Food & Function Blog

In this review article from Food & Function Editorial Board member Kevin Croft and co-workers from the University of Western Australia the effects of tea and coffee on cardiovascular risk is reviewed. 

Tea and coffee have been associated with the risk of cardiovascular disease (CVD) both positively and negatively. Although tea has generally been associated with neutral or beneficial effects on CVD controversy still exists regarding the effects of coffee. 

This review article highlights the potential mechanisms by which tea and coffee phytochemicals can exert effects for CVD protection, and potential mechanisms affecting intermediate CVD risk factors are highlighted.  Read the full article for free until 21st May! 

Effects of tea and coffee on cardiovascular disease risk
Siv K Bøhn, Natalie C Ward, Jonathan M Hodgson and Kevin D Croft
Food Funct., 2012, Advance Article, DOI: 10.1039/C2FO10288A

Interested in tea and coffee? Food & Function is publishing a themed issue of research presented at the 1st International Congress of Cocoa Coffee and Tea, the issue is Guest Edited by Vincenzo Fogliano and Marco Arlorio and is due to be published lated in 2012.

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Carbohydrates such as sugars, starches and fibers are an important part of a healthy diet. However, government and health organizations around the world have differing guidelines for the intake and type of sugars, which are often generalised and vague. This can cause confusion for nutrition practitioners, especially in relation to “added sugar”. Consuming excess calories ultimately leads to weight gain as the calories are turned into fat by the body, therefore guidelines to asssit nutritionists may help control obesity and its related conditions.

Scientists from the US have now reviewed the health concerns about dietary sugars, and have compiled dietary guidelines for sugars issued by various organizations. In their review, Joanne Slavin and co-workers point out a need for consistent terminology and definitions in order to provide better guidance. They also note that nutrition professionals are often needed to guide the dietary choices of individuals and families, not large populations. Therefore it is important that practitioners consider factors such as health status, habits, calorific needs, and lifestyle in order to effectively translate population-based sugar guidance statements to individuals.

Click the link below to read the full review. It’s free to access for 6 weeks until the 6th May:

The confusing world of dietary sugars: definitions, intakes, food sources and international dietary recommendations, Jennifer Hess, Marie E. Latulippe, Keith Ayoob and Joanne Slavin, Food Funct., 2012, DOI: 10.1039/c2fo10250a

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Scientists in the US have investigated the effects of quercetin (a flavonoid found in many vegetables) on the uptake of green tea polyphenols. Green tea polyphenols (GTPs) have previously been shown to display anticarcinogenic activity against lung, liver and pancreatic cancer; however, their concentration in human plasma is quite low and ways to increase their bioavailabilty is therefore of great interest. 

The research team found that that quercetin increased the bioavailability of GTPs and decreased their methylation leading to an enhanced antiproliferative effect in different cancer cells in vitro and in vivo. Quercetin increased the cellular absorption of epigallocatechin gallate (an active component of green tea) four-fold. The results suggest that eating foods rich in quercetin, such as onions, apples and red wine may help prevent cancer.

This article is free to access for 4 weeks!  Click on the link below to read the article in full:

Quercetin increased bioavailability and decreased methylation of green tea polyphenols in vitro and in vivo, P. Wang, D. Heber and S. M. Henning, Food Funct., 2012, DOI: 10.1039/c2fo10254d

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Scientists from Portugal have studied how anthocyanins are absorbed in the stomach using an in vitro model. Anthocyanins are flavonoid compounds which can be found in blueberries, raspberries and blackcurrants, but their bioavailability is difficult to assess because they exist as different structures in equilibrium depending on pH.

The stomach is often ignored as a metabolizing organ although it has been identified as a site of absorption for different compounds. In this work, adenocarcinoma stomach cells (MKN-28) as a model of the gastric barrier was used to investigate the absorption and metabolism of anthocyanins. The results show that anthocyanins can cross MKN-28 cells in a time dependent manner via a saturable transport mechanism. Also the succesful use of the MKN-28 cell line as a model for gastric digestion could be implemented for other screening procedures and in turn give new insight on bioavailability.

