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Biomedical subjects

M Porrini

Publications and source records attributed to M Porrini.

At least 19 recordsLinked to original sources
PubMed2004

Bioavailability of carotenoids from spinach and tomatoes.

BACKGROUND AND AIM: Few published studies have described the bioavailability of the different carotenoids in spinach. This was designed to evaluate the effects on plasma carotenoid concentrations of a daily consumption of spinach (rich in lutein and beta-carotene), alone or together with lycopene-rich tomato puree. METHODS AND RESULTS: Nine healthy young women consumed a standard low-carotenoid diet during the pre-study phase, the spinach diet (standard diet plus 150 g spinach: 9 mg lutein, 4 mg beta-carotene) from day 0 to day 21, and then, after a wash-out period, the spinach-tomato diet (standard diet plus 150 g spinach and 25 g tomato puree: 9 mg lutein, 4.3 mg beta-carotene and 7 mg lycopene) from day 35 to day 56. The spinach and spinach-tomato supplements were consumed together with 10 g olive oil. Fasting blood samples were collected on day -7, and every week thereafter. Plasma carotenoid concentrations significantly decreased during the standard low-carotenoid diet. Lutein levels gradually increased after spinach consumption from 0.36+/-0.05 to 1.59+/-0.19 micromol/L (p<0.0001), decreased during the wash-out period from 1.59+/-0.19 to 0.62+/-0.07 micromol/L (p<0.001), and rose again after the intake of spinach-tomato puree from 0.62+/-0.07 to 1.55+/-0.17 micromol/L (p<0.0001). beta-carotene levels also increased during both dietary supplementation periods. Lycopene decreased during the spinach diet from 0.20+/-0.03 to 0.07+/-0.01 micromol/L (p<0.001) and increased during the spinach-tomato diet from 0.05+/-0.01 to 0.52+/-0.06 micromol/L (p<0.0001). CONCLUSIONS: The results of this study confirm that a regular intake of selected vegetables leads to a progressive increase in plasma carotenoid concentrations. The addition of tomato puree to spinach does not decrease lutein plasma concentrations. Furthermore, baseline plasma levels of lutein and lycopene are important variables affecting the relative increase in their levels after supplementation: ie more depleted subjects are expected to have a greater percent rise in plasma carotenoid concentrations.

Adult↗
PubMed2004

Lycopene and vitamin C concentrations increase in plasma and lymphocytes after tomato intake. Effects on cellular antioxidant protection.

OBJECTIVE: This study seeks to verify whether the regular consumption of small amounts of tomato products can protect lymphocyte DNA and lipids from oxidative damage. DESIGN: Standardized dietary intervention. SUBJECTS: Twelve healthy female subjects (mean age 25.2 y). INTERVENTION: Subjects were instructed to follow a standardized diet for 1 week, followed by 3 weeks consumption of the same diet enriched with small amounts of different tomato products providing as a mean 8 mg lycopene, 0.5 mg beta-carotene and 11 mg vitamin C per day. Plasma and lymphocyte concentrations of carotenoids, vitamin C and vitamin E were analysed. Ex vivo protection of lymphocyte DNA from oxidative injury produced by iron ions was evaluated by means of the Comet assay, and lipid peroxidation by HPLC analysis of malondialdehyde (MDA). RESULTS: Dietary intervention with tomato products increased lycopene concentration both in plasma (P < 0.001) and lymphocytes (P < 0.01). Vitamin C concentrations increased by approximately 35% in plasma (P < 0.05) and by approximately 230% in lymphocytes (P < 0.005). Vitamin E decreased significantly in plasma (P < 0.0001) but not in lymphocytes. Finally, there was an improved protection from DNA oxidative damage (P < 0.05) with no significant effect on MDA levels. CONCLUSIONS: Our results suggest that tomato products are not only good sources of lycopene but also sources of bioavailable vitamin C. A Regular intake of small amounts of tomato products can increase cell protection from DNA damage induced by oxidant species. This effect may originate from the synergism of different antioxidants present in tomatoes.

Administration, Oral↗
PubMed2000

Tomato consumption does not affect the total antioxidant capacity of plasma.

