The effect of three snack bars on glycemic response in healthy adults

Many consumers prefer convenient, portable, and preportioned snack foods. Foods with a lower glycemic response are associated with reduced risk for chronic disease. The glycemic index and glycemic load of three nationally available snack bars were determined. Ten subjects, with mean age (+/-standard deviation) of 29+/-7 years and mean body mass index (+/-standard deviation) of 25.3+/-3.2, were tested on four occasions on nonconsecutive days. After an overnight fast, subjects consumed 50 g of available carbohydrate as a glucose beverage or as a portion of one of three bars: SmartZone nutrition bar (The Hershey Co, Hershey, PA), ZonePerfect nutrition bar (Abbott Laboratories, Abbott Park, IL), or SlimFast meal bar (SlimFast Foods Co, West Palm Beach, FL). Blood glucose was tested at 0, 15, 30, 45, 60, 90, and 120 minutes after consumption. Incremental area under the glucose response curve was calculated for each test bar and compared with that of the glucose beverage to determine glycemic index. The glycemic index (+/-standard error of the mean) for SmartZone was 10.9+/-3.9 and was significantly less (P<0.05) than that of ZonePerfect (43.7+/-7.3) or SlimFast (63.8+/-13.0). The glycemic loads (+/-standard error of the mean) for the SmartZone (2.0+/-0.7) and ZonePerfect (8.3+/-1.4) bars were significantly less (P<0.05) than the glycemic load of the SlimFast bar (21.1+/-4.3). Although the long-term impact of snack foods with a lower glycemic load requires further research, the SmartZone and ZonePerfect bars provide a lower glycemic response for consumers.     

Effect of low-glycemic-index dietary advice on dietary quality and food choice in children with type 1 diabetes

BACKGROUND: The practicality of diets with a low glycemic index (GI) is controversial. Theoretically, low-GI diets may limit food choice and increase dietary fat intake, but there is little objective evidence to support such a theory. OBJECTIVE: The objective was to determine the effect of low-GI dietary advice on dietary quality and food choice in children with diabetes. DESIGN: Children aged 8-13 y with type 1 diabetes (n = 104) were recruited to a prospective, randomized study comparing the effects of traditional carbohydrate-exchange dietary advice (CHOx) with those of more flexible low-GI dietary advice (LowGI). We determined the effect on long-term macronutrient intake and food choice with the use of 3-d food diaries. RESULTS: There were no differences in reported macronutrient intakes during any of the recording periods. After 12 mo, intakes of dietary fat (33.5 +/- 5.6% and 34.2 +/- 6.7% of energy, P = 0.65), carbohydrate (48.8 +/- 5.4% and 48.6 +/- 6.5% of energy, P = 0.86), protein (17.6 +/- 2.5% and 17.3 +/- 3.7% of energy, P = 0.61), total sugars, and fiber did not differ significantly between the CHOx and LowGI groups, respectively. The average number of different carbohydrate food choices per day also did not differ significantly. Subjects in the lowest-GI quartile consumed less carbohydrate as potato and white bread, but more carbohydrate as dairy-based foods and whole-grain breads than did subjects in the highest-GI quartile. CONCLUSION: Children with diabetes who receive low-GI dietary advice do not report more limited food choices or a diet with worse macronutrient composition than do children who consume a traditional carbohydrate-exchange diet.     

Carbohydrate and the Regulation of Blood Glucose and Metabolism

Classifying the glycemic responses of carbohydrate foods using the glycemic index (GI) requires standardized methodology for valid results. Dietary carbohydrates influence metabolism by at least four mechanisms: nature of the monosaccharides absorbed, amount of carbohydrate consumed, rate of absorption, and colonic fermentation. Reducing glycemic responses by reducing carbohydrate intake increases postprandial serum free-fatty acids (FFA) and does not improve overall glycemic control in diabetic subjects. By contrast, low-GI diets reduce serum FFA and improve glycemic control. Thus, current evidence supports FAO/WHO recommendations to maintain a high-carbohydrate diet and choose low-GI starchy foods.     

