I am reading about fatty acids online and I chanced upon an article entitled The Oiling of America. Valid points are discussed in this article for example:
Cholesterol is needed for proper function of serotonin receptors in the brain. Serotonin is the body's natural "feel-good" chemical. This explains why low cholesterol levels have been linked to aggressive and violent behavior, depression and suicidal tendencies.
I also once came across one site which is a Filipino counterpart of this, which advocates the use of coconut oil and its by-products as health supplement.
In the end, IMHO, all of this is just a marketing war. Of course at this time, the big American companies win it. Look at the percentage market share and price of coconut oil and compare it with soya oil or corn oil and you'll see what I mean. Bottom line, the people of the world losses and the big companies win!
Things you don't want to know:
Grehlin: A Peptide Hunger Hormone
Grehlin is a peptide hormone known as a circulating hunger hormone. It increases food intake and increases fat mass. It exerts its action at the level of the hypothalamus. Aside from appetite stimulation, it also activates the mesolimbic cholinergic-dopaminergic reward link. This link communicates the pleasure-seeking and reinforcing aspects of natural rewards such as food as well as that of addictive substances.
Its name is from growth hormone-releasing peptide and it was discovered in 1999 in Japan by Masayasu Kojima and his colleagues Hosoda, Date, Nakazato, Matsuo, and Kangawa.
This hormone is produced by P/D1 cells lining the fundus of the stomach that stimulate appetite. In rodents, X/A-like cells produce ghrelin.
Ghrelin levels increase before meals and decrease after meals. It is considered the counterpart of the hormone leptin, produced by adipose tissue, which induces satiation when present at higher levels. It also stimulates the secretion of growth hormone from the anterior pituitary gland. In some bariatric procedures, the level of ghrelin is reduced in patients, thus causing satiation before it would normally occur.
The discovery of this hormone may lead to the development of anti-obesity vaccine which may be used in humans as an aid in keeping fit or in animals to decrease expenses on feeds or in decreasing fat deposition.
Xenoextrogens: Environmental estrogens
Estrogens are a group of steroid compounds. They are important in the estrous cycle, and they function as the primary female sex hormone.
Xenoestrogens are compounds that mimic the effect of natural estrogens. They are synthetic compounds that are released to the environment because of industrialization and other related activities. The problem is that they are now everywhere and has recently been implicated in various reproductive impairments in wildlife. Hence, they may potentially exert more effect to humans in the future.
Examples of xenoestrogens are:
1. EE2 (17α-ethynylestradiol). This is a major component of birth control pills and is excreted by women via urine. It is believed that this contaminates sewage water.
2. DDT (Dichloro-Diphenyl-Trichloroethane). This is an insecticide widely used before against mosquitoes. Rachel Carson’s Silent Spring was published and was against its use. It was banned in the US in 1972 but is still being used in third world countries.
3. PCBs (polychlorinated biphenyls) - PCBs are used in electrical oils, lubricants, adhesives, paints.
Xenoestrogens come from a variety of sources. The problem with them is that they may be accumulated and may even be transferred from one generation to the next. They also exert effect even at very low levels. They have been traced to be associated with reproductive problems and are also associated with breast cancer.
Mannan-oligosaccharides
Mannan-oligosaccharides are used in animal feed to encourage gastrointestinal health and performance. They are normally obtained from the yeast cell walls of Saccharomyces cerevisiae. When consumed, the undigested portion serves as food for the intestinal microflora (as a prebiotic). Prebiotics produce many beneficial substances, including short-chain fatty acids and B-vitamins. They also promote further absorption of some minerals that have escaped the small intestine, including calcium and magnesium.
Oligosaccharides have the chemical formula Cn(H2O)n-1 where n is usually between 200 and 2500. They are made up of many monosaccharides joined together by glycosidic bonds. Mannan is a plant polysaccharide that is a polymer of the sugar mannose.
Among the beneficial effects noted on pigs are:
o Efficient nutrient transfer from sow to piglets
o Higher weaning weights
o Fast return to estrus
o Economic advantage
o Better pre-weaning livability
o Reduced use of therapeutic treatments
o Finish pigs faster to market
o Natural meat marketability
I believe that mannan-oligosaccharides need to be exhaustively studied so that utilization in farm animals can be optimized.
High Performance Liquid Chromatography
High Performance Liquid Chromatography is commonly used to separate and identify organic molecules, biomolecules, ions and polymers. They are separated on the basis of their differential adsorption characteristics by passing the solution to be analyzed through a column. The components can be separated on the basis of their partition coefficients, polarities or sizes, depending on the type of column used. HPLC is currently the most important chromatographic method for analysis because it is capable of rapid, specific, sensitive and precise measurements. Often, samples could be analyzed directly in HPLC.
Procedure:
The basic operating principle of HPLC is to force the analyte through a column of the stationary phase (usually a tube packed with small round particles with a certain surface chemistry) by pumping a liquid (mobile phase) at high pressure through the column. The sample to be analyzed is introduced in small volume to the stream of mobile phase and is retarded by specific chemical or physical interactions with the stationary phase as it traverses the length of the column. The amount of retardation depends on the nature of the analyte, stationary phase and mobile phase composition. The time at which a specific analyte elutes (comes out of the end of the column) is called the retention time and is considered a reasonably unique identifying characteristic of a given analyte. The use of pressure increases the linear velocity (speed) giving the components less time to diffuse within the column, leading to improved resolution in the resulting chromatogram. Common solvents used include any miscible combinations of water or various organic liquids (the most common are methanol and acetonitrile). Water may contain buffers or salts to assist in the separation of the analyte components, or compounds such as Trifluoroacetic acid which acts as an ion pairing agent.
