Effects of Lignan-rich Diet on Cardiometabolic Risk Factors
Condition: Metabolic Syndrome; Overweight; Central Obesity; Impaired Glucose Tolerance
MeSH terms: Overweight; Metabolic Syndrome; Glucose Intolerance; Obesity, Abdominal
Study type: Interventional

Summary: 
      Diet plays an important role in relation to prevention of type 2 diabetes, cardiovascular
      disease and certain cancers. Studies have shown that diets with high whole-grain content
      could decrease the risk of these lifestyle related diseases and in Sweden the national
      dietary guidelines recommends whole-grain based instead of refined cereal products. It is,
      however, not clear whether whole-grain from wheat and rye share similar protective effects
      since there are large differences in amount and quality of dietary fibre and associated
      bioactive compounds. The aim of this study is to evaluate the impact of a wholegrain diet
      with low- or high lignan content on different cardiometabolic risk factors with the primary
      endpoint being blood glucose levels after 2h oral glucose tolerance test in men with
      metabolic syndrome or sign thereof.
    

Detailed description: 
      The study will be conducted in a randomized, cross-over design (8 wk intervention periods).
      The lignan-rich diet will be based on whole-grain rye products whereas the control diet will
      be based on whole-grain wheat products with some added wheat bran. Both diets will provide
      similar amount of whole grain (g/d) and total dietary fiber content (but dietary fibre
      quality will be different). Although rye has high lignan content, the aim is to further
      increase the lignan intake half-way through the whole grain rye intervention period. This
      will allow us to distinguish the effect of lignans from the effect of whole grain rye as well
      as evaluating potential differences in effects on cardiometabolic risk factors between whole
      grain wheat and whole grain rye intake after 4-week consumption. The study design will also
      allow us to investigate the effects of a putative interaction between microbiome x lignan
      rich diet and its implication of metabolic risk factors.

      Blood samples will be collected by trained nurses at screening, baseline, after 4 weeks and 8
      weeks of first intervention period, after wash-out (8 weeks), and after 4 weeks and 8 weeks
      of the second intervention period.

      At each examination day participants will arrive to the test laboratory for blood samples and
      an oral glucose tolerance test (OGTT) where participants will be given a drink with 75 g of
      glucose to consume within 10 minutes. Blood samples will be taken after 30, 60 and 120
      minutes. Furthermore, participants will be instructed to complete one 3-day weighted food
      record and also to collect 24-h urine and a fecal sample at week 0, 4, 8, 16, 20 and 24.
    

Intervention name(s): Whole-grain rye, high lignan; Whole-grain wheat, low lignan
Intervention type(s): Other; Other
Intervention description(s): Intervention week 1-8: 50 g rolled rye + 50 g puffs + 4 pieces of crisp bread + 70 g pasta. Additionally for intervention week 4-8: 4 lignan capsules per day; Intervention week 1-8: 100 g puffs + 4 pieces of crisp bread + 70 g pasta.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: intervention; lignans; whole-grain