The bioavailability of the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can be influenced by a number of factors including chemical structure of the fatty acid binding form and the food matrix with which the fatty acids are consumed. In addition to this, there is evidence from animals that the lipid metabolism follows a circadian pattern, although this has yet to be investigated in humans.

The supplement is produced as a soft gelatine capsule containing fish oil based high concentrate omega-3 fatty acids designed to improve bio availability via a self-emulsifying drug delivery system (SMEDDS). The in-situ formation of an emulsion occurs spontaneously when the capsule erupts in vivo and the SMEDDS solution comes in contact with the gastro-intestinal contents. The size of the microdroplets that are formed is in the lower micrometer range, the advantage of which is a much larger combined surface area compared to drops of oil which results in better access for pancreatic lipases. The resulting free fatty acids may then readily be absorbed during its passage through the upper small intestine resulting in an effective absorption of the oil.

Therefore duel objectives of this study are to determine the bioavailability in healthy middle aged adults of two formulations of fish oil taken at bed time using SMEDDS and to evaluate the diurnal variation in background plasma fatty acids.

All study visits will take place on the 4th floor of the Northumberland Building, Northumbria University within a suite of facilities comprising the Nutrition Kitchen, Sleep Centre, Clinical space and the waiting room of the Brain, Performance and Nutrition Research Centre. Participants will attend the lab on five separate occasions. The first visit will be a screening/introductory visit. The Introductory visit to the laboratory will comprise: providing each participant with a 'participant information sheet', briefing them on the requirements of the study and signing of the informed consent form and completion of the Case Report Form (CRF; including self-reported health screening and collection of demographic data). Participants will then attend the lab for four study visits which will be separated by at least 6 days, each of which will be identical except for the treatment that they will consume. On each of the study visits participants will arrive at the lab at 19:30 having consumed nothing but water for at least 2 hours prior to their arrival where their continued eligibility will be assessed. A cannula will then be inserted into a vein in the arm of the non-dominant hand. The first blood sample will be collected immediately prior to their evening meal which will be served at 20:00 and will be followed by a rest period. At 22:00 participants will consume their evening's treatment. Lights out will be at 22:30. Blood samples will be drawn every 2 hours through the night at 00:00, 02:00 and 04:00. Participants will be woken up at 06:00 and a blood sample will be taken straight away. Blood samples will continue to be collected every two hours until 22:00 when the cannula will be removed. Meals will be provided at 07:00, 12:00, 16:00 and 20:00, with the evening meal being exactly the same as the previous evening. Participants will have ad libitum access to water throughout the study visit. They will also be allowed to consume tea and coffee throughout the day however the content and the timing of the hot drinks they consume on the first study visit will be replicated for the subsequent visits. Similarly, if they do not eat all of the meals that are provided in their entirety, this will be recorded and replicated for the subsequent visits. In between meals and blood samples participants will be required to remain within the facilities where they will be allowed to read, write, watch television or listen to music.