26 Feb 2010 --- Scientists at the Nestlé Research Center in Lausanne, Switzerland, conducted a comprehensive exploration into the nutritional metabolism that occurs after we drink a cup of coffee. The present study revealed that bioactives from coffee have a long-lasting release in the blood, even up to 12-14 hours after consumption. The full article contribution is available in the Molecular Nutrition Food Research journal.

Coffee contains considerable amounts of polyphenols (including chlorogenic and phenolic acids) and if consumed regularly throughout the day, can be a significant source of antioxidants in the total daily diet. Because not much data exists about the metabolism and bioavailability of prominent coffee antioxidants, namely polyphenols, Nestlé Research scientists delved deeper to find answers.

The objective of the present study was to quantify the amount of caffeic acid (CA) and ferulic acid (FA) equivalents in human blood plasma after coffee consumption, to further understand the bioavailability and absorption of these polyphenols. Healthy adults consumed the equivalent of two cups of soluble coffee (4g of coffee dissolved in 400 mL of water). Blood samples were collected for 12 hours and also at 24 hours after consumption, and then scientists quantified total CA and FA equivalents as well as the major metabolites from the colon.

Few other previous studies have investigated the absorption mechanisms of phenolics in coffee. In the literature, these studies reported the detection of certain antioxidants (chlorogenic acids and phenolic acids) 8 hours after coffee consumption, therefore implicating the small intestine in the metabolism and absorption of these molecules. The current Nestlé Research study is the first to evaluate the plasma 12 and 24 hours after coffee consumption. Scientists found that interestingly, key colonic metabolites were detected in subjects 8-12 hours after drinking the coffee. This discovery indicates that the colon and gut microflora, in addition to the small intestine, have a major role in the metabolism and absorption of certain antioxidants in coffee.

“This study allows us to understand more about the metabolism of the extremely complex matrix of bioactives in coffee,” reports Dr. Mathieu Renouf, Nestlé scientist leading the study. “Remarkably, our results showed that even after drinking just one cup of coffee, various bioactives are released in the blood up to 12-14 hours afterwards.” Understanding the absorption and utilization of antioxidants from a widely consumed and pleasing beverage, such as coffee, allows Nestlé to continue providing consumers with foods and beverages that bring health and wellness benefits AND which give the full pleasure of consumption.

Meanwhile the same research group examined the effects of milk and non-dairy creamer on the bioavailability of these bioactives. The full contribution is available in the Journal of Nutrition.

Antioxidants, primarily polyphenols, are found in coffee and are of particular interest because of their health-promoting potential. However, their bioavailability in humans has not been thoroughly studied. Understanding polyphenol bioavailability is important for Nestlé scientists so they can provide nutrition solutions which deliver optimal amounts of phenolic antioxidants from coffee in the best way possible.

In the present study, healthy adult subjects were given either instant coffee, instant coffee plus 10% whole milk, or a pre-mix of instant coffee, sugar and non-dairy creamer. Blood samples were then collected 12 hours after coffee consumption. Polyphenolic equivalents in the blood plasma (caffeic, ferulic and isoferulic acids) were quantified and their bioavailability after consumption of the different coffee types was determined.

Results showed that the addition of whole milk to coffee did not affect the bioavailability of polyphenols, while the addition of non-dairy creamer delayed the appearance of polyphenol equivalents in the blood, but did not influence the total amount delivered. In conclusion, the availability of polyphenols after coffee consumption was the same for all three coffee types. “Coffee is a significant source of phenolic antioxidants in the diet,” said Mathieu Renouf, Nestlé Research scientist leading the study. “Our study confirms that polyphenols from coffee are as bioavailable in coffee with milk as they are in coffee without milk.” Nestlé scientists will continue to study bioactives in coffee and how to provide them to consumers in an effective and good-tasting way.