John F. Hammerstone

Procyanidin Content and Variation in Some Commonly Consumed Foods

Procyanidins are a subclass of flavonoids found in commonly consumed foods that have attracted increasing attention due to their potential health benefits. However, little is known regarding their dietary intake levels because detailed quantitative information on the procyanidin profiles present in many food products is lacking. Therefore, the procyanidin content of red wine, chocolate, cranberry juice and four varieties of apples has been determined. On average, chocolate and apples contained the largest procyanidin content per serving (164.7 and 147.1 mg, respectively) compared with red wine and cranberry juice (22.0 and 31.9 mg, respectively). However, the procyanidin content varied greatly between apple samples (12.3-252.4 mg/serving) with the highest amounts on average observed for the Red Delicious (207.7 mg/serving) and Granny Smith (183.3 mg/serving) varieties and the lowest amounts in the Golden Delicious (92.5 mg/serving) and McIntosh (105.0 mg/serving) varieties. The compositional data reported herein are important for the initial understanding of which foods contribute most to the dietary intake of procyanidins and may be used to compile a database necessary to infer epidemiological relationships to health and disease.

The effect of cocoa procyanidins on the transcription and secretion of interleukin 1β in peripheral blood mononuclear cells.

Recent data has demonstrated that cacao liquor polyphenols (procyanidins) have antioxidant activity, inhibit mRNA expression of interleukin-2 and are potent inhibitors of acute inflammation. Given the widespread ingestion of cocoa in many cultures, we investigated whether cocoa, in its isolated procyanidin fractions (monomer through decamer), would modulate synthesis of the pro-inflammatory cytokine, interleukin-1 beta. Both resting and phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) were investigated at the levels of transcription and protein secretion. Individual cocoa fractions were shown to augment constitutive IL-1 beta gene expression, although values varied between subjects. Interestingly, the smaller fractions of cocoa (monomer-tetramer) consistently reduced IL-1 beta expression of PHA-stimulated cells by 1-15%, while the larger oligomers (pentamer-decamer) increased expression by 4-52%. These data, observed at the transcription level, were reflected in protein levels in PHA-induced PBMC. The presence or absence of PHA did not alter the effects of the cocoa procyanidins with the exception of the pentamer. This study offers additional data for the consideration of the health-benefits of dietary polyphenols from a wide variety of foods, including those benefits associated specifically with cocoa and chocolate consumption.

Identification and quantitation of flavanols and proanthocyanidins in foods: how good are the datas?

Evidence suggesting that dietary polyphenols, flavanols, and proanthocyanidins in particular offer significant cardiovascular health benefits is rapidly increasing. Accordingly, reliable and accurate methods are needed to provide qualitative and quantitative food composition data necessary for high quality epidemiological and clinical research. Measurements for flavonoids and proanthocyanidins have employed a range of analytical techniques, with various colorimetric assays still being popular for estimating total polyphenolic content in foods and other biological samples despite advances made with more sophisticated analyses. More crudely, estimations of polyphenol content as well as antioxidant activity are also reported with values relating to radical scavenging activity. High-performance liquid chromatography (HPLC) is the method of choice for quantitative analysis of individual polyphenols such as flavanols and proanthocyanidins. Qualitative information regarding proanthocyanidin structure has been determined by chemical methods such as thiolysis and by HPLC-mass spectrometry (MS) techniques at present. The lack of appropriate standards is the single most important factor that limits the aforementioned analyses. However, with ever expanding research in the arena of flavanols, proanthocyanidins, and health and the importance of their future inclusion in food composition databases, the need for standards becomes more critical. At present, sufficiently well-characterized standard material is available for selective flavanols and proanthocyanidins, and construction of at least a limited food composition database is feasible.

Analysis of flavanols in foods : What methods are required to enable meaningful health recommendations?

