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Magnesium (Mg) is an essential mineral micronutrient in humans. Risks of dietary Mg deficiency are affected by the quantity of Mg ingested and its bioavailability, which is influenced by the consumption of other nutrients and ‘anti-nutrients’. Here, we assess global dietary Mg supplies and risks of dietary deficiency, including the influence of other nutrients. Food supply and food composition data were used to derive the amount of Mg available per capita at national levels. Supplies of Mg were compared with estimated national per capita average requirement ‘cut points’. In 2011, global weighted mean Mg supply was 613 ± 69 mg person–1 day–1 compared with a weighted estimated average requirement for Mg of 173 mg person–1 day–1. This indicates a low risk of dietary Mg deficiency of 0.26% based on supply. This contrasts with published data from national individual-level dietary surveys, which indicate greater Mg deficiency risks. However, individuals in high-income countries are likely to under-report food consumption, which could lead to overestimation of deficiency risks. Furthermore, estimates of deficiency risk based on supply do not account for potential inhibitors of Mg absorption, including calcium, phytic acid and oxalate, and do not consider household food wastage.
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Global magnesium supply in the food chain
Diriba B. Kumssa
A,B,C
, Edward J. M. Joy
A,B
, E. Louise Ander
B
, Michael J. Watts
B
,
Scott D. Young
A
, Andrea Rosanoff
D
, Philip J. White
E
, Sue Walker
C
, and Martin R. Broadley
A,F
A
School of Biosciences, University of Nottingham, Sutton Bonington, Loughborough, LE12 5RD, UK.
B
Centre for Environmental Geochemistry, British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK.
C
Crops For the Future, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih,
Selangor Darul Ehsan, Malaysia.
D
Center for Magnesium Education & Research, LLC, 13-1255 Malama St., Pahoa, HI 96778, USA.
E
The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK; Distinguished Scientist Fellowship Program,
King Saud University, Riyadh, Saudi Arabia.
F
Corresponding author. Email: martin.broadley@nottingham.ac.uk
Abstract. Magnesium (Mg) is an essential mineral micronutrient in humans. Risks of dietary Mg deciency are affected by
the quantity of Mg ingested and its bioavailability, which is inuenced by the consumption of other nutrients and anti-
nutrients. Here, we assess global dietary Mg supplies and risks of dietary deciency, including the inuence of other
nutrients. Food supply and food composition data were used to derive the amount of Mg available per capita at national levels.
Supplies of Mg were compared with estimated national per capita average requirement cut points. In 2011, global
weighted mean Mg supply was 613 69 mg person
1
day
1
compared with a weighted estimated average requirement for
Mg of 173 mg person
1
day
1
. This indicates a low risk of dietary Mg deciency of 0.26% based on supply. This contrasts
with published data from national individual-level dietary surveys, which indicate greater Mg deciency risks. However,
individuals in high-income countries are likely to under-report food consumption, which could lead to overestimation of
deciency risks. Furthermore, estimates of deciency risk based on supply do not account for potential inhibitors of Mg
absorption, including calcium, phytic acid and oxalate, and do not consider household food wastage.
Additional keywords: bioavailability, calcium, cereal, phytic acid, EAR.
Received 21 March 2015, accepted 10 June 2015, published online 5 October 2015
Introduction
Magnesium (Mg) is an essential mineral micronutrient in
humans, required for a variety of physiological functions. The
recommended nutrient intake for men 1965 years old is
260 mg day
1
(WHO and FAO 2004). A healthy adult contains
~24 g Mg, mainly in bone, muscle and soft tissues (Ebel and
Günther 1980; Elin 1987; Vormann 2003; WHO and FAO
2004). Magnesium is a cofactor in >350 enzymatic reactions,
with roles including protection from oxidative stress, and
metabolism of calcium (Ca), vitamin D and potassium (Ebel
and Günther 1980; Elin 1987; WHO and FAO 2004; Atkinson
et al.2009; Broadley et al.2012; Deng et al.2013; Das 2014;
Dibaba et al.2014; Rodríguez-Moran and Guerrero-Romero
2014). Deciency in Mg can manifest as metabolic syndrome
(Gartside and Glueck 1995; Hata et al.2013; Rosanoff and
Plesset 2013; Cosaro et al.2014;Juet al.2014; Panhwar et al.
2014), lower bone-mineral density (Orchard et al.2014),
premenstrual syndrome (Elin 1987), and attention decit
hyperactivity disorder (Blaszczyk and Duda-Chodak 2013).
Magnesium is obtained primarily from food sources, although
drinking and cooking water can make important contributions
depending on its hardness and the volume of water consumed
(Ong et al.2009). Median dissolved Mg concentrations of North
American spring, mineral, and groundwater from various regions
ranged from 0 to 130 mg L
1
(Azoulay et al.2001). Magnesium
contents of some commercially available bottled waters in
Europe were, for example, 36, 110, and 128 mg L
1
for Abbey
Well from the UK, Vichy Nouvelle from Finland, and Robacher
from Germany, respectively (Azoulay et al.2001). However,
unrened cereals, legumes and green leafy vegetables are the
primary dietary sources of Mg (Broadley and White 2010;
Blaszczyk and Duda-Chodak 2013). The bioavailability and
absorption of ingested Mg is affected by other nutrients and
anti-nutrients. For example, high concentrations of phytate in
cereal and legume seeds, and oxalate in some leafy vegetables,
can reduce Mg absorption through chelation in the gut (Brink
and Beynen 1991; Bohn et al.2004a). Addition of 1.5 mmol of
phytic acid (PA, in dodecasodium salt hydrate form) to white
bread reduced Mg absorption from 33% to 13% in human
feeding studies (Bohn et al.2004b). Similarly, Bohn et al.
(2004a) reported that Mg absorption from a meal containing
oxalate-rich spinach (Spinacia oleracea L.) was 27%, compared
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CSIRO PUBLISHING
Crop & Pasture Science
http://dx.doi.org/10.1071/CP15096
with 37% from a meal containing kale (Brassica oleracea L.),
which has a lower oxalate concentration. Fractional Mg
absorption of 44% (Sabatier et al.2003) and 35% (Marshall
et al.1976) has been reported in typical Western diets. A study on
rats showed that increased Ca intake led to reduced intestinal
absorption and renal re-absorption of Mg (Bertinato et al.
2014), although Palacios et al.(2013) reported no effects of
Ca intake on urinary Mg excretion in females aged 1115 years.
Nonetheless, absorption of Mg is under homeostatic control and
can increase when there is deciency of Mg in the human body
(Hansen et al.2014).
