Sweetener augmentation of serum triacylglycerol during a fat challenge test in humans

Effect of a moderate dose of fructose in solid foods on TAG, glucose and uric acid before and after a 1-month moderate sugar-feeding period

There are few data on the effects on TAG, glucose and uric acid of chronic consumption of a moderate dose of fructose in solid foods. Twenty-eight participants with prediabetes and/or obesity and overweight commenced the study (BMI 32·3 kg/m2, age 44·7 years, fasting glucose 5·3 (sd 0·89) mmol/l and 2-h glucose 6·6 (sd 1·8) mmol/l). Twenty-four men and women who completed the study consumed, in random order, two acute test meals of muffins sweetened with either fructose or sucrose. This was followed by 4-week chronic consumption of 42 g/d of either fructose or sucrose in low-fat muffins after which the two meal tests were repeated. The sugar type in the chronic feeding period was also randomised. Fasting TAG increased after chronic consumption of fructose by 0·31 (sd 0·37) mmol/l compared with sucrose in those participants with impaired fasting glucose (IFG)/impaired glucose tolerance (IGT) (P = 0·004). Total cholesterol (0·33 mmol/l), LDL-cholesterol (0·24 mmol/l) and HDL-cholesterol (0·08 mmol/l) increased significantly over the 1- month feeding period with no differences between muffin types. Fasting glucose was not different after 1 month of muffin consumption. Uric acid response was not different between the two sugar types either baseline or 1 month, and there were no differences between baseline and 1 month. The increase in fasting TAG in participants with IFG/IGT suggests the need for caution in people at increased risk of type 2 diabetes.

The Influence of Different Foods and Food Ingredients on Acute Postprandial Triglyceride Response: A Systematic Literature Review and Meta-Analysis of Randomized Controlled Trials

The use of postprandial triglyceride (ppTG) as a cardiovascular disease risk indicator has gained recent popularity. However, the influence of different foods or food ingredients on the ppTG response has not been comprehensively characterized. A systematic literature review and meta-analysis was conducted to assess the effects of foods or food ingredients on the ppTG response. PubMed, MEDLINE, Cochrane, and CINAHL databases were searched for relevant acute (<24-h) randomized controlled trials published up to September 2018. Based on our selection criteria, 179 relevant trials (366 comparisons) were identified and systematically compiled into distinct food or food ingredient categories. A ppTG-lowering effect was noted for soluble fiber (Hedges' giAUC = -0.72; 95% CI: -1.33, -0.11), sodium bicarbonate mineral water (Hedges' gAUC = -0.42; 95% CI: -0.79, -0.04), diacylglycerol oil (Hedges' giAUC = -0.38; 95% CI: -0.75, -0.00), and whey protein when it was contrasted with other proteins. The fats group showed significant but opposite effects depending on the outcome measure used (Hedges' giAUC = -0.32; 95% CI: -0.61, -0.03; and Hedges' gAUC = 0.16; 95% CI: 0.06, 0.26). Data for other important food groups (nuts, vegetables, and polyphenols) were also assessed but of limited availability. Assessing for oral fat tolerance test (OFTT) recommendation compliance, most trials were ≥4 h long but lacked a sufficiently high fat challenge. iAUC and AUC were more common measures of ppTG. Overall, our analyses indicate that the effects on ppTG by different food groups are diverse, largely influenced by the type of food or food ingredient within the same group. The type of ppTG measurement can also influence the response.

Metabolic effects of aspartame in adulthood: A systematic review and meta-analysis of randomized clinical trials

