N 3 PUFAs ratio

Ln recent years, interest increased in the ratio of omega-6 (n-6) to omega-3 (n-3) PUFA, or LA ALA, in part due to the link between inflammation and several lifestyle diseases, such as cardiovascular disease (CVD) and Type LL diabetes. However, whether this ratio is directly associated with an increased risk of inflammatory diseases is unclear. Furthermore, the low conversion of dietary ALA to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (Goyens et al., 2005 Hussein et al., 2005 Pawlosky et al., 2001) means that a lower n-6 n-3 PUFA ratio does not necessarily reflect physiologically important increases in EPA and DLiA (Harris, 2006). Consequently, evaluating absolute dietary intakes of specific n-6 and n-3 PUFAs may be most appropriate, particularly when few human experimental and clinical trial data exist to support the use of an n-6 n-3 PUFA ratio. Nevertheless, when considering the composition of SBO, notably, SBO has a lower n-6 n-3 PUFA ratio than other commonly used vegetable oils, such as corn oil. 

In this study, various high n-3 PUFA triacylglycerols were transesterified with a high n-6 PUFA triacylglycerol to produce structured TAG with desired or within the recommended n-6/n-3 PUFA ratios. A desirable target range of... 

Estimates of current fat intakes are considered to have high contents of saturated and PUFA and a high n-6 to n-3 PUFA ratio (Table 13.15). Recommendations have been made to reduce total fat, saturated fats, and decrease the n-6 to n-3 PUFA ratio from 9/1 to 3/1. More recently, dietary guidelines have been made from various international task forces on the basis of both epidemiological and intervention studies in humans (Table 13.16). They recommend consuming ... 

The traditional p/s ratio and now the n-6/n-3 PUFA ratio may be of little value because they fail to recognize the multiple effects of dietary PUFA and their metabolic interrelationships. In a multivariate system, attempts to describe a ratio of two variables have little meaning and are an inappropriate description of a mixture of fatty acids having a multiplicity of biosynthetic effects. These values should therefore be considered only as possible targets. It should be no longer valid to base dietary recommendations on the attainment of plasma... 

A diet with a high n-6 to n-3 PUFA ratio can cause a high tissue n-6 to n-3 PUFA ratio (i.e. a high AA to EPA ratio), which may promote the production of TXA, leading to increased tendency to thrombosis (Kinsella et al, 1990). Evidence from dietary intervention studies suggests that the production of... 

Fat is a key component in the human diet. Research shows that excessive consumption of saturated fat negatively impacts several biomarkers of health while monounsaturated and n-3 PUFAs are beneficial to human health. Moreover, research shows that imbalanced dietary ratios of n-6 n-3 may lead to various health complications as well as disease progression while increased n-3 levels impart prevention and health promoting effects (Burghardt et al., 2010 Goodstine et al., 2003 Simopoulos, 2002 Wan et al., 2010). The American Heart Association recommends eating fatty fish meals at least twice a week due to their promising health and especially cardiovascular benefits. Here, we review some of the health benefits of n-3 PUFAs, due in part to their anti-inflammatory effects in cancer, cardiovascular diseases (CVDs), obesity, and other metabolic disorders. 

There is also controversy over the importance of MUFA over PUFA from the metabolic viewpoint. Great emphasis is placed on the distinction between the n-3 PUFA and those of the n-6 family. An increased intake of n-3 and a reduced intake of n-6 are recommended in light of the competitive metabolism of both families of fatty acids. As linoleic acid is a n-6 parent, a reduction of its intake favors the n-3/n-6 ratio on the other hand, it is also an essential fatty acid. 

