The effect of moderate intensity exercise in the postprandial period on the inflammatory response to a high-fat meal: an experimental study

Saturated Fatty Acids Consumed in Smoothies Increase Glucose and Metabolic Load Index in Young Adults Compared to Polyunsaturated Omega-3-Fatty Acids

Introduction: Chronic diets high in saturated fat (SF) and omega-6-fatty acids (O6FAs) elevate fasting triglycerides (TRGs) and glucose (GLU). Postprandial TRGs, GLU, and Metabolic Load Index (MLI) are better predictors of disease risk compared to fasting levels alone. Conversely, diets high in omega-3 fatty acids (O3FAs) may be cardioprotective. Unfortunately, many existing postprandial studies are not standardized to body weight and given in an amount individuals would typically consume in their daily lives; the MLI is not calculated, and varying types of fat content are not examined. Therefore, we sought to determine whether SF, O3FAs, or O6FAs altered postprandial TRGs, GLU, and MLI from a standardized mixed meal. Methods: Fifteen individuals (6 M and 9 F) visited the laboratory three times, separated by at least 48 h, to consume HFM smoothies with varying FA composition (SF, high O6FAs, and high O3FAs). The smoothies were standardized to 12 kcal/kg body weight, 63% total fat, and 0.72 g/kg sugar. TRGs and GLU were collected at baseline and at 2 h and 4 h postprandially; the MLI was calculated by summing the TRG and GLU responses at each time point. Results: There was a significant increase in TRGs across time points (p < 0.001). For TRGs, there was a trend toward a significant interaction between smoothie type and time (p = 0.06) due to the increase in TRGs in the SF compared to the O3FA smoothie. There was an increase in postprandial GLU that varied across smoothie types (p = 0.036). Taken together, the MLI was elevated in the SF smoothie compared to the O3FAs at 2 h (p = 0.041). Conclusion: A SF smoothie in the morning elevated the metabolic load compared to an O3FA smoothie. Mechanisms of action in the competing clearance of TRGs and GLU warrant further investigation.

Acute Exercise and the Systemic and Airway Inflammatory Response to a High-Fat Meal in Young and Older Adults

The purpose of the present study was to determine fasting and high-fat meal (HFM)-induced post-prandial systemic inflammation and airway inflammation (exhaled nitric oxide (eNO)) in older adults (OAs) compared to younger adults (YAs) before and after acute exercise. Twelve YAs (23.3 ± 3.9 y n = 5 M/7 F) and 12 OAs (67.7 ± 6 y, n = 8 M/4 F) completed two HFM challenges. After an overnight fast, participants underwent an HFM session or pre-prandial exercise (EX, 65% VO2Peak to expend 75% of the caloric content of the HFM) plus HFM (EX + HFM) in a randomized order. Systemic inflammatory cytokines were collected at 0, 3, and 6 h, while eNO was determined at 0, 2, and 4 h after the HFM (12 kcal/kg body weight: 61% fat, 35% CHO, 4% PRO). TNF-α was higher in OAs compared to YAs (p = 0.005) and decreased across time from baseline to 6 h post-HFM (p = 0.007). In response to the HFM, IL-6 decreased from 0 to 3 h but increased at 6 h regardless of age or exercise (p = 0.018). IL-8 or IL-1β did not change over the HFM by age or exercise (p > 0.05). eNO was also elevated in OAs compared to YAs (p = 0.003) but was not altered by exercise (p = 0.108). There was a trend, however, towards significance post-prandially in OAs and YAs from 0 to 2 h (p = 0.072). TNF-α and eNO are higher in OAs compared to YAs but are not elevated more in OAs post-prandially compared to YAs. Primary systemic inflammatory cytokines and eNO were not modified by acute exercise prior to an HFM.