This study was performed to evaluate the effect of tomato intake on total antioxidant activity of plasma measured by the radical trapping antioxidant parameter assay in 11 healthy female subjects. After 7 d of a diet low in carotenoids and free from lycopene, subjects ate 25 g tomato puree daily (containing 7.0 mg lycopene and 0.25 mg beta-carotene) for 14 consecutive days. At the beginning and end of tomato supplementation, the carotenoid plasma concentration and the total antioxidant activity of plasma were assessed. Before tomato puree consumption, mean +/- SE total lycopene and beta-carotene plasma concentrations were 0.13 +/- 0.02 micromol/L and 0.24 +/- 0.04 micromol/L, respectively. After tomato puree supplementation, both concentrations increased significantly (0.57 +/- 0.06 micromol/L, P < 0.0001 for total lycopene, and 0.31 +/- 0. 04 micromol/L, P = 0.0036 for beta-carotene); however, total plasma antioxidant capacity values did not change significantly. From our results, intake of a food rich in carotenoids does not seem to modify the antioxidant capacity of plasma as evaluated by the radical trapping antioxidant parameter assay.

Adult↗
PubMed2000

The physical state of a meal affects hormone release and postprandial thermogenesis.

There is evidence that food consistency may influence postprandial physiological responses. Recently we found that homogenization of a vegetable-rich meal significantly delayed the gastric emptying rate and was more satiating than the same meal in solid-liquid form. In this present study we investigated whether homogenization also influences endocrine and metabolic responses to the meal. Eight healthy men, aged 21-28 (mean 24.5) years, were given the meal (cooked vegetables 250 g, cheese 35 g, croutons 50 g and olive oil 25 g, with water 300 ml; total energy 2.6 MJ) in both solid-liquid (SM) and homogenized (HM) form, in random order, at 1-week intervals. Variables assayed were plasma glucose, insulin and glucose-dependent insulinotropic peptide (GIP) levels for 2 h and diet-induced thermogenesis (DIT) for 5 h. Plasma glucose pattern was similar after both meals. However, HM induced significantly greater insulin, GIP and DIT responses than SM. Mean integrated areas under the curves (AUC) were 1.7 (SEM 0.38) v. 1.2 (SEM 0.33) U/l per 120 min (P = 0.005) for insulin, 19.9 (SEM 2.44) v. 16 (SEM 1.92) nmol/l per 120 min (P = 0.042) for GIP, and 237.7 (SEM 16.32) v. 126.4 (SEM 23.48) kJ/300 min (P = 0.0029) for DIT respectively. Differences between GIP-AUC after HM and SM correlated significantly with differences between insulin-AUC after HM and SM (r2 0.62, P = 0.021). These findings demonstrate that homogenization of a meal results in a coordinated series of changes of physiological gastroentero-pancreatic functions and confirm that the physical state of the meal plays an important role in modulating endocrine and metabolic responses to food.

Adult↗
PubMed2000

Lymphocyte lycopene concentration and DNA protection from oxidative damage is increased in women after a short period of tomato consumption.

Several epidemiologic studies have suggested a role of tomato products in protecting against cancer and chronic diseases. In nine adult women, we evaluated whether the consumption of 25 g tomato puree (containing 7 mg lycopene and 0.3 mg beta-carotene) for 14 consecutive days increased plasma and lymphocyte carotenoid concentration and whether this was related to an improvement in lymphocyte resistance to an oxidative stress (500 micromol/L hydrogen peroxide for 5 min). Before and after the period of tomato intake, carotenoid concentrations were analyzed by HPLC and lymphocyte resistance to oxidative stress by the Comet assay, which detects DNA strand breaks. Intake of tomato puree increased plasma (P <0.001) and lymphocyte (P<0.005) lycopene concentration and reduced lymphocyte DNA damage by approximately 50% (P<0.0001). Beta-carotene concentration increased in plasma (P<0.05) but not in lymphocytes after tomato puree consumption. An inverse relationship was found between plasma lycopene concentration (r = -0.82, P<0.0001) and lymphocyte lycopene concentration (r = -0.62, P<0.01) and the oxidative DNA damage. In conclusion, small amounts of tomato puree added to the diet over a short period can increase carotenoid concentrations and the resistance of lymphocytes to oxidative stress.

Administration, Oral↗
PubMed1999

Liquid chromatography/electrospray ionization mass spectrometric characterization of flavonol glycosides in tomato extracts and human plasma.