Click the link below to read the article in full. Free to access until April 10th:

A new approach on the gastric absorption of anthocyanins
Iva Fernandes, Victor de Freitas, Celso Reis and Nuno Mateus
Food Funct., 2012, DOI: 10.1039/c2fo10295a

You may also be interested in the article below which is also free to access:

Development of a simple model device for in vitro gastric digestion investigation
Jianshe Chen, Vishwajeet Gaikwad, Melvin Holmes, Brent Murray, Malcolm Povey, Ye Wang and Ying Zhang
Food Funct., 2011, 2, 174-182, DOI: 10.1039/C0FO00159G

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Researchers from France have described a new method of combining an in vitro digestion method with a Caco 2 cell model to study lipid digestion, absorption and conversion to lipid bodies and used this to study the influence of the structure of dietary lipid sources during digestion.

Until recently, studies on dietary fats only considered the impact of their global intake and their total fatty acid composition, not  their structure in foods. By understanding the intake and absorption of dietary oils, diseases such as obesity, diabetes and atherosclerosis (which are characterised by a high fat diet) can be better understood.

In this work, four emulsions based on  milk fat olein (OL) or rapeseed oil (RA) as the dispersed phase and either lecithin or sodium caseinate as the emulsifier were examined. It was demonstrated that in vitro digestion fluids resulting from food emulsions could be used to incubate on Caco-2 cells as a new model for testing emulsion digestion and absorption. It was also shown that the emulsion composition influenced the activation of lipid metabolism and TAG secretion.

To read the full article, click the link below. Read it for free until 23rd March.

Coupling in vitro gastrointestinal lipolysis and Caco-2 cell cultures for testing the absorption of different food emulsions, Cecile Vors, Perrine Capolino, Clemence Guerin, Emmanuelle Meugnier, Sandra Pesenti, Marie-Agnes Chauvin, Julien Monteil, Noel Peretti, Maud Cansell, Frederic Carriere and Marie-Caroline Michalski, Food Funct., 2012, DOI: 10.1039/c2fo10248j

You may also be interested in this review article which is free to access

Review of in vitro digestion models for rapid screening of emulsion-based systems
David Julian McClements and Yan Li
Food Funct., 2010, 1, 32-59, DOI: 10.1039/C0FO00111B

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Scientists in Australia and China have investigated the effects of dietary nitrate intake on nitric oxide (NO) status. NO is important for the control of vasodilation and blood pressure and it can be obtained from the arginine/NOS pathway in cells, but also via nitrates in foods such as spinach and cabbage.

The mechanism of nitrate intake in the mouth is important because about 25% of dietary nitrate is secreted into saliva, of which approximately 20% (5% of the ingested intake) is converted to nitrite in the mouth by bacteria on the tongue. The nitrite is swallowed and is converted to NO in the acidic environment of the stomach or is absorbed and further reduced to NO in the body through a number of mechanisms. This pathway can be interrupted by spitting and not swallowing the nitrite-rich saliva or by the use of antibacterial mouth wash; it is unknown whether the use of antibacterial toothpaste interrupts the pathway.

In this study, the dose–response of dietary nitrate on both NO status and nitrate reduction in the mouth was assessed. It was found that increasing nitrate intake results in a linear dose-related increase in nitric oxide status and nitrate reduction in the mouth. It was also found that the use of antibacterial toothpaste does not inhibit nitrate reduction.

To read the article in full, click the link below: it’s free to access until 20th March.

Nitrate causes a dose-dependent augmentation of nitric oxide status in healthy women, Catherine P. Bondonno, Kevin D. Croft, Ian B. Puddey, Michael J. Considine, Xingbin Yang, Natalie C. Ward and Jonathan M. Hodgson, Food Funct., 2012, DOI: 10.1039/c2fo10206d

You may also be interested in this article which is also free to access:

Dealcoholized red wine reverse vascular remodeling in an experimental model of metabolic syndrome: role of NAD(P)H oxidase and eNOS activity
Marcela Alejandra Vazquez-Prieto ,  Nicolás Federico Renna ,  Carina Lembo ,  Emiliano Raúl Diez and Roberto Miguel Miatello, Food Funct., 2010, 1, 124-129, DOI: 10.1039/C0FO00077A

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Ana Martinez and colleagues from Mexico have reported a theoretical study on the antioxidant mechanism of xanthones. Xanthones are bioactive compounds found in tropical fruits such as mangosteen (Garcinia mangostana) and have shown antioxidant behaviour in a number of experimental studies, however the mechanism of action is not thoroughly understood.

In this work, the antioxidant properties of 20 xanthones and 8 xanthone anions were studied and the more efficient free radical scavengers were identified using a theoretical approach based on single electron transfer (SET). The quantum chemical calculations showed that the reaction between xanthones and OH radicals is thermodynamically unfavourable, however the reaction between xanthone anions (which are present under physiological conditions) and OH radicals is exergonic, and so xanthone anions behave as antioxidants by deactivating the OH free radical species. Understanding the free-radical scavenging mechanisms of these compounds may help combat degenerative diseases such as Alzheimer’s disease which are linked to the antioxidant mechanistic pathway.

