 36088, USA; email@example.com (W.H.M.);
*Correspondence: firstname.lastname@example.org; Tel.: +1-334-727-8625
Received: 12 December 2018; Accepted: 25 January 2019; Published: 31 January 2019
The typical Western dietary pattern has an elevated
-3 fatty acid ratio (FAR), which
may exacerbate the risk of chronic disease. Conversely, the consumption of diets containing green
leafy vegetables (GLVs) have been demonstrated to attenuate disease risk. This study investigated the
effects of collard greens (CG), purslane (PL) and orange ﬂesh sweetpotato greens (SPG) on measures
of disease risk in rats fed diets with a 25:1
-3 FAR. Male spontaneously hypertensive rats
(SHRs) were randomly assigned to four dietary groups (n= 10/group) with a 25:1
Experimental diets contained 4% (dried weight) CG, PL or SPG. Dietary intake, body weight, blood
pressure, plasma adiponectin, high sensitivity C-reactive protein (hsCRP), oxygen radical absorbance
capacity and lipid proﬁle were determined using standardized procedures. Following a 6-week
consumption period, systolic blood pressure, plasma adiponectin, total and low-density lipoprotein
(LDL) cholesterol decreased following the consumption of diets containing GLVs. While hsCRP
increased in SHRs fed diets containing CG and PL, plasma antioxidant capacity was signiﬁcantly
reduced (p< 0.05) with the consumption of diets containing the GLVs. These ﬁndings suggest that
CG, PL and SPG have the potential to decrease risks for cardiovascular disease (CVD) associated
with the consumption of diets with an elevated ω-6:ω-3 FAR.
collard greens; purslane; sweetpotato greens;
-3 fatty acid ratio; cardiovascular
disease; spontaneously hypertensive rat
Hypertension, one of the most common forms of cardiovascular disease (CVD), signiﬁcantly
contributes to morbidity and mortality in the United States as well as globally [
]. Consumption of
the Western dietary pattern, characterized by increased intakes of processed foods, animal products
and relatively minimal intakes of whole grains, fruits and vegetables, is related to increased risk of
hypertension and other CVDs and associated comorbidities [
]. Diets rich in omega-6 (
acids together with the deﬁciency of omega-3 (ω-3) fatty acids, leading to an elevated fatty acid ratio
(FAR), further increases the atherogenicity related to increased disease risk [
]. The current
FAR within the Western diet is estimated to be approximately 25:1 [
]. This imbalance in the
-3 FAR, coupled with traditional Western dietary practices, further exacerbates the increased
risk for hypertension and other CVDs .
Nutrients 2019,11, 301; doi:10.3390/nu11020301 www.mdpi.com/journal/nutrients
Nutrients 2019,11, 301 2 of 14
Risks associated with hypertension and other CVDs may be minimized by engaging in
more prudent dietary practices and increased consumption of diets that contain fruits, vegetables,
whole grains and fatty ﬁsh [
]. Although Americans consume less than recommended
, inclusion of cruciferous and dark green, leafy vegetables (GLVs) into the diet is
particularly emphasized, as consumption has been demonstrated to mitigate the risks associated
with disease pathogenesis and mortality [
]. Collard greens (Brassica oleracea), a traditional GLV
consumed in the southeastern region of the United States, as well as purslane (Portulaca oleracea) and
sweetpotato greens (Ipomoea batatas L.), nontraditional GLVs are established sources of antioxidant and
bioactive compounds that exhibit potent free radical scavenging and antioxidant capabilities [
The nutritional proﬁle of collard greens, purslane and orange ﬂesh sweetpotato greens suggest their
potential functionality in disease prevention and health promotion [25–31].
In light of the potential beneﬁts of collard greens, purslane and sweetpotato greens, coupled
with gaps in knowledge regarding their contribution to health promotion and disease prevention
, research studies are warranted to afﬁrm their inﬂuence on disease risk. Therefore, the purpose
of this research study was to determine the inﬂuence of collard greens, purslane and orange ﬂesh
sweetpotato greens, in diets with an
-3 FAR, reﬂective of the typical Western dietary pattern
(i.e., 25:1), on body weight, systolic blood pressure, plasma adiponectin, high sensitivity c-reactive
protein, oxygen radical absorbance capacity and lipid proﬁle of the spontaneously hypertensive rat.
Furthermore, by expanding our knowledge of these GLVs and their prospective role as functional foods
in disease prevention, dietary recommendations for additional cardiometabloic health and protection
2. Materials and Methods
2.1. Dietary Formulations
The American Institute of Nutrition (AIN)-76A puriﬁed rodent diet was modiﬁed to a ﬁnal
-3 FAR of 25:1; experimental diets included 4% collard greens, purslane and orange ﬂesh
sweetpotato greens powder, respectively (Table 1). Collard greens (purchased from the local farmer’s
market, Tuskegee, AL, USA), purslane and sweet potato greens (purchased from the International
Farmer’s Market, Duluth, GA, USA) were freeze-dried for approximately 48 hours (Virtis Genesis
25SL, Gardiner, NY, USA) and powdered prior to the manufacturing process. The unmodiﬁed
AIN-76A diet served as the standardized control. Control and experimental diets were formulated
to be isonitrogenous and isocaloric. in conjunction with recommendations set forth by the National
Cholesterol Education Program Expert Panel for carbohydrate (50–60% of total calories), protein
(~15% of total calories) and fat (25–35% of total calories- less than 7% saturated fat; up to 10%
polyunsaturated fat; up to 20% monounsaturated fat) (Table 2). The Division of Land O’Lakes Purina
Feed, LLC (Purina TestDiet
, Richmond, IN, USA), manufactured diets; NP Analytical Laboratories
(St. Louis, MO, USA) conﬁrmed speciﬁcations.
Nutrients 2019,11, 301 3 of 14
Table 1. Ingredient composition of experimental diets.
Ingredient (%) Dietary Group *
AIN-76A Control CG PL SPG
Sucrose 50.00 41.96 39.27 39.49 39.39
Casein (Vitamin Free) 20.00 18.00 16.82 16.53 16.68
Corn Starch 15.00 15.00 15.00 15.00 15.00
Powdered Cellulose 5.00 5.00 5.00 5.00 5.00
AIN-76 Mineral Mix 3.50 3.50 3.50 3.50 3.50
AIN-76 Vitamin Mix 1.00 1.00 1.00 1.00 1.00
DL-Methionine 0.30 0.30 0.30 0.30 0.30
Choline Bitartrate 0.20 0.20 0.20 0.20 0.20
Ethoxyquin †0.00 0.00 0.00 0.00 0.00
Corn Oil 5.00 12.06 11.96 12.01 11.97
Soybean oil 2.91 2.88 2.89 2.89
Cholesterol 0.07 0.07 0.07 0.07
Collard Greens 4.00
Sweetpotato Greens 4.00
* CG, collard greens; PL, purslane; SPG, sweetpotato greens. †Ethoxyquin content = 0.0010%.
Table 2. Nutrient composition * of experimental diets.
Nutrient Dietary Group
AIN-76A Control CG PL SPG
Energy, kcal/100 g 370 436 441 436 438
Carbohydrates, % 66.10 60.30 60.30 61.70 61.90
Protein, % 17.20 15.70 16.30 15.20 15.30
Total dietary ﬁber, % 5.95 5.62 7.20 7.41 7.45
Moisture, % 10.00 6.86 5.56 5.55 5.49
Ash, % 2.57 2.53 2.93 3.25 2.96
Total Fat, g/100g 4.10 14.70 14.90 14.20 14.30
SFAs 0.66 2.19 2.25 2.25 2.75
MUFAs 1.17 4.03 3.91 3.61 3.20
PUFAs 1.97 7.47 7.40 6.81 7.39
TFAs 0.05 0.16 0.50 0.82 0.09
Linoleic acid, % 49.40 51.20 49.30 46.6 39.10
Arachidonic acid, % <0.10 <0.10 <0.10 <0.10 0.31
α-Linolenic acid, % 1.08 2.27 2.55 2.76 5.81
Eicosapentaenoic acid, % <0.10 <0.10 <0.10 <0.10 3.68
Docosahexaenoic acid, % <0.10 <0.10 <0.10 0.21 1.69
* CG, collard greens; PL, purslane; SPG, sweetpotato greens; SFAs = saturated fatty acids, MUFAs =
monounsaturated fatty acids, PUFAs = polyunsaturated fatty acids, TFAs = trans fatty acids.