Dietary Mg intake and the prevalence of deciency risks can
be estimated from tissue biomarkers, food recall or food balance
sheets (FBSs) (Ford and Mokdad 2003; Broadley et al.2012;
Joy et al.2013,2014;Juet al.2014; Rodríguez-Moran and
Guerrero-Romero 2014; Kumssa et al.2015). However, the
accuracy of estimates of the prevalence of Mg deciency risks,
using tissue biomarkers, suffers from the lack of a reliable index
(Reinhart 1988; Hansen et al.2014; Ong et al.2014). Estimates
based on dietary intakes are preferred, particularly for wide-scale
assessment. Dietary recall studies suggest high risks of Mg
deciency. For example, ~60% of the USA population were
reported to consume Mg below an estimated average requirement
(EAR) of 330 mg person
1
day
1
for men aged 1930 based on the
National Health and Nutrition Examination Survey (NHANES)
24-h dietary recall in 1999 and 2000 (Ford and Mokdad 2003).
The EAR is the daily nutrient intake estimated to meet the
requirements of half of the healthy individuals in a given age-
and sex-specic population (IOM 2000). During the 200102
NHANES, 64% and 67% of men and women 19 years of age,
respectively, had Mg intake less than the EAR (Moshfegh et al.
2005, cited in Rosanoff 2010). Similarly, in the UK, the National
Diet and Nutrition Survey (NDNS) from 200809 to 201112
reported that 53% of females aged 1118 years, 14% of adults
aged 1964 years and 19% of males 65 years had dietary Mg
intakes below their lower reference nutrient intake (LRNI), as
measured using a 4-day diary dietary record (Bates et al.2014).
The LRNI is an intake level sufcient for <2.5% of the age- and
sex-specic population group and is 190 mg person
1
day
1
for
all people aged 1518 years and adult males. However,
dietary-recall or diary methods are known to be affected
by misreporting, especially under-reporting in developed
countries, and behavioural change (Bingham et al.1994; IOM
2000; Rennie et al.2004,2005,2007; Mirmiran et al.2006;
Liberato et al.2009; Archer et al.2013; Bates et al.2014;
Winkler 2014). In addition, dietary survey data are lacking in
many developing countries (Gibson 2005), as well as site-
specic and relevant food composition data to determine the
Mg concentrations of foods consumed (Joy et al.2014,2015;
Kumssa et al.2015).
Global-scale estimates of Mg supply and deciency risks
have not been reported. However, estimates of mean global
Ca supply in 2011 of 684 211 mg person
1
day
1
by Kumssa
et al.(2015) based on FBSs were similar to those of Imamura
et al.(2015), who estimated median Ca intakes of 611 mg
person
1
day
1
(third quintile range 553658) from a large
meta-analysis of milk consumption as a proxy for Ca intake,
based primarily on dietary recall data. The global risk of zinc (Zn)
deciency has been estimated, based on FBS supply, to be 16%
in 2011 by Kumssa et al.(2015) and 17% in 200307 by Wessells
and Brown (2012). In Africa, a mean continental Mg supply of
678 mg person
1
day
1
was estimated from FBSs and African
food composition data, with a 0.7% prevalence of deciency
risk (Joy et al.2014). The aims of the present study were (i)to
estimate the global risk of dietary Mg deciency based on food
supply, composition and demographics; and (ii) to assess the
potential impact of the supply of other components of human
diet that might affect the bioavailability of Mg.
Materials and methods
Methods are identical to those described previously for
estimating the risks of dietary Ca and Zn deciencies (Kumssa
et al.2015). Briey, secondary data for food supply, food
composition, demography and EAR for Mg were integrated
for 145 countries with populations >1 million by using food-
supply and demographic data from 1992 to 2011. The EAR cut-
point(EAR-CP) method was used to assess the prevalence of
Mg deciency risks.
Data sources
The four types of datasets required for this study were food
supply, food composition, the EAR for Mg, and national
demographic data. Per capita food supply data for 94 food
items were obtained from the Food and Agriculture
Organisation of the United Nations (FAO) Statistics Division
(FAOSTAT) website for the years 19922011 (FAO 2014).
Food composition data were obtained from the United States
Department of Agriculture (USDA) National Nutrient Database
for Standard Reference 26 (USDA SR26), which was released in
2013 (USDA 2013). The EARs for Mg were obtained from
the World Health Organisation (WHO) and FAO vitamin and
mineral requirements (WHO and FAO 2004). Demographic
data were obtained from the United Nations Department of
Economic and Social Affairs Population Division, Population
Estimates and Projection (United Nations 2013). Spatial
aggregation of countries was made based on FAO regional and
continental classication (http://faostat.fao.org/site/371/default.
aspx). Income level aggregation was obtained from the World
Data Bank, World Development Indicators in February 2015,
and countries are kept within the same group from 19922011
(http://databank.worldbank.org/data/reports.aspx?source=World-
Development-Indicators).
Magnesium supply
The 94 food items from the FAOSTAT food supply
(g person
1
day
1
) data (see Supplementary Materials table S1,
available on the Journals website) were matched (sensu
Stadlmayr et al.2011) with the Mg composition of fresh and/
or uncooked food commodities in the nutrient composition data.
The nutrient composition of food items was assumed not to
change with time or location. Per capita Mg supply from each
food item in each country was calculated by multiplying the
per capita food supply by its nutrient concentration. Magnesium
supply from each food commodity was summed within country
to obtain the per capita nutrient supply at a national level.
Magnesium supplies from fortication and supplements, and
drinking and cooking water were not accounted for in this study.
BCrop & Pasture Science D. B. Kumssa et al.
Magnesium intakes and requirements
Magnesium intakes were estimated as the mean per capita Mg
supply at a national level, with an inter-individual coefcient of
variation of 25% (Wessells and Brown 2012; Joy et al.2013).
The EAR for Mg is available according to age (~5-year
groupings) and gender classes (WHO and FAO 2004). As a
result, a national weighted EAR was calculated (WtdEAR)
(Eqn 1), using the population size in each age and gender
group for each country and year. For a given age or gender
group, the EAR was assumed to remain unchanged whereas the
WtdEAR varied with the population structure, which in turn
varied between countries and years. The WtdEAR for Mg is
hence assumed to approximate the per capita intake that fulls
the Mg requirements of half of the healthy individuals in a
population of a given country in a specic year:
WtdEAR ¼SEARgroup GroupPopðÞ
TotalPop ð1Þ
where EARgroup is the EAR for Mg of a given age or gender
group, GroupPop is the population size of a given age or gender
group, and TotalPop is the total population in a given year for a
given country.
