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The Role of Vitamins and Minerals in Energy Metabolism and Well-Being

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Physicians are frequently confronted with patients complaining of fatigue, tiredness and low energy levels. In the absence of underlying disease, these symptoms could be caused by a lack of vitamins and minerals. Certain risk groups like the elderly and pregnant women are well-recognized. Our aim was, therefore, to find out if other, less well-established groups might also be at risk. Thus, the objectives of this review are: to describe the inter-relationship between micronutrients, energy metabolism and well-being; identify risk groups for inadequate micronutrient intake; and explore the role of micronutrient supplementation in these groups. A review of the literature identified an important group at risk of inadequate micronutrient intake: young adults, often women, with a demanding lifestyle who are physically active and whose dietary behaviour is characterized by poor choices and/or regular dieting. Micronutrient supplementation can alleviate deficiencies, but supplements must be taken for an adequate period of time.
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Journal of International Medical
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DOI: 10.1177/147323000703500301
2007 35: 277Journal of International Medical Research
E Huskisson, S Maggini and M Ruf
The Role of Vitamins and Minerals in Energy Metabolism and Well-Being
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The Journal of International Medical Research
2
007; 35: 277 – 289
277
The Role of Vitamins and Minerals in
Energy Metabolism and Well-Being
E HUSKISSON
1
, S MAGGINI
2
AND M RUF
2
1
Consultant Physician, King Edward VII Hospital, London, UK;
2
Bayer Consumer Care AG,
Basel, Switzerland
Physicians are frequently confronted with
patients complaining of fatigue, tiredness
and low energy levels. In the absence of
underlying disease, these symptoms could
be caused by a lack of vitamins and
minerals. Certain risk groups like the
elderly and pregnant women are well-
recognized. Our aim was, therefore, to
find out if other, less well-established
groups might also be at risk. Thus, the
objectives of this review are: to describe the
inter-relationship between micronutrients,
energy metabolism and well-being; identify
risk groups for inadequate micronutrient
intake; and explore the role of micro-
nutrient supplementation in these groups.
A review of the literature identified an
important group at risk of inadequate
micronutrient intake: young adults, often
women, with a demanding lifestyle who
are physically active and whose dietary
behaviour is characterized by poor choices
and/or regular dieting. Micronutrient
supplementation can alleviate deficiencies,
but supplements must be taken for an
adequate period of time.
KEY WORDS: VITAMINS; MINERALS; MICRONUTRIENTS; MICRONUTRIENT SUPPLEMENTATION; ENERGY
MET
ABOLISM
; WELL-BEING
Introduction
Every doctor is familiar with the patient who
presents complaining of a lack of energy,
tiredness and exhaustion, and for whom
thorough examination and even routine
laboratory tests do not provide a satisfactory
explanation for their symptoms. Without
any underlying diseases, might these
symptoms be caused by a lack of vitamins
and minerals?
Research in the latter half of the 20th
centur
y has dramatically increased our
understanding of the biochemical processes
of cellular energy generation and
demonstrated the fundamental role of a
large number of vitamins and minerals as
coenzymes and cofactors in these processes.
This paper is based on the recognition that a
lack of micronutrients may impair cellular
energy production, resulting in symptoms of
tiredness and lack of energy
. In the first part
of the paper, we summarize the current
understanding of the role of micronutrients
in energy generation and discuss the
implications of micronutrient deficiency for
energy and well-being. In the second part of
the paper, we discuss the potential role of
micronutrient supplements in improving the
well-being of patients complaining of lack of
energy and whether doctors should
recommend such supplements.
This review focuses on ‘healthy’ adults
278
E Huskisson, S Maggini, M Ruf
V
itamins and minerals in fatigue
with active and demanding lives. It refers
only briefly to athletes and sports
performance, because comprehensive
r
eviews about these groups and their specific
needs can be found easily in the literature.
For the same reason, we will also exclude
very well-known risk groups, such as the
elderly and those with vitamin B
12
and iron
deficiency.
Energy metabolism in the
body
Energy to power the body’s metabolic
processes is derived from the food that we
eat. Various reactions in catabolic pathways
release this energy and store it in the high-
energy phosphate bonds of the body’s energy
storage molecule, adenosine triphosphate
(
ATP). The process by which energy is
transformed into ATP is known as cellular
respiration (Fig. 1). The main part of this
cellular respiration happens in the
mitochondria, often referred to as the power
plants of the cell. Glucose is the body’s
preferred source of energy for the production
of ATP but, if necessary, other carbohydrates,
fats and proteins can also be metabolized to
acetyl coenzyme A (CoA), enter the citric
acid (Krebs) cycle and be oxidized to carbon
dioxide and water.
FIGURE 1: A simplified representation of cellular respiration with its four main steps.
From each molecule of glucose, a total of up to 38 molecules of adenosine
triphosphate (ATP) are produced. NADH, nicotinamide adenine dinucleotide (reduced
form); FADH
2
, flavin adenine dinucleotide (reduced form)
GLYCOLYSIS
ATP
NADH +H
+
1
FORMATION
OF ACETYL
COENZYME A
2
ELECTRON
TRANSPORT
CHAIN
4
3
Acetyl
coenzyme A
KREBS
CYCLE
ATP
ATP
NADH +H
+
FADH
2
NADH +H
+
CO
2
CO
2
O
2
H
2
O
Pyruvic acid
Glucose
e
e
e
279
E Huskisson, S Maggini, M Ruf
V
itamins and minerals in fatigue
ROLES OF MICRONUTRIENTS IN
ENERGY METABOLISM
The transformation of dietary energy
s
ources, such as carbohydrates, fats and
proteins into cellular energy in the form of
ATP requires several micronutrients as
coenzymes and cofactors of enzymatic
reactions, as structural components of
enzymes and mitochondrial cytochromes,
and as active electron and proton carriers in
the ATP-generating respiratory chain:
1,2
(i) thiamine pyrophosphate (TPP; vitamin
B
1
), CoA (containing pantothenic acid),
flavin mononucleotide (FMN; derived from
vitamin B
2
), flavin adenine dinucleotide
(FAD; derived from vitamin B
2
) and
nicotinamide adenine dinucleotide (NAD;
derived from nicotinamide) are involved in
the Krebs cycle and complexes I and II of the
respiratory chain; (ii) biotin, CoA and FAD
are involved in haem biosynthesis, which is
an essential part of the cytochromes and
important for the latter part of the
mitochondrial respiratory chain; (iii)
succinyl-CoA can feed into either the
respiratory chain or the Krebs cycle
depending on the needs of the cell.
