Lack Of Polyunsaturated Fatty Acids Research Articles

Saturated Fats: Time to Assess Their Beneficial Role in a Healthful Diet

Saturated fats are widely seen as undesirable components of a healthy diet, as a result of their illusory association with elevated serum cholesterol. The regulation of serum cholesterol is now better understood and a lack of polyunsaturated fatty acids, rather than an abundance of saturated fatty acids, is responsible. Palmitic acid was shown to incite inflammation at unnaturally high concentrations in tissue culture, but later was found to play an auxiliary role as a precursor to ceramide biosynthesis and possibly in the palmitoylation of membrane receptors involved in the initiation of inflammation. Studies of arthritic inflammation in lab animals showed that dietary saturated fats are anti-inflammatory, whereas polyunsaturated oils are pro-inflammatory. Inflammation plays a role in numerous metabolic diseases, including insulin resistance, fatty liver disease and metabolic syndrome, among others. Fat, as triglycerides in adipose tissue, is an efficient way for living organisms to store energy and reduce the toxicity of other macronutrients. Macronutrients, such as excess carbohydrates and polyunsaturated fatty acids, are converted to saturated and monounsaturated fatty acids for storage as triglycerides in adipose tissue. Fatty acids are released from adipose tissue during fasting and as a result of some metabolic disorders, where elevated levels of nonesterified fatty acids in blood can lead to hepatic lipid accumulation, inflammation and insulin resistance. Although most serum nonesterified fatty acids may be saturated fatty acids, they are not necessarily derived from the diet. This paper will attempt to clarify the role of saturated fatty acids, and palmitic acid in particular, with regard to certain adverse health conditions.

Omega-3 fatty acids-critical for the marine food web and for seabird productivity

Abstract Seabird reproductive success in northern latitudes is often linked with prey abundance, availability, size, or species. Causes are often broadly explained as changes in ocean currents/temperatures, or diets. Few studies trace diets down the food web to primary producers, thus missing what I propose as an underlying cause of seabird colony failure, dietary abundance of essential omega-3 polyunsaturated fatty acids (PUFA). PUFA differ from other nutrients because they are, in part, ligands—critical for reproduction and other physiological processes for the entire marine food web, not just for seabirds. Diatoms are one of the few life forms that can produce PUFA de novo, and a lack of PUFA in zooplankton and fish reduces their abundance and productivity, with consequences up the food web. Since the mid-1980s, historical prey of breeding seabirds has decreased, and frequency of colony failures has increased. In years of failure, prey often had less fat than historically preferred species. Likewise, proportions of alternate species’ PUFA, from published papers, show lower values than in historical prey. Production of PUFA by diatoms is depressed in warmer and more acidic environments, and I hypothesize that these warmer and more acidic seas have affected production of PUFA over the past 3–4 decades. Assuming this is true, I propose that these lower amounts of PUFA have negatively impacted the breeding success of all members of the marine food web, not just seabirds.

Enrichment of polyunsaturated fatty acids in black soldier fly larvae (Hermetia illucens) fortified with squid liver oil

Black soldier fly larvae (BSFL;Hermetia illucens) are known as an alternative feed for livestock, but their lack of polyunsaturated fatty acids (such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) makes it less valuable. To overcome these problems, BSFL substrate (chicken feed) was fortified with squid liver oil (SLO) at five different concentrations (0, 2.5, 5, 10, and 20%). The growth rate, feed conversion, and nutritional content of BSFL were evaluated at day 15 of rearing. Of the five concentrations, SLO 5% showed the highest growth increase (25.82-fold) among the other treatments (20.63-22.98-fold;P<0.05). The fortification of SLO 5% did not result in differences in survival and feed conversion of larvae compared to larvae fed the control substrate. By rearing BSFL in a substrate containing SLO 5%, the lipid content of the larvae was 32% higher than that of larvae fed the control substrate (P<0.05). The accumulation of lipids was faster in the substrate containing SLO 5% (33.20% for 8 days) than in the control substrate (24.36% for 15 days). The control group of BSFL contained no DHA or EPA, but after rearing on the SLO 5% fortified substrate, the larvae contained DHA at an average level of 2.99 g/100 g lipid and EPA was 2.68 g/100 g lipid. Harvested larvae from SLO 5% treatment was within safe levels of Pb, Cd, As, and Hg (840, 370, 860, and 26.7 μg/kg, respectively), under the EU threshold for animal feed. Based on our results, it concluded that BSFL enriched with PUFAs, DHA and EPA can be considered as important nutritional components of animal feed without excessive heavy metals accumulation by feeding SLO in an appropriate amount.

