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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

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The typical Western dietary pattern has an elevated ω-6:ω-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 ω-6:ω-3 FAR. Male spontaneously hypertensive rats (SHRs) were randomly assigned to four dietary groups (n = 10/group) with a 25:1 ω-6:ω-3 FAR. 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.
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nutrients
Article
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
1
College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL 36088, USA
2
Department of Agricultural and Environmental Sciences, College of Agriculture, Environment and Nutrition
Sciences, Tuskegee University, Tuskegee, AL 36088, USA; wmcelhenney@tuskegee.edu (W.H.M.);
megnin@tuskegee.edu (M.E.)
*Correspondence: mjohnson3@tuskegee.edu; Tel.: +1-334-727-8625
Received: 12 December 2018; Accepted: 25 January 2019; Published: 31 January 2019


Abstract:
The typical Western dietary pattern has an elevated
ω
-6:
ω
-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
ω
-6:
ω
-3 FAR. Male spontaneously hypertensive rats
(SHRs) were randomly assigned to four dietary groups (n= 10/group) with a 25:1
ω
-6:
ω
-3 FAR.
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.
Keywords:
collard greens; purslane; sweetpotato greens;
ω
-6:
ω
-3 fatty acid ratio; cardiovascular
disease; spontaneously hypertensive rat
1. Introduction
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 [
1
]. 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 [
2
7
]. Diets rich in omega-6 (
ω
-6) fatty
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 [
8
,
9
]. The current
ω
-6/
ω
-3
FAR within the Western diet is estimated to be approximately 25:1 [
10
,
11
]. This imbalance in the
ω
-6/
ω
-3 FAR, coupled with traditional Western dietary practices, further exacerbates the increased
risk for hypertension and other CVDs [12].
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 [
13
16
]. Although Americans consume less than recommended
intakes [17,18]
, 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 [
19
22
]. 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 [
23
,
24
].
The nutritional profile of collard greens, purslane and orange flesh sweetpotato greens suggest their
potential functionality in disease prevention and health promotion [2531].
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
in vivo
, 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
ω
-6/
ω
-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
may emerge.
2. Materials and Methods
2.1. Dietary Formulations
The American Institute of Nutrition (AIN)-76A purified rodent diet was modified to a final
ω
-6/
ω
-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
Fish Oil
Cholesterol 0.07 0.07 0.07 0.07
Collard Greens 4.00
Purslane 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
80
C
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
µ
Moles of TroloxTM Equivalents (TE) were calculated based on the
TroloxTM antioxidant standard curve. The area under the curve (AUC) was calculated using the
following equation
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
®
Inc.,
Cambridge, MA, USA), HDL-C (Abcam
®
Inc., Cambridge, MA, USA) and LDL-C + VLDL-C
(Abcam
®
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. Results
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
ω
-6/
ω
-3 FAR were heavier
(p< 0.05) than those consuming the AIN-76A diet.
Table 3. SHR dietary intake and body weight.
Dietary
Group
Initial Dietary
Intake (g)
Final Dietary
Intake (g)
Total Dietary
Intake (g)
Baseline
Weight (g)
Initial Body
Weight (g)
Final Body
Weight (g)
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).
100
110
120
130
140
150
160
170
180
190
Systolic Blood Pressure (mmHg)
AIN-76A
25:1 C
25:1 CG
25:1 PL
25:1 SPG
*
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
µ
g/mL) diet versus
those consuming the AIN-76A (43.0
µ
g/mL) and C (38.6
µ
g/mL) diets. Although not statistically
significant, plasma adiponectin levels were reduced among SHRs assigned to the CG (35.1
µ
g/mL)
Nutrients 2019,11, 301 6 of 14
and SPG (31.5
µ
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
µ
g/mL)
followed by those consuming the C diet (1092.2
µ
g/mL). Diets containing CG (1164.0
µ
g/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 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
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).
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
a
97.0 ± 4.2
c
92.2 ± 7.3
c
113.0 ± 4.0
bc
118.4 ± 12.6
b
TC (mg/dL) 75.5 ± 11.8
a
64.1 ± 2.8
a
62.5 ± 3.1
a
61.6 ± 2.5
a
58.0 ± 2.3
a
HDL-C (mg/dL) 39.2 ± 2.5
a
33.7 ± 2.6
a
38.7 ± 1.9
a
41.3 ± 1.3
a
19.4 ± 6.6
b
LDL-C + VLDL-C (mg/dL) 10.5 ± 3.6
a
15.1 ± 1.2
a
12.6 ± 1.5
a
10.5 ± 0.6
a
11.2 ± 0.98
a
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).