2.2. Animal Feeding
Four-week-old male, spontaneously hypertensive rats (SHRs, n= 50), weighing approximately
60 grams were housed individually in polypropylene cages and maintained on a 12:12 hour light-dark
photoperiod cycle, in a controlled environment (20–22
C; 50–55% relative humidity) with ad libitum
access to water, rodent chow (three days) and AIN-76A puriﬁed rodent diet (seven days) during the
10 days acclimation period. SHRs were randomly assigned to one of ﬁve dietary groups (AIN-76A
(standardized control), control, CG, PL or SPG) and consumed the diets for 6 weeks. Animals were
pair-fed according to the average dietary intake of SHRs assigned to diets containing GLVs. Food
intake and body weight were measured daily and once a week, respectively. Following the completion
of the six weeks feeding trial, SHRs were anesthetized using a Ketamine/Acepromazine combination
cocktail (75–100 mg/kg body weight) and subsequently euthanized via the over-inhalation of carbon
dioxide. Blood was collected via cardiac puncture; SHR organs were removed and stored at
Nutrients 2019,11, 301 4 of 14
prior to analysis. The Tuskegee University Animal Care and Use Committee (Tuskegee, AL 36088)
approved the protocols involved in the care and use of animals for this research study, in accordance
with standards established by the National Institutes of Health.
2.3. Systolic Blood Pressure
Weekly systolic blood pressure measurements were measured utilizing the noninvasive tail
cuff blood pressure (NIBP) system (ML 125/M, ADInstruments, Inc., Colorado Springs, CO, USA)
according to manufacturer’s instructions.
2.4. Adiponectin and hsCRP
Plasma adiponectin and high sensitivity C-reactive protein (hsCRP) concentrations were
determined using the adiponectin rat ELISA kit (Abcam
, Cambridge, MA, USA) and the rat
C-reactive protein ELISA kit (Helica Biosystems, Santa Ana, CA, USA), respectively. Adiponectin and
hsCRP concentrations were estimated based on optical density values obtained from standard curves,
measured at 450 nm using a BioTek®Microplate Reader (Winooski, VT, USA).
2.5. Antioxidant Capacity
SHR plasma antioxidant capacity was determined using the OxiSelect Oxygen Radical Antioxidant
Capacity (ORAC) activity kit (Cell Biolabs, San Diego, CA, USA) according to manufacturer’s protocol.
ORAC values, expressed as
Moles of TroloxTM Equivalents (TE) were calculated based on the
TroloxTM antioxidant standard curve. The area under the curve (AUC) was calculated using the
AUC= 1 + RFU5/RFU0 + RFU10/RFU0 + . . . .. . RFU55/RFU0 + RFU60/RFU0 (1)
where, RFU0 = relative ﬂuorescence value at time point zero and RFUx = relative ﬂuorescence value at
time points (e.g., minute 5, minute 10 . . . .. . minute 55, minute 60).
2.6. Lipid Proﬁle: Plasma Triglycerides, Total Cholesterol, High-Density Lipoprotein- Cholesterol (HDL-C) and
Low-Density Lipoprotein-Cholesterol (LDL-C) + Very Low-Density Lipoprotein-Cholesterol (VLDL-C)
Plasma total cholesterol (Abcam
Inc., Cambridge, MA, USA), triglyceride (Abcam
Cambridge, MA, USA), HDL-C (Abcam
Inc., Cambridge, MA, USA) and LDL-C + VLDL-C
Inc., Cambridge, MA, USA) concentrations were determined using assay kits, according to
manufacturer’s instructions. Sample and standard(s) optical density values were measured at 450 nm
using a BioTek®Microplate Reader (Winooski, VT, USA).
2.7. Statistical Analysis
Data are presented as mean + SEM. Statistical analyses were performed using the GLM procedure
(SAS Institute, Inc., Cary, NC, USA). When the omnibus F test was declared signiﬁcant, Duncan’s
procedure was used to compare group means. The level of signiﬁcance was p< 0.05.
3.1. Dietary Intake, Body Weight
No differences (p> 0.05) in dietary intake throughout the duration of the feeding study were
observed among SHRs (Table 3). Although there were similar average dietary intakes at week 1
(initial dietary intake) and total dietary intakes among SHRs, SHRs assigned to the PL dietary
group consumed slightly more than those assigned to the other dietary groups at week 6. While
SHRs assigned to the different dietary groups had similar body weights at baseline and during the
Nutrients 2019,11, 301 5 of 14
commencement of the feeding study, at week 6 groups fed diets with a 25:1
-3 FAR were heavier
(p< 0.05) than those consuming the AIN-76A diet.
Table 3. SHR dietary intake and body weight.
AIN-76A 11.8 ±0.4 a13.8 ±1.6 a81.5 ±3.3 a65.3 ±5.0 a147.1 ±8.0 a252.9 ±9.1 a
Control 11.7 ±0.3 a13.6 ±1.6 a80.4 ±3.5 a66.4 ±6.7 a146.5 ±9.6 a284.7 ±13.2 b
CG 11.9 ±0.4 a13.8 ±1.6 a81.5 ±3.4 a63.5 ±8.0 a149.2 ±11.9 a290.8 ±9.9 b
PL 11.6 ±0.6 a14.1 ±1.6 a80.6 ±4.8 a60.9 ±6.9 a143.5 ±11.4 a285.6 ±16.2 b
SPG 11.8 ±0.4 a13.9 ±1.5 a81.0 ±3.7 a65.8 ±8.2 a148.7 ±10.0 a285.3 ±11.9 b
Data are expressed as mean
SEM of 10 SHRs per dietary group; Different superscript alphabet (i.e., a, b, c) within
a column indicate statistical signiﬁcance (p< 0.05) between dietary groups.
Initial dietary intake- average dietary
intake at week 1; Final dietary intake—average dietary intake at week 6; Total dietary intake—average total dietary
intake, week 1–week 6; Initial body weight—average body weight at week 1; Final body weight—average body
weight at week 6.
3.2. Systolic Blood Pressure
Beginning at week 3, average systolic blood pressure decreased in SHRs consuming diets
containing CG, PL and SPG in comparison to those consuming the AIN-76A and control diets (Figure 1).
At week 6, consumption of the CG (173.4 mmHg) diet resulted in a decrease (p< 0.05) in systolic blood
pressure compared to the AIN-76A (181.4 mmHg) and control (181.1 mmHg) diets. Among SHRs
consuming diets containing GLVs, CG were able to modulate slightly greater non-signiﬁcant decreases
in systolic blood pressure in comparison to PL and SPG.
Nutrients 2019, 11 FOR PEER REVIEW 6
Figure 1. Mean systolic blood pressure of SHRs consuming the AIN-76A diet and diets with a 25:1 ω-
6/ω-3 FAR for 6 weeks.
3.3. Adiponectin and hsCRP
SHR plasma adiponectin and hsCRP concentrations are presented in Table 4. Plasma
adiponectin levels were significantly reduced (p < 0.05) among SHRs consuming the PL (29.5 μg/mL)
diet versus those consuming the AIN-76A (43.0 μg/mL) and C (38.6 μg/mL) diets. Although not
statistically significant, plasma adiponectin levels were reduced among SHRs assigned to the CG
(35.1 μg/mL) and SPG (31.5 μg/mL) dietary groups. Among SHRs assigned to the different dietary
groups, the lowest hsCRP levels were present in the plasma of those consuming the SPG diet (1084.2
μg/mL) followed by those consuming the C diet (1092.2 μg/mL). Diets containing CG (1164.0 μg/mL)
and PL (1452.0 μg/mL) resulted in decreased plasma hsCRP concentrations.
