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Biomedical subjects

K Hermansen

Publications and source records attributed to K Hermansen.

At least 37 records · Page 2Linked to original sources

Comparison of the effects of a monounsaturated fat diet and a high carbohydrate diet on cardiovascular risk factors in first degree relatives to type-2 diabetic subjects.

OBJECTIVE: Recent studies have demonstrated beneficial metabolic effects of dietary monounsaturated fatty acids (MUFA) in Type-2 diabetes mellitus (Type-2 DM). The question arises if dietary MUFA also has desirable effects on risk markers in subjects with high risk of developing Type-2 DM. SETTING: University department of endocrinology. SUBJECTS: Sixteen healthy, first-degree relatives (six men, 10 women, age (mean+/-s.d.): 35+/-2 years) with normal oral glucose tolerance tests. INTERVENTIONS: Randomised study with two 4-week treatment periods with either a carbohydrate-rich (CHO) diet (55 E% carbohydrate, 30 E% fat, 15 E% protein) or a diet rich in olive oil [MUFA 40 E% fat (25 E% as MUFA), 45 E% carbohydrate, 15 E% protein]. The periods were divided by a 4-week wash-out period. RESULTS: Similar lowering effects on total cholesterol, low density lipoprotein (LDL)-cholesterol, triglyceride and apoB levels were seen after the two diets. Slightly higher levels of high-density lipoprotein (HDL)-cholesterol (1.4+/-0.4 vs 1.3+/-0.4 mmol/l, P<0. 0001) and apoA-1 (1.2+/-0.3 vs 1.1+/-0.3 mmol/l, P<0.05) were found in the MUFA-diet. Furthermore, the insulin sensitivity, as assessed by Bergman's minimal model, and the first response insulin areas were similar, as were the 24-h blood pressures and the von Willebrand Factor (vWF) levels. CONCLUSIONS: Isocaloric diets rich in MUFA or rich in carbohydrate, respectively, seem to have similar effects on cardiovascular risk factors in persons at high risk of developing Type-2 DM. A potential risk, however, on body weight of high-fat diets should be kept in mind. SPONSORSHIP: This study was supported by grants from the Danish Diabetes Association, Institute of Clinical Experimental Research, Aarhus University, The Danish Heart Foundation, The Danish Medical Research Council, Velux Foundation, Poul and Erna Sehested Hansens Foundation, Mogens Svarre Mogensens Foundation.

Adult↗

Differential effects of saturated and monounsaturated fatty acids on postprandial lipemia and incretin responses in healthy subjects.

BACKGROUND: Elevations of postprandial triacylglycerol-rich plasma lipoproteins and suppressions of HDL-cholesterol concentrations are considered potentially atherogenic. Long-term studies have shown beneficial effects of monounsaturated fatty acids (eg, oleic acid) on fasting lipid and lipoprotein concentrations in humans. A direct stimulatory effect of oleic acid on the secretion of glucagon-like peptide 1 (GLP-1) was shown in animal studies. OBJECTIVE: We compared the postprandial responses of glucose, insulin, fatty acids, triacylglycerol, gastric inhibitory polypeptide (GIP), and GLP-1 to test meals rich in saturated and monounsaturated fatty acids. DESIGN: Ten young, lean, healthy persons ingested 3 meals: an energy-free soup consumed with 50 g carbohydrate (control meal), the control meal plus 100 g butter, and the control meal plus 80 g olive oil. Triacylglycerol and retinyl palmitate responses were measured in total plasma, in a chylomicron-rich fraction, and in a chylomicron-poor fraction. RESULTS: No significant differences in glucose, insulin, or fatty acid responses to the 2 fat-rich meals were seen. Plasma triacylglycerol responses were highest after the butter meal, with chylomicron triacylglycerol rising 2.5-5-fold. Retinyl palmitate responses were higher and more prolonged after the butter meal than after the control and olive oil meals, whereas both postprandial HDL-cholesterol concentrations and GLP-1 and GIP responses were higher after the olive oil meal than after the butter meal. CONCLUSIONS: Olive oil induced lower triacylglycerol concentrations and higher HDL-cholesterol concentrations than butter, without eliciting differences in concentrations of glucose, insulin, or fatty acids. Furthermore, olive oil induced higher concentrations of GLP-1 and GIP than did butter, which may point to a relation between fatty acid composition, incretin responses, and triacylglycerol metabolism in the postprandial phase.