Intake of fruits, vegetables, and dairy products in early childhood and subsequent blood pressure change

BACKGROUND: Diets characterized by high intakes of fruits and vegetables and low-fat dairy products (for example, the DASH diet) have been shown to reduce blood pressure in adults. The effects of similar diets on children's blood pressure are unknown. METHODS: We used 8 years of follow-up data from 95 children, initially 3 to 6 years of age at enrollment in the prospective Framingham Children's Study in 1986. The yearly clinic visits included 5 measures of blood pressure obtained with an automated device. Diet was assessed by means of replicate sets of 3-day food diaries during each year. RESULTS: Children who consumed more fruits and vegetables (4 or more servings per day) or more dairy products (2 or more servings per day) during the preschool years had smaller yearly gains in systolic blood pressure throughout childhood. By the time of early adolescence, children with higher intakes of fruits and vegetables and dairy products had an adjusted mean (+/- standard deviation) systolic blood pressure of 106 +/- 2.9 mm Hg, whereas those with lower intakes in both food groups had a mean systolic blood pressure of 113 +/-1.5 mm Hg. Those with higher intakes of fruits and vegetables alone or dairy alone had intermediate levels of systolic blood pressure in adolescence. The effects on diastolic blood pressure were weaker. CONCLUSION: These results suggest that a diet rich in fruits, vegetables, and dairy products may have beneficial effects on blood pressure during childhood.     

Glycemic index and glycemic load: measurement issues and their effect on diet-disease relationships

Glycemic index (GI) describes the blood glucose response after consumption of a carbohydrate containing test food relative to a carbohydrate containing reference food, typically glucose or white bread. GI was originally designed for people with diabetes as a guide to food selection, advice being given to select foods with a low GI. The amount of food consumed is a major determinant of postprandial hyperglycemia, and the concept of glycemic load (GL) takes account of the GI of a food and the amount eaten. More recent recommendations regarding the potential of low GI and GL diets to reduce the risk of chronic diseases and to treat conditions other than diabetes, should be interpreted in the light of the individual variation in blood glucose levels and other methodological issues relating to measurement of GI and GL. Several factors explain the large inter- and intra-individual variation in glycemic response to foods. More reliable measurements of GI and GL of individual foods than are currently available can be obtained by studying, under standard conditions, a larger number of subjects than has typically been the case in the past. Meta-analyses suggest that foods with a low GI or GL may confer benefit in terms of glycemic control in diabetes and lipid management. However, low GI and GL foods can be energy dense and contain substantial amounts of sugars or undesirable fats that contribute to a diminished glycemic response. Therefore, functionality in terms of a low glycemic response alone does not necessarily justify a health claim. Most studies, which have demonstrated health benefits of low GI or GL involved naturally occurring and minimally processed carbohydrate containing cereals, vegetables and fruit. These foods have qualities other than their immediate impact on postprandial glycemia as a basis to recommend their consumption. When the GI or GL concepts are used to guide food choice, this should be done in the context of other nutritional indicators and when values have been reliably measured in a large group of individuals.     

Low-energy-density diets are associated with high diet quality in adults in the United States

OBJECTIVE: This study investigated food choices made by individuals consuming diets differing in energy density and explores relationships between energy density and diet quality. DESIGN: Cross-sectional, nationally representative survey. SUBJECTS: 7,500 adults (older than 19 years) in the 1994-1996 Continuing Survey of Food Intakes by Individuals. STATISTICAL ANALYSIS: Energy density values were calculated from reported food intake. Subjects were classified as consuming a low-energy-density diet, medium-energy-density diet, or high-energy-density diet using tertile cutoffs. For each group, the percentage consuming various foods/beverages and the mean amount of foods/beverages they consumed was determined along with mean nutrient intakes. RESULTS: Compared with participants consuming a high-energy-density diet, those with a low-energy-density diet had a lower energy intake but consumed more food, by weight, from most food groups. A low-energy-density diet included a relatively high proportion of foods high in micronutrients and water and low in fat, such as fruits and vegetables. Subjects with a low-energy-density diet consumed fewer (nonwater) beverages such as caloric carbonated beverages. They also consumed less fat and had higher intakes of several important micronutrients, including vitamins A, C, and B-6, folate, iron, calcium, and potassium. CONCLUSIONS: These analyses further demonstrate the beneficial effects of a low-energy-density diet, which was associated with lower energy intakes, higher food intakes, and higher diet quality than a high-energy-density diet. To achieve a low-energy-density diet, individuals should be encouraged to eat a variety of fruits and vegetables as well as low-fat/reduced-fat, nutrient-dense, and/or water-rich grains, dairy products, and meats/meat alternatives.     