Table 4. Mean plasma adiponectin and hsCRP concentrations of SHRs consuming the AIN-76A diet
and diets with a 25:1 ω-6/ω-3 FAR for 6 weeks.
Variable Dietary Group
AIN-76A Control CG PL SPG
APN (μg/ml) 43.0 ± 1.7 a 38.6 ± 1.6 ab 35.1 ± 2.3 abc 29.5 ± 2.8 c 31.5 ± 4.0 bc
hsCRP (μg/ml) 397.0 ± 52.5 a 1092.2 ± 168.2 b 1164.0 ± 209.2 b 1452.0 ± 302.0 b 1084.2 ± 87.9 b
a Data are expressed as mean ± SEM of 6 SHRs per dietary group; Different superscript alphabet (i.e.,
a, b, c) within a row indicate statistical significance (p < 0.05) between dietary groups. APN,
adiponectin; hsCRP, high sensitivity C-reactive protein.
3.4. Antioxidant Capacity
The antioxidant capacity of SHR plasma was significantly reduced following the consumption
of the CG (5.8 mMole/TE), PL (5.6 mMole/TE) and SPG (5.6 mMole/TE) diets (Figure 2).
Systolic Blood Pressure (mmHg)
Mean systolic blood pressure of SHRs consuming the AIN-76A diet and diets with a 25:1
ω-6/ω-3 FAR for 6 weeks.
3.3. Adiponectin and hsCRP
SHR plasma adiponectin and hsCRP concentrations are presented in Table 4. Plasma adiponectin
levels were signiﬁcantly reduced (p< 0.05) among SHRs consuming the PL (29.5
g/mL) diet versus
those consuming the AIN-76A (43.0
g/mL) and C (38.6
g/mL) diets. Although not statistically
signiﬁcant, plasma adiponectin levels were reduced among SHRs assigned to the CG (35.1
Nutrients 2019,11, 301 6 of 14
and SPG (31.5
g/mL) dietary groups. Among SHRs assigned to the different dietary groups, the
lowest hsCRP levels were present in the plasma of those consuming the SPG diet (1084.2
followed by those consuming the C diet (1092.2
g/mL). Diets containing CG (1164.0
g/mL) and PL
(1452.0 µg/mL) resulted in decreased plasma hsCRP concentrations.
Mean plasma adiponectin and hsCRP concentrations of SHRs consuming the AIN-76A diet
and diets with a 25:1 ω-6/ω-3 FAR for 6 weeks.
Variable Dietary Group
AIN-76A Control CG PL SPG
APN (µg/mL) 43.0 ±1.7 a38.6 ±1.6 ab 35.1 ±2.3 abc 29.5 ±2.8 c31.5 ±4.0 bc
hsCRP (µg/mL) 397.0 ±52.5 a1092.2 ±168.2 b1164.0 ±209.2 b1452.0 ±302.0 b1084.2 ±87.9 b
Data are expressed as mean
SEM of 6 SHRs per dietary group; Different superscript alphabet (i.e., a, b, c) within a
row indicate statistical signiﬁcance (p< 0.05) between dietary groups. APN, adiponectin; hsCRP, high sensitivity
3.4. Antioxidant Capacity
The antioxidant capacity of SHR plasma was signiﬁcantly reduced following the consumption of
the CG (5.8 mMole/TE), PL (5.6 mMole/TE) and SPG (5.6 mMole/TE) diets (Figure 2).
Nutrients 2019, 11 FOR PEER REVIEW 7
Figure 2. Mean plasma ORAC concentration of SHRs consuming the AIN-76A diet and diets with a
25:1 ω-6/ω-3 FAR for 6 weeks. Results are presented as mean ± SEM mMole TE/L of 10 SHRs per
dietary group; bars with different alphabetical superscripts indicate statistical significance at p < 0.05
according to Duncan’s post hoc test values.
3.5. Lipid Profile
In comparison to the control diet (97.0 mg/dL), triglyceride levels were increased among SHRs
consuming the PL (113.0 mg/dL) and SPG (118.4 mg/dL) diets and decreased following the
consumption of the CG diet (92.2 mg/dL) (Table 5). Although not significant, total cholesterol and
LDL-C + VLDL-C levels were decreased among SHRs consuming the CG, PL and SPG diets in
comparison to the AIN-76A and control diets. In comparison to the control diet (33.7 mg/dL), levels
of HDL-C were increased among SHRs consuming the CG (38.7 mg/dL) and PL (41.3 mg/dL) diets.
Table 5. Plasma lipid profile of SHRs consuming the AIN-76A diet and diets with a 25:1 ω-6/ω-3 FAR
for 6 weeks.
Variable Dietary Group
AIN-76A Control CG PL SPG
TAG (mg/dL) 150.1 ± 7.2
97.0 ± 4.2
92.2 ± 7.3
113.0 ± 4.0
118.4 ± 12.6
TC (mg/dL) 75.5 ± 11.8
64.1 ± 2.8
62.5 ± 3.1
61.6 ± 2.5
58.0 ± 2.3
HDL-C (mg/dL) 39.2 ± 2.5
33.7 ± 2.6
38.7 ± 1.9
41.3 ± 1.3
19.4 ± 6.6
LDL-C + VLDL-C (mg/dL) 10.5 ± 3.6
15.1 ± 1.2
12.6 ± 1.5
10.5 ± 0.6
11.2 ± 0.98
Data are presented as mean ± SEM of 10 SHRs per dietary group. Rows with different alphabetical
superscripts (i.e., a, b, c) indicate statistical significance at p < 0.05 according to Duncan’s post hoc test
values. TAG: triglyceride (mg/dL); TC: total cholesterol (mg/dL); HDL-C: high-density lipoprotein
cholesterol (mg/dL); LDL-C + VLDL-C: low-density lipoprotein cholesterol + very low-density
lipoprotein cholesterol (mg/dL).
The imbalance in the ω-6/ω-3 FAR (e.g., 25:1), as seen in traditional Western dietary practices,
further exacerbated the increased risk of hypertension and other CVDs risk factors as demonstrated
in the present study. Throughout the duration of the study, as well as at the conclusion of the
AIN-76A 25:1 C 25:1 CG 25:1 PL 25:1 SPG
ORAC Value mMole Trolox Equivalents (TE)
b b b
Mean plasma ORAC concentration of SHRs consuming the AIN-76A diet and diets with a
-3 FAR for 6 weeks. Results are presented as mean
SEM mMole TE/L of 10 SHRs per
dietary group; bars with different alphabetical superscripts indicate statistical signiﬁcance at p< 0.05
according to Duncan’s post hoc test values.
3.5. Lipid Proﬁle
In comparison to the control diet (97.0 mg/dL), triglyceride levels were increased among
SHRs consuming the PL (113.0 mg/dL) and SPG (118.4 mg/dL) diets and decreased following the
consumption of the CG diet (92.2 mg/dL) (Table 5). Although not signiﬁcant, total cholesterol and
LDL-C + VLDL-C levels were decreased among SHRs consuming the CG, PL and SPG diets in
comparison to the AIN-76A and control diets. In comparison to the control diet (33.7 mg/dL), levels of
HDL-C were increased among SHRs consuming the CG (38.7 mg/dL) and PL (41.3 mg/dL) diets.
Nutrients 2019,11, 301 7 of 14
Plasma lipid proﬁle of SHRs consuming the AIN-76A diet and diets with a 25:1
for 6 weeks.
