Essential Fatty Acids
Most fatty acids can be naturally produced in the normal mechanism of human body. The body is capable of producing monounsaturated fatty acids (using a double bond at the point of omega-9) and saturated fatty acids. However there is no synthetic system for making two essential fatty acids including linoleic acids (18 carbon atoms and two double bonds) and alpha-linolenic acid (18 carbons with 3 double bonds); thus it is necessary to incorporate these compounds in human diet on a daily basis.
Essential fatty acids or “EFAs” which are polyunsaturated fatty acids are categorised as omega-6 (n—6) and omega-3 (n—3)fatty acids. The body is unable to provide the required enzyme to introduce a double bond at the omega-6 and omega-3 places; although the body may enable conditions for conversion (e.g. one omega-3 to some other omega-3), but it is unable to construct one n—3 from n—6 or from saturated fatty acids.
Essential fatty acids are necessary for mammals in order to supplying compounds responsible for maintaining regular mechanism of the body. For instance, they facilitate balancing the blood pressure and blood lipid proportion; promoting the immune system and blood clotting. Insufficient /imbalanced intake of omega-3 in diet may induce adverse effects on moods and behaviour (including developing aggressive behavior and depression). The main contributory factors to these symptoms are still unclear. Essential fatty acids are abundantly available in oils of nuts; seeds; vegetables (e.g. walnut, flax seeds, chia seeds, pumpkin seeds, grape seeds and canola oil) and fish (e.g. sardines).
According to the recent research conducted on rodents, linoleic acids have some beneficial properties which can suppress/reduce the risk of cancer-related diseases. Results have also confirmed that linoleic acids are able to reduce the body fat in addition to improving muscle tissue and bone density. Further studies are being carried out to ascertain the ability of these functions in human body.
Linoleic acid (LA) is mainly obtainable from some vegetable oils especially grape seed oils which are extracted from the seeds of “vitis vinifera grapes
” ranges. Oils from these plants contain considerable quantities of fatty acids; polyunsaturated (69%), monounsaturated (16%) and saturated (9%) fatty acids. Grape seed oils are nutritionally valuable in terms of high contents of linoleic acids which can supply omega-6 essential fatty acids in the human diet. Oleic acids also account for a relatively noticeable amount in grape seed oils (provide omega-9 monounsaturated fatty acids).
Alpha-linolenic acid (ALA) is classified as polyunsaturated omega-3 fatty acid which is commonly originated from seeds and nuts (including flax seeds with 18 % omega-3, butter nuts, walnuts and pecan nuts); and seafood specially oily fish such as herring, sardines, mackerel, anchovies and trout. The body has the ability to convert alpha-linolenic acid into the “longer chain fatty acids” including eicosapentaenoic acid
(EPA) and docosahexaenoic acid
It has been reported that ALA has some protective characteristics against cardiovascular disease particularly arrhythmia
(irregular heart beat). However it is yet to be analyzed if this beneficial factor is purely due to the presence of ALA or it is in association with those metabolic compounds (EPA and DHA). Fish oil can dramatically contribute to maintaining a healthy system within the human body. For instance, a balanced intake of fish oils is said to be in direct connection with reducing/preventing the possibility of depression, anxiety and bad mood.
Consumption of oily fish or fish-based food products are highly recommended as part of the daily diet in order to achieve optimum nutritional benefits; since the conversion process of ALA to EPA is virtually restricted (due to the competitive actions between linoleic acid and alpha-linolenic acid mainly for the metabolic enzymes). It is generally more efficient to acquire the long chain omega-3 fatty acids from the food intake directly rather than being supplied by the conversion and synthetic mechanism as the resultant absorption inefficiency or imbalanced proportion of n—6 to n—3 may occur in consequence of LA and ALA competition.
Adequate ratio of n—6 to n—3 is crucial with respect to developing cardiac health. Furthermore, the ratio is important as it may contribute to changing the ratio of some hormones and finally modifying the metabolic system in the body. In general, optimum/acceptable proportion of n—6 to n—3 is achievable from the regular and balanced consumption of foods including seeds, nuts, fish and shellfish. In food industry there has been a developing trend towards food fortification with fish oil omega—3 fatty acids including bread, dry pasta, eggs, soft drinks, and some dairy products which are supplemented within permitted amount of n—3 fatty acids.