4. Discussion
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
0
1
2
3
4
5
6
7
8
9
10
AIN-76A 25:1 C 25:1 CG 25:1 PL 25:1 SPG
ORAC Value mMole Trolox Equivalents (TE)
Dietary Group
AIN-76A
25:1 C
25:1 CG
25:1 PL
25:1 SPG
a
a
b b b
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.
Nutrients 2019,11, 301 7 of 14
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 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).
4. Discussion
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 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 [
32
34
]. 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 [3538].
Levels of adiponectin, an adipose-specific protein, are inversely associated with levels of
adiposity [
39
]. Consequently, lower levels of adiponectin are linked to increased risk for obesity,
insulin resistance, diabetes, cardiovascular and other diseases [
40
42
]. Increases in plasma adiponectin
concentrations have been observed with the obstruction of the renin-angiotensin system [
43
], increased
HDL concentrations, and decreased body mass index [
44
]. 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 [
45
]. Additionally, purslane has been
demonstrated to reduce the risks associated with oxidative stress, cardiovascular disease and other
diseases [
46
,
47
]. In a study by Hussein purslane extract incorporated into a high-fat diet was able to
inhibit weight gain and improve insulin resistance [
48
]. 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
intake [49,50]
.
Furthermore, it has been suggested that the risk for obesity increases with an increase in the
omega-6/omega-3 fatty acid ratio [51]. 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 [
52
54
].
While decreases in plasma adiponectin concentrations have been reported with increased dietary
fat [
55
], others have reported plasma adiponectin concentrations to be positively associated with total
dietary fat intake [
56
]; high fat intakes have also been reported to exert no influence on adiponectin
concentrations [
57
,
58
]. 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 [
59
].
Increased consumption of fruits and vegetables, rich plant sources of dietary antioxidants, have
been connected with increased antioxidant concentrations associated with increased adiponectin
concentrations [
60
] 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 [
61
]. 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 [
62
]. 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) [
63
]. 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 [
64
]. Research indicates higher dietary antioxidant capacities to be positively
associated with increased adiponectin levels [
65
] and decreased CRP levels [
66
]. Higher levels of
(dietary) antioxidants are believed to indirectly increase adiponectin concentrations by decreasing
oxidative stress, which reduces the expression of adiponectin [
67
]. 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
in vitro
,
the influence of which was significantly enhanced following steam cooking [
70
,
71
]. 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
cholesterol [
72
]. 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 [
73
,
74
]. 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 [
75
]. 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
diseases [
76
,
77
]. 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
mortality [
78
]. Other research has revealed the ability of CG, PL and SPG to influence the erythrocyte
fatty acid profile of spontaneously hypertensive rats [79].
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 [
80
]. 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 [
81
]. However, many of these mechanisms
remain unclear.
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 [
82
],
phytochemicals [
83
], flavonoids [
84
], polyphenols [
85
] and omega-3 fatty acids [
86
], 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 [
87
].
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.
5. Conclusions
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
ω
-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
ω
-6:
ω
-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
ω
-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
ω
-6:
ω
-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.
Author Contributions:
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.
Funding:
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.
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... Scientific investigations have also reported the antimicrobial, anti-inflammatory, anticancer, analgesic, antioxidant, and antidiabetic activities of CG [1,[21][22][23][24][25][26]. Compounds such as quercetin, catechins, dihydroquercetin, and rutin are reported to be excellent sources of natural antioxidants in most green leafy vegetables, including spinach, kale, collard greens, lettuce, purslane, amaranthus, and sweet potato greens [27,28]. ...
... Specifically, in the DPPH assay, the extracts efficacy and specific RC50 values for the accessions ranged between 137. 27 The estimation of the dose required scavenging fifty percent of radicals (RC 50 ), and concentration was determined using results for graded series of sample concentrations; the results are summarized in Table 2. The lowest average RC 50 value (396.71 ± 3.60 µg/mL) was recorded in the siliques, and the highest average value (1427.09 ...
... Specifically, in the DPPH assay, the extracts efficacy and specific RC 50 values for the accessions ranged between 137. 27 Data are presented as means ± standard deviation, n = 3, for each organ in each accession. The antioxidant activity was expressed as RC 50 values, meaning that a higher value corresponds to lower antioxidant potential. ...