In addition, the respiratory chain in the
mitochondria also involves iron – sulphur
(Fe – S) centres containing either two or four
iron atoms that form an electron transfer
centre within a protein.
The role of vitamins in energy metabolism
continues to attract research interest.
Depeint
et al.
2
confirmed the essential role of
vitamins B
6
, B
12
and folate in maintaining
the mitochondrial one-carbon transfer cycles
by regulating mitochondrial enzymes. The
same authors also emphasized the essential
role of the B vitamin family in maintaining
mitochondrial energy metabolism and how
mitochondria in their role as the cellular
organelles responsible for energy
metabolism are compromised by a
deficiency of any B vitamin.
3
As with the B vitamins, the role of certain
minerals in energy metabolism is the subject
o
f increasing interest. For example, a recent
review noted the importance of adequate
amounts of magnesium, zinc and chromium
to ensure the capacity for increased energy
expenditure and work performance, and
that supplemental magnesium and zinc
apparently improve strength and muscle
metabolism.
4
A subsequent paper
investigated the effects of magnesium
depletion on physical performance and
found that it resulted in increased energy
needs and an adverse effect on
cardiovascular function during sub-
maximal work.
5
Most recently, Lukaski has
shown that low dietary zinc also impairs
cardiorespiratory function during exercise.
6
Table 1 summarizes the present state of
knowledge with regard to the role(s) of
individual micronutrients in energy
metabolism.
7 – 10
Inadequate micronutrient
intake
The serious consequences of profound
vitamin deficiency have been recognized for
more than a century. Mainly as a result of
better general nutrition and of micronutrient
supplementation in at-risk groups, the
deficiency diseases, such as rickets, pellagra,
scur
vy and beriberi, are now relatively
uncommon, at least in the developed world.
But, within the past two decades, a number
of investigators
11,12
have re-introduced the
concept of marginal micronutrient
deficiency
, first proposed by Pietrzik in
1985.
13
This showed that, long before the
clinical symptoms of deficiency appear
,
micronutrient deficiencies develop
progressively through several sub-clinical
stages (Table 2).
Marginal deficiencies may occur as a
280
E Huskisson, S Maggini, M Ruf
V
itamins and minerals in fatigue
TABLE 1:
Present state of knowledge with regard to the role(s) of individual micronutrients in
energy metabolism
7 – 10
Micronutrient Function in energy metabolism
Vitamins
Thiamine (B
1
) Essential cofactor in the conversion of carbohydrates to energy.
Needed for normal muscle function, including the heart muscle.
Involved in oxidative carboxylation reactions, which also require
manganese ions.
Riboflavin (B
2
) As a cofactor in the mitochondrial respiratory chain, helps in the release
of energy from foods.
Component of the main coenzymes FAD and FMN.
Nicotinic acid, As a cofactor in the mitochondrial respiratory chain, helps in the release
niacin (B
3
) of energy from foods.
Transformed into NAD and NADP, which play a key role in oxidation –
reduction reactions in all cells.
Pyridoxine (B
6
) Helps in the release of energy from foods.
Used as a cofactor by nearly 100 enzymatic reactions, mainly in protein
and amino acid metabolism.
Vitamin B
12
Essential for metabolism of fats and carbohydrates and the synthesis of
proteins.
Interacts with folic acid metabolism.
Biotin As a cofactor, involved in metabolism of fatty acids, amino acids and
utilization of B vitamins.
Pantothenic acid Plays an essential role in the Krebs cycle.
Component of coenzyme A.
Vitamin C Essential for synthesis of carnitine (transports long-chain fatty acids into
(ascorbic acid) mitochondria) and the catecholamines, adrenaline and noradrenaline.
Ascorbic acid facilitates transport and uptake of non-haem iron at the
mucosa, the reduction of folic acid intermediates, and the synthesis of
cortisol.
Potent antioxidant.
Folic acid Folates function as a family of cofactors that carry one-carbon (C1) units
required for the synthesis of thymidylate, purines and methionine, and
required for other methylation reactions.
Folate is essential for metabolic pathways involving cell growth,
replication, survival of cells in culture.
Around 30 – 50% of cellular folates are located in the mitochondria.
Minerals
Calcium Essential for the excitability of muscles and nerves.
Activates a series of reactions including fatty acid oxidation,
mitochondrial carrier for A
TP (with magnesium), glucose-stimulated
insulin release.
Phosphorus Structural component of nucleotide coenzymes; ATP contains phosphorus,
as does creatine phosphate, another high-energy compound.
A
TP is involved in energy transformation and molecular activation.
281
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V
itamins and minerals in fatigue
TABLE 1 (continued):
Present state of knowledge with regard to the role(s) of individual micronutrients in
energy metabolism
7 – 10
Micronutrient Function in energy metabolism
Magnesium Essential for the excitability of muscles and nerves.
Cofactor in over 300 enzyme reactions, particularly those involving
metabolism of food components.
Required by all enzymatic reactions involving the energy storage
molecule ATP.
Trace elements
Copper Essential cofactor of cytochrome C oxidase, a component of the
mitochondrial respiratory chain.
Involved in iron metabolism.
Chromium (III) Potentiates insulin action, thus promoting glucose uptake by the cells.
Individuals who exercise strenuously have been reported to have higher
urinary levels of chromium.