Exercise to lower postprandial lipemia: why, when, what and how

We review recent findings on the ability of exercise to lower postprandial lipemia (PPL). Specifically, we answer why exercise is important in lowering PPL, when it is most effective to exercise to achieve this, what the preferred exercise is and how exercise reduces PPL. Most findings confirm the power of exercise to lower PPL, which is an independent risk factor for cardiovascular disease. Exercise is most effective when performed on the day preceding a high- or moderate-fat meal. This effect lasts up to approximately two days; therefore, one should exercise frequently to maintain this benefit. However, the time of exercise relative to a meal is not that important in real-life conditions, since one consumes several meals during the day; thus, an exercise bout will inevitably exert its lowering effect on PPL in one or more of the subsequent meals. Although moderate-intensity continuous exercise, high-intensity intermittent exercise (HIIE), resistance exercise and accumulation of short bouts of exercise throughout the day are all effective in lowering PPL, submaximal, high-volume interval exercise seems to be superior, provided it is tolerable. Finally, exercise reduces PPL by both lowering the rate of appearance and increasing the clearance of triacylglycerol-rich lipoproteins from the circulation.

Acute exercise improves glucose and TAG metabolism in young and older adults following high-fat, high-carbohydrate meal intake

A single high-fat, high-carbohydrate meal (HFHC) results in elevated postprandial glucose (GLU), triglycerides (TAG) and metabolic load index (MLI; TAG (mg/dl) + GLU (mg/dl)) that contributes to chronic disease risk. While disease risk is higher in older adults (OA) compared to younger adults (YA), the acute effects of exercise on these outcomes in OA is understudied. Twelve YA (age 23.3 ± 3.9 yrs, n = 5 M/7 F) and 12 OA (age 67·7 ± 6.0 yrs, n = 8 M/4 F) visited the laboratory in random order to complete a HFHC with no exercise (NE) or acute exercise (EX) condition. EX was performed 12 hours prior to HFHC at an intensity of 65 % of maximal heart rate to expend 75 % of the kcals consumed in HFHC (Marie Callender's Chocolate Satin Pie; 12 kcal/kgbw; 57 % fat, 37 % CHO). Blood samples were taken at 0, 30, 60, 90 minutes, and then every hour until 6 hours post-meal. TAG levels increased to a larger magnitude in OA (Δ∼61 ± 31 %) compared to YA (Δ∼37 ± 34 %, P < 0·001), which were attenuated in EX compared to NE (P < 0·05) independent of age. There was no difference in GLU between OA and YA after the HFM, however, EX had attenuated GLU independent of age (NE: Δ∼21 ± 26 %; EX: Δ∼12 ± 18 %, P = 0·027). MLI was significantly lower after EX compared to NE in OA and YA (P < 0·001). Pre-prandial EX reduced TAG, GLU and MLI post-HFHC independent of age.

Who would benefit most from postprandial lipid screening?

BACKGROUND & AIMS

Individuals with fasting triglycerides (TG) <150 mg/dL can experience a deleterious postprandial TG response ≥220 mg/dL to a high-fat meal (HFM). The purpose of this study was to identify individuals based on fasting TG that would benefit most from additional postprandial screening.

METHODS

We conducted a secondary analysis of 7 studies from our laboratories featuring 156 disease-free participants (64 M, 92 F; age 18-70 years; BMI 18.5-30 kg/m²). Participants observed a 10-12 h overnight fast, after which they consumed an HFM (10-13 kcal/kg body mass; 61-64% kcal from fat). Two methods were used to identify lower and upper fasting TG cut points. Method 1 identified the lower limit as the TG concentration at which ≥90% of individuals presented peak postprandial TG (PPTG) <220 mg/dL and the upper limit as the concentration which ≥90% of individuals presented PPTG ≥220 mg/dL. Method 2 utilized receiver operating characteristic (ROC) curves and identified the lower limit as the fasting TG concentration where sensitivity was ≈95% and the upper limit as the concentration at which specificity was ≈95%.