Blood pressure response to dietary modifications in free-living individuals

A diet rich in fruits, vegetables, and low-fat dairy foods has been shown to lower blood pressure (BP) when all foods are provided. We compared the effect on BP (measured at home) of 2 different self-selected diets: a low-sodium, high-potassium diet, rich in fruit and vegetables (LNAHK) and a high-calcium diet rich in low-fat dairy foods (HC) with a moderate-sodium, high-potassium, high-calcium DASH-type diet, high in fruits, vegetables and low-fat dairy foods (OD). Subjects were randomly allocated to 2 test diets for 4 wk, the OD and either LNAHK or HC diet, each preceded by a 2 wk control diet (CD). The changes in BP between the preceding CD period and the test diet period (LNAHK or HC) were compared with the change between the CD and the OD periods. Of the 56 men and 38 women that completed the OD period, 43 completed the LNAHK diet period and 48 the HC diet period. The mean age was 55.6 +/- 9.9 (+/-SD) years. There was a fall in systolic pressure between and the CD and OD [-1.8 +/- 0.5 mm Hg (P < 0.001)]. Compared with OD, systolic and diastolic BPs fell during the LNAHK diet period [-3.5 +/- 1.0 (P < 0.001) and -1.9 +/- 0.7 (P < 0.05) mmHg, respectively] and increased during the HC diet period [+3.1 +/- 0.9 (P < 0.01) and +0.8 +/- 0.6 (P = 0.15) mm Hg, respectively]. A self-selected low-sodium, high-potassium diet resulted in a greater fall in BP than a multifaceted OD, confirming the beneficial effect of dietary intervention on BP in a community setting.     

Diet and oral premalignancy in female south Indian tobacco and betel chewers: a case-control study

The diets of 158 tobacco/betel quid-chewing women diagnosed with oral premalignant lesions and 155 quid-chewing but lesion-free controls, frequency matched for age, tobacco/betel habits, and socioeconomic status, were assessed using a food frequency survey. Index scores generated from the food frequency survey indicated that the mean levels of consumption for foods of animal origin (p < 0.001), total vegetables and fruit (p = 0.001), vegetables alone (p = 0.006), fruits alone (p = 0.006), and green leafy vegetables (p = 0.015) were significantly lower in cases than in controls. The mean index score for cobalamin (vitamin B12) was lower in cases with a borderline significance (p = 0.05), whereas the indexes for folate and carotene were not significantly different. The analysis of index scores estimating the number of 100-g servings per week of foods of animal origin [meat, eggs, milk, curd (yogurt), fish] consumed revealed that women who ate fewer servings were more likely to have premalignant lesions than those who ate more animal foods [odds ratio (OR) 3.38, 95% confidence interval (CI) 2.07-5.54, p = 0.001]. The risk for low consumption of vegetables was not as significant as that for foods of animal origin. However, those eating low levels of vegetables and low levels of foods of animal origin were at the greatest risk for lesions (OR 5.38, 95% CI 1.72-22.17, p < 0.05). In South Indian female tobacco/betel chewers, a diet deficient in foods of animal origin appears to be a more significant risk factor for oral premalignancy than is a diet deficient in fruits and vegetables.     

Carbohydrate-loading during the follicular phase of the menstrual cycle: effects on muscle glycogen and exercise performance

The effects of employing a high-carbohydrate diet (carbohydrate-loading) to increase glycogen storage in skeletal muscle are not well established in female athletes. On 4 occasions--2 familiarization trials and 2 experimental trials--6 well-trained female subjects completed 6 x 15-min continuous intervals of cycling (12 min at 72% VO2max, 1 min at maximal effort, and 2 min at 50% VO2max), followed by a time trial 15 min later. The women consumed their habitual diets (HD; 6-7 g carbohydrate/kg lean body mass) for 3 days after the second familiarization trial and before the first experimental trial. During the 3 days following the first experimental trial, the subjects consumed a high-carbohydrate diet (CD; 9-10 g carbohydrate/kg lean body mass) prior to the second experimental trial. Mean (+/-SEM) pre-exercise muscle glycogen concentrations were greater after CD versus HD (171.9+/-8.7 vs. 131.4+/-10.3 mmol/kg wet weight, P < 0.003). Although 4 of the 6 subjects improved their time-trial performance after CD, mean performance for the time trial was not significantly different between diets (HD: 763.9+/-35.6 s; CD: 752.9+/-30.1 s). Thus, female cyclists can increase their muscle glycogen stores after a carbohydrate-loading diet during the follicular phase of the menstrual cycle, but we found no compelling evidence of a dietary effect on performance of a cycling time trial performed after 90 min of moderate-intensity exercise.     

