Milk and Soured Milk (filmjölk) Intervention on Oxidative Stress and Inflammation
Condition: Oxidative Stress; Inflammation
MeSH terms: Inflammation
Study type: Interventional

Summary: 
      This study evaluates a high intake of milk compared with a high intake of soured milk
      (Swedish filmjölk) on markers of oxidative stress and inflammation in a randomized crossover
      intervention study.
    

Detailed description: 
      A diet rich in antioxidants reduces oxidative stress and inflammation and could potentially
      improve health and lower the rate of hip fracture. Milk and dairy are also promoted as part
      of a healthy diet since they contain 18 of 22 essential nutrients including calcium,
      phosphorous, and vitamin D and have been suggested to be associated with lower risk of
      cardiovascular disease, especially stroke, type 2 diabetes, and cancer. Meta-analyses of milk
      and dairy on fracture and mortality risk in cohort studies are, however, inconclusive and
      show significant heterogeneity between studies. Small intakes may have beneficial effects in
      comparison to null intake whereas higher intakes may have other effects and non-linear
      relationships are rarely examined. Frequently, different milk products are considered as one
      entity in cohort studies. The investigators recently showed that different milk products
      might have differential effects on disease. A high long-term milk intake was associated with
      an increased risk of mortality (total, cardiovascular, and cancer mortality) and hip
      fracture, especially among women, whereas a high long-term intake of fermented milk (soured
      milk and yogurt or cheese) was associated with a lower risk of mortality and fracture among
      women. Similar results have been presented for total mortality (Northern Sweden) and humeral
      fractures (South-Eastern Australia).

      Intake of milk and fermented milk is of tradition high in Sweden. The prevalence of lactase
      persistence is high (around 95%). The range in milk intake from non- and low-consumers to
      high consumers makes Sweden an appropriate setting for epidemiological and interventional
      studies.

      A common potential mechanism for intake of fruits, vegetables, and different dairy products
      on risk of disease is their influence on inflammation and oxidative stress. Chronic low-grade
      inflammation and age-related increase of oxidative stress are suggested pathogenic mechanisms
      of premature ageing and many diseases including cardiovascular disease, cancer, accelerated
      bone loss (leading to osteoporosis), and age-related reduction of muscle strength and mass
      (sarcopenia) with potential impacts on risk of falling and fracture. The lower risk of
      fractures with a high intake of fermented milk products observed may be due to potential
      probiotic, antioxidative, and anti-inflammatory effects and effects on gut microbiota. A high
      intake of milk was not only associated with risk of mortality and fractures but also with
      increased concentrations of inflammation and oxidative stress markers. An inverse association
      was seen for intake of soured milk and yogurt [Michaëlsson, 2014]. Fermented milk products
      with probiotics have been shown to reduce the levels of inflammation markers, other studies
      have been small to show conclusive effects and results may also be dependent on the probiotic
      strain. A head-to-head comparison of the effect of regular milk and soured milk (or yogurt)
      on markers of inflammation and oxidative stress in a randomized intervention study is
      warranted. The randomized crossover intervention study will be performed among both men and
      women.

      The aim of the study is to examine the potentially different short-term effects of milk and
      sour milk on markers of oxidative stress and inflammation in a randomized cross-over trial.
      The research questions are:

        1. In a randomized cross-over trial, what is the effect of a daily intake of at least 500
           ml of Swedish milk compared with an intake of at least 500 ml Swedish soured milk
           (filmjölk) during 3 weeks on markers of oxidative stress and inflammation?

        2. What are the effects of these milk products on a large number of proteins related with
           inflammation and ageing diseases, assessed with large-scale proteomic analysis?

        3. What are the effects of these milk products on metabolites involved in inflammation and
           ageing diseases using large-scale metabolomics analysis?

        4. What are the effects of these milk products on the gut microflora (microbiome)?

      Changes in proteomics, metabolomics and the gut microbiome are other pre-specified outcome
      measures but since they are exploratory in nature, we do not specify them under outcomes
      since it is not possible to exactly specify these outcome measures. Exploratory analyses will
      include whether effects are different between men and women, dependent on body composition
      (assessed with whole body dual X-ray absorptiometry, DXA) or long-term dietary intake
      (assessed by fatty acid composition in subcutaneous fat). Participants will be allowed to
      consume more than 500 ml of milk/filmjölk during the intervention periods and, if possible, a
      potential dose-response effect will be evaluated.
    

Intervention name(s): Milk; Soured milk (filmjölk)
Intervention type(s): Other; Other
Intervention description(s): Swedish milk from cow.; Swedish soured milk (from cow milk).
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science