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The presence of nutritional and health-benefiting compounds has increased awareness of orphan leafy vegetables such as Cleome gynandra (CG), whose phytochemicals vary among accessions and organs during growth. This study investigated the polyphenol accumulation and antioxidant activities (AOA) of eight CG accessions from the vegetative stage to the seed set stage. Plants were separated into leaves and stem (LS), flowers, and silique organs, and extracts were analyzed for total phenolic content (TPC), total flavonoid content (TFC), rutin and astragalin content, and AOA using 2,2-diphenyl-1-picrylhydrazyl-hydrate (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). There were significant interaction effects of growth stages and accessions that contributed to changes in compounds content and AOA. TPC accumulated in plant generative parts, whereas flavonoids accumulated in young plant organs. HPLC profiling revealed that rutin was the most abundant compound in all organs, with flowers having the highest levels, while astragalin was only found in flowers. Silique extracts, particularly accession KF-14, recorded the highest TPC, which corresponded to the strongest radical scavenging activity in ABTS and DPPH assays and a strong linear correlation. The germplasm contained accessions with significantly different and varying levels of bioactive compounds and AOA. These findings potentiate the exploitation of CG organs such as siliques for AOA, flowers for rutin and astragalin, and young shoots for flavonoids. Moreover, the significant accumulation of the compounds in particular accessions of the germplasms suggest that such superior accessions may be useful candidates in genetic breeding programs to improve CG vegetable.
... The main compounds detected are as follows: a-linolenic, oleic, and linoleic acids (53.55, 22.55, and 12.83%, respectively). PUFAs can act as antioxidants by reducing lipid peroxides and play a role in regulating oxidative stress by increasing the lipid peroxidation-induced oxidative charge and activating antioxidant enzymes (52). It is also known that these molecules are involved in the regulation of redox balance, cardiovascular and hormonal activities, blood pressure and renal function. ...
... It is also known that these molecules are involved in the regulation of redox balance, cardiovascular and hormonal activities, blood pressure and renal function. These molecules also have many effects on platelet aggregation, anti-inflammatory and antioxidant properties (38,52) ...
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The aims of this study are to investigate the preventive effect of flaxseed oil (FO) on bleo-mycin (BLM)-induced pulmonary fibrosis (PF). Thirty adult male Wistar rats (180-220 g) were randomly divided into three groups. The control group (G 1) received no treatment, the group (G 2) received only intratracheally BLM, and the group (G 3) received FO (2 mL/kg body weight) once a day for 60 days þ BLM (4 mg/kg body weight "bw"). Our results demonstrated that FO protected against BLM-induced PF, by increasing proline, fructose, glucose, glyceride, choline, lactate, and malate metabolites in bronchoalveolar lavage fluid (Balf) which are involved in anti-inflammatory reactions. Also, FO-treatment reduced the score of fibrosis and the inflammatory index and revealed a decrease in tumor growth factor beta (TGFb) density in alveoli, inflammatory infiltrate and fibrocytes, comparatively to the BLM group. As well, our data demonstrated that acute BLM-induced fibrosis was accompanied by an oxidative stress in lung tissue as assessed by an increase of lipid peroxidation as well as antioxidant enzyme activities depletion such as superoxide dismutase (SOD) and catalase (CAT). The FO treatment reversed all disturbances of BLM-induced oxidative stress parameters , and increased fatty acids levels promoting anti-inflammatory reactions especially in erythrocytes (linoleic, a-linolenic, docosapentaenoic acids). ARTICLE HISTORY
... Nutraceuticals are chemical compounds present in foods that exert pharmacological activity, resulting in the prevention and treatment of chronic diseases [11]. Glucosinolates, carotenoids, and phenolic compounds from kale are health-related secondary metabolites associated with several beneficial characteristics, showing various pharmacological effects correlated to their antioxidant activity [12,13]. The main biological activities related to kale are antioxidant, anti-cancerogenic, and protective effects on the cardiovascular and gastrointestinal tract [4,12,14,15]. ...
