Content uploaded by Magda Gamba
Author content
All content in this area was uploaded by Magda Gamba on May 14, 2021
Content may be subject to copyright.
Full Terms & Conditions of access and use can be found at
https://www.tandfonline.com/action/journalInformation?journalCode=bfsn20
Critical Reviews in Food Science and Nutrition
ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/bfsn20
Bioactive compounds and nutritional composition
of Swiss chard (Beta vulgaris L. var. cicla and
flavescens): a systematic review
Magda Gamba , Peter Francis Raguindin , Eralda Asllanaj , Francesco Merlo ,
Marija Glisic , Beatrice Minder , Weston Bussler , Brandon Metzger , Hua
Kern & Taulant Muka
To cite this article: Magda Gamba , Peter Francis Raguindin , Eralda Asllanaj , Francesco Merlo ,
Marija Glisic , Beatrice Minder , Weston Bussler , Brandon Metzger , Hua Kern & Taulant Muka
(2020): Bioactive compounds and nutritional composition of Swiss chard (Beta�vulgaris L. var.
cicla and flavescens): a systematic review, Critical Reviews in Food Science and Nutrition, DOI:
10.1080/10408398.2020.1799326
To link to this article: https://doi.org/10.1080/10408398.2020.1799326
View supplementary material Published online: 04 Aug 2020.
Submit your article to this journal Article views: 28
View related articles View Crossmark data
REVIEW
Bioactive compounds and nutritional composition of Swiss chard (Beta vulgaris
L. var. cicla and flavescens): a systematic review
Magda Gamba
a
, Peter Francis Raguindin
a,b
, Eralda Asllanaj
c
, Francesco Merlo
a
, Marija Glisic
a,b
,
Beatrice Minder
d
, Weston Bussler
e
, Brandon Metzger
e
, Hua Kern
e
, and Taulant Muka
a
a
Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland;
b
Swiss Paraplegic Research, Nottwil, Switzerland;
c
Department of Epidemiology, Erasmus MC, Rotterdam, the Netherlands;
d
Public Health & Primary Care Library, University Library of Bern,
University of Bern, Bern, Switzerland;
e
Nutrition Innovation Center, Standard Process Inc, Palmyra, Wisconsin, USA
ABSTRACT
Swiss chard (Beta vulgaris L. var. cicla or flavescens) is a green leafy vegetable whose bioactive
compounds have been studied due to its effects on health. We systematically reviewed the nutri-
tional profile and bioactive composition of Swiss chard and reported their concentrations. Four
main databases were searched for studies analyzing the chemical composition of Swiss chard.
Screening, selection of articles, and data extraction were carried out by two independent
reviewers. Twenty-eight articles of 1102 records identified by bibliographic search met our inclu-
sion criteria for final analysis. We found a total of 192 chemical compounds categorized into 23
groups. The cicla variety was the most studied, and nutrients and phytochemicals were reported
mainly on leaves. Betalains with 20% of the reported data, fats (16%), flavonoids (11%), non-flavon-
oid phenolics (11%), terpenes and derivatives (8%), carbohydrates (7%), and minerals (6%) were
among the most reported categories. Swiss chard leaves have the highest content of fiber, sodium,
magnesium, flavonoids, and vitamin C, while stems are high in potassium. Swiss chard should be
considered a source of nutrients and phytochemicals, and further research is needed on identifying
and quantifying other bioactive compounds and understanding their impact on health.
KEYWORDS
Beta vulgaris; bioactive
compounds; minerals;
nutritional profile;
phytochemicals; Swiss chard
Introduction
Green leafy vegetables (GLVs) have been recently recom-
mended for consumption in the everyday diet; they are low
in energy but relatively high in micronutrients. Experimental
studies show that increased consumption of green vegetables
can prevent coronary heart disease by inhibiting the develop-
ment of atherosclerosis (Sener et al. 2002; Adams et al. 2006).
Indeed, a meta-analysis of observational studies reported a
15.8% decreased risk of developing cardiovascular disease
associated with high consumptions of GLVs (Pollock 2016).
Other epidemiological studies have shown a potential benefit
of GLVs in diabetes, cognitive decline and overall mortality
(Chen et al. 2018; Morris et al. 2018;Morietal.2019).
Swiss chard (Beta vulgaris cicla, BVc and Beta vulgaris
flavescens, BVf), an edible plant of the Chenopodiaceae fam-
ily, is considered one of the GLVs. The plant has a thick,
crunchy stalk that can be white or colorful and wide fanlike
green leaves (Rana 2016). Leaves can be consumed raw as
part of a salad or cooked alone or along with the stems in a
similar way as spinach (Dietitians of Canada 2020). It is
commonly found in the Western diet and is rich in bioactive
chemicals such as phytopigments, flavonoids and minerals
with antioxidant and immunomodulating properties
(Ivanovic et al. 2019). Swiss chard is also rich in dietary
fibers, proteins and antioxidants such as alpha-lipoic acid,
which is linked to lower glucose levels and increased insulin
sensitivity (Ivanovic et al. 2019; Yang et al. 2014). Therefore,
Swiss chard has potential preventive and therapeutic effects
in diabetes, as seen in animal studies (Sener et al. 2002).
Among GLVs, Swiss chard has considerable levels of nitrate,
involved in the pathophysiology of atherosclerosis (Freeman
et al. 2017). The available evidence suggests a possible health
benefit of GLVs, yet epidemiological studies are lacking on
the association of Swiss chard consumption with cardiome-
tabolic diseases and other health outcomes. Thus, it is
important to understand better the nutrient and phytochem-
ical content of Swiss chard since it may provide more clues
on its health effects. Therefore, a comprehensive quantitative
review is required, also given the global micronutrient defi-
ciency, increased incidence of chronic diseases and Swiss
chard being an easy to grow and inexpensive vegetable crop
available throughout the year (Ivanovic et al. 2019; Ninfali
and Angelino 2013). We conducted a systematic review of
studies evaluating the presence and levels of nutrients and
bioactive components in Swiss chard.
CONTACT Taulant Muka taulant.muka@ispm.unibe.ch Institute of Social and Preventive Medicine, University of Bern, Bern, 3012 Switzerland.
Supplemental data for this article can be accessed at https://doi.org/10.1080/10408398.2020.1799326.
These authors contributed equally to this work.
This article has been republished with minor changes. These changes do not impact the academic content of the article.
ß2020 Taylor & Francis Group, LLC
CRITICAL REVIEWS IN FOOD SCIENCE AND NUTRITION
https://doi.org/10.1080/10408398.2020.1799326
Methods
Literature search
This review was conducted and reported following the
PRISMA 10 (eAppendix 1), as well as based on the system-
atic review approach designed by Muka et al. (2020).
Published studies examining the nutrient and bioactive com-
position of Swiss chard were identified from inception until
January 22, 2020 (date last searched) using four biblio-
graphic databases (PubMed, Embase, Web of Science, and
Cochrane trials). Search terms were related to nutrient and
bioactive compounds (e.g., nutrients, metabolism, phyto-
chemical, carbohydrate, fatty acids) and the plant (Swiss
chard) (eAppendix 2). We did not apply any restrictions
concerning language and publication date. Conference
abstracts, cost-effectiveness studies, letters to the editor, con-
ference proceedings, literature reviews, systematic reviews,
or meta-analyses and, studies conducted in animals were
excluded. To retrieve further relevant publications, we
checked the reference lists of studies included in the cur-
rent review.
Study selection criteria
Studies were included if they met the following criteria: (1)
used samples of any part of Swiss chard or its seeds; and (2)
evaluated nutrient and bioactive compounds. We excluded
studies in which Swiss chard was genetically manipulated
and if the analysis included Swiss chard-based dietary sup-
plements or meals. Two reviewers independently evaluated
the titles and abstracts according to the inclusion criteria.
For each potentially eligible study, two reviewers assessed
the full-text for relevance. In cases of disagreement, a deci-
sion was made by consensus or, if necessary, a third
reviewer was consulted.
Data extraction
Two reviewers using a predesigned form including first
author and publication year, variety, cultivar (cv.), analyzed
part of the plant, compounds name, their concentrations,
and biological activity reported in the articles did data
extraction independently.
Classification and report of compounds
All compounds were classified into categories according to
their chemical structure. This cataloging was established
using the PubChem Database of the U.S. National Library of
Medicine (Kim et al. 2019), which provides several types of
chemical structure classifications. In our case, we used the
“KEGG Phytochemical Compounds”classification, if avail-
able. Otherwise, we categorized the compounds using the
“MeSH tree”classification. The compounds not identified or
not included in the PubChem database were organized
according to the category reported by the authors. In case
the authors did not classify the compounds, we allocated
them in the “other compounds”category. All categories and
compounds are reported in alphabetical order or numerical
order if the name starts with numbers or words
denoting them.
The names of compounds were included as they were
originally reported in papers, and to allow easy identifica-
tion thereof, we tagged them with their respective
“PUBCHEM Single Compound accession identifier”
(CID) when possible. Compounds that were reported by
more than one author with different names or terms were
grouped under the same Pubchem CID. Authors report-
ing the same compound were listed according to the year
of publication (from earliest to latest). Regarding the con-
centrations of the compounds, we reported the original
units described in papers. However, we converted the ori-
ginal units to mg/100 g of fresh weight (F.W.) or mg/
100 g of dry weight (D.W.) when feasible, to make the
reports uniform and comparable across studies.
Results
The systematic search in the electronic databases identified
1102 potentially relevant citations. After screening abstracts
and full-texts papers, cross-referencing and consulting other
sources, we selected 28 articles to include in this review
(Figure 1), from which 20 (71%) reported concentrations on
the compounds they were identifying.
Cicla was the most studied variety, while the flavescens
variety was described only in two papers, one reporting car-
otenoids and the other one flavonoids (Table 1). Twelve
authors did not state the cultivar they used for analysis.