Flavanols and their related oligomeric compounds, the procyanidins, have received increased attention during the past decade due to their reported health benefits. On the basis of compelling data published during the past decade demonstrating that the consumption of certain flavanol-rich foods can improve markers of cardiovascular health, additional clinical, and epidemiological research is clearly warranted to establish appropriate public health recommendations. However, recommendations on the consumption of these foods appropriate for use by health professionals can only be made on the basis of clinical investigations that accurately identify and quantify—through proper analytical measurement systems—the flavanols in the foods used in these investigations. This manuscript provides an overview of the strengths, weaknesses, and limitations of commonly used analytical methods to characterize the content of flavanols in foods. Two nonspecific measurements widely used by investigators, the Folin-Ciocalteu assay and the Oxygen Radical Absorbance Capacity (ORAC) measurement, are discussed in this context, as is the use of various high-performance liquid chromatography methods that provide more specific data related to the content of flavanols in foods. A comparison of the data obtained from these analytical methods to those of the more rigorous high-performance liquid chromatography analyses demonstrates that these nonspecific methods are ill-suited for providing unequivocal data necessary to evaluate the importance of dietary flavanols in the context of improving cardiovascular health. Meaningful dietary recommendations for the consumption of flavanol-rich foods will only be made possible by additional well-designed clinical and epidemiological studies enabled by detailed compositional data obtained through use of appropriate analytical methods.

Commentary and discussion on the opening session epidemiology, cardiovascular aspects, and analysis of cocoa flavanols

Speaker ID CF—Claudio Ferri JH—John Hammerstone TL—Thomas Luscher NH—Norm Hollenberg MM—Marji McCullough CF: To stimulate debate about the 3 presentations, I wish to comment first on the presentation by Dr Hollenberg, who discussed some early observations on the vascular actions of cocoa flavanols in humans. From Dr Hollenberg, we heard both old and new considerations about cocoa. For instance, he told us that cocoa may have an important action on nitric oxide (NO) bioavailability by increasing NO synthase activity in vascular endothelial cells, as demonstrated by Karim et al. In keeping with this, recent in vivo data, such as those recently reported by our group in the journal, Hypertension, showed that cocoa is able to improve flowmediated vasodilation in healthy subjects and in hypertensive patients. In the same paper, Grassi and colleagues also observed, in both controls and hypertensive patients, that the ingestion of dark, but not white, chocolate bars was able to decrease insulin resistance. In that study, we measured both the insulin resistance index (HOMA-IR) and the insulin sensitivity indexes (QUICKI and ISI). Although the above indexes are not considered the gold standard for measuring insulin-mediated glucose uptake, it was extremely interesting to note that 15-day flavanol-rich dark chocolate administration was able to reduce HOMAIR and increase both QUICKI and ISI. Therefore, I wonder if these metabolic effects of cocoa are dependent on a flavanol-related increment in NO. Does Dr Hollenberg agree with this hypothesis or does he think it is more likely that insulin sensitivity changes after dark chocolate ingestion were due to other cocoa compounds, such as magnesium, theobromine, etc? NH: I think it is not possible to give a definite reply to your question. However, there is abundant literature on the metabolic effects of NO. TL: Is it possible that dark chocolate affects adiponectin levels or resistin and all the mediators and cytokines involved in insulin resistance? NH: Yes. Of course they have such an extraordinary set of interactions, basically promiscuous behavior all the time, that it could be almost anything. CF: Dr McCullough showed us her recent study on the Kuna Indians. I was particularly impressed by the data on blood pressure levels. In particular, I was surprised by the lack of blood pressure changes throughout their life. Indeed, there is not an increase in blood pressure with age in Kuna living in the islands, in contrast to

Effect of Cocoa and Chocolate Beverage Consumption on Human Cardiovascular Health

Cocoa and chocolate have a rich history of use as both a medicine and a vehicle to deliver other medicines. This was, and still is in some communities, in the context of a traditional medicine popular in Central America. In addition, many of these uses were transferred and modified for approximately four centuries in Europe after New World contact. Interestingly, chocolate was consumed predominantly as a beverage; its now-familiar solid format appeared later as a result of food manufacturing innovation in Europe during the 19th century. However, the standard cocoa and chocolate beverage formats we are familiar with bear little, if any, resemblance to the recipes developed by ancient Central Americans. Dillinger et al. (1) convincingly illustrate the versatility of cocoa and chocolate as medical and nutritional uses in their research. As shown in Table 1, the number of different indications, multiplied by different preparations in the accompanying text, is impressive. Continuing research by Dillinger et al. and others on the use of these products by the native populations before European contact may provide additional and important insights on cocoa’s cultural origins and geographical aspects and its medical uses (L. Grivetti and H. Yana-Shapiro, personal communication).