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Kale (Brassica oleracea L. var. acephala DC) is a popular cruciferous vegetable originating from Central Asia, and is well known for its abundant bioactive compounds. This review discusses the main kale phytochemicals and emphasizes molecules of nutraceutical interest, including phenolics, carotenoids, and glucosinolates. The preventive and therapeutic properties of kale against chronic and degenerative diseases are highlighted according to the most recent in vitro, in vivo, and clinical studies reported. Likewise, it is well known that the application of controlled abiotic stresses can be used as an effective tool to increase the content of phytochemicals with health-promoting properties. In this context, the effect of different abiotic stresses (saline, exogenous phytohormones, drought, temperature, and radiation) on the accumulation of secondary metabolites in kale is also presented. The information reviewed in this article can be used as a starting point to further validate through bioassays the effects of abiotically stressed kale on the prevention and treatment of chronic and degenerative diseases.
... 26 Another study that assessed the effects of olive-leaf extracted polyphenols for 14 weeks reported beneficial effects on fasting insulin levels, consistent with our results. This finding could be explained by the increased fibre content in the green MED diet, 27 probably derived from Mankai. The reduction in insulin resistance demonstrated here also corresponds with our recent report about the beneficial acute glycaemic response to Mankai compared with yoghurt shake 28 and might suggest that regular consumption of Mankai improves short-term glucose tolerance, and also promotes long-term improvement in sensitivity to insulin. ...
... An experimental study on hypertensive rats fed collard greens or other vegetables found that they had a significant reduction in blood pressure with respect to their counterparts [26]. ...
... 26 Another study that assessed the effects of olive-leaf extracted polyphenols for 14 weeks reported beneficial effects on fasting insulin levels, consistent with our results. This finding could be explained by the increased fibre content in the green MED diet, 27 probably derived from Mankai. The reduction in insulin resistance demonstrated here also corresponds with our recent report about the beneficial acute glycaemic response to Mankai compared with yoghurt shake 28 and might suggest that regular consumption of Mankai improves short-term glucose tolerance, and also promotes long-term improvement in sensitivity to insulin. ...
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Background A Mediterranean diet is favourable for cardiometabolic risk. Objective To examine the residual effect of a green Mediterranean diet, further enriched with green plant-based foods and lower meat intake, on cardiometabolic risk. Methods For the DIRECT-PLUS parallel, randomised clinical trial we assigned individuals with abdominal obesity/dyslipidaemia 1:1:1 into three diet groups: healthy dietary guidance (HDG), Mediterranean and green Mediterranean diet, all combined with physical activity. The Mediterranean diets were equally energy restricted and included 28 g/day walnuts. The green Mediterranean diet further included green tea (3–4 cups/day) and a Wolffia globosa (Mankai strain; 100 g/day frozen cubes) plant-based protein shake, which partially substituted animal protein. We examined the effect of the 6-month dietary induction weight loss phase on cardiometabolic state. Results Participants (n=294; age 51 years; body mass index 31.3 kg/m ² ; waist circumference 109.7 cm; 88% men; 10 year Framingham risk score 4.7%) had a 6-month retention rate of 98.3%. Both Mediterranean diets achieved similar weight loss ((green Mediterranean −6.2 kg; Mediterranean −5.4 kg) vs the HDG group −1.5 kg; p<0.001), but the green Mediterranean group had a greater reduction in waist circumference (−8.6 cm) than the Mediterranean (−6.8 cm; p=0.033) and HDG (−4.3 cm; p<0.001) groups. Stratification by gender showed that these differences were significant only among men. Within 6 months the green Mediterranean group achieved greater decrease in low-density lipoprotein cholesterol (LDL-C; green Mediterranean −6.1 mg/dL (−3.7%), −2.3 (-0.8%), HDG −0.2 mg/dL (+1.8%); p=0.012 between extreme groups), diastolic blood pressure (green Mediterranean −7.2 mm Hg, Mediterranean −5.2 mm Hg, HDG −3.4 mm Hg; p=0.005 between extreme groups), and homeostatic model assessment for insulin resistance (green Mediterranean −0.77, Mediterranean −0.46, HDG −0.27; p=0.020 between extreme groups). The LDL-C/high-density lipoprotein cholesterol (HDL-C) ratio decline was greater in the green Mediterranean group (−0.38) than in the Mediterranean (−0.21; p=0.021) and HDG (−0.14; p<0.001) groups. High-sensitivity C-reactive protein reduction was greater in the green Mediterranean group (−0.52 mg/L) than in the Mediterranean (−0.24 mg/L; p=0.023) and HDG (−0.15 mg/L; p=0.044) groups. The green Mediterranean group achieved a better improvement (−3.7% absolute risk reduction) in the 10-year Framingham Risk Score (Mediterranean−2.3%; p = 0.073, HDG−1.4%; p<0.001). Conclusions The green MED diet, supplemented with walnuts, green tea and Mankai and lower in meat/poultry, may amplify the beneficial cardiometabolic effects of Mediterranean diet. Trial registration number This study is registered under ClinicalTrials.gov Identifier no NCT03020186 .