Flavonoids continue to attract wide attention as possible very useful agents for combating free radical pathologies, i.e. the pathological states associated with free radical overproduction. Commonly used methods for the analysis of plant flavonoids include high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). On the other hand, the soft-ionization approach based on electrospray ionization (ESI-MS) permits highly selective analysis of complex matrices. In this work, we examined firstly the ESI-MS behaviour of representative aglycones and glycosides of flavonols, flavones and isoflavones with the aim of suggesting a possible relationship between structure and mass spectra. Using HPLC coupled to a diode array detector (DAD) for on-line UV spectra acquisition, and in parallel to ESI-MS for mass spectra (LC/DAD-ESI-MS), we have developed methodology to observe flavonols directly in tomato puree extract. In this way, it has been possible to detect intact flavonol glycosides in tomato extracts and to characterize a flavonol trisaccharide. For the first time, using LC/ESI-MS, it has been possible to detect intact flavonol glycosides in plasma of healthy volunteers and to provide further evidence on the absorption of flavonoid glycosides after consumption of common vegetables like tomatoes.

Calibration↗
PubMed1999

Does tomato consumption effectively increase the resistance of lymphocyte DNA to oxidative damage?

BACKGROUND: Lycopene, the main carotenoid in tomato, has been shown to be a potent antioxidant in vitro. However, there is no significant evidence of its antioxidant action in vivo. OBJECTIVE: We evaluated the effect of tomato intake on plasma carotenoid concentrations and lymphocyte resistance to oxidative stress. DESIGN: Ten healthy women (divided into 2 groups of 5 subjects each) ate a diet containing tomato puree (providing 16.5 mg lycopene) and a tomato-free diet for 21 d each in a crossover design. Before and after each diet period, plasma carotenoid concentrations and primary lymphocyte resistance to oxidative stress (evaluated by means of single-cell gel electrophoresis) were analyzed. RESULTS: After the first 21-d experimental period, total plasma lycopene concentrations increased by 0.5 micromol/L (95% CI: 0.14, 0.87) in the group that consumed the tomato diet and decreased by 0.2 micromol/L (95% CI: -0.11, -0.30) in the group that consumed the tomato-free diet (P < 0.001). Tomato consumption also had an effect on cellular antioxidant capacity: lymphocyte DNA damage after ex vivo treatment with hydrogen peroxide decreased by 33% (95% CI: 0.8%, 61%; P < 0.05) and by 42% (95% CI: 5.1%, 78%; P < 0.05) in the 2 groups of subjects after consumption of the tomato diet. CONCLUSION: The consumption of tomato products may reduce the susceptibility of lymphocyte DNA to oxidative damage.

Adult↗
PubMed1998

Physical state of meal affects gastric emptying, cholecystokinin release and satiety.

To verify the influence of food consistency on satiety mechanisms we evaluated the effects of the same meal in solid-liquid (SM) and homogenized (HM) form on satiety sensation, gastric emptying rate and plasma cholecystokinin (CCK) concentration. Eight healthy men, aged 21-28 (mean 24.5) years were given two meals (cooked vegetables 250 g, cheese 35 g, croutons 50 g and olive oil 25 g, total energy 2573 kJ, with water 300 ml) differing only in physical state: SM and HM. The subjects consumed the meals in randomized order on non-consecutive days. The sensations of fullness, satiety and desire to eat were evaluated by means of a questionnaire, gastric emptying was assessed by ultrasonographic measurement of antral area, and plasma CCK concentration was measured by radioimmunoassay. The vegetable-rich meal was significantly more satiating (P < 0.05) when in the HM form than when eaten in a SM state. Furthermore, the overall gastric emptying time was significantly slowed (255 (SEM 11) min after HM v. 214 (SEM 12) min after SM; P < 0.05) and CCK peak occurred later (94 (SEM 12) min after HM v. 62 (SEM 11) min after SM; NS) when the food was consumed in the HM form. Independently of the type of meal, antral area was significantly related to fullness sensations (r2 0.46, P = 0.004). These results demonstrate that meal consistency is an important physical food characteristic which influences both gastric emptying rate and satiety sensation. Moreover, the relationship observed between antral area and fullness sensation confirms that antral distension plays a part in the regulation of eating behaviour.

Adult↗
PubMed1998

The influence of thermic effect of food on satiety.

