Alexandra Bédard

Sex differences in the impact of the Mediterranean diet on cardiovascular risk profile

The traditional Mediterranean diet (MedDiet) is now widely recommended in the prevention of CVD. However, it is not known whether the MedDiet has the same beneficial cardiovascular effects in women and in men. The objective of the present study was to investigate sex-related differences with regard to changes in cardiometabolic variables in response to a 4-week isoenergetic MedDiet. Participants were thirty-eight men and thirty-two premenopausal women aged between 25 and 50 years who had slightly elevated LDL-cholesterol (LDL-C) concentrations (3·4-4·9 mmol/l) or total cholesterol:HDL-cholesterol ratio ≥ 5·0. A 4-week run-in period preceded the MedDiet in order to control the inter- and intra-individual variability. Cardiometabolic variables were measured before and after the MedDiet. Total cholesterol, LDL-C, apoB and apoA-1 plasma concentrations as well as diastolic blood pressure decreased (P < 0·05) in both men and women (respectively, 10, 10, 10, 6 and 5% for men and 6, 7, 9, 4 and 4% for women). ApoA-2 concentrations and insulin concentrations 2 h after the oral administration of 75 g of glucose demonstrated sex × time interactions (respectively, P = 0·05 and P = 0·03) and only men experienced a decrease for these variables (respectively, 8 and 25%). In conclusion, consuming a MedDiet led to significant changes in plasma lipid profile in both men and women, while only men had significant improvements in insulin homeostasis. These results support the importance of investigating sex-related differences in response to diet in order to perhaps further individualise dietary guidelines in the prevention of CVD and type 2 diabetes.

The Impact of Abdominal Obesity Status on Cardiovascular Response to the Mediterranean Diet

We investigated the impact of abdominal obesity status on the cardiovascular response to a fully controlled 4-week isoenergetic Mediterranean diet (MedDiet). Thirty-eight abdominally obese individuals (waist circumference >102 cm in men and >88 cm in women) and thirty-one nonabdominally obese individuals were recruited and studied before and after the MedDiet. All analyses were adjusted for the slight decrease in body weight, which occurred during the MedDiet (mean: 0.9 ± 1.2 kg). A group by time interaction was noted for waist circumference (P = 0.02), abdominally obese subjects showing a significant decrease and nonabdominally obese subjects a nonsignificant increase (resp., −1.1 and +0.3%). The MedDiet resulted in decreases in total cholesterol, LDL-C, HDL-C, apolipoprotein B, A-1, and A-2, total cholesterol/HDL-C ratio, LDL-C/HDL-C ratio, and systolic and diastolic blood pressure (time effect: P < 0.05). For all variables related to glucose/insulin homeostasis, no change was observed except for a decrease in 2 h glucose concentrations (time effect: P = 0.03). No group by time interaction was observed in any of the metabolic variables studied. Results from our study suggest that the adoption of the MedDiet leads to beneficial metabolic effects, irrespective of the abdominal obesity status.

Effects of juices enriched with xanthan and β-glucan on the glycemic response and satiety of healthy men

This study compared the effects of 3 palatable juices enriched with different polysaccharides with a control nonenriched juice on glucose and insulin responses as well as on appetite sensations and determined whether the polysaccharide-induced viscosity contributed to the effects of enriched juices on these variables. Using a randomized crossover design, 14 healthy male subjects consumed 4 juices: 3 juices were enriched with either xanthan gum, β-glucan, or a mix of xanthan gum and β-glucan, and the control juice had no added polysaccharides. Viscosity was measured at a shear rate of 30 s(-1), which represented an approximation of the viscosity in the gastrointestinal tract. One-sided tests were used in this study. Compared with the control juice, the juice supplemented with the mix of xanthan gum and β-glucan and the juice enriched with β-glucan alone led to a significant attenuation of the incremental peak of glucose (-0.8 mmol·L(-1), p = 0.001; and -0.5 mmol·L(-1), p = 0.03; respectively). However, no difference between juices was found for the incremental area under the curve for glucose, insulin, and appetite sensations. At 30 s(-1), only juices enriched with either the β-glucan/xanthan mixture or β-glucan alone yielded viscosity values higher than 0.1 Pa·s. These results highlight that the consumption of a palatable juice enriched with β-glucan alone or in mixture with xanthan gum reduces the glucose peak response compared with a juice with no added polysaccharides. The viscosity at a shear rate of 30 s(-1) seems to be linked to this effect.

