Mineral Taste Testing: The Science Behind It

When Professor Kenneth Glander, of Duke University’s Primate Center, keeps an eye on his horde of lemurs, he is hardly concerned that the animals could poison themselves on the myriad food choices available so distant from their native habitat.  He holds that the lemurs are smart enough to know what to eat and what to avoid.  After all, living in the wild offers a minefield of the good, the bad, and the bitter. Wild things are pretty good at picking their way through the maze of foods and poisons, and even at choosing a dose of something curative for what ails them.  Dr. Glander is one of the few primatologists to publish on the intricacies of animal food choices, noting that humans are no different in using the nose to discern what we need and how much.  To test the lemurs, he offered them ten kinds of local leaves: five that were considered highly digestible and five that inhibited digestion, none being toxic.  The animals’ final choices gave them the highest nutrient values and the lowest tannin content. This discernment he attributed to the keen perception of taste and smell, physiologically partnered by the Jacobson’s organs that connect the mouth and nasal passages.  This vomeronasal (VNO) organ is part of the accessory olfactory system and contains sensory neurons excited by chemical stimuli, offering a kind of instant chemical analysis. Common to many vertebrates, the VNO in some mammals contracts to pump and to draw in the scents.  This can be seen when a cat, for example, tilts its head after finding an odorant and curls its upper lip while wrinkling its nose.

About one percent of gene sequencing in humans is devoted to smell and taste, the least understood of the senses. Of mineral deficiencies in particular, that of zinc is more widespread than appreciated.  Its depletion is associated with disorders that include diabetes, food sensitivities and allergies, delayed wound healing and recurrent infections, among others. Fingernail ridges are an overt sign, and may be linked to infertility, arthritis, hair loss, learning disorders or eczema.  An interesting way to determine zinc sufficiency is to perform the zinc taste test developed by chemistry professor Derek Bryce-Smith, who was among the first scientists to describe the dangers of tetraethyl lead, the anti-knock gasoline additive. But it was his examination of N-P-K fertilizers that found an association with zinc deficiency.  His test requires placing a small amount of zinc sulfate in the mouth and determining if you can taste it. If you can’t, you are zinc deficient (Bryce-Smith, 1986). A study of pregnant women given 200 mg of ZnSO4daily until parturition assessed zinc status using the taste test, finding a sound correlation with serum zinc levels (Garg, 1993).   At the University of Pennsylvania, rats were fed a calcium or sodium deficient diet for a few weeks, other nutrients being normal.  Later offered diets containing the mineral of which they were deprived, those missing calcium preferred calcium-laden comestibles and those missing sodium preferred that, both rejecting sugar-flavored anything (Coldwell, 1993).  These results provide evidence for the existence of innate mineral appetites as an expression of need. Our sense of taste comes from the part of the brain called the parabrachial nucleus, located at the junction of the midbrain and pons, which transmits signals to the medulla oblongata, the spinal cord, the hypothalamus and the amygdala.  It was identified as a taste relay in the early 1970’s, and compartmentalized by subnuclei into dealing with different aspects of taste, visceral sensation, likes and dislikes. In rodents it is used in parallel processing of taste and hedonic information; in humans and other primates, serial processing precedes hedonics. Changing physiological conditions affect the neurons that influence feeding behavior in rodents, while in primates independent cognitive analysis directs food selection (Scott, 2009). Parallel processing is the ability to carry out multiple operations or tasks simultaneously, while assessing stimuli of differing quality.  This becomes most valuable in vision, where the brain divides what it sees into four components—color, shape, motion and depth. Serial processing, on the other hand, applies memories to incoming presentations (one at a time) to make comparisons and then decisions.  If the serial processing is self-terminating, comparisons stop abruptly when the target is found, after which a response is generated. If the processing is exhaustive, comparisons continue until the entire set is compared; then the response is made. There is also a behavioral component of acceptance versus rejection that helps humans to protect themselves against poisons. 

Besides informing the individual about the external world, taste connects a perception with information about the internal environment.  Molecules act on specialized sensory cells in various regions of the mouth, thus triggering signals which, in turn, are relayed to those areas of the limbic system associated with the parabrachial nucleus. Supplemental minerals are associated with different absorptive capacities, depending on physiological, biochemical and even hormonal characteristics of the user.   But a mineral’s bioavailability depends also on its valence, spin, mass, atomic number, isotopes and other properties. Being a chemical factory, the body has to take in the raw materials to manufacture the chemicals it needs to perform all its functions.  For a mineral to be usable, it has to be absorbed and find its way into the appropriate cells. Once there, it usually needs conversion to a utile form, after which it is eliminated if found unnecessary. Some toxic minerals are very easily absorbed and assimilated, even through the skin.  So, because potential mineral sources differ and because their deficiencies or excesses can cause concerns, their individual characters need to be evaluated. When mineral stores are low, the intestine will upregulate the eagerness with which a nutrient is accepted.  With adequate or elevated levels, the opposite occurs. On a molecular basis, this regulation may be conveyed by intraluminal binding ligands, by cell surface receptors, by various carrier or storage proteins, or by the machinery of transmembrane transport. The bulk of mineral absorption occurs in the small intestine—in the duodenum—in some cases, such as with calcium, by more than one mechanism.  Active Ca absorption occurs only in duodenum when Ca intake is less than optimal. Here, Ca is imported into the enterocyte, is transported across the cell, and is exported to extracellular fluid and blood. Voltage-insensitive channels pump Ca out of the cell by way of calcium-ATPase. The carrier protein, calbindin, the synthesis of which depends on vitamin D, enhances transport across the epithelial cell.

