Impact of Buttermilk on Cholesterol Concentration and Homeostasis
Condition: Cardiovascular Disease
MeSH terms: Cardiovascular Diseases
Study type: Interventional

Summary: 
      The role of low-density lipoprotein cholesterol (LDL-C) in the pathogenesis of cardiovascular
      disease (CVD) and the clinical benefit of lowering LDL-C in high-risk patients have both been
      well established. The key contribution of the intestine to whole body cholesterol homeostasis
      and thus to regulating plasma cholesterol concentrations has also been recognized over the
      last years. It is now clear that cholesterol homeostasis and hence plasma LDL-C
      concentrations are maintained by a fine-tuned balance between intestinal cholesterol
      absorption and endogenous cholesterol synthesis.

      Cholesterol is a highly hydrophobic molecule and for that reason, its absorption is almost
      entirely dependent on its solubilizing capacity in bile acid micelles within the intestine.
      Recent in vitro studies from our laboratory have shown that buttermilk, a unique by-product
      of butter manufacturing resulting from the churning of cream, has a strong inhibitory effect
      on cholesterol micelle solubility. This phenomenon is likely due to the presence of unique
      milk fat globule membrane (MFGM) fragments present in buttermilk that are produced during the
      manufacturing of dairy cream into butter. Most of the work done so far on the subject has
      focused on phospholipids purified from MFGM, while overlooking the complex and entire MFGM
      mixture of bioactive proteins and polar lipids found in buttermilk. To the best of our
      knowledge, no study has yet documented the impact of whole buttermilk on plasma cholesterol
      concentration in human.

      The general objective of this research project is to investigate for the first time the
      impact of buttermilk on plasma cholesterol and other risk factors for CVD in humans. More
      specifically, we propose to investigate the impact of buttermilk consumption on plasma LDL-C
      and other CVD risk factors as well as on plasma surrogates of cholesterol absorption and
      synthesis.
    

Detailed description: 
      The proposed research will be undertaken as a double-blind randomized cross-over study with
      participants being subjected to 2 consecutive treatments of 4 weeks each, in random order,
      during which they will consume 45g of buttermilk and a macro- and micronutrient matching
      placebo. The treatments will be different in their content of MFGM (present in buttermilk,
      absent in placebo). Buttermilk and placebo will be fully characterized and formulated in
      ready-to-use pouches, each pouch containing 22.5 g of artificially flavored products that
      will have to be mixed in a fixed amount of water for consumption. Participants will have to
      consume two pouches every day. Based on a 2500 kcal/day regimen, we have calculated that
      these placebo and buttermilk formulation will contribute to approximately 200 kcal (from 5%
      and 10%) of the daily energy intake of participants, who will be asked to maintain other
      aspects of their nutritional habits constant throughout the study.

      Fluctuations in female hormones have been shown to influence metabolic variables. For that
      reason, outcomes at the end of each dietary phase will be measured during the follicular
      phase of menstrual cycle (day 3 to day 9) in pre-menopausal women. This is another argument
      for using a 4-wk intervention, which essentially corresponds to the mean duration of the
      menstrual cycle of most women. Pre-menopausal women will start the first diet during the
      first week of their menstrual cycle.
    

Intervention name(s): Buttermilk
Intervention type(s): Other
Intervention description(s): Consumption of the 2 experimental periods
buttermilk (45 g/d)
placebo (45 g/d,)
Other intervention name(s): chocolat buttermilk ready-to-use pouches
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: Cardiovascular disease; Buttermilk; Blood lipids; Cholesterol absorption; Cholesterol synthesis