RESULTS

In Method 1, 90% of individuals with fasting TG >130 mg/dL (>1.50 mmol/L) exhibited PPTG ≥220 mg/dL (≥2.50 mmol/L), while 100% of individuals with fasting TG <66 mg/dL (0.75 mmol/L) had PPTG that did not exceed 220 mg/dL (2.50 mmol/L). In Method 2, when sensitivity was ≈95%, the corresponding fasting TG concentration was 70 mg/dL (0.79 mmol/L). When specificity was ≈95%, the corresponding fasting TG concentration was 114 mg/dL (1.29 mmol/L). Based on methods 1 and 2, there was a moderate positive association (r = 0.37, p < 0.004) between fasting and PPTG for individuals with fasting TG between 70 and 130 mg/dL (0.79-1.50 mmol/L), in which 24% exhibited PPTG ≥220 mg/dL (≥2.50 mmol/L) while 76% did not.

CONCLUSIONS

Postprandial TG testing is likely most useful for individuals with fasting TG concentrations between 70 and 130 mg/dL (0.79-1.50 mmol/L). Outside of this range, postprandial TG responses are largely predictable. Establishing a specific patient group for which postprandial TG testing is most useful may lead to earlier risk detection in these individuals.

Deep inspirations attenuate postprandial airway inflammation in college-aged adults with elevated baseline exhaled nitric oxide: A pilot study

Airway inflammation (assessed by exhaled nitric oxide (eNO)) increases after a single high-fat meal (HFM), yet this response may be modified by airway stretch and baseline eNO level.Purpose: The purpose of this study was to investigate whether deep inspirations (DIs) would attenuate airway inflammation post-HFM and whether this is modulated by baseline eNO level.Methods: A total of sixteen healthy college-aged participants completed a randomized cross-over study with 8 lower eNO (14.8 ± 2.0 ppb: 3 M/5F; age: 22.0 ± 2.2 yrs) and 8 higher eNO (29.3 ± 11.6 ppb 5 M/3F; age: 22.5 ± 2.6 yrs) participants. All participants completed a control (CON) condition (no DIs pre-HFM) and DI condition (60 DI's to total lung capacity immediately pre-HFM) after an overnight fast. The primary outcome was eNO. Participants had 20 minutes to consume the HFM (1 g fat/1 kg body weight) and eNO was performed at 2- and 4- hours post-HFM. To determine whether baseline eNO levels impacted the effect of DI's, a median split was performed on their baseline eNO level.Results: There was a significant increase in eNO as a main effect of time (p < 0.001). However when analyzing the potential effect of baseline eNO, there was no significant increase in eNO post-HFM in the higher eNO group in the DI condition (p = 0.54). DIs modified the eNO response to a HFM in the group with a higher baseline eNO value.Conclusions: These data display a possible bronchoprotective protect of DIs against postprandial airway inflammation in participants with higher initial eNO level.

Preceding exercise and postprandial hypertriglyceridemia: effects on lymphocyte cell DNA damage and vascular inflammation

Background

Exercise has proved effective in attenuating the unfavourable response normally associated with postprandial hypertriglyceridemia (PHTG) and accompanying oxidative stress. Yet, the acute effects of prior exercise and PHTG on DNA damage remains unknown. The purpose of this study was to examine if walking alters PHTG-induced oxidative damage and the interrelated inflammatory mechanisms.

Methods

Twelve apparently healthy, recreationally active, male participants (22.4 ± 4.1 years; 179.2 ± 6 cm; 84.2 ± 14.7 kg; 51.3 ± 8.6 ml·kg^− 1·min^− 1) completed a randomised, crossover study consisting of two trials: (1) a high-fat meal alone (resting control) or (2) a high-fat meal immediately following 1 h of moderate exercise (65% maximal heart rate). Venous blood samples were collected at baseline, immediately post-exercise or rest, as well as at 2, 4 and 6 h post-meal. Biomarkers of oxidative damage (DNA single-strand breaks, lipid peroxidation and free radical metabolism) and inflammation were determined using conventional biochemistry techniques.

Results

DNA damage, lipid peroxidation, free radical metabolism and triglycerides increased postprandially (main effect for time, p < 0.05), regardless of completing 1 h of preceding moderate intensity exercise. Plasma antioxidants (α-tocopherol and γ-tocopherol) also mobilised in response to the high-fat meal (main effect for time, p < 0.05), but no changes were detected for retinol-binding protein-4.

