Bioavailability – absorption capacity
Attempts to define the controversial concept of bioavailability were made by several researchers. Recently it was agreed that the term shall describe“the fraction of active matterthat is transported acrossthe intestinal membrane into the bloodstream.
Someresearchers argue that the term bioeffectivity is more accurate and it includes the abilityof the active substance to travel to its target.
Maximum bioavailability of 100% according to the first definitionoccurs when asubstance is injected directly into the bloodstream.Most researchers use this concept for comparison. If a drug ( pharmaceutical)or a food supplement ( nutraceuticals) , for example, containing 500 mg of biactiveis orallyintake andafter an giventime, 400 mg of the same bioactive were found in the bloodstream itreflect a 80%bioavailability.
Omega fatty acids are part of a triglyceride (fat or oil) chemical structure..Structurally, a triglyceride has a glycerol backbone grafted withthree fatty acid lipophilic tails of fatty acids. Positional analysis indicate that the fatty acids can be grfrated (occupy) three positions known as:
SN1 – first position
SN2 – second position
SN3 – third position
The location of the “active” DHA on the glycerol backbone is very important for the improvement of absorption.
The fat( that is solubilized in the guts in the presence of bile salts)reachesthe intestinal ) does not cross the membrane in this form. The fat is partially hydrolyzed by the interfacial membrane enzymes to monoglycerides and free fatty acids.
The guts membrane can readily (fast) andquantitatively (fully) transport the monoglyceridewith the fatty acids attached in the SN2 position ) and in a slower if the acid is positioned in the SN2 or SN3
Supplements currently offered in the market, contain a low amountof DHA (maximum 30%) and it is distributedstatistically among the three SNpositions. Thus there is only a small percentage of DHA in the SN2 position.
AXOM3 contains over 70% of concentrated DHA and there are at least 80% of DHA in the SN2 position. AXOM3is termed re-esterified DHA or DHA-TG.
Triglyceride since it was designed and prepared enzymatically to include higher concentration of SN2 and to be very fluid molecule ( no crystallization at low temperatures). This structure causes significant improvement in the liquidity of the membrane (it does not crystallize even at minus 20 degreesCelsius). Due to the membrane high fluidity, the bioactive is easily transported across the membrane and also transported to the organs and cells. The omega fatty monoglyceridesare softeningthe membrane as well, increasing the permeability of the cell. This effect is one of the important qualities of the present DHA formulation, which other fatty acids,including EPA, do not possess to the same extent.
The researchers aim to obtain maximum DHA though the enzymatic process, in addition to quantitative transformation of SN2 to cause maximum bioavailabilityand better softening of the membrane.
The enzymatic process used to manufacture AXOM3, allows preferential grafting of the DHA to the SN2 byinteresterification process, while other products in the market are simple extraction of the fish fat composed of everythingthat exist in the fish, which is not in a preferentially transformed to the SN2 position, but only in statistically manner.
The manufacturing company chose to use tuna fishas a raw ingredients, because even though tuna is relatively low in omega fatty acids,it is rich in DHA in the SN2position.
The overall result is that the re-esterified AXOM3is quantitatively absorbed (98%bioavailability), while in other products absorption varies depending on the origin of the fish, fishing season, water temperature and more.
In some cases, the calculation of absorption are based on normalization of amount transported across the membrane and f 100% bioavailability calculations are based of absorption of free fatty or liver fat. The DHA ethyl esterare therefore absorption is of about 30%lower, whileAXOM3, which is DHA-TGis124%absorbed much above thenormalizedstandard.
*This study measured absolute values for oral ingestion of 150 mg.
Enzymatic modifications were made in the new AXOM3. As a result the amount of DHA in a triglyceride is at least 70%, while the rest of the fatty acidsare unsaturated (in comparison with the high percentage of saturated fatty acids in other products in the market today).
The newAXOM3 contains DHA that isquantitatively transformedin the SN2 position over 80%), while the two other positionsare also rich in DHA, which gives the product maximum absorption capacity (because of it being unsaturated and given at temperatures 20% lower).