Data about harms or benefits associated with the consumption of aspartame, a nonnutritive sweetener worldwide consumed, are still controversial. This systematic review and meta-analysis of randomized controlled clinical trials aimed to assess the effect of aspartame consumption on metabolic parameters related to diabetes and obesity. The search was performed on Cochrane, LILACS, PubMed, SCOPUS, Web of Science databases, and on a gray literature using Open Grey, Google Scholar, and ProQuest Dissertations & Theses Global. Searches across all databases were conducted from the earliest available date up to April 13, 2016, without date and language restrictions. Pooled mean differences were calculated using a random or fixed-effects model for heterogeneous and homogenous studies, respectively. Twenty-nine articles were included in qualitative synthesis and twelve, presenting numeric results, were used in meta-analysis. Fasting blood glucose (mmol/L), insulin levels (μU/mL), total cholesterol (mmol/L), triglycerides concentrations (mmol/L), high-density lipoprotein cholesterol (mmol/L), body weight (kg), and energy intake (MJ) were considered as the main outcomes in subjects that consumed aspartame, and results were presented as mean difference; % confidence interval, range. Aspartame consumption was not associated with alterations on blood glucose levels compared to control (-0.03 mmol/L; 95% CI, -0.21 to 0.14) or to sucrose (0.31 mmol/L; 95% CI, -0.05 to 0.67) and on insulin levels compared to control (0.13 μU/mL; 95% CI, -0.69 to 0.95) or to sucrose (2.54 μU/mL; 95% CI, -6.29 to 11.37). Total cholesterol was not affected by aspartame consumption compared to control (-0.02 mmol/L; 95% CI, -0.31 to 0.27) or to sucrose (-0.24 mmol/L; 95% CI, -0.89 to 0.42). Triglycerides concentrations were not affected by aspartame consumption compared to control (0.00 mmol/L; 95% CI, -0.04 to 0.05) or to sucrose (0.00 mmol/L; 95% CI, -0.09 to 0.09). High-density lipoprotein cholesterol serum levels were higher on aspartame compared to control (-0.03 mmol/L; 95% CI, -0.06 to -0.01) and lower on aspartame compared to sucrose (0.05 mmol/L; 95% CI, 0.02 to 0.09). Body weight did not change after aspartame consumption compared to control (5.00 kg; 95% CI, -1.56 to 11.56) or to sucrose (3.78 kg; 95% CI, -2.18 to 9.74). Energy intake was not altered by aspartame consumption compared to control (-0.49 MJ; 95% CI, -1.21 to 0.22) or to sucrose (-0.17 MJ; 95% CI, -2.03 to 1.69). Data concerning effects of aspartame on main metabolic variables associated to diabetes and obesity do not support a beneficial related to its consumption.

Fructose acute effects on glucose, insulin, and triglyceride after a solid meal compared with sucralose and sucrose in a randomized crossover study

BACKGROUND

Fructose, which is a sweetener with a low glycemic index, has been shown to elevate postprandial triglyceride compared with glucose. There are limited data on the effect of fructose in a solid mixed meal containing starch and protein.

OBJECTIVE

We determined the effects of sucrose, fructose, and sucralose on triglyceride, glucose, and insulin in an acute study in healthy, overweight, and obese individuals.

DESIGN

The study had a randomized crossover design. Twenty-seven participants with a mean age of 44 y and a mean body mass index (in kg/m(2)) of 26 completed the study. Fructose (52 g), sucrose (65 g), and sucralose (0.1 g) were delivered as sweet-taste-balanced muffins with a total fat load (66 g). Blood samples were taken at baseline and every 30 min for 4-h glucose, triglyceride, and insulin concentrations, and the area under the curve (AUC) and the incremental area under the curve (iAUC) were analyzed.

RESULTS

No significant difference was shown between the 3 sweeteners for triglyceride and glucose concentrations and the AUC. The glucose iAUC was lower for fructose than for sucrose and sucralose (P < 0.05). Insulin concentrations differed significantly by the type of muffin (P = 0.001), the interaction of time by type of muffin (P = 0.035), the AUC (P < 0.001), and the iAUC (P < 0.001). Fructose had a significantly lower insulin response than that of either sucrose (P-treatment = 0.006) or sucralose (P-treatment = 0.041).

CONCLUSIONS

Fructose, at a moderate dose, did not significantly elevate triglyceride compared with sucrose or sucralose and lowered the glucose iAUC. These results indicate that these sweeteners, at an equivalent sweetness, can be used in normal solid meals. Fructose showed a lower insulin response, which may be beneficial in the long term in individuals at risk of type 2 diabetes. This trial was registered at the Australian New Zealand Clinical Trials Registry as ACTRN12615000279527.