Variable Dietary Group
AIN-76A Control CG PL SPG
TAG (mg/dL) 150.1 ±7.2 a97.0 ±4.2 c92.2 ±7.3 c113.0 ±4.0 bc 118.4 ±12.6 b
TC (mg/dL) 75.5 ±11.8 a64.1 ±2.8 a62.5 ±3.1 a61.6 ±2.5 a58.0 ±2.3 a
HDL-C (mg/dL) 39.2 ±2.5 a33.7 ±2.6 a38.7 ±1.9 a41.3 ±1.3 a19.4 ±6.6 b
LDL-C + VLDL-C (mg/dL) 10.5 ±3.6 a15.1 ±1.2 a12.6 ±1.5 a10.5 ±0.6 a11.2 ±0.98 a
Data are presented as mean
SEM of 10 SHRs per dietary group. Rows with different alphabetical superscripts
(i.e., a, b, c) indicate statistical signiﬁcance at p< 0.05 according to Duncan’s post hoc test values. TAG: triglyceride
(mg/dL); TC: total cholesterol (mg/dL); HDL-C: high-density lipoprotein cholesterol (mg/dL); LDL-C + VLDL-C:
low-density lipoprotein cholesterol + very low-density lipoprotein cholesterol (mg/dL).
The imbalance in the
-3 FAR (e.g., 25:1), as seen in traditional Western dietary practices,
further exacerbated the increased risk of hypertension and other CVDs risk factors as demonstrated in
the present study. Throughout the duration of the study, as well as at the conclusion of the research,
SHRs consuming the control, CG, PL and SPG diets weighed signiﬁcantly more than those consuming
the AIN-76A diet, possibly explained by the caloric density of the AIN-76A diet. AIN-76A diet had
fewer calories per 100 grams and less than 3 times the amount of total fat. The ability of diets containing
CG, PL and SPG to promote an attenuation in systolic blood pressure corroborate previous research
demonstrating the ability of cruciferous and green, leafy vegetables to reduce blood pressure and
reduce the risks associated with CVD [
]. The reduction in blood pressure is probably attributed
to the vasodilative and subsequent antihypertensive effects of the antioxidant compounds such as
quercetin, which is commonly found in these vegetables [35–38].
Levels of adiponectin, an adipose-speciﬁc protein, are inversely associated with levels of
]. Consequently, lower levels of adiponectin are linked to increased risk for obesity,
insulin resistance, diabetes, cardiovascular and other diseases [
]. Increases in plasma adiponectin
concentrations have been observed with the obstruction of the renin-angiotensin system [
HDL concentrations, and decreased body mass index [
]. The consumption of purslane seeds for
16 weeks resulted in signiﬁcant decreases in blood glucose, LDL cholesterol, total cholesterol and
triglycerides and a signiﬁcant increase in HDL cholesterol [
]. Additionally, purslane has been
demonstrated to reduce the risks associated with oxidative stress, cardiovascular disease and other
]. In a study by Hussein purslane extract incorporated into a high-fat diet was able to
inhibit weight gain and improve insulin resistance [
]. Although adiponectin concentrations were not
measured in this study, one would anticipate increased levels of adiponectin based on its relationship
with the parameters studied.
In the present study, plasma adiponectin was not increased in SHRs consuming diets containing
CG, PL and SPG. Research suggests a positive relationship with omega-3 fatty acid supplementation
and adiponectin, with adiponectin levels increasing with increasing omega-3 fatty acid
Furthermore, it has been suggested that the risk for obesity increases with an increase in the
omega-6/omega-3 fatty acid ratio . The elevated omega-6/omega-3 fatty acid ratio in the current
study may in part explain the reductions in plasma adiponectin. Dietary fat is hypothesized to decrease
adiponectin levels by increasing susceptibility to weight gain, obesity and inﬂammation [
While decreases in plasma adiponectin concentrations have been reported with increased dietary
], others have reported plasma adiponectin concentrations to be positively associated with total
dietary fat intake [
]; high fat intakes have also been reported to exert no inﬂuence on adiponectin
]. Consequently, research ﬁndings concerning the relationship between dietary
fat and adiponectin concentrations are inconclusive. Although some of current ﬁndings of this study
were not in agreement with previous research, it is hypothesized that longer term feeding of diets may
Nutrients 2019,11, 301 8 of 14
enhance the clinical cardioprotecive effects of the GLVs within diets with an elevated omega-6/omega-3
fatty acid ratio.
In addition to dietary fat, the dietary ﬁber and antioxidant compounds contained in CG, PL
and SPG may have inﬂuenced SHR plasma adiponectin concentrations. Research has afﬁrmed that
increased diet quality (e.g., increased consumption of whole grains, fruit, vegetables, nuts/legumes,
long-chain fats, and PUFAs) favorable inﬂuences plasma biomarkers such as adiponectin [
Increased consumption of fruits and vegetables, rich plant sources of dietary antioxidants, have
been connected with increased antioxidant concentrations associated with increased adiponectin
] as well as decreased central adiposity and oxidative stress. The importance
of individual dietary constituents acting in synergy during nutrient metabolism, more speciﬁcally
dietary ﬁber and dietary antioxidants, has recently been highlighted as dietary ﬁber may act as a
carrier of antioxidants and assist in transport [
]. However, in the current study the mechanisms
and effectiveness of dietary ﬁber as a carrier for dietary antioxidants and subsequent inﬂuence on
adiponectin concentrations were not determined. Furthermore, dietary ﬁber has been demonstrated to
signiﬁcantly interact with the adiponectin gene polymorphism to inﬂuence adiponectin concentration,
with GG homozygotic individuals displaying signiﬁcantly greater adiponectin concentrations, even
with low ﬁber intake [
]. In addition, it has been indicated that the total antioxidant capacity
of the diet is related to central adiposity and disease risk, with individuals having greater dietary
antioxidant capacities exhibiting less central adiposity and disease risk (i.e., higher HDL-C, lower
triglyceride concentration, total cholesterol: HDL-C ratio and LDL-C) [
]. Because diets containing
GLVs contained greater dietary ﬁber and antioxidant concentrations, it would be expected that these
diets would elicit signiﬁcantly greater antioxidant and adiponectin concentrations in the SHR as well.
Unfortunately, our ﬁndings did not meet this expectation.
In addition, increased plasma hsCRP levels among SHRs consuming the PL and SPG diets may
be related to lower plasma adiponectin concentrations. The ability of adiponectin to regulate CRP
synthesis has been demonstrated, with higher levels of adiponectin suppressing the synthesis of CRP
in endothelial cells [
]. Research indicates higher dietary antioxidant capacities to be positively
associated with increased adiponectin levels [
] and decreased CRP levels [
]. Higher levels of
(dietary) antioxidants are believed to indirectly increase adiponectin concentrations by decreasing
oxidative stress, which reduces the expression of adiponectin [
]. The lower plasma antioxidant
capacities, as shown in this research, among SHRs consuming diets containing GLVs- rich sources of
antioxidant compounds, versus those consuming diets void of GLVs may be attributed to factors such
as decreased antioxidant bioavailability (e.g., interactions with other nutrients and components of the
food matrix) and the physiological status of the SHRs [68,69].
Kahlon et al., demonstrated the ability of CG to exert a hypocholesterolemic effect
the inﬂuence of which was signiﬁcantly enhanced following steam cooking [
]. The observed
hypocholesterolemic ability of CG in this research is believed to be attributed to antioxidant compounds
(e.g., sulforaphane, isothiocyanates) and other nutrient fractions, as well as physical and chemical
conformational changes that inﬂuence hydrophobicity, active binding sites and the stimulation of the
synthesis of detoxifying enzymes that facilitate the binding and excretion of bile acids. The increased
fecal excretion of bile acids, reductions in both serum and liver total cholesterol and reduced liver
triglycerides have been observed in male Sprague-Dawley rats fed cholesterol-free diets containing
5% SPG for 4 weeks; all observations were statistically signiﬁcant with the exception of serum total
]. Besides the polyphenol and sterols present in SPG, insoluble dietary ﬁbers and
water-soluble viscous polysaccharides are suggested to participate in the hypocholesterolemic process.