Visceral adipose tissue accumulation and cardiovascular disease risk profile in postmenopausal women with impaired glucose tolerance or type 2 diabetes.

Objective  Women with impaired glucose tolerance (IGT) and type 2 diabetes (T2D) are more at risk of cardiovascular disease. The aim of this study was to test the hypothesis that increased visceral adipose tissue (VAT) could explain to a large extent alterations in the cardiovascular disease risk profile of postmenopausal women with IGT or T2D.

Effects of a dietary intervention promoting the adoption of a Mediterranean food pattern on fast-food consumption among healthy French-Canadian women.

It is expected that a dietary intervention based on the traditional Mediterranean food pattern should be associated with a reduction in fast-food consumption but this has never been tested before. We assessed the impact of a 12-week dietary intervention, promoting the adoption of a Mediterranean food pattern, on fast-food consumption among seventy-one healthy women aged between 30 and 65 years. The dietary intervention consisted of two group sessions and seven individual sessions with a dietitian. To determine the Mediterranean dietary score (MedScore) and fast-food consumption, an FFQ was administered. During the 12-week intervention, the MedScore significantly increased (from 21.1 (SD 3.6) units at baseline to 28.6 (SD 4.4) units at week 12, P < 0.0001), while the fast-food consumption significantly decreased (from 51.7 (SD 46.4) g/d at baseline to 20.5 (SD 18.2) g/d at week 12, P < 0.0001). Moreover, women who had a higher consumption of fast food at baseline decreased their fast-food consumption to the most (r - 0.50, P < 0.0001). When four subgroups were formed on the basis of median values of Medscore and fast-food consumption changes, it was found that only the subgroup of women which increased the most their MedScore and decreased the most their fast-food consumption experienced a significant decrease in BMI (P < 0.01). In conclusion, a dietary intervention promoting the Mediterranean food pattern led to a decrease in fast-food consumption among healthy women even if it was not a specific target of the intervention. Dietary strategies for increasing intake of healthy foods may be a useful approach for decreasing intake of less healthy foods.

Gender Differences in the Appetite Response to a Satiating Diet.

We examined gender differences in appetite sensations when exposed to Mediterranean diet (MedDiet) meals and determined whether there are gender differences in the change in the satiating properties of the MedDiet over time. Thirty-eight men and 32 premenopausal women consumed a 4-week isoenergetic MedDiet under controlled conditions. Visual analogue scales were used to measure perceived appetite sensations before and immediately after each meal consumed over the course of one day (Wednesday) of the first and the fourth week of intervention. Women reported greater decreases for desire to eat, hunger, and appetite score than men in response to the consumption of the MedDiet meals (gender-by-meal interactions, resp., P = 0.04, P = 0.048, and P = 0.03). Fullness and prospective food consumption responses did not significantly differ between men and women. Between the first and the fourth week of intervention, premeal prospective food consumption increased with time in men (P = 0.0007) but not in women (P = 0.84; P for gender-by-time interaction = 0.04). These results indicate gender differences in appetite sensations when exposed to the MedDiet. These results may be useful in order to have a better understanding of gender issues for body weight management.

Sex-related differences in the effects of the mediterranean diet on glucose and insulin homeostasis.

Objective. To document sex differences in the impact of the Mediterranean diet (MedDiet) on glucose/insulin homeostasis and to verify whether these sex-related effects were associated with changes in nonesterified fatty acids (NEFA). Methods. All foods were provided to 38 men and 32 premenopausal women (24–53 y) during 4 weeks. Variables were measured during a 180 min OGTT before and after the MedDiet. Results. A sex-by-time interaction for plasma insulin iAUC was found (men: −17.8%, P = 0.02; women: +9.4%, P = 0.63; P for sex-by-time interaction = 0.005). A sex-by-time interaction was also observed for insulin sensitivity (Cederholm index, P = 0.03), for which only men experienced improvements (men: +8.1%, P = 0.047; women: −5.9%, P = 0.94). No sex difference was observed for glucose and C-peptide responses. Trends toward a decrease in NEFA AUC (P = 0.06) and an increase in NEFA suppression rate (P = 0.06) were noted, with no sex difference. Changes in NEFA were not associated with change in insulin sensitivity. Conclusions. Results suggest that the more favorable changes in glucose/insulin homeostasis observed in men compared to women in response to the MedDiet are not explained by sex differences in NEFA response. This clinical trial is registered with clinicaltrials.gov NCT01293344.

