Essi Sarkkinen

Berries modify the postprandial plasma glucose response to sucrose in healthy subjects

Sucrose increases postprandial blood glucose concentrations, and diets with a high glycaemic response may be associated with increased risk of obesity, type 2 diabetes and CVD. Previous studies have suggested that polyphenols may influence carbohydrate digestion and absorption and thereby postprandial glycaemia. Berries are rich sources of various polyphenols and berry products are typically consumed with sucrose. We investigated the glycaemic effect of a berry purée made of bilberries, blackcurrants, cranberries and strawberries, and sweetened with sucrose, in comparison to sucrose with adjustment of available carbohydrates. A total of twelve healthy subjects (eleven women and one man, aged 25-69 years) with normal fasting plasma glucose ingested 150 g of the berry purée with 35 g sucrose or a control sucrose load in a randomised, controlled cross-over design. After consumption of the berry meal, the plasma glucose concentrations were significantly lower at 15 and 30 min (P < 0.05, P < 0.01, respectively) and significantly higher at 150 min (P < 0.05) compared with the control meal. The peak glucose concentration was reached at 45 min after the berry meal and at 30 min after the control meal. The peak increase from the baseline was 1.0 mmol/l smaller (P = 0.002) after ingestion of the berry meal. There was no statistically significant difference in the 3 h area under the glucose response curve. These results show that berries rich in polyphenols decrease the postprandial glucose response of sucrose in healthy subjects. The delayed and attenuated glycaemic response indicates reduced digestion and/or absorption of sucrose from the berry meal.

Impact of intensified dietary therapy on energy and nutrient intakes and fatty acid composition of serum lipids in patients with recently diagnosed non-insulin-dependent diabetes mellitus

Compliance with dietary recommendations and the effect of intensified dietary therapy on energy and nutrient intakes and fatty acid composition of serum lipids were studied in 86 obese subjects (aged 40 to 64 years) with recently diagnosed non-insulin-dependent diabetes mellitus (NIDDM). After three months of basic education, the subjects were randomly separated into an intervention group (n = 40) and a conventional treatment group (n = 46). Members of the intervention group participated in 12 months of intensified education; those in the conventional group visited local health centers. Compliance with dietary instructions was monitored through food records. Intensified dietary therapy resulted in greater weight loss, better metabolic control, and a less atherogenic lipid profile than conventional treatment. Intake of energy and saturated fatty acids tended to decline in the intervention group. A higher percentage of patients in the intervention group had a total fat intake of 30% of energy or less after 15 months (32.5% [12 of 38] vs 17.4% [8 of 46]). Similarly, more patients in the intervention group had a saturated fatty acid intake of 10% or less of total energy intake at the end of the study (35.0% [13 of 38] vs 8.7% [4 of 46]). The mean dietary cholesterol intake was within recommendations in both groups at the end of the study. The relative percentage of linoleic acid of serum lipids increased significantly and the relative percentage of palmitic acid of serum triglycerides, phospholipids, and cholesterol esters decreased in the intervention group. These changes indicate that intensified dietary therapy improved the quality of fat in the diet of patients with NIDDM.

Postprandial glucose, insulin and glucagon-like peptide 1 responses to sucrose ingested with berries in healthy subjects

Berries are often consumed with sucrose. They are also rich sources of polyphenols which may modulate glycaemia after carbohydrate ingestion. The present study investigated the postprandial glucose, insulin and glucagon-like peptide 1 (GLP-1) responses to sucrose ingested with berries, in comparison with a similar sucrose load without berries. A total of twelve healthy subjects were recruited to a randomised, single-blind, placebo-controlled crossover study. They participated in two meal tests on separate days. The berry meal was a purée (150 g) made of bilberries, blackcurrants, cranberries and strawberries with 35 g sucrose. The control meal included the same amount of sucrose and available carbohydrates in water. Fingertip capillary and venous blood samples were taken at baseline and at 15, 30, 45, 60, 90 and 120 min after starting to eat the meal. Glucose, insulin and GLP-1 concentrations were determined from the venous samples, and glucose also from the capillary samples. Compared to the control meal, ingestion of the berry meal resulted in lower capillary and venous plasma glucose and serum insulin concentrations at 15 min (P = 0·021, P < 0·007 and P = 0·028, respectively), in higher concentrations at 90 min (P = 0·028, P = 0·021 and P = 0·042, respectively), and in a modest effect on the GLP-1 response (P = 0·05). It also reduced the maximum increases of capillary and venous glucose and insulin concentrations (P = 0·009, P = 0·011 and P = 0·005, respectively), and improved the glycaemic profile (P < 0·001 and P = 0·003 for capillary and venous samples, respectively). These results suggest that the glycaemic control after ingestion of sucrose can be improved by simultaneous consumption of berries.