A further refinement to HPLC has been to vary the mobile phase composition during the analysis, this is known as gradient elution. A normal gradient for reversed phase chromatography might start at 5% methanol and progress linearly to 50% methanol over 25 minutes, depending on how hydrophobic the analyte is. The gradient separates the analyte mixtures as a function of the affinity of the analyte for the current mobile phase composition relative to the stationary phase. This partitioning process is similar to that which occurs during a liquid-liquid extraction but is continuous, not step-wise. In this example, using a water/methanol gradient, the more hydrophobic components will elute (come off the column) under conditions of relatively high methanol; whereas the more hydrophilic compounds will elute under conditions of relatively low methanol. The choice of solvents, additives and gradient depend on the nature of the stationary phase and the analyte. Often a series of tests are performed on the analyte and a number of generic runs may be processed in order to find the optimum HPLC method for the analyte - the method which gives the best separation of peaks.
Reversed phase chromatography
Reversed phase HPLC (RP-HPLC) consists of a non-polar stationary phase and an aqueous, moderately polar mobile phase. One common stationary phase is a silica which has been treated with RMe2SiCl, where R is a straight chain alkyl group such as C18H37 or C8H17. The retention time is therefore longer for molecules which are more non-polar in nature, allowing polar molecules to elute more readily. Retention Time (RT) is increased by the addition of polar solvent to the mobile phase and decreased by the addition of more hydrophobic solvent. Reversed phase chromatography (RPC) is so commonly used that it is not uncommon for it to be incorrectly referred to as "HPLC" without further specification. The pharmaceutical industry regularly employs RPC to qualify drugs before their release.
RPC operates on the principle of hydrophobic interactions, which result from repulsive forces between a polar eluent, the relatively non-polar analyte, and the non-polar stationary phase. The binding of the analyte to the stationary phase is proportional to the contact surface area around the non-polar segment of the analyte molecule upon association with the ligand in the aqueous eluent. This solvophobic effect is dominated by the force of water for "cavity-reduction" around the analyte and the C18-chain versus the complex of both. The energy released in this process is proportional to the surface tension of the eluent (water: 73 erg/cm2, methanol: 22 erg/cm2) and to the hydrophobic surface of the analyte and the ligand respectively. The retention can be decreased by adding less-polar solvent (MeOH, ACN) into the mobile phase to reduce the surface tension of water. Gradient elution uses this effect by automatically changing the polarity of the mobile phase during the course of the analysis.
Structural properties of the analyte molecule play an important role in its retention characteristics. In general, an analyte with a larger hydrophobic surface area (C-H, C-C, and generally nonpolar atomic bonds, such as S-S and others) results in a longer retention time because it increases the molecule's nonpolar surface area, which is non-interacting with the water structure. On the other hand, polar groups, such as -OH, -NH2, COO- or -NH3+ reduce retention as they are well integrated into water. Very large molecules, however, can result in an incomplete interaction between the large analyte surface and the ligands alkyl chains and can have problems entering the pores of the stationary phase.
RT increases with hydrophobic - nonpolar - surface area. Branched chain compounds elute more rapidly than their corresponding linear isomers because the overall surface area is decreased. Similarly organic compounds with single C-C-bonds elute later than the ones with a C=C or C-C-triple bond, as the double or triple bond is shorter than a single C-C-bond.
Aside from mobile phase surface tension (organizational strength in eluent structure), other mobile phase modifiers can affect analyte retention. For example, the addition of inorganic salts causes a moderate linear increase in the surface tension of aqueous solutions (ca. 1.5 erg/cm2 pro Mol for NaCl, 2.5 erg/cm2 pro Mol for (NH4)2SO4), and because the entropy of the analyte-solvent interface is controlled by surface tension, the addition of salts tend to increase the RT. This technique is used for mild separation and recovery of proteins and protection of their biological activity in protein analysis (hydrophobic interaction chromatography, HIC).
Another important component is the influence of the pH since this can change the hydrophobicity of the analyte. For this reason most methods use a buffering agent, such as sodium phosphate, to control the pH. A volatile organic acid such as formic acid or most commonly trifluoroacetic acid is often added to the mobile phase, if mass spectrometry is applied to the eluent fractions. The buffers serve multiple purposes: they control pH, neutralize the charge on any residual exposed silica on the stationary phase and act as ion pairing agents to neutralize charge on the analyte. The effect varies depending on use but generally improve the chromatography.
Reversed phase columns are quite difficult to damage compared with normal silica columns, however, many reversed phase columns consist of alkyl derivatized silica particles and should never be used with aqueous bases as these will destroy the underlying silica backbone. They can be used with aqueous acid but the column should not be exposed to the acid for too long, as it can corrode the metal parts of the HPLC equipment. The metal content of HPLC columns must be kept low if the best possible ability to separate substances is to be retained. A good test for the metal content of a column is to inject a sample which is a mixture of 2,2'- and 4,4'- bipyridine. Because the 2,2'-bipy can chelate the metal it is normal that when a metal ion is present on the surface of the silica the shape of the peak for the 2,2'-bipy will be distorted, tailing will be seen on this distorted peak.