Conclusion

The ingestion of a high fat meal induces postprandial oxidative stress, inflammation and a rise in DNA damage that remains unaltered by one hour of preceding exercise.

High-Fat Meal–Induced Changes in Markers of Inflammation and Angiogenesis in Healthy Adults Who Differ by Age and Physical Activity Level

Background

Inflammation and angiogenesis are key facets of cardiovascular disease pathophysiology. Age and physical activity level can influence fasting systemic inflammation, but the impact of these factors on postprandial inflammation is unknown. In addition, markers of angiogenesis have never been tested in the context of a single high-fat meal (HFM).

Objective

The purpose of this study was to investigate the effects of an HFM on markers of inflammation and angiogenesis in individuals of different ages and physical activity levels.

Methods

Twenty-two healthy adults—8 younger active (YA) adults (4 men, 4 women; mean ± SD age: 25 ± 5 y), 8 older active (OA) adults (4 men, 4 women; 67 ± 5 y), and 6 older inactive (OI) adults (3 men, 3 women; 68 ± 7 y)—consumed an HFM [63% fat (39% saturated fat, 14% monounsaturated fat, 10% polyunsaturated fat), 34% carbohydrate; 12 kcal/kg body mass; 927 ± 154 kcal]. Fourteen inflammatory and 9 angiogenic markers were measured at baseline and 3 and 6 h postmeal.

Results

Significant group effects were observed in interleukin (IL)-10 (YA > OA; P = 0.02), IL-23 (YA > OA; P = 0.02), tumor necrosis factor (TNF)-α (OA < OI; P = 0.04), and vascular endothelial growth factor (VEGF)-C (YA < OA; P = 0.001). IL-8, VEGF-A, VEGF-C, and heparin-binding epidermal growth factor–like growth factor significantly increased, whereas granulocyte-macrophage colony-stimulating factor, interferon-γ, IL-1β, IL-5, IL-10, IL-12, IL-13, IL-17A, IL-23, TNF-α, leptin, angiopoietin-2, and follistatin significantly decreased after HFM consumption (P’s < 0.05). Notably, VEGF-A and VEGF-C were significantly higher at 3 h [mean difference: 22.5 pg/mL (VEGF-A); 73.5 pg/mL (VEGF-C)] and 6 h postmeal [mean difference: 26.9 pg/mL (VEGF-A); 81.2 pg/mL (VEGF-C)].

Conclusions

A novel finding of this study was the robust increase in VEGF after an HFM. There were also group differences in several inflammatory markers (IL-10 and IL-23 greater in YA than OA, and TNF-α lower in OA than OI) that suggest a potential influence of age and physical activity level.

Meal-exercise challenge and physical activity reduction impact on immunity and inflammation (MERIIT trial)

BACKGROUND

The effect of a pre-exercise meal as countermeasure to exercise induced immunodepression is poorly known. Also, sedentary behavior is associated with increased cardiometabolic risk but studies on immune changes are lacking. Therefore, we aimed to assess: 1) the impact of a pre-exercise Mediterranean meal (MdM) compared with a fast-food type meal (FFM) on exercise-induced immunological changes and 2) the impact of an induced acute period of sedentary behavior on neuro-immune-endocrine status.

METHODS

/Design: This is a two steps clinical trial including: (a) randomized crossover clinical trial, comparing the effect a high-fat/low-nutrient dense meal, FFM, with an isoenergetic similar high-nutrient dense meal, MdM, in the immune response to an exercise challenge (EC) and (b) a pilot trial assessing the neuro-immune-endocrine change induced by acute decreasing by half the usual physical activity level.

RESULTS

A total of 46 participants (26 females), median aged 25 years were included. Of those 39-completed protocol, including overweight, physical active and inactive and participants with asthma. There were no differences in the EC between interventions. Dietary factors and physical activity were closely monitored during interventions and kept similar. During physical inactivity induction, 31% reached the target of 50% reduction in mean step number and 77% reached a 30% reduction.

