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 Here's some of the latest and greatest news about raisin nutrition. You'll learn about the role raisins play in protecting against certain illnesses, how raisins support a healthy diet, and important research results. Read what leading nutrition and medical experts are discovering about the importance of raisins to a healthy lifestyle.
Atlanta, GA (June 8, 2005)Compounds found in raisins fight bacteria in the mouth that cause cavities and gum disease, according to research presented today at the 105th General Meeting of the American Society for Microbiology.
"Our laboratory analyses showed that phytochemicals in this popular snack food suppress the growth of several species of oral bacteria associated with caries and gum disease," said Christine D. Wu, Professor and Associate Dean for Research at the University of Illinois at Chicago College of Dentistry and lead author of the study.
Routine chemical analyses identified five compounds in Thompson seedless raisins: oleanolic acid, oleanolic aldehyde, betulin, betulinic acid, and 5-(hydroxymethyl)-2-furfural. All of these are known phytochemicals--antioxidants found in plants.
Oleanolic acid inhibited the growth of two species of oral bacteria: Streptococcus mutans, which causes cavities, and porphyromonas gingivalis, which causes periodontal disease.
The compound was effective against the bacteria at concentrations ranging from about 4 to 1,000 ug/ml. At a concentation of 31 ug/ml, oleanolic acid also blocked S. mutans adherence to surfaces. Adherence is crucial for the bacteria to form dental plaque, the sticky biofilm consisting of oral bacteria that accumulates on teeth. After a sugary meal, these bacteria release acids that erode the tooth enamel.
Wu said that the data counter a longstanding public perception that raisins promote cavities.
"Raisins are perceived as sweet and sticky, and any food that contains sugar and is sticky is assumed to cause cavities'" Wu said. "But our study suggests the contrary. Phytochemicals in raisins may benefit oral health by fighting bacteria that cause cavities and gum disease."
In an earlier unpublished study, Wu's collaborator Dr. Shahrbanoo Fadavi (Pediatric Dentistry, UIC College of Dentistry) found that adding raisins to bran cereal did not increase the acidity of dental plaque. However, the commercial raisin-bran cereal with added sugar was most acidogenic compared with raisins or bran cereal alone.
"Foods that are sticky do not necessarliy cause tooth decay; it is mainly the added sugar (sucrose) that contributes to the problem," Wu said.
The present study was funded by the California Raisin Marketing Board.
Besides collaborator Dr. A Douglas Kinghorn, Adjunct Professor at the UIC College of Pharmacy, other scientists involved in the study were Dr. Jose F. Rivero-Cruz and Dr. Min Zhu (both, UIC College of Dentistry) and Dr. Baoning Su (UIC College of Pharmacy).
Fresno, CA (April 10, 2001) New research presented at the 2001 Experimental Biology conference in Orlando, Florida reports that dietary fiber and other components in raisins have been shown to bind bile acids in laboratory conditions that are similar to the human intestine. The research was conducted by Dr. Mary Ellen Camire, a fiber researcher at the University of Maine. According to the study, the binding of bile acids by dietary fiber and other components found in raisins may have a positive health impact by reducing the risk of both heart disease and cancer.
According to the American Heart Association, high cholesterol is a leading risk factor for heart disease. Camire's study confirms that eating fibrous foods, such as raisins, which bind intestinal bile acids and cause them to be excreted, stimulates the body to use its own cholesterol to replace those acids that have been eliminated. Many studies show that this activity has the potential to lower serum cholesterol levels and possibly reduce the risk of heart disease. In addition, Camire's study suggests the binding of bile acids by dietary fiber may also be valuable in cancer prevention. Intestinal bacteria may change free bile acids in the colon into molecules that might enhance cancer growth. Binding these acids by dietary fiber helps to prevent possible harmful effects of these acids on cells in the colon.
"Unfortunately, most Americans fall far short of meeting the dietary recommendations for the daily amount of dietary fiber recommended by the many different health promotion organizations such as the National Cancer Institute and American Cancer Society," comments Dr. Julie Jones, nutrition consultant for the California Raisin Marketing Board. "Many studies indicate that a diet high in fiber, like that found in fruits and vegetables, is associated with reduced risks of both cancer and heart disease."
The California Raisin Marketing Board was formed to support and promote the use of raisins as a unique taste enhancer and as an ingredient that provides nutritional benefits. The board is committed to developing a variety of informative programs to meet technical, nutrition and creative needs regarding California-grown raisins.
Fresno, CA (March 9, 2001) The number of tumors in mice genetically predisposed to intestinal tumors was reduced by at least 70 percent when fed a diet containing catechin, a phenolic antioxidant found in vegetables and fruits such as raisins, according to a study published in the January 2001 issue of Cancer Research.