Estimated average requirement cut-point
The prevalence of Mg-deciency risk was assessed using the
EAR-CP as described and used by Carriquiry (1999), Wuehler
et al.(2005), Joy et al.(2014) and Kumssa et al.(2015). The EAR-
CP method yields an estimate of the number of people in a given
country and year with intakes of Mg below the WtdEAR, which
is termed hereafter as the deciency risk. The EAR-CP method
has been applied with the following underlying assumptions:
(i) little correlation between requirement and intake; (ii) the
distribution of requirement is symmetrical around the EAR;
and (iii) variability in intake is greater than the variability in
requirement (IOM 2000).
Nutritional ratio
Dietary Ca and phytate, which represents the mixed salts of PA,
or myo-inositol hexakisphosphate, were calculated in a similar
manner to Mg. The PA and Ca data are those presented previously
(Kumssa et al.2015). The Ca : Mg ratio was calculated on a
gravimetric basis (Rosanoff 2010), whereas the Mg : PA ratio
was derived from the molar weights (Mg = 24.3 g mol
1
,PA=
660 g mol
1
) (Cheryan et al.1983).
Aggregating information
Spatial aggregation (i.e. regional, continental, global) and
income level aggregations (i.e. low income, lower middle
income, upper middle income, high income) of the mean and
standard deviation (s.d.) of Mg supply, WtdEAR, and deciency
risk, and Ca : Mg and Mg : PA ratios, were weighted by
the national population size. (See example in Eqns 2 and 3
below.) Aggregated information is presented as mean s.d.
unless specied.
Data analyses and visualisation
Datasets were compiled using Microsoft Excel 2013 and exported
to Microsoft Access 2013 (Microsoft Corp., Redmond, WA,
USA) to make a relational database. The database was queried
to extract the per capita Mg supply, and the WtdEAR for Mg.
The risk of Mg deciency during the 20-year period was then
calculated in Microsoft Excel. Visualisations and calculations
of descriptive statistics were carried out in Tableau Software
for desktop version 8.3 (Tableau Software, Seattle, WA, USA),
GraphPad Prism 6 (GraphPad Software, San Diego, CA, USA)
and ArcGIS 10.2.1 (Esri, Redlands, CA, USA). Country
boundaries for thematic mapping were obtained from the
GADM Global Administrative Areas database (http://gadm.
org/, Version 2; accessed January 2014).
Aggregation of (i) per capita mean (Eqn 2) and (ii) standard
deviation (Eqn 3) of supply (mg person
1
day
1
), WtdEAR
(mg person
1
day
1
), and deciency risk (%) of Mg at regional
level are presented as an example:
WtdMeanMgSupi¼SðMgSupjPCountryjÞ
SiPopulation ð2aÞ
where WtdMeanMgSup
i
is the weighted mean Mg supply in
region i, MgSup
j
is the Mg supply in country j, and PCountry
j
is
the population in country j.
WtdMgWtdMeanEARi¼SðMgWtdEARjPCountryjÞ
SiPopulation ð2bÞ
where WtdMgWtdMeanEAR
i
is the weighted mean MgWtdEAR
in region iand MgWtdEAR
j
is the per capita Mg WtdEAR in
country j.
WtdMgMeanDefRiski¼SðMgDefRiskjPCountryjÞ
SiPopulation ð2cÞ
where WtdMgMeanDefRisk
i
is the weighted Mg deciency risk
(%) in region i, and MgDefRisk
j
is the Mg deciency risk (%) in
country j.
SDiMgSupPerFood ¼
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
Si
jMgPerFoodjWtdMeanMgPerFoodi

2PCountryj

SiPopulation
s
ð3aÞ
where SD
i
MgSupPerFood
is the standard deviation of Mg supply
per food item in region i, MgPerFood
j
is the Mg composition of
a food item in country j in region i, WtdMeanMgPerFood
i
is
the weighted mean of Mg composition of a food item in region
i, PCountry
j
is the population of country j in region i, and
S
i
Population is the sum of population in region i.
SDiMgSup ¼ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
Si
jMgSupjWtdMeanMgSupi

2PCountryj

SiPopulation
s
ð3bÞ
where SD
i
MgSup
is the standard deviation of Mg supply in region i.
Global Mg supply in the food chain Crop & Pasture Science C
SDiMgWtdEAR ¼
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
Si
jMgWtdEARjWtdMgWtdMeanEARi

2PCountryj

SiPopulation
s
ð3cÞ
where SD
i
MgWtdEAR
is the standard deviation of Mg WtdEAR
in region i.
SDiMgDefRisk ¼
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
Si
jMgDefRiskjWtdMgMeanDefRiski

2PCountryj

Sri Population
s
ð3dÞ
where SD
i
MgDefRisk
is the standard deviation of Mg deciency
risk in region i.
Results
Magnesium supply and deciency risk
Globally, the weighted mean Mg supplies were 558 61
person
1
day
1
in 1992 and 613 69 mg person
1
day
1
in
2011, and the respective weighted mean WtdEARs were
166 3 and 173 3 mg person
1
day
1
. Consequently, 0.37%
and 0.26% of the population were likely at risk of dietary Mg
deciency in 1992 and 2011, respectively. Globally in 2011, the
number of people likely to be at risk of Mg deciency was
~14 million based on supply data (Fig. 1and Supplementary
table S2).
At a continental level in 2011, the supplies of Mg in Africa,
the Americas, Asia, Europe and Oceania, respectively, were
653 95, 556 45, 615 69, 627 54 and 552 4mg
person
1
day
1
; the WtdEARs for Mg were 159 3, 174 3,
174 3, 180 1 and 178 1 mg person
1
day
1
; and the risks
of Mg deciency were 0.19%, 0.33%, 0.26%, 0.24% and 0.33%
(Supplementary table S3). In Africa, the Americas, Asia, Europe
and Oceania, respectively, the number of people at risk of Mg
deciency in 2011 was 1.2, 2.8, 8.6, 1.6 and 0.1 million
(Supplementary table S3). Regionally in 2011, Mg supplies
ranged from 492 34 person
1
day
1
for Southeast Asia to
848 114 mg person
1
day
1
for Northern Africa. The risk of
Mg deciency in 2011 ranged from 0.08% in Northern Africa to
0.64% in Caribbean (Fig. 2and Supplementary table S4). At a
country level, the supply of Mg in 2011 ranged from 340 to
944 mg person
1
day
1
(Fig. 3and Supplementary table S5). In
1992, the supplies of Mg ranged from 460 93 mg
person
1
day
1
in low-income countries to 594 57 mg
person
1
day
1
in high-income countries, with respective
deciency risks of 0.75% and 0.27%. In 2011, the supplies of
Mg ranged from 549 103 mg person
1
day
1
in low-income
countries to 679 107 mg person
1
day
1
in upper middle-
income countries, with respective Mg deciency risks of
0.35% and 0.21% (Fig. 4and Supplementary table S6).