Sex Differences in the Impact of the Mediterranean Diet on LDL Particle Size Distribution and Oxidation

Sex differences have been previously highlighted in the cardioprotective effects of the Mediterranean diet (MedDiet). The objective of this study was to investigate whether sex differences also exist with regard to LDL particle size distribution and oxidation. Participants were 37 men and 32 premenopausal women (24–53 years) with slightly elevated LDL-C concentrations (3.4–4.9 mmol/L) or total cholesterol/HDL-C ≥5.0. Variables were measured before and after a four-week isoenergetic MedDiet. Sex differences were found in response to the MedDiet for the proportion of medium LDL (255–260 Å) (p for sex-by-time interaction = 0.01) and small, dense LDL (sdLDL; <255 Å) (trend; p for sex-by-time interaction = 0.06), men experiencing an increase in the proportion of medium LDL with a concomitant reduction in the proportion of sdLDL, while an opposite trend was observed in women. A sex difference was also noted for estimated cholesterol concentrations among sdLDL (p for sex-by-time interaction = 0.03), with only men experiencing a reduction in response to the MedDiet. The MedDiet marginally reduced oxidized LDL (oxLDL) concentrations (p = 0.07), with no sex difference. Results suggest that short-termconsumption of the MedDiet leads to a favorable redistribution of LDL subclasses from smaller to larger LDL only in men. These results highlight the importance of considering sex issues in cardiovascular benefits of the MedDiet.

Sex Differences in the Effects of Repeated Taste Exposure to the Mediterranean Diet: A 6-month Follow-up Study

PURPOSE To determine whether an intervention based mainly on exposure to the Mediterranean diet (MedDiet), along with recommendations and tools for encouraging healthy eating, lead to different effects on dietary adherence and body weight management six months post-intervention in Canadian men and women. METHODS Thirty-eight males and 32 premenopausal females (all aged 24-53 years) were exposed to the same 4-week experimental MedDiet during which all foods were provided to participants. Participants also received some recommendations and tools to adhere to a healthy way of eating, with no other contact until the 6-month follow-up visit. RESULTS Compared with baseline, the Mediterranean score (MedScore) increased at the end of the 6-month follow-up (time effect P = 0.003), with no sex difference (sex-by-time interaction P = 0.97). With regard to MedScore components, sex differences were observed with males reporting changes in more dietary food groups than females. Although the intervention was not focused on body weight management, compared with baseline, BMI decreased during the intervention in both males and females; however, only females maintained the lower BMI 6 months after the intervention. CONCLUSIONS Exposure to the MedDiet for a short duration promotes the adherence to this food pattern in both sexes and helps in the management of body weight, especially in females.

Impact of Experimentally Induced Cognitive Dietary Restraint on Eating Behavior Traits, Appetite Sensations, and Markers of Stress during Energy Restriction in Overweight/Obese Women

Weight loss has been associated with changes in eating behaviors and appetite sensations that favor a regain in body weight. Since traditional weight loss approaches emphasize the importance of increasing cognitive dietary restraint (CDR) to achieve negative energy imbalance, it is difficult to untangle the respective contributions of energy restriction and increases in CDR on factors that can eventually lead to body weight regain. The present study aimed at comparing the effects of energy restriction alone or in combination with experimentally induced CDR on eating behavior traits, appetite sensations, and markers of stress in overweight and obese women. We hypothesized that the combination of energy restriction and induced CDR would lead to more prevalent food cravings, increased appetite sensations, and higher cortisol concentrations than when energy restriction is not coupled with induced CDR. A total of 60 premenopausal women (mean BMI: 32.0 kg/m2; mean age: 39.4 y) were provided with a low energy density diet corresponding to 85% of their energy needs during a 4-week fully controlled period. At the same time, women were randomized to either a condition inducing an increase in CDR (CDR+ group) or a condition in which CDR was not induced (CRD− group). Eating behavior traits (Three-Factor Eating Questionnaire and Food Craving Questionnaire), appetite sensations (after standardized breakfast), and markers of stress (Perceived Stress Scale; postawakening salivary cortisol) were measured before (T = 0 week) and after (T = 4 weeks) the 4-week energy restriction, as well as 3 months later. There was an increase in CDR in the CDR+ group while no such change was observed in the CDR− group (p=0.0037). No between-group differences were observed for disinhibition, hunger, cravings, appetite sensations, perceived stress, and cortisol concentrations. These results suggest that a slight increase in CDR has no negative impact on factors regulating energy balance in the context of energy restriction.