Fatty Acid Desaturase Gene Locus Interactions With Diet (FADSDIET2)
Condition: Fatty Acids; Genetics
Study type: Interventional

Summary: 
      Interactions between genes and environment, are likely to be crucial in the development of
      the common diseases such as type 2 diabetes. Recently, the investigators have obtained data
      that genotypes of genes encoding for fatty acid desaturases 1 and 2 (FADS1 and FADS2) are the
      strongest genes in a genome-wide analysis regulating serum fatty acid profile.The aim of this
      study is to test if subjects with different genotypes of the FADS2 gene respond differently
      to a diet supplemented with linoleic acid or alpha-linolenic acid (substrates for FADS2). The
      study hypothesizes that subjects will be more sensitive to the dietary modifications
      according to their genotype leading to more robust differences in serum FA profile, tissue
      inflammation and serum lipids.
    

Detailed description: 
      Lean and overweight subjects (Body mass index: BMI >20kg/m2 <32kg/m2 ) with CC and TT
      genotypes of FADS1 single nucleotide polymorphism (SNP) from the METabolic Syndrome in Men
      (METSIM) study, in which currently >10000 men are included from the population living in
      Kuopio, will be recruited. Seventy subjects with CC genotype will be selected after matching
      with the 70 subjects with the TT genotype for age and BMI.

      After a 4-week run-in period, the subjects within each genotype group will be randomly
      assigned into two study groups according to medians of BMI, age and fasting plasma glucose
      concentration: in one group the diet will be enriched with linoleic acid (LA, sunflower oil)
      and in the other group with alpha-linolenic acid (ALA, camelina oil). The intervention will
      last for 8 weeks.

      The sample size calculation is based on the observed change in arachidonic acid (AA) in the
      cholesterol esthers fraction between CC and TT genotypes (12.14 vs. 4.20 mol%, respectively)
      after the diet enriched in LA from preliminary data. Considering a β=0.80 and an α=0.025
      instead of only 0.05 to account for the fact that we now have two dietary interventions
      instead of one, 31 participants in each study group would need to be included. Assuming
      around 15% of dropouts in this trial, a final sample size of 35 for each group is required.

      The study diet will be isocaloric following the habitual diet of the participants with a
      supplement of 30-50 ml (25-45 g) sunflower or camelina oil daily depending on body weight.
      The dose of each oil is not known to cause any side effects or adverse events and even higher
      doses have been safe.

      Participants will record their daily oil consumption and 4-day food records will be collected
      at the beginning and two times during the intervention period to measure daily intake of
      macronutrients and specifically different fatty acids.
    

Intervention name(s): LA; ALA
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): The source of linoleic acid (LA) will be sunflower oil (62-63 % LA). The study diets will be isocaloric. The allowed weight change during the study is ± 2-3 %. The amount of supplementary oil will be calculated individually based on the calculated energy expenditure and adjusted, if necessary, during the study based on body weight measurements.; The source of alpha-linolenic acid (ALA) will be camelina sativa oil (30-35 % ALA). The study diets will be isocaloric. The allowed weight change during the study is ± 2-3 %. The amount of supplementary oil will be calculated individually based on the calculated energy expenditure and adjusted, if necessary, during the study based on body weight measurements.
Other intervention name(s): sunflower oil; camelina oil
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: Nutrigenetics