... Researchers have reported that, ω-3, 6, fatty acids are very important to patients surviving from myocardial, cardiovascular disease (Dunbar et al., 2014) and anti-inflammatory effects, positive effect on obesity, improved endothelial function, reduced blood pressure, lowered triglycerides in blood (Patterson et al., 2012), for alteration of chemotherapeutic drugs toxicity, protection from skin and oral cancers (M. Johnson et al., 2019). Calder (2015) has reported that, n-3 PUFA are very important in immunomodulatory and antiinflammatory properties. ...
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There has been an increasing trend in recent times for taking more of green leafy vegetables (GLV) portion in the human diet. Among various GLVs available for human consumption, some are confined to a specific region and few are available in many parts of the world. Kale (Brassica oleracea L. var. acephala) is among the latter group which belongs to Brassicaceae family. This review summarizes the nutritional composition and anti-nutritional factors of kale available in different parts of the world. Consideration was also given for summarization of the studies reported on health benefits, pharmacological activities and different food products. It is noted from the literature that kale is a good source of fiber and minerals like potassium with higher calcium bioavailability than that of milk. Kale also contains prebiotic carbohydrates, unsaturated fatty acids and different vitamins while the anti-nutritional factors such as oxalates, tannins and phytate are present in higher concentrations. Research studies are reported different health beneficial activities of the kale like protective role in coronary artery disease, Anti-inflammatory activity, Antigenotoxic ability, gastro protective activity , inhibition of the carcinogenic compounds formation, positive to gut microbes, anti-Neela Satheesh
... 27 Interestingly, because of homeostasis, increased intake of n-3 or n-6 does not significantly affect the amount of metabolites produced or the secretion of downstream inflammatory markers. [32][33][34][35][36][37] ...
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Background and objective: Severe chronic obstructive pulmonary disease (COPD) is the terminal stage of the disease characterized by declined lung function, malnutrition, and poor prognosis. Such patients cannot tolerate long-time sports rehabilitation owing to dyspnea and fail to achieve the desired therapeutic effect; therefore, increasing nutritional support will be an important strategy for them. The present study applied metabolomics technology to evaluate the correlation between serum concentrations of polyunsaturated fatty acid (PUFA) metabolites, nutritional status, and lung function in patients with COPD to provide a theoretical basis for accurate nutritional support. Materials and methods: We enrolled 82 patients with stable severe COPD in our hospital. The general characteristics including height, weight, and lung function were recorded. Metabolomics was used to detect the concentrations of serum metabolites of n-3 and n-6 at baseline and at 24 and 52 weeks after enrollment. The correlations between nutrition level and pulmonary function and clinical indicators were evaluated. Results: The concentrations of n-3 and n-6 increased over time along with the progression of COPD. Body mass index (BMI) and percent of ideal body weight (IBW%) decreased with disease development, and BMI was found to be significantly correlated with FEV1% predicted and FEV1/FVC. Serum levels of n-6 metabolites such as linoleic acid (LA), γ-linoleic acid (GLA), and arachidonic acid (ARA) (all P < 0.01) and the n-3 metabolites such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (all P < 0.05) showed significant correlations with BMI and were closely correlated with FEV1% predicted and FEV1/FVC of lung function (all P< 0.05). Conclusion: This study demonstrates that malnutrition in patients with severe COPD is progressive and is positively correlated with n-3 and n-6 polyunsaturated fatty acids and lung function.
... Consumption of green leafy vegetables has been growing in response to the emergent number of degenerative diseases (Johnson et al. 2019). Increasing evidence has shown that ingestion of fresh products can decrease the risk of cancer and cardiovascular disorders (FAO 2019). ...