Adult↗

The effect of palm oil, lard, and puff-pastry margarine on postprandial lipid and hormone responses in normal-weight and obese young women.

Only a few studies have been published on the postprandial effects of different fatty acids in obese subjects. Therefore, the present study investigated the effects of three test meals containing palm oil (PO), lard (LD), or puff-pastry margarine (PPM), all normal dietary ingredients, on postprandial lipid and hormone responses in normal-weight and obese young women. The study was performed as a randomized, crossover design. The fats differed in the content of palmitic acid, stearic acid, and trans monounsaturated fatty acids allowing a dietary comparison of different 'solid' fatty acids. The obese women had significantly higher fasting concentrations and postprandial responses of plasma total triacylglycerol (TAG), chylomicron-TAG, and insulin compared with the normal-weight women but there was no significant difference in the postprandial responses between the three test meals. The obese women had fasting concentrations of leptin four times greater than the normal-weight women. There were no postprandial changes in the concentrations of leptin. The fasting concentrations of HDL-cholesterol were significantly lower in the obese women than in the normal-weight women, whereas there was no significant difference between the two groups in the concentrations of total cholesterol or LDL-cholesterol. These results provide evidence that obese women have exaggerated lipid and hormone responses compared with normal-weight women but the different contents of saturated and trans monounsaturated fatty acids provided by PO, LD, and PPM have no effect in either group.

Adult↗

[Saturated and monounsaturated fats in patients with insulin-dependent diabetes. Different effects on blood glucose and insulin response in NIDDM].

To compare the metabolic effect of co-ingestion of saturated and monounsaturated fat with potato, 12 NIDDM subjects received 300 g mashed potato alone or in combination with 40 g olive oil, 50 g butter or 100 g butter, respectively. Blood glucose response area to potatoes with 100 g butter (448 +/- 68 mmol/L x 240 min) was significantly lower than to the four other meals: 596 +/- 63 (potato alone), 649 +/- 82 (potato + 40 g olive oil), 587 +/- 80 (potato + 50 g butter), and 604 +/- 81 (potato + 80 g olive oil) mmol/L x 240 min, p < 0.05, respectively. The insulin response was significantly increased by adding 50 g and 100 g butter, whereas no effect after addition of 40 g and 80 g olive oil was found. The free fatty acid (FFA) level was higher when 100 g butter was added to the potato meal than without (0.67 +/- 0.05 vs 0.48 +/- 0.07 mmol/L, p < 0.05). The triglyceride response increased dose-dependently with the fat content of the meals irrespective of the type of fat. In conclusion butter increases the insulin response in patients with NIDDM more than olive oil, and large amounts also increase FFA and triglyceride levels.

Adult↗

Effect of 3-O-methylglucose on insulin secretion in the perfused dog and rat pancreas.

We recently reported that the nonmetabolizable glucose analogue, 3-O-methylglucose, stimulates somatostatin secretion in the perfused dog pancreas. In this study, we report that 3-O-methylglucose also stimulates insulin secretion in the dog pancreas. The effect was present at 5.5 mM glucose (p < 0.001) but not at O or 2.7 mM glucose. The inhibitor of glucose metabolism, mannoheptulose, blocked the insulinotropic action of 3-O-methylglucose. In contrast, 3-O-methylglucose had no effect on insulin secretion in the perfused rat pancreas. We conclude that 3-O-methylglucose stimulates insulin secretion in the dog and that the effect requires the presence of stimulatory concentrations of D-glucose.

3-O-Methylglucose↗

von Willebrand factor (vWf) as a plasma marker of endothelial activation in diabetes: improved reliability with parallel determination of the vWf propeptide (vWf:AgII).