Acute effects of feeding fructose, glucose and sucrose on blood lipid levels and systemic inflammation

Background

Recent studies have demonstrated a relationship between fructose consumption and risk of developing metabolic syndrome. Mechanisms by which dietary fructose mediates metabolic changes are poorly understood. This study compared the effects of fructose, glucose and sucrose consumption on post-postprandial lipemia and low grade inflammation measured as hs-CRP.

Methods

This was a randomized, single blinded, cross-over trial involving healthy subjects (n = 14). After an overnight fast, participants were given one of 3 different isocaloric drinks, containing 50 g of either fructose or glucose or sucrose dissolved in water. Blood samples were collected at baseline, 30, 60 and 120 minutes post intervention for the analysis of blood lipids, glucose, insulin and high sensitivity C-reactive protein (hs-CRP).

Results

Glucose and sucrose supplementation initially resulted in a significant increase in glucose and insulin levels compared to fructose supplementation and returned to near baseline values within 2 hours. Change in plasma cholesterol, LDL and HDL-cholesterol (measured as area under curve, AUC) was significantly higher when participants consumed fructose compared with glucose or sucrose (P < 0.05). AUC for plasma triglyceride levels however remained unchanged regardless of the dietary intervention. Change in AUC for hs-CRP was also significantly higher in subjects consuming fructose compared with those consuming glucose (P < 0.05), but not sucrose (P = 0.07).

Conclusion

This study demonstrates that fructose as a sole source of energy modulates plasma lipids and hsCRP levels in healthy individuals. The significance of increase in HDL-cholesterol with a concurrent increase in LDL-cholesterol and elevated hs-CRP levels remains to be delineated when considering health effects of feeding fructose-rich diets.

Registration number for clinical trials

ACTRN12614000431628

Evidence-based review on the effect of normal dietary consumption of fructose on blood lipids and body weight of overweight and obese individuals

Although some investigators have hypothesized that ingestion of fructose from foods and beverages is responsible for the development of hyperlipidemia or obesity, a recent evidence-based review demonstrated that there was no relationship between the consumption of fructose in a normal dietary manner and the development of hyperlipidemia or increased weight in normal weight individuals. Because overweight and obese individuals may exhibit metabolic abnormalities such as insulin resistance, impaired glucose tolerance, hyperlipedemia, and/or alterations in gut hormones involved in appetite regulation, the findings of fructose studies performed in normal weight subjects may not be particularly relevant for overweight or obese subjects. A systematic assessment of the strength and quality of the studies and their relevance for overweight or obese humans ingesting fructose in a normal dietary manner has not been performed. The purpose of this review was to critically evaluate the existing database for a causal relationship between the ingestion of fructose in a normal, dietary manner and the development of hyperlipidemia or increased body weight in overweight or obese humans, using an evidence-based approach. The results of the analysis indicate that there is no evidence which shows that the consumption of fructose at normal levels of intake causes biologically relevant changes in triglycerides (TG) or body weight in overweight or obese individuals.

Evidence-based review on the effect of normal dietary consumption of fructose on development of hyperlipidemia and obesity in healthy, normal weight individuals

In recent years, there has been episodic speculation that an increase in consumption of fructose from foods and beverages is an underlying factor responsible for the relatively recent increase in obesity and obesity-related diseases such as diabetes. Reports in support of this hypothesis have been published, showing that concentrations of triglycerides (TG) are higher and concentrations of insulin and hormones associated with satiety are lower in animals following the ingestion of fairly large quantities of fructose, compared to other carbohydrates. However, results from human studies are inconsistent. A possible reason for the inconsistent results is that they are dependent on the particular study population, the design of the studies, and/or the amount of fructose administered. A systematic assessment of the strength and quality of the studies and their relevance for healthy, normal weight humans ingesting fructose in a normal dietary manner has not been performed. The purpose of this review was to critically evaluate the existing database for a causal relationship between the ingestion of fructose in a normal, dietary manner and the development of hyperlipidemia or increased body weight in healthy, normal weight humans, using an evidence-based approach. The results of the analysis indicate that fructose does not cause biologically relevant changes in TG or body weight when consumed at levels approaching 95th percentile estimates of intake.

