Louise Mennen

Risks and safety of polyphenol consumption.

This article gives an overview of the potential hazards of polyphenol consumption, as reported during the round-table discussion at the 1st International Conference on Polyphenols and Health, held in Vichy, France, November 2003. Adverse effects of polyphenols have been evaluated primarily in experimental studies. It is known, for example, that certain polyphenols may have carcinogenic/genotoxic effects or may interfere with thyroid hormone biosynthesis. Isoflavones are of particular interest because of their estrogenic activity, for which beneficial as well as detrimental effects have been observed. Furthermore, consumption of polyphenols inhibits nonheme iron absorption and may lead to iron depletion in populations with marginal iron stores. Finally, polyphenols may interact with certain pharmaceutical agents and enhance their biologic effects. It is important to consider the doses at which these effects occur, in relation to the concentrations that naturally occur in the human body. Future studies evaluating either beneficial or adverse effects should therefore include relevant forms and doses of polyphenols and, before the development of fortified foods or supplements with pharmacologic doses, safety assessments of the applied doses should be performed.

Effects of Long-Term Daily Low-Dose Supplementation With Antioxidant Vitamins and Minerals on Structure and Function of Large Arteries

Objective—Limited data exist from randomized trials evaluating, noninvasively, the impact of antioxidant supplementation on vascular structure and function. Methods and Results—This is a substudy of the SU.VI.MAX Study, which is a randomized, double-blind, placebo-controlled, cardiovascular and cancer primary prevention trial. Eligible participants (free of symptomatic chronic diseases and apparently healthy) were randomly allocated to daily receive either a combination of antioxidants (120 mg vitamin C, 30 mg vitamin E, 6 mg beta carotene, 100 μg selenium, and 20 mg zinc) or placebo and followed-up over an average of 7.2±0.3 years. At the end-trial examination, the carotid ultrasound examination and carotid–femoral pulse-wave velocity (PWV) measurement were performed blindly in 1162 subjects aged older than 50 years and living in the Paris area. The percentage of subjects with carotid plaques was higher in the intervention group compared with the placebo group (35.2% versus 29.5%, P = 0.04). Common carotid intima-media thickness (mean±SD) was not different between the 2 groups (0.70±0.08 versus 0.70±0.08 mm, P = 0.38). Mean PWV tended to be lower (indicating less stiff aortic arteries) in the intervention group but the difference did not reach statistical significance (P = 0.13). Conclusion—These results suggest no beneficial effects of long-term daily low-dose supplementation of antioxidant vitamins and minerals on carotid atherosclerosis and arterial stiffness.

Contribution of snacks and meals in the diet of French adults: a diet-diary study

To investigate the relative contributions of meals and snacks in the daily intake of free-living humans, 54 French adults maintained food intake diaries for four 7-day periods. They recorded all food and fluid intakes mentioning whether, in their opinion, each intake event was a snack or a meal. The weekly food diaries also contained information on the circumstances of each event such as time and place, number of persons present, and affective states (hunger, satiety, etc.) before and after intake. On average, 2.7 meals and 1.3 snacks were consumed each day. Very few days included no snacking. Total daily energy and nutrient intake were not different between days with and days without snacks. Snacks differed from meals in several dimensions. Meals were about twice as large as snacks in energy and weight. Nutrient intake, in absolute values, was higher in meals. In proportions, however, snacks contained more CHO and less fat and proteins. Most foods were consumed in larger amounts in the context of meals but a few (sweets, cereal bars, biscuits, and sodas) were mostly consumed as snacks. Hunger was more intense before but less intense after meals than snacks. The satiety ratio was higher for snacks than meals. Time of day affected many intake parameters. For example, afternoon snacks exhibited a high satiety ratio for a modest intake. The present study describes the status of several potential determining factors at the time of snacks in humans, demonstrating a specific role for snacks, as opposed to meals, in the daily eating pattern of healthy adults.

Sociodemographic and Geographic Correlates of Meeting Current Recommendations for Physical Activity in Middle-Aged French Adults: the Supplémentation en Vitamines et Minéraux Antioxydants (SUVIMAX) Study

OBJECTIVEnWe evaluated the characteristics of French subjects meeting current public health recommendations for physical activity.nnnMETHODSnWe assessed leisure-time physical activity cross-sectionally in 7404 adults aged 45 to 68 years with applied logistic regression models.nnnRESULTSnMeeting the recommended physical activity levels was more likely in subjects aged 60 years and older and in women with higher education levels or living in rural areas and was less likely in smokers. No association was found with time spent watching television. The contribution of vigorous activity to total time spent being active was approximately 2 times higher in subjects meeting recommendations.nnnCONCLUSIONSnParticipation in some vigorous activity may be viewed as a facilitator to attain physical activity recommendations. Relationships with physical environment variables in Europe need further investigation.

Dietary supplementation with cis-9,trans-11 conjugated linoleic acid and aortic stiffness in overweight and obese adults

BACKGROUNDnAnimal studies suggest that dietary cis-9,trans-11 (c9,t11) conjugated linoleic acid (CLA) may inhibit or regress the development of atherosclerosis. The effect of CLA on atherosclerosis has not been assessed in humans.nnnOBJECTIVEnWe investigated the effect of c9,t11 CLA supplementation on aortic pulse wave velocity (a marker of atherosclerosis) and on cardiovascular risk factors in overweight and obese but otherwise apparently healthy subjects.nnnDESIGNnIn a double-blind, randomized, placebo-controlled, parallel-group trial, we randomly assigned 401 subjects, aged 40-70 y and with a body mass index (in kg/m(2)) > or = 25, to receive either 4 g CLA/d (2.5 g c9,t11 CLA/d and 0.6 g trans-10,cis-12 CLA/d) or placebo supplements for 6 mo. Aortic pulse wave velocity, blood pressure, anthropometric characteristics, and concentrations of fasting lipid, glucose, insulin, and C-reactive protein were measured before and after supplementation.nnnRESULTSnDuring the intervention, mean (+/-SE) pulse wave velocity did not change in the c9,t11 CLA group (Delta0.00 +/- 0.07) compared with the placebo group (Delta0.09 +/- 0.06). There was no effect of c9,t11 CLA supplementation on blood pressure, body composition, insulin resistance, or concentrations of lipid, glucose, and C-reactive protein.nnnCONCLUSIONnThis study does not support an antiatherosclerotic effect or an effect on cardiovascular risk factors of c9,t11 CLA. This trial was registered at www.clinicaltrials.gov as NCT00706745.

