Participants In New Human Study Experience Short-Term Improved Vascular Function After Consuming Red Raspberries

Frozen raspberries

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A recent randomized controlled trial, published in the Archives of Biochemistry and Biophysics, provides insights on the promising outcomes ofshort-term improvements in blood vessel function among healthy males who consumed dietary achievable amounts of red raspberries.

The subjects – ten healthy males aged 18 to 35 – consumed drinks prepared with 200g and 400g of frozen raspberries containing 201 or 403 mg of total polyphenols, or a matched control drink in terms of macro and micronutrient content, color, and taste.

Researchers investigated the vascular effects of the subjects at baseline, 2 hours-post consumption and 24 hours-post consumption of the raspberry and control test drinks. Participants consuming the red raspberry drink showed improved flow-mediated dilation (FMD), an established biomarker of cardiovascular disease risk. FMD increased significantly at 2 hours post-consumption of the raspberry drink when compared with the change in FMD due to the control drink, and this maintained at 24 hours after consumption.

At 2 hours post-consumption of both raspberry drinks, ellagic acid, found in plasma and urine correlated with FMD. At 24 hours post-consumption of the 200g raspberry drink, urolithin-A-3-glucuronide and urolithin-A-sulfate correlated with FMD. No significant differences were found between FMD improvements after consumption of the 200g and 400g raspberry drinks.

“The research study suggests that ellagitannins, a type of natural compounds present in red raspberries, may play a role in driving the positive effects seen on blood vessel function in the study’s participants,” commented Dr. Ana Rodriguez-Mateos, principal investigator and senior author of the study from the Department of Nutritional Sciences, Faculty of Life Sciences and Medicine of King’s College London.

“We’re excited about these findings and what they may potentially add to the growing list of benefits from consuming red raspberries,” commented Tom Krugman, Executive Director of the National Processed Raspberry Council (NPRC).

Further studies will need to show whether these results translate into long-term health benefits in the general populationby looking at larger study groups over longer timeframes.

The research was supported in part by funds from The National Processed Raspberry Council.

 

Reference:

Istas, G. Feliciano, R. Weber, T. Garcia-Villalba, R. Tomas-Barberan, F. Heiss, C. Rodriguez-Mateos, A. Plasma urolithin metabolites correlate with improvements in endothelial function after red raspberry consumption: a double-blind randomized controlled trial.  Archives of Biochemistry and Biophysics. May, 2018.

https://www.sciencedirect.com/science/article/pii/S0003986118302169

In the Spotlight: Raspberry Recipes of 2018

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It’s been a big year to date for raspberries! Frozen and dehydrated raspberries, as well as raspberry jam are showing up in recipes from sweet to savory for breakfast, lunch, dinner, sips, snacks, and…who can forget dessert?!

Check out some of our year’s favorite recipes to date!
Breakfast

 

Waking up isn’t so bad with recipes like these.

Raspberry Orange Sweet Rolls from Oh Lady Cakes!

Raspberry Banana White Chocolate Chip Coconut Muffins from The Forked Spoon

Matcha Raspberry Blender Muffins from Lean Green Nutrition Fiend

Steel Cut Overnight Oats from Treble in the Kitchen

Peanut Butter & Jelly Breakfast Oatmeal Bars from C&J Nutrition for POPSugar

Lunch or Dinner

 

The sweet-tart flavor profile of raspberries is perfect in savory dishes.

Raspberry Maple Mustard Salmon from Katie Cavuto, RD

Instant Pot Raspberry Glazed Ribs from Mom’s Kitchen Handbook

Raspberry Almond Vinaigrette from Healthy Seasonal

Afternoon Snack

 

Still hungry? We’ve got you covered.

PB &J Overnight Oats from Lively Table

Raspberry Ginger Power Smoothies from The Kitchn

Raspberry Fluff Marshmallows from Milk & Honey Nutrition

Dessert

 

We’ll take one of everything please.

Fudgy Vegan Raspberry Almond Brownies from Hummusapien

Soft Yogurt Cookies with Raspberry Glaze by Molly Yeh for Food52

Conversation Heart Cookie Pops (with a Red Raspberry Glaze!) from ImmaEatThat

Lemon Cake with Red Raspberry Cream Frosting from Nourished Kitchen

Raspberry Mango Cake from Liv for Cake

Raspberry Cheesecake from Joy Filled Eats

No-Drip Raspberry Popsicles from Nourished Kitchen

Raspberry White Chocolate Ice Cream Pops from Love & Olive Oil


Cocktails

Cheers!

Raspberry Peach Frose from A Classic Twist

Frozen Sangria Slush from Delish Knowledge

 

Get some grocery shopping and additional meal inspiration from these articles below!