CONCLUSION

The use of a pre-exercise meal to modulate immune response and the understanding of the immunological impact of physical inactivity might help to establish future recommendations on how to practice exercise in a safer way and to recognize the potential impact of inactivity.

Exercise and postprandial lipemia: effects on vascular health in inactive adults

BACKGROUND

There is evidence to suggest that postprandial lipemia are is linked to the impairment of endothelial function, which is characterized by an imbalance between the actions of vasodilators and vasoconstrictors. The aim of this study was to determine the effects of a 12-week high-intensity training (HIT) and moderate continuous training (MCT) protocol on postprandial lipemia, vascular function and arterial stiffness in inactive adults after high-fat meal (HFM) ingestion.

METHODS

A randomized clinical trial was conducted in 20 healthy, inactive adults (31.6 ± 7.1 years). Participants followed the two exercise protocols for 12 weeks. To induce a state of postprandial lipemia (PPL), all subjects received a HFM. Endothelial function was measured using flow-mediated vasodilation (FMD), normalized brachial artery FMD (nFMD), aortic pulse wave velocity (PWV) and augmentation index (AIx). Plasma total cholesterol, high-density lipoprotein cholesterol (HDL-c), triglycerides and glucose were also measured.

RESULTS

The effects of a HFM were evaluated in a fasted state and 60, 120, 180, and 240 min postprandially. A significant decrease in serum glucose between 0 min (fasted state) and 120 min postprandially was found in the HIT group (P = 0.035). Likewise, FMD (%) was significantly different between the fasted state and 60 min after a HFM in the HIT group (P = 0.042). The total cholesterol response expressed as area under curve (AUC)(0-240) was lower following HIT than following MCT, but no significant differences were observed (8%, P > 0.05). Similarly, triglycerides AUC(0-240) was also lower after HIT compared with MCT, which trended towards significance (24%, P = 0.076). The AUC(0-240) for the glucose response was significantly lower following HIT than MCT (10%, P = 0.008). FMD and nFMD AUC(0-240) were significantly higher following HIT than following MCT (46.9%, P = 0.021 and 67.3%, P = 0.009, respectively). PWV AUC(0-240) did not differ following between the two exercise groups (2.3%, P > 0.05).

CONCLUSIONS

Supervised exercise training mitigates endothelial dysfunction and glucose response induced by PPL. Exercise intensity plays an important role in these protective effects, and medium-term HIT may be more effective than MCT in reducing postprandial glucose levels and attenuating vascular impairment.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT02738385 Date of registration: April 14, 2016.

Postprandial Metabolic Responses Differ by Age Group and Physical Activity Level

OBJECTIVES

To compare the postprandial metabolic responses to a high-fat meal in healthy adults who differ by age and physical activity level.

DESIGN

Cross-sectional, quasi-experimental design.

SETTING

Physical Activity and Nutrition Clinical Research Consortium (PAN-CRC) at Kansas State University (Manhattan, KS, USA).

PARTICIPANTS

Twenty-two healthy adults: 8 younger active (YA) adults (4M/4W; 25 ± 5 yr), 8 older active (OA) adults (4M/4W; 67 ± 5 yr), and 6 older inactive (OI) adults (3M/3W; 68 ± 7 yr).

INTERVENTION

Following an overnight (10-hour) fast and having abstained from exercise for 2 days, participants consumed a high-fat meal (63% fat, 34% CHO; 12 kcal/kg body mass; 927 ± 154 kcal). To assess the metabolic response, blood draws were performed at baseline and each hour following the meal for 6 hours.

MEASUREMENTS

Fasting and postprandial triglycerides (TG), glucose, Total-C, and HDL-C were measured. Metabolic load index (MLI) and LDL-C were calculated.