Glycemic index: overview of implications in health and disease

The glycemic index concept is an extension of the fiber hypothesis, suggesting that fiber consumption reduces the rate of nutrient influx from the gut. The glycemic index has particular relevance to those chronic Western diseases associated with central obesity and insulin resistance. Early studies showed that starchy carbohydrate foods have very different effects on postprandial blood glucose and insulin responses in healthy and diabetic subjects, depending on the rate of digestion. A range of factors associated with food consumption was later shown to alter the rate of glucose absorption and subsequent glycemia and insulinemia. At this stage, systematic documentation of the differences that exist among carbohydrate foods was considered essential. The resulting glycemic index classification of foods provided a numeric physiologic classification of relevant carbohydrate foods in the prevention and treatment of diseases such as diabetes. Since then, low-glycemic-index diets have been shown to lower urinary C-peptide excretion in healthy subjects, improve glycemic control in diabetic subjects, and reduce serum lipids in hyperlipidemic subjects. Furthermore, consumption of low-glycemicindex diets has been associated with higher HDL-cholesterol concentrations and, in large cohort studies, with decreased risk of developing diabetes and cardiovascular disease. Case-control studies have also shown positive associations between dietary glycemic index and the risk of colon and breast cancers. Despite inconsistencies in the data, sufficient, positive findings have emerged to suggest that the dietary glycemic index is of potential importance in the treatment and prevention of chronic diseases.     

No difference in body weight decrease between a low-glycemic-index and a high-glycemic-index diet but reduced LDL cholesterol after 10-wk ad libitum intake of the low-glycemic-index diet

BACKGROUND: The role of glycemic index (GI) in appetite and body-weight regulation is still not clear. OBJECTIVE: The objective of the study was to investigate the long-term effects of a low-fat, high-carbohydrate diet with either low glycemic index (LGI) or high glycemic index (HGI) on ad libitum energy intake, body weight, and composition, as well as on risk factors for type 2 diabetes and ischemic heart disease in overweight healthy subjects. DESIGN: The study was a 10-wk parallel, randomized, intervention trial with 2 matched groups. The LGI or HGI test foods, given as replacements for the subjects' usual carbohydrate-rich foods, were equal in total energy, energy density, dietary fiber, and macronutrient composition. Subjects were 45 (LGI diet: n = 23; HGI diet: n = 22) healthy overweight [body mass index (in kg/m(2)): 27.6 +/- 0.2] women aged 20-40 y. RESULTS: Energy intake, mean (+/- SEM) body weight (LGI diet: -1.9 +/- 0.5 kg; HGI diet: -1.3 +/- 0.3 kg), and fat mass (LGI diet: -1.0 +/- 0.4 kg; HGI diet: -0.4 +/- 0.3 kg) decreased over time, but the differences between groups were not significant. No significant differences were observed between groups in fasting serum insulin, homeostasis model assessment for relative insulin resistance, homeostasis model assessment for beta cell function, triacylglycerol, nonesterified fatty acids, or HDL cholesterol. However, a 10% decrease in LDL cholesterol (P < 0.05) and a tendency to a larger decrease in total cholesterol (P = 0.06) were observed with consumption of the LGI diet as compared with the HGI diet. CONCLUSIONS: This study does not support the contention that low-fat LGI diets are more beneficial than HGI diets with regard to appetite or body-weight regulation as evaluated over 10 wk. However, it confirms previous findings of a beneficial effect of LGI diets on risk factors for ischemic heart disease.     

