California Raisins Health and Nutrition Research
Updated January 2012
Antioxidants
1. “A Randomized, Un-blinded,Single Research Site, Comparator Study of Raisins Versus Alternative Snacks on
Cardiovascular Risk Factors In Generally Healthy Subjects”
Harold Bays MD, FACP, FACE, FNLA
This was a randomized,un-blinded, single research site, comparator study of raisins versus
alternative snacks on cardiovascular risk factors in generally healthy
subjects. Study participants were instructed to orally consume one prepackaged
serving of raisins (90 kcal/serving), or one prepackaged comparator snack (100
kcal/serving) orally administered three times daily before breakfast, lunch,
and dinner with 8 oz. of non-caloric fluid (preferably water) over 12 weeks.
Hypothesis of this study was that routine raisin consumption over 12 weeks would improve cardiovascular risk
factors compared to generally equal calorie alternative snacks.
The objective of this study was to compare the effects of raisins three times per day versus alternative snacks
three times per day on cardiovascular risk factors in generally healthy
subjects.
Primary objective/endpoints were
change at week 12 for raisin versus control snacks regarding:
- Fasting plasma glucose
levels - Plasma glucose levels
2 hours after administration of 75 g oral glucose - Body weight
Secondary objective/endpoints were change at week 12 for raisin versus control snacks regarding:
- Hemoglobin A1c
- Blood pressure
(systolic and diastolic) - Body mass index
Other endpoints included laboratory of special interest
- Potassium
- Alanine
aminotransferase (ALT) - Aspartate
aminotransferase (AST) - Alkaline phosphatase
(Alk Phos) - Fasting serum insulin
(Insulin was not an apriori “endpoint of special interest” in the protocol. It
was added at time of study analysis due to its potential relevance to other
measured metabolic parameters.)
Conclusion:
Overall, this study supports regular consumption of raisins as reducing the important
cardiovascular risk factors of postprandial plasma glucose and blood pressure,
which may help account for the favorable effects of grapes (and thus
potentially raisins) on possibly reducing the risk for cardiovascular disease.
2. “Raisin Effects on Biomarkers of Coronary Heart Disease in Elderly Men and Women”
Maria Luz Fernandez, PhD, University of Connecticut
A randomized, controlled study with 17 men and women aged 50-70 years were involved in the study. They were encouraged to walk or to walk andeat 1 cup of raisins per day or just eat 1 cup of raisins per day. The
intervention improved the lipid risk profile for all groups by resulting in a reduction in both total cholesterol and LDL-C.
The authors suggested that the increase in fiber intake was a likely contributor to the reduction in LDL-C for RAISIN and RAISIN + WALK. Thereduction in blood pressure for RAISIN and RAISIN + WALK may have resulted from
antioxidant effects of the raisin polyphenols. In conclusion, risk factors for CVD were affected significantly by consuming raisins or increasing steps walked. Blood pressure, plasma total cholesterol and LDL-C were significantly decreased by all interventions, while walking lowered plasma TG. Raisins lowered the risk for inflammatory damage by
decreasing one of the markers of inflammation associated with diabetes and
coronary heart disease (tumor necrosis factor – alpha -TNF-α.).
3.Raisins Deliver Antioxidants
Raisins rank among the top antioxidant foods, according to tests conducted by the U.S.
Department of Agriculture (USDA). Antioxidants are important because they
protect cells and their components from oxidative damage – a little like “rust
prevention” for the body. Early findings suggest that eating plenty of fruits
and vegetables high in antioxidants, such as raisins and spinach, may help slow
the processes associated with aging in both body and brain and may help protect
cell components from changes that lead to diseases such as cancer and coronary
heart disease. Antioxidants protect cholesterol and other fats in the blood
from oxidizing. This is critical because oxidized fats in the bloodstream are
much more likely to be deposited on the artery wall or form clots which may
lead to heart attack or stroke. Raisins are among the top contenders for
convenient, accessible, affordable, all-season antioxidant foods.
4.“Raisins, Cyclo-oxygenase – 2 and Cancer Prevention”
Andrew J. Dannenberg, M.D., NewYork-Presbyterian Hospital/ Weill Medical College of
Cornell University, New York, NY.