 

How Vegetarian Food Blogger Cookie and Kate Starts Her Day in The Kitchn

19 Foods Nutritionists Always Buy at Trader Joe’s in Reader’s Digest

5 Things Nutritionists Load Up on at Trader Joe’s in Southern Living Magazine

 

New Exploratory Study Identifies Red Raspberry Polyphenols and Their Metabolites

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An exploratory study published in Food & Function identified and quantified red raspberry polyphenols and their metabolites after human consumption. It characterized an array of polyphenols in different forms of red raspberries and a greater number of phenolic compounds in human biological samples than previous studies. Understanding the metabolic fate of polyphenol compounds in human biological specimens may aid in designing future studies, including mechanism of action studies.

In this study, the most abundant polyphenols in red raspberries were anthocyanins and ellagitannins, which have gained some attention as phytochemicals. Anthocyanins may possess anti-inflammatory, anti-oxidative and metabolic stabilizing activity. Some limited animal and in-vitro studies have shown breakdown products of ellagitannins may help reduce oxidative stress and inflammation.

This study identified polyphenols in four different forms of red raspberries (frozen, fresh, freeze-dried, pureed) and found that while the different forms have relatively similar polyphenol profiles, the concentration of anthocyanins was highest in the frozen red raspberry form and the concentration of ellagitannins was highest in the freeze-dried red raspberry powder form.

“To design studies investigating their biological effects, we needed to have a better understanding of the variability in key polyphenols among red raspberry fruit forms and their metabolic fate in humans after acute and chronic intake of red raspberries,” commented Britt M. Burton-Freeman, PhD, MS of the Center for Nutrition Research, Institute for Food Safety and Health, Illinois Institute of Technology, and senior author of the paper.

This study assessed biological samples (urine, plasma) obtained from two human pilot studies after consuming red raspberries for more than one week. The study tentatively identified 62 red raspberry polyphenol metabolites, including some phenolic compounds that were detected for the first time, in plasma and urine.

The results of this study may offer new information for understanding the metabolic fate of red raspberry compounds and their composition in different biological specimens.

“The knowledge of metabolites detected in human biological samples may aid research platforms in determining which metabolites may be most relevant, and possible mechanisms of action,” said Burton-Freeman.

“We are excited about the direction this study provides in establishing methods for future trials,” commented Tom Krugman, Executive Director of the National Processed Raspberry Council (NPRC). “Our Council is committed to delivering the highest quality nutrition and health science that consumers can apply in making healthy food choices.”

For the study abstract, click here.

Several Studies Explore the Potential Benefits of Red Raspberries

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Eight studies –including human trials – explore potential for satiety, blood sugar control, and anti-inflammatory properties of raspberries

“We are excited about this new flurry of studies, which builds on previously published research aimed to better understand the potential health benefits of red raspberries,” said Tom Krugman, Executive Director of the National Processed Raspberry Council (NPRC).  “Our Council is committed to delivering the highest quality nutrition and health science that consumers can use to make informed choices when aiming for a healthy diet.”

While additional research, particularly in humans, is warranted, preliminary evidence from these studies suggests that the actions of essential nutrients, fiber, and polyphenolic phytochemicals found in red raspberries may play a role in supporting key metabolic functions, including anti-inflammatory, anti-oxidative and metabolic stabilizing activity. While this emerging research is promising, and contributes to the overall understanding of the health benefits of red raspberries, conclusions cannot be drawn at this time.

Blood Sugar Control

In this human trial, investigators from the Center for Nutrition Research at the Illinois Institute of Technology looked at two study groups: obese individuals with impaired fasting glucose and hyperinsulinemia (PreDM) and healthy weight individuals with normo-glycemia and insulinemia. Participants experienced a significant reduction in postprandial glucose when 2 cups (250g) of red raspberries were consumed with meals compared to no raspberries. The glucose lowering was accompanied with less insulin suggesting improved insulin sensitivity in individuals with pre-diabetes and insulin resistance.

  • Xiao, D. Huang, Y. Park, E. Edirisinghe, I. and Burton-Freeman, B. Red Raspberries and Insulin Action: Understanding the Role of Red Raspberry Consumption on Postprandial Metabolic Indices. The FASEB Journal, April 2017, 31 no. 1 Supplement 973.9. http://bit.ly/PostprandialMetabolicIndices 

Satiety

  • Huang, L. Xiao, D. Park, E. Edirisinghe, I. and Burton-Freeman, B. The Effect of Red Raspberry on Satiety. The FASEB Journal, April 2017, 31 no. 1 Supplement 794.8. http://bit.ly/RaspberriesSatiety

Gut Health

In an eight-week pilot study, researchers from the Institute for Food Safety and Health from the Illinois Institute of Technology examined the impact of consumption of red raspberry purée or fructo-oligosaccharide on the gut microbiota and the subsequent bioavailability of red raspberry polyphenols in healthy volunteers.  Consumption of the red raspberry puree and the fructo-oligiosaccharide for 4 weeks resulted in decreased Firmicutes and increased Bacteroidetes, which was more pronounced after red raspberry intake. Additionally, a type of bacteria called Akkermansia that has been associated with metabolic health was increased during red raspberry intake only. These preliminary results are promising. Further research is needed to support the hypothesis that the consumption of raspberry puree may change the composition of the gut microbiota.