HYGIENIC ASSESSMENT OF NUTRITION STATUS OF THE POPULATION OF THE GERONTOLOGICAL GROUP

Among many environmental factors nutrition is paramount, permanently and exclusively affecting in multidisciplinary mode on the biological and social essence of the human body. Therefore, this article describes the results of the actual supply of people aged of 60-89 years taking into account their eating habits associated with age-related changes in the gastrointestinal tract and metabolism. The study involved 611 respondents aged of 60-89 years, including men (23.9%) and women - 76.1%, living in Astana, the average age accounts of 73 ± 0.41years. The actual food was studied by frequency and a 24-hour simulation, recommended by the WHO for epidemiological studies. In assessing the adequacy of the supply of the reference values there were taken norms of physiological requirements in energy and nutrients for the population of gerontological groups of the Republic of Kazakhstan, as well as the norms of consumption of micronutrients on a scale of FAO / WHO. The study of the actual nutrition of the category of persons of Astana showed the diet of elderly people to be consisted of foods containing mostly protein and animal fats and digestible carbohydrates, while two latters were characterized by an excess of saturated fatty acids, the lack of polyunsaturated fatty acids, a high level of simple consumption carbohydrates from refined foods such as sugar, refined cereals, flour and poly- micronutrient failure of the nutrition on vitamins (deficiency of vitamin D, a, B1, E, C, biotin, folic and pantothenic acid) and minerals (calcium deficiency, potassium).

Lack of Dietary Polyunsaturated Fatty Acids Causes Synapse Dysfunction in the Drosophila Visual System.

Polyunsaturated fatty acids (PUFAs) are essential nutrients for animals and necessary for the normal functioning of the nervous system. A lack of PUFAs can result from the consumption of a deficient diet or genetic factors, which impact PUFA uptake and metabolism. Both can cause synaptic dysfunction, which is associated with numerous disorders. However, there is a knowledge gap linking these neuronal dysfunctions and their underlying molecular mechanisms. Because of its genetic manipulability and its easy, fast, and cheap breeding, Drosophila melanogaster has emerged as an excellent model organism for genetic screens, helping to identify the genetic bases of such events. As a first step towards the understanding of PUFA implications in Drosophila synaptic physiology we designed a breeding medium containing only very low amounts of PUFAs. We then used the fly’s visual system, a well-established model for studying signal transmission and neurological disorders, to measure the effects of a PUFA deficiency on synaptic function. Using both visual performance and eye electrophysiology, we found that PUFA deficiency strongly affected synaptic transmission in the fly’s visual system. These defects were rescued by diets containing omega-3 or omega-6 PUFAs alone or in combination. In summary, manipulating PUFA contents in the fly’s diet was powerful to investigate the role of these nutrients on the fly´s visual synaptic function. This study aims at showing how the first visual synapse of Drosophila can serve as a simple model to study the effects of PUFAs on synapse function. A similar approach could be further used to screen for genetic factors underlying the molecular mechanisms of synaptic dysfunctions associated with altered PUFA levels.

Altered serum mono- and polyunsaturated fatty acid levels in adults with ADHD

Other than in children diagnosed with attention deficit hyperactivity disorder (ADHD), the connection between ADHD and lipids has not been sufficiently investigated so far in adults. Blood serum lipoproteins and fatty acids (FA) composition were measured and analyzed by colorimetry and gaschromatography in eight male and seven female adults diagnosed with ADHD as well as in 15 age- and gender-matched healthy control subjects. In ADHD patients, polyunsaturated FAs [docosahexaenoic, arachidonic and dihomogammalinolenic acid (p = 0.048; 0.003; 0.012)] showed lower concentrations, while monounsaturated acids (palmitoleic and oleic acid) as well as total and LDL cholesterol showed higher concentrations (p = 0.011; 0.005). ADHD scores positively correlated with palmitoleic (R = -0.56; p = 0.032), stearic (R = 0.53; p = 0.044), eicosapentaenoic (R = 0.62; p = 0.014), docosahexaenoic (R = 0.51; p = 0.050), gammalinolenic (R = 0.62; p = 0.018) and alphalinolenic acid (R = 0.56; p = 0.031) concentration. Even though the total and LDL cholesterol concentrations in blood serum were significantly higher among the ADHD patients than in controls, none of the ADHD symptom scores were significantly associated with any of the lipoproteine measures. We could demonstrate that a lack of polyunsaturated FAs in blood serum of subjects with ADHD persists into adulthood. Furthermore, we could show that adult ADHD symptomatology positively correlates with elevated levels of saturated stearic and monounsaturated FAs.