Among those who did report, the most commonly used
were Bright light and Lukullus with three articles, each. We
found the leaf as the most studied part, with 21 authors
describing results on it alone or together with other parts,
mainly stems, stalks, or petioles (Table 1 and Supplemental
Table 1). Stems, stalks, or petioles were the second most fre-
quently reported part of the plant, with five articles report-
ing compounds on them also alone (two articles) or
together with leaves. Followed by three papers that described
seeds, one that studied roots, and one that used whole plant
(tissue). Two articles did not indicate the used part of the
Swiss chard for the analysis (Moyo et al. 2017; Ferland and
Sadowski 1992).
This systematic review found a total of 192 bioactive com-
ponents described in Swiss chard, which were categorized into
23 groups (Supplemental Table 2). Among the total com-
pounds, 20% were classified as betalains being this the largest
category, followed by 16% classified as fats, lipids and fatty
acids, 11% as flavonoids and derivatives, and 8% as terpenes
and derivatives (Figure 2). The concentration of the com-
pounds was available in 114 (59%) of the 192 nutrients and
phytochemicals included in this study (Supplemental Table 2).
Theonlycategorywithnoreportedconcentrationsofthe
compounds was enzymes (Dinc¸ler and Aydemir 2001;Gao,
Hian and Xiao 2009). All the categories were studied in leaves,
and five (betalains, flavonoids, minerals, non-flavonoid phe-
nolics, and vitamins) were also described in stems, stalks, or
petioles. In seeds, studies reported carboxylic acids, flavonoids
2 M. GAMBA ET AL.
and non-flavonoid phenolics, which was similar to the find-
ings in roots except for the category of carboxylic acids. In
the tissue (leaves and stems together) of Swiss chard were
analyzed the Proximate composition, carotenoids, flavonoids,
minerals, pigments, non-flavonoid phenolics, and vitamins
(Supplemental Table 1). The specific results for Swiss chard
Proximate composition and the largest compounds categories
are presented hereunder.
Proximate composition of Swiss chard
Five authors reported compounds related to the Proximate
composition of Beta vulgaris in the cicla variety (Zeller,
Rudolph, and Hoppe 1977; Sacan and Yanardag 2010;
Colonna et al. 2016; Ivanovic et al. 2019; Mzoughi et al.
2019). Carbohydrates, fat and protein were reported in
leaves and the tissue. The concentration values in the tissue
Figure 1. Flowchart of studies reporting nutrients and bioactive composition of Beta vulgaris var. cicla/flavescens.
CRITICAL REVIEWS IN FOOD SCIENCE AND NUTRITION 3
were up to 3.8 fold higher than in leaves, similar to the fat
content (Table 2a). Ash and total fiber concentrations were
studied only in leaves, and these results can be compared
with those reported in the FoodData Central (Swiss chard,
raw) of the U.S. Department of Agriculture (USDA 2019).
For total carbohydrates (3740 mg/100 g vs. 2158 mg/100 g)
and fats (200 mg/100 g vs. 99 mg/100 g, the value reported in
the FoodData central (2019) is higher than reported data by
Mzoughi et al. (2019). Regarding proteins, the amounts are
similar between FoodData Central (1800 mg/100 g) and the
amount reported by Colonna et al. (2016) (1500 mg/100 g).
The only value in our review that is higher compared to
those reported by the USDA is fiber, given that Mzoughi
et al. (2019) found 2430 mg/100 g vs. 1600 mg/100 g reported
by the USDA.
Betalains
Betalains are water-soluble nitrogen-containing pigments
derived from betalamic acid and divided into two groups:
betacyanins (red to red-violet tonalities) and betaxanthins
(yellow-orange tonalities) (Esquivel 2016). Three articles
(Kugler et al. 2007; Kugler, Stintzing, and Carle 2004; Ali,
Khandaker, and Oba 2009) reported on this category in the
Swiss chard variety cicla, with two of them belonging to
Kugler et al. (Kugler, Stintzing, and Carle 2004; Kugler et al.
2007). The articles focused on the petioles or stems of the
cv. Bright Lights since this is the colored part of the plant.
Thirty-five compounds from both groups of betalains were
identified (Supplemental Table 2), but only the total concen-
trations of betacyanins, betaxanthins and betalains were
quantified in four different Swiss chard petiole’s colors of
the cultivar mentioned above (Table 2b). The highest con-
centration of betaxhantins was found in the yellow petioles
(10.74 mg/100 g F.W.), while betacyanins and the total con-
tent of betalains were higher in the purple-colored ones
(5.87 mg/100 g F.W. and 7.54 mg/100 g F.W., respectively).
The higher content of total betaxanthins than total betalains
could be due to different methods of analysis used by
Kugler et al. in his two papers (Kugler et al. 2007; Kugler,
Stintzing, and Carle 2004). Our review did not find any art-
icle reporting concentrations for any individual betalains.
Regarding the biological activity in the three articles
assessing betalains, only one paper analyzing this chemical
group (Ali, Khandaker, and Oba 2009) mentioned and
measured its antioxidant activity. The authors compared the
antioxidant activity of five leafy vegetables, where Swiss
chard ranked third among them.
Fat, lipids, fatty acids, and related compounds
After betalains, this category with 25 compounds described
in three papers (Zeller, Rudolph, and Hoppe 1977; Ivanovic
et al. 2019; Mzoughi et al. 2019) is the second-ranked list of
constituents, and the description was done exclusively in the
cicla variety. Authors identified seventeen fatty acids, five
lipids and three fat-related compounds (Supplemental Table
2) including the total concentration of monounsaturated
fatty acids, polyunsaturated fatty acids, saturated fatty acids,
and the unsaturated/saturated fatty acids ratio
(Supplemental Table 3). The quantitative analysis of this
group of compounds was available for 17 fatty acids and
three fat-related chemicals analyzed by Mzoughi et al.
(2019) in the leaves of an unknown cultivar. The results
indicate that linoleic acid is the most concentrated fatty acid
in Swiss chard leaves, with 26% of the individual fatty acids
in the lipid fraction (Table 2c). Palmitic acid has the
second-highest level with 23%, followed by oleic acid (19%),
stearic acid (8%) and palmitoleic acid (6%) (Figure 3). The
unsaturated/saturated fatty acids ratio reported by Mzoughi
et al. (2019) is 1.40, which is favorable to the prevention of
cardiovascular diseases. Among the three fat-related com-
pounds, (E)-3-octen-1-ol presents the highest concentration
(2.7% of the volatile fraction).
When comparing the concentrations of the fatty acids of
our review with those of the USDA FoodData Central
(2019), the values of the database for linoleic and oleic acid
(63 mg/100 g and 40 mg/100 g, respectively) are twice those
reported by Mzoughi et al. (2019) (26.5 mg/100 g and
19.1 mg/100 g, respectively). The concentration for palmitic
acid is similar between the two information sources (30 mg/
100 g for USDA and 22.9 mg/100 g for Mzoughi et al. 2019).
For both the stearic and palmitoleic acid, the USDA (2019)
reports no concentration (0 mg/100 g), while Mzoughi et al.
(2019) found 8.1 and 6.31 mg/100 g, respectively. These dif-
ferences could be related to the analyzed plant’s variety and
cultivar and the methods applied to quantify the
concentrations.
As for the functional properties of this category, only one
article (Mzoughi et al. 2019) mentioned the importance of
oleic acid, which is present in leaves of Swiss chard, for the
nervous cell construction and its fundamental role in cardio-
vascular disease prevention.
Flavonoids and derivatives
Flavonoids are secondary metabolites corresponding to poly-
phenols, which have varied structures and are distributed in
all the plant’s parts acting as pigments, defense, or growth
regulators (Hern
andez-Rodr
ıguez, Baquero, and Larrota
2019). Flavonoids are composed of a benzo-g-pyrone struc-
ture and three phenolic rings that can present various sub-
stitutions (e.g., the type, number, distribution and
orientations in space) leading to derivatives with distinct
structures and properties (flavonols, flavones, anthocyani-
dins, catechins, flavanones, and isoflavones) (Li et al. 2019).
Regarding this group of bioactive compounds, 20 phyto-
chemicals and the total flavonoid (TFC) and flavonols con-
centrations were found in eleven articles (Gil, Ferreres, and
Tom
as-Barber
an 1998; Kim et al. 2004; Pyo et al. 2004;
Ninfali et al. 2007; Sacan and Yanardag 2010; Gennari et al.
2011; Ninfali and Angelino 2013; Moyo et al. 2017; Ivanovic
et al. 2019; Mohammed et al. 2019; Mzoughi et al. 2019)
that studied all the Swiss chard parts in the cicla variety
(Supplemental Table 2). The most-reported flavonoid was
200-xylosylvitexin, which was identified by three authors (Gil,
4 M. GAMBA ET AL.
Table 1. General characteristics of the papers included in this review.
Author Variety Cultivar Leaves Stems Stalks Petioles Seeds Tissue Roots NR
No. of
included
compounds
Chemical structure
category reported
No. of included
compounds
reported
quantitatively
Zeller, Rudolph, and
Hoppe (1977)
Cicla Glatter Silber x 5 Fat, lipids, fatty acids and
related compounds
0
Ferland and
Sadowski (1992)
NR Not reported x 1 Vitamins 1
Gil, Ferreres, and Tom
as-
Barber
an (1998)
Cicla Green x 7 Flavonoids and derivatives 7
Yellow Vitamins
Dinc¸ler and Aydemir (2001) Cicla Not reported x 1 Enzymes 0
Pokluda and Kuben (2002) Cicla Bright Lights x x 5 Minerals/Trace elements/Metals 5
Cerven
y Vitamins
Fordhook Giant
Gator
Genfer Selma
Charlotte
Listov
y zelen
y
Lucullus - Semo
Lucullus - Semena
Rhubarb
Rhubarb Chard
Swiss Chard
Z€
urcher Gelber
Kim et al. (2003) Cicla Not reported x 4 Carboxylic Acids 0
Non-flavonoids phenols/phenolics
Moreira, Roura, and del
Valle (2003)
Cicla Bresanne x 2 Pigments 2
Vitamins
Kim et al. (2004) Cicla Not reported x 4 Flavonoids and derivatives 0
Terpenes and derivatives
Kugler, Stintzing, and
Carle (2004)
Cicla Bright Lights x 31 Betalains 3
Pyo et al. (2004) Cicla Large w. ribbed x x 16 Flavonoids and derivatives 2
CXS 2550 Non-flavonoids phenols/phenolics
Kugler et al. (2007) Cicla Bright Lights x 26 Betalains 1
Ninfali et al. (2007) Cicla Not reported x 5 Flavonoids and derivatives 1
Non-flavonoids phenols/phenolics
Dzida and Pitura (2008) Cicla Lukullus x 5 Minerals/Trace elements/Metals 5
Vitamins
Ali, Khandaker, and
Oba (2009)
Cicla Not reported x 3 Betalains 0
Non-flavonoids phenols/phenolics
Pigments
Gao, Han, and Xiao (2009) Cicla Red x 1 Enzymes 0
Kolota, Sowinska, and
Czerniak (2010)
Cicla Lukullus x x 5 Minerals/Trace elements/Metals 5
Green White Ribbed Vitamins
Vulcan
Bresanne
Green Silver
Sacan and Yanardag (2010) Cicla Not reported x 4 Anthocyanins 4
Flavonoids and derivatives
Non-flavonoids phenols/phenolics
Proteins and aminoacides
Bozokalfa et al. (2011) Cicla Not reported x 9 Minerals/Trace elements/Metals 9
Gennari et al. (2011) Cicla Not reported x 7 Flavonoids and derivatives 1
(continued)
CRITICAL REVIEWS IN FOOD SCIENCE AND NUTRITION 5
Table 1. Continued.