Iron Essential part of haemoglobin for oxygen transport, of myoglobin for
transporting and storing oxygen in the muscle and releasing it when
needed during muscle contraction.
Facilitates transfer of electrons in the respiratory chain and is thus
important in ATP synthesis.
Necessary for red blood cell formation and function.
Manganese Cofactor of several enzymes involved in metabolism of carbohydrates
and gluconeogenesis.
Zinc Essential part of more than 100 enzymes, some of which are involved in
energy metabolism.
FAD, flavin adenine dinucleotide; FMN, flavin mononucleotide; NAD, nicotinamide adenine dinucleotide;
NADP, nicotinamide adenine dinucleotide phosphate; ATP, adenosine triphosphate.
result of inadequate micronutrient intake,
caused by poor diet, malabsorption or
abnor
mal metabolism. Whether in the
developed or the less developed world, the
overwhelming majority of cases fall into
stages 1 – 3 (Table 2) and are further referred
to as an inadequate micronutrient status.
Ideally
, a sufficient and balanced diet
should cover the overall micronutrient
requirements. Unfortunately
, even in
developed countries, many sections of the
population do not receive the essential
vitamins and minerals needed from their
diet. Several groups in the population are at
increased risk for inadequate micronutrient
status, usually due to insufficient intake
caused by weight-reducing diets, insufficient
and/or imbalanced nutrition, eating
disorders, or demanding periods such as
extensive exercise or emotional and/or
physiological stress. Increased requirements
may also cause an inadequate vitamin and
mineral status; for example, as may occur in
pregnancy and lactation, during growth, in
the elderly, smokers and chronic alcohol
abusers, and in patients with certain
underlying diseases.
14 – 17
Even otherwise ‘healthy’ individuals can
282
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V
itamins and minerals in fatigue
be at risk due to lifestyle-related factors. The
‘lifestyle’ category typically includes young
to middle-aged adults with high
occupational pressure or the double burden
of family and work, for whom time is always
in short supply. In this group, the risk for an
inadequate micronutrient status is often the
result of lifestyle-associated behaviour, such
as rushed meals, unhealthy food choices,
chronic or periodical dieting, and stress-
related behaviour, such as smoking,
excessive alcohol and coffee consumption.
18
Even mild micronutrient deficiencies can
result in a lack of well-being and general
fatigue, reduced resistance to infections or
impaired mental processes (e.g. memor
y,
concentration, attention and mood).
8,9
Recent studies have indicated that an
optimal intake of certain vitamins is also
crucial for long-term health maintenance
and to help prevent diseases, such as
osteoporosis, coronary heart disease and
cancer
.
19,20
The risk of developing an inadequate
micronutrient status is more common in
industrialized populations than is generally
assumed. In the 1987 – 1988 Dutch National
Food Consumption Survey,
21
combinations
of low thiamine, riboflavin, vitamin B
6
and
vitamin C intakes were found among adults.
A double-blind study demonstrated that a
state of depletion of thiamine, riboflavin,
and vitamins B
6
and C can be induced
within 8 weeks by a diet composed of normal
food products.
22
Within 3 – 6 weeks,
deterioration of the vitamin status was
indicated by decreased vitamin
concentrations in the blood, decreased
erythrocyte enzyme activities, elevation of
stimulation tests of these enzymes and lower
vitamin excretion in the urine.
22
Although
no vitamin-specific clinical signs and
symptoms of deficiency were obser
ved, this
depletion study showed that the combined
marginally deficient status of thiamine,
riboflavin, vitamin B
6
and vitamin C
resulted in decreased physical perfor
mance.
Marginal vitamin B
6
intake is among the
nutritional risks prevalent in The
Netherlands.
23
Vitamin and mineral intake was recently
assessed in the UK in an extensive survey
carried out in adults aged 19 – 64 years
living in private households.
24
Data from
TABLE 2:
The sub-clinical stages of marginal micronutrient deficiency
13
Stage Aetiology Evidence
Stage 1 Depletion of vitamin stores (more Measurement of vitamin/mineral levels in
rapid for water-soluble than for the blood or tissues.
fat-soluble vitamins).
Stage 2 Non-specific biochemical adaptation. Decreased excretion of metabolites in the
urine.
Stage 3 Secretion of micronutrient-dependant First physical signs; lack of energy, malaise,
enzymes or hormones reduced. loss of appetite, insomnia.
Stage 4 Reversible impairment of metabolic Morphological, metabolic or functional
pathways and cellular function. disturbances.
More pronounced physiological changes.
Stage 5 Irreversible tissue damage. Clinical signs of micronutrient deficiency.
283
E Huskisson, S Maggini, M Ruf
V
itamins and minerals in fatigue
more than 2250 dietary interviews were
gathered, along with more than 1700 7-day
dietary records. In general, the intake data
f
or vitamins and minerals were satisfactory,
showing an average intake from food
sources and supplements combined that met
or exceeded the local recommended daily
allowance (RDA) for each individual
micronutrient.
24
However, when only dietary
intake was considered and when looking at
the stratified intake data, significant
proportions of the population were found to
have intakes below the RDA, as shown in
Table 3.
24
Data from the USA have shown that, even
in the general population, the prevalence of
low serum folate (18.4%) and of low red-
blood cell folate (45.8%) was quite high.
25
This, in addition to the well-recognized roles
of folate in human health, prompted the
start of the mandatory folic acid fortification
programme in 1998 in the USA.
25
Dutch
data also indicated that around 50% of a
representative Dutch population sample did
not meet current recommendations for folate
intake.
26
Recently, it was reported that folic
acid deficiency in adolescent teenage girls in
Turkey ranged between 14.7% and 20.1% in
rural and urban areas, respectively.
27
Another vitamin of concern is vitamin D;
inadequate vitamin D status is becoming
more common in developed countries.
Vitamin D inadequacy is found in
approximately 36% of otherwise healthy
a
dults overall, in up to 57% of patients seen
in general medicine in the USA and at even
higher percentages in Europe.