Read the article in full by clicking the link below. It’s free to access until March 13th!

Xanthones as antioxidants: a theoretical study on the thermodynamics and kinetics of the single electron transfer mechanism, A. Martínez, E. Hernández-Marin and A. Galano, Food Funct., 2012, DOI: 10.1039/C2FO10229C

 You may also be interested in the following article which is free to acces.

Dietary chromones as antioxidant agents—the structural variable, M. M. Dias,  N. F. L. Machado and M. P. M. Marques, Food Funct., 2011, 2, 595-602, DOI: 10.1039/C1FO10098J

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A study recently published in Food & Function from Advisory Board member Junji Terao and co-workers in Japan shows that water-dispersible hesperetin, an aglycone of citrus flavonoids, is effectively accumulated in human plasma and works as a vasodilator through its metabolites.  The study concludes that hesperetin is a promising flavonoid as a component of functional foods and can be expected to help in maintaining vascular health.

Hesperetin is the aglycone of hesperidin which is present in citrus fruits and has been implicated in many of their beneficial effects including vascular protection; hesperetin has better bioavailability than hesperidin.  Previous work implies that elevation of water solubility results in even higher bioavailability of hesperetin, which has low aqueous solubility due to its hydrophobic flavanone structure. Therefore, in this study micronized water-diseprsable hesperetin was developed and its bioavailability and effects on vasodilation-related functions tested in vitro and in vivo.

Water-dispersible hesperetin, as compared to intact hesperetin, was absorbed into the blood rapidly and at high concentrations.  LC-MS analysis identified a range of metabolites and one, Hp7GA was shown, in cultured endothelial cells, to enhance NO release by inhibiting NADPH oxidase activity.  Furthermore, a volunteer study using women with cold sensitivity showed that a single dose was effective on peripheral vasodilation.  The results of this study suggest that hesperetin is able to exert potential vasodilation effects by the endothelial action of its plasma metabolites. 

Interested in knowing more?  Read the full article for free until March 9th.

Bioavailability of orally administered water-dispersible hesperetin and its effect on peripheral vasodilatation in human subjects: implication of endothelial functions of plasma conjugated metabolites
Hiroko Takumi, Hiroyasu Nakamura, Terumi Simizu, Ryoko Harada, Takashi Kometani, Tomonori Nadamoto, Rie Mukai, Kaeko Murota, Yoshichika Kawai and Junji Terao
Food Funct., 2012, Advance Article, DOI: 10.1039/C2FO10224B

You may also be interested in this review from Professor Terao which is free to access.

Conjugated quercetin glucuronides as bioactive metabolites and precursors of aglycone in vivo
Junji Terao, Kaeko Murota and Yoshichika Kawai
Food Funct., 2011, 2, 11-17, DOI: 10.1039/C0FO00106F

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High blood pressure, known as the ‘silent killer’ is a significant health problem worldwide contributing to an increased risk for heart attack or stroke.  There are numerous preventative and therapeutic drug treatments as well as dietary compounds that have been identified as contributing to cardiovascular health. 

Food-protein derived peptides which have antihypertensive properties have recently received special attention; however, most of their properties have been demonstrated in vitro.  To be confident of the potential these peptides have in cardiovascular health the beneficial effects must be demonstrated in vivo and in clinical trials. 

This review from Blanca Hernández-Ledesma and co-workers from the Institute of Food Science Research in Madrid, Spain, looks at the current state of the data on blood pressure-lowering activity of food-derived peptides demonstrated in vivo through animal models and humans. Other key roles of these peptides such as the mechanism of action and bioavailability are also summarised.

Interested in knowing more?  Read the full article for free until 21^st February:

Antihypertensive peptides from food proteins: a review
Daniel Martínez-Maqueda, Beatriz Miralles, Isidra Recio and Blanca Hernández-Ledesma
Food Funct., 2012, Advance Article, DOI: 10.1039/C2FO10192K

You may also be interested in this review on the role of milk pepetides in cardiovascular health which is freely available:

The potential role of milk-derived peptides in cardiovascular disease
Martha Phelan and David Kerins
Food Funct., 2011, 2, 153-167, DOI: 10.1039/C1FO10017C