Elevated plasma von Willebrand factor (vWf) levels are found in diabetes and other vasculopathies, and predict cardiovascular mortality. vWf is stored and released from endothelial cell secretory granules, along with equimolar amounts of its propeptide (vWf:AgII). In the present study, we examined plasma propeptide levels as a marker of endothelial secretion in vivo, using an ELISA based on monoclonal antibodies. vWf but not propeptide levels are influenced by blood groups, explaining in part the smaller variation in plasma propeptide levels among normal individuals. In both controls and insulin-dependent diabetic patients, we found a close correlation between propeptide and immunoreactive vWf levels (r2=0.54, p <0.0001). vWf and propeptide were elevated in patient subgroups with microalbuminuria or overt diabetic nephropathy, whereas only the propeptide was significantly elevated in the normoalbuminuric subgroup. This observation suggests that in conjunction with vWf, propeptide measurements may improve the identification of endothelial activation, which occurs frequently even without increased urinary albumin excretion. In 12 NIDDM patients, a 3-week diet enriched in monounsaturated fat (MUFA) resulted in parallel decreases in vWf (-22%, p <0.05) and propeptide (-17%, p <0.05) levels, indicating that the experimental diet affected endothelial secretion rather than vWf catabolism. A carbohydrate-enriched control diet did not significantly influence either marker. Our results suggest that concomitant determinations of plasma vWf and propeptide are useful tools to assess endothelial activation in vivo, and reinforce our previous conclusion that a diet rich in MUFA can improve endothelial function in NIDDM.

Adult↗

The day-to-day variation in insulin sensitivity in non-insulin-dependent diabetes mellitus patients assessed by the hyperinsulinemic-euglycemic clamp method.

The objective was to study the day-to-day variation in insulin sensitivity in non-insulin-dependent diabetes mellitus (NIDDM) and to analyze within- and between-person variances in the glucose infusion rate during steady state (M value). Ten NIDDM patients attending the outpatient clinic at Aarhus Amtssygehus were studied three times under standardized conditions. Each time, a 120-minute hyperinsulinemic-euglycemic clamp was performed. Similar M values were found on the 3 study days, with difference between M values on the 3 days of (mean +/- SD) 0.3 +/- 1.8 mg glucose/kg lean body mass (LBM)/min. The total coefficient of variation (CV) for M values was 57% after the first clamp, 55% after the second, and 53% after the third. Ninety percent of the total day-to-day variation in M values could be ascribed to between-person variation and 10% to within-person variation. Within-person components of variance included all sources of variation other than between-person variation. The within-person CV for M values was 11.9% +/- 7.2% after two clamp studies and 12.1% +/- 7.3% after three (P < .55). In conclusion, under standardized conditions, a valid estimate of insulin sensitivity assessed by the hyperinsulinemic-euglycemic clamp in NIDDM patients is obtained after a single measurement. Because of large between-person variation, paired data should be used when comparing insulin sensitivity in NIDDM patients.

Blood Glucose↗

A new look at dietary carbohydrate: chemistry, physiology and health. Paris Carbohydrate Group.

The current view of dietary carbohydrates as simply providing us with energy is outdated. Because of their varied chemistry and physical form the rate and extent to which the different types are digested in and absorbed from the small intestine varies. This in turn leads to affects on satiety, blood glucose and insulin, protein glycosylation, lipids and bile acids. Some carbohydrates reach the colon where they are fermented and affect many aspects of large bowel function, colonocyte and hepatic metabolism. A new framework for classifying and measuring food carbohydrates is needed to allow a greater understanding of the role of individual species in health and to inform the public of their importance. A classification based primarily on molecular size (degree of polymerisation) into sugars, oligosaccharides and polysaccharides, is suggested, with sub-groups identified by the nature of the monosaccharides. Greater knowledge of the chemical and physical properties of carbohydrates allow a more precise relation with physiology and health to be drawn. The Carbohydrate Group met in Paris in December 1995 at the invitation of Gerard Pascal, Director of CNERNA. Financial support for the meeting was provided by CNERNA.

Carbohydrates↗

Comparison of the effects of two weeks' intervention with different meal frequencies on glucose metabolism, insulin sensitivity and lipid levels in non-insulin-dependent diabetic patients.