28
Dietary magnesium does not generally
meet recommended intakes for adults.
Results of a recent national survey in the
USA, for example, indicated that a
substantial proportion of women do not
consume the recommended daily intake of
magnesium; with the menopause this
problem increases among women over 50
years old.
5
The average magnesium intake
for women was found to be 228 mg/day
compared with the recommendation of 320
mg/day by the US Institute of Medicine.
5
This
average intake amount was derived from a
1-day diet recall and, thus, may be an
overestimate of actual magnesium intake.
Magnesium has also been proposed as a
limiting nutrient for exercise and
performance. Surveys of physically active
individuals indicate that magnesium intakes
among certain groups of athletes do not
meet recommendations for adults.
4
A few
reports have indicated that magnesium
supplements enhance strength and improve
exercise performance.
29
However, it is
unclear whether these effects are related to
T
ABLE 3:
The results of an extensive survey of the diets of adults aged 19 – 64 years in the UK
24
Proportion of adults with an intake below the RDA
Micronutrients
Men (%) Women (%)
Vitamin B
1
12 13
Vitamin B
2
20 28
V
itamin B
6
6
10
Folate 11 30
Magnesium 50 74
Zinc
43 45
RDA, recommended daily allowance.
284
E Huskisson, S Maggini, M Ruf
V
itamins and minerals in fatigue
remediation of an existing magnesium
inadequacy or a pharmacological effect.
5
In both Europe and the USA, iron
d
eficiency is considered to be one of the main
nutritional deficiency disorders, affecting
large proportions of the population,
particularly children, and menstruating and
pregnant women.
30 – 33
Low consumption of foods rich in
bioavailable zinc, such as meat, particularly
red meat, and a high consumption of foods
rich in inhibitors of zinc absorption, such as
phytate, certain dietary fibres and calcium,
impair the recommended zinc status.
Inadequate zinc intake, resulting in a
suboptimal zinc status, has been recognized
in many population groups, both in less
developed and in industrialized countries.
Although the cause of this may be
inadequate dietary intake of zinc, the most
likely reason is the consumption of inhibitors
of zinc absorption.
34
Women, dieters and the
elderly are particularly at risk of being low in
zinc.
35,36
Surveys of physically active subjects
also indicate that low dietary zinc is
common, especially among individuals who
participate in aerobic activities, such as
those recommended to promote health and
well-being.
6
With respect to minerals and trace
elements in general, it is well established
that rigorous exercise leads to greater losses,
particularly of magnesium, iron, zinc and
chromium in sweat and urine.
37 – 40
In conclusion, the risk of an inadequate
micronutrient intake may be provoked by
the following different conditions and
situations:
(i) Elevated needs due to the induced
synthesis of those enzymes important to
energy metabolism which, in turn, increases
the requirements for micronutrient
cofactors.
41
(ii) Increased loss of minerals, such as
magnesium and iron, due to sweating
during exercise and in the urine.
37 – 40
In
general, micronutrient deficiencies caused by
h
igh physical activity (e.g. among active
individuals and athletes) are well
documented: B vitamins, vitamin C, iron;
42
vitamin B
2
in young women athletes;
43,44
B
vitamins, vitamin C;
45
and vitamin B
6
following marathon running.
46
(iii) Increased need because of dieting
and/or a poor diet, especially in
combination with a demanding lifestyle.
This is especially true of women living an
active life who frequently reduce intake of
food to lose weight as well as making poor
dietary choices. Such women have a
particular risk for insufficient B vitamin
status. Lifestyle-induced micronutrient
deficiency results in reduced physical
performance, increased fatigue and
tiredness.
47,48
(iv) Groups such as pregnant women or
the elderly must be mentioned, although
they are not further considered in this review.
Consequences of inadequate
micronutrient intake for
physical well-being
Given the importance of micronutrients in
energy metabolism it is not surprising that
mitochondrial functions are compromised
by insufficient dietar
y intake of B vitamins
and/or increased B vitamin needs.
3
Unfortunately, clinical data on the
interactions between micronutrient
metabolism and physical perfor
mance are
limited. This is mainly because study designs
have not been sufficiently comprehensive to
allow reasonable conclusions to be drawn
due to the complexity of cellular respiration
and the body’s ability to utilize alternative
pathways of energy production in an
emergency. Nevertheless, it has been shown
285
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V
itamins and minerals in fatigue
that deficiencies in folate and vitamin B
12
reduce endurance work performance and
that an inadequate intake of minerals
i
mpairs performance.
29
Studies of the effects of restricted diets on
physical performance have not only
emerged from sports medicine, but also as a
‘women’s health issue’. Concerns about the
health effects of chronic dieting in order to
reduce body weight have been regularly
voiced in both the medical and the lay press.
In a comprehensive review of the health
consequences of dieting in active women, a
‘chronic dieter’ is defined as an individual
who ‘consistently and successfully restricts
energy intake to maintain an average or
below-average body weight’.
47
The author
notes that individuals with a poor energy
intake usually have poor micronutrient
intakes, especially of calcium, iron,
magnesium, zinc and B complex vitamins.
47
These micronutrients are particularly
important for active individuals since, ‘they
play an important role in energy production,
haemoglobin synthesis, maintenance of
bone health and strength and an adequate
immune function’.
47
Problems may arise for
the active female who chronically diets and
performance may suffer in athletes involved
in aesthetic or ‘lean-build’ sports, such as
dancers, long distance runners or gymnasts,
who are under pressure to maintain a lean
body shape for their sport.
47
For active
females, ‘poor physical performance can
have a devastating psychological effect,
especially if physical performance is tied to
job-related expectations’.
47
Support is given to these conclusions by a
Spanish study that investigated energy
intake as a deter
minant factor of vitamin
status in healthy young women.
