Man's continuous endeavor to unravel mysteries of Nature and unearth resources that will boost or protect health, has brought out a variety of fruits, vegetables, nuts, legumes, spices, herbs, cereals etc with varying claims regarding their health value besides the inherent food value. Amongst the food constituents that gained prominence during the last two decades for their special ability to improve or protect health, antioxidants were the most studied because of their supposed role in neutralizing oxyradicals generated at the cellular level which accelerate cell destruction and cause debilitating diseases like cancer in humans. Polyphenols present in many foods are admired for their ability to work as antioxidants and some of the rich sources include tea, cocoa, coffee, fruits like strawberry, grapes, pomegranate, grapefruit, apple, kiwi fruit and lychee, many vegetables kale, broccoli, artichokes and brussel sprouts, nuts like pecan, walnut and sunflower seed and cereals such as oats and barley.
Though there has been lot of excitement regarding the beneficial role of polyphenols as a group of phytochemicals, many uncertainties cloud the claims by many commercial manufacturers of polyphenol ingredients extracted from natural sources. While many of these polyphenols have been found in many studies to be of proven health value, the findings have not been consistent due to many reasons. Lack of uniformity in technical analysis of various polyphenols present in different foods, large molecular weight and complex molecular structure of these compounds, insufficient knowledge about their fate in the GI tract of human beings, difference in the behavior of different polyphenols in different foods in different individuals consuming variable diets and extent of circulation of effective polyphenols in the blood etc make it difficult to predict their effect precisely.
Against the above background, promotion of Lychee fruit as a miracle source of polyphenols with 'fat bursting' properties, needs to be viewed with some caution. According to the available information Lychee polyphenols, extracted from the fruit and processed into smaller molecular weight polyphenols, supposed to be more readily absorbed in the body, are capable of reducing waist size by 3 cm, reducing the sub-cutaneous fat area by 15% and cans significantly lower the BMI besides improving insulin resistance amongst those pone to metabolic syndrome. Women with expanded waist line are believed to be susceptible to development of dementia in later stages of life and Lychee may become extremely popular with these subjects, if the claims are proved beyond any shadow of doubt.
The process of reducing the polyphenol chain length, called oligomerization, is supposed to generate monomers and smaller molecular weight oligomers which are absorbed 3-5 times more efficiently. Whether the fat bursting property comes from Lychee itself or by the process of oligomerization is not clear. Of course Lychee is one of three top polyphenol containing fruits, others being strawberry and grapes. Also not known is whether consuming the fruit as fresh or as extracted juice will confer same benefits. However, if the claims are true, probably Lychee may become the most sought after tropical fruits in the world.
Oligonol, a commercial product made from Lychee extract, is being promoted as an elixir of life with some supporting evidence and probably may become a GRAS chemical because it is obtained from a natural fruit which has more than 2000 years of history, being the favorite fruit of the Tang Dynasty of ancient China. Nutritionists and health pundits always maintain that, for best effect of any phytochemical in the body, blends of natural foods containing different nutrients are the most desirable route and isolated ingredients may not have the same effect always with all the people. Oligonol from Lychee must be subjected to further scientific scrutiny before considering it as a universal health supplement.