Docosapentaenoic acid : its metabolism and effect on lipogenic gene expression

This thesis found that the omega-3 fatty acid, docosapentaenoic acid (DPA) down-regulates the expression levels of key lipogenic genes and proteins in vitro. In vivo studies with labelled DPA showed that, like docosahexaenoic acid, DPA is more conserved from oxidation compared with eicosapentaenoic acid.<br /

What is the most effective way of increasing the bioavailability of dietary long chain omega-3 fatty acids-daily vs. weekly administration of fish oil?

The recommendations on the intake of long chain omega-3 polyunsaturated fatty acids (n-3 LC-PUFA) vary from eating oily fish (&quot;once to twice per week&quot;) to consuming specified daily amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (&quot;250-500 mg per day&quot;). It is not known if there is a difference in the uptake/bioavailability between regular daily consumption of supplementsvs. consuming fish once or twice per week. In this study, the bioavailability of a daily dose of n-3 LC-PUFA (Constant treatment), representing supplements, vs. a large weekly dose of n-3 LC-PUFA (Spike treatment), representing consuming once or twice per week, was assessed. Six-week old healthy male Sprague-Dawley rats were fed either a Constant treatment, a Spike treatment or Control treatment (no n-3 LC-PUFA), for six weeks. The whole body, tissues and faeces were analysed for fatty acid content. The results showed that the major metabolic fate of the n-3 LC-PUFA (EPA+docosapentaenoic acid (DPA) + DHA) was towards catabolism (&beta;-oxidation) accounting for over 70% of total dietary intake, whereas deposition accounted less than 25% of total dietary intake. It was found that significantly more n-3 LC-PUFA were &beta;-oxidised when originating from the Constant treatment (84% of dose), compared with the Spike treatment (75% of dose). Conversely, it was found that significantly more n-3 LC-PUFA were deposited when originating from the Spike treatment (23% of dose), than from the Constant treatment (15% of dose). These unexpected findings show that a large dose of n-3 LC-PUFA once per week is more effective in increasing whole body n-3 LC-PUFA content in rats compared with a smaller dose delivered daily

PO-265 Acute whole-body vibration increases energy expenditure and skeletal muscle microvascular perfusion

Objective Insulin resistance and cardiometabolic disease are associated with decreased muscle microvascular perfusion which impairs nutrient delivery to the muscle.&nbsp; Impaired glucose and insulin delivery contributes to lower glucose uptake into the skeletal muscle. Exercise increases muscle microvascular perfusion, however, cardiometabolic disease patients are not always willing or able to undertake regular exercise. Objective: Whole-body vibration (WBV) has previously been shown to increase energy expenditure and limb bulk blood flow, however whether WBV increases skeletal muscle microvascular perfusion is not known.&nbsp;&nbsp; Methods Methods: Eleven healthy participants (5 males, 6 females; Age: 33 ± 1.9 years) stood on a WBV platform (Galileo Sport, Novotec Medical GmbH, Pforzheim, Germany) for 3 min at 12.5 Hz which was compared to standing without vibration.&nbsp; Thigh muscle (vastus lateralis) microvascular perfusion was assessed by contrast-enhanced ultrasound (iU22, Philips Medical, North Ryde, NSW, Australia) by infusing Definity® microbubbles (Lantheus Medical Imaging, N. Billeruca, USA) intravenously and measured for 3 min following WBV.&nbsp; Oxygen consumption (Metamax, Cortex Biophysik GmbH, Leipzig, Germany) was measured while standing prior to WBV and during the third minute of WBV. Results Results: Compared with standing without vibration, 3 min of WBV more than doubled muscle microvascular perfusion (0.73 ± 0.17 vs 2.87 ± 0.81 AI/sec, p&lt;0.05) which remained elevated above baseline for 3 min after cessation of WBV. Oxygen consumption modestly but significantly increased while undergoing WBV (282 ± 0.013 vs 419 ± 0.023 mL/min, p&lt;0.05). Conclusions Conclusion: This is the first study to show that WBV significantly increases muscle microvascular perfusion in healthy adults. &nbsp;We are currently undertaking studies to determine if this WBV may be of benefit in populations with impaired microvascular perfusion, such as type 2 diabetes, for improving cardiometabolic health. &nbsp

Mussels as a dietary source of omega-3 fatty acids

Numerous United Kingdom and European Union expert panels recommend that the general adult population consumes ~250mg of EPA+DHA per day through the consumption of 1 portion of oily fish per week. Of particular importance are the long chain omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), which are only found in appreciable amounts in marine organisms. Increasing oily fish consumption conflicts with sustaining fisheries and so alternative dietary sources of EPA+DHA must be explored. Mussels are high in omega-3 PUFAs and are a good source of essential amino acids. Therefore, the present study aimed to investigate the impact of introducing mussels as a protein source in the lunchtime meal 3 times per week for 2 weeks on omega-3 status in free-living participants. Following an initial 2-week monitoring period, 12 participants (8 male, 4 female) attended the nutrition laboratory 3 times per week for two weeks. Each participant received a personalised lunch constituting one-third of their typical daily calorie consumption with ~20% of the calories supplied as cooked mussels. A portion of cooked mussels from each feeding occasion was tested for total omega-3 content. The mean ± SD mussel EPA+DHA content was 518.9 ± 155.7mg/100g cooked weight meaning that each participant received on average 709.2 ± 252.6mg of EPA+DHA per meal or 304.0 ± 108.2mg of EPA+DHA per day. Blood spot analysis revealed a significant increase in the omega-3 index (week 1 = 4.27 ± 0.81; week 4 = 5.07 ± 1.00) and whole blood EPA content during the study (%EPA week 1 = 0.70 ± 0.0.35; %EPA week4 = 0.98 ± 0.35). Consuming mussels 3 times per week for two weeks as the protein source in a personalised lunchtime meal is sufficient to moderately improve the omega-3 index and whole blood DHA+EPA content in young healthy adults