Sources of dietary magnesium
Typically, 4080% of dietary Mg in all regions and years
originated from cereals (Fig. 5). For example, in 2011, 79% of
dietary Mg in Afghanistan originated from wheat, 64% in
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
700
Mean Mg supply Mean Mg WtdEAR Mean Mg deficiency risk
M
g
deficienc
y
risk (%)
600
500
400
0.6
0.5
0.4
0.3
0.2
0.1
0
Mg supply & WtdEAR (mg capita–1 day–1)
300
200
100
0
Reference year
Fig. 1. Global weighted mean magnesium (Mg) supply, weighted estimated average requirement (WtdEAR) and deciency risk
between 1992 and 2011. Capped lines are standard deviation.
DCrop & Pasture Science D. B. Kumssa et al.
Africa
800
600
400
200
0
1.5
1.0
0.5
0
1995
2000
2005
2010
1995
2000
2005
Year Year Year Year Year
2010
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
Americas Asia Europe Oceania
Mg supply (mg capita–1 day–1)Mg deficiency risk (%)
Fig. 2. Regional population-weighted mean magnesium (Mg) supply and deciency risk between 1992 and 2011. Horizontal broken lines represent the
population-weighted mean weighted estimated average requirement.
(a)
(b)
(c)
(d)
Mg supply (mg capita–1 day–1) Mg supply (mg capita–1 day–1)
293–450
<0.5 1.5–3.2
0.5–1.5 No data
339–450 550–650
450–550 650–944
No data
450–550
550–650 No data
650–1019
Mg deficiency risk (%)
<0.5 1.5–1.54
0.5–1.5 No data
Mg deficiency risk (%)
Fig. 3. National magnesium (Mg) supplies in (a) 1992 and (c) 2011, and Mg deciency risks in (b) 1992 and (d) 2011.
Global Mg supply in the food chain Crop & Pasture Science E
Bangladesh from rice, and 63% in Zambia from maize
(Supplementary table S7). In high-income countries, wheat
provided 43% of dietary Mg, while aquatic plants, nuts,
potatoes and vegetables contributed 6% each to dietary Mg
(Fig. 6).
Nutritional ratios
Globally, the Ca : Mg supply ratios were 0.96 0.49 in 1992
and 1.11 0.38 in 2011 (Supplementary table S2). In 2011 at a
continental level, the Ca : Mg ratios were 0.72 0.24 in Africa,
1.55 0.41 in the Americas, 1.01 0.23 in Asia, 1.57 0.21 in
Europe and 1.69 0.08 in Oceania (Supplementary table S3).
In 2011, regionally, the Ca : Mg ratios ranged from 0.61 0.1
in Western Africa to 2.00 0.08 in Northern America
(Supplementary table S4), and at a country level from 0.36 to
2.15 (Fig. 7and Supplementary table S5). For low and high
income countries, respectively, Ca : Mg ratios ranged from
0.64 0.20 to 1.72 0.55 in 1992 and from 0.71 0.23 to
1.64 0.32 in 2011 (Fig. 4and Supplementary table S6).
Global Mg : PA ratios were 8.00 1.53 in 1992 and
7.99 1.48 in 2011 (Supplementary table S2). At a continental
level, the Mg : PA ratios in 2011 were 6.81 1.26 in Africa,
7.97 1.59 in the Americas, 8.00 1.33 in Asia, 9.49 0.94 in
Europe and 8.91 0.68 in Oceania (Supplementary table S3).
Regionally, the Mg : PA ratios in 2011 ranged from 5.65 0.49 in
Central America to 11.18 0.65 in Central Asia (Supplementary
table S4). At a country level, the Mg : PA ratios ranged from 4.67
to13.49in2011(Fig.7and Supplementary table S5). For low
and high income countries, respectively, the Mg:PA ratios
ranged from 6.02 0.8 to 9.49 1.03 in 1992 and from
6.11 0.96 to 9.21 0.87 in 2011 (Fig. 4and Supplementary
table S6).
Discussion
The global prevalence of dietary Mg-deciency risk, based on
food supply data, was <1% during 19922011 and decreased
over this period. In 2011, 14 million people globally were likely
at risk of dietary Mg deciency, based on these data. The
decreasing trend in the risk of dietary Mg deciency is likely
due to the overall increase in global food production, especially
cereals, which are the major sources of dietary Mg (Welch and
Graham 1999; Pingali 2012; FAO, IFAD, WFP 2014). This is in
agreement with published estimates of dietary Mg-deciency
risks for Africa (Broadley et al.2012; Joy et al.2013,2014).
The risk of dietary Mg deciency is greater in low-income
countries.
Estimates of the risk of dietary Mg deciency based on dietary
recalls are much greater than the above estimates (1453%,
UK NDNS data, Bates et al.2014;6467%, NHANES data,
Moshfegh et al. 2005, cited in Rosanoff 2010). Those reports
contrast markedly with the results presented here, which suggest
that the risks of dietary Mg deciency for USA and UK in 2011
were 0.32% and 0.25%, respectively. This discrepancy might be
attributed in part to misreporting of dietary intakes by respondents
participating in dietary-recall surveys (Bingham et al.1994; IOM
2000; Rennie et al.2004,2005,2007; Mirmiran et al.2006;
Liberato et al.2009; Archer et al.2013; Bates et al.2014; Winkler
2014). For example, energy intake was under-reported from 24-h
dietary recall by 15% in Brazil (Avelino et al.2014), >25% in the
UK (Rennie et al.2007), and 67% for men and 59% for women in
the USA (Archer et al.2013). Galan et al.(2002) reported dietary
Mg intake in France for adult female (3560 years) and male
(4560 years) tapwater drinkers of 284 and 377 mg day
1
,
respectively, using 24-h recall surveys. Charlton et al.(2005)
reported dietary Mg intakes in Cape Town, South Africa, of 228,
700
Low income High income
Lower middle income Upper middle income
(a)(c)
(b)(d)
600
500
400
300
200
100
0
Mg supply (mg capita–1 day–1)
Mg deficiency risk (%)
Ca : Mg ratioMg : PA ratio
0.8
0.6
0.4
0.2
1994 1996 1998 2000 2002 2004 2006 2008 2010
Year Year
1994
0
2
4
4
3
2
1
0
6
8
10
1996 1998 2000 2002 2004 2006 2008 2010
0
Fig. 4. Population-weighted mean (a) magnesium (Mg) supply (broken horizontal line represents weighted estimated
average requirement); (b)deciency risk; (c) calcium (Ca) : Mg ratio (broken horizontal line is optimum Ca : Mg ratio); and
(d) Mg : phytic acid (PA) ratio between 1992 and 2011 according to income.