One of the antioxidant compounds in raisins and some other fruits and vegetables is
catechin. When catechins were fed to tumor-prone mice by the noted cancer
researcher Dr. Andrew Dannenberg and his colleagues, there was a 70 percent
reduction in the number of tumors compared to control animals (not fed
additional catechin). This type of study adds to the body of evidence linking
phytochemical components of fruits and vegetables to reduction in the risk of
colorectal cancer, colorectal adenomas and other gastrointestinal tumors.
5.“Antioxidant Capacity and Cholesterol Concentration in Human Subjects”
Carl L. Keen, Ph.D., Professor and Chair, Department of Nutrition, University of
California – Davis, Davis, California.
Subjects eating raisins (4 servings) daily for 4 weeks increased the plasma antioxidant
capacity. This in turn decreased the level of circulating oxidized low-density
lipoprotein (LDL), so-called bad cholesterol, in subjects. High levels of LDL
cholesterol are associated with increased cardiovascular disease. Oxidized LDL
is especially problematic because the oxidized particles in the bloodstream are
more likely to add to plaque on the artery wall. These data clearly show
raisins are an important part of a diet that encourages 8 to 13 servings of
fruit and vegetables loaded with important phytochemicals and antioxidants.
6.”Value of Raisins for Reduction of Oxidative Stress, Endothelial
Dysfunction, and Inflammation in Obesity”
Janet Walberg Rankin, Ph.D., Professor in Human Nutrition, Foods, and Exercise,
Virginia Tech., Blacksburg, Virginia.
Research expert on oxidative stress and disease, Janet Walberg Rankin, studied theeffect of raisins with their important antioxidant contribution on oxidative stress and inflammation in overweight subjects. It is well known that oxidative
stress triggers an inflammatory response that increases disease risk. Together with graduate student Mary Whitlock, Dr. Rankin looked at whether the modest, easily accessible raisin can benefit obese individuals. They showed lowered levels of markers of inflammation, C-reactive peptide (CRP) and interleukin-6 (IL-6). These findings are important because those eating high fat meals or who are obese have elevated levels of CRP and IL-6. High levels of these components adversely affect proper blood vessel functioning. Thus, those with high oxidative stress tend to have blood vessels that do not appropriately dilate and relax.Foods, such as raisins, that are good sources of antioxidants, especially flavonoids and phenolics,can be helpful in fighting oxidation stress and improving blood vessel function.
7. “Raisin effects on in vitro demineralization of teeth”
Clifton Carey, PhD, Director of Administration, American Dental Association – Paffenbarger Research Center
Strong evidence exists that food particles retained on the teeth will lead to Demineralization of the tooth enamel and dental caries. (caries) (Kashket et al, 1996). This led to the idea that foods which are perceived as ‘sticky’ will be more cariogenic than non-sticky snack foods. Raisins have been perceived bythe general public and by pediatric dentists as the ninth stickiest food out of a list of twenty-one popular snacks. Despite this, there is no evidence that raisins contribute to the demineralization of teeth. In fact measurement of food that is on the tooth 5 minutes after swallowing showed that foods that are less soluble in oral fluids are retained for longer times. Specifically, raisins although perceived as quite sticky, they are easily cleared from the oral cavity. These observations suggest that raisins may not contribute to tooth demineralization significantly because the sugars areremoved from the dentition before the plaque mass has the opportunity to generate sufficient acid to lower the pH below 5.5. There is also research that shows that raisins contain compounds that inhibit the in vitro growth of S. mutans, thus making raisins less cariogenic than other foods. However, the in vitro research with 10% raisin juice showed that it had the potential to demineralize tooth enamel but that this was less than orange juice with its citric acid.
8.“Raisins as a Functional Food for Oral Health”
Christine D. Wu, M.S., Ph.D., Professor, Department of Periodontics, University of Illinois,
College of Dentistry, Chicago, Illinois.
Raisins contain compounds including oleanolic acid that inhibit in vitro growth
of Streptococcus mutans, one of the major bacteria in the mouth
responsible for tooth decay. Oleanolic acid and other compounds in raisins also
inhibit organisms associated with periodontal disease, including Porphyromonas
gingivalis and Fusobacterium nucleatum. Oleanolic acid is effective
in suppressing in vitro plaque formation by Streptococcus mutans.