45
In this
study, the vitamin status (B
1
, B
2
, B
6
, retinol,
β-carotene, C and E) of 56 healthy young
women was analysed and related to energy
intakes. A high percentage of these
apparently healthy young women had
deficient or marginally deficient blood levels
o
f most of the vitamins, with adequate or
optimal levels only shown for vitamins C, E
and retinol. The authors concluded that
young women, especially those consuming
low-energy diets, are vulnerable to
developing marginal vitamin deficiencies.
Taken together, there is good evidence that
dietary restriction does result in an
inadequate micronutrient status and that
this may, in turn, impair physical
performance.
45,47
If deficiency of micronutrients can impair
physical performance, conversely physical
activity may deplete micronutrient status. In
a metabolic study, young women were fed
various amounts of riboflavin (vitamin B
2
)
over a 10-week period and their riboflavin
status was monitored.
43
When 20 – 50
min/day of exercise for 6 days a week was
introduced, riboflavin levels declined but
were restored when dietary riboflavin levels
were concomitantly increased. A similar
study found that, in the weeks when subjects
exercised, riboflavin status declined
significantly compared with the weeks in
which no exercise was performed.
44
More recently, a double-blind,
randomized, crossover study investigated the
effects of zinc deficiency on physical
per
formance.
6
Fourteen young men were fed
a low-zinc diet for 9 weeks and, following a
6-week washout period, they were then fed a
zinc-supplemented diet for a further 9 weeks.
Blood and faecal determinations of zinc
status and balance, and physiological
testing were performed at specific times
during each dietar
y period. The authors
concluded that low dietary zinc was
associated with impaired cardiorespiratory
function and impaired metabolic responses
during exercise. In establishing the 1998
286
E Huskisson, S Maggini, M Ruf
V
itamins and minerals in fatigue
dietary reference intake (DRI) for riboflavin,
the US Institute of Medicine considered data
from a number of metabolic studies and
c
oncluded that requirements might be
higher in active individuals, but the amount
of existing data was not sufficient to
quantify the requirement.
8
A number of studies have indicated that
vitamin B
6
is lost as a result of exercise,
although the magnitude of the loss is small.
Vitamin B
6
is required to maintain plasma
concentrations of pyridoxal 5’-phosphate
(PLP). Blood studies show that PLP levels rise
rapidly during exercise, indicating
consumption of vitamin B
6
.
48
In subjects
with an adequate B
6
intake, the levels fall
back to baseline within 30 – 60 min after
exercise.
48
As an example, it was calculated
that marathon runners lose about 1 mg
vitamin B
6
during a marathon, equivalent to
the DRI for an adult.
46
In a review of the effect of physical
activity on thiamine, riboflavin and vitamin
B
6
requirements
48
it was concluded that,
because exercise stresses metabolic pathways
that depend on thiamine, riboflavin and
vitamin B
6
, the requirements for these
vitamins may be increased in active
individuals. Since exercise seems to decrease
nutrient status even further in those with
pre-existing marginal vitamin intakes or
body stores, individuals ‘who restrict their
energy intake or make poor dietar
y choices
are at greater risk for poor thiamine,
riboflavin and vitamin B
6
status’.
48
In 2001 Speich et al.
49
published a review
of 24 studies carried out between 1994 and
2000 into the significance of levels of 16
minerals and trace elements for physical
per
for
mance. They concluded that, although
many of these minerals are involved in
aspects of energy metabolism, for most their
precise physiological role is still unclear. This
uncertainty underlines the need for further
research. A better understanding about
micronutrients and energy metabolism is
even more urgent because, besides the
i
mpact on physical well-being, currently the
long-term health consequences for humans
with marginal B vitamin deficiencies are not
known.
3
Micronutrient
supplementation
It is a well-known fact that, often
encouraged by their coaches, sports people
and athletes are major consumers of
multivitamins/mineral supplements. As an
example, Armstrong and Maresh
42
cite
studies from Australia showing that 30% –
100% of athletes in different sports have
taken supplements. With regard to the effects
of micronutrient supplementation on
physical performance, the literature
generally indicates that a positive effect on
physical performance is only detectable
when the dietary intake of these nutrients is
not adequate. This is supported by the most
recent review of this topic, in which the
author concluded that the use of vitamin
and mineral supplements did not improve
measures of performance in people
consuming adequate diets.
29
However,
‘young girls and individuals participating in
activities with weight classifications or
aesthetic components are prone to nutrient
deficiencies because they restrict food intake
and specific micronutrient-rich foods’.
29
Do the findings in athletes also apply to
‘normal’ people with only moderate physical
activity? Young women at risk of
micronutrient deficiency because of chronic
dieting have been identified
47
and, in a
subsequent paper
, it was shown that the risk
of deficiency was greatest in physically active
women with pre-existing marginal vitamin
status.
48
Indeed, both Manore
48
and
Lukaski
29
identified the same high risk
287
E Huskisson, S Maggini, M Ruf
V
itamins and minerals in fatigue
group, but from different perspectives:
Lukaski studied athletes and identified an ‘at
risk’ subgroup of young women who
r
estricted their diet;
29
w
hile Manore studied
chronic dieters and identified an ‘at risk’
subgroup who were physically active.
48
Both
authors concurred that multivitamin/
mineral supplementation may be beneficial
for such women.
Finally, a generally well-recognized group
for inadequate micronutrient intake is the
elderly. Diet, micronutrient status and the
benefits of supplementation have been
much studied in the elderly, however most
studies have concentrated on the effects of
deficiency on susceptibility to infection and,
more recently, cognitive function.
18
However,
lack of energy, tiredness, weakness and,
paradoxically, loss of appetite are frequent
complaints of older people. A recent study
confirmed earlier pan-European findings
that between 39% and 78% of elderly
subjects had dietary intakes of vitamin A,
calcium and iron below the lowest European
RDA;
50
the relationship between
micronutrient insufficiency and energy in
this group warrants further study.
As to how long to continue supple-
mentation, the evidence suggests that an
inadequate micronutrient status may take
several weeks to develop and, once it occurs,
it may take an equally long time to replenish
body stores. Although data are limited, an
experimental study showed that it took
around 6 weeks for daily supplementation of
vitamin B
6
to restore optimum blood levels.