RESULTS

There were significant group x time interactions for TG (p < 0.0001) and MLI (p = 0.004). The TG total area-under-the-curve (tAUC) response was significantly lower in YA (407.9 ± 115.1 mg/dL 6 hr) compared to OA (625.6 ± 169.0 mg/dL 6 hr; p = 0.02) and OI (961.2 ± 363.6 mg/dL 6 hr; p = 0.0002), while the OA group TG tAUC was lower than the OI group (p = 0.02). The TG peak was significantly lower in YA (90.5 ± 27.0 mg/dL) than OA (144.0 ± 42.2 mg/dL; p = 0.03) and OI (228.2 ± 96.1 mg/dL; p = 0.0003), and was lower in the OA group compared to the OI group (p = 0.03). Glucose was significantly lower 1 hour after the meal in YA (89.4 ± 10.1 mg/dL; p = 0.01) and OA (87.3 ± 22.3 mg/dL; p = 0.005) versus OI (110.7 ± 26.9 mg/dL). MLI tAUC was significantly lower in YA (936.8 ± 137.7 mg/dL 6 hr; p = 0.0007) and OA (1133.0 ± 207.4 mg/dL; p = 0.01) versus OI (1553.8 ± 394.3 mg/dL), with no difference (p = 0.14) between YA and OA groups. Total-C and LDL-C were generally lower in younger compared to older participants at baseline and throughout the postprandial period, while no group or time effects were evident in HDL-C.

CONCLUSION

Both physical activity status and aging appear to affect the postprandial metabolic, namely TG, response to a high-fat meal. These findings point to an inherently diminished metabolic capacity with aging, but suggest that physical activity may help minimize this decrement.

Oral spore-based probiotic supplementation was associated with reduced incidence of post-prandial dietary endotoxin, triglycerides, and disease risk biomarkers

AIM

To determine if 30-d of oral spore-based probiotic supplementation could reduce dietary endotoxemia.

METHODS

Apparently healthy men and women (n = 75) were screened for post-prandial dietary endotoxemia. Subjects whose serum endotoxin concentration increased by at least 5-fold from pre-meal levels at 5-h post-prandial were considered “responders” and were randomized to receive either placebo (rice flour) or a commercial spore-based probiotic supplement [Bacillus indicus (HU36), Bacillus subtilis (HU58), Bacillus coagulans, and Bacillus licheniformis, and Bacillus clausii] for 30-d. The dietary endotoxemia test was repeated at the conclusion of the supplementation period. Dietary endotoxin (LAL) and triglycerides (enzymatic) were measured using an automated chemistry analyzer. Serum disease risk biomarkers were measured using bead-based multiplex assays (Luminex and Milliplex) as secondary, exploratory measures.

RESULTS

Data were statistically analyzed using repeated measures ANOVA and a P < 0.05. We found that spore-based probiotic supplementation was associated with a 42% reduction in endotoxin (12.9 ± 3.5 vs 6.1 ± 2.6, P = 0.011) and 24% reduction in triglyceride (212 ± 28 vs 138 ± 12, P = 0.004) in the post-prandial period Placebo subjects presented with a 36% increase in endotoxin (10.3 ± 3.4 vs 15.4 ± 4.1, P = 0.011) and 5% decrease in triglycerides (191 ± 24 vs 186 ± 28, P = 0.004) over the same post-prandial period. We also found that spore-based probiotic supplementation was associated with significant post-prandial reductions in IL-12p70 (24.3 ± 2.2 vs 21.5 ± 1.7, P = 0.017) and IL-1β (1.9 ± 0.2 vs 1.6 ± 0.1, P = 0.020). Compared to placebo post supplementation, probiotic subject had less ghrelin (6.8 ± 0.4 vs 8.3 ± 1.1, P = 0.017) compared to placebo subjects.

CONCLUSION

The key findings of the present study is that oral spore-based probiotic supplementation reduced symptoms indicative of “leaky gut syndrome”.

