The research team, which had previously simulated the effects of static magnetic fields on simple inorganic molecules, alkanols, carbohydrates and porphyrins, turned this time to the lipids that matter most for life. They examined seven eighteen-carbon fatty acids: stearic acid, the fully saturated straight chain; oleic, linoleic and linolenic acids, the cis-unsaturated acids common in plant oils; elaidic and vaccenic acids, the trans-unsaturated acids; and trans-linolenic acid, the fully trans polyunsaturated variant. Alongside these they studied five caproyl glycerides, from monoglycerides through diglycerides to the triglyceride that represents the major form of energy storage in animals and plants. These molecules co-constitute biological membranes, cooperate in skin elasticity and dominate the functional properties of foodstuffs, making them a rational focus for any assessment of magnetic risk.

The simulations were performed entirely in silico, in what the authors call the computer vacuum, using advanced computational methods. Molecular structures were drawn with the Fujitsu SCIGRESS 2.0 software, oriented with their principal symmetry axes along the x-axis of a Cartesian system and enclosed in a three-axial ellipsoid. The molecules were then optimized with Gaussian 0.9 software equipped with the 6-31G** basis set, which computed bond lengths, dipole moments, heats of formation, bond energies and total energies. In the decisive step, the influence of static magnetic fields of 0.0, 0.1, 1, 10 and 100 AMFU, an Arbitrary Magnetic Field Unit in which one AMFU exceeds 1000 tesla, was computed with the Amsterdam Modelling Suite software and the non-relativistic orbital momentum L-dot-B method. The field was fixed along the x-axis with its south pole on the left side of the molecule.

The headline finding is that static magnetic fields polarize lipid molecules in a way that depends strongly on the applied flux density, and that at low strengths the fields neither ionize the molecules nor break their valence bonds. At 0.1 and 1 AMFU the molecules survive intact, but their heats of formation rise steadily, evidence of progressive destabilization. Stearic acid, for example, climbs from a heat of formation of minus 560 kilojoules per mole in the field-free state to minus 511 at 1 AMFU, while its dipole moment grows from 3.42 to 3.84 debye. Every lipid acid and glyceride studied showed the same pattern of increasing heat of formation and increasing dipole moment with rising field strength, confirming that the molecules become less stable and more polar as the magnetic field intensifies.

What struck the researchers most was the irregularity of these changes. The orders in which the molecules destabilized bore no relationship to the number of double bonds or the conformation of the carbon chain. Among the fatty acids, trans-linolenic acid destabilized most, followed by linoleic, linolenic, elaidic, vaccenic, stearic and oleic, while the dipole moments declined in a completely different order led by vaccenic acid. Among the glycerides, the triglyceride destabilized most but the dipole moment sequence was again independent of the degree and position of esterification. The explanation, the authors argue, lies in the ability of these flexible molecules to twist out of the plane initially established by the magnetic field and to squeeze their fragments around certain bonds, creating through-space interactions between atoms that involve van der Waals bonding and dispersion forces.

At the highest simulated strengths the situation turns destructive. Flux densities of 10 and 100 AMFU broke some carbon-hydrogen and carbon-carbon bonds in several of the molecules under consideration. In stearic acid, bonds such as C10-C11, C17-H54, C2-H24 and C1-H20 elongated well above 2 angstroms, the calculated equivalent of ceasing to exist as chemical bonds. Oleic acid survived exposure to 10 AMFU but fractured at 100 AMFU, splitting nine separate bonds. Linolenic acid lost the C19-H49 bond at 10 AMFU and the C1-H39 bond at 100 AMFU, while vaccenic and trans-linolenic acids deteriorated only at the highest strength. When a valence bond disintegrates in this way, the binding electron pair splits into two unpaired electrons and a pair of highly chemically active radicals is generated, species that can bind to ambient molecules and change their chemical structure and biological activity.

Only one molecule in the entire study underwent the cis-trans conversion that magnetic fields are known to provoke. Elaidic acid, the trans-monounsaturated acid, transformed from its trans-conformation into the cis-conformer when exposed to fields above 1 AMFU. The authors note that this ability of static magnetic fields to accelerate the transition of a conformer from cis to trans, or in this singular case the reverse, can significantly affect the oxidation of unsaturated fatty acids, because the auxiliary enzyme enoyl-CoA isomerase that participates in the beta-oxidation pathway works precisely by converting cis-conformers into trans. Vaccenic acid, whose double bond sits at a different position along the chain, resisted any such isomerization even at 100 AMFU, demonstrating how sensitive the outcome is to molecular structure.

The metabolic consequences of these distortions depend on which atoms the field affects most. The atoms of the carboxylic group proved the most susceptible to the magnetic field in every fatty acid studied. The first step of fatty acid metabolism, in which coenzyme A bonds to the carbonyl carbon atom, is favoured by a high positive charge density on that atom and a highly polarized carbon-hydroxyl bond. The simulations show that the field shifts these charge densities irregularly: in stearic acid a field of 0.1 AMFU weakly stimulates the first metabolic step while 1 AMFU inhibits it; in oleic acid fields from 0.1 to 10 AMFU inhibit the first step; in trans-linolenic acid 0.1 AMFU strongly stimulates the first step while 10 AMFU inhibits it. For the glycerides, whose metabolism usually involves hydrolysis by lipases, the charge density on the carboxylic carbon atom varied irregularly with field strength, and only in the triglyceride did the field, regardless of its value, always stimulate hydrolysis.

The authors identify two physical factors behind the susceptibility of molecules to static magnetic fields. The first is the Lorentz force, which acts on moving electrons and at high intensity influences the natural geometry of orbitals, an effect too difficult to include fully in the calculations. The second is the ceasing of the coherence of the binding electron pair, which persists despite electrostatic repulsion by magnetic interactions. A very strong external magnetic field competes with the mutual fields of the paired electrons, gradually weakening their pairing until the bond expands and disintegrates on exceeding a critical length. Because the binding electron pair is the fundamental element of the chemical bond, this gradual splitting is what ultimately generates the radicals observed at high field strengths.

The bottom line of the study is a nuanced risk picture rather than a simple warning. Depending on molecular structure and applied flux density, static magnetic fields either stimulate or inhibit the metabolic processes of the lipids under study, and the direction of the effect depends irregularly on field strength. At the low flux densities typical of everyday exposure, the simulated fields distort and polarize lipid molecules without breaking them, shifting the charge densities that govern enzymatic reactions in ways that could speed up or slow down metabolism. At the extreme strengths of 10 AMFU and above, equivalent to many thousands of tesla, the fields begin to snap valence bonds and generate free radicals. As magnetic pollution of the environment grows and the food industry increasingly exploits static magnetic fields to build functional properties into foodstuffs, the authors argue that understanding these molecular interactions is an essential step toward recognizing the potential risk that such fields pose to flora and fauna.

Subject of Research: Biophysics

Article Title: Potential risk resulting from the influence of static magnetic field upon living organisms. Numerically simulated effects of the static magnetic field upon fatty acids and their glycerides

Article References: Ciesielski, W., Kołoczek, H., Oszczęda, Z., Soroka, J. A., & Tomasik, P. (2023). Potential risk resulting from the influence of static magnetic field upon living organisms. Numerically simulated effects of the static magnetic field upon fatty acids and their glycerides. BioRisk, 19, 1-24. https://doi.org/10.3897/biorisk.19.96250

Image Credits: AI Generated

DOI: 10.3897/biorisk.19.96250

Keywords: static magnetic field, fatty acids, glycerides, lipids, molecular simulation, computational chemistry, free radicals, BioRisk, Potential, risk, resulting, influence