In the present study, feeding CG, PL and SPG all exerted a non-signiﬁcant hypocholesterolemic
effect; a non-signiﬁcant hypotriglycemic effect was observed following the consumption of the CG
diet. The hypocholesterolemic effects of vegetables may be explained in part by the presence of dietary
ﬁbers, which bind bile acids for excretion, stimulate the conversion of free cholesterol to bile acid(s) and
impede cholesterol synthesis [
]. The increased HDL-C levels following the consumption of diets
Nutrients 2019,11, 301 9 of 14
containing CG and PL, although not statistically signiﬁcant, are in agreement with ﬁndings correlating
vegetable consumption to increased HDL-C levels [
]. Furthermore, increased consumption of dietary
ﬁber from vegetable products has been associated with decreased total cholesterol, plasma C-reactive
protein and LDL-C, in addition to increased HDL-C and decreased risk for cardiovascular and other
]. This is of particular signiﬁcance as HDL-C is inversely related to CVD risk and
mortality, with individuals with higher HDL-C levels often demonstrating lower disease risk and
]. Other research has revealed the ability of CG, PL and SPG to inﬂuence the erythrocyte
fatty acid proﬁle of spontaneously hypertensive rats .
Reductions in systolic blood pressure and total cholesterol among SHRs consuming diets
containing GLVs in this study suggest the potential mediation of these parameters by tissue omega-3
fatty acids. Although ﬁndings have been inconclusive, generally increasing dietary omega-3 fatty acids
have been associated with decreased risk for CVD risk, exhibited in inﬂuences on hsCRP, triglycerides,
LDL-C and HDL-C [
]. Mechanisms by which omega-3 fatty acids reduce CVD risk include mediating
eicosanoid metabolism and gene expression, increased endothelial relaxation, as well as decreasing
platelet aggregation, triglyceride levels, blood pressure [
]. However, many of these mechanisms
Although the current research study did not focus on the mechanisms whereby which the
nutritional, chemical, antioxidant and bioactive compounds within the GLVs were able to mitigate the
risks for CVD, several metabolic pathways may be initiated or suppressed that may to some extent
offer insight to the observed ﬁndings. For example, reductions in oxidative stress, inﬂammation, blood
pressure and improved endothelial function may be mediated by compounds such as nitrates [
], ﬂavonoids [
], polyphenols [
] and omega-3 fatty acids [
], which are
commonly found in GLVs such as collard greens, purslane and sweet potato greens. While brown
and white adipose tissue levels were not measured, research has demonstrated that these tissues
play a vital role in lipid storage, endocrine function, adipokine concentrations and inﬂammation [
Understanding the functioning and mechanisms of speciﬁc compounds within these GLVs may also
potentially provide awareness regarding the differential effects of GLVs on lipid proﬁle (e.g., TC, TAG,
HDL-C, LDL-C), oxidative status and adipokine concentrations.
The increased risk for high blood pressure and other cardiovascular diseases, the leading cause
of morbidity and mortality in the United States, is associated with the consumption of diets rich in
-6 fatty acids and other atherogenic dietary components (e.g., excessive saturated fats, trans fats,
cholesterol, and sodium). This research study examined the inﬂuence of traditional and nontraditional
GLVs on disease risk, when incorporated into diets with an
-3 FAR reﬂective of the typical
American diet (i.e., 25:1). The ability of these GLVs to favorably modulate blood pressure and lipid
metabolism within an animal model predisposed to developing hypertension was made evident.
Dietary ﬁbers, antioxidant compounds and
-3 fatty acids contained in these GLVs are believed to act
in synergy to modulate blood pressure, gene expression, inﬂammatory process, lipid and lipoprotein
concentrations. These facts lead to the question of the impact of other
-3 FARs on the same
metabolic parameters measured in the study.
As the SHR is an animal model commonly employed to investigate the mechanisms of high
blood pressure pathogenesis and progression and extrapolation to humans, the ﬁndings of this
research may have implications for human health. Based on past and current research ﬁndings,
particular emphasis should be placed on the inclusion of collard greens, purslane and sweet
potato greens into an integrative dietary intervention to prevent high blood pressure, dyslipidemia
(i.e., hypercholesterolemia, hypertriglyceridemia), and inﬂammation associated with CVD. In addition
to CVD, risks associated with other diseases such as atherosclerosis, diabetes, cancer and other
inﬂammatory conditions may potentially be reduced as well with the consumption of these vegetables.
Results of this study contribute to the emergent body of evidence supporting the additive and
Nutrients 2019,11, 301 10 of 14
synergistic contributions of dietary constituents such as dietary ﬁbers, antioxidants, bioactive
compounds and fatty acids, to health promotion and disease prevention. Future research studies
may want to consider the inclusion of measurements of additional inﬂammatory cytokines (e.g., IL-6,
IL-1, TNF-, etc.), endothelial function, genotypic and phenotypic modiﬁcations, lipid metabolism and
aggregate cardiometabolic effects of collard greens, purslane and sweetpotato greens.
M.J. conceptualized the research, conducted the research experiment and wrote the
original draft of the manuscript; M.E. assisted in the hsCRP assay; W.H.M. assisted in the statistical analysis of the
data; M.J., M.E. and W.H.M. edited and revised the manuscript prior to submission.
This research was funded by the Tuskegee University College of Agriculture, Environment and Nutrition
Sciences and The George Washington Carver Agricultural Experiment Station.
Conﬂicts of Interest: The authors declare no conﬂict of interest.
Benjamin, E.J.; Virani, S.S.; Callaway, C.W.; Chamberlain, A.M.; Chang, A.R.; Cheng, S.; Chiuve, S.E.;
Cushman, M.; Delling, F.N.; Deo, R. Heart disease and stroke statistics—2018 update: A report from the
American Heart Association. Circulation 2018,137, e67–e492. [CrossRef] [PubMed]
Medina-Remón, A.; Kirwan, R.; Lamuela-Raventós, R.M.; Estruch, R. Dietary patterns and the risk of obesity,
type 2 diabetes mellitus, cardiovascular diseases, asthma, and neurodegenerative diseases. Crit. Rev. Food
Sci. Nutr. 2018,58, 262–296. [CrossRef] [PubMed]
Monge, A.; Lajous, M.; Ortiz-Panozo, E.; Rodríguez, B.L.; Góngora, J.J.; López-Ridaura, R.J.N.J. Western and
Modern Mexican dietary patterns are directly associated with incident hypertension in Mexican women:
A prospective follow-up study. Nutr. J. 2018,17, 21. [CrossRef] [PubMed]
Hojhabrimanesh, A.; Akhlaghi, M.; Rahmani, E.; Amanat, S.; Ateﬁ, M.; Najaﬁ, M.; Hashemzadeh, M.;
Salehi, S.; Faghih, S. A Western dietary pattern is associated with higher blood pressure in Iranian adolescents.
Eur. J. Nutr. 2017,56, 399–408. [CrossRef] [PubMed]
Fanelli Kuczmarski, M.; Bodt, B.A.; Stave Shupe, E.; Zonderman, A.B.; Evans, M.K. Dietary Patterns
Associated with Lower 10-Year Atherosclerotic Cardiovascular Disease Risk among Urban African-American
and White Adults Consuming Western Diets. Nutrients 2018,10, 158. [CrossRef]
Drake, I.; Sonestedt, E.; Ericson, U.; Wallström, P.; Orho-Melander, M. A Western dietary pattern is
prospectively associated with cardio-metabolic traits and incidence of the metabolic syndrome.
Br. J. Nutr.
2018,119, 1168–1176. [CrossRef] [PubMed]
Oikonomou, E.; Psaltopoulou, T.; Georgiopoulos, G.; Siasos, G.; Kokkou, E.; Antonopoulos, A.; Vogiatzi, G.;
Tsalamandris, S.; Gennimata, V.; Papanikolaou, A.; et al. Western Dietary Pattern Is Associated With Severe
Coronary Artery Disease. Angiology 2018,69, 339–346. [CrossRef]
Simopoulos, A.P.J.B. Pharmacotherapy. Evolutionary aspects of diet, the omega-6/omega-3 ratio and genetic
variation: Nutritional implications for chronic diseases. Biomed. Pharmacother.
,60, 502–507. [CrossRef]
Saini, R.K.; Keum, Y.-S. Omega-3 and omega-6 polyunsaturated fatty acids: Dietary sources, metabolism,
and signiﬁcance—A review. Life Sci. 2018,203, 255–267. [CrossRef]
Simopoulos, A. Essential fatty acids in health and chronic disease. Am. J. Clin. Nutr.