Author Variety Cultivar Leaves Stems Stalks Petioles Seeds Tissue Roots NR
No. of
included
compounds
Chemical structure
category reported
No. of included
compounds
reported
quantitatively
Non-flavonoids phenols/phenolics
Ninfali and Angelino (2013) Cicla Not reported x x x 2 Flavonoids and derivatives 2
Non-flavonoids phenols/phenolics
Reif et al. (2013) Fla-vescens Berac x 2 Carotenoids 2
Charlotte
Miceli and Miceli (2014) Cicla Verde da taglio x 2 Pigments 2
Vitamins
Colonna et al. (2016) Cicla Agila x 7 Minerals/Trace elements/Metals 7
Non-flavonoids phenols/phenolics
Proteins and aminoacides
Vitamins
Moyo et al. (2017) Cicla Fordhook Giant x 20 Carotenoids 2
Flavonoids and derivatives
Minerals/Trace elements/Metals
Non-flavonoids phenols/phenolics
Ivanovic et al. (2019) Cicla Verca F1 hybrid x 22 Ash 22
Carbohydrates, soluble sugars
and polyols
Carotenoids
Fat, lipids, fatty acids and
related compounds
Fibers
Flavonoids and derivatives
Pigments
Proteins and aminoacides
Minerals/Trace elements/Metals
Non-flavonoids phenols/phenolics
Mohammed et al. (2019) Fla-vescens Not reported x 5 Flavonoids and derivatives 0
Mzoughi et al. (2019) Cicla Not reported x 98 Alcohols 98
Aldehydes
Alkanes
Ash
Carbohydrates, soluble sugars
and polyols
Carboxylic Acids
Carotenoids
Fat, lipids, fatty acids and
related compounds
Fibers
Flavonoids and derivatives
Heterocyclics
Ketones
Minerals/Trace elements/Metals
Non-flavonoids phenols/phenolics
Pigments
Proteins and aminoacides
Tannins
Terpenes and derivatives
Other compounds
Singh, Dunn, and
Payton (2019)
Cicla Magenta sunset x 2 Minerals/Trace elements/Metals 2
NR, not reported.
6 M. GAMBA ET AL.
Ferreres, and Tom
as-Barber
an 1998; Gennari et al. 2011;
Ninfali et al. 2007) and is a derivative from apigenin.
Apigenin is a compound associated with several biological
functions like antioxidant, anti-inflammatory, antimicrobial
(antibacterial, antifungal, and antiparasitic) and cancer che-
mopreventive (anti-mutagenic, anti-proliferative, and inhibi-
tor of the cell cycle progression) (Wang et al. 2019; Patel,
Shukla, and Gupta 2007). It has beneficial effects on dia-
betes, and neuropsychiatric diseases, among others (Salehi
et al. 2019). Only five compounds were analyzed quantita-
tively by Gil et al. (1998) in leaves of green and yellow cv.
of Swiss chard. Table 2d shows 200-xylosylvitexin as the most
concentrated flavonoid with 193 mg/100 g F.W. in Green cv.,
while in the Yellow another derivative of apigenin, 600 -
Malonyl-200-xylosyl vitexin has the highest concentration
with 144 mg/100 g F.W. Concerning the TFC of Swiss chard,
seven papers reported concentrations in different units and
plant’s part (Sacan and Yanardag 2010; Ninfali and
Angelino 2013; Moyo et al. 2017; Ivanovic et al. 2019;
Mzoughi et al. 2019; Gil, Ferreres, and Tom
as-Barber
an
1998; Pyo et al. 2004) (Supplemental Table 3). Two authors
described TFC in mg/100 g F.W. (Gil, Ferreres, and Tom
as-
Barber
an 1998; Pyo et al. 2004); however, the results show
big disparities because Gil et al. (1998) found a maximal
concentration of 276 mg/100 g F.W. in leaves of green cv.,
while Pyo et al. (2004) reported 28.2 mg/100 g F.W. as the
highest concentration in the tissue of the cv. CXS 2550
(red). These discrepancies could be due to several factors
like the cultivars, the form in which the plant’s part was pre-
pared for extraction, the type of extract studied, and the
methods used to quantify the TFC. The TFC was also
reported in catechin equivalents (CEs) in four studies (Sacan
and Yanardag 2010; Moyo et al. 2017; Ivanovic et al. 2019;
Mzoughi et al. 2019). In this case, we are comparing only
those papers which described their results in the same units
of concentration. When the values were informed as mg
(CE)/mg extract, the highest concentration was found on
the tissue of the cv. Verca F1 hybrid (12.05), which is
slightly higher than the value obtained for the leaves of an
unknown Swiss chard cultivar (11.88). Finally, Ninfali and
Angelino (2013) was the only author studying TFC in leaves,
roots and seeds of an unknown cultivar and reported results
in mg/g D.W. The highest amount of total flavonoids was
recorded in leaves reaching 7.92 mg/g D.W., which is five
and nine times higher than in seeds and roots, respectively.
The above described biological functions associated with
apigenin were also mentioned as properties of the flavonoids
in six of the eleven reports analyzing this phytochemical
group (Gil, Ferreres, and Tom
as-Barber
an 1998; Kim et al.
2004; Ninfali and Angelino 2013; Moyo et al. 2017; Ivanovic
et al. 2019; Mohammed et al. 2019). The most studied prop-
erty was the antioxidant with four articles reporting it
(Sacan and Yanardag 2010; Gennari et al. 2011; Moyo et al.
2017; Ivanovic et al. 2019). Other reported analyses of the
Swiss chard flavonoids were related to their antidiabetic
(Mohammed et al. 2019; Mzoughi et al. 2019), anticancer
(Ninfali et al. 2007; Gennari et al. 2011), antibacterial
(Mohammed et al. 2019) and hepatoprotective (Kim et al.
2004) properties.
Non-flavonoids phenols/phenolics
Phenolic compounds are a large group of chemical substan-
ces that possess an aromatic ring and a benzene ring with
one or more hydroxide groups, including functional deriva-
tives (esters, methyl esters, glycosides, among others). This
group of bioactives plays a role as secondary metabolites of
plants with various activities like plant growth, reproduction
and defense. The most common form of phenolics in nature
is glycosides, but they can also be found joined to carboxylic
Figure 2. Percentage of total reported compounds by categories of chemicals and bioactive compounds found in Beta vulgaris var. cicla/flavescens.
CRITICAL REVIEWS IN FOOD SCIENCE AND NUTRITION 7
acids, organic acids, amines, lipids, and other phenolic com-
pounds (Barba, Esteve, and Fr
ıgola 2014).
Eleven papers (Kim et al. 2003; Pyo et al. 2004;Ninfali
et al. 2007;Ali,Khandaker,andOba2009; Sacan and
Yanardag 2010; Gennari et al. 2011; Ninfali and Angelino
2013; Colonna et al. 2016; Moyo et al. 2017; Ivanovic
et al. 2019;Mzoughietal.2019) described 18 compounds
identified in the cicla variety(SupplementalTable2).
Only three phytochemicals (myricitrin acid, p-coumaric
acid and rosmarinic acid) were analyzed quantitatively by
Mzoughi et al. (2019) in leaves of a non-reported cultivar
(Supplemental Table 3). p-Coumaric acid is the most
reported compound of this category, with three articles
mentioning it (Mzoughi et al. 2019; Pyo et al. 2004; Moyo
et al. 2017). The total phenolic content (TPC) was studied
in all the parts of the Swiss chard and was measured
in F.W. as mg/100 g and D.W. as mg GAE/100 g (gallic
acid equivalents). The highest reported concentrations
were in the seeds of an unknown cultivar with 24,677 mg
GAE/100 g D.W (Gennari et al. 2011) and 157.8 mg/100 g
in the tissue of cv. CXS 2550 (red) (Pyo et al. 2004)
(Table 2e).
Table 2. Proximate composition of Beta vulgaris (Swiss chard) and most concentrated compounds in the largest chemical categories according to the reported
unit of concentration.
Table 2a. Proximate composition (mg/100 g F.W.)
No. Compound name PubChem CID Variety Cultivar
Mean concentration according to plant’s part
ReferenceTissue Leaves
11 Ash NAp Cicla Verca F1 hybrid 1810 NA Ivanovic et al. (2019)
28 Total carbohydrates NAp Cicla Verca F1 hybrid 6250 NA Ivanovic et al. (2019)
NR NA 2158 Mzoughi et al. (2019)
61 Fat NAp Cicla Verca F1 hybrid 380 NA Ivanovic et al. (2019)
NR NA 99 Mzoughi et al. (2019)
64 Total dietary fiber NAp Cicla NR NA 2430 Mzoughi et al. (2019)
95 Protein NAp Cicla Verca F1 hybrid 2350 NA Ivanovic et al. (2019)
Agila NA 1500 Colonna et al. (2016)
Table 2c. Most concentrated fatty acids in Swiss chard leaves (% of individual fatty acids in the lipid fraction).