Factor VIIa Response to a Fat-Rich Meal Does Not Depend on Fatty Acid Composition

A fat-rich meal increases activated factor VII (FVIIa), but it is not clear whether this increase depends on the fatty acid composition of the meal. Therefore, we studied the FVIIa response to fat-rich meals with different fatty acid composition in a randomized controlled crossover trial and investigated whether this response is mediated by an increase in serum triglycerides. Elderly women (> 60 years, n=91) received on separate days four different fat-rich breakfasts (50 energy percent [en%] of fat) and a control breakfast (1.5 en% fat; crossover). The fat-rich breakfasts differed in fatty acid composition: one rich in palmitic acid (21.7 g), one in stearic acid (18.6 g), and the other two in linoleic and linolenic acid-one with a ratio 3:1 (12.5/3.9 g) and the other with a ratio of 15:1 (18.8/1.2 g). At 8 AM before the breakfast (fasting) and at 1 and 3 PM, blood samples were taken, in which FVIIa and serum triglycerides were measured. FVIIa response to the fat-rich meals ranged from 11.6 mU/mL (95% confidence interval: 8.3,14.9) on the stearic meal to 15.9 mU/mL (12.0,19.8) on the linoleic/linolenic 15:1 meal at 1 PM and from 14.9 mU/mL (10.6,19.2) to 21.1 mU/mL (16.6,25.6) for the same meals at 3 PM. The responses did not differ between the fat-rich meals. After the control breakfast, FVIIa decreased, with 6.3 mU/mL (3.9,8.7) at 1 PM and 8.7 mU/mL (6.3,11.1) at 3 PM. The triglyceride response was lower after both linoleic/linolenic rich breakfasts compared with the palmitic and stearic breakfast (P<.05) and was not associated with the FVIIa response at any of the blood sampling occasions. The results of this study show that the response of FVIIa to a fat-rich meal is independent of its fatty acid composition and is not mediated by serum triglycerides.

Évolution des apports en nutriments dans l’étude SU.VI.MAX (1995-2002)

Resume Le role des apports alimentaires dans le determinisme de maladies chroniques (cancers, maladies cardiovasculaires, diabete, obesite, osteoporose) rend leur surveillance indispensable. Le lancement en 2001 en France, du Programme National Nutrition Sante (PNNS), a renforce cette necessite. Cet article a pour objectif de decrire les apports en nutriments dans la cohorte SU.VI.MAX suivie pendant 8 ans (1995-2002). L’analyse des apports en macronutriments a montre entre 1995 et 2002, une diminution des apports energetiques totaux et une augmentation de la contribution aux AET des glucides totaux tandis que celle des lipides a diminue. Cependant, la contribution des glucides simples aux AET a augmente et la place accordee aux acides gras satures reste trop importante. Si les pourcentages de sujets dont les apports sont inferieurs a 2/3 des ANC en vitamine C, calcium, magnesium sont restes stables, ce n’est pas le cas pour les vitamines B6, B9 (uniquement pour les femmes), A et surtout E pour lesquels les pourcentages ont augmente.

Évolution de la consommation alimentaire dans l’étude SU.VI.MAX (1995-2002)

Resume La nutrition joue un role majeur dans le determinisme de nombreuses maladies chroniques. Dans ce contexte, le Programme National Nutrition Sante (PNNS, 2001) a pour objectif general l’amelioration de l’etat de sante de l’ensemble de la population, en agissant sur l’un de ses determinants majeurs, la nutrition. Cet article presente l’evolution entre 1995 et 2002, de la consommation alimentaire des participants a l’etude SU.VI.MAX, par categorie d’aliments, telles qu’elles ont ete definies dans les reperes de consommation du PNNS diffuses au grand public. Les analyses ont montre que cette population etait en regle generale eloignee des reperes de consommations PNNS. Seules les frequences de consommation de fruits et legumes et la consommation moyenne de matieres grasse ajoutees vont dans le sens d’une amelioration. Ces observations soulignent l’importance d’une telle initiative de sante publique en France.

Influence of Centrifugation Temperature on the Plasma Total Homocysteine Concentration

Increased plasma total homocysteine (tHcy) is a recognized risk factor for cardiovascular diseases (1)(2)(3). Recommendations for accurate measurement of tHcy concentrations include collecting fasting blood samples (4)(5) with the patient in a sitting position (6), placing the (EDTA) tubes directly on ice, and immediately centrifuging the samples (4). There are no recommendations on whether to use a refrigerated or a nonrefrigerated centrifuge. We compared the tHcy concentrations in samples centrifuged at 4 °C and at ambient temperature.nnWe studied 40 females (age range, 43–68 years) who participated in a side protocol of the SU.VI.MAX study (7). Two fasting venous blood samples were collected in EDTA Vacutainer Tubes (Becton Dickinson), which were not put on ice, but were centrifuged immediately for 15 min at 2000 g , one at 4 °C and the other at ambient temperature (∼20 …