51
Based on this and clinical data with
multivitamin products,
52,53
a treatment period
of at least 40 days is usually recommended.
Lichtenstein and Russell
54
recently
concluded that there are strong reasons to
make recommendations for the use of
dietary supplements by certain segments of
the population. ‘Supplements are relatively
inexpensive and can be reliably used to
administer nutrients in precise doses. If used
consistently, supplements can ensure
a
dequate intakes of specific nutrients in
targeted groups that have increased needs
for those nutrients because of physiologic
limitations or changes’.
54
Conclusion
An overwhelming body of physiological
evidence confirms the fundamental role of
vitamins and minerals in energy
metabolism. In particular, the B complex
vitamins are essential for mitochondrial
function and a lack of just one of these
vitamins may compromise an entire
sequence of biochemical reactions necessary
for transforming food into physiological
energy. It is also clear that several minerals
and trace elements are essential for energy
generation, although more research is
needed to elucidate their precise role.
Inadequate intake of micronutrients, or
increased needs, impairs health and
increases susceptibility to infection, but may
also result in tiredness, lack of energy and
poor concentration. Besides generally
accepted risk groups like the elderly, an
important group who are at risk of an
inadequate micronutrient intake – especially
of the B vitamins – are young to middle-aged
adults. These are often women with a
demanding lifestyle who are physically
active and whose dietary behaviour might
be characterized by poor choices and/or
regular attempts to lose weight.
Given the importance of micronutrients
for energy metabolism and the risk for an
inadequate micronutrient status in otherwise
healthy individuals, multivitamin – mineral
supplementation is recommended for
patients complaining of chronic lack of
energy and in whom underlying disease has
been excluded. Where such supplements are
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Address for correspondence
Dr S Maggini
Bayer Consumer Care AG, 4052 Basel, Switzerland.
E-mail: silvia.maggini.sm@bayer
.ch
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V
itamins and minerals in fatigue
... D 'après Brouns et al. (2012) et Huskisson et al. (2007). 154 ...
... L'aleurone concentre la majeure partie des minéraux et vitamines du grain de blé (Brouns et al., 2012). Ces vitamines jouent un rôle dans le métabolisme énergétique en étant des cofacteurs dans différentes réactions impliquées dans la production d'énergie, tels que la chaine mitochondriale ou le transport et le stockage de l'ATP (tableau 15; Huskisson et al., 2007, Brouns et al., 2012. Enfin, bien qu'à l'heure actuelle, nous n'ayons pas encore les résultats sur la composition de la flore microbienne des porcs, une action de l'aleurone sur le microbiote est envisageable, avec de possibles changements en termes de quantité ou de composition de la flore microbienne Chez les porcs en finition, une tendance pour une diminution de la production de méthane en proportion de l'énergie digestible ingérée a été observé (P=0,10). ...
... Tableau 15 Rôles des micronutriments de l'aleurone de blé dans le métabolisme énergétique. D'après Brouns et al., 2012et Huskisson et al., 2007. Participe à la libération d'énergie des composants alimentaires Utilisée en facteur dans des réactions enzymatiques dans les métabolismes des protéines et des acides aminés Minéraux Magnésium 530 Cofacteurs dans les réactions du métabolisme des composants alimentaires Nécessaire pour les réaction enzymatique impliqué dans le stockage de l'ATP Calcium 55 Active des réactions telles que l'oxydation des acides gras, la sécrétion d'insuline glucose-dépendante, le transport d'ATP Fer 27 Composant principale de l'hémoglobine qui participe au transport de l'oxygène Facilite le transport des électrons dans la chaine mitochondriale pour la synthèse d'ATP Zinc 8,3 Composant de plus de 100 enzymes, dont certaines sont impliquées dans le métabolisme énergétique ...
Thesis
En élevage porcin, le niveau alimentaire affecte les résultats économiques et les rejets environnementaux. La consommation journalière se traduit par une dynamique d’ingestion caractérisé par le nombre et la taille des repas. Afin de réduire l’ingestion volontaire en fin d’engraissement, il est nécessaire de comprendre les mécanismes de régulation du comportement alimentaire pour mettre en place des solutions améliorant la satiété. L’objectif de cette thèse est d’étudier les voies de régulation du comportement alimentaire et leurs interactions. Ce travail a consisté à étudier le comportement alimentaire au cours de deux essais effectués sur de porcs en croissance et en finition. Différentes voies de régulations ont été étudiées à différents pas de temps allant de l’échelle d’un repas à la journée. Des fibres alimentaires ont été introduites dans l’aliment et des animaux avec des comportements alimentaires extrêmes ont été sélectionnés. La thèse a permis de tester l’aleurone de blé, en tant que candidat satiétogène. Chez des mâles castrés en croissance, la supplémentation en aleurone de blé a diminué la consommation journalière en diminuant le nombre de repas par jour. Chez les porcs en finition, l’effet de l’aleurone a réduit le nombre de repas chez les femelles mais n’a eu aucun effet sur le comportement alimentaire des mâles castrés. Différents profils d’animaux ont pu être décrits, associant des différences de comportements alimentaires avec des différences de métabolismes énergétiques. L’ingestion volontaire est donc le résultat complexe de plusieurs voies de régulation. La diminution de l’ingestion volontaire n’est possible qu’en travaillant sur les différentes voies.
... The mechanism of RF electro-reduction is wellknown and usually proposed as a two-electron reduction process in which RF is reduced to the dihydroriboflavin (Scheme 1) [20][21][22]. RF also supplements the energy demands of our body by participating in the conversion of vital nutrients (fats, proteins and carbohydrates) into ATP [23]. ...