No. Compound name PubChem CID Variety Cultivar Concentration (mean) Reference
44 Linoleic acid 5280450 Cicla NR 26.54 Mzoughi et al. (2019)
39 Palmitic acid 985 Cicla NR 22.92 Mzoughi et al. (2019)
43 Oleic acid 445639 Cicla NR 19.15 Mzoughi et al. (2019)
42 Stearic acid 5281 Cicla NR 8.17 Mzoughi et al. (2019)
40 Palmitoleic acid 445638 Cicla NR 6.31 Mzoughi et al. (2019)
Table 2b. Betalains content in Swiss chard petioles (mg/100g F.W.).
No. Compound name PubChem CID Variety Cultivar
Mean concentration according to cultivar color
ReferencePurple Red purple Yellow Yellow–orange
12 Total betaxanthins NAp Cicla Bright lights NA NA 10.74 NA Kugler et al. (2007)
2.43 2.49 4.97 2.2 Kugler et al. (2007)
13 Total betacyanins NAp Cicla Bright lights 5.87 3.03 trace 1.37 Kugler et al. (2007)
14 Total betalains NAp Cicla Bright lights 7.54 5.06 4.97 3.36 Kugler et al. (2007)
Table 2d. Reported concentrations of flavonoids and derivatives in Swiss chard leaves (mg/100g F.W.).
No. Compound name PubChem CID Variety
Mean concentration according to cultivar
ReferenceGreen Yellow
65 200-xylosylvitexin 101406315 Cicla 193 75 Gil, Ferreres, and Tom
as-Barber
an (1998)
66 600-Malonyl-200 -xylosyl vitexin 44257736 Cicla 34 144 Gil, Ferreres, and Tom
as-Barber
an (1998)
67 Isorhamnetin 3-gentiobioside 5488387 Cicla 39 ND Gil, Ferreres, and Tom
as-Barber
an (1998)
68 Isorhamnetin 3-vicianoside 44258010 Cicla 10 ND Gil, Ferreres, and Tom
as-Barber
an (1998)
69 Kaempferol 3-gentiobioside 9960512 Cicla Trace Not quantified Gil, Ferreres, and Tom
as-Barber
an (1998)
Table 2e. Total phenols/phenolics concentration.
No. Compound name PubChem CID Variety Cultivar
Mean concentration
ReferencePlant’s part Value
mg GAE/100 g D.W.
90 Total Phenols NAp Cicla NR Seeds 24677 Gennari et al. (2011)
90 Total Phenols NAp Cicla Agila Leaves 9658 Mzoughi et al. (2019)
90 Total phenolics NAp Cicla Fordhook Giant NR 1104 Moyo et al. (2017)
mg/100 g F.W.
90 Total concentration of phenolics NAp Cicla CXS 2550 (red) Tissue 157.8 Pyo et al. (2004)
90 Total concentration of phenolics NAp Cicla CXS 2550 (red) Leaves 128.1 Pyo et al. (2004)
90 Total concentration of phenolics NAp Cicla Large white ribbed Tissue 124.7 Pyo et al. (2004)
8 M. GAMBA ET AL.
Seven papers (Pyo et al. 2004; Ali, Khandaker, and Oba
2009; Sacan and Yanardag 2010; Ninfali and Angelino 2013;
Colonna et al. 2016; Moyo et al. 2017; Mzoughi et al. 2019)
attributed to phenols a central role in the antioxidant prop-
erty seen in Swiss chard. One article has also assessed and
reported that these phytochemicals present anti-inflamma-
tory and anticancer properties (Kim et al. 2003).
Terpenes and derivatives
Terpenes are the largest class of compounds found in essential
oils and are made up of isoprene molecules that, according to
their structure, can be subdivided into acyclics (linear) or
cyclics (ring) (Bas¸er and Demirci 2007). Several terpenes and
derivatives are biologically active, and their effects have been
studied against cancer, inflammation, and a variety of infectious
diseases (Mbaveng, Hamm, and Kuete 2014). Among this cat-
egory, sixteen compounds were identified (Supplemental Table
2) by two authors (Kim et al. 2004;Mzoughietal.2019)who
analyzed only the leaves of the cicla variety. Mzoughi et al.
(2019) quantified the concentrations of fourteen terpenes and
derivatives as percentages of the total volatiles. As can be seen
in Table 2f and Figure 3,a-terpineol and b-Pinene are both
the most concentrated phytochemicals in this category, with
5.8% each of them. None of the papers analyzing this group
mentioned any functional properties or conducted assays where
terpenes from Swiss chard would play a role.
Carbohydrates, soluble sugars and total polyols
Soluble sugars, which are defined as mono- and disacchar-
ides, play a major role in plant’s physiological processes as
photosynthesis, transport and heterotrophic energy utiliza-
tion, and in the metabolic pathways related to the produc-
tion of reactive oxygen species (Cou
ee et al. 2006). Mzoughi
et al (2019) is the only author describing sugars and polyols
in leaves of an unknown cultivar of the cicla variety
(Supplemental Table 2). The total carbohydrate content was
already mentioned in the proximate composition section.
Regarding sugars, a total of nine compounds were reported
(Supplemental Table 3). Sucrose is the most concentrated
sugar (1115 mg/100 g F.W.) exceeding by far the amounts of
glucose (285 mg/100 g F.W.) and inositol (285 mg/100 g
F.W.) (Figure 3).
Table 2f. Most concentrated terpenes and derivatives in Swiss chard leaves (% of total volatiles).
No. Compound name PubChem CID Variety Cultivar Concentration (mean) Reference
98 a-terpineol 17100 Cicla NR 5.8 Mzoughi et al. (2019)
102 b-Pinene 14896 Cicla NR 5.8 Mzoughi et al. (2019)
108 Limonene 22311 Cicla NR 5.6 Mzoughi et al. (2019)
107 Geraniol 637566 Cicla NR 3 Mzoughi et al. (2019)
104 Citronellol 8842 Cicla NR 2.8 Mzoughi et al. (2019)
Table 2g. Most concentrated minerals.
No.
Compound
name PubChem CID Variety Cultivar
Mean concentration according to plant’s part
ReferenceLeaves Stalks/petioles Tissue
mg/100 g F.W.
81 K 5462222 Cicla Listov
y zelen
y 705.1 759.4 NA Pokluda and Kuben (2002)
Verca F1 hybrid NA NA 366.2 Ivanovic et al. (2019)
84 Na 5360545 Cicla Listov
y zelen
y337.9 140.1 NA Pokluda and Kuben (2002)
Z€
urcher Gelber 236.6 179 NA Pokluda and Kuben (2002)
Verca F1 hybrid NA NA 130.2 Ivanovic et al. (2019)
82 Mg 5462224 Cicla NR 307.1 NA NA Mzoughi et al. (2019)
Listov
y zelen
y 60.9 14.3 NA Pokluda and Kuben (2002)
Verca F1 hybrid NA NA 91.8 Ivanovic et al. (2019)
76 Ca 5460341 Cicla NR 154.1 NA NA Mzoughi et al. (2019)
Cerven
y 63.6 43.8 NA Pokluda and Kuben (2002)
Verca F1 hybrid NA NA 168.9 Ivanovic et al. (2019)
85 P 5462309 Cicla Agila 19.1 NA NA Colonna et al. (2016)
Verca F1 hybrid NA NA 60.5 Ivanovic et al. (2019)
mg/100 g D.W.
81 K 5462222 Cicla NR 3685 NA NA Bozokalfa et al. (2011)
82 Mg 5462224 Cicla NR 542 NA NA Bozokalfa et al. (2011)
84 Na 5360545 Cicla NR 396 NA NA Bozokalfa et al. (2011)
85 P 5462309 Cicla NR 355 NA NA Bozokalfa et al. (2011)
76 Ca 5460341 Cicla NR 351 NA NA Bozokalfa et al. (2011)
Percentage (%) D.W.
81 K 5462222 Cicla Lukullus 9.23 NA NA Dzida and Pitura (2008)
Ribbed 6.24 8.43 NA Kolota, Sowinska, and Czerniak (2010)
76 Ca 5460341 Cicla Lukullus 1.3 NA NA Dzida and Pitura (2008)
Green White 0.1 0.18 NA Kolota, Sowinska, and Czerniak (2010)
85 P 5462309 Cicla Lukullus 1.19 NA NA Dzida and Pitura (2008)
Green White 0.45 0.43 NA Kolota, Sowinska, and Czerniak (2010)
82 Mg 5462224 Cicla Lukullus 0.94 NA NA Dzida and Pitura (2008)
Bresanne 0.67 0.43 NA Kolota, Sowinska, and Czerniak (2010)
NAp, not applicable; NA, not analyzed; NR, not reported; ND, not determined or traces.
CRITICAL REVIEWS IN FOOD SCIENCE AND NUTRITION 9
Other compounds categories
Due to the nutritional and health importance of other com-
pounds categories that were not among the largest ones, we
describe here the results for carotenoids, minerals and trace
elements, and vitamins that include 16 compounds.
For the carotenoids category, we found four papers (Reif
et al. 2013; Moyo et al. 2017; Ivanovic et al. 2019; Mzoughi
et al. 2019) analyzing b-carotene, lutein and lycopene, in
leaves of three different types of cultivars belonging to the
cicla and flavescens varieties (Supplemental Table 2). The
highest reported value in this category corresponds to lutein
(5.13 mg/100 g F.W.) detected in the cv. Charlotte of the fla-
vescens variety (Supplemental Table 3). The b-carotene con-
tent was highest in the cv. Charlotte of the flavescens variety
(4.48 mg/100 g F.W.) as reported by Reif et al. (2013); how-
ever, this concentration is five times higher than the one
found by Mzoughi et al. (0.05 mg/100 g F.W.) (2019). This
difference could be due to the plant varieties or the type of
solvents used to extract the chemicals (Methanol - acetate
solvent for flavescens variety and acetone solvent for the
cicla variety). We compared the values for the cv. Charlotte
with those referenced by the USDA (3.64 mg/100 g F.W.)