OBJECTIVES: To evaluate energy expenditure after three isoenergetic meals of different nutrient composition and to establish the relationship between the thermic effect of food (TEF), subsequent energy intake from a test meal and satiety sensations related to consumption. DESIGN: The study employed a repeated measures design. Ten subjects received, in a randomized order, three meals of 2331+/-36 kJ (557+/-9 kcal). About 68% of energy from protein in the high protein meal (HP), 69% from carbohydrate in the high carbohydrate meal (HC) and 70% from fat in the high fat meal (HF). SETTING: The experiments were performed at the University of Milan. SUBJECTS: Ten normal body-weight healthy women. METHODS: Energy expenditure was measured by indirect calorimetric measurements, using an open-circuit ventilated-hood system; intake was assessed 7h later by weighing the food consumed from a test meal and satiety sensations were rated by means of a satiety rating questionnaire. RESULTS: TEF was 261+/-59, 92+/-67 and 97+/-71 kJ over 7 h after the HP, HC and HF meals, respectively. The HP meal was the most thermogenic (P < 0.001) and it determined the highest sensation of fullness (P=0.002). There were no differences in the sensations and thermic effect between fat and carbohydrate meals. A significant relationship linked TEF to fullness sensation (r=0.41, P=0.025). Energy intake from the test meal was comparable after HP, HC and HF meals. CONCLUSIONS: Our results suggest that TEF contributes to the satiating power of foods.

Adult↗
PubMed1998

Absorption of lycopene from single or daily portions of raw and processed tomato.

To study the relationship between lycopene intake and plasma concentration, ten healthy female subjects were given one or more portions of tomato purée or fresh raw tomato containing 16.5 mg total lycopene (all-trans + cis forms). In Expt 1 subjects (n 9) were randomly assigned the single portions of the two tomato products and blood samples were collected to follow the change in plasma carotenoid concentrations within the first 12 h and on each of the following 5 d (104 h). In Expt 2 subjects (n 10) were divided into two groups of five each receiving daily dietary portions of tomato purée or fresh raw tomato containing 16.5 mg total lycopene for 7 d. Fasting blood samples were collected daily. In Expt 1 the plasma total lycopene (all-trans + cis forms) concentration, after the single portions of tomato purée and raw tomato, varied significantly over time, with a first peak reached after 6 h, a further increase after 12 h and a slow decrease until 104 h. In Expt 2, when the tomato products were given daily, there was a day-by-day increase in the plasma total lycopene concentration, and through the following week of a diet without tomato there was a gradual decrease. However, values did not return to basal concentrations. Plasma total lycopene concentration was higher after the tomato purée intake than after the raw tomato in both the first (F(1,8) 7.597; P < 0.025) and the second experiments (F(1,8) 12.193; P < 0.01) demonstrating a significant effect of food matrix on absorption.

Adult↗
PubMed1997

Weight, protein, fat, and timing of preloads affect food intake.

Two foods, one rich in protein (HP) and one rich in fat (HF), were employed to evaluate the effect of macronutrients on food intake and to underline the differences that occurred when the foods were served as uniform meal, as first course of a varied meal, and as a snack 2 h before a varied meal. Our results showed that HP food always exerted a higher effect on both intrameal satiation and postingestive satiety than HF food. When a uniform meal was consumed, satiation for the specific food was reached before fullness; in this condition, sensory characteristics of foods played an important role in controlling food intake and made the uniform meal more satiating than the varied one. The consumption of a snack far from a meal did not contribute to satiety; consequently, gastric filling seems to be an important factor determining the amount consumed in a varied meal.

Adult↗
PubMed1997

Determination of carotenoids in vegetable foods and plasma.

In this paper a HPLC method for the determination of lutein, zeaxanthin, beta-cryptoxanthin, alpha-carotene, beta-carotene and lycopene in mixed vegetables and fruit and in human plasma is described. The carotenoids were well separated and the separation was achieved within fifteen minutes using a HPLC system consisting of a 5 microns Vydac 201TP54C18 column, an UV detector, methanol-tetrahydrofuran (95:5 v/v) as mobile phase and a flow rate of 1.0 ml/min. The validity of the separation method was determined by evaluating the linearity of the calibration graphs of each carotenoid (between 0.1 and 1.0 microgram/ml for all compounds except lycopene between 0.1 and 0.8 microgram/ml, r = 0.999) and the accuracy of the chromatographic response (CV < 10%). The reproducibility of the retention times was also good. In the foods samples the extraction procedure was very effective whereas, the saponification step significantly damaged some of the carotenoids. In the plasma the extraction and separation of these compounds were also effective and the qualitative data obtained comparable with those reported in literature. The use of echinenone as internal standard helped to improve quality control.

Carotenoids↗
PubMed1995

Evaluation of satiety sensations and food intake after different preloads.

The reproducibility of three questions, related to fullness, satiety and desire to eat, rated on an unmarked triangle was verified. In four sessions 12 volunteers ate pasta with tomato sauce (520 kcal) and were asked to rate the sensations felt. There was no difference in rating scores of the replications so the proposed questionnaire provides a stable measure of sensations related to satiety. Subsequently