Post-prandial systemic 8-isoprostane increases after consumption of moderate and high-fat meals in insufficiently active males

A single high-fat meal (HFM) leads to an increase in triglycerides and oxidative stress. Oxidative stress can be assessed via 8-isoprostane generation, which is associated with the development of asthma and cardiovascular disease. No previous research has investigated whether airway and systemic 8-isoprostane increases postprandially in nonasthmatic participants according to the energy and fat content of a meal. Our purpose was to assess airway and systemic 8-isoprostane after a HFM and a true-to-life moderate-fat meal (MFM). We hypothesized that airway and systemic 8-isoprostane would increase after a HFM and a MFM, with the greatest increase in the HFM condition. Eight nonasthmatic men (25.8±6.9years) completed the HFM and MFM trials in a randomized crossover design. After a 10-hour fast, participants consumed either a HFM (71.13kJ/kg body mass, 60% fat, 23% CHO) or a MFM (35.56kJ/kg body mass, 30% fat, 52% CHO). Exhaled breath condensate to assess airway 8-isoprostane was collected at baseline and at 3 and 6hours postmeal. Venous blood samples were collected at baseline and hourly until 6hours postmeal to assess triglycerides, and every 3hours for systemic 8-isoprostane. Airway 8-isoprostane responses were not significant as a main effect of time (P=.072), between conditions (P=.365), or between time and condition (P=.319) postmeal. Systemic 8-isoprostane increased over time (P<.001), but not between conditions (P=.124) or between time and condition (P=.649) postmeal. Triglyceride incremental area under the curve was different in the HFM compared to the MFM condition (P=.013). After a HFM and a MFM, 8-isoprostane increases systemically; however, airway 8-isoprostane does not change.

Consumption of a high-fat breakfast on consecutive days alters preclinical biomarkers for atherosclerosis

BACKGROUND/OBJECTIVES

Recent research has speculated that the risk of developing atherosclerosis is due to the accumulation of the effects of daily diet choices. The purpose of this study was to examine which of our previously identified preclinical disease risk biomarkers were further elevated when consuming a high-fat (644±50 kcal; 100% recommended dietary allowance for fat), high-calorie (1118±100 kcal; 70% daily caloric needs) breakfast on consecutive days. Young, normal weight females (N=7) participated in this study.

SUBJECTS/METHODS

Blood samples were taken premeal and hourly for 5-h postprandial. Serum biomarkers (C-peptide, eotaxin, gastric inhibitory polypeptide, granulocyte colony-stimulating factor (G-CSF), granulocyte-monocyte colony-stimulating factor (GM-CSF), insulin, leptin, monocyte chemoattractant protein 1, pancreatic polypeptide (PPY) and tumor necrosis factor-α), monocyte concentration, and adhesion molecule expression (CD11a, CD18 and CD54) were measured. Area under the curve was calculated for each outcome variable as a function of day and data were analyzed for significance.

RESULTS

We found significant (P<0.05) increases on Day 2 for: GM-CSF (+47%; P=0.041), G-CSF (+31%; P=0.012), PPY (+51%; P=0.049), total monocyte (+110%; P=0.043), pro-inflammatory (PI) monocyte (+60%; P=0.012), PI monocyte CD18 (+960%; P=0.003), PI monocyte CD11a (+230%; P=0.006), and PI monocyte CD54 (+208%; P=0.015).

CONCLUSIONS

To our knowledge, the present study is the first to report changes in selected biomarkers and monocytes following eating a high-fat, high-calorie breakfast on consecutive days in humans. More research is needed to determine how transient the observed changes are and what the long-term implications for disease risk are.

Postprandial lipemic and inflammatory responses to high-fat meals: a review of the roles of acute and chronic exercise

Postprandial lipemia is an independent risk factor for development of cardiovascular disease. Postprandial inflammation following the prolonged elevation of triglycerides occurring subsequent to ingestion of high-fat meals, provides a likely explanation for increased disease risk. Substantial evidence has shown that acute exercise is an effective modality for attenuation of postprandial lipemia following a high-fat meal. However, much of the evidence pertaining to exercise intensity, duration, and overall energy expenditure for reducing postprandial lipemia is inconsistent. The effects of these different exercise variables on postprandial inflammation is largely unknown. Long-term, frequent exercise, however, appears to effectively reduce systemic inflammation, especially in at-risk or diseased individuals. With regard to an acute postprandial response, without a recent bout of exercise, high levels of chronic exercise do not appear to reduce postprandial lipemia. This review summarizes the current literature on postprandial and inflammatory responses to high-fat meals, and the roles that both acute and chronic exercise play. This review may be valuable for health professionals who wish to provide evidence-based, pragmatic advice for reducing postprandial lipemia and cardiovascular disease risk for their patients. A brief review of proposed mechanisms explaining how high-fat meals may result in pro-inflammatory and pro-atherosclerotic environments is also included.

