Lecithin is mostly a mixture of glycolipids, triglycerides, and phospholipids (e.g. phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol). However, in biochemistry, lecithin is usually used as a synonym for pure phosphatidylcholine, a phospholipid which is the major component of a phosphatide fraction which may be isolated from either egg yolk (in Greek lekithos - λεκιθος) or soy beans from which it is mechanically or chemically extracted using hexane.]
Lecithin is commercially available in high purity as a food supplement and for medical uses.
In biology
Nervous and circulatory lecithin is produced by the liver if the diet is adequate. It is needed by every cell in the body and is a key building block of cell membranes; without it, they would harden. Lecithin protects cells from oxidation and largely comprises the protective sheaths surrounding the brain.
What Claims Do Lecithin Supplement Suppliers Make About Lecithin's Functions?
Lecithin is promoted as a quick fix for weight loss, as well as many other diseases and ailments. Lecithin supplement producers claim that lecithin has a beneficial role in:
Cardiovascular health Liver and cell function fat transport and fat metabolism reproduction and child development physical performance and muscle endurance cell communication improvement in memory, learning and reaction time relief of arthritis healthy hair and skin treatment for gallstones
None of the advertisements on the web have real scientific evidence for the effectiveness of lecithin in weight loss and fat metabolism, yet this is the supplement producers' main selling point for lecithin. The rational behind the fat metabolizing claim is due to lecithin's inherent role as an emulsifying agent. Producers claim that this characteristic of lecithin functions to break down the fat and disperses it in water and/or in our blood stream, allowing the fat to be flushed out of the body.
Does Scientific Research Support These Claims?
There is no scientific research that shows that lecithin aids in weight loss. In fact, lecithin supplements may actually cause weight gain due to the fact that it contains fatty acids and is thus highly caloric. There is just no validity to the rationale behind the weight loss claim. Lecithin makes sure that the fat and cholesterol that is travelling through the blood stream stays solvent in the water so that it will not attach to the artery walls. Even though lecithin does disperse fat in water and keeps fat from clogging the cardiovascular system, this does not mean that the subcutaneous fat that we associate with being overweight is just dissolved and flushed out by lecithin.
Humans get lecithin from cell production and from the nutrients in our diets. The estimated amount of lecithin in a human's diet is 50mg, which is sufficient for the body's proper functioning. Any healthy person whom consumes a well-balanced diet does not need to take lecithin supplements. But, what is considered a "well-balanced" diet? Not much is known about the relationship between the average person's dietary patterns, food processing and lecithin intake. Further studies of lecithin intake in the American diet would prove beneficial to resolve this question of the necessity of lecithin supplements. But "with our present available information there is no way of knowing whether long-term administration of lecithin at low doses has either a good, or detrimental effect". (Schenider, 181)
It is more reasonable to include extra lecithin in one's diet for health benefits such as decreased cholesterol levels or gallstone problems rather than for weight loss. But even research on lecithin's effects on these other ailments are inconclusive and irreplicable. Most of the scientific research conducted has been to test lecithin's effectiveness with neurological and liver diseases. Studies show conflicting results when examining lecithin's role in memory, probably due to the numerous uncontrollable and untestable variables involved with memory.
Many studies have been administered to test lecithin's effect on Alzheimer's disease. Lecithin produces the neurotransmitter acetylcholine which enables communication and signal-transmission between brain cells. Alzheimer's disease can be caused by a change in production of acetylcholine. Many speculate that an increase in lecithin will prompt brain cells to produce more acetylcholine, thus improving memory. Lecithin and choline have been tested to do this and neither has been proven to be effective. In most of these studies, a portion of subjects improved markedly, while others were not helped at all. (Zeisel, 334)
Lecithin "may lower cholesterol since lecithin is composed of polyunsaturated fatty acids, but studies have been inconclusive". (Thrive Online) "Although it is clear that lecithin administration can be beneficial for humans with tardive dyskinesia (a neurological disorder), and although there is reason to believe that normal memory can be influenced by the choline (found in lecithin) content of the diet, evidence available at this time does not justify the widespread us of lecithin for improved memory by the healthy general public" (Zeisel, 323). The only proven benefit and suggested use of lecithin or choline supplements is for those whom are taking niacin or nicotinic acid to treat high cholesterol. The niacin treatment can deplete choline, so an increased amount of lecithin or choline is necessary in the diet.
What Are The Side Effects From Taking Lecithin Supplements?
Most people do not feel any side effects when taking 10 to 30 grams per day of lecithin supplements. (Zeisel, 332) But in higher doses, lecithin supplements could cause gastrointestinal problems, diarrhea, weight gain, a rash and headache, nausea, vomiting, dizziness, and/or a "fishy" body odor.