Furthermore, a diet with low contents of FA may be involved in the development of insulin resistance, which suggests that an appropriate dietary intake of n-3 PUFA is considered protective against metabolic syndrome [183]. In addition, diverse psyquiatric impairs (depression, bipolar disorders, schizophrenia, autism) and neurodegenerative diseases such as Alzheimer disease have been associated to decreased blood levels of n-3 HUFA. Besides, there are many examples about the use of pol)nmsaturated FA as drugs. Thus, EPA has shown efficacy as adjunctive treatment, and in some cases as the only treatment in several psyquiatric disorders [184]. It is suggested that the potential of n-3 FA to prevent recurrence and metastasis of mammary cancer when used in adjuvant therapy is associated with a n-6 to n-3 ratio lower than 2 1 [185], On the other hand, fish intake is considered as a protective factor for preventing prostate cancer in addition, in humans low levels of ALA in mammary adipose tissue are associated with an increased risk of breast cancer in women [186]. 

The metabolism of n-3 and n-6 PUFAs is interlinked, as they compete for enzymes and metabolic substrates at all levels. Therefore, relative as well as absolute dietary intake is relevant in the determination of tissue n-3 and n-6 fatty acid levels. The Western diet typically contains high levels of n-6 fatty acids, as these are components of most animal and vegetable fats. Dietary sources of n-3 PUFA are varied. The most plentiful sources are fish, shellfish, and marine products, which contain large amounts of EPA and DHA. Certain plant oils, such as rapeseed (canola), soybean, and perilla contain large amounts of LNA (Crawford Sinclair, 1972 Sinclair, 1975). Although beef and lamb do contain n-3 PUFAs, both the absolute content and the n-3 n-6 ratio of PUFAs within these meats is low. 

Western diets typically contain low levels of n-3 PUFAs (Simopoulos, Leaf, Salem, 2000). Furthermore, relative to the diet of early man, today s diet is not only higher in saturated fats but has an altered ratio of the two major groups of PUFAs. Modern-day humans are, most probably, descendants of coastal-dwelling hunter-gatherers, with a primary diet of fish, shellfish, and plant matter. This omnivorous, and opportunistic, diet was varied and most probably low in saturated fat. The ratio of n-6 to n-3 fatty acids during the early part of human evolution was close to 1, whereas, today, the ratio is 10 1 or more (Eaton, Eaton, Sinclair, Cordain, Mann, 1998 Simopoulos, 1998). Arecent study in Australia (Sinclair, unpublished) indicates that DHA intake is 0.1 % of fat intake, or about 100 mg/d. The recommended intake is 0.5-1% (Simopoulos et al., 2000). Furthermore, recent data from our group (Sinclair, unpubUshed) has shown that reduced DHA levels in neural tissue occur in animals that are maintained on high saturated fat diets similar to that of a Western diet. 

A comparison of FA composition in lean fish flesh from various areas shows similar amounts of total PUFA but variable proportions of individual (n-3) PUFA in them. The pattern of variation seems clear freshwater fish contain less (n-3) PUFA than marine fish and the content of (n-3) PUFA increases with increasing latitude (Dunstan et al., 1999), which can be explained by adjustment of the membrane function to environmental constraints. The (n-3)/(n-6) ratios in the same fish species (barra-mundi) from salt and fresh water were 1.66 + 0.57 and 0.66 + 0.15, respectively, and... 

In conclusion, our results suggest that n-3 PUFA decrease TNF-a production partially through inhibiting the production of the proinflammatory eicosanoids, LTB and TXAj. It has been suggested that diets with an increased ratio of n-3 to n-6 PUFA may provide a condition favorable to effective drug treatment because the current Western diet, with its low n-3/n-6 ratio, may be suboptimal for the effectiveness of drug therapies that require inhibition of proinflammatory cytokines as well as proinflammatory eicosanoids derived from n-6 PUFA (41). By decreasing the proinflammatory eicosanoids and cytokines, EPA or fish oil may have its special value as a food component or supplement for dietary intervention of a series of inflammatory diseases. 

The n-6/n-3 ratios were obtained by dividing total mol% n-6 PUFA by total mol% n-3 PUFA. 

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