Long-term effects of 2 energy-restricted diets differing in glycemic load on dietary adherence, body composition, and metabolism in CALERIE: a 1-y randomized controlled trial

BACKGROUND: There remains no consensus about the optimal dietary composition for sustained weight loss. OBJECTIVE: The objective was to examine the effects of 2 dietary macronutrient patterns with different glycemic loads on adherence to a prescribed regimen of calorie restriction (CR), weight and fat loss, and related variables. DESIGN: A randomized controlled trial (RCT) of diets with a high glycemic load (HG) or a low glycemic load (LG) at 30% CR was conducted in 34 healthy overweight adults with a mean (+/-SD) age of 35 +/- 6 y and body mass index (kg/m(2)) of 27.6 +/- 1.4. All food was provided for 6 mo in diets controlled for confounding variables, and subjects self-administered the plans for 6 additional months. Primary and secondary outcomes included energy intake measured by doubly labeled water, body weight and fatness, hunger, satiety, and resting metabolic rate. RESULTS: All groups consumed significantly less energy during CR than at baseline (P < 0.01), but changes in energy intake, body weight, body fat, and resting metabolic rate did not differ significantly between groups. Both groups ate more energy than provided (eg, 21% and 28% CR at 3 mo and 16% and 17% CR at 6 mo with HG and LG, respectively). Percentage weight change at 12 mo was -8.04 +/- 4.1% in the HG group and -7.81 +/- 5.0% in the LG group. There was no effect of dietary composition on changes in hunger, satiety, or satisfaction with the amount and type of provided food during CR. CONCLUSIONS: These findings provide more detailed evidence to suggest that diets differing substantially in glycemic load induce comparable long-term weight loss.     

Physiological validation of the concept of glycemic load in lean young adults

Dietary glycemic load, the mathematical product of the glycemic index (GI) of a food and its carbohydrate content, has been proposed as an indicator of the glucose response and insulin demand induced by a serving of food. To validate this concept in vivo, we tested the hypotheses that 1). portions of different foods with the same glycemic load produce similar glycemic responses; and 2). stepwise increases in glycemic load for a range of foods produce proportional increases in glycemia and insulinemia. In the first study, 10 healthy subjects consumed 10 different foods in random order in amounts calculated to have the same glycemic load as one slice of white bread. Capillary blood samples were taken at regular intervals over the next 2 h. The glycemic response as determined by area under the curve was not different from that of white bread for nine foods. However, lentils produced lower than predicted responses (P < 0.05). In the second study, another group of subjects was tested to determine the effects of increasing glycemic load using a balanced 5 x 5 Greco-Latin square design balanced for four variables: subject, dose, food and order. Two sets of five foods were consumed at five different glycemic loads (doses) equivalent to one, two, three, four and six slices of bread. Stepwise increases in glycemic load produced significant and predictable increases in both glycemia (P < 0.001) and insulinemia (P < 0.001). These findings support the concept of dietary glycemic load as a measure of overall glycemic response and insulin demand.     

Reduced glycemic index and glycemic load diets do not increase the effects of energy restriction on weight loss and insulin sensitivity in obese men and women

Reducing the dietary glycemic load and the glycemic index was proposed as a novel approach to weight reduction. A parallel-design, randomized 12-wk controlled feeding trial with a 24-wk follow-up phase was conducted to test the hypothesis that a hypocaloric diet designed to reduce the glycemic load and the glycemic index would result in greater sustained weight loss than other hypocaloric diets. Obese subjects (n = 29) were randomly assigned to 1 of 3 diets providing 3138 kJ less than estimated energy needs: high glycemic index (HGI), low glycemic index (LGI), or high fat (HF). For the first 12 wk, all food was provided to subjects (feeding phase). Subjects (n = 22) were instructed to follow the assigned diet for 24 additional weeks (free-living phase). Total body weight was obtained and body composition was assessed by skinfold measurements. Insulin sensitivity was assessed by the homeostasis model (HOMA). At 12 wk, weight changes from baseline were significant in all groups but not different among groups (-9.3 +/- 1.3 kg for the HGI diet, -9.9 +/- 1.4 kg for the LGI diet, and -8.4 +/- 1.5 kg for the HF diet). All groups improved in insulin sensitivity at the end of the feeding phase of the study. During the free-living phase, all groups maintained their initial weight loss and their improved insulin sensitivity. Weight loss and improved insulin sensitivity scores were independent of diet composition. In summary, lowering the glycemic load and glycemic index of weight reduction diets does not provide any added benefit to energy restriction in promoting weight loss in obese subjects.     