Does chronic physical activity level modify the airway inflammatory response to an acute bout of exercise in the postprandial period?

Recent studies have confirmed that a single high-fat meal (HFM) leads to increased airway inflammation. However, exercise is a natural anti-inflammatory and may modify postprandial airway inflammation. The postprandial airway inflammatory response is likely to be modified by chronic physical activity (PA) level. This study investigated whether chronic PA modifies the airway inflammatory response to an acute bout of exercise in the postprandial period in both insufficiently active and active subjects. Thirty-nine nonasthmatic subjects (20 active, 13 males/7 females) who exceeded PA guidelines (≥150 min moderate-vigorous PA/week) and 19 insufficiently active (6 males/13 females) underwent an incremental treadmill test to exhaustion to determine peak oxygen uptake. Subjects were then randomized to a condition (COND), either remaining sedentary (CON) or exercising (EX) post-HFM. Exercise was performed at the heart rate corresponding to 60% peak oxygen uptake on a treadmill for 1 h post-HFM (63% fat, 10 kcal/kg body weight). Blood lipids and exhaled nitric oxide (eNO: marker of airway inflammation) were measured at baseline and 2 h and 4 h post-HFM. Sputum differential cell counts were performed at baseline and 4 h post-HFM. The mean eNO response for all groups increased at 2 h post-HFM (∼6%) and returned to baseline by 4 h (p = 0.03). There was a time × COND interaction (p = 0.04), where EX had a greater eNO response at 4 h compared with CON. Sputum neutrophils increased at 4 h post-HFM (p < 0.05). These findings suggest that airway inflammation occurs after an HFM when exercise is performed in the postprandial period, regardless of habitual activity level.

Effects of thirty and sixty minutes of moderate-intensity aerobic exercise on postprandial lipemia and inflammation in overweight men: a randomized cross-over study

BACKGROUND

The transient rise in blood lipids following a high-fat meal (HFM), known as postprandial lipemia, is linked to systemic inflammation and cardiovascular disease, but can be blunted by exercise. However, minimal research has investigated the effects of realistic exercise bouts on postprandial lipemia and inflammation in at-risk individuals. The purpose of this study was to assess the effects of moderate-intensity aerobic exercise lasting 30 or 60 min performed the evening before a HFM, on postprandial lipemia and inflammation in overweight, insufficiently active men.

METHODS

In this randomized-crossover study, twelve participants remained sedentary (CON), or performed a brisk walk on a treadmill at 60 % VO2peak for either 30 min (EX-30) or 60 min (EX-60), after which they consumed a small snack (270 kcal) to partially replace exercise energy expenditure. Following a 12-h overnight fast, participants consumed a standard HFM (1 g fat/kg; 1 g CHO/kg; 1117.8 ± 117.0 kcal). Blood draws were performed at baseline (pre-HFM) and 1, 2, 4, 6, and 8 h post-HFM to assess glucose, insulin, lipids, and systemic inflammation.

RESULTS

There were no significant differences (p > 0.05) in fasting triglycerides between EX-60 (118.7 ± 68.3 mg/dL), CON (134.8 ± 66.2 mg/dL) or EX-30 (135.5 ± 85.4 mg/dL). There were no differences in peak, time-to-peak, total or incremental area-under-the-curve between trials for triglyceride response (p > 0.05). There was no significant main effect of time (p > 0.05) in IL-1ra, IL-4, IL-5, IL-6, IL-10 or TNF-α from baseline to 8 h post-HFM in any trial.

CONCLUSIONS

In summary, we found that in overweight, insufficiently active men, neither 30 nor 60 min of moderate-intensity exercise performed 12 h prior to a HFM attenuated postprandial lipemia or inflammation, which could potentially be explained by the partial caloric replacement of exercise energy expenditure.