Fatty acid composition of liver lipids during ontogeny of the chick embryo: effect of a single dose of triiodothyronine.

Fatty acid composition of chick liver was determined throughout embryo development. Fourteen, seventeen and twenty day old chick embryos as well as newborn chicks were studied. Chromatograms show that in all cases the same fatty acids were presented, even when lipid fractions such as phospholipids, cholesterol and triacylglycerol were studied separately. The lack of poly-unsaturated fatty acids is in contrast with the results obtained in previous investigations on rats. A slight increase in the unsaturated/saturated fatty acid ratio as the embryo grew older was observed. The effect of a single dose of 3-3'-5-Triiodothyronine (T3) on composition of fatty acids throughout the embryonary period was also studied. The hormone only affects fatty acid levels in the 20th and 21st days of incubation.

Saccharomyces cerevisiae strain expressing a plant fatty acid desaturase produces polyunsaturated fatty acids and is susceptible to oxidative stress induced by lipid peroxidation

Although oxygen is essential for aerobic organisms, it also forms potentially harmful reactive oxygen species. For its simplicity, easy manipulation, and cultivation conditions, yeast is used as an attractive model in oxidative stress research. However, lack of polyunsaturated fatty acids in yeast membranes makes yeast unsuitable for research in the field of lipid peroxidation. Therefore, we have constructed a yeast strain expressing a Δ12 desaturase gene from the tropical rubber tree, Hevea brasiliensis. This yeast strain expresses the heterologous desaturase in an active form and, consequently, produces Δ9/Δ12 polyunsaturated fatty acids under inducing conditions. The functional expression of the heterologous desaturase did not affect cellular morphology or growth, indicating no general adverse effect on cellular physiology. However, the presence of polyunsaturated fatty acids changed the yeast's sensitivity to oxidative stress induced by addition of paraquat, tert-butylhydroperoxide, and hydrogen peroxide. This difference in sensitivity to the latter was followed by the formation of 4-hydroxy-2-nonenal, one of the end products of linoleic fatty acid peroxidation, which is known to play a role in cell growth control and signaling. Here we show that this yeast strain conditionally expressing the Δ12 desaturase gene provides a novel and well-defined eukaryotic model in lipid peroxidation research. Its potential to investigate the molecular basis of responses to oxidative stress, in particular the involvement of reactive aldehydes derived from fatty acid peroxidation, especially 4-hydroxy-2-nonenal, will be addressed.

The role of polyunsaturated fatty acids in the expression of torpor by mammals: a review