Conducted by cancer researcher, Dr. Andrew Dannenberg and colleagues at the Weill Medical College of Cornell University, the study further documents research that determines that components of fruits and vegetables contribute to a lower risk of colorectal cancer and colorectal adenomas. An adenoma is an abnormal growth within the colon that can eventually become a cancerous growth, according to Dr. Julie Jones, nutrition consultant to the California Raisin Marketing Board.
According to the National Cancer Institute, colon cancer is the second most frequently diagnosed malignancy in the United States as well as the second most common cause of cancer death.
Data collected on nearly 2,000 cancer patients from Utah, California and Minnesota, and their matched controls, showed that the 20 percent of the population with the highest consumption of foods from plants (fruits, vegetables, grains and legumes) had a reduction in adenoma and colon cancer risk. Additionally, studies conducted in Canada and Europe have confirmed similar results. In an analysis that combined a number of these human studies, cancer and fiber researcher Dr. Mike Hill, National Research Centre in London, concluded that low intake of fruit was associated with increased cancer risk.
Raisins are a fun, convenient and tasty way to help get catechins into the diet by adding them for extra flavor to your favorite dishes or eating them out-of-hand as a fast and easy snack. According to Dr. Jones no one fruit or vegetable can give all the catechin that is needed, it is important to include a variety of fruits and vegetables in the diet not only for this important cancer-fighting compound but to get fiber and other important nutrients, antioxidants and phytochemicals.
The effectiveness of the recommendations of the DASH diet that has been shown to reduce blood pressure, stroke and heart disease risk, suggests 8-10 servings of fruits and vegetables a day, is becoming more important as we learn more about minor constituents such as catechins, Dr. Jones notes. The DASH diet has been used and is being recommended by such institutions as the Kaiser Permanente Center for Health Research, the Johns Hopkins and Duke University Medical Centers, and the National Heart, Lung and Blood Institute.
The California Raisin Marketing Board was created by a State Marketing Order in 1998 and is grower funded. Its mission is to support and promote the increased use of California-grown raisins and sponsors research on the fruits nutritional benefits.
References
Slattery ML, Berry TD, Potter J, Caan B.Diet diversity, diet composition, and risk of colon cancer (United States). Cancer Causes Control 1997 Nov;8(6):872-82
Ghadirian P, Lacroix A, Maisonneuve P, Perret C, Potvin C, Gravel D, Bernard D, Boyle P. Nutritional factors and colon carcinoma: a case-control study involving French Canadians in Montreal, Quebec, Canada. Cancer 1997 Sep 1;80(5):858-64
Franceschi S Nutrients and food groups and large bowel cancer in Europe. Eur J Cancer Prev 1999 Dec;8 Suppl 1:S49-52
Negri E, Franceschi S, Parpinel M, La Vecchia C. Fiber intake and risk of colorectal cancer. Cancer Epidemiol Biomarkers Prev 1998 Aug;7(8):667-71.
Hill MJ Nutrition and human cancer. Ann N Y Acad Sci 1997 Dec 29;833:68-78
Fresno, Calif. (Nov. 17, 2000) Newly released research at the Symposium on Advances in Clinical Nutrition, sponsored by the American College of Nutrition, found that eating two servings of raisins a day may help lower the risk of colon cancer. This study was designed to confirm an earlier hypothesis that the combination of dietary fiber and tartaric acid in sun-dried raisins plays an important role in colon function and health.
"We found a significant, positive correlation between consuming sun-dried raisins and a change in some colon cancer risk factors," said Gene Spiller, Ph.D., lead study author and researcher at the Health Research and Studies Center in Los Altos, California. "Eating as little as two servings - or 1 cup - of raisins resulted in beneficial changes in colon function that may help combat the estimated 130,000 new cases of colorectal cancer expected to be diagnosed this year."
In this clinical study of 16 healthy men and women, beneficial colonic changes were measured as decreased fecal bile acid concentration, decreased fecal transit time and increased fecal bulk. In other words, eating two servings of raisins helped speed food and waste through the digestive system while decreasing the bile acids in the colon that may promote the growth of cancerous tumors. These results are positive because the decreased transit time and increased fecal bulk mean that dietary carcinogens may be diluted and have less time to act negatively on the colon wall, according to Spiller. " Also, the colon's pH may be lowered, modifying a risk factor for colon cancer. This means colonic diseases typical of a low-fiber diet, such as cancer and diverticular disease, may be prevented," Spiller explained. Raisins are somewhat unique in having this protective effect because they contain tartaric acid. According to a 1996 study by Spiller and colleagues, tartaric acid present in significant amounts only in raisins, grapes and the tropical fruit tamarind plays a significant role in decreasing the time it takes for food and waste to move through the digestive system and reducing harmful bile acid concentrations. "The combination of fiber and tartaric acid in raisins helped to speed transit time and decrease bile acids beyond what would be expected from fiber alone," said Spiller.