AIMS: To compare the effects of 2 weeks on different meal frequencies on glucose metabolism, lipid levels and 24-hour blood pressure in non-insulin-dependent diabetic subjects. METHODS: Ten non-insulin-dependent diabetic outpatients from Aarhus City participated in a crossover study design. None were treated with insulin. The patients were randomly allocated to two isoenergetic diets either taken as three or eight meals per day for 2 weeks each. At the end of each period, the diurnal blood pressure and the responses to a test meal were measured. Furthermore, a hyperinsulinemic, euglycemic clamp was placed. RESULTS: Both the insulin sensitivity and 24-hour ambulatory blood pressure were similar as were the responses of glucose, insulin and free fatty acids to a carbohydrate-rich test meal at the end of the two diet periods. The HDL-cholesterol level was lowest in response to the 8-meal diet (p = 0.02). CONCLUSION: Increasing meal frequencies in a 2-week treatment period with weight-maintaining diets on an outpatient basis subdued the HDL-cholesterol levels but apparently had no impact on glucose metabolism or diurnal blood pressure in NIDDM subjects. These results give no indications of long-term beneficial effects of increasing the meal frequency in NIDDM patients.

Blood Glucose↗

Comparison of a carbohydrate-rich diet and diets rich in stearic or palmitic acid in NIDDM patients. Effects on lipids, glycemic control, and diurnal blood pressure.

OBJECTIVE: To compare the effects on lipid levels, glycemic control, and diurnal blood pressure of two diets rich in one of the two quantitatively most important saturated fatty acids, stearic and palmitic acid, with a carbohydrate-rich diet in NIDDM patients. RESEARCH DESIGN AND METHODS: A total of 15 NIDDM patients participated in a randomized crossover study with three 3-week diet interventions separated by 2-week washout periods. Patients started with a diet rich in stearic acid (44 E% [percent of total energy] fat [13 E% stearic acid], 40 E% carbohydrate, 15 E% protein), palmitic acid (45 E% fat [16 E% palmitic acid], 40 E% carbohydrate, 15 E% protein), or carbohydrate (29 E% fat, 51 E% carbohydrate, and 18 E% protein), then were shifted to the other two diets in a randomized block design. At the start and end of each intervention period, fasting blood samples were drawn for analysis of lipids and blood glucose. In addition, diurnal blood pressure was measured. RESULTS: At the end of the 3-week interventions, total cholesterol was significantly higher after the palmitic acid-rich diet than after the stearic acid-rich or carbohydrate-rich diets (5.3 +/- 1.3 vs. 5.0 +/- 1.2 and 4.9 +/- 1.2 mmol/l, respectively; P = 0.03). No significant differences in triglyceride, LDL, or HDL cholesterol levels were seen after the three intervention diets. No difference in effects between the diet periods were seen for fructosamine, HbA1c, fasting blood glucose, or diurnal blood pressure. CONCLUSIONS: For the first time, it has been demonstrated that a diet rich in palmitic acid was not as effective in lowering cholesterol levels as carbohydrate-rich and stearic acid-rich diets in NIDDM patients. No deleterious effects were seen on diurnal blood pressure, triglyceride levels, and glycemic control. Development of foods containing stearic acid rather than the more atherogenic saturated fatty acids may allow a wider choice of acceptable foods to NIDDM patients.

Adult↗

Endothelin-1 stimulates insulin secretion by direct action on the islets of Langerhans in mice.

Endothelin-1 (ET-1), a potent endothelium-derived vasoconstrictor peptide, is secreted in response to insulin. Elevated circulating ET-1 levels have been found in patients with diabetes mellitus and vascular dysfunction. The question arises whether ET-1 acts as a direct modulator of insulin secretion. To test this, we studied the effects of ET-1 on isolated mouse islets of Langerhans. ET-1 (1 nmol/l-1 mumol/l) dose-dependently stimulated insulin secretion from islets incubated in the presence of 16.7 mmol/l glucose (p < 0.05). The effect of ET-1 is glucose-dependent since no potentiation was found at 3.3 mmol/l glucose. Furthermore, ET-1 induced a large, transient increase in glucose-stimulated insulin secretion during islet perifusion in the presence (p < 0.001), but not in the absence, of extracellular Ca2+. The rate of 45Ca(2+)-efflux from 45Ca(2+)-prelabelled islets was transiently stimulated by ET-1 during perifusion at 16.7 mmol/l glucose in the presence of extracellular Ca2+ (p < 0.001). A short-lived increase in 45Ca(2+)-efflux was also observed in the absence of extracellular Ca2+ (p < 0.05). It is suggested that the effects of ET-1 on insulin secretion are critically dependent on influx via Ca(2+)-channels. In addition, ET-1 transiently enhanced 86Rb(+)-efflux from 86Rb(+)-prelabelled islets both in the presence (p < 0.001) and in the absence (p < 0.001) of extracellular Ca2+ suggesting that ET-1 does not elicit insulin secretion by inhibition of the potassium permeability. Our study provides evidence that ET-1 stimulates insulin secretion via a direct effect on the islets of Langerhans.

