Influence of the Background Diet on Metabolism of Land-based n-3 PUFA
Condition: Endogenous Conversion of Alpha Linolenic Acid
Study type: Interventional

Summary: 
      KoALA study - assessment of the influence of the background diet on the metabolism and the
      bioavailability of plant n-3 PUFA from linseed oil.

      In particular, the study design focusses on the impact of variations in the background diet
      as confounding factor (e.g. variations in concurrently intake of linoleic acid (n-6)).
      Further, the influence of a regular intake of milk fat, in particular from free-grazing
      ruminants, on n-3 PUFA metabolism will be investigated.
    

Detailed description: 
      The KoALA study focuses on the impact of variations in the background diet as a confounding
      factor. The intake of linoleic acid (LA, C18:2 n-6) has been suggested to diminish the
      metabolism of α-linolenic acid (ALA, C18:3 n-3) to eicosapentaenoic acid (EPA, C20:5 n-3) and
      docosahexaenoic acid (DHA, 22:6 n-3).

      In this context, the proposed study will be conducted to evaluate the influence of the
      background diet, in particular the impact of the simultaneous intake of LA on the conversion
      of ALA into their long-chain (LC) metabolites, the incorporation of n-3 LC-PUFA in human
      tissues and their metabolism into eicosanoids and docosanoids. Further, the influence of a
      regular intake of milk fat, in particular from free-grazing ruminants, on n-3 PUFA metabolism
      will be investigated, because short- and middle-chain fatty acids as well as the
      branched-chain fatty acids in milk fat may influence the conversion of ALA into n-3 LC-PUFA
      (hypothesis).

      Thus, validated nutrition concepts for increasing n-3 LC-PUFA status from plant sources will
      be developed to ensure an adequate intake of n-3 PUFA according to the guidelines of
      nutritional societies and as a contribution to the prevention of cardiovascular diseases.
    

Intervention name(s): linseed oil
Intervention type(s): Dietary Supplement
Intervention description(s): linseed oil and defined background diet
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Blood samples will be taken at the beginning and regularly every four weeks during the 12-weeks intervention period. For all groups, the consumption of additional n-3 PUFA sources is not permitted during the entire intervention period. The study intervention will consist of a daily dose of linseed oil (LO, 10 En%) and prepared daily menu plans determining the background diet, except for the control group D. The fat composition of the developed daily menu plans (fat content 20 En%) will differ between the groups A to C. For groups A to C, the daily menu plans will ensure an adequate intake of energy and nutrients according to the guidelines of the German Society of Nutrition. Group D serves as control because in this group the background diet is not fixed by menu plans. Participants of group D must follow their normal dietary habits, i.e. a typical Western diet (LA intake is about 15 g/d (5-7 En%) / SFA intake ranges from 10 to 15 En%).
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: alpha linolenic acid, linseed oil, eicosapentaenoic acid, docosahexaenoic acid