Prevention of plaque formation on the tooth surface is critical both for
preventing tooth decay and promoting healthy gums.
Food Preservation
9.“Phenolic Content, Antioxidant Activity and Antimicrobial Properties of Raisins
in Food Systems”
Luis Cisneros-Zevallos, Ph.D., Assistant Professor, Department of Horticultural
Sciences, Texas A&M University, College Station, Texas.
Raisins have a considerable concentration of phenolic compounds. This analysis showed
that they were quinic and gallic acid, chlorogenic and caffeic acids, catechin,
and epicatechin. Golden raisins have more of many of these compounds because
the antioxidant effect of the sulfite used in golden raisins inhibits the loss
of these compounds. Raisin juice extracts and concentrates also have
significantly increased numbers of these compounds, so they have the potential
to reduce the growth of harmful microorganisms and prevent browning of cut
produce. According to studies conducted by Luis Cisneros-Zevallos and his team
at Texas A&M, raisin extracts were shown to reduce the growth of known food
pathogens such as Listeria monocytogenes and Escherichia coli
0157:H7 in a variety of model food systems. This has great importance to food
safety and to the produce industry as a non-food additive solution to help
extend the shelf life of food and reduce food-borne disease.
10.”Inhibition of Lipid Oxidation by Raisin Paste in Cooked Ground Meat”
Daren Cornforth, Ph.D., Professor, Nutrition & Food Sciences, Utah State
University, Logan, Utah.
Raisins are recognized as a good source of dietary antioxidants. Adding raisin paste or extract to cooked ground beef or pork at just 1% to 2% of the weight improved its flavor after storage due to inhibition of rancidity by the antioxidants. Addition of the raisin extract to chicken at the same levels was also effective but did cause the meat to darken. In all cases the addition of the small amount of raisins did not affect the flavor of the meat.
11.“Evaluation of the Potential Anti-Microbial Properties of Raisins and Their
Application in Food Safety and Preservation”
Mark A. Daeschel, Ph.D., Professor, Food Microbiology and Safety, Oregon State
University, Corvallis, Oregon.
Pathogenic bacteria, including Escherichia coli 0157:H7, Staphylococcus aureus and Listeria
monocytogenes, were inhibited in jerky systems containing 25% or 50%
raisins. Raisins were shown to have the same preservative properties as sodium
nitrite in meat systems. Raisins’ innate combination of antioxidants, sugar and
acids were shown to be as effective as the sodium nitrite in inhibiting
organisms that cause food- borne disease and in maintaining food safety. This
is good news because producers of jerky, sausages, hot dogs and other cured
meats may be able to reduce or eliminate the use of nitrite additives.
Use of raisins to replace sodium nitrite in cured meats has many health benefits.
First, the nitrite may form cancer-causing nitrosamines during digestion.
Second, unlike the sodium nitrite, raisins add no sodium. This is important for
those on sodium-restricted diets. Third, addition of raisins may improve the
overall nutritional profile of cured meats, such as jerky, since the raisins
provide antioxidants and make it possible to produce a palatable product that
is lower in fat.
Fiber
12. “Raisin Dietary Fiber: Composition and Characteristics”
Mary Ellen Camire, Ph.D., Professor, Department of Food Science and Human Nutrition,
University of Maine, Orono, Maine.
Dietary fiber and other components may reduce the risk of heart disease and cancer by
binding bile acids and causing their elimination from the body. Camire’s study
confirms that eating fibrous foods, such as raisins, caused the elimination of
bile acids. This in turn stimulates the body to replace the excreted bile acids
using its own cholesterol, thus potentially lowering serum cholesterol and the
risk of coronary heart disease. Furthermore, bile acids that are bound by
fibers such as those in raisins will not be metabolized in the gut to a more
toxic form that can cause harmful changes on the colonic wall, and this may
potentially reduce cancer risk.
13.“Raisins as a Source of Inulin”
Medallion Labs, Minneapolis, Minnesota.
California raisins are a good source of inulin, a naturally occurring fiber-like
carbohydrate that helps keep the colon healthy. Independent laboratory analysis
by Medallion Labs, a laboratory known for their analytical work for nutrition
labeling in the U.S., showed that 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. However, inulin is one of the soluble fibers.