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The objective of this study was to evaluate the impact of different mixtures of two fresh-cut baby lettuce (Lactuca sativa L. var. crispa cv. Lollo Bionda [LB] and cv. Lollo Rossa [LR]) cultivars on lettuce phytochemical composition during postharvest. Lettuces were grown in a soilless culture system with continuous flotation (FL) in a greenhouse, mixed at harvest and packaged in polypropylene bags and stored at 4 °C for 9 days (d9). Mixes were made of 100, 75, 50, 25 and 0% of LB, respectively. The results showed that the phytochemicals were preserved during storage. In specific, 25LB had the highest pigment content on d1, while 50LB and 25LB had the highest inherent quality on d1.FL led to a reduced microbial contamination, thus, limiting its growth during storage. The results have revealed that high quality and microbiologically safe baby leaf vegetables (BLV), can be obtained by means of FL. The adopting a mix of lettuce cultivars could represent a positive postharvest practice to preserve the phytochemicals of BLV throughout their shelf life.
Article
Background and Aims Results of in vitro and in vivo studies showed that green leafy vegetables (GLV) could attenuate liver steatosis. However, little is known regarding the association between GLV intake and nonalcoholic fatty liver disease (NAFLD) in human. We examined the association of GLV intake with NAFLD in a large-scale adult population. Methods and Results This cross-sectional study investigated 26,891 adults in China who participated in health examinations from 2013 to 2017. Newly diagnosed NAFLD was detected by liver ultrasonography. Dietary intake was assessed by using a validated and standardized food frequency questionnaire. Multivariable logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) across categories of GLV intake. After adjustment for sociodemographic characteristics, lifestyle factors, and other dietary intakes, the OR (95% CI) for comparing the highest vs. lowest GLV intake categories (≥7 times/week vs. almost never) was 0.72 (0.59, 0.90) (P <0.0001). In addition, a linear inverse association was demonstrated between GLV intake and NAFLD in women (P for trend = 0.04), but ORs for any intake category did not reach significance. Stratified analyses suggested a potential effect modification by obesity status; the ORs (95% CIs) for comparing the highest vs. lowest GLV intake categories was 0.72 (0.54, 0.97) in normal/overweight individuals and 1.04 (0.65, 1.65) in obese individuals (P-interaction < 0.0001). Conclusion This large population-based study shows that high GLV intake is inversely associated with NAFLD, particularly in women and non-obese participants.
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The current study examined fluctuations in oxidative stress markers following endurance training (ET) and consumption of purslane seeds (Ps) in rats after receiving H2O2. Fifty-four adult male Wistar rats were assigned to nine experimental groups: (1) control (intoxicated-no treatment); (2) ET; (3) ET + Ps 50 mg/kg/day; (4) ET + Ps 200 mg/kg/day; (5) ET + Ps 400 mg/kg/day; (6) Ps 50 mg/kg/day; (7) Ps 200 mg/kg/day; (8) Ps 400 mg/kg/day; (9) control (non-intoxicated, intact). The first eight groups were given 100 mg/kg of H2O2 to induce oxidative stress. Groups 2–5 were given ET for a period of 8 weeks. Heart and lung tissues were then exposed to evaluate the oxidative stress markers. Catalase, glutathione peroxidase, malondialdehyde, and superoxide dismutase enzymes were measured using ELISA kits. A marked improvement in enzyme concentration was observed in both tissues. It was more pronounced in the groups receiving higher doses of Ps + ET. The findings provide evidence that purslane seed supplementation has antioxidant potential alongside endurance training and improved the ability to cope with oxidative stress.
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Background: In addition to the actual composition of the diet (i.e. nutrient composition, food groups), the omega-6/omega-3 fatty acid ratio has been demonstrated to influence the tissue fatty acid profile and subsequently the risk for cardiovascular and other diseases. Likewise, the consumption of green leafy vegetables (GLVs) may favorably reduce the risks associated with disease. Although an ~ 3:1 omega-6/omega-3 fatty acid ratio (ω-6/ω-3 FAR) is recommended, the typical American diet has an ~ 25:1 ω-6/ω-3 FAR. Previous research affirms the ability of collard greens (CG), purslane (PL), and sweet potato greens (SPG) to improve the hepatic profile of spontaneously hypertensive rats (SHRs). The aim of the present study was to determine the influence of GLVs, incorporated (4%) into diets with a 25:1 ω-6/ω-3 FAR, on the erythrocyte fatty acid profile of male SHRs. Methods: SHRs (N = 50) were randomly assigned to one of five dietary groups - standardized control (AIN-76A), Control (25:1 ω-6/ω-3 FAR), CG (25:1 ω-6/ω-3 FAR + 4% CG), PL (25:1 ω-6/ω-3 FAR + 4% PL) or SPG (25:1 ω-6/ω-3 FAR + 4% SPG). Following 6 weeks consumption of diets, SHRs erythrocyte fatty acid profiles were determined by gas-liquid chromatography. Results: Significantly lower percentages of total saturated fatty acids (p < 0.05) and greater percentages of polyunsaturated fatty acids were present among SHR erythrocytes following the consumption of diets containing CG, PL and SPG. Total polyunsaturated fatty acids were greatest among SHRs consuming diets containing purslane. Conclusions: The present study demonstrates the ability of GLVs to mitigate the potential effects of an elevated ω-6/ω-3 FAR, which may contribute to an atherogenic fatty acid profile, inflammation and disease pathogenesis. Dietary recommendations for disease prevention should consider the inclusion of these GLVs, particularly among those consuming diets with an ω-6/ω-3 FAR that may promote disease.