FCrop & Pasture Science D. B. Kumssa et al.
60
80
Eastern Africa(a)
(b)
(c)
(d)
Middle Africa Northern Africa Southern Africa Western Africa
Caribbean
Central Asia Eastern Asia
Eastern Europe
South-Eastern Asia Southern Asia
Southern Europe
Western Asia
Western Europe Australia and New Zealand
Central America Northern America
Northern Europe
Southern America
40
20
Dietary Mg contribution (%)Dietary Mg contribution (%)Dietar y Mg contribution (%)Dietary Mg contribution (%)
0
Year Year Year Year Year
Year Year Year Year
60
80
40
20
0
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
Year Year Year Year Year
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
Year Year Year Year Year
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
1995
2000
2005
2010
60
80
40
20
0
60
80
40
20
0
Fig. 5. Regional temporal trends in the percentage contribution of food groups to magnesium (Mg) supplies between 1992 and 2011 Data are shown for
(a) Africa, (b) the Americas, (c) Asia, (d) Europe and Oceania.
Global Mg supply in the food chain Crop & Pasture Science G
261, and 285 mg person
1
day
1
for mixed ancestry, black and
white ethnic groups, respectively, using 24-h recall surveys of
men and women aged 2065 years. These reported Mg intakes
are less than half of our estimates of 600 and 637 mg
person
1
day
1
of Mg supply in 2011 for France and South
Africa, respectively. By contrast, Ca supply calculated from
FBS (Kumssa et al.2015) was only 15% greater than that
estimated from dietary-recall data using milk as a proxy
(Imamura et al.2015).
Other caveats in this study include the lack of spatial and
temporal resolution in food composition data. Thus, Mg
concentration data for foods were sourced from the USDA-
SR26 food composition database, which is centred on foods
grown in North America (USDA 2013). Thus, the impact of
different crop varieties, soil types and agronomy (White and
Broadley 2009) between and within countries and over time
cannot be accounted for in the present study (White and
Broadley 2005;Davis2009). Therefore, the estimated risks of
dietary Mg deciency will be compromised by the absence of
relevant, reliable and up-to-date food composition data, which
require more detailed local study. For example, in a recent analysis
of dietary duplicates in Malawi from a single day (Hurst et al.
2013), mean and median Mg intakes were 418 and 353 mg
person
1
day
1
(n= 114). This is in broad agreement with the
low estimated risk of Mg deciency based on FBS supply data,
but is still lower than the Mg supply estimate of 530 mg
person
1
day
1
in the present study. However, large differences
were observed in Mg intake from those living in Zombwe
Extension Planning Area (predominantly non-calcareous soil;
n= 56) and Mikalango Extension Planning Area (predominantly
calcareous soil; n= 58). Median Mg intake in Zombwe was
267 mg person
1
day
1
, compared with 538 mg person
1
day
1
in Mikalango (unpublished data collected during the study of
Hurst et al.2013). These differences were due primarily to
differences in cereal Mg concentrations between soil types
(Broadley et al.2012;Joyet al.2015) and to dietary choices.
For example, sorghum grain had a higher Mg concentration than
maize grain and it was consumed more often in Mikalango.
Other methodological weaknesses in determining Mg
deciency risks from food-supply data include effects of food
processing and food waste at the household level. In terms of
food processing, the USDA food composition table (USDA
2013) shows that enriched white bread-wheat our (25 mg
100 g
1
) contains much less Mg than whole-grain wheat our
(137 mg 100 g
1
). Thus, if food processing is not captured
accurately by FBS data, then further discrepancies in
estimates of Mg deciency risks could arise from supply-
based methods v. dietary recall. Food balance sheets also
do not capture waste at the household level and will therefore
overestimate consumption (FAO 2001). In developed
countries, household food wastage occurs from unplanned
purchases, behaviour and best-before-dates(Partt et al.
Aquatic Plants
Nuts
Potatoes
Vegetables
Wheat
Others
Cassava
Cereals, Other
Maize
Millet
Plantains
Pulses, Other
Rice
Sorghum
Wheat
Yams
Others
Cassava
Maize
Rice
Sorghum
Wheat
Yams
Others
Maize
Millet
Rice
Rye
Sorghum
Vegetables
Wheat
Others
13%
6%
(a)(b)
(c)(d)
6%
7%
18%
8%
5%
6%
19%
10%
29%
9%
6%
20%
12%
8%
39%
12%
7%
9%
6%
7%
5% 43%
6% 6%
6%
6%
33%
16%
15%
2%
Fig. 6. Percentage contribution of food items to total dietary magnesium (Mg) supplies in (a) low-income, (b) lower middle-income,
(c) upper middle-income, and (d) high-income countries. Others represents all food commodities that individually contribute <5% to total
dietary Mg in 2011.
HCrop & Pasture Science D. B. Kumssa et al.
2010;Erikssonet al.2012). Gustavsson et al.(2011) estimated
food waste in Europe and North America was 95115 kg
person
1
year
1
,comparedwith611 kg person
1
year
1
in sub-
Saharan Africa, and South and Southeast Asia. Forcereals, 225%
of the initial production is wasted at household level (Gustavsson
et al.2011). Given that cereals are the major source of dietary
Mg (Fig. 6), quantifying deciency based on FBSs is likely
to systemically underestimate Mg deciency risk. Drinking and
cooking water can also have an important contribution to Mg
nutrition, where water Mg concentrations are sufciently elevated
(Marier 1982;Rosanoff2013;Kanadhiaet al.2014), but this
was not assessed in this study.
The risk of Mg deciency is determined not only by Mg
intake but also by the proportion of other nutrients and anti-
nutrients (e.g. Ca, PA, oxalate, bre, saturated fat, etc.) in the gut
that affect its bioavailability (Vitale et al.1957; Seeling 1964;
Reinhold et al.1976; Cheryan et al.1983; Pallauf et al.1998;
Coudray et al.2003; Bohn et al.2004b). The dietary Ca : Mg
ratios based on dietary recall were 2.9 in France (Galan et al.