(USDA 2019), and found a minimal difference. It is import-
ant to mention that 100 g of Swiss chard leaves (cv.
Charlotte) contribute 47% (373 mg/100 g F.W.) of the mean
recommended dietary allowance (RDA) for vitamin A in
adults (800 mg Retinol Activity Equivalents) (Institute of
Medicine (US) Panel on Micronutrients 2001) making this
cultivar a significant dietary source of vitamin A.
Concerning the minerals, trace elements and metals
category, the concentrations of eleven elements were
determined in the leaves, petioles or stalks, and the whole
tissue in 21 cultivars of the cicla varietybynineauthors
(Pokluda and Kuben 2002;DzidaandPitura2008;
Kolota, Sowinska, and Czerniak 2010; Bozokalfa et al.
2011; Colonna et al. 2016; Moyo et al. 2017; Ivanovic
et al. 2019;Mzoughietal.2019;Singh,Dunn,andPayton
2019) (Supplemental Table 2). Potassium was the most
reported mineral being described for all the authors
included in this category and followed by calcium and
magnesium with eight papers analyzing each of them. We
found that the concentrations were expressed in different
units, as showed in Table 2g. For those minerals reported
in mg/100 g of F.W., the highest amount corresponds to
potassium in the stalks of the cv. Listov
yzelen
y
(759.4 mg/100 g), although the difference comparing with
the content in leaves of the same cultivar is not large
(705.1 mg/100 g). Sodium is ranked as the second most
concentrated mineral, followed by magnesium, calcium,
and phosphorous; all of them have higher levels in leaves
than in stalks (Figure 3). When comparing parts of the
plant with the tissue (leaves and stems together), concen-
trations are higher in the latter for calcium and phos-
phorus. Nevertheless, it is important to highlight that the
studies reporting for every part of the plant (Pokluda and
Kuben 2002;Mzoughietal.2019) or the tissue (Ivanovic
et al. 2019) are different, which implies dissimilarities in
the utilized cultivar, cultivation methods and chemical
assays on the plants. When reviewing the data described
in mg/100 g D.W. by Bozokalfa et al. (2011), who ana-
lyzed only leaves of an unknown cultivar, potassium
ranks first once more with 3685 mg followed in this case
Figure 3. Five main concentrated phytochemicals (mg/100 g) in the largest bioactive compounds’categories for Beta vulgaris var. cicla.
10 M. GAMBA ET AL.
by magnesium with 542 mg; it is also worth noting that
the concentration of sodium in D.W. is quite close to the
one reported in F.W for the same element and in the
same plant’s part. Lastly, this category was also reported
in % of D.W. and analyzed in leaves and stalks. Again,
potassium is first among all the other studied elements
and likewise indicating that this one is the most concen-
trated mineral in Swiss chard. Similar to the results
reported in mg/100 g F.W., the higher concentrations in
% of D.W. occur in leaves. We calculated mean values of
the five most concentrated minerals reported per 100 g
F.W. in leaves to compare them with those of the USDA
(2019). Except for magnesium (mean 52.7 mg/100 g vs.
81 mg/100 g USDA) and phosphorous (mean 19.1 mg/
100 g vs. 46 mg/100 g USDA), all the values were
quite similar.
In the vitamins category, reports were done for vitamin
C and vitamin K or (Phylloquinone) (Vitamin A was ana-
lyzed as b-carotenoid; hence it is part of the “carotenoids”
category). These vitamins were analyzed in eight papers
(Gil, Ferreres, and Tom
as-Barber
an 1998; Pokluda and
Kuben 2002; Moreira, Roura, and del Valle 2003; Dzida and
Pitura 2008; Kolota, Sowinska, and Czerniak 2010; Miceli
and Miceli 2014; Colonna et al. 2016; Ferland and Sadowski
1992) that studied leaves, stalks, and petioles of twenty culti-
vars in the cicla variety for vitamin C. For vitamin K the
analyzed cultivar and part are not stated in the article
(Supplemental Table 2). Regarding vitamin C, the mean
value in leaves is the highest one with 40 mg/100 mg F.W.,
which is almost two-fold the value found by Ivanovic et al.
(2019) in tissue (25.2 mg/100 g F.W.) and almost six-fold the
amount registered in stalks (mean 7.22 mg/100 g F.W.)
(Supplemental Table 3). Comparing the mean value for
leaves with the one from the USDA (30 mg/100 g F.W.)
(USDA 2019), the difference is not remarkable. On vitamin
K, we found only one author (Ferland and Sadowski 1992).
The described content in an unknown part of the plant is
0.917 mg/100 g of F.W., which is 11% higher than the shown
by the USDA (0.83 mg/100 g) (USDA 2019). When compar-
ing the content of vitamin K that we found to the mean
Adequate Intake (AI) for adults (Institute of Medicine (US)
Panel on Micronutrients 2001), one leaf of this plant,
equivalent to 48 g, provides four times the current AI value,
making the Swiss chard a valuable source of Vitamin K.
Highest concentrated bioactive compounds in Beta
vulgaris var. cicla
We have summarized the bioactive compounds with the
twenty highest concentrations reported in mg/100 g F.W. in
Table 3. In cases where a comparison among different parts
of the plant or the whole tissue was possible for a com-
pound, we included only the highest value reported between
all authors for every plant’s part. Macronutrients, fiber, and
some minerals (potassium, sodium and magnesium) are in
the ten most concentrated compounds. As expected, the
highest quantities of carbohydrates, proteins and fat are
found in the whole tissue of Swiss chard; however, a
comparison between the plant’s part is not possible since we
did not find any articles analyzing macronutrients in stalks,
stems or petioles. Minerals seem to be distributed among all
the parts of the Swiss chard with sodium and magnesium
being more present in leaves, calcium and phosphorous in
the whole tissue and potassium in stalks. The total content
of categories like flavonoids and phenolics are also among
the twenty most concentrated compounds, yet a comparison
for the TFC among the plant’s part would not be adequate
since the two authors describing the highest values for this
item (Pyo et al. 2004; Gil, Ferreres, and Tom
as-Barber
an
1998) present dissimilar results. Regarding the TPC, the
highest values quantified by the same author (Pyo et al.
2004) indicate that stalks are the richest part of the plant
containing this type of phytochemicals. Some other com-
pounds appearing in the top twenty most concentrated are
soluble sugars (sucrose, glucose, inositol, and raffinose), fla-
vonoids (200-xylosylvitexin and 600 -Malonyl-200 -xylosyl
vitexin), total chlorophyll and ascorbic acid. None of the
bioactive chemicals reported in the flavescens variety reached
the twenty most concentrated compounds.
Discussion
We identified 192 compounds across 28 articles included in
this systematic review, which describes the nutritional and
phytochemical composition of Beta vulgaris, var. cicla or
flavescens. The most common chemicals reported in the
literature are betalains, fatty acids, flavonoids, minerals,
non-flavonoid phenols, and terpenes.
However, most of our findings are based mainly on
leaves of the cicla variety, since only two papers (Reif et al.
2013; Mohammed et al. 2019) studied the flavescens variety.
We also identified a lack of research using other parts of the
plants like stems/stalks/petioles and seeds for compounds
other than minerals, phenolics and flavonoids. Likewise, our
systematic search could not identify any article regarding
the nutritional and phytochemical composition of Swiss
chard sprouts, which are available for human consumption
in markets as microgreens. Regarding certain compounds
groups like flavonoids, further research is needed to better
understand its contribution to diet as part of Swiss chard
given that we only found one study (Gil, Ferreres, and
Tom
as-Barber
an 1998) identifying individual flavonoids, and
it was published more than twenty years ago. Anthocyanins
are an important group of phytochemicals since they possess
strong biological functions such as anti-inflammatory, anti-
tumor, antimutagenic and antioxidant activities (Kong et al.
2003); still, certain plants (order Caryophyllales) do not pro-
duce anthocyanin but betalains (Tanaka, Sasaki, and
Ohmiya 2008). The motive for this condition is unknown,
and according to some experts, no plant has yet been found
that produces both betalain and anthocyanin pigments
(Stafford 1994; Strack, Vogt, and Schliemann 2003). This
could be the reason why we only found one article (16)
reporting total anthocyanin content in Swiss chard leaves.
Furthermore, none of the papers identifying betalains quan-
tified them individually. Besides vitamin C, K, and vitamin
CRITICAL REVIEWS IN FOOD SCIENCE AND NUTRITION 11
Table 3. Twenty most concentrated compounds reported in mg/100g F.W in Beta vulgaris var. cicla/flavescens (Swiss chard).