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Matthias B Schulze and colleagues discuss current knowledge on the associations between dietary patterns and cancer, coronary heart disease, stroke, and type 2 diabetes, focusing on areas of uncertainty and future research directions © Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to.
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Linoleic acid (LA) (n-6) and α-linolenic acid (ALA) (n-3) are essential fatty acids (EFAs) as they cannot be synthesized by humans or other higher animals. In the human body, these fatty acids (FAs) give rise to arachidonic acid (ARA, n-6), eicosapentaenoic acid (EPA, n-3), and docosahexaenoic acid (DHA, n-3) that play key roles in regulating body homeostasis. Locally acting bioactive signaling lipids called eicosanoids derived from these FAs also regulate diverse homeostatic processes. In general, ARA gives rise to pro-inflammatory eicosanoids whereas EPA and DHA give rise to anti-inflammatory eicosanoids. Thus, a proportionally higher consumption of n-3 PUFAs can protect us against inflammatory diseases, cancer, cardiovascular diseases, and other chronic diseases. The present review summarizes major sources, intake, and global consumption of n-3 and n-6 PUFAs. Their metabolism to biosynthesize long-chain PUFAs and eicosanoids and their roles in brain metabolism, cardiovascular disease, obesity, cancer, and bone health are also discussed.
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Despite a history of purslane usage as a herbal treatment for dyslipidemia and hyperglycemia management, existing evidence from clinical trials is controversial. The aim for the current study was to evaluate the efficacy of purslane supplementation on lipid parameters and glycemic status in adult populations. A systematic review was conducted in PubMed, Scopus, ISI Web of Science, and Google Scholar up to January 15, 2018, searching for randomized controlled trials that assessed the impact of purslane on fasting blood glucose (FBG), triglycerides, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). Based on the detected heterogeneity between studies, a random- or fixed-effect model was applied in the meta-analysis. The findings from six randomized controlled trials, comprising 352 participants, indicated that purslane can reduce FBG (-4.54 mg/dl, 95% CI [-7.54, -1.53]; I2 = 0.53%) and triglycerides (-19.16 mg/dl, 95% CI [-38.17, -0.15]; I2 = 0%) levels. Changes in TC, LDL-C, and HDL-C concentrations did not reach a statistically significant level. Subgroup analysis showed a favorable effects of purslane on FBG, triglycerides, TC, and LDL-C in a subset of studies in which purslane was administered >1.5 g/day. Categorization based on gender showed that purslane was more effective in improving FBG, TC and LDL-C in females compared with males. This systematic review and meta-analysis suggested that the purslane might be effective on the improvement of blood lipid and glucose levels. Further robust studies with sufficient durations and dosages of supplementation are needed to confirm these results.
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Nitric oxide (NO), generated from L-arginine and oxygen by NO synthases, is a pleiotropic signaling molecule involved in cardiovascular and metabolic regulation. More recently, an alternative pathway for the formation of this free radical has been explored. The inorganic anions nitrate (NO3-) and nitrite (NO2-), originating from dietary and endogenous sources, generate NO bioactivity in a process involving seemingly symbiotic oral bacteria and host enzymes in blood and tissues. The described cardio-metabolic effects of dietary nitrate from experimental and clinical studies include lowering of blood pressure, improved endothelial function, increased exercise performance, and reversal of metabolic syndrome, as well as antidiabetic effects. The mechanisms underlying the salutary metabolic effects of nitrate are being revealed and include interaction with mitochondrial respiration, activation of key metabolic regulatory pathways, and reduction of oxidative stress. Here we review the recent advances in the nitrate-nitrite-NO pathway, focusing on metabolic effects in health and disease.