2002) and 1.9 in South Africa (Charlton et al.2005), compared
with our estimates of 1.69 and 0.65, respectively, in 2011. Dai
et al.(2007) reported that a Ca : Mg ratio >2.8 may affect Mg
absorption. In our study, the Ca : Mg ratio from food supply
was generally <2; however, processing of cereals is likely to
result in larger reductions in intake of Mg than of Ca, thereby
increasing Ca : Mg ratios at the intake level. For example, the
concentration of Mg in whole grain wheat was reduced by 82%,
whereas Ca was reduced by 56% when processed into un-
enriched bread our (USDA 2013). Thus, in countries where
Ca : Mg supply ratio approaches or exceeds ~2, the impact of
Ca and other nutrients on Mg bioavailability needs to be
investigated further. Interestingly, Seeling (2006) has argued
that the rise in recommended Ca intake could affect Mg
absorption if there is not a concurrent increase in Mg. High
concentrations of PA in cereals and legumes, and oxalates in
some green leafy vegetables, can also reduce Mg absorption in
the gut because of chelation (Brink and Beynen 1991; Bohn
et al.2004a). In high-income countries, aquatic plants provided
6% of the total dietary Mg (Fig. 6), indicating the important
potential role of underutilised crops in human dietary Mg
nutrition. The estimated Mg : PA molar ratio in all countries
was 514, which is in the range observed to affect the
absorption of Mg (Cheryan et al.1983). At a global scale, our
results indicate that while Mg supply from agricultural
production is likely to be sufcient to meet the requirements of
the population, the prevalence of high Mg : PA ratios in diets
around the world requires further study to determine the extent
to which Mg absorption might be impaired.
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... Magnesium (Mg) and calcium (Ca) are two essential macronutrients required for the growth and development of higher plants and for human dietary health (Karley and White, 2009;Kumssa et al., 2015aKumssa et al., , 2015b. Unfortunately, the topic of Mg and Ca nutrition in intensive agricultural production has been consistently neglected in recent years, resulting in a commonly occurring problem of Mg and Ca deficiency in soil and plant systems, as well as Mg and Ca concentrations in edible parts of various crops, vegetables, and fruits being severely reduced (White and Broadley, 2009). ...
... Unfortunately, the topic of Mg and Ca nutrition in intensive agricultural production has been consistently neglected in recent years, resulting in a commonly occurring problem of Mg and Ca deficiency in soil and plant systems, as well as Mg and Ca concentrations in edible parts of various crops, vegetables, and fruits being severely reduced (White and Broadley, 2009). Dietary Mg and Ca deficiency are linked to multiple human diseases, such as hypertension, cardiovascular risk, diabetes mellitus, and numerous skeletal and nonskeletal disorders (Kisters and Gröber, 2013;Kumssa et al., 2015aKumssa et al., , 2015b. Therefore, improving plant Mg and Ca nutrition is critical for agricultural production and human health. ...
Article
Magnesium (Mg) and calcium (Ca) are two essential macronutrients in plants; however, the characteristics of Mg and Ca concentrations in organ, subcellular and chemical forms and their relationships in citrus plants, especially under varying Mg supply, are not well understood. In this study, Citrus sinensis seedlings (cv. Xuegan) were cultivated in conditions of Mg deficiency (0 mmol Mg2+ L-1) and Mg sufficiency (2 mmol Mg2+ L-1) to investigate the responses of Mg and Ca homeostasis in different organs and fractions. Compared with Mg sufficiency, Mg deficiency significantly decreased root and shoot growth, with the shoot biomass reduction of branch organs was greater than that of parent organs. In addition to increasing the Ca concentration in the parent stem and lateral root organs, Mg deficiency significantly decreased the concentrations and accumulations of Mg and Ca in citrus seedlings, further altering their distribution in different organs. More than 50% of Ca and Mg were sequestrated in the cell wall and soluble fractions, respectively, with Mg concentration decreasing by 15.4% in roots and 46.9% in leaves under Mg deficiency, while Ca concentration decreased by 27.6% in roots and increased by 23.6% in parent leaves. Approximately 90% of Mg exists in inorganic, water-soluble, and pectate and protein-bound forms, and nearly 90% of Ca exists in water-soluble, pectate and protein-bound, phosphate and oxalate acid forms. Except for the decreased inorganic Mg in roots and water-soluble Mg and Ca in leaves, Mg deficiency increased the proportions of Mg and Ca in all chemical forms. However, Mg deficiency generally increased the Ca/Mg ratio in various organs, subcellular and chemical forms, with negative relationships between Mg concentration and Ca/Mg ratio, and the variations of Mg and Ca were highly separated between Mg supply and organs. In conclusion, our results provide insights into the effects of Mg supply on Mg and Ca homeostasis in citrus plants.
... Group Age AIK (mg capita −1 day −1 ) AIK_06 AIK_19 AIK_EU WHO Infants 0-6 months 400 400 7-12 months 700 860 750 Children 1-3 years 3000 2000 1100 4-8 years 3800 2300 1800 Males 9-13 years 4500 2500 2700 14-18 years 4700 3000 3500 3510 19-30 years 4700 3400 3500 3510 31-50 years 4700 3400 3500 3510 51-70 years 4700 3400 3500 3510 >70 years 4700 3400 3500 3510 Females 9-13 years 4500 2300 2700 14-18 years 4700 2300 3500 3510 19-30 years 4700 2600 3500 3510 31-50 years 4700 2600 3500 3510 51-70 years 4700 2600 3500 3510 >70 years 4700 2600 3500 3510 Pregnancy 14-18 years 4700 2600 3500 19-30 years 4700 2900 3500 31-50 years 4700 2900 3500 Lactation 14-18 years 5100 2500 4000 19-30 years 5100 2800 4000 31-50 years 5100 2800 4000 The prevalence of K deficiency in populations with median K supply greater or equal to the AI is likely to be low; however, the inverse cannot be assumed where the median K intake is less than the AI [21], and this limits the ability to assess the adequacy of population K intakes. This contrasts with other mineral micronutrients which have RDAs and Estimated Average Requirement (EAR) values defined, from which the prevalence of inadequate dietary intakes and risk of deficiency can be estimated [9,12,[21][22][23]. ...
... With the availability of more evidence, the AI values may be updated again. In the future, it may be possible to propose the Estimated Average Requirement (EAR) and Recommended Daily Allowance (RDA) reference values, which will enable the estimation of the prevalence of inadequate dietary K supplies at national levels using an adapted EAR cut-point methodology, as described previously for other micronutrients [22,23,31,32]. ...