Oral Fat Exposure Pattern and Lipid Loading Effects on the Serum Triacylglycerol Concentration of Humans

Orosensory exposure to dietary fat elicits an early, transient spike (first phase; minutes 0-60) and augmented, more sustained postprandial (second phase; minutes 120-360) elevation of serum triacylglycerol (TAG) in humans. To assess the physiological significance of these effects, TAG concentrations were monitored following manipulation of the oral exposure pattern and accompanying lipid load. Fifteen healthy adults participated in a randomized, 6-arm, crossover design study. Conditions consisted of ingestion of 30-g loads of safflower oil, provided as capsules to bypass oral stimulation, followed by 15 min of oral stimulation (mastication and expectoration) with full-fat or nonfat cream cheese (conditions 1 and 2); the same oral load ingested intermittently with oral stimulation by both food forms (conditions 3 and 4); and 10-g lipid loads ingested with intermittent oral stimulation by both food forms (conditions 5 and 6). Blood was collected via an indwelling catheter and TAG was measured at minutes -15, 0, 10, 20, 30, 40, 50, 60, 120, 240, and 360 relative to the onset of sensory stimulation. Testing was conducted weekly. Sequential (lipid loading followed by oral stimulation) and intermittent (intermixed lipid loading and oral stimulation) conditions led to comparable TAG responses. Significant first- and second-phase TAG concentration increases were observed with the 30-g loads, but not the 10-g loads. TAG responses to the full-fat and nonfat stimuli were similar. These data support the veracity of the earlier literature based on sequential oral exposure regimens and indicate that TAG responses reflect an interaction between oral fat signaling and gut lipid content. The augmentation of TAG associated specifically with dietary fat exposure, as compared to a nonfat food matched on other sensory properties, may only occur with higher fat loads.

Acute fish oil and soy isoflavone supplementation increase postprandial serum (n-3) polyunsaturated fatty acids and isoflavones but do not affect triacylglycerols or biomarkers of oxidative stress in overweight and obese hypertriglyceridemic men

Chronic consumption of fish and fish oil high in (n-3) PUFA reduces triacylglycerols (TG) but may increase oxidative stress, whereas consumption of soy isoflavones may reduce oxidative stress. Elevated serum TG and oxidative stress are considered cardiovascular disease (CVD) risk factors, but the effects of acute (n-3) PUFA and soy isoflavones on these CVD risk factors are unknown. The purpose of the study was to determine the effects of acutely supplementing a high-fat, high-fructose meal with fish oil and isoflavone placebo (FO) and fish oil placebo and soy isoflavones (ISO). In a randomized, double-blind, placebo-controlled, crossover study, 10 overweight or obese men consumed a high-fat, high-fructose meal with 4 dietary supplement combinations: fish oil placebo and isoflavone placebo (placebo); fish oil and isoflavone placebo (FO); fish oil placebo and isoflavones (ISO); and fish oil and isoflavones (FO + ISO). Serum collected at baseline and at 2, 4, and 6 h postprandially was analyzed for fatty acids, isoflavones, TG, and oxidative stress biomarkers (lipid hydroperoxides, oxidized-LDL, total antioxidant status). FO significantly increased serum (n-3) PUFA and ISO increased serum isoflavones. The study meal significantly increased serum total fatty acids and TG without affecting oxidative stress biomarkers. Serum TG and oxidative stress biomarkers did not differ between treatments. The FO and ISO were bioavailable but did not attenuate the postprandial rise in serum TG. Neither the study meal nor the FO or ISO induced significant changes in oxidative stress biomarkers. The current study adds to a limited literature on the acute effects of FO and ISO interventions on postprandial biomarkers of CVD risk.