Analysis of Variance↗

Stimulation of somatostatin secretion by 3-O-methylglucose in the perfused dog pancreas.

CONCLUSION: 3-O-methylglucose stimulates somatostatin secretion from the dog pancreas by a glucose-dependent and glucose-like effect. Therefore, it is possible that 3-O-methylglucose-stimulated somatostatin secretion is dependent on glucose metabolism. BACKGROUND: Somatostatin secretion from the endocrine pancreas is stimulated by glucose, glyceraldehyde, and dihydroxyacetone but not affected by fructose, galactose, or ribose. Whether the nonmetabolizable glucose analog, 3-O-methylglucose affects somatostatin secretion is, however, not known. METHOD: We therefore, examined whether the glucose analog affects somatostatin secretion in the perfused dog pancreas. RESULTS: We found that when added to a medium containing 2.7 mM or 5.5 mM D-glucose, 3-O-methylglucose (10 mM) stimulated somatostatin secretion to the same extent as did an equivalent dose of D-glucose. The same stimulation was observed also with arginine at 2.5 mM in the perfusion medium. In contrast, 3-O-methylglucose did not stimulate somatostatin secretion in the absence of glucose in the perfusion medium. Mannoheptulose (5 mM), which inhibits glucose metabolism, completely blocked the secretion to both hexoses.

3-O-Methylglucose↗

The acute impact of ethanol on glucose, insulin, triacylglycerol,and free fatty acid responses and insulin sensitivity in type 2 diabetes.

The aim of the present study was to evaluate the acute effect of ethanol on insulin sensitivity, and glucose, insulin, free fatty acid (FFA), and triacylglycerol responses in ten patients with non-insulin-dependent (type 2) diabetes. In the test study an oral dose of 0.66 g ethanol/kg followed by continuous intravenous infusion of 0.1 g ethanol/kg per h was given to maintain a constant ethanol level in the blood. In the control study identical volumes of oral water and intravenous saline (9 g NaCl/l) were given. After 90 min insulin sensitivity was determined by the hyperinsulinaemic, euglycaemic clamp technique. Ethanol caused no change in blood glucose or insulin concentrations. The FFA level was suppressed by ethanol while the triacylglycerol level was unaffected. The insulin sensitivity was not affected by ethanol. No major acute effect of ethanol on the glycaemic control in fasting type 2 diabetic patients was found in comparison with what is seen in healthy people. The present study, along with the sparse literature, indicates that the ability of ethanol to induce hypoglycaemia is attenuated or absent in diet-treated type 2 diabetes. Furthermore, we found no change in insulin sensitivity. Consequently, the risk of acute ethanol-induced aberrations in carbohydrate metabolism in diet-treated type 2 diabetes seems to be less than previously expected, when alcohol is not taken as a part of a meal.

Administration, Oral↗

Differential effects of saturated and monounsaturated fat on blood glucose and insulin responses in subjects with non-insulin-dependent diabetes mellitus.

To compare the metabolic effect of coingestion of saturated and monounsaturated fats with potato, 12 subjects with non-insulin-dependent diabetes mellitus (NIDDM) received 300 g mashed potato alone or in combination with 40 g olive oil, 80 g olive oil, 50 g butter, or 100 g butter, respectively. The blood glucose response area to potatoes with 100 g butter (448 +/- 68 mmol.240 min/L) was significantly lower than after the four other meals: 596 +/- 63 (potato alone), 649 +/- 82 (potato + 40 g olive oil), 587 +/- 80 (potato + 50 g butter), and 604 +/- 81 (potato + 80 g olive oil) nmol.240 min/L, P < 0.05, respectively. The insulin response was significantly increased by adding 50 and 100 g butter, whereas addition of 40 and 80 g olive oil had no effect. The fatty acid concentration was higher when 100 g butter was added to the potato meal than when it was not (0.67 +/- 0.05 compared with 0.48 +/- 0.07 mmol/L, P < 0.05). Fatty acid concentrations were similar to those found for the other meals. The triacylglycerol response increased in a dose-dependent manner with the fat content of the meals irrespective of the type of fat. We conclude that butter increases the insulin response more than does olive oil, and large amounts of butter also increase fatty acid and triacylglycerol concentrations.