Article
The aim of this study was to derive dietary patterns associated with cardio-metabolic traits and to examine whether these predict prospective changes in these traits and incidence of the metabolic syndrome (iMetS). Subjects from the Malmö Diet and Cancer Study cardiovascular cohort without cardio-metabolic disease and related drug treatments at baseline ( n 4071; aged 45–67 years, 40 % men) were included. We applied reduced rank regression on thirty-eight foods to derive patterns that explain variation in response variables measured at baseline (waist circumference, TAG, HDL- and LDL-cholesterol, systolic and diastolic blood pressure, fasting glucose and insulin). Patterns were examined in relation to change in cardio-metabolic traits and iMetS in subjects who were re-examined after 16·7 years ( n 2704). Two dietary patterns (‘Western’ and ‘Drinker’) were retained and explained 3·2 % of the variation in response variables. The ‘Western’ dietary pattern was inversely associated with HDL-cholesterol and positively with all other response variables (both at baseline and follow-up), but there was no association with LDL at follow-up. After adjustment for potential confounders, the ‘Western’ dietary pattern was associated with higher risk of iMetS (hazard ratio Q4 v. Q1: 1·47; 95 % CI 1·23, 1·77; Ptrend =1·5×10 ⁻⁵ ). The ‘Drinker’ dietary pattern primarily explained variation in HDL and was not associated with iMetS. In conclusion, this study supports current food-based dietary guidelines suggesting that a ‘Western’ dietary pattern with high intakes of sugar-sweetened beverages and red and processed meats and low intakes of wine, cheese, vegetables and high-fibre foods is associated with detrimental effects on cardio-metabolic health.
Article
Background & aims Cruciferous vegetables contain isothiocyanates, which effectively reduce inflammation and oxidative stress related to chronic diseases, inhibit the bioactivation of procarcinogens, and enhance the excretion of carcinogens. However, at present, no large cohort studies have investigated the effect of cruciferous vegetable on mortality. We aimed to examine the association between cruciferous vegetable intake and all-cause mortality, namely cancer, heart disease, cerebrovascular disease, and injuries, in a large cohort study conducted between 1990 and 1993, in Japan. Methods The analysis included 88,184 participants (age: 45–74 years) with no history of cancer, myocardial infarction, and stroke. Participants were tracked for a median of 16.9 years, during which 15,349 deaths were occurred. The association between cruciferous vegetable intake and risk of all-cause and cause-specific mortality was determined by Cox proportional hazard regression analysis to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs), after adjustment for potential confounding factors. Results An inverse association was found between cruciferous vegetable intake and total mortality in both gender. HRs (95% CI) for all-cause mortality in the highest compared to the lowest quintile were 0.86 (0.80, 0.93) for men (P = 0.0002 for trend) and 0.89 (0.81, 0.98) for women (P = 0.03 for trend). Cruciferous vegetable intake was associated with lower cancer mortality in men, as well as with heart disease-, cerebrovascular disease-, and injury-related mortality in women. Conclusions This prospective study suggests that a higher cruciferous vegetables intake is associated with reduced risk of all-cause mortality. Clinical Trial Registry number and website UMIN000028786, https://upload.umin.ac.jp/cgi-open-bin/ctr/index.cgi.
Article
Cardiovascular disease (CVD) morbidity and mortality is increasing, representing an important public health issue worldwide. It is well-known that risk of CVD is substantially influenced by lifestyle, including poor diet, tobacco smoking and physical inactivity. In the last years, the so-called Mediterranean Diet (MedDiet) has been associated with broad healthy benefits on human health, including protection against CVD. The present narrative review aimed to summarize and discuss the evidence from meta-analyses of epidemiological and clinical trials analyzing MedDiet and CVD risk. The MedDiet is one of the best dietary patterns analyzed in relation to CVD risk and other health outcomes. Studies demonstrated that MedDiet has beneficial effects in the prevention of total and specific types of CVD, albeit a moderate-high degree of inconsistency has been reported and few studies have been included in most of the meta-analyses. As consequence, more high-quality prospective cohorts and randomized clinical trials are warranted in order to increase the confidence in the effect estimates.