Simopoulos, A.P. Omega-3 fatty acids in health and disease and in growth and development. Am. J. Clin. Nutr.
1991,54, 438–463. [CrossRef] [PubMed]
Fedacko, J.; Vargova, V.; Singh, R.B.; Anjum, B.; Takahashi, T.; Tongnuka, M.; Dharwadkar, S.; Singh, S.;
Singh, V.; Kulshresth, S.K. Association of high w-6/w-3 fatty acid ratio diet with causes of death due to
noncommunicable diseases among urban decedents in North India. Open Nutr. J.
,5, 113–123. [CrossRef]
Salas-Salvadó, J.; Becerra-Tomás, N.; García-Gavilán, J.F.; Bulló, M.; Barrubés, L. Mediterranean Diet and
Cardiovascular Disease Prevention: What Do We Know? Prog. Cardiovasc. Dis.
,61, 62–67. [CrossRef]
Schulze, M.B.; Martínez-González, M.; Fung, T.T.; Lichtenstein, A.H.; Forouhi, N.G. Food based dietary
patterns and chronic disease prevention. BMJ 2018,361. [CrossRef] [PubMed]
Nutrients 2019,11, 301 11 of 14
Tsiouﬁs, C. The Mediterranean and the DASH dietary patterns: Insights into their role in cardiovascular
disease prevention. Hellenic. J. Cardiol. 2018,59, 134–135. [CrossRef]
Maddock, J.; Ziauddeen, N.; Ambrosini, G.L.; Wong, A.; Hardy, R.; Ray, S. Adherence to a Dietary Approaches
to Stop Hypertension (DASH)-type diet over the life course and associated vascular function: A study based
on the MRC 1946 British birth cohort. Br. J. Nutr. 2018,119, 581–589. [CrossRef] [PubMed]
Johnston, C.S.; Taylor, C.A.; Hampl, J.S. More Americans are eating “5 a day” but intakes of dark green and
cruciferous vegetables remain low. J. Nutr. 2000,130, 3063–3067. [CrossRef]
Lee-Kwan, S.H.; Moore, L.V.; Blanck, H.M.; Harris, D.M.; Galuska, D. Disparities in State-Speciﬁc Adult
Fruit and Vegetable Consumption—United States, 2015. MMWR 2017,66, 1241–1247. [CrossRef]
Adams, M.R.; Golden, D.L.; Chen, H.; Register, T.C.; Gugger, E.T. A diet rich in green and yellow vegetables
inhibits atherosclerosis in mice. Food Chem. 2006,136, 1886–1889. [CrossRef]
Chen, G.-C.; Koh, W.-P.; Yuan, J.-M.; Qin, L.-Q.; van Dam, R.M. Green leafy and cruciferous vegetable
consumption and risk of type 2 diabetes: Results from the Singapore Chinese Health Study and meta-analysis.
Br. J. Nutr. 2018,119, 1057–1067. [CrossRef]
Mori, N.; Shimazu, T.; Charvat, H.; Mutoh, M.; Sawada, N.; Iwasaki, M.; Yamaji, T.; Inoue, M.; Goto, A.;
Takachi, R.; et al. Cruciferous vegetable intake and mortality in middle-aged adults: A prospective cohort
study. Clin. Nutr. 2018, 1–13. [CrossRef] [PubMed]
Pollock, R.L. The effect of green leafy and cruciferous vegetable intake on the incidence of cardiovascular
disease: A meta-analysis. JRSM Cardiovasc. Dis. 2016,5, 1–9. [CrossRef] [PubMed]
Huang, Z.; Wang, B.; Eaves, D.; Shikany, J.; Pace, R. Phenolic compound proﬁle of selected vegetables
frequently consumed by African Americans in the southeast United States. Food Chem.
Huang, Z.; Wang, B.; Eaves, D.; Shikany, J.; Pace, R.D. Total phenolics and antioxidant capacity of indigenous
vegetables in the southeast United States: Alabama Collaboration for Cardiovascular Equality Project. Int. J.
Food Sci. Nutr. 2009,60, 100–108. [CrossRef] [PubMed]
Mohamed, A.I.; Hussein, A.S. Chemical composition of purslane (Portulaca oleracea). Plant Foods Hum. Nutr.
1994,45, 1–9. [CrossRef] [PubMed]
Petropoulos, S.A.; Karkanis, A.; Fernandes, A.; Barros, L.; Ferreira, I.C.; Ntatsi, G.; Petrotos, K.; Lykas, C.;
Khah, E. Chemical Composition and Yield of Six Genotypes of Common Purslane (Portulaca oleracea L.):
An Alternative Source of Omega-3 Fatty Acids. Plant Foods Hum. Nutr.
,70, 420–426. [CrossRef]
Almazan, A.M.; Begum, F.; Johnson, C. Nutritional quality of sweetpotato greens from greenhouse plants.
J. Food Compos. Anal. 1997,10, 246–253. [CrossRef]
Almazan, A.M.; Adeyeye, S.O. Fat and fatty acid concentrations in some green vegetables. J. Food
Compos. Anal. 1998,11, 375–380. [CrossRef]
Lin, L.-Z.; Harnly, J.M. Identiﬁcation of the Phenolic Components of Collard Greens, Kale, and Chinese
Broccoli. Agric. Food. Chem. 2009,57, 7401–7408. [CrossRef] [PubMed]
Johnson, M.; Pace, R. Sweet potato leaves: Properties and synergistic interactions that promote health and
prevent disease. Nutr. Rev. 2010,68, 604–615. [CrossRef] [PubMed]
Oduro, I.; Ellis, W.O.; Owusu, D. Nutritional potential of two leafy vegetables: Moringa oleifera and Ipomoea
batatas leaves. Sci. Res. Essay 2008,3, 57–60.
Joshipura, K.J.; Hu, F.B.; Manson, J.E.; Stampfer, M.J.; Rimm, E.B.; Speizer, F.E.; Colditz, G.; Ascherio, A.;
Rosner, B.; Spiegelman, D. The effect of fruit and vegetable intake on risk for coronary heart disease.
Ann. Intern. Med. 2001,134, 1106–1114. [CrossRef] [PubMed]
Blekkenhorst, L.C.; Bondonno, C.P.; Lewis, J.R.; Devine, A.; Zhu, K.; Lim, W.H.; Woodman, R.J.; Beilin, L.J.;
Prince, R.L.; Hodgson, J.M. Cruciferous and allium vegetable intakes are inversely associated with 15-year
atherosclerotic vascular disease deaths in older adult women. J. Am. Heart Assoc.
,6, e006558. [CrossRef]
Blekkenhorst, L.C.; Bondonno, C.P.; Lewis, J.R.; Woodman, R.J.; Devine, A.; Bondonno, N.P.; Lim, W.H.;
Zhu, K.; Beilin, L.J.; Thompson, P.L. Cruciferous and total vegetable intakes are inversely associated with
subclinical atherosclerosis in older adult women. J. Am. Heart Assoc.
,7, e008391. [CrossRef] [PubMed]
Nutrients 2019,11, 301 12 of 14
Duarte, J.; Pérez-Palencia, R.; Vargas, F.; Ocete, M.A.; Pérez-Vizcaino, F.; Zarzuelo, A.; Tamargo, J.
Antihypertensive effects of the ﬂavonoid quercetin in spontaneously hypertensive rats. Br. J. Pharmacol.