Health benefits of inulin are the subject of active research and new functions
are being documented. Some of these include its effects on cholesterol levels
and gut health. Its role as a prebiotic has received much attention because
prebiotics are important to support immune function both in the gut and in the
body.
14. “Beneficial Effects of Raisins on Colonic Function with Possible Implications
for the Prevention of Colon Cancer”
Gene A. Spiller, Ph.D., Head, Sphera Foundation and Health Research Studies Center,
Los Altos, California.
The combination of dietary fiber and tartaric acid in sun-dried raisins plays an
important role in colon function and health. The study was designed to test the
hypothesis that eating 2 to 4 servings of raisins per day may improve colonic
health. Research by Dr. Spiller found a positive correlation between consuming
sun-dried raisins and a reduction in some colon cancer risk factors. For
example, raisins increased fecal weight and caused material to move through the
colon faster (called faster transit time). Increased transit time and increased
fecal weight is important not only to have a properly functioning
gastrointestinal tract and to reduce constipation and hemorrhoids, it also
means that any toxic materials that might be in the diet or produced by
metabolism in the gut will have little time to adversely affect the colon wall.
Raisins reduced the alkalinity in the colon. Both the faster transit and
lowered pH are associated with reduced colon cancer risk. The authors concluded
that 2 servings of raisins per day caused moderate but beneficial changes in
colon function.
Nutrient Composition
15.”The Impact of Pre-exercise Snacks on Exercise Intensity, Stress, and Fatigue
in Children”
Debra R. Keast, PhD; Carol E. O’Neil, PhD, MPH, RD; Julie M. Jones, PhD, CNS, LN
Objective:
This study examined the association of dried fruit consumption with
nutrient intake, diet quality, and anthropometric indicators of
overweight/obesity.
Design:
Analyses of dietary and anthropometric data collected from adult (19+
years) participants (n=13,292) of the 1999-2004 National Health and Nutrition
Examination Survey were conducted. Dried
fruit consumers were defined as those consuming amounts ≥⅛ cup-equivalent
fruit/day and identified using 24-hour recalls.
Diet quality was measured using the Healthy Eating Index-2005
(HEI-2005). Covariate-adjusted means,
standard errors, prevalence rates and odds ratios were determined to conduct
statistical tests for differences between dried fruit consumers and
non-consumers.
Results:
Seven percent of the population consumed dried fruit. Adult shortfall nutrients for which there
were mean intake differences (p<0.01) between consumers and non-consumers
were: fiber (+6.6 g/d), vitamin A (+173µg RAE/d), vitamin E (+1.5 mg AT/d),
vitamin C (+20 mg/d), calcium (+103 mg/d), magnesium (+72 mg/d), and potassium
(+432 mg/d). Dried fruit consumers had
improved MyPyramid food intake, including lower SoFAAS intake, and a higher
SoFAAS score (11.1±0.2 vs 8.2±0.1) than non-consumers. The total HEI-2005 score was significantly
higher (p<0.01) in consumers (59.3±0.5) than non-consumers (49.4±0.3). Covariate-adjusted weight (78.2±0.6 kg vs
80.7±0.3 kg), body mass index (27.1±0.2 vs 28.1±0.2), and waist circumference
(94.0±0.5 vs 96.5±0.2) were lower (p<0.01) in consumers than non-consumers,
respectively.
Conclusions:
Dried fruit consumption was associated with improved nutrient intakes, a
higher overall diet quality score, and lower body weight/adiposity measures.
Glycemic Effects, Sustainable Energy and Healthy Snacks
16.“Effects of Carbohydrate Supplementation Form on Gastrointestinal Tolerance and
Running Performance”
Brandon Too, Sarah Cicai, Kali Hockett, Elizabeth Applegate, Brian A. Davis and Gretchen A.
Casazza
Purpose: We examined the effects of raisins and sport chews on running performance and
gastrointestinal (GI) tolerance.
Methods: This study recruited 11 competitive male (29.3 ± 2.4 yrs) endurance runners and
triathletes to complete an 80-min sub-maximal (75% VO2peak) running bout
followed immediately by a 5K time trial and a 10K time trial 24 hours later.
Subjects ingested 3 randomized treatments (raisins, sport chews, and water
only) with each treatment separated by 7 days.