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Background: Potassium (K) is an essential mineral and major intracellular electrolyte involved in the regulation of blood pressure, muscle contraction and nerve transmission in humans. Major dietary sources of K include fruits and vegetables, starchy roots and tubers, and whole grains. The aim of this study was to assess and report: (i) the sufficiency of K in national food systems globally, (ii) to quantify the contribution from food groups, and (iii) to explore spatial and temporal trends in the period of 1961–2017. Methods: Food supply and demography (1961–2017), K composition and K requirement data were combined to estimate per capita human dietary supplies of potassium (DSK), adequate intake of K (AIK) and K sufficiency ratio (KSR) at national, regional, continental and global levels. Results and Discussion: Globally, the mean ± SD. DSK (mg capita−1 d−1) increased from 2984 ± 915 in 1961 to 3796 ± 1161 in 2017. There was a wide range in DSK between geographical regions and across years, with particularly large increases in east Asia, where DSK increased from 5000 mg capita−1 day−1. Roots and tubers contributed the largest dietary source of K, providing up to 80% of DSK in most regions. At the global level, throughout the 57-year period, the population-weighted KSR was 1 based on the 2019 National Academies of Science and the 2016 European Union AIK recommendation. While KSR ≥1 shows sufficiency of DSK, KSR
... Biofortification of food crops with Mg to improve human nutrition is becoming a popular topic because of increasing number of reports indicating reduced dietary intake of Mg, especially in western countries. However, there are also reports (based on food supply and composition) suggesting a minimal risk of deficient dietary Mg intake in many countries (Kumssa et al. 2015). Consumption of diets with high Ca:Mg ratio was discussed at the Symposium as an important factor contributing to impaired human Mg nutrition, especially in USA. ...
... Hidden hunger of micronutrient particularly zinc in soils limits the crop productivity and nutritional quality of foods, which in turns affects plant-animal-human nutrition and health. Intensive farming with exhaustive high yielding crop varieties under protected cultivation and imbalanced fertilization not only reduces the crop productivity, but also reduces the nutritional quality of crop produce, which consequently contributes to human malnutrition (Kumssa et al., 2016;Van Pamel et al., 2020). Zinc release and bioavailability in soil and growing media is an important process affected by zinc reactivity, which is influenced by zinc speciation, solution composition and nature of growing media (Shi et al., 2008;Peng et al., 2017). ...
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Aim: To assess the zinc release from soils and various soilless growing media mixtures comprising different organic manures mixed at various proportions and to understand the kinetic behaviour of Zn release. Methodology: An incubation study was conducted to examine the time dependent release of zinc from soil and different growing media mixtures of Cocopeat (CP), Vermicompost (VC), Farm Yard Manure (FYM), Pressmud (PM), Vermiculite (VL) and Composted coco peat (CCP) by adding various levels of ZnSO4 (0, 12.5, 25, 37.5 and 50 kg ha-1) for 60 days. The Zn release at required time interval was quantified in soil and growing media mixtures. Results: Higher zinc release was recorded with growing media mixture of Cocopeat + Vermicompost + Pressmud (1:1:1) as compared to other mixtures. The release was linear up to 30 days and dropped at 45 days then increased. Fitting of various kinetic equations for better understanding of zinc release satisfactorily accounted (R2, 0.975 to 0.998, at p ≤0.05) by the zero order kinetic equation. Higher half-life time for Zn release (t1/2) was noticed with Soil + FYM and Cocopeat + Vermicompost + Pressmud mixtures, which confirmed their suitability. A significant negative correlation between pH, C:N ratio with Zn availability as well as linear decrease in organic carbon content prompted zinc release. Interpretation: Based on the amount of zinc released and grouping through principal component analysis with hierarchical clustering, a mixture of Cocopeat +Vermicompost +Pressmud at 1:1:1 was the best growing media mixture. Higher initial zinc availability and half-life time (t1/2) for zinc release makes it more efficient and best growing media mixture to sustain Zn supply to crops for a longer period of time.
... Malabsorption syndromes, disorders of the kidney tubules, alcohol abuse, rare genetic diseases and some therapeutic regimens cause Mg deficiency. However, an insufficient dietary intake is the frequent root of an overlooked low Mg status in western populations [5,6,7,8]. The intent of this scoping review is to offer insights into the mechanisms involved in reducing Mg availability in the food chain. ...
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Magnesium is essential in plants where it is associated with chlorophyll pigments and serves as a cofactor of enzymes implicated in photosynthesis and metabolism. It is an essential nutrient for animals, involved in hundreds metabolic reactions and crucial for the biological activity of ATP. Not surprisingly, magnesium deficiency is detrimental for the health of plants and animals. In humans, subclinical magnesium deficiency is common and generates chronic inflammation, which is the common denominator of a wide range of mental and physical health problems from metabolic diseases to cognitive impairment, from osteopenia and sarcopenia to depression. It is ascertained that magnesium content in fruits and vegetables dropped in the last fifty years, and about 80% of this metal is lost during food processing. As a consequence, a large percentage of people all over the world does not meet the minimum daily magnesium requirement. In this scoping review, we summarize how agronomic and environmental factors, including global warming, affect magnesium content and availability in the soil and, consequently, in the food chain, with the aim of attracting the interest of botanists, agronomists, animal and human nutritionists and physicians to work on a strategy that grants adequate magnesium intake for everybody.
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Working across agriculture–nutrition domains, nutrition balance sheets provide farm-to-fork estimates of the availability of dietary nutrients for human consumption.
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Adequate supplies of healthy foods available in each country are a necessary but not sufficient condition for adequate intake by each individual. Here we provide complete nutrient balance sheets that account for all plant-based and animal-sourced food flows from farm production through trade to non-food uses and waste in 173 countries from 1961 to 2018. We track 36 bioactive compounds in all farm commodities recorded by the Food and Agriculture Organization of the United Nations, accounting for nutrient-specific losses in processing and cooking as well as bioavailability. We compare supply with requirements given each country’s age–sex distribution and find that the adequacy of food supplies has increased but often remains below total needs, with even faster rise in energy levels and lower density of some nutrients per calorie. We use this nutrient accounting to show how gaps could be filled, either from food production and trade or from selected biofortification, fortification and supplementation scenarios for nutrients of concern such as vitamin A, iron and zinc. Farm to fork supply of bioactive compounds in food is traced for 173 countries over 60 years, and the availability of nutrients is compared with nutrient requirements of populations at age–sex distributions. This accounting method identifies nutrient gaps to be filled from from food production, trade, fortification and supplementation scenarios.