2001,133, 117–124. [CrossRef] [PubMed]
Edwards, R.L.; Lyon, T.; Litwin, S.E.; Rabovsky, A.; Symons, J.D.; Jalili, T. Quercetin reduces blood pressure
in hypertensive subjects. J. Nutr. 2007,137, 2405–2411. [CrossRef] [PubMed]
Larson, A.J.; Symons, J.D.; Jalili, T. Therapeutic Potential of Quercetin to Decrease Blood Pressure: Review of
Efﬁcacy and Mechanisms. Adv. Nutr. 2012,3, 39–46. [CrossRef]
Serban, M.C.; Sahebkar, A.; Zanchetti, A.; Mikhailidis, D.P.; Howard, G.; Antal, D.; Andrica, F.; Ahmed, A.;
Aronow, W.S.; Muntner, P. Effects of quercetin on blood pressure: A systematic review and meta-analysis of
randomized controlled trials. J. Am. Heart Assoc. 2016,5, e002713. [CrossRef]
Delgado, C.; Chertow, G.M.; Kaysen, G.A.; Dalrymple, L.S.; Kornak, J.; Grimes, B.; Johansen, K.L.
Associations of Body Mass Index and Body Fat With Markers of Inﬂammation and Nutrition Among
Patients Receiving Hemodialysis. Am. J. Kidney Dis. 2017,70, 817–825. [CrossRef]
Han, S.J.; Boyko, E.J.; Fujimoto, W.Y.; Kahn, S.E.; Leonetti, D.L. Low Plasma Adiponectin Concentrations
Predict Increases in Visceral Adiposity and Insulin Resistance. J. Clin. Endocrinol. Metab.
Peri-Okonny, P.; Ayers, C.; Maalouf, N.; Das, S.R.; de Lemos, J.A.; Berry, J.D.; Turer, A.T.; Neeland, I.J.;
Scherer, P.E.; Vongpatanasin, W. Adiponectin protects against incident hypertension independent of body fat
distribution: Observations from the Dallas Heart Study. Diabetes Metab. Res. Rev.
,33, e2840. [CrossRef]
Kyrou, I.; Tsantarlioti, O.; Panagiotakos, D.B.; Tsigos, C.; Georgousopoulou, E.; Chrysohoou, C.;
Skoumas, I.; Tousoulis, D.; Stefanadis, C.; Pitsavos, C. Adiponectin circulating levels and 10-year (2002–2012)
cardiovascular disease incidence: The ATTICA Study. Endocrine 2017,58, 542–552. [CrossRef] [PubMed]
Furuhashi, M.; Ura, N.; Higashiura, K.; Murakami, H.; Tanaka, M.; Moniwa, N.; Yoshida, D.; Shimamoto, K.
Blockade of the renin-angiotensin system increases adiponectin concentrations in patients with essential
hypertension. Hypertens 2003,42, 76–81. [CrossRef] [PubMed]
Cnop, M.; Havel, P.J.; Utzschneider, K.M.; Carr, D.B.; Sinha, M.K.; Boyko, E.J.; Retzlaff, B.M.; Knopp, R.H.;
Brunzell, J.D.; Kahn, S.E. Relationship of adiponectin to body fat distribution, insulin sensitivity and plasma
lipoproteins: Evidence for independent roles of age and sex. Diabetologia
,46, 459–469. [CrossRef]
Dehghan, F.; Soori, R.; Gholami, K.; Abolmaesoomi, M.; Yusof, A.; Muniandy, S.; Heidarzadeh, S.;
Farzanegi, P.; Ali azarbayjani, M. Purslane (Portulaca oleracea) Seed Consumption And Aerobic Training
Improves Biomarkers Associated with Atherosclerosis in Women with Type 2 Diabetes (T2D). Sci. Rep.
6, 37819. [CrossRef] [PubMed]
Nazeam, J.A.; El-Hefnawy, H.M.; Omran, G.; Singab, A.-N. Chemical proﬁle and antihyperlipidemic effect
of Portulaca oleracea L. seeds in streptozotocin-induced diabetic rats. Nat. Prod. Res.
Soori, R.; Shahedi, V.; Akbarnejad, A.; Choobineh, S. Biochemical changes in oxidative stress markers
following endurance training and consumption of purslane seed in rats with hydrogen peroxide-induced
toxicity. Sport Sci. Health 2018, 1–7. [CrossRef]
Hussein, M.A. Purslane extract effects on obesity-induced diabetic rats fed a high-fat diet. Malaysian J. Nutr.
Gray, B.; Steyn, F.; Davies, P.S.W.; Vitetta, L. Omega-3 fatty acids: A review of the effects on adiponectin and
leptin and potential implications for obesity management. Eur. J. Clin. Nutr.
,67, 1234–1242. [CrossRef]
DeClercq, V.; d
Eon, B.; McLeod, R.S. Fatty acids increase adiponectin secretion through both classical and
exosome pathways. Biochim. Biophys. Acta Mol. Cell. Biol. Lipids 2015,1851, 1123–1133. [CrossRef]
Simopoulos, A. An Increase in the Omega-6/Omega-3 Fatty Acid Ratio Increases the Risk for Obesity.
Nutrients 2016,8, 128. [CrossRef] [PubMed]
Hu, E.; Liang, P.; Spiegelman, B.M. AdipoQ Is a Novel Adipose-speciﬁc Gene Dysregulated in Obesity.
J. Biol. Chem. 1996,271, 10697–10703. [CrossRef] [PubMed]
Asayama, K.; Hayashibe, H.; Dobashi, K.; Uchida, N.; Nakane, T.; Kodera, K.; Shirahata, A.; Taniyama, M.
Decrease in serum adiponectin level due to obesity and visceral fat accumulation in children. Obes. Res.
2003,11, 1072–1079. [CrossRef]
Nutrients 2019,11, 301 13 of 14
Fontana, L.; Eagon, J.C.; Trujillo, M.E.; Scherer, P.E.; Klein, S. Visceral fat adipokine secretion is associated
with systemic inﬂammation in obese humans. Diabetes 2007,56, 1010–1013. [CrossRef] [PubMed]
Esposito, K.; Nappo, F.; Giugliano, F.; Di Palo, C.; Ciotola, M.; Barbieri, M.; Paolisso, G.; Giugliano, D. Meal
modulation of circulating interleukin 18 and adiponectin concentrations in healthy subjects and in patients
with type 2 diabetes mellitus. Am. J. Clin. Nutr. 2003,78, 1135–1140. [CrossRef] [PubMed]
Pischon, T.; Girman, C.J.; Rifai, N.; Hotamisligil, G.S.; Rimm, E.B. Association between dietary factors and
plasma adiponectin concentrations in men. Am. J. Clin. Nutr. 2005,81, 780–786. [CrossRef] [PubMed]
Peake, P.W.; Kriketos, A.D.; Denyer, G.S.; Campbell, L.V.; Charlesworth, J.A. The postprandial response
of adiponectin to a high-fat meal in normal and insulin-resistant subjects. Int. J. Obes.
Lithander, F.E.; Keogh, G.F.; Wang, Y.; Cooper, G.J.S.; Mulvey, T.B.; Chan, Y.-K.; McArdle, B.H.; Poppitt, S.D.
No evidence of an effect of alterations in dietary fatty acids on fasting adiponectin over 3 weeks. Obesity
2008,16, 592–599. [CrossRef]
Huang, T.; Tobias, D.K.; Hruby, A.; Rifai, N.; Tworoger, S.S.; Hu, F.B. An Increase in Dietary Quality Is
Associated with Favorable Plasma Biomarkers of the Brain-Adipose Axis in Apparently Healthy US Women.
J. Nutr. 2016,146, 1101–1108. [CrossRef]
Suzuki, K.; Inoue, T.; Hashimoto, S.; Ochiai, J.; Kusuhara, Y.; Ito, Y.; Hamajima, N.J. Association of serum
carotenoids with high molecular weight adiponectin and inﬂammation markers among Japanese subjects.
Clin. Chim. Acta 2010,411, 1330–1334. [CrossRef]
Saura-Calixto, F. Dietary ﬁber as a carrier of dietary antioxidants: An essential physiological function. J. Agric.
Food Chem. 2010,59, 43–49. [CrossRef] [PubMed]
Ntalla, I.; Dedoussis, G.; Yannakoulia, M.; Smart, M.C.; Louizou, E.; Sakka, S.D.; Papoutsakis, C.; Talmud, P.