The effect of age, sex, and education on food consumption of a middle-aged English cohort-EPIC in East Anglia

BACKGROUND: Different dietary patterns are associated with differing risks of chronic disease. Yet independent relationships between diet and demographic variables, such as age, sex, and education, are poorly described. METHODS: The first 1968 subjects enrolled to the European Prospective Investigation of Cancer (EPIC) cohort from general practices in East Anglia, UK, provided food frequency and demographic data. RESULTS: Men ate meat, eggs, milk, and sugary foods more frequently, but fruit and vegetables less frequently than women. Older subjects ate red meats and saturated bread spreads more frequently but consumed less poultry and drank less coffee than younger subjects. Better educated subjects ate less meat, more salads, and fewer cakes and sweet foods than those less educated. Five clusters representing different dietary patterns were readily identified. These were (a) younger well-educated, probably containing many vegetarians; (b) "low calorie," two-thirds female; (c) high alcohol, nuts, meat, largely male; (d) preferring fruits, vegetables, unsaturated fats, poultry, and fish, 71% female; (e) preferring meat, potatoes, sweet foods, saturated fats, less well-educated older men. CONCLUSIONS: The reported consumption of many foods varies by age, gender, and education. A pattern of eating that is generally considered less healthful was particularly seen in older men, placing them at increased risk of chronic disease.     

Dietary composition and physiologic adaptations to energy restriction

BACKGROUND: The concept of a body weight set point, determined predominantly by genetic mechanisms, has been proposed to explain the poor long-term results of conventional energy-restricted diets in the treatment of obesity. OBJECTIVE: The objective of this study was to examine whether dietary composition affects hormonal and metabolic adaptations to energy restriction. DESIGN: A randomized, crossover design was used to compare the effects of a high-glycemic-index (high-GI) and a low-glycemic-index (low-GI) energy-restricted diet. The macronutrient composition of the high-GI diet was (as percent of energy) 67% carbohydrate, 15% protein, and 18% fat and that of the low-GI diet was 43% carbohydrate, 27% protein, and 30% fat; the diets had similar total energy, energy density, and fiber contents. The subjects, 10 moderately overweight young men, were studied for 9 d on 2 separate occasions. On days -1 to 0, they consumed self-selected foods ad libitum. On days 1-6, they received an energy-restricted high- or low-GI diet. On days 7-8, the high- or low-GI diets were consumed ad libitum. RESULTS: Serum leptin decreased to a lesser extent from day 0 to day 6 with the high-GI diet than with the low-GI diet. Resting energy expenditure declined by 10.5% during the high-GI diet but by only 4.6% during the low-GI diet (7.38 +/- 0.39 and 7.78 +/- 0.36 MJ/d, respectively, on days 5-6; P = 0.04). Nitrogen balance tended to be more negative, and energy intake from snacks on days 7-8 was greater, with the high-GI than the low-GI diet. CONCLUSION: Diets with identical energy contents can have different effects on leptin concentrations, energy expenditure, voluntary food intake, and nitrogen balance, suggesting that the physiologic adaptations to energy restriction can be modified by dietary composition.     

Evaluation of biological and clinical potential of paleolithic diet

Accumulating evidences suggest that foods that were regularly consumed during the human primates and evolution, in particular during the Paleolithic era (2.6-0.01 x 10(6) years ago), may be optimal for the prevention and treatment of some chronic diseases. It has been postulated that fundamental changes in the diet and other lifestyle conditions that occurred after the Neolithic Revolution, and more recently with the beginning of the Industrial Revolution are too recent taking into account the evolutionary time scale for the human genome to have completely adjust. In contemporary Western populations at least 70% of daily energy intake is provided by foods that were rarely or never consumed by Paleolithic hunter-gatherers, including grains, dairy products as well as refined sugars and highly processed fats. Additionally, compared with Western diets, Paleolithic diets, based on recently published estimates of macronutrient and fatty acid intakes from an East African Paleolithic diet, contained more proteins and long-chain polyunsaturated fatty acids, and less linoleic acid. Observational studies of hunter-gatherers and other non-western populations lend support to the notion that a Paleolithic type diet may reduce the risk of cardiovascular disease, metabolic syndrome, type 2 diabetes, cancer, acne vulgaris and myopia. Moreover, preliminary intervention studies using contemporary diet based on Paleolithic food groups (meat, fish, shellfish, fresh fruits and vegetables, roots, tubers, eggs, and nuts), revealed promising results including favorable changes in risk factors, such as weight, waist circumference, C-reactive protein, glycated haemoglobin (HbAlc), blood pressure, glucose tolerance, insulin secretion, insulin sensitivity and lipid profiles. Low calcium intake, which is often considered as a potential disadvantage of the Paleolithic diet model, should be weighed against the low content of phytates and the low content of sodium chloride, as well as the high amount of net base yielding vegetables and fruits. Increasing number of evidences supports the view that intake of high glycemic foods and insulinotropic dairy products is involved in the pathogenesis and progression of acne vulgaris in Western countries. In this context, diets that mimic the nutritional characteristics of diets found in hunter-gatherers and other non-western populations may have therapeutic value in treating acne vulgaris. Additionally, more studies is needed to determine the impact of gliadin, specific lectins and saponins on intestinal permeability and the pathogenesis of autoimmune diseases.     