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Phytate or phytic acid (PA), is a phosphorus (P) containing compound generated by the stepwise phosphorylation of myo-inositol. It forms complexes with some nutrient cations, such as Ca, Fe and Zn, compromising their absorption and thus acting as an anti-nutrient in the digestive tract of humans and monogastric animals. Conversely, PAs are an important form of P storage in seeds, making up to 90% of total seed P. Phytates also play a role in germination and are related to the synthesis of abscisic acid and gibberellins, the hormones involved in seed germination. Decreasing PA content in plants is desirable for human dietary. Therefore, low phytic acid (lpa) mutants might present some negative pleiotropic effects, which could impair germination and seed viability. In the present study, we review current knowledge of the genes encoding enzymes that function in different stages of PA synthesis, from the first phosphorylation of myo-inositol to PA transport into seed reserve tissues, and the application of this knowledge to reduce PA concentrations in edible crops to enhance human diet. Finally, phylogenetic data for PA concentrations in different plant families and distributed across several countries under different environmental conditions are compiled. The results of the present study help explain the importance of PA accumulation in different plant families and the distribution of PA accumulation in different foods.
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Magnesium (Mg) and calcium (Ca) are essential mineral nutrients poorly supplied in many human food systems. In grazing livestock, Mg and Ca deficiencies are costly welfare issues. Here, we report a Brassica rapa loss-of-function schengen3 (sgn3) mutant, braA.sgn3.a-1, which accumulates twice as much Mg and a third more Ca in its leaves. We mapped braA.sgn3.a to a single recessive locus using a forward ionomic screen of chemically mutagenised lines with subsequent backcrossing and Linked-Read sequencing of second back-crossed, second filial generation (BC2F2) segregants. Confocal imaging revealed a disrupted root endodermal diffusion barrier, consistent with SGN3 encoding a receptor-like kinase required for normal formation of Casparian strips, as reported in thale cress (Arabidopsis thaliana). Analysis of the spatial distribution of elements showed elevated extracellular Mg concentrations in leaves of braA.sgn3.a-1, hypothesised to result from preferential export of excessive Mg from cells to ensure suitable cellular concentrations. This work confirms a conserved role of SGN3 in controlling nutrient homeostasis in B. rapa, and reveals mechanisms by which plants are able to deal with perturbed shoot element concentrations resulting from a "leaky" root endodermal barrier. Characterisation of variation in leaf Mg and Ca accumulation across a mutagenised population of B. rapa shows promise for using such populations in breeding programmes to increase edible concentrations of essential human and animal nutrients.
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The authors of the papers in this New Nutrition Science special issue of PHN give reasons for their commitment to a broad view of nutrition and food and nutrition policy
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lobally, more than 800 million people are undernourished while >2 billion people have one or more chronic micronutrient deficiencies (MNDs). More than 6% of global mortality and morbidity burdens are associated with undernourishment and MNDs. Here we show that, in 2011, 3.5 and 1.1 billion people were at risk of calcium (Ca) and zinc (Zn) deficiency respectively due to inadequate dietary supply. The global mean dietary supply of Ca and Zn in 2011 was 684 ± 211 and 16 ± 3 mg capita−1 d−1 (±SD) respectively. Between 1992 and 2011, global risk of deficiency of Ca and Zn decreased from 76 to 51%, and 22 to 16%, respectively. Approximately 90% of those at risk of Ca and Zn deficiency in 2011 were in Africa and Asia. To our knowledge, these are the first global estimates of dietary Ca deficiency risks based on food supply. We conclude that continuing to reduce Ca and Zn deficiency risks through dietary diversification and food and agricultural interventions including fortification, crop breeding and use of micronutrient fertilisers will remain a significant challenge.
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The adult human body contains approximately 24 g (1 mol) of magnesium--about half in bone and half in soft tissues. Only about 0.3% of the total body magnesium is present in serum, yet the majority of analytical data obtained is from this body fluid. Assessing the magnesium status of an individual is difficult, there being at present no simple, rapid, and accurate test to determine intracellular magnesium, but determination of total and free magnesium in tissues and physiological tests provide some information. Changes in magnesium status have been linked to cardiac arrhythmias, coronary heart disease, hypertension, and premenstrual syndrome. A better understanding of magnesium transport and of factors controlling magnesium metabolism is needed to elucidate the role of magnesium in disease processes.
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During a 20 day period of high fiber consumption in the form of bread made partly from wheaten wholemeal, two men developed negative balances of calcium, magnesium, zinc and phosphorus due to increased fecal excretion of each element. The fecal losses correlated closely with fecal dry matter and phosphorus. Fecal dry matter, in turn, was directly proportional to fecal fiber excretion. Balances of nitrogen remained positive. Mineral elements were well-utilized by the same subjects during a 20 day period of white bread consumption.
Article
The widespread assumption that the average daily intake of magnesium is sufficient to maintain equilibrium in the normal adult has been questioned. Analysis of published metabolic data indicates that the minimal daily requirement is not 220 to 300 mg. per day, as has been reiterated, or even 5 mg. per kg. per day as has also been suggested, but probably at least 6 mg. per kg. per day. The available clinical metabolic data provide evidence that at intakes below 6 mg. per kg. per day, negative magnesium balance is likely to develop, particularly in men. Women seem to retain more magnesium than men at low and marginal magnesium intakes. At intakes above 10 mg. per kg. per day, strong positive magnesium balances develop, which probably reflect repletion of suboptimal tissue stores. High protein, calcium and vitamin D intakes, and alcohol all function to impede retention or to increase the requirement of magnesium, particularly in those on low magnesium intakes. On magnesium intakes above 6 mg. per kg. per day, little interference with magnesium retention by calcium, protein or vitamin D has been reported. The diet in the Orient apparently provides 6 to 10 mg. per kg. per day. The Occidental diet, however, provides an average of 250 to 300 mg. of magnesium daily, or less than 5 mg. per kg. per day for most adults. Because the Western diet is often also rich in protein, calcium and vitamin D, and alcohol ingestion is common, it is suggested that the optimal daily intake of magnesium should be 7 to 10 mg. per kg. per day. The existence of subacute or chronic magnesium deficiency is difficult to diagnose. Because the tissues damaged by magnesium depletion are those of the cardiovascular, renal and the neuromuscular systems, early damage is not readily detectable. It is postulated that long-term suboptimal intakes of magnesium may participate in the pathogenesis of chronic diseases of these systems.