ADIPOQ gene polymorphism rs1501299 interacts with ﬁbre intake to affect adiponectin concentration in
children: The GENe–Diet Attica Investigation on childhood obesity. Eur. J. Nutr.
,48, 493. [CrossRef]
Hermsdorff, H.H.M.; Puchau, B.; Volp, A.C.P.; Barbosa, K.B.F.; Bressan, J.; Zulet, M.Á.; Martínez, J.A. Dietary
total antioxidant capacity is inversely related to central adiposity as well as to metabolic and oxidative stress
markers in healthy young adults. Nutr. Metab. 2011,8, 59. [CrossRef] [PubMed]
Devaraj, S.; Torok, N.; Dasu, M.R.; Samols, D.; Jialal, I. Adiponectin decreases C-reactive protein synthesis
and secretion from endothelial cells: Evidence for an adipose tissue-vascular loop. Arterioscler. Thromb.
Vasc. Biol. 2008,28, 1368–1374. [CrossRef] [PubMed]
Detopoulou, P.; Panagiotakos, D.; Chrysohoou, C.; Fragopoulou, E.; Nomikos, T.; Antonopoulou, S.;
Pitsavos, C.; Stefanadis, C. Dietary antioxidant capacity and concentration of adiponectin in apparently
healthy adults: The ATTICA study. Eur. J. Clin. Nutr. 2010,64, 161. [CrossRef] [PubMed]
Franzini, L.; Ardigo, D.; Valtuena, S.; Pellegrini, N.; Del Rio, D.; Bianchi, M.; Scazzina, F.; Piatti, P.; Brighenti, F.;
Zavaroni, I. Food selection based on high total antioxidant capacity improves endothelial function in a low
cardiovascular risk population. Nutr. Metab. Cardiovasc. Dis. 2012,22, 50–57. [CrossRef]
67. Kamigaki, M.; Sakaue, S.; Tsujino, I.; Ohira, H.; Ikeda, D.; Itoh, N.; Ishimaru, S.; Ohtsuka, Y.; Nishimura, M.
Oxidative stress provokes atherogenic changes in adipokine gene expression in 3T3-L1 adipocytes.
Biochem. Biophys. Res. Commun. 2006,339, 624–632. [CrossRef]
D’Archivio, M.; Filesi, C.; Di Benedetto, R.; Gargiulo, R.; Giovannini, C.; Masella, R. Polyphenols, dietary
sources and bioavailability. Ann. Ist. Super Sanità2007,43, 348.
D’Archivio, M.; Filesi, C.; Varì, R.; Scazzocchio, B.; Masella, R. Bioavailability of the polyphenols: Status and
controversies. Int. J. Mol. Sci. 2010,11, 1321–1342. [CrossRef]
Kahlon, T.; Chapman, M.; Smith, G.
binding of bile acids by spinach, kale, brussels sprouts, broccoli,
mustard greens, green bell pepper, cabbage and collards. Food Chem. 2007,100, 1531–1536. [CrossRef]
Kahlon, T.S.; Chiu, M.-C.M.; Chapman, M.H. Steam cooking signiﬁcantly improves
bile acid binding
of collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage. Nutr. Res.
Innami, S.; Tabata, K.; Shimizu, J.; Kusunoki, K.; Ishida, H.; Matsuguma, M.; Wada, M.; Sugiyama, N.;
Kondo, M. Dried green leaf powders of Jew‘s mellow (Corchorus), persimmon (Diosphyros kaki) and sweet
potato (Ipomoea batatas poir) lower hepatic cholesterol concentration and increase fecal bile acid excretion
in rats fed a cholesterol-free diet. Plant Foods Hum. Nutr. 1998,52, 55–66. [CrossRef] [PubMed]
Nutrients 2019,11, 301 14 of 14
Sadakane, A.; Tsutsumi, A.; Gotoh, T.; Ishikawa, S.; Ojima, T.; Kario, K.; Nakamura, Y.; Kayaba, K. Dietary
patterns and levels of blood pressure and serum lipidsin a japanese population. J. Epiddemiol.
Gallaher, D.D.; Hassel, C.A.; Lee, K.-J.; Gallaher, C.M. Viscosity and fermentability as attributes of dietary
ﬁber responsible for the hypocholesterolemic effect in hamsters. J. Nutr. 1993,123, 244–252. [PubMed]
Brown, L.; Rosner, B.; Willett, W.W.; Sacks, F.M. Cholesterol-lowering effects of dietary ﬁber: A meta-analysis.
Am. J. Clin. Nutr. 1999,69, 30–42. [CrossRef] [PubMed]
Estruch, R.; Martínez-González, M.A.; Corella Piquer, D.; Basora-Gallisá, J.; Ruiz-Gutiérrez, V.; Covas
Planells, M.I.; Fiol Sala, M.; Gómez Gracia, E.; López Sabater, M.C. Effects of dietary ﬁbre intake on risk
factors for cardiovascular disease in subjects at high risk. J. Epidemiol. Community Health
Anderson, J.W.; Baird, P.; Davis, R.H.; Ferreri, S.; Knudtson, M.; Koraym, A.; Waters, V.; Williams, C.L. Health
beneﬁts of dietary ﬁber. Nutr. Rev. 2009,67, 188–205. [CrossRef]
Jacobs, D.R., Jr.; Mebane, I.L.; Bangdiwala, S.I.; Criqui, M.H.; Tyroler, H.A. High density lipoprotein
cholesterol as a predictor of cardiovascular disease mortality in men and women: The follow-up study of the
Lipid Research Clinics Prevalence Study. Am. J. Epidemiol. 1990,131, 32–47. [CrossRef]
Johnson, M.; Pace, R.D.; McElhenney, W. Green leafy vegetables in diets with a 25:1 omega-6/omega-3 fatty
acid ratio modify the erythrocyte fatty acid proﬁle of spontaneously hypertensive rats. Lipids Health Dis.
2018,17, 140. [CrossRef]
Balk, E.; Lichtenstein, A.H.; Chung, M.; Kupelnick, B.; Chew, P.; Lau, J. Effects of omega-3 fatty acids
on serum markers of cardiovascular disease risk: A systematic review. Atherosclerosis
Harris, W.S.; Miller, M.; Tighe, A.P.; Davidson, M.H.; Schaefer, E.J. Omega-3 fatty acids and coronary heart
disease risk: Clinical and mechanistic perspectives. Atherosclerosis 2008,197, 12–24. [CrossRef] [PubMed]
Lundberg, J.O.; Carlström, M.; Weitzberg, E. Metabolic effects of dietary nitrate in health and disease.
Cell Metab. 2018,28, 9–22. [CrossRef] [PubMed]
van Breda, S.G.J.; de Kok, T.M.C.M. Smart Combinations of Bioactive Compounds in Fruits and Vegetables
May Guide New Strategies for Personalized Prevention of Chronic Diseases. Mol. Nutr. Food Res.
62, 1700597. [CrossRef] [PubMed]
Hadi, A.; Pourmasoumi, M.; Najafgholizadeh, A.; Kafeshani, M.; Sahebkar, A. Effect of purslane on blood
lipids and glucose: A systematic review and meta-analysis of randomized controlled trials. Phytother. Res.
2019,33, 3–12. [CrossRef] [PubMed]
Sun, H.; Mu, B.; Song, Z.; Ma, Z.; Mu, T. The In Vitro Antioxidant Activity and Inhibition of Intracellular
Reactive Oxygen Species of Sweet Potato Leaf Polyphenols. Oxid. Med. Cell Longev.
Mozaffarian, D.; Wu, J.H.Y. Omega-3 Fatty Acids and Cardiovascular Disease: Effects on Risk Factors,
Molecular Pathways, and Clinical Events. J. Am. Coll. Cardiol. 2011,58, 2047–2067. [CrossRef]
Trayhurn, P.; Wood, I.S. Adipokines: Inﬂammation and the pleiotropic role of white adipose tissue.
Br. J. Nutr.
2004,92, 347–355. [CrossRef]
2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution
(CC BY) license (http://creativecommons.org/licenses/by/4.0/).