In addition to the fiber and essential vitamins and minerals raisins contribute to the diet, recent independent laboratory analysis sponsored by the California Raisin Marketing Board (CRMB) found that raisins are a good source of inulin and several antioxidants, including catechins, plant sterols and flavonoids. Inulin, a fiber-like carbohydrate, ferments in the colon and creates conditions that promote healthy colon cell growth and help prevent growth of abnormal cells that may lead to disease. Only a few other commonly eaten foods, such as onions, garlic and wheat, are known to be good sources of inulin. Also, many other studies have shown that catechin and other phytochemicals are effective in helping to inhibit tumor development in animals.
"Because the environment, including diet, may account for about 65 percent of the risk of getting colon cancer, we need to do our part to eat a diet with plenty of fruit, such as raisins and other dried fruit, vegetables, whole grains, nuts and beans that may help lower the risk of getting colon cancer," said Spiller.
The American College of Nutrition works to provide physicians, nutritionists, dietitians, health care team members and investigators opportunities to increase their understanding of the basic science underlying clinical nutrition and of the clinical practice of nutrition.
Spiller's study was funded by the CRMB, which was created by a State Marketing Order in 1998 and is 100 percent grower funded. Its mission is to support and promote the increased use of California-grown raisins, and it sponsors research of the fruit's nutritional benefits. California's San Joaquin Valley produces the highest quality raisins in the world, with more than 5,000 growers residing in this fertile valley 240 miles long and 50 miles wide.
Each year, nearly 100,000 new cases of colon cancer are likely to be diagnosed. A healthy diet is important in the colon cancer battle, and California Raisins may be an important weapon.
New research sponsored by the California Raisin Marketing Board (CRMB) shows that California raisins are a good source of inulin, a naturally occurring fiber-like carbohydrate that helps keep the colon healthy.
"When inulin from raisins ferments in the colon, beneficial bacteria grow, and harmful bacterial growth is limited," explains Julie Jones, Ph.D., licensed nutritionist and college professor of nutrition. "Thus, inulin fermentation creates conditions that promote healthy colon cell growth and that help prevent growth of abnormal cells that may lead to disease."
According to recent independent laboratory analysis sponsored by the CRMB, a standard 1/4-cup serving of California raisins contains 1.5 grams of inulin. Recommended daily intake levels of inulin have yet to be established. The amount of inulin in a serving of California Raisins is about 58 percent of what USDA surveys show the average American eats daily. Only a few other commonly eaten foods, such as onions, garlic and wheat, are known to be good sources of inulin.
Inulin and other substances, including some fibers, are part of a class of compounds called prebiotics. Prebiotics favor growth of beneficial bacteria, such as lactobacilli and bifidobacteria found in some yogurts. This can be helpful after taking antibiotics when both beneficial and harmful bacteria may be killed. Prebiotics also slow growth of harmful bacteria.
Multiple research studies published in the July 1999 supplement to the Journal of Nutrition describe how inulin and other prebiotics affect colon health. A study by D.J. Jenkins and colleagues showed that inulin fermentation increased the amount of beneficial bacteria in the colon. These bacteria inhibit the growth of organisms that cause food-borne disease, such as E. coli. Another study by H.S. Taper and M. Roberfroid, conducted on animals, showed that short chain fatty acids were produced when inulin ferments. These acids favor the growth of healthy colon cells and inhibit the growth of tumors.
"Acids resulting from inulin fermentation also reduce high colonic pH produced by high-meat diets," explains Jones, consultant to the CRMB. "High colonic pH is a risk factor for colon cancer."
Many nutrition experts believe adults should be eating 8 to 10 servings of fruits and vegetables each day, and various national surveys report that most Americans consume about half of the recommended 25 grams of fiber daily. Adding California Raisins - with naturally-occurring inulin - to the diet can be an easy way to protect the colon while helping to meet daily fruit and dietary fiber goals.
The California Raisin Marketing Board was created by a State Marketing Order in 1998 and is grower funded. Its mission is to support and promote the increased use of California-grown raisins and sponsors research on the fruit's nutritional benefits.
Antioxidants are protective substances naturally found in concentrated amounts in fruit, vegetables and grains.
They may help protect healthy cells from free radicals (unstable oxygen molecules formed in the body when cells use oxygen to produce energy), that may lead to health problems like heart disease, cancer and other ills of aging.
Researchers suggest a daily intake of 3,000 to 5,000 ORAC (Oxygen Radical Absorbance Capacity) units of antioxidants for a significant preventative effect.
Raisins rank among the top antioxidant foods, according to USDA government tests. Antioxidants may protect cells and their components from oxidative damage - a little like "rust protection" for the body. Early findings suggest that eating plenty of fruits and vegetables high in antioxidants -- such as raisins -- may help slow the process associated with aging in both body and brain.
Due to the high interest in antioxidants, the antioxidant activity of raisins will be a primary focus of nutrition research sponsored by the California Raisin Marketing Board.
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