Postprandial glucose, insulin, and free fatty acid responses to sucrose consumed with blackcurrants and lingonberries in healthy women

BACKGROUND Sucrose induces high postprandial glucose and insulin responses. In vitro studies suggest that berries may reduce the digestion and absorption of sucrose and thereby suppress postprandial glycemia, but the evidence in humans is limited. OBJECTIVE We investigated the effects of sucrose ingested with blackcurrants (Ribes nigrum) and lingonberries (Vaccinium vitis-idaea) on postprandial glucose, insulin, and free fatty acid responses. DESIGN Twenty healthy women participated in a randomized, controlled, crossover meal study. They consumed whole blackcurrants or lingonberries (150 g served as purées) or blackcurrant or lingonberry nectars (300 mL), each with 35 g added sucrose. Sucrose alone (35 g in 300 mL water) was used as a reference. Blood samples were collected at 0, 15, 30, 45, 60, 90, and 120 min. RESULTS In comparison with sucrose alone, ingestion of sucrose with whole berries resulted in reduced glucose and insulin concentrations during the first 30 min and a slower decline during the second hour and a significantly improved glycemic profile. Berries prevented the sucrose-induced late postprandial hypoglycemic response and the compensatory free fatty acid rebound. Nearly similar effects were observed when sucrose was consumed with berry nectars. The improved responses were evident despite the higher content of available carbohydrate in the berry and nectar meals, because of the natural sugars present in berries. CONCLUSIONS Blackcurrants and lingonberries, as either whole berries or nectars, optimize the postprandial metabolic responses to sucrose. The responses are consistent with delayed digestion of sucrose and consequent slower absorption of glucose.

Berries Reduce Postprandial Insulin Responses to Wheat and Rye Breads in Healthy Women

Starch in white wheat bread (WB) induces high postprandial glucose and insulin responses. For rye bread (RB), the glucose response is similar, whereas the insulin response is lower. In vitro studies suggest that polyphenol-rich berries may reduce digestion and absorption of starch and thereby suppress postprandial glycemia, but the evidence in humans is limited. We investigated the effects of berries consumed with WB or RB on postprandial glucose and insulin responses. Healthy females (n = 13-20) participated in 3 randomized, controlled, crossover, 2-h meal studies. They consumed WB or RB, both equal to 50 g available starch, with 150 g whole-berry purée or the same amount of bread without berries as reference. In study 1, WB was served with strawberries, bilberries, or lingonberries and in study 2 with raspberries, cloudberries, or chokeberries. In study 3, WB or RB was served with a mixture of berries consisting of equal amounts of strawberries, bilberries, cranberries, and blackcurrants. Strawberries, bilberries, lingonberries, and chokeberries consumed with WB and the berry mixture consumed with WB or RB significantly reduced the postprandial insulin response. Only strawberries (36%) and the berry mixture (with WB, 38%; with RB, 19%) significantly improved the glycemic profile of the breads. These results suggest than when WB is consumed with berries, less insulin is needed for maintenance of normal or slightly improved postprandial glucose metabolism. The lower insulin response to RB compared with WB can also be further reduced by berries.

Different Effects of Palmitic and Stearic Acid-Enriched Diets on Serum Lipids and Lipoproteins and Plasma Cholesteryl Ester Transfer Protein Activity in Healthy Young Women

The effects of palmitic and stearic acid-enriched diets on serum lipids, lipoproteins, apolipoproteins (apo) A-I and B, and plasma cholesteryl ester transfer protein (CETP) activity were examined in 12 healthy young women. Subjects followed the two experimental diets for 4 weeks according to a randomized crossover design. Both experimental diet periods were preceded by consumption of a baseline diet for 2 weeks. The diets provided 37% of total energy intake (E%) as fat, and differed only with respect to fatty acid composition. There was a substitution of 5E% of palmitic acid or stearic acid in the experimental diets for 5E% of monounsaturated fatty acids in the baseline diet. After the palmitic acid diet, serum total and high-density lipoprotein (HDL) cholesterol and apo A-I concentrations were higher (8%, P = .015, 9%, P = .040, and 11%,P = .011, respectively) and mean serum low-density lipoprotein (LDL) cholesterol concentration tended to be higher (8%, P = .077) as compared with values after the stearic acid diet. Plasma CETP activity increased in the palmitic acid diet as compared with the stearic acid diet (12%, P = .006). In conclusion, palmitic acid and stearic acid-enriched diets had different effects on serum lipids and lipoproteins and also on plasma CETP activity in young healthy women.

Safety Aspects and Cholesterol-Lowering Efficacy of Chitosan Tablets

Objective: The purpose of this study was to determine the effect of two different doses of chitosan on serum fat-soluble vitamin concentrations, cholesterol concentrations, and other safety parameters. Methods: A total of 65 men and women consumed 0, 4.5, 6.75 g per day of chitosan or 6.75 g per day glucomannan for eight weeks in a parallel, placebo-controlled, single-blind study. Altogether, 56 participants completed the study. Results: No differences were detected among the treatments in serum vitamins (vitamin A, vitamin E, 25-hydroxyvitamin D), carotenes (α- and β-carotene), clinical chemistry or hematology measurements. The changes in the total and LDL-cholesterol concentrations among the study groups were not statistically significant. Conclusion: In the present study, the consumption of chitosan tablets was found to be safe, but there was no significant effect on cholesterol concentration.