Glycemic and insulinemic responses after ingestion of ethnic foods by NIDDM and healthy subjects.

In an attempt to apply the concept of glycemic index (GI) and insulinemic index (II) to local eating habits, we examined the plasma glucose and insulin responses in subjects with non-insulin-dependent diabetes mellitus (NIDDM) and healthy subjects to five mixed meals of different ethnic origins. All meals contained 50 g carbohydrate and were compared with a 50-g glucose load. The GI was highest for the Polish dish and lowest for the Syrian dish (66 +/- 5.5 vs 24 +/- 5.1). However, the II was the highest for the standard meal and lowest again for the Syrian dish (174 +/- 27 vs 66 +/- 25). A high correlation was found between the area under the glucose curve and the predicted GI in both NIDDM and healthy subjects. The GI concept is valid and potentially useful in diet planning and legume foods should be incorporated as a carbohydrate source when diets are being planned for NIDDM subjects or individuals with impaired glucose tolerance.     

Effect of fiber from fruits and vegetables on metabolic responses of human subjects. III. Zinc, copper, and phosphorus balances.

Intakes and excretions of zinc, copper, and phosphorus were determined for 12 men when they consumed a diet low in fiber and when they consumed a diet containing fiber from fruits and vegetables (high-fiber diet). All subjects consumed both diets for 26 days each. The low-fiber diet was supplemented with copper so that it was equivalent to the high-fiber diet in this respect. Mean daily intakes on the low- and high-fiber diets, respectively, were: zinc, 13.2 and 12.6 mg; copper, 1.8 and 1.6 mg; phosphorus, 1.639 and 1.690 g. Mean daily balances on the low- and high-fiber diets, respectively, were: zinc, +3.5 and -0.9 mg; copper, +0.2 and -0.4 mg; phosphorus, +0.361 and +0.292 g. Zinc and copper balances differed significantly on the two diets (P less than 0.001 and P less than 0.005, respectively, but phosphorus balances did not. The fiber supplied by the fruits and vegetables contained more lignin and cellulose and less hemicellulose than would an equivalent amount of fiber from bran. The bran would supply more magnesium, zinc, and copper than this particular diet containing fruits and vegetables.     

Impact of consumption of vegetable, fruit, grain, and high glycemic index foods on aggressive prostate cancer risk

Prostate cancer is a common but complex disease, and distinguishing modifiable risk factors such as diet for more aggressive disease is extremely important. Previous work has detected intriguing associations between vegetable, fruit, and grains and more aggressive prostate cancer, although these remain somewhat unclear. Here we further investigate such potential relationships with a case-control study of 982 men (470 more aggressive prostate cancer cases and 512 control subjects). Comparing the highest to lowest quartiles of intake, we found that increasing intakes of leafy vegetables were inversely associated with risk of aggressive prostate cancer [adjusted odds ratio (OR) = 0.66, 95% CI: 0.46, 0.96; P trend = 0.02], as was higher consumption of high carotenoid vegetables (OR = 0.71, 95% CI: 0.48, 1.04; P trend = 0.04). Conversely, increased consumption of high glycemic index foods were positively associated with risk of aggressive disease (OR = 1.64, 95% CI: 1.05, 2.57; P trend = 0.02). These results were driven by a number of specific foods within the food groups. Our findings support the hypothesis that diets high in vegetables and low in high glycemic index foods decrease risk of aggressive prostate cancer.