Heterothermic mammals increase the proportion of polyunsaturated fatty acids (PUFA) in their body fats prior to entering torpor. Because PUFA have low melting points, it is thought that they play an important role in maintaining the fluidity of depot fats and membrane phospholipids at low body temperatures. However, PUFA are more prone to autoxidation when exposed to reactive oxygen species (ROS) during torpor and during the periodic arousals that characterize hibernation. A lack of PUFA or an excess of PUFA may constrain the use of torpor by heterothermic mammals. We performed a mixed model meta-analysis of 17 controlled-feeding studies to test the effect of dietary PUFA on the depth and expression of torpor by daily heterotherms and hibernators. We also reviewed the literature on the PUFA content of the diet and depot fats of heterothermic mammals to address two principal topics: (1) Do low dietary levels of PUFA reduce the expression of torpor under laboratory conditions and, if so, are free-ranging animals constrained by a lack of PUFA? (2) Do high dietary levels of PUFA result in a reduction in the use, depth, and duration of torpor and, if so, do free-ranging animals seek to optimize rather than maximize PUFA intake? Low-PUFA diets consistently increase the lower setpoint for body temperature and minimum metabolic rate for both hibernators and daily heterotherms. Above the lower setpoint, low-PUFA diets usually increase body temperature and metabolic rate and decrease the duration of torpor bouts and this effect is similar for hibernators and daily heterotherms. Free-ranging rodent hibernators have dietary PUFA intakes that are far higher than those of the low-PUFA diets offered in controlled-feeding experiments, so these hibernators may never experience the constraints associated with a lack of PUFA. Diets of free-ranging insectivorous bats and echidnas have PUFA levels that are less than half as high as those offered in experimental low-PUFA diets, yet they exhibit deep and extended bouts of torpor. We argue that alternate mechanisms exist for maintaining the fluidity of body fats and that high-PUFA intake may not be a prerequisite for deep and extended bouts of torpor. Four studies indicate that animals that were fed high-PUFA diets are reluctant to enter torpor and show shallower and shorter torpor bouts. Although authors attribute this response to autoxidation, these animals did not have a higher PUFA content in their depot fats than animals where PUFA was shown to enhance torpor. We suggest that these contradictory results indicate inter-specific or inter-individual variation in the ability to control ROS and limit autoxidation of PUFA. High dietary levels of PUFA will constrain the expression of torpor only when the oxidative challenge exceeds the capacity of the antioxidant defence system. Studies of diet selection indicate that insectivorous species with low dietary PUFA levels seek to maximize PUFA intake. However, herbivorous species that have access to plants and plant parts of high-PUFA content do not appear to maximize PUFA intake. These data suggest that animals attempt to optimize rather than maximize PUFA intake. The effect of PUFA should be viewed in the light of a cost–benefit trade-off, where the benefit of high-PUFA intake is an easier access to low body temperatures and the cost is increased risk of autoxidation.

Dietary Lipid and Iron Status Modulate Lipid Peroxidation in Rats with Induced Adjuvant Arthritis

We studied the effect of dietary lipids on iron metabolism and lipid peroxidation during induced adjuvant arthritis and/or iron overload in rats. We compared a control diet containing corn oil and rapeseed oil with a diet devoid of polyunsaturated fatty acids containing only tripalmitin as lipids. Four subgroups of rats were used with each diet: without further treatment, with induction of adjuvant arthritis, with iron overload, and with induction of adjuvant arthritis and iron overload. The profile of fatty acids present in plasma and in microsomes changed in rats fed the tripalmitin diet. The level of tetra- and pentaunsaturated fatty acids was reduced, and the level of monounsaturated fatty acids and iron stores was increased with respect to control rats. Thus, ingestion of a tripalmitin diet reduced the substrate for lipid peroxidation, as shown by the decrease in thiobarbituric acid-reactive substances in plasma and conjugated dienes in hepatic microsomal fraction. Adjuvant arthritis and iron overload had a synergistic effect on lipid peroxidation and iron storage in liver. Further, in the hepatic microsomal fraction, tripalmitin reduced the levels of cytochrome P-450, and arthritis reduced the levels of cytochrome P-450 and Ca2+ sequestration. Our results suggest that rats fed tripalmitin showed a reduction of lipid peroxidation induced by inflammation or by iron overload, because of the lack of polyunsaturated fatty acids in the diet, although tripalmitin usually increases the iron stores in the body and causes hepatic alterations.

Low unsaturation level of thylakoid membrane lipids limits turnover of the D1 protein of photosystem II at high irradiance

Turnover of the D1 protein of photosystem II (PSII) was studied in mutants of Synechocystis sp. PCC 6803 defective in the desaturation of thylakoid membrane lipids. The lack of polyunsaturated fatty acids from membranes made PSII extremely susceptible to photoinhibition and caused a significant reduction in the D1 protein content of the thylakoid membranes at high irradiances. These results may be attributed to an impaired function in the protein synthesis machinery, most probably at the translational or posttranslational level.

Unsaturated fatty acid composition and biosynthesis in Oscillatoria limnetica and other cyanobacteria

A number of cyanobacteria showing a high degree of adaptation to life under reduced oxygen tensions as witnessed by their potency of facultative anoxygenic CO2 photoassimilation with sulfide as electron donor were found to lack polyunsaturated fatty acids in their lipids. Lack of polyunsaturated fatty acids was found in representatives of different taxonomic groups. One of the strains lacking polyenoic acids was Oscillatoria limnetica, which can alternatively grow acrobically or anaerobically with sulfide as electron donor. This organism was found to synthesize monounsaturated fatty acids by desaturation of their saturated counterparts, in the presence as well as in the absence of molecular oxygen.