Heart rate (HR), respiratory exchange ratio (RER), blood glucose,
lactate, free fatty acids (FFA), glycerol, insulin, electrolytes and creatine
kinase, GI symptoms and rating of perceived
exertion (RPE) were recorded every 20 minutes during the sub-maximal exercise
test and at the end of the 5K. We also
measured whole body muscle soreness and fatigue and mood disturbance via
questionnaires.
Results: VO2,
HR, body weight changes, muscle soreness and fatigue, total mood disturbance
and RPE during the submaximal exercise bout did not differ due to treatment.
However, RER was highest during the sport chews treatment, followed by the
raisins and water was the lowest (0.92 ± 0.01, 0.91 ± 0.01, 0.89 ± 0.01 for
raisin, chews and water respectively). FFA and glycerol were higher with water
than both CHO treatments. Blood glucose was higher for both carbohydrate
treatments compared to water. Plasma creatine kinase was higher for all exercise
time points with raisins versus chews and water. Time to complete the 5K time
trial was faster for both carbohydrate treatments (20.6 ± .8, 20.7 ± .8, 21.6 ±
.8 min for raisin, chews and water respectively). GI disturbance was mild (less
than 1 out of 6) for all treatments with only belching higher in both CHO
treatments compared to water.
Conclusion:
Both the raisins and sport chews maintained high blood glucose levels and
improved running performance compared to water only. Running performance
between the raisins and sport chews were similar and their GI tolerance was
good. Raisins provided a good, natural carbohydrate source that had similar
physiological and performance benefits as a commercially available product
17. “The Impact of Pre-exercise Snacks on Exercise Intensity, Stress, and Fatigue
in Children”
Jennifer M. Sacheck, Tamar Kafka, Helen Rasmussen, Jeffrey B.
Blumberg, and Christina D. Economos
Purpose: Few studies have examined how the composition of snacks
affects athletic performance in children. We investigated whether the
macronutrient and flavonoid content of 3 pre-exercise snacks differentially affected
exercise intensity, stress, and postgame fatigue in young soccer players.
Methods: At 1 h prior to a 50-min soccer game, 115 children (9.1
± 0.9 y) were randomly assigned to consume 1 of 3 isocaloric snacks: 1)
nutrient dense/high flavonoid
(HF) raisin/nut bar; 2) low flavonoid (LF) peanut butter graham
bar; or 3) low flavonoid/high sugar (LF/HS) rice cereal bar. Blood glucose and
salivary cortisol and IgA were measured before consuming the snack and immediately
following the game. Game exercise intensity was measured by accelerometry.
Self-administered questionnaires were used to assess diet quality and physical and mental fatigue after
the game.
Results: The children spent approximately 33% of the game in
moderate to vigorous activity and 49% of the game in sedentary activity. The snack
consumed was not related to exercise intensity. Mean post-exercise blood glucose
(P<0.001) and cortisol (P<0.05) increased and IgA levels decreased (P<0.001) from pre-game
values. The pre-exercise snack did not predict the post-exercise outcome for any of these
parameters after controlling for pre-exercise values of the biomarkers, age,
gender, BMI, exercise intensity, game-time water consumption, and diet quality.
Children who reported symptoms of fatigue were more likely to have consumed the LF/HS
snack (P<0.05).
Conclusion: The pre-exercise snacks formulated for this study
did not affect blood sugar or salivary biomarkers of stress following a soccer game
in young children. The nutrient content of the single snack did not differentially
influence these biomarkers or the exercise intensity; however subjective feelings of fatigue
may be associated with low flavonoid/high sugar snacks. Future investigations are warranted
to further explore the effects of pre-exercise snacks on exercise, performance, stress and fatigue in children.
18.“Glycemic Index in the Management of Type 2 Diabetes Mellitus”
Carla Miller, PhD, RD, Ohio State University
The glycemic index of the diet decreased following a 9-week intervention in which
109 diabetics were instructed to increase their intake of fruit and dried
fruit, total dietary fiber (including soluble and insoluble fiber) and the
percentages of energy from protein and total fat (including saturated and
monounsaturated fat) improved. IN addition to a changed GI of the diet, there
was a significant reduction in body weight and body mass index (weight
(kg)/height (m2)) in both men and women and a significant reduction in waist
circumference in men. More fruit including raisins and other dried fruit was
consumed following the intervention, which is consistent with the dietary
pattern recommended in the Dietary Guidelines 2005. These studies show the importance of fruit,
including dried fruit, and dietary fiber in the diet of diabetics. Thus, a carbohydrate-controlled portion of
raisins can readily be incorporated into a well-constructed diabetic diet.
