by Aftab J. Ahmed, Ph.D.
Minerals:
Navigating the Alphabet Soup
With the progressive upsurge in
the use of nutraceuticals and nutritional supplements,
it is sometimes forgotten that vitamins
and minerals were the first on the scene to compensate
dietary deficiencies. That is one of the
reasons for the continued popularity of the socalled
“multivitamins” to help alleviate nutritional
inadequacies of vitamins and minerals.
Not much effort is made, however, to distinguish
between vitamins and minerals. Furthermore,
minerals are usually given a short shrift, despite
their centrality to a balanced diet
unless, of course, a mineral is directly
linked to a common disease. As an
example, selenium came to the forefront
recently because it is indispensable
in prostate health. Selenium,
incidentally, is woefully low in the
typical American diet due to topsoil
erosion.
Ordinarily a balanced diet should
provide the entire complement of
requisite amounts of nutrients.
Nutriment, the part of food that
nourishes the body, consists of macroand
micronutrients. Macronutrients
are composed of protein, carbohydrate
and fat. Micronutrients include
vitamins and minerals, naturally
occurring chemical elements, which
are essential in maintenance of health.
Micronutrients are consumed in relatively small
amounts (usually less than one gram total per
day). They are absorbed unchanged and are
involved in a myriad of metabolic activities.
Minerals are classified as either major or trace
minerals, depending upon their relative abundance
in the human body. Among the major
minerals are calcium (Ca), phosphorus (P), potassium
(P), sodium (Na) and magnesium (Mg).
Trace minerals, on the other hand, include iron
(Fe), manganese (Mn), iodine (I), zinc (Zn),
chromium (Cr) and among others, selenium (Se).
Whereas major minerals comprise roughly 0.005
percent of the body weight, trace elements are an
order of magnitude less abundant, to the tune of
approximately 0.0005 percent.
The importance of minerals, however, is
independent of their relative amounts in the
body. Only the concentration of a few major
minerals, involved in the maintenance of acidbase
balance of the body fluids, changes somewhat.
That deficit is promptly replenished,
however, by mobilization of those minerals,
such as calcium, from the bone.1 By and large,
however, availability of minerals within the
range of their natural abundance is absolutely
essential in human health and disease. Thus,
despite its small amounts in the body, iron deficiency
causes anemia, which progresses to weakness
and wasting.
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| a. Linear Response |
b. Psychological Effect |
c. Pharmacological Effect |
| Fig. 1: Effect of a Nutritive/Therapeutic Agent. Physiological effect is elicited by a dose equivalent to the amount of a nutrient normally found ing the body, whereas pharmalogical response results at a much higher dose, at which unexpected, drug-like effects are often observed. |
Iodine is also present in the body in infinitesimal
quantities but even so its inadequacy skews
the basal metabolic rate (BMR). Iodine is a part of
thyroxin, a hormone secreted by the thyroid
gland, which is responsible for BMR, that is, the
rate at which oxygen is consumed by the cell and
the energy produced. More importantly, to offset
chronic deficiency, the thyroid enlarges to
trap as much iodine as possible. If the gland is
enlarged sufficiently to be visible, it is referred to
as goiter, a condition that afflicts hundreds of
millions of people worldwide.
These examples are but two of many that
illustrate how critical even minuscule amounts
of minerals are in the function of internal
organs.
Combined with the recent findings that
minerals are being depleted from the
soil and elucidation of the central role
minerals play in cellular function, great emphasis
has been placed over the years to supplement
diet with minerals. It is for good reason then that
the dairy industry has begun to package the benefits
of milk more as a source of calcium and beef is touted as a rich repository of vitamins and
minerals. Inasmuch as vitamin and mineral supplementation
is necessary, in general, there is
also a tendency to lose sight of the fact that overdosing
with otherwise beneficial substances can
be detrimental to health. For instance, chronic
iron overload overwhelms the intestinal cells
that otherwise block excess iron absorption and
it begins to accumulate in various tissues (hemosiderosis).
If iron deposition is accompanied
with tissue damage, notably to the liver,
hemochromatosis results.2 By the same token,
ill-considered copper (Cu) supplementation
could potentially sequester zinc (Zn), and vice
versa, both of which can be detrimental to
health and well-being.
In part at least, consumption of excessive
amounts of minerals—or for that matter,
any nutritional supplement—may well seem
justified based on the results of published studies.
Within the physiological context, however,
it should be clearly recognized that the amounts
used in a study could not always necessarily be
extrapolated to the human condition.
Accordingly, any supplementation must be
calibrated to individual needs after careful consideration
of a variety of factors.
To derive health benefits from ingestion of
large amounts of nutrients—whether minerals,
vitamins, or herbals—stems from a misconception
that a linear correlation prevails between
the dose of a supplement and its putative effect.
In other words, the assumption is that escalating
doses of a beneficial nutrient would amplify its
effects (Fig. 1a). That such is not the case is
poignantly demonstrated by the example of
insulin. At a lower dose, insulin lowers blood
glucose levels by facilitating its transport into the
cell. At much higher concentration, however,
insulin turns coat and actually increases blood
glucose levels. Thus, at higher dosages insulin
exerts a pharmacological rather than a physiological
effect. The distinction implicit in this
line of reasoning is that whereas a “normal”
dose, however arrived at, has physiological
effects (Fig. 1b), massive doses are potentially
pharmacological (Fig. 1c) and hence, may not be
as innocuous as is generally thought.
Pharmacological doses are almost always associated
with side effects, as with pharmaceuticals.