Feasibility and antihypertensive effect of replacing regular salt with mineral salt -rich in magnesium and potassium- in subjects with mildly elevated blood pressure.

BackgroundHigh salt intake is linked to hypertension whereas a restriction of dietary salt lowers blood pressure (BP). Substituting potassium and/or magnesium salts for sodium chloride (NaCl) may enhance the feasibility of salt restriction and lower blood pressure beyond the sodium reduction alone. The aim of this study was to determine the feasibility and effect on blood pressure of replacing NaCl (Regular salt) with a novel mineral salt [50% sodium chloride and rich in potassium chloride (25%), magnesium ammonium potassium chloride, hydrate (25%)] (Smart Salt).MethodsA randomized, double-blind, placebo-controlled study was conducted with an intervention period of 8-weeks in subjects (n = 45) with systolic (S)BP 130-159 mmHg and/or diastolic (D)BP 85-99 mmHg. During the intervention period, subjects consumed processed foods salted with either NaCl or Smart Salt. The primary endpoint was the change in SBP. Secondary endpoints were changes in DBP, daily urine excretion of sodium (24-h dU-Na), potassium (dU-K) and magnesium (dU-Mg).Results24-h dU-Na decreased significantly in the Smart Salt group (-29.8 mmol; p = 0.012) and remained unchanged in the control group: resulting in a 3.3 g difference in NaCl intake between the groups. Replacement of NaCl with Smart Salt resulted in a significant reduction in SBP over 8 weeks (-7.5 mmHg; p = 0.016). SBP increased (+3.8 mmHg, p = 0.072) slightly in the Regular salt group. The difference in the change of SBP between study groups was significant (p < 0.002).ConclusionsThe substitution of Smart Salt for Regular salt in subjects with high normal or mildly elevated BP resulted in a significant reduction in their daily sodium intake as well as a reduction in SBP.Trial RegistrationISRCTN: ISRCTN01739816

The effect of meat products enriched with plant sterols and minerals on serum lipids and blood pressure

The purpose of the study was to investigate the effect of non-esterified plant sterol-enriched and mineral-enriched low-fat and low-salted meat products compared with control meat products, on serum total and lipoprotein lipids and blood pressure in subjects with mildly to moderately elevated serum cholesterol concentration. A randomised, placebo-controlled, single-blind, repeated measure design was used. Altogether 21 volunteers completed the study. The study began with a pre-trial period of 1–2 weeks, which was followed by three different test periods in the following order: meat products enriched with plant sterols (1.2 g/day), potassium, calcium and magnesium (MP1); meat products with no added plant sterols and minerals (control); and meat products with plant sterols (2.1 g/day), potassium, calcium and magnesium (MP2). Each test period lasted for 3 weeks. During the MP2 period, the serum total and low-density lipoprotein cholesterol concentration decreased 4.9±7.5% (P<0.05) and 4.6±11.3% (not significant), respectively, compared with the control period. No differences in the high-density lipoprotein cholesterol and total triglyceride concentrations or in systolic blood pressure and diastolic blood pressure were found among the test periods. In conclusion, the present study showed that frankfurters and cold cuts enriched with plant sterols from tall oil, potassium, calcium and magnesium, as part of habitual Finnish diet reduced the serum total cholesterol concentration in hypercholesterolemic subjects when the intake of sitosterols was 2.1 g/day, but not with the lower dose.

Safety of barley starch syrup in patients with allergy to cereals.

It is not known whether trace amounts of proteins that may remain in cereal-starch-derived food ingredients even after food processing can trigger allergic symptoms in cereal-allergic individuals. The aim of this study was to find out if barley starch syrup causes allergic reactions in patients with allergy to wheat, barley, rye or oats. Fifteen children with allergy to these cereals, confirmed by double-blind placebo-controlled food challenge (DBPCFC), were selected for the study. When exposed to cereals, seven of the children (47%) showed immediate type reactions, such as urticaria, rash or anaphylaxis. Eight of the children (53%) showed delayed type reactions, such as deterioration of atopic dermatitis or diarrhoea. The fifteen children with allergy to cereals were exposed to barley starch syrup in DBPCFC and none of them showed any objective signs of allergy. On skin-prick tests (SPT), five of the children (33.3%) showed a positive (>or= 3 mm) reaction to at least one of the cereals but none of them to barley starch syrup. This study confirmed with 98% confidence that at least 90% of the patients with verified allergy to cereals will not react with allergic symptoms to barley starch syrup.