19.“Determination of the Glycemic and Insulinemic Responses to Raisins and the
Application of Raisins as a Pre-exercise Snack for Persons with Impaired
Glucose Tolerance”
Craig Mattern, Assistant Professor, State University of New York at Brockport
Raisins fed as a pre-exercise food to 22 exercisers (approximately half with normal and
abnormal glucose tolerance) resulted in similar increases in blood glucose to
those observed with a popular energy bar. These observed increases in blood glucose for raisins and energy bar
were less than a standardized glucodex solution. The blood insulin response to
the pre-exercise meal with raisins, especially in a sedentary population,
produced statistically lower insulin values than the standardized glucose
solution or the energy bar. All three test substances including Raisins resulted in similar mobilization of free
fatty acids from adipose tissue during exercise. Thus, raisins resulted in a similar glucose
response during exercise when compared to an energy bar and were less than the
standardized glucose solution. The goodnews is that the insulin responses to raisin ingestion prior to, and in the
early phases of exercise, were more favorable than those observed with the
energy bar. Thus, raisins can be an excellent food for use by exercisers to help deliver the right kind of
carbohydrates.
20.”Determination of the Glycemic and Insulinemic Indexes of Raisins in Three
Populations”
Steve Hertzler, Ph.D., Assistant Professor of Nutrition, The Ohio State University,
Columbus, Ohio.
The glycemic index (G.I.) and insulin index (I.I.) of raisins was determined on
three different populations. In 10 sedentary adults, the G.I. of raisins was
determined to be an average of 49.4. A nearly identical G.I. value for raisins
was found for 10 prediabetic individuals. In the 11 endurance athletes, the
G.I. of raisins was 62.3. As expected, the highest insulin index was found in
prediabetic subjects (I.I. = 54.4) and the lowest was found in sedentary
subjects (I.I. = 47.3). While the I.I. for athletes was 51.9, the overall
insulin excursion in trained athletes was not nearly as great, showing the
effects of training on insulin sensitivity and glucose utilization.
Interestingly, California raisins in this study came in as a moderate glycemic food, which is
different from the ‘high’ classification they are given in published tables.
Data for published tables have not been collected on California raisins, and
the population studied is not from the United States.
21.”Raisin Consumption and Exercise Performance of Endurance Athletes”
Mark Kern, Ph.D., Department of Exercise and Nutritional Sciences, University of
California – San Diego, San Diego, California.
Raisins were shown to be a good alternative to sports gels in a study conducted with
endurance athletes under two different conditions. In studies by Mark Kern, San
Diego State professor and author of the CRC Desk Reference on Sports Nutrition
(2005, CRC Press), 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). No gastrointestinal discomfort was reported with either the
gel or raisins. Measures of metabolic substrates after exercise were the same
with both the sports gel and raisins except there were more free fatty acids
after the pre-exercise ingestion of raisins. This increase in the free fatty
acids indicates that raisins subtly, but favorably, improved metabolism. The
authors concluded that raisins have similar performance effects to commercial
sports gel products, but raisins are a better alternative since they provide
more micronutrients, an acid-neutralizing load to the kidneys and are a more
cost-effective and convenient food for use during exercise.
22.”The Effects of a Raisin-Peanut Pre-Event Meal on Indices of Energy and
Fatigue in Young, Trained Soccer Players (10-12 Years of Age) Playing a
Standard Game”
Gene A. Spiller, Ph.D., Head, Sphera Foundation and Health Research and Studies
Center, Los Altos, California.
Feeding raisins along with peanuts and water to 10 to 12 year old children prior to a soccer game resulted in lower increases inblood glucose and insulin than a snack of a white bagel and lemonade. This is important because it means a more steady fuel supply to the exercising muscle of the young players. Lower insulin levels are advantageous because high levels of circulating insulin can promote the laying down of fat and may lead to insulin resistance, a concern among U.S. children today, where rates of obesity and type-2 diabetes are increasing dramatically.