As such, both mineral deficiency and excess can
foment a perfect storm in the body. For example,
excess accumulation of fluoride may yield
fluorosis and to cite another example, large Cu
deposits in the liver and brain can induce
Wilson’s disease.
How does mineral toxicity come about,
though? Minerals, because of their relative
scarcity, are literally the body’s gold
and therefore, should be exquisitely regulated.
This is exactly what the body is designed to do.
Generally, in order for minerals to be delivered
to various tissues and organs, they are bound to
specific carriers. These carriers serve as de facto
gatekeepers for mineral absorption (Fig. 2). Since
these gatekeepers are the limiting factor in determining
how much supplemental mineral will be
absorbed, it has been argued that intake of
unbound minerals is less efficient in meeting the
metabolic demands. Therefore, more natural
vehicles, such as milk for Ca and yogurt for
Lactobacilli, are better suited to satisfy physiological
requirements for various nutrients.
That has also been in part the rationale in
identification and isolation of, for want of a better
term, minerals integral to an herb or a plant.
The main advantage of integral minerals is their
potential for enhanced bioavailability and
greater distribution throughout the body as
opposed to “naked” minerals.3 It is said, with
some justification, that
one serving each day of a
specific mineral-rich
food over the long term
could easily supply the
necessary amount, lending
credence to the old
saying that “an apple a
day” could well stave off
disease. The most pertinent
example of this
axiom is potassium (K) in
bananas. Potassium deficiency
is implicated in
the onset of heart disease,
and considerably increases
the risk of stroke. One
standard-sized banana
contains close to 400 mg
of K, which is sufficient to modulate blood pressure.
Intake of 400 mg K in its chemical form, on
the other hand, would have to be discouraged.
Another example of an integral mineral is Cr
complexed with glucose transport factor (GTF), a
small organic compound that functions as the
wayfarer, in the management of blood sugar levels.4 Since the amounts of Cr needed to regulate
carbohydrate metabolism are minuscule, dispensation
of unbound Cr has the distinct potential
of toxicity. Therefore, GTF-complexed Cr has
a far higher probability of not only being beneficial
but also of ensuring clearance of any excessive
amounts to obviate Cr load. Given that, the
keenness to develop alternatives that maximize
mineral delivery to various tissues and organs is
right on target. Quite likely future research
efforts will be geared toward identification of
diverse natural sources of minerals associated
with organic compounds.
A prototypical nutrient suchlike is inulin, a
fructooligosaccharide, isolated from the root of
Jerusalem artichoke. Primarily, inulin functions as
a prebiotic and promotes exclusively the growth
of colonic beneficial flora and helps restore floral
balance. Interestingly, inulin also promotes the
uptake of supplemental minerals, notably that of
calcium.5 The most plausible explanation for
increased absorption of a mineral taken in tandem
with inulin is that by-products of bacterial
fermentation must be resorbed in the blood-stream. As these metabolites are resorbed, they
exert a drag effect on nutrients, either derived
from foodstuffs or supplemental, for their
absorption in the bloodstream. Another likely
mechanism for increased absorption of minerals
is the fact that inulin is isolated along with integral
minerals. Among the most important integral
minerals in inulin are K, P, Ca, Na, Mg, Fe and
sulfur (S) (Table 1).With inulin consumption as a
prebiotic substrate in the colon, it gradually
releases integral minerals, which upon resorption
stimulate the uptake dietary/supplemental
minerals as well.
Inulin derived from the Jerusalem artichoke
root may well be the singular example to
date of numerous minerals integral to an
active principle. Efforts have been undertaken
to package minerals in herbal extracts in a quasiorganic
milieu to make them both more
bioavailable and, concomitantly, to minimize
the risk of metal toxicity. Mineral supplementation
comes with the inherent uncertainty that it
is virtually impossible to determine how much
minerals are being taken up through foodstuffs.
Therefore, any approach to formulate a mineral
complex is straddled with the challenge not
only to calibrate minerals relative to each other
in a given formulation but also with other principles
that may be added, such as vitamins,
herbals and/or chemicals. Absent that, despite a
well-rounded alphabet soup of minerals, there
may well be a dearth amidst the proverbial
abundance.
The original intent and thrust of nutritional
intervention was to supplement the diet with
agents necessary for optimal health. Over time,
nutritional supplementation has apparently
made a drastic transition. It is now seen as a
means to prevent, if not outright treat, diseases.
That is a secret hiding in plain sight. That
expectation is unlikely to be realized unless, of
course, considerably greater understanding of
the interactions of various “health foods” is
garnered with specific emphasis on the conditions
that they are supposed to help ameliorate.
Irrespective of that, supplementation with
vitamins and minerals afford one reasonable
approach to help support the scaffold for
optimal health in an increasingly aging
populace.
Aftab J. Ahmed, Ph.D. is vice president, director
of research and development and business
development at Marlyn Nutraceuticals, Inc.
E-mail:
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Selected references
- Ahmed, A. “Osteoporosis: Diet, Acidity and Calcium,” totalhealth (2002). Vol. 24(2), p. 52.
- Ahluwalia, N. “Diagnostic Utility of Serum Transferrin Receptor Measurements in Assessing Iron Status,” Nutr. Rev. (1998). Vol. 56, p. 133.
- Ahmed, A. “Nutraceuticals: Absorption and Bioavailability,” totalhealth (2002). Vol. 24(1), p. 70.
- Anderson, R. “Effects of Chromium on Body Composition and Weight Loss,” Nutr. Rev. (1998). Vol. 56, p. 266.
- Ahmed, A. “IBS: The Unsettled Gut,” Nat. Pharmacy (2002). Vol. 6 (4), p. 1.
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