Rank No. Category Compound name PubChem CID Variety Cultivar
Concentration mg/100 g F.W. (mean)
ReferenceLeaves Stalks/stems Tissue
1 28 Carbohydrates, soluble sugars and
total polyols
Total carbohydrates NAp Cicla Verca F1 hybrid NA NA 6250
a
Ivanovic et al. (2019)
NR 2158 NA NA Mzoughi et al. (2019)
2 65 Fiber Total dietary fiber NAp Cicla NR 2430
b
NA NA Mzoughi et al. (2019)
Verca F1 hybrid NA NA 770 Ivanovic et al. (2019)
3 96 Proteins and aminoacides Protein NAp Cicla Verca F1 hybrid NA NA 2350
a
Ivanovic et al. (2019)
Agila 1500 NA NA Colonna et al. (2016)
4 23 Carbohydrates, soluble sugars and
total polyols
Sucrose 5988 Cicla NR 1115 NA NA Mzoughi et al. (2019)
5 82 Minerals/trace elements/metals K 5462222 Cicla Listov
y zelen
y 705.1 759.4
c
NA Mzoughi et al. (2019)
Verca F1 hybrid NA NA 366.2 Ivanovic et al. (2019)
6 61 Fat, lipids, fatty acids and
related compounds
Total lipids NAp Cicla Verca F1 hybrid NA NA 380
a
Ivanovic et al. (2019)
Fat NAp Cicla NR 99 NA NA Mzoughi et al. (2019)
7 84 Minerals/trace elements/metals Na 5360545 Cicla Listov
y zelen
y 337.9
b
140.1 NA Pokluda and
Kuben (2002)
Z€
urcher Gelber 236.6 179 NA Pokluda and
Kuben (2002)
Verca F1 hybrid NA NA 130.2 Ivanovic et al. (2019)
8 93 Pigments Chlorophyll contents 6449992 Cicla Bressanne 321.3 NA NA Moreira et al. (2003)
9 82 Minerals/Trace elements/Metals Mg 5462224 Cicla NR 307.1
b
NA NA Mzoughi et al. (2019)
Listov
y zelen
y 60.9 14.3 NA Pokluda and
Kuben (2002)
Verca F1 hybrid NA NA 91.8 Ivanovic et al. (2019)
10 18 Carbohydrates, soluble sugars and
total polyols
Glucose 5793 Cicla NR 285 NA NA Mzoughi et al. (2019)
11 70 Flavonoids and derivatives Total flavonoid content NAp Cicla Green 276
b
NA NA Gil, Ferreres, and Tom
as-
Barber
an (1998)
CXS 2550 (red) 25.2 2.6 28.2 Pyo et al. (2004)
12 65 Flavonoids and derivatives 200 -xylosylvitexin 101406315 Cicla Green 193 NA NA Gil, Ferreres, and Tom
as-
Barber
an (1998)
13 19 Carbohydrates, soluble sugars and
total polyols
Inositol 892 Cicla NR 182 NA NA Mzoughi et al. (2019)
14 76 Minerals/trace elements/metals Ca 5460341 Cicla Verca F1 hybrid NA NA 168.9
a
Ivanovic et al. (2019)
NR 154.1 NA NA Mzoughi et al. (2019)
Cerven
y 63.6 43.8 NA Pokluda and
Kuben (2002)
15 90 Non-flavonoids phenols/phenolics Total concentration of phenolics NAp Cicla CXS 2550 (red) 128.1 157.8
c
29.7 Pyo et al. (2004)
16 66 Flavonoids and derivatives 600 -Malonyl-200 -xylosyl vitexin 44257736 Cicla Yellow 144 NA NA Gil, Ferreres, and Tom
as-
Barber
an (1998)
17 20 Carbohydrates, soluble sugars and
total polyols
Mannitol 6251 Cicla NR 82 NA NA Mzoughi et al. (2019)
18 111 Vitamins Ascorbic acid 54670067 Cicla Verde da taglio 70.6
b
NA NA Mzoughi et al. (2019)
Verca F1 hybrid NA NA 25.2 Ivanovic et al. (2019)
Bright Lights NA 9.9 NA Pokluda and
Kuben (2002)
18 21 Carbohydrates, soluble sugars and
total polyols
Raffinose 439242 Cicla NR 61 NA NA Mzoughi et al. (2019)
20 85 Minerals/trace elements/metals P 5462309 Cicla Verca F1 hybrid NA NA 60.5
a
Ivanovic et al. (2019)
Agila 19.1 NA NA Colonna et al. (2016)
NI, not included in PUBCHEM; NR, not reported; NA, not analyzed; Nap, not applicable.
a
Higher content in tissue of Swiss chard.
b
Higher content in leaves among different Swiss chard parts.
c
Higher content in stems/stalks/petioles among different Swiss chard parts.
12 M. GAMBA ET AL.
A (analyzed as b-carotene), our search did not find more
chemicals belonging to this group, demonstrating that meas-
ures for other types of vitamins in Swiss chard are lacking
in the scientific literature. Given the type of studies included
in this review, we could not assess their quality since there
are no validated tools for this purpose, and therefore our
results should be interpreted with caution.
Some of the included articles in this review have broadly
compared the nutritional and phytochemical composition of
Swiss chard with other leafy vegetables such as chicory,
green lettuce, red chard, spinach, and amaranth (Ali,
Khandaker, and Oba 2009; Colonna et al. 2016; Reif et al.
2013). In Table 4, we present the proximal composition of
Swiss chard leaves and its content of potassium, calcium,
magnesium, and total phenols and compare this information
with the leafy vegetables above mentioned as summarized by
Colonna et al. (2016). We also compare the b-carotene con-
tent reported for the same plants by Reif et al. (2013).
When the mentioned authors did not analyze the chemical
and nutritional profile of a vegetable, we used the data from
the USDA database (USDA 2019). Swiss chard has the low-
est values for carbohydrates (2158 mg/100 F.W.), and total
fat (99 mg/100 g F.W.) which makes it adequate for diets
attempting weight reduction. While protein had also the
lowest value (1500 mg/100 F.W.), the leaves of Swiss chard
ranked second in the fiber content after chicory leaves (4000
and 2430 mg/100 F.W., respectively). Regarding the mineral
content, the Swiss chard has the lowest values among the six
compared GLVs. However, the higher values reported for
potassium, magnesium and calcium in our review corres-
pond to those described by Mzoughi et al. (2019) and they
are at least three times larger than those founded by
Colonna et al. (2016). As for b-carotene, Swiss chard leaves
are positioned in third place after spinach and chicory (4.48,
7.28, and 4.88 mg/100 F.W., respectively). Lastly, Swiss chard
leaves have also the third-highest value of total phenols con-
tent (33.3 mg gallic acid/100 g D.W.) after red chard
(53.6 mg gallic acid/100 g D.W.) and spinach (49.3 mg gallic
acid/100 g D.W.) This comparison shows the potential of
Swiss chard as part of a healthy diet when consumed alter-
nately with other leafy vegetables.
There are several health benefits linked to the Swiss chard
bioactives found in this review. Experiments have shown
that flavonoids present in the extract of Beta vulgaris var.
cicla could have a hypoglycemic effect by inhibiting glucose
transporters, mainly through the action of quercetin (Song
et al. 2002). Vitexin and acacetin 8-C-b-D-glucopyranoside
showed superior antidiabetic activities in comparison with
Acarbose as a reference drug (Mohammed et al. 2019). An
alternative explanation for this property could be an inhibi-
tory effect on a-glucosidase and a-amylase activities
observed from an ethanol extract prepared from Swiss chard
leaves (Mzoughi et al. 2019). The antioxidant activity of
Swiss chard is well studied and similar to the conclusions by
Ali et al. (2009), it has been attributed to pigments present
in the leaves and stems like chlorophyll, betalains, and caro-
tenoids, but also to the flavonoids (Sacan and Yanardag
2010; Gennari et al. 2011; Moyo et al. 2017; Ivanovic et al.
2019) and non-flavonoids phenols/phenolics compounds
and to the ascorbic acid (Kim et al. 2004; Colonna et al.
2016; Ivanovic et al. 2019). Some of the specific actions
related to the antioxidant activity can be reviewed in beta-
lains, which have demonstrated an ability to protect human
red blood cells from oxidative hemolysis, to scavenge hypo-
chlorous acid produced by neutrophils during the inflamma-
tory response, to protect endothelial cells from the oxidation
processes related to inflammatory response and, to inhibit
lipid peroxidation of cell membranes in the blood (Ninfali
and Angelino 2013).
The phenolic amides present in the extract of Swiss chard
seeds have shown an anti-inflammatory effect demonstrated
in vitro by inhibiting nitric oxide synthase (Kim et al. 2003).
Betanin, a type of betalain, has also shown anti-inflamma-
tory activity throughout the inhibition of cyclooxygenase,
and prevention of the conversion of arachidonic acid into
chemical mediators of inflammation (Reddy, Alexander-
Lindo, and Nair 2005). Betalains also possess anticancer
activity by hindering the infiltration capacity of tumoral
cells, decreasing cell proliferation, and inducing apoptosis
(Ninfali and Angelino 2013; Esquivel 2016). Apigenin-
derived flavonoids found in leaves of Swiss chard, especially
vitexin, have proven to contribute to the anticancer activity
of this plant by inhibiting the proliferation of cancer cells
and inducing apoptosis (Ninfali et al. 2007; Gennari et al.
2011). Since excessive nitric oxide production has been
linked with cancer, the inhibitory activity of phenolic amides
on lipopolysaccharide could be another pathway to exert a
protective effect on carcinogenesis (Kim et al. 2003). The
antioxidant and anti-inflammatory activities related with
Swiss chard, its adequate unsaturated/saturated fatty acids
Table 4. Nutritional and phytochemical composition of the leaves of Beta vulgaris (Swiss chard) and other commonly consumed leafy vegetables (mg/
100 g F.W.).
Plant nutrient/phytochemical (reference) Swiss chard Chicory Green lettuce Red chard Spinach Amaranth, leaves
Proteins (Colonna et al. 2016) 1500 2100 1700 1900 1600 2460
a
Fat (Mzoughi et al. 2019) 99 300
a
150
a
200
a
390
a
330
a
Total carbohydrates (Mzoughi et al. 2019) 2158 4700
a
2870
a
3740
a
3630
a
4020
a
Total dietary fiber (Mzoughi et al. 2019) 2430 4000
a
1300
a
1600
a
2200
a
Not analyzed
Potasium (Colonna et al. 2016) 243.5 446.5 528.5 402 626.1 611
a
Magnesium (Colonna et al. 2016) 14.9 19.7 27.4 38.9 52.0 55
a
Calcium (Colonna et al. 2016) 12.1 29.9 22.9 16.4 25.4 215
a
b-Carotene (Reif et al. 2013) 4.48 4.88
b
2.55
b
3.64
a
7.28
b
Not analyzed
Total phenols
c
(Colonna et al. 2016) 33.3 34.9 21.7 53.6 49.3 Not analyzed
a
Source: U.S. Department of Agriculture (2019).
b
Highest value reported by Reif et al., 2013 for the vegetable.
c
(mg gallic acid/100 g D.W.).
CRITICAL REVIEWS IN FOOD SCIENCE AND NUTRITION 13
ratio and its high fiber, carotenoids, flavonoids, and potas-
sium content could play a role in the regulation of blood
pressure and of the lipid and glucose metabolism. Therefore,
the nutrients and phytochemicals present in Swiss chard
could contribute to the cardioprotective effect of this plant
as part of the leafy green vegetable family (Blekkenhorst
et al. 2018).