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Nickel acetate tetrahydrate (NAT) sample series were used to modify screen-printed carbon electrodes (SPCE). The samples were hybrid Ni/NiO nanocomposites, where the NiO phase increased with an applied treatment temperature. Results of electrochemical measurements pointed that the Ni/NiO550/SPCE-modified electrode had the best analytical performance toward the detection of riboflavin (RF). The Ni/NiO550/SPCE-based sensor showed linear response with RF in the concentration range of 0.5-75 μM and 0.15 μM LOD in BRBS. Sensor offered fast response time, good repeatability, and selectivity with an RSD of 1.4%. Our results show that the Ni:NiO nanocomposite ratio strongly influenced the electroanalytical performance of SPCE.
... Though reducing energy intake was a necessary response to lockdown, swimmers should be aware that energy reductions also increase the risks of developing micronutrient deficiencies [22,23]. This risk may be greater in athletic adolescents, who may require greater calcium (e.g., 1100-1500 mg [46,47] and iron intakes (e.g., 22 mg�day -1 for females [48]) than the general population to offset deficiency symptoms, such as illness, muscle fatigue, cognitive impairments, and osteoporosis [49,50]. The current study adds to this concern by identifying reduced intakes for nine different vitamins and minerals during lockdown, including iron, calcium, potassium, and selenium, which all fell below the British reference nutrient intake (RNI) for adolescents (aged 15-18 years [31]). ...
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Strict lockdown measures were introduced in response to the COVID-19 pandemic, which caused mass disruption to adolescent swimmers’ daily routines. To measure how lockdown impacted nutritional practices in this cohort, three-day photograph food diaries were analysed at three time points: before (January), during (April), and after (September) the first UK lockdown. Thirteen swimmers (aged 15 ± 1 years) from a high-performance swimming club submitted satisfactory food diaries at all time points. During lockdown, lower amounts of energy (45.3 ± 9.8 vs. 31.1 ± 7.7 kcal∙kg BM∙day ⁻¹ , p <0.001), carbohydrate (5.4 ± 1.2 vs. 3.5 ± 1.1 g∙kg BM∙day ⁻¹ , p <0.001), protein (2.3 ± 0.4 vs. 1.7 ± 0.4 g∙kg BM∙day ⁻¹ , p = 0.002), and fat (1.6 ± 0.4 vs. 1.1 ± 0.3 g∙kg BM∙day ⁻¹ , p = 0.011) were reported. After lockdown, no nutritional differences were found in comparison compared to before lockdown (energy: 44.0 ± 12.1 kcal∙kg BM∙day ⁻¹ ; carbohydrate: 5.4 ± 1.4 g∙kg BM∙day ⁻¹ ; protein: 2.1 ± 0.6 g∙kg BM∙day ⁻¹ ; fat: 1.5 ± 0.6 g ∙kg BM∙day ⁻¹ , all p >0.05), despite fewer training hours being completed (15.0 ± 1.4 vs. 19.1 ± 2.2 h∙week ⁻¹ , p <0.001). These findings highlight the ability of adolescent swimmers to alter their nutrition based on their changing training circumstances when receiving sport nutrition support. However, some individuals displayed signs of suboptimal nutrition during lockdown that were not corrected once training resumed. This warrants future research to develop interactive education workshops that maintain focus and motivation towards optimal nutrition practices in isolated periods away from training.
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Micronutrients, namely, vitamins and minerals, are necessary for the proper functioning of the human body, and their deficiencies can have dramatic short‐ and long‐term health consequences. Among the underlying causes, certainly a reduced dietary intake and/or poor absorption in the gastrointestinal tract play a key role in decreasing their bioavailability. Recent evidence from clinical and in vivo studies suggests an increasingly important contribution from the gut microbiome. Commensal microorganisms can in fact regulate the levels of micronutrients, both by intervening in the biosynthetic processes and by modulating their absorption. This short narrative review addresses the pivotal role of the gut microbiome in influencing the bioavailability of vitamins (such as A, B, C, D, E, and K) and minerals (calcium, iron, zinc, magnesium, and phosphorous), as well as the impact of these micronutrients on microbiome composition and functionality. Personalized microbiome‐based intervention strategies could therefore constitute an innovative tool to counteract micronutrient deficiencies by modulating the gut microbiome toward an eubiotic configuration capable of satisfying the needs of our organism, while promoting general health.
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Changes in nutritional status during supplementation with a high-potency multivitamin-mineral supplement were examined in 22 physically active men randomly assigned to take a supplement (n = 11) or placebo (n = 11) for approximately 12 wk. Four-day dietary intakes, blood concentrations, and urinary excretions of selected vitamins and minerals were measured before, during (approximately 6 and 12 wk), and after supplementation. No changes were observed in blood concentrations of vitamins A and C and measures of zinc, magnesium, and calcium status; the supplement provided less than 300% of the recommended dietary allowance (RDA) of these nutrients. In contrast, blood concentrations of thiamin, riboflavin, vitamins B-6 and B-12, pantothenate, and biotin increased significantly (P less than 0.05) by 6 wk to values that were maintained until the end of the supplementation. These vitamins were provided in amounts that ranged from 396% (biotin) to 6250% (vitamin B-6) of the RDA. Urinary excretions of these vitamins also increased during supplementation and both blood and urine values returned to presupplementation concentrations at approximately 13.5 wk postsupplementation.
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The major biochemical function of zinc is as a constituent of metalloenzymes. The first described was carbonic anhydrase in 1940, and since then more than 200 different zinc enzymes have been identified in plant and animal tissue. Alcohol dehydrogenase, superoxide dismutase, DNA-polymerase, RNA-polymerase, alkaline phosphatase and carboxypeptidase are all zinc-metalloenzymes and examples can be found in each of the six major categories of enzymes. This means that zinc is involved in more or less every biochemical process in the body. In some of these enzymes zinc is present at the active site e.g., acting as an electron acceptor, in others and in non-enzyme proteins the function of zinc is structural as S—S bridges or cross-links between thiolates and imidazoles.