Micronutrient supplement use and diet quality in university students

Many national and international public health organisations recommend achieving nutrient adequacy through consumption of a wide variety of nutritious foods. Despite this, dietary supplement sales continue to increase. Understanding the characteristics of micronutrient supplement users and the relationship with diet quality can help develop effective public health interventions to reduce unnecessary consumption of vitamin and mineral supplements. Participants (n = 1306) were a convenience sample of students studying first year food and nutrition. Data was collected via a Food and Diet Questionnaire (FDQ) and a Food Frequency Questionnaire (FFQ). Supplement users were defined as participants who indicated consuming any listed supplement as frequently as once a month or more. Diet quality was assessed using a Dietary Guideline Index (DGI) score. Prevalence of supplement use was high in this study population with 56% of participants reporting supplement use; the most popular supplements consumed were multivitamins (28%) and vitamin C (28%). A higher DGI score was significantly associated with an increased likelihood of supplement use (mean: 105 &plusmn; 18 vs. 109 &plusmn; 17, p = 0.001). Micronutrient supplement use was associated with a higher DGI score, suggesting that supplements are more likely to be used by those who are less likely to require them

Fish oil diet associated with acute reperfusion related hemorrhage, and with reduced stroke-related sickness behaviors and motor impairment

Ischemic stroke is associated with motor impairment and increased incidence of affective disorders such as anxiety/clinical depression. In non-stroke populations, successful management of such disorders and symptoms has been reported following diet supplementation with long chain omega-3-polyunsaturated-fatty-acids (PUFAs). However, the potential protective effects of PUFA supplementation on affective behaviors after experimentally induced stroke and sham surgery have not been examined previously. This study investigated the behavioral effects of PUFA supplementation over a 6-week period following either middle cerebral artery occlusion or sham surgery in the hooded-Wistar rat. The PUFA diet supplied during the acclimation period prior to surgery was found to be associated with an increased risk of acute hemorrhage following the reperfusion component of the surgery. In surviving animals, PUFA supplementation did not influence infarct size as determined 6&thinsp;weeks after surgery, but did decrease omega-6-fatty-acid levels, moderate sickness behaviors, acute motor impairment, and longer-term locomotor hyperactivity and depression/anxiety-like behavior

Rapid development of non-alcoholic steatohepatitis in Psammomys obesus (Israeli sand rat)

Background and Aims: A major impediment to establishing new treatments for non-alcoholic steatohepatitis is the lack of suitable animal models that accurately mimic the biochemical and metabolic characteristics of the disease. The aim of this study was to explore a unique polygenic animal model of metabolic disease as a model of non-alcoholic steatohepatitis by determining the effects of 2% dietary cholesterol supplementation on metabolic and liver endpoints in Psammomys obesus (Israeli sand rat). Methods: P. obesus were provided ad libitum access to either a standard rodent diet (20% kcal/fat) or a standard rodent diet supplemented with 2% cholesterol (w/w) for 4 weeks. Histological sections of liver from animals on both diets were examined for key features of non-alcoholic steatohepatitis. The expression levels of key genes involved in hepatic lipid metabolism were measured by real-time PCR. Results: P. obesus fed a cholesterol-supplemented diet exhibited profound hepatomegaly and steatosis, and higher plasma transaminase levels. Histological analysis identified extensive steatosis, inflammation, hepatocyte injury and fibrosis. Hepatic gene expression profiling revealed decreased expression of genes involved in delivery and uptake of lipids, and fatty acid and triglyceride synthesis, and increased expression of genes involved in very low density lipoprotein cholesterol synthesis, triglyceride and cholesterol export. Conclusions: P. obesus rapidly develop non-alcoholic steatohepatitis when fed a cholesterol-supplemented diet that appears to be histologically and mechanistically similar to patients. © 2014 Spolding et al

Farmed Mussels: A Nutritive Protein Source, Rich in Omega-3 Fatty Acids, with a Low Environmental Footprint

OThe world’s ever-growing population presents a major challenge in providing sustainable food options and in reducing pressures on the Earth’s agricultural land and freshwater resources. Current estimates suggest that agriculture contributes ~30% of global greenhouse gas (GHG) emissions. Additionally, there is an increased demand for animal protein, the production of which is particularly polluting. Therefore, the climate-disrupting potential of feeding the planet is likely to substantially worsen in the future. Due to the nutritional value of animal-based protein, it is not a simple solution to recommend a wholesale reduction in production/consumption of animal proteins. Rather, employing strategies which result in the production of low carbon animal protein may be part of the solution to reduce the GHGs associated with our diets without compromising diet quality. We suggest that farmed mussels may present a partial solution to this dilemma. Mussel production has a relatively low GHG production and does not put undue pressure on land or fresh water supplies. By drawing comparisons to other protein sources using the Australian Food and Nutrient Database and other published data, we demonstrate that they are a sustainable source of high-quality protein, long-chain omega-3 fatty acids, phytosterols, and other key micronutrients such as B-12 and iron. The aim of this review is to summarise the current knowledge on the health benefits and potential risks of increasing the consumption of farmed mussels