  • Zhang, X. Sandhu, A. Schill, K. Edirisinghe, I. and Burton-Freeman, B. The Reciprocal Interactions between Red Raspberry Polyphenols and Gut Microbiome Composition: Preliminary Findings. The FASEB Journal, April 2017, 31 no. 1 Supplement 965.29. http://bit.ly/GutMicrobiomeComposition

Dr. Giuliana Noratto and colleagues of the Department of Food and Nutrition Science at Texas A&M University studied if dietary supplementation with red raspberries could modulate the fecal microbiota of obese mice with diabetes and dyslipidemia. In this animal study, raspberry supplementation was associated with higher levels of Lachnospiraceae – a family of bacteria that can be depleted during diseases of the intestinal tract, such as inflammatory bowel disease. These findings provide a basis for formulating hypotheses for conducting additional studies, particularly in human trials.

  • Noratto, G. Garcia-Mazcorro, J. Chew, B. and Mertens-Talcott, S. Dietary Supplementation with Raspberry Whole Fruit Modifies the Relative Abundance of Fecal Microbial Communities in Obese Diabetic (db/db) Mice. The FASEB Journal, April 2017, 31 no. 1 Supplement 965.19. http://bit.ly/MicrobialCommunities

Type 2 Diabetes

In an animal study, mice fed 5% freeze dried raspberry for 12 weeks, showed signs of improved insulin resistance and reduced inflammation in skeletal muscle while consuming a high-fat diet. These data corroborate a short-term study in humans reported by Xiao and colleagues at the same meeting supporting further work in humans to provide additional insight into these findings.

  • Min Du, Tiande Zou, Bo Wang, Xingwei Liang, and Mei-Jun Zhu. Raspberry intake reduces skeletal muscle lipid accumulation and improves insulin sensitivity in mice fed high fat diet. The FASEB Journal, April 2017, 31 no. 1 Supplement 972.19. http://bit.ly/MuscleLipidAccumulation

A research team from the University of Michigan studied the potential biologically active properties of red raspberries with in vitro assays including antioxidant and anti-inflammatory capacities. Follow-up research explored the potential relationship between feeding freeze-dried whole raspberry powder and cardiometabolic risk in obesity prone rats. Red raspberries were found to upregulate the expression of specific cardiac-protective molecular proteins (myocardial adiponectin, its receptor 2, and apolipoprotein E). Rats fed the red raspberries also experienced altered nicotinamide phosphoribosyltransferase mRNA, a protein associated with multiple functions in conditions related to obesity and type 2 diabetes.   More research is needed to determine if compounds in red raspberries play a role in human cardiometabolic pathways.

  • Kirakosyan, A. Seymour, EM. Gutierrez, E. and Bolling, S. Associations of Dietary Intakes of Red Raspberry Fruits with Risk of Type 2 Diabetes Mellitus. The FASEB Journal, April 2017, 31 no. 1 Supplement 973.4. http://bit.ly/RiskofType2Diabetes

Inflammation

In a mouse model, red raspberry supplementation of 5% dry feed weight was found to suppress inflammation and facilitate epithelium repair compared to mice with induced colitis (inflammation of the colon) and fed a standard chow diet.  These observations are not conclusive, and further research is needed to determine if red raspberry supplementation supports epithelial function in humans.

  • Bibi, S. Du, M. Kang, Y. Sun, X. Xue, Y. Soussa Moraes, LF. and Zhu, M. Dietary Red Raspberry Enhances Intestinal Epithelium Repair in Chronic Colitis. The FASEB Journal, April 2017, 31 no. 1 Supplement 972.19. http://bit.ly/IntestinalEptheliumRepair

Anthocyanin Profiles of Processed Raspberries

Anthocyanin profiles among common processed forms of raspberries (frozen, juice concentrate, seeded puree, and seedless puree) on the U.S. market were investigated. Thirty-four samples – both domestic and imported – were reviewed. Seven individual anthocyanins were identified in the samples. While anthocyanin profiles varied slightly, contents varied considerably. This may reflect differences in varieties, origins, processing methods among other influential factors.

  • Wu, X. Sun, J. Ahuja, J. Haytowitz, DB. Burton-Freeman, B. Chen, P. Pehrsson, PR. Anthocyanin profiles and contents in processed raspberries on the U.S. market. The FASEB Journal, April 2017, 31 no. 1 Supplement 454.6. http://bit.ly/AnthocyaninProfiles