To our knowledge, this is the first systematic review on
the subject that critically appraised the literature following
an a priori designed protocol with clearly defined inclusion
and exclusion criteria. Using a systematic search in the data-
bases, we found only one classical review conducted by
Ninfali and Angelino (2013) evaluating the nutritional and
biological properties of Swiss chard. In contrast to system-
atic reviews, narrative reviews do not involve a systemic
search, and they are often focused on a subset of studies in
the chosen area based on the availability of the author selec-
tion. Therefore, they are more likely to experience selection
bias (Garg, Hackam, and Tonelli 2008; Uman 2011).
Conclusions
Swiss chard (Beta vulgaris L. var. cicla or flavescens) can be
considered a good source of fiber, betalains, flavonoids,
b-carotene, vitamin K, and minerals like potassium and
magnesium. Leaves and stems of the plant should be consid-
ered as part of a healthy diet. Further research is required
for sprouts as they are already being consumed as micro-
greens. It is also important to broaden the knowledge on
other phytochemical categories, like flavonoids, non-flavon-
oid phenols, minerals, terpenes, and vitamins, on all parts
that constitute the plant and in the flavescens variety.
Disclosure statement
H.K., W.B., and B. M. Metzger are scientists at Standard Process
Nutrition Innovation Center. Other authors have nothing to disclose.
Funding
This research was supported by Standard Process.
ORCID
Magda Gamba http://orcid.org/0000-0002-5703-2850
References
Adams, M. R., D. L. Golden, H. Chen, T. C. Register, and E. T.
Gugger. 2006. A diet rich in green and yellow vegetables inhibits
atherosclerosis in mice. The Journal of Nutrition 136 (7):1886–9. doi:
10.1093/jn/136.7.1886.
Ali, B., L. Khandaker, and S. Oba. 2009. Comparative study on func-
tional components, antioxidant activity and color parameters of
selected colored leafy vegetables as affected by photoperiods. Journal
of Food, Agriculture and Environment 7 (3).
Barba, F. J., M. J. Esteve, and A. Fr
ıgola. 2014. Chapter 11: Bioactive
components from leaf vegetable products. In Studies in natural
products chemistry, edited by Atta-Ur-Rahman , 321–46. New York,
NY: Elsevier.
Bas¸er, K. H. C., and F. J. F. Demirci. 2007. Fragrances: Chemistry, bio-
processing sustainability, chemistry of essential oils. New York, NY:
Springer.
Blekkenhorst, L. C., M. Sim, C. P. Bondonno, N. P. Bondonno, N. C.
Ward, R. L. Prince, A. Devine, J. R. Lewis, and J. M. Hodgson.
2018. Cardiovascular health benefits of specific vegetable types: A
narrative review. Nutrients 10 (5):595. doi: 10.3390/nu10050595.
Bozokalfa, M. K., B. Ya
gmur, T. K. As¸c¸ıo
gul, and D. Es¸iyok. 2011.
Diversity in nutritional composition of Swiss chard (Beta vulgaris
subsp. L. var. cicla) accessions revealed by multivariate analysis.
Plant Genetic Resources 9 (4):557–66. doi: 10.1017/
S1479262111000876.
Chen, G.-C., W.-P. Koh, J.-M. Yuan, L.-Q. Qin, and R. M. van Dam.
2018. Green leafy and cruciferous vegetable consumption and risk of
type 2 diabetes: Results from the Singapore Chinese Health Study
and meta-analysis. The British Journal of Nutrition 119 (9):1057–67.
doi: 10.1017/S0007114518000119.
Colonna, E., Y. Rouphael, G. Barbieri, and S. De Pascale. 2016.
Nutritional quality of ten leafy vegetables harvested at two light
intensities. Food Chemistry 199:702–10. doi: 10.1016/j.foodchem.
2015.12.068.
Cou
ee, I., C. Sulmon, G. Gouesbet, and A. El Amrani. 2006.
Involvement of soluble sugars in reactive oxygen species balance
and responses to oxidative stress in plants. Journal of Experimental
Botany 57 (3):449–59. doi: 10.1093/jxb/erj027.
Dietitians of Canada. 2020. All about Swiss chard. Accessed March 5,
2020. https://www.unlockfood.ca/en/Articles/Cooking-And-Food/
Vegetables-and-Fruit/All-About-Swiss-Chard.aspx.
Dinc¸ler, A., and T. Aydemir. 2001. Purification and Characterization of
Catalase from Chard (Beta vulgaris var. cicla). Journal of Enzyme
Inhibition 16 (2):165–75. doi: 10.1080/14756360109162366.
Dzida, K., and K. Pitura. 2008. The influence of varied nitrogen fertil-
ization on yield and chemical composition of Swiss chard (Beta vul-
garis L. var. cicla L.). Acta scientiarum Polonorum. Hortorum
cultus ¼Ogrodnictwo 73:15–24.
Esquivel, P. 2016. Betalains. In Handbook on natural pigments in food
and beverages, eds. R. Carle and R. M. Schweiggert, 81–99. Sawston,
UK: Woodhead Publishing.
Ferland, G., and J. A. Sadowski. 1992. Vitamin K1 (phylloquinone)
content of green vegetables: Effects of plant maturation and geo-
graphical growth location. Journal of Agricultural and Food
Chemistry 40 (10):1874–7. doi: 10.1021/jf00022a029.
Freeman, A. M., P. B. Morris, N. Barnard, C. B. Esselstyn, E. Ros, A.
Agatston, S. Devries, J. O’Keefe, M. Miller, D. Ornish, et al. 2017.
Trending cardiovascular nutrition controversies. Journal of the
American College of Cardiology 69 (9):1172–87. doi: 10.1016/j.jacc.
2016.10.086.
Gao, Z., X.-H. Han, and X.-G. Xiao. 2009. Purification and character-
isation of polyphenol oxidase from red Swiss chard (Beta vulgaris
subspecies cicla) leaves. Food Chemistry 117 (2):342–48. doi: 10.
1016/j.foodchem.2009.04.013.
Garg, A. X., D. Hackam, and M. Tonelli. 2008. Systematic review and
meta-analysis: When one study is just not enough. Clinical Journal
of the American Society of Nephrology: CJASN 3 (1):253–60. doi: 10.
2215/CJN.01430307.
Gennari, L., M. Felletti, M. Blasa, D. Angelino, C. Celeghini, A.
Corallini, and P. Ninfali. 2011. Total extract of Beta Vulgaris var.
Cicla seeds versus its purified phenolic components: Antioxidant
activities and antiproliferative effects against colon cancer cells.
Phytochemical Analysis: PCA 22 (3):272–9. doi: 10.1002/pca.1276.
Gil, M. I., F. Ferreres, and F. A. Tom
as-Barber
an. 1998. Effect of modi-
fied atmosphere packaging on the flavonoids and vitamin C content
of minimally processed Swiss chard (Beta vulgaris subspecies cycla).
Journal of Agricultural and Food Chemistry 46 (5):2007–12. doi: 10.
1021/jf970924e.
Hern
andez-Rodr
ıguez, P., L. P. Baquero, and H. R. Larrota. 2019.
Chapter 14: Flavonoids: Potential therapeutic agents by their antioxi-
dant capacity. In Bioactive compounds, eds. M. R. S. Campos,
265–88. Sawston, UK: Woodhead Publishing.
14 M. GAMBA ET AL.
Institute of Medicine (US) Panel on Micronutrients. 2001. Dietary ref-
erence intakes for vitamin A, vitamin K, arsenic, boron, chromium,
copper, iodine, iron, manganese, molybdenum, nickel, silicon, van-
adium, and zinc, ed. The National Academies. Washington, DC:
National Academies Press.
Ivanovic, L., I. Milasevic, A. Topalovic, D. Durovic, B. Mugosa, M.
Knezevic, and M. Vrvic. 2019. Nutritional and phytochemical con-
tent of Swiss chard from montenegro, under different fertilization
and irrigation treatments. British Food Journal 121 (2):411–25. doi:
10.1108/Bfj-03-2018-0142.
Kim, I., Y.-W. Chin, S. W. Lim, Y. C. Kim, and J. Kim. 2004.
Norisoprenoids and hepatoprotective flavone glycosides from the
aerial parts of Beta vulgaris var. cicla. Archives of Pharmacal
Research 27 (6):600–3. doi: 10.1007/BF02980156.
Kim, S., J. Chen, T. Cheng, A. Gindulyte, J. He, S. He, Q. Li, B. A.
Shoemaker, P. A. Thiessen, B. Yu, et al. 2019. PubChem 2019
update: Improved access to chemical data. Nucleic Acids Research 47
(D1):D1102–9. doi: 10.1093/nar/gky1033.
Kim, Y., M. S. Han, J. S. Lee, J. Kim, and Y. C. Kim. 2003. Inhibitory
phenolic amides on lipopolysaccharide-induced nitric oxide produc-
tion in RAW 264.7 cells from Beta vulgaris var. cicla seeds.
Phytotherapy Research: PTR 17 (8):983–5. doi: 10.1002/ptr.1232.
Kolota, E., K. Sowinska, and K. Czerniak. 2010. Yield and nutritional
value of Swiss chard grown for summer and autumn harvest.
Journal of Agricultural Science 2 (4):120. doi: 10.5539/jas.v2n4p120.
Kong, J.-M., L.-S. Chia, N.-K. Goh, T.-F. Chia, and R. Brouillard. 2003.
Analysis and biological activities of anthocyanins. Phytochemistry 64
(5):923–33. doi: 10.1016/S0031-9422(03)00438-2.
Kugler, F., S. Graneis, F. C. Stintzing, and R. Carle. 2007. Studies on
betaxanthin profiles of vegetables and fruits from the chenopodia-
ceae and cactaceae. Zeitschrift Fur Naturforschung. C, Journal of
Biosciences 62 (5–6):311–8. doi: 10.1515/znc-2007-5-601.
Kugler, F., F. Stintzing, and R. Carle. 2004. Identification of betalains
from petioles of differently colored Swiss chard (Beta vulgaris L. ssp.
cicla [L.] Alef. Cv. bright lights) by high-performance liquid chro-
matography-electrospray ionization mass spectrometry. Journal of
Agricultural and Food Chemistry 52 (10):2975–81. doi: 10.1021/
jf035491w.