Aspartame: a safety evaluation based on current use levels, regulations, and toxicological and epidemiological studies

Aspartame is a methyl ester of a dipeptide used as a synthetic nonnutritive sweetener in over 90 countries worldwide in over 6000 products. The purpose of this investigation was to review the scientific literature on the absorption and metabolism, the current consumption levels worldwide, the toxicology, and recent epidemiological studies on aspartame. Current use levels of aspartame, even by high users in special subgroups, remains well below the U.S. Food and Drug Administration and European Food Safety Authority established acceptable daily intake levels of 50 and 40 mg/kg bw/day, respectively. Consumption of large doses of aspartame in a single bolus dose will have an effect on some biochemical parameters, including plasma amino acid levels and brain neurotransmitter levels. The rise in plasma levels of phenylalanine and aspartic acid following administration of aspartame at doses less than or equal to 50 mg/kg bw do not exceed those observed postprandially. Acute, subacute and chronic toxicity studies with aspartame, and its decomposition products, conducted in mice, rats, hamsters and dogs have consistently found no adverse effect of aspartame with doses up to at least 4000 mg/kg bw/day. Critical review of all carcinogenicity studies conducted on aspartame found no credible evidence that aspartame is carcinogenic. The data from the extensive investigations into the possibility of neurotoxic effects of aspartame, in general, do not support the hypothesis that aspartame in the human diet will affect nervous system function, learning or behavior. Epidemiological studies on aspartame include several case-control studies and one well-conducted prospective epidemiological study with a large cohort, in which the consumption of aspartame was measured. The studies provide no evidence to support an association between aspartame and cancer in any tissue. The weight of existing evidence is that aspartame is safe at current levels of consumption as a nonnutritive sweetener.

Addition of glucose to a fatty meal delays chylomicrons and suppresses VLDL in healthy subjects

BACKGROUND

Postprandial lipemia has been shown in a number of studies to be associated with atherosclerosis. However, the test meals used in these studies were heterogeneous particularly in their carbohydrate content, which may be important for the resulting lipemia and which makes comparison between different studies difficult. We studied the effect of 75 g glucose added to a fatty meal on various lipoproteins and on gastric emptying.

MATERIALS AND METHODS

Fourteen healthy young volunteers were studied in the fasting state and until 7 h postprandially. In a crossover design, each subject received an oral fat load (1 g fat kg(-1) body weight) with or without 75 g glucose. Triacylglycerol (TG) and free fatty acids (FFA) were then measured in whole blood and lipoproteins were separated off by ultracentrifuging. Gastric emptying was determined by the (13)C breath test.

RESULTS

The addition of 75 g glucose to a fatty meal had two different effects. Gastric emptying was delayed by about 2 h and the chylomicron response was consequently postponed. In addition, the postprandial increase in VLDL triacylglycerol was reduced by 40%, which may be due to the pronounced FFA depression during the glucose-induced rise in insulin.

CONCLUSIONS

75 g glucose added to an oral fat load causes a delay of the chylomicron response and a marked suppression of the postprandial increase in VLDL.

Oral stimulation influences postprandial triacylglycerol concentrations in humans: nutrient specificity

OBJECTIVE

To determined whether the nature of the lipid in an oral stimulus modifies postprandial triacylglycerolemia.

METHODS

Sixteen healthy adults (eight male, eight female) participated in six test sessions conducted weekly. The test sessions were administered randomly after overnight fasts and included: ingestion of 50 grams of butter in capsules (to avoid oral stimulation with lipids) and 500 mL of water in 15 minutes followed by oral stimulation with one of the following foods on a cracker: butter, unsaturated fatty acid (UFA) margarine, jelly, UFA margarine + jelly, cracker alone or no oral stimulation. Sensory stimulation entailed masticating and expectorating approximately 5.0 g samples of each stimulus every three minutes for 110 minutes. Blood was drawn immediately after preload ingestion and at minutes 35, 85, 200, 320, and 440 post loading and analyzed for serum triacylglycerol (TAG), insulin and glucose concentrations.

RESULTS

Only the oral samples containing the UFA margarine led to significant elevations of serum TAG concentration compared to baseline (p < 0.05). Maximum change of TAG concentrations were greater following orosensory stimulation with UFA margarine compared to orosensory stimulation with butter, jelly or UFA margarine + jelly. No differences were observed relative to vehicle alone or no orosensory stimulation, but this is due to lower nadir values for these treatments. Insulin and glucose concentrations were not different between treatments.

CONCLUSION

Oral exposure specifically to an unsaturated dietary lipid augments the postprandial rise of TAG, compared to baseline.