Polyphenol Bioavailability From Chocolate
Condition: Healthy
Study type: Interventional

Summary: 
      Dark chocolate is one of the richest sources of polyphenols though it has been hypothesised
      that the bioavailability of epicatechin from milk chocolate was reduced compared to dark. The
      primary outcome measure is to compare plasma polyphenol levels after consumption of 3
      chocolates (2 milk, 1 dark) while the secondary outcome measures are to characterise the time
      course of polyphenols in the blood and to investigate individual variation in Tmax and Cmax
      for use in future studies.
    

Detailed description: 
      Dark chocolate is one of the richest sources of polyphenols, for example, a standard 40g
      portion of dark chocolate contains 400-800 mg of polyphenols, compared to red wine (170 mg
      /100ml) or an apple (200 mg/piece). Cocoa polyphenols, most notably the catechins, can exist
      in both lipid and water-based environments (amphipathic), meaning they can spare both
      lipophillic and hydrophilic vitamins. There have been a number of human trials conducted
      using chocolate or cocoa and measuring various endpoints. Most have been conducted with dark
      chocolate. An article in Nature found that the bioavailability of epicatechin from milk
      chocolate was substantially reduced compared to dark, and even dark taken with a glass of
      milk (Serafini et al 2003). The hypothesis was that the milk proteins bind to polyphenols,
      making them unavailable. Subsequent studies have not been able to reproduce this, but none
      have been conducted using solid chocolate as the first study, all have been done using a
      drink matrix, which may completely alter the binding interactions of the polyphenols and
      protein. Previous bioavailability trials with dark chocolate have shown a 12 fold increase in
      plasma epicatechin 2 hours after consumption of 80g of chocolate containing 557 mg total
      polyphenols (137 mg epicatechin) (Rein et al 2000) with a concurrent increase in plasma total
      antioxidant capacity and a decrease in TBARS. Another study showed an increase in epicatechin
      2 hours after administering 25g of chocolate chips containing 220 mg flavanols and
      procyanidins, with a concurrent increase in prostacyclin/leukotriene ratio and reduction in
      platelet-related hemostasis (Holt et al 2002).

      This study is designed as a blinded, three arm crossover trial. The primary outcome measure
      is to compare plasma polyphenol levels after consumption of 3 chocolates (2 milk, 1 dark)
      while the secondary outcome measures are to characterise the time course of polyphenols in
      the blood and to investigate individual variation in Tmax and Cmax for use in future studies.
      All volunteers will try all chocolate types with a similar taste & appearance (though milk
      and dark are likely to still be distinguishable for the volunteer, not the investigator).
      Subjects will undergo medical screening, anthropometry, physical activity and dietary
      assessments before randomisation for the order of consumption. Bloods are to be taken as a
      time course for the next 24 hours, as is urine.
    

Intervention name(s): dark chocolate; Milk chocolate 1; Milk chocolate 2
Intervention type(s): Other; Other; Other
Intervention description(s): dark chocolate; Milk chocolate 1; Milk chocolate 2
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Investigator)
Primary purpose: Basic Science
Keywords: Bioavailability; Dark Chocolate; Milk Chocolate; Polyphenols