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Objective. —To determine the prevalence of iron deficiency and iron deficiency anemia in the US population.Design. —Nationally representative cross-sectional health examination survey that included venous blood measurements of iron status.Main Outcome Measures. —lron deficiency, defined as having an abnormal value for at least 2 of 3 laboratory tests of iron status (erythrocyte protoporphyrin, transferrin saturation, or serum ferritin); and iron deficiency anemia, defined as iron deficiency plus low hemoglobin.Participants. —A total of 24 894 persons aged 1 year and older examined in the third National Health and Nutrition Examination Survey (1988-1994).Results. —Nine percent of toddlers aged 1 to 2 years and 9% to 11% of adolescent girls and women of childbearing age were iron deficient; of these, iron deficiency anemia was found in 3% and 2% to 5%, respectively. These prevalences correspond to approximately 700000 toddlers and 7.8 million women with iron deficiency; of these, approximately 240 000 toddlers and 3.3 million women have iron deficiency anemia. Iron deficiency occurred in no more than 7% of older children or those older than 50 years, and in no more than 1% of teenage boys and young men. Among women of childbearing age, iron deficiency was more likely in those who are minority, low income, and multiparous.Conclusion. —lron deficiency and iron deficiency anemia are still relatively common in toddlers, adolescent girls, and women of childbearing age.
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Nine male runners (23-46 yr) ran 6 mi near their maximal pace. Blood and urine samples were obtained prior to, immediately after, and 2 h following the run; 24-h urine collections were also taken on the run and nonrun days. Serum chromium increased significantly (P < 0.05) from 0.12 ± 0.02 (mean ± SE) to 0.17 ± 0.03 ng/mL immediately following running and remained elevated, 0.19 ± 0.03 ng/mL, after 2 h. Urinary chromium concentration was elevated several-fold 2 h following running and daily urinary chromium losses were about twofold higher on the day of the run compared to a rest day. Serum zinc was not significantly different from prerun values immediately following running, 81 ± 4 and 85 ± 4 pμg/dL, respectively, but then decreased significantly to 75 ± 4 2 h after exercise. Urinary zinc concentration was elevated more than twofold 2 h after running and total urinary losses on the day of the run were more than 1.5-fold higher than those on the nonrun day. Serum copper was not altered by exercise. Serum high density lipoprotein (HDL) cholesterol, but not total cholesterol increased significantly following running. HDL cholesterol values were similar to prerun values within 2 h of running. Serum triglycerides, phosphate, creatinine, bilirubin, uric acid, and alkaline phosphatase were also elevated immediately following running, whereas albumin, total protein, and blood urea nitrogen remained constant. These data demonstrate that accompanying the transitory changes in selected clinical indices caused by strenuous running there are alterations in chromium and zinc concentrations in serum and urine and increased specific urinary losses of these essential nutrients.
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Evidence suggests that there is ever increasing pressure on American women to be thin. This pressure drives women to want to be thinner than what might be realistically achieved or required for good health. Our goal as nutrition and health professionals is to help women achieve and maintain a healthy body weight throughout the life-cycle. This includes helping young females accept their body size and shape as well and placing more emphasis on health and fitness than on weight in this population. This process begins with the identification of what constitutes a healthy body weight for a particular individual based on genetic, physiological, social, and psychological factors. In addition, it should be a weight that can be realistically maintained while keeping risk factors for chronic disease low. Table 1 outlines some strategies for helping individuals to identify and maintain a healthy body weight.Since the military demands that soldiers meet body weight standards, it is imperative that they also provide accurate and motivating diet and exercise education programs to help soldiers achieve these standards. For the female soldier the pressure to maintain a thin body is twofold: both from society and the military. Research shows that when pressures to achieve a weight goal are high, women will attempt any weight loss method to achieve success, regardless of health consequences. Thus, any successful weight-loss or weight-maintenance program needs to address lifestyle changes that can help soldiers achieve and maintain healthy weight and fitness goals throughout their military careers.
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The effects of exercise training on riboflavin requirements and of riboflavin intake on endurance were examined in 14 women, 50-67 y of age, who participated in a 10-wk, two-period crossover exercise study at two riboflavin intakes, 0.15 micrograms/kJ (0.6 micrograms/kcal) and 0.22 micrograms/kJ (0.9 micrograms/kcal). Subjects exercised 20-25 min/d, 6 d/wk, for 4-wk periods on a cycle ergometer at 75-85% of their maximal heart rate. Riboflavin status was assessed by measuring the erythrocyte glutathione reductase activity coefficient (EGRAC) and urinary riboflavin excretion. Physical performance was evaluated by using a walking treadmill test to determine maximal oxygen capacity (VO2max) and anaerobic threshold by gas exchange (ATGE). Exercise significantly affected riboflavin status as EGRAC increased (P less than 0.001) and riboflavin excretion decreased (P less than 0.01) in both groups. VO2max increased significantly with exercise (P less than 0.01). However, changes in VO2max (L/min) and ATGE with exercise training were not different in the two groups. Riboflavin requirements of older women increased with exercise training, but increased riboflavin intake did not enhance improvements in endurance.
In comparison with drugs, the postabsorptive curves of nutrients must be interpreted differently concerning their pharmacokinetic behavior: (1) Most nutrients do not behave as "nonreactives" in a strict sense. (2) For nutrients, the calculation of the retained quantity is important and not the calculation of the attainable concentration as in the case with drugs. These principles are shown for a lipid and a water soluble substance by calculated and observed cumulation curves: (1) The carotenoid canthaxanthin shows limited absorption. The primary invasion occurs via lymphatics as chylomicra. After absorption, the carotenoid shifts in part into other lipoprotein fractions with very low elimination constants, thus forming typical cumulation curves of very high plasma concentrations. (2) Vitamin B6, in contrast, is absorbed in an unlimited way up to very high doses. Nevertheless, rapid excretion prevents longlasting cumulation effects. However, chronical ingestion causes higher concentrations of binding proteins in different tissues. In this way, another type of long-lasting cumulation effect is induced.