Adult↗

Influence of parboiling and physico-chemical characteristics of rice on the glycaemic index in non-insulin-dependent diabetic subjects.

OBJECTIVE: To study the influence of parboiling, amylose content and gelatinisation temperature of rice on the postprandial blood glucose and insulin responses in non-insulin-dependent diabetic (NIDDM) subjects. DESIGN AND SUBJECTS: Twelve NIDDM subjects ingested high (27%) and low amylose content five test meals of 50 g available carbohydrates as white bread, cooked polished rice with high (27%) and low amylose content (12%) with different gelatinisation temperature and as nonparboiled and parboiled. The meals were taken in random order after a 12h fast with approximately 7 days interval. RESULTS: The glycaemic indices (GI) of all rice varieties were lower than that of white bread (P <0.001). Furthermore, GI of parboiled rice with a high amylose content was lower than that of parboiled rice with a low amylose content (50 +/- 7 vs 73 +/- 7, P <0.01). No differences were 47 +/- 4, n.s.), nor between non-parboiled and parboiled rice (50 +/- 7 vs 53 +/- 7, n.s.). Insulin responses to the five test meals were not significantly different in the NIDDM subjects. CONCLUSIONS: In NIDDM subjects the investigated rices were all low glycaemic as compared to white bread,independent of parboiling and physico-chemical characteristics. The mildparboiling process used did not influence GI. The study showed that the amylose content, but not the gelatinisation temperature, may be an useful criterion in selection of low GI rices also after parboiling.

Aged↗

Effects of galanin on proinsulin mRNA and insulin biosynthesis in normal islets.

Whether the potent insulinostatic neuropeptide galanin also inhibits insulin production in normal islets is not known. Therefore, isolated mouse islets were incubated for 90 min in 2.8 or 16.7 mmol/l glucose and 3H-labelled leucine with addition of mouse galanin at 1, 10 or 100 nmol/l. Galanin potently inhibited glucose-stimulated insulin secretion at both 10 and 100 nmol/l (P < 0.05), and proinsulin biosynthesis was slightly inhibited at 100 nmol/l (P < 0.05). Also, mouse islets were incubated for 48 h at 5 or 16.7 mmol/l glucose with galanin at 1, 10 or 100 nmol/l and proinsulin mRNA was determined by hybridisation of extracted RNA with digoxigenin-labelled oligonucleotide insulin probe. Proinsulin mRNA levels were approximately doubled by glucose at 16.7 mmol/l compared at 5 mmol/l (P < 0.05). Galanin did not affect islet proinsulin mRNA levels. Therefore, galanin seems to mainly regulate insulin secretion without any important role in the regulation of insulin availability in normal islets.

Animals↗

[Favourable effect of olive oil in patients with non-insulin-dependent diabetes. The effect on blood pressure, blood glucose and lipid levels of a high-fat diet rich in monounsaturated fat compared with a carbohydrate-rich diet].

To compare blood pressure, glucose and fat metabolism after a high-fat diet rich in monounsaturated fat reduced day time systolic (131 +/- 3 vs. 137 +/- 3 mmHg, p < 0.04) and 24-hour systolic blood pressure (126 +/- 8 vs. 130 +/- 10 mmHg, p < 0.03) as well as day time diastolic (78 +/- 2 vs. 84 +/- 52 mmHg, p < 0.02) and diurnal diastolic blood pressure (75 +/- 6 vs. 78 +/- 5 mmHg, p < 0.03) as compared with the high-carbohydrate diet. Evidence of improved glucose tolerance on the high-monounsaturated diet compared with the high-carbohydrate diet were found with lower fasting blood glucose (6.1 +/- 0.3 vs. 6.8 +/- 0.5 mM, p < 0.05), lower average blood glucose levels (7.4 +/- 0.5 vs. 8.2 +/- 0.6 mmol/l, p < 0.01) and peak blood glucose responses (9.9 +/- 0.6 vs. 11.3 +/- 0.7 mmol/l, p < 0.02). Similar levels of fasting triglyceride, total cholesterol, LDL- and HDL cholesterol were found after the two diets.

Blood Glucose↗