Conclusion
Lecithin has received widespread attention recently for its speculative treatment of many diseases and obesity. It has even been marketed as a product for those whom want to get rid of a little excess fat and improve muscle endurance. There is no proven evidence that suggests lecithin supplements have any effect in these areas, although studies continue to search for lecithin's role in these areas. Lecithin supplements at this time are not recommended for anyone, except for people taking niacin. Any diet or supplement that promises a quick fix to weight loss either has no scientific proof, and/or is probably a serious health risk. Lecithin supplements for weight loss fit into both of these categories. The more we search for answers, the more we come back to the same solution. The only safe, proven way to lose weight is through a healthy, low-fat diet with regular exercise. All the lecithin one needs for proper biological functioning is supplied in a healthy diet and by our own cells.
References
Barbeau, Andre M.D., John H. Growdon, M.D., Richard J. Wurtman, Nutrition and the Brain; Choline and Lecithin in Brain Disorders, (1979) Vol. 5, Raven Press, NY, 73, 76, 83, 113, 444.
Hanin, Israel, G. Brian Ansell, Lecithin : Technological, Biological, and Therapeutic Aspects, (1987), Plenum Press, NY, 180, 181.
Szuhaj, Bernard F., Gary R. List, Lecithins (1985), American Oil Chemists' Society, 323, 324, 326, 331-337.
Langer, Stephen, "Ekectrify your memory with brain-boosting nutrients", (June 1997) Better Nutrition, Atlanta, 36-47.
As a food additive
Lecithin is regarded as a well tolerated and non-toxic surfactant. It is approved by the United States Food and Drug Administration for human consumption with the status "Generally Recognised As Safe". Lecithin is an integral part of cell membranes, and can be totally metabolized, so it is virtually non-toxic to humans. Other emulsifiers can only be excreted via the kidneys.
Lecithin is used commercially for anything requiring a natural emulsifier and/or lubricant, from pharmaceuticals to protective coverings. For example, lecithin is the emulsifier that keeps chocolate and cocoa butter in a candy bar from separating.
Various studies (Brook et al. 1986, Spilburg et al. 2003) indicate that soy-derived lecithin may positively affect cholesterol and triglyceride levels in the blood.
Commercial lecithin, as used by food manufacturers, is a mixture of phospholipids in oil. The lecithin is obtained by degumming the extracted oil of oil seeds. The lecithin is a mixture of various phospholipids, and the compositions depends on the origin of the lecithin. A major source of lecithin is soybean oil. Due to the EU-requirement to declare the addition of allergens in foods a gradual shift to other sources of lecithin, e.g., sunflower oil, is taking place.
The main phospholipids in lecithin from soya and sunflower are phosphatidyl choline, phosphatidyl inositol, phosphatidyl ethanolamine and phosphatidic acid. They are often abbreviated to PC, PI, PE and PA respectively. To modify the performance of lecithins, i.e., to make it suitable for the product to which it is added, it may be hydrolysed enzymatically. In hydrolysed lecithins, a portion of the phospholipids have one fatty acid removed by phospholipase. Such phospholipids are called lyso-phospholipids. The most commonly used phospholipase is phospholipase A2, which removes the fatty acid at the sn-2 position.
In margarines, especially those containing high levels of fat (>75%), lecithin is added as 'anti-spattering' agent: it helps in suppressing spattering during shallow frying. Lecithin is admitted by the EU as a food additive and is designated by E number E322.
Lecithins may also be modified by a process called fractionation. During the fractionation process lecithin is mixed with an alcohol (usually ethanol). Some phospholipids have a good solubility in ethanol (e.g. phosphatidylcholine), whilst most other phospholipids do not dissolve well in ethanol. The ethanol is separated from the lecithin sludge, after which the ethanol is removed by evaporation, to obtain a phosphatidylcholine enriched lecithin fraction.
Compatibility with specialized diets
Egg-derived lecithin may be a concern for those following certain specialized diets. Under kashrut it is considered pareve (neutral, e.g., may be mixed with both meat and dairy). Under sharia, lecithin derived from plants, egg yolks or Halal animals is allowed, otherwise it is prohibited. There is no general agreement among vegetarians concerning egg-derived lecithin, but vegans especially would try to avoid consuming it. Egg lecithin itself is not a concern for those on a low cholesterol diet, but if not purified before being used as a food ingredient, it could contribute significantly to the overall cholesterol content of the food.
See also
References
- Brook JG, Linn S, Aviram M. Dietary soya lecithin decreases plasma triglyceride levels and inhibits collagen-and ADP-induced platelet aggregation. Biochem Med Metab Biol 1986;35:31-9. PMID 3778675.
- Spilburg CA, Goldberg AC, McGill JB, Stenson WF, Racette SB, Bateman J, McPherson TB, Ostlund RE Jr. Fat-free foods supplemented with soy stanol-lecithin powder reduce cholesterol absorption and LDL cholesterol. J Am Diet Assoc 2003;103:577-81. PMID 12728215.
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