Passive absorption of Ca occurs in the jejunum and ileum when dietary Ca levels are high. Here, ionized Ca diffuses through the tight junctions into the basolateral spaces of enterocytes, and then into the blood. The minerals in foods are normally present in low concentrations, so the body has devised active transport mechanisms to help guarantee absorption. Generally, there is an inverse relationship between mineral availability and absorption.  Therefore, the more you take, the less you absorb. Small molecular weight ligands, such as amino acids and other organic acids, have the capacity to increase solubility and to facilitate absorption, but liquefied mineral supplements, being already dissolved, are immediately bioavailable.  Moreover, being acidified by design, they display increased availability (Vinson, 1988). The bottom line is that the minerals with the greatest solubility have the greatest bioavailability. If the food supply were trustworthy, it might be possible to get a day’s worth of minerals from our diets.

But that also supposes a person will eat a healthy regimen without processed foods and rancid supermarket fats and oils.  It also means eliminating added sugars, avoiding aflatoxin-laden grains, and being faithful to grass-fed, hormone-free meats.  What’s the big deal about minerals? Alone, they are inactive chemical elements. In the body, however, they light up either as structural elements of teeth and bone, for example, or as functional partners in hormones or electrolytes.  Without them, there can be no muscle responses, no transmission of messages through the nervous system, and poor maintenance of physiological pH and food metabolism. The body can’t make them, so they have to come from what we eat. The macro-minerals are needed in amounts of 100 milligrams a day, generally listed as calcium, phosphorus, magnesium, sodium, chloride and potassium.  Even on a good day, their RDI’s may be hard to achieve from food. Dr. Donald Davis, at the University of Texas Biochemical Institute, tracked changes in food quality of forty-three garden crops over the past few decades and reported statistically reliable declines in nutritional value (Davis, 2004).   Iron, selenium, zinc, chromium, copper, molybdenum, silicon, boron, cobalt, sulfur and a few others, like iodine, are cited as micro-minerals, needed in far lesser amounts.   Each mineral, macro and micro, has a job to do and none is more or less important than any other. In some instances, minerals work as a team. To contract a muscle cell, calcium tells sodium to do its magic.  To relax that cell, magnesium directs potassium to let go.

To learn more about mineral balance and its relation to optimal health, read the BodyBio Research: The Importance of Minerals,  BodyBio Research: Focus: Iodine Deficiency. One unheralded and obscure truth about minerals is that they have an electrical character to their individual personalities. There exist natural electrical potentials, electrical conductivity and resistivity, and a dielectric constant. If push comes to shove, we may even mention magnetic permeability.

Of these traits, conductivity is deemed the most important. In colloid chemistry you may hear of Zeta Potential, a.k.a. electrokinetic potential.  This may be seen when a solution of electrical resistivity and viscosity is forced through a porous medium.  Or you may hear of diffusion potential, a difference generated across a membrane because of a concentration difference of an ion, where the membrane is permeable to the ion.  Then, of course, there has to be equilibrium potential that exactly balances the tendency for diffusion caused by concentration difference. Not all minerals share these characteristics because not all are metals or metalloids, such as sulfur and phosphorus.  But the liquefied minerals available from BodyBio and other top shelf supplement manufacturers have these electrical properties.

Without a physiological sensorium with which to identify the display of such an electrical behavior, this chart would make little sense.

However, there are receptors on oral surfaces—lingual, buccal, palatal and pharyngeal—that respond to the presence of each mineral and the intensity with which it announces itself by identifying an electrical attribute.  This does not necessarily mean that potassium tastes like potassium and selenium tastes like selenium. It means only that the probes of the body’s volt-ohm meter are identifying an open or a closed circuit. If, for example, the body is replete in magnesium, the receptors will be able to detect a corresponding conductivity-resistivity and gustatorily classify it as having a metallic taste or not, largely due to ion concentration. It’s as if the receptors were tiny straws filled to the top with electro-chemical complexes that respond immediately to the impingement of compatible mineral molecules.  Diverse channels and G-protein-coupled receptors activate taste transduction in response to various compounds, changing neurotransmitter release via depolarization or other activity. Different sweeteners, for example, activate enzymes that open or close appropriately related channels, depending on their synthetic or natural composition. 

Uniquely, several pathways for perception may occupy the same cell. We also need to understand that there are concentration thresholds for detecting a single taste response—the presence of a mineral in this case. The ongoing presence of a mineral may shut off its perception and that of other molecules that share a receptor. That offers a rationale for changing the stimulus in a timely manner, as is expected with the BodyBio Mineral Taste test.  


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