Li, D., D. Sun-Waterhouse, Y. Wang, X. Qiao, Y. Chen, and F. Li.
2019. Interactions of some common flavonoid antioxidants. In
Encyclopedia of food chemistry, eds. L. Melton, F. Shahidi, and P.
Varelis, 644–9. Oxford, UK: Academic Press.
Mbaveng, A. T., R. Hamm, and V. Kuete. 2014. 19: Harmful and pro-
tective effects of terpenoids from African medicinal plants. In
Toxicological Survey of African Medicinal Plants, ed. V. Kuete,
557–76. New York, NY: Elsevier.
Miceli, A., and C. Miceli. 2014. Effect of nitrogen fertilization on the
quality of Swiss chard at harvest and during storage as minimally
processed produce. Journal of Food Quality 37 (2):125–34. doi: 10.
1111/jfq.12073.
Mohammed, H. S., M. Abdel-Aziz Marwa, S. Abu-Baker Marwa, M. S.
Amal, A. M. Mona, and A. G. Mosad. 2019. Antibacterial and
potential antidiabetic activities of flavone C-glycosides isolated from
Beta vulgaris subspecies cicla L. var. flavescens (Amaranthaceae) cul-
tivated in Egypt. Current Pharmaceutical Biotechnology 20 (7):
595–604. doi: 10.2174/1389201020666190613161212.
Moreira, M. d R., S. I. Roura, and C. E. del Valle. 2003. Quality of
Swiss chard produced by conventional and organic methods. LWT -
Food Science and Technology 36 (1):135–41. doi: 10.1016/S0023-
6438(02)00207-4.
Mori, N., T. Shimazu, H. Charvat, M. Mutoh, N. Sawada, M. Iwasaki,
T. Yamaji, M. Inoue, A. Goto, R. Takachi, et al. 2019. Cruciferous
vegetable intake and mortality in middle-aged adults: A prospective
cohort study. Clinical Nutrition (Edinburgh, Scotland) 38 (2):
631–43., doi: 10.1016/j.clnu.2018.04.012.
Morris, M. C., Y. Wang, L. L. Barnes, D. A. Bennett, B. Dawson-
Hughes, and S. L. Booth. 2018. Nutrients and bioactives in green
leafy vegetables and cognitive decline: Prospective study. Neurology
90 (3):e214–22. doi: 10.1212/WNL.0000000000004815.
Moyo, M., S. O. Amoo, A. O. Aremu, J. Gruz, M.
Subrtov
a, M.
Jaro
sov
a, P. Tarkowski, and K. Dole
zal. 2017. Determination of min-
eral constituents, phytochemicals and antioxidant qualities of
Cleome gynandra, compared to Brassica oleracea and Beta vulgaris.
Frontiers in Chemistry 5:128. doi: 10.3389/fchem.2017.00128.
Muka, T., M. Glisic, J. Milic, S. Verhoog, J. Bohlius, W. Bramer, R.
Chowdhury, and O. H. Franco. 2020. A 24-step guide on how to
design, conduct, and successfully publish a systematic review and
meta-analysis in medical research. European Journal of Epidemiology
35 (1):49–12. doi: 10.1007/s10654-019-00576-5.
Mzoughi, Z., H. Chahdoura, Y. Chakroun, M. C
amara, V. Fern
andez-
Ruiz, P. Morales, H. Mosbah, G. Flamini, M. Snoussi, and H.
Majdoub. 2019. Wild edible Swiss chard leaves (Beta vulgaris L. var.
cicla): Nutritional, phytochemical composition and biological activ-
ities. Journal of Food Research International 119:612–21. doi: 10.
1016/j.foodres.2018.10.039.
Ninfali, P., M. Bacchiocca, A. Antonelli, E. Biagiotti, A. M. Di
Gioacchino, G. Piccoli, V. Stocchi, and G. Brandi. 2007.
Characterization and biological activity of the main flavonoids from
Swiss chard (Beta vulgaris subspecies cycla). Phytomedicine 14 (2–3):
216–21. doi: 10.1016/j.phymed.2006.03.006.
Ninfali, P., and D. Angelino. 2013. Nutritional and functional potential
of Beta vulgaris cicla and rubra.Fitoterapia 89:188–99. doi: 10.1016/
j.fitote.2013.06.004.
Patel, D., S. Shukla, and S. Gupta. 2007. Apigenin and cancer chemo-
prevention: Progress, potential and promise. International Journal of
Oncology 30 (1):233–45.
Pokluda, R., and J. Kuben. 2002. Comparison of selected Swiss chard
(Beta vulgaris ssp. cicla L.) varieties. Horticultural Science 29 (3):
114–8. doi: 10.17221/4473-HORTSCI.
Pollock, R. L. 2016. The effect of green leafy and cruciferous vegetable
intake on the incidence of cardiovascular disease: A meta-analysis.
JRSM Cardiovascular Disease 5:2048004016661435. doi: 10.1177/
2048004016661435.
Pyo, Y.-H., T.-C. Lee, L. Logendra, and R. T. Rosen. 2004. Antioxidant
activity and phenolic compounds of Swiss chard (Beta vulgaris sub-
species cycla) extracts. Food Chemistry 85 (1):19–26. doi: 10.1016/
S0308-8146(03)00294-2.
Rana, M. K. 2016. Salad crops: Leaf-type crops. In Encyclopedia of food
and health, eds. B. Caballero, P. M. Finglas, and F. Toldr
a, 673–8.
Oxford, UK: Academic Press.
Reddy, M. K., R. L. Alexander-Lindo, and M. G. Nair. 2005. Relative
inhibition of lipid peroxidation, cyclooxygenase enzymes, and
human tumor cell proliferation by natural food colors. Journal of
Agricultural and Food Chemistry 53 (23):9268–73. doi: 10.1021/
jf051399j.
Reif, C., E. Arrigoni, H. Sch€
arer, L. Nystr€
om, and R. F. Hurrell. 2013.
Carotenoid database of commonly eaten Swiss vegetables and their
estimated contribution to carotenoid intake. Journal of Food
Composition and Analysis 29 (1):64–72. doi: 10.1016/j.jfca.2012.10.
005.
Sacan, O., and R. Yanardag. 2010. Antioxidant and antiacetylcholines-
terase activities of chard (Beta vulgaris L. var. cicla). Food and
Chemical Toxicology 48 (5):1275–80. doi: 10.1016/j.fct.2010.02.022.
Salehi, B., A. Venditti, M. Sharifi-Rad, D. KreRgiel, J. Sharifi-Rad, A.
Durazzo, M. Lucarini, A. Santini, E. B. Souto, E. Novellino, et al.
2019. The therapeutic potential of apigenin. International Journal of
Molecular Sciences 20 (6):1305. doi: 10.3390/ijms20061305.
Sener, G., O. Sac¸an, R. Yanarda
g, and G. Ayano
glu-D€
ulger. 2002.
Effects of chard (Beta vulgaris L. var. cicla) extract on oxidative
injury in the aorta and heart of streptozotocin-diabetic rats. Journal
of Medicinal Food 5 (1):37–42. doi: 10.1089/109662002753723205.
Singh, H., B. Dunn, and M. Payton. 2019. Hydroponic pH modifiers
affect plant growth and nutrient content in leafy greens. Journal of
Horticultural Research 27 (1):31–6. doi: 10.2478/johr-2019-0004.
Song, J., O. Kwon, S. Chen, R. Daruwala, P. Eck, J. B. Park, and M.
Levine. 2002. Flavonoid inhibition of sodium-dependent vitamin C
transporter 1 (SVCT1) and glucose transporter isoform 2 (GLUT2),
intestinal transporters for vitamin C and glucose. The Journal of
CRITICAL REVIEWS IN FOOD SCIENCE AND NUTRITION 15
Biological Chemistry 277 (18):15252–60. doi: 10.1074/jbc.
M110496200.
Stafford, H. A. 1994. Anthocyanins and betalains: Evolution of the
mutually exclusive pathways. Plant Science 101 (2):91–8. doi: 10.
1016/0168-9452(94)90244-5.
Strack, D., T. Vogt, and W. Schliemann. 2003. Recent advances in beta-
lain research. Phytochemistry 62 (3):247–69. doi: 10.1016/S0031-
9422(02)00564-2.
Tanaka, Y., N. Sasaki, and A. Ohmiya. 2008. Biosynthesis of plant pig-
ments: anthocyanins, betalains and carotenoids. The Plant Journal
54 (4):733–49. doi: 10.1111/j.1365-313X.2008.03447.x.
U.S. Department of Agriculture (USDA). 2019. FoodData Central—
USDA. Accessed July 17, 2020. http://fdc.nal.usda.gov/.
Uman, L. S. 2011. Systematic reviews and meta-analyses. Journal of the
Canadian Academy of Child and Adolescent Psychiatry ¼Journal de
l’Academie canadienne de psychiatrie de l’enfant et de l’adolescent 20
(1):57–9.
Wang,M.,J.Firrman,L.Liu,andK.Yam.2019.Areviewonflavonoid
apigenin: Dietary intake, ADME, antimicrobial effects, and interactions
with human gut microbiota. BioMed Research International 2019:1–18.
Article ID 7010467. doi: 10.1155/2019/7010467.
Yang, Y., W. Li, Y. Liu, Y. Li, L. Gao, and J.-J. Zhao. 2014. Alpha-
lipoic acid attenuates insulin resistance and improves glucose metab-
olism in high fat diet-fed mice. Acta Pharmacologica Sinica 35 (10):
1285–92. doi: 10.1038/aps.2014.64.
Zeller,W.,K.Rudolph,andH.H.Hoppe.1977.Effectofthe
Pseudomonas phaseolicola-toxin on the composition of lipids in leaves
of Swiss chard (Beta vulgaris L.) II. Changes in the fatty acid spectrum
of phospholipids and glycolipids. Journal of Phytopathology 89 (4):
296–305. doi: 10.1111/j.1439-0434.1977.tb02870.x.
16 M. GAMBA ET AL.