Research on Raisins

Dried Fruits Equivalent to Fresh Fruits

Traditional Dried Fruits– Valuable Tools to Meet Dietary Recommendations for Fruit Intake.

This paper, presented as part of the XXX World Nut and Dried Fruit Congress in Budapest, Hungary on 21 May 2011, was coordinated by Dr. Arianna Carughi and outlines the scientific support for considering dried fruits alongside their fresh counterparts. Also available at www.nutfruit.org.

 

Cardiovascular

Raisins compared with other snack effects on glycemia and blood pressure: a randomized, controlled trial. Anderson JW, Weiter KM, Christian AL, Ritchey MB, Bays HE. Postgrad Med. 2014 Jan;126(1):37-43.

This study suggests that not only is snacking on raisins a nutritious habit, it may also reduce blood pressure and may help keep healthy blood sugar levels. This study compared the effect of snacking on raisins versus commercial snacks on cardiovascular risk factors and blood sugar levels. In this study, 15 people snacked on typical snacks while 31 others snacked on raisins, 3 times a day for three months. Before, after and every four weeks during the 12 week trial, the researchers tested blood pressure, post-eating glucose levels and took blood samples to test glycated hemoglobin levels – also called HbA1c. It is a measure of long term blood sugar control. The researchers found that post-eating glucose levels dropped by 13 milligrams per deciliter of blood (mg/dL). The raisin group also had significantly lower HbA1c levels. The researchers also found that the raisin-snacking group had significantly lower systolic and diastolic blood pressure. Their systolic levels reduced between 6 and 10 mmHg – a significant change.

Key Take-Away: Regular consumption of raisins may reduce glycemia and cardiovascular risk factors, including blood pressure. Raisins have dietary fiber, potassium associated with cardio-protective benefits.

A randomized study of raisins versus alternative snacks on glycemic control and other cardiovascular risk factors in patients with type 2 diabetes mellitus. Bays H, Weiter K, Anderson J. Phys Sportsmed. 2015 Feb;43(1):37-43.

High glucose levels, an indication of metabolic disorder and type 2 diabetes (T2D), is considered a risk factor for cardiovascular disease. A recent study suggests eating raisins three times a day may significantly lower the mean value of post-meal glucose levels for individuals with T2D when compared to consuming popular pre-packaged non-fruit snacks of equal caloric value. Raisins significantly decreased mean post-meal glucose levels by 16 percent. Compared to baseline within group paired analysis, raisins significantly reduced mean hemoglobin A1c by 0.12 percent among those with T2D. Researchers concluded that raisins may be a healthy alternative to processed snacks not only in generally healthy individuals with evidence of metabolic disorder but also among those with T2D.

Key Take-Away: Raisins have a relatively low glycemic index and they also contain fiber. Both of these factors may contribute to blood sugar control.

Satiety

An after-school snack of raisins lowers cumulative food intake in young children. Patel BP, Bellissimo N, Luhovyy B, Bennett LJ, Hurton E, Painter JE, Anderson GH. J Food Sci. 2013 Jun;78 Suppl 1:A5-A10.

A controlled study looked at after-school snacking and satiety among children. They found that eating raisins and grapes as an after-school snack prevents excessive calorie intake and increases satiety – or feeling of fullness – as compared to other commonly consumed snacks. Potato chips and cookies resulted in ~ 81 percent and 121 percent higher calorie intake compared to raisins, respectively. Cumulative calorie intake (breakfast + morning snack + lunch + after-school snack) was 17-25 percent lower respectively, after raisin consumption compared to chips and cookies.

Key Take-Away: All-natural, no-sugar added raisins may help promote healthy weight maintenance in school-age children.

Dental Health

Antimicrobial Constituents of Thompson Seedless Raisins (Vitis vinifera) Against Selected Oral Pathogens. Rivero-Cruz JF, Zhu M, Kinghorn A, D, Wu C D (2008). Phytochemistry Letters, 1(3): 151.

This study found that raisins contain antimicrobial phytochemicals that inhibit bacteria (Streptococcus mutans and Porphyromonas gingivalis) that cause cavities and gum disease. Raisins do not have a negative impact on mouth pH, a key indicator for dental cavity development. Raisins – when consumed on their own – were shown to be almost completely cleared from tooth surfaces within five minutes after chewing and swallowing.

Key Take-Away: Re-think what you have may have heard about raisins and dental health; science shows raisins have properties that inhibit cavity-causing bacteria.

Weight Management

Dried fruit consumption associated with reduced overweight or obesity in adults. Keast DR and Jones JM. NHANES, 1999-2004.

Dried Fruit Consumption Associated with Improved Diet Quality and Reduced Overweight or Obesity in Adults. Jones, JM and Keast, DR. 2009a. NHANES 1999-2004. Amer Diet Association Annual Meeting October 18, 2009 LNC: 5160, 5370, 7120.

Research suggests that dried fruit intake is not associated with higher body weight. On the contrary, recent analysis of NHANES (1999–2004) data indicates that diets high in dried fruits are associated with lower Basal Metabolic Index (BMI), reduced overweight and obesity and improved diet quality.

After adjusting for potential cofounders (socioeconomic status, education, exercise), the data showed that prevalence of overweight/obesity and prevalence of abdominal obesity are lower for those who consumed dried fruits compared to those who did not. The analysis examined the association between dried fruit consumption and body weight and waist circumference in adults, using NHANES data from 1999 to 2004. Dried fruit eaters were defined as those eating greater than or equal to 1/8 cup of fruit equivalent per day either out of hand or contained as an ingredient within other foods.

Key Take-Away: Eating dried fruit, such as California Raisins, is associated with a smaller waistline and less belly fat.

Improved diet quality and increased nutrient intakes associated with grape product consumption by U.S. children and adults. McGill CR, Keast DR, Painter JE, Romano CS, Wightman JD. National Health and Nutrition Examination Survey 2003 to 2008. J Food Sci. 2013 Jun;78 Suppl 1:A1-4.

A study that analyzed the 2003-2008 U.S. National Health and Nutrition Examination Survey (NHANES), which followed 9,622 kids and 1,251 adults found that those who regularly ate grapes, raisins or 100% grape juice – as compiled via interviews – had greater intakes of key nutrients such as fiber and potassium and followed healthier dietary patterns.

Key Take-Away: Eating dried fruit is associated with overall healthier diets.

Sports Nutrition and Exercise

Natural Versus Commercial Carbohydrate Supplementation and Endurance Running Performance. Too BW, Cicai S, Hockett K R, Applegate E, Davis B A, Casazza G A. (2012). Journal of the International Society of Sports Nutrition, 15; 9(1):27. 32.

When it comes to running performance, recent studies have shown that raisins are as effective as commercial sports food. In this study, scientists had eleven male runners (average age = 30) sweat it out at 75% of their VO2 max for 80 minutes on the treadmill followed by a 5 km timed trial Results showed that raisins and chews lead to more energy being used from carbohydrate and improved running performance compared to water only. Running performance was similar between the raisins and chews, with no significant GI difference. Runners that ingested raisins or sports chews ran their 5k on average one minute faster than those that consumed only water. The runners who ate the raisins also used a greater amount of energy from fat vs. carbohydrates compared to the sport chews and is likely due to lower glycemic index and natural fiber content of raisins. This is great news for price-conscious and health conscious runners who want a wholesome energy boost for training and performance. Eating raisins provides the same performance boost during exercise as sports chews.

Key Take-Away: Raisins provide the same workout boost as sports chews, at the fraction of the cost – while also delivering important nutrients. Unlike artificial chews, raisins contribute to the daily intake of potassium and fiber and provide a host of health protective compounds, with no added sugar, flavoring, or color.

Metabolic and performance effects of raisins versus sports gel as pre-exercise feedings in cyclists. Kern M, Heslin C and Rezende RS. Journal of Strength Conditioning Research 21(4):1204-7 (2007).

Raisins were shown to be a good alternative to sports gels in a recent study conducted with endurance athletes. Endurance-trained cyclists (4 males and 4 females) completed two feeding-performance trials where changes in metabolism and cycling performance were compared after consumption of raisins (a moderate to low glycemic index food) versus a commercial sports gel (a high glycemic index food). There were no differences in performance in the 45-minute cycling trial (at 75% VO2max) between raisins and sports gel consumption.

Key Take-Away: Consumption of all-natural California Raisins resulted in the same performance output as sports gels. Unlike artificial gels, raisins contribute to daily intake of potassium and fiber, and provide a host of health protective compounds, with no added sugar, flavoring, or color.

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About The Author
SUZANNE NELSON, ScD, RDN
Suzanne Nelson

Dr. Nelson recently joined the staff of Bryn Athyn College in Pennsylvania as a nutrition and wellness advisor and sports nutritionist. Previously, she was the Director of Sports Performance Nutrition in the athletic department at the University of California, Berkeley. While in California, she was the team nutritionist for the San Francisco 49ers and provided nutrition consultation to the San Francisco Giants and Golden State Warriors. In addition, Dr. Nelson has advised elite amateur athletes at the national, world, and Olympic level. She is a nationally known speaker in sports nutrition and is the author/editor of several books and numerous scientific journal articles. Dr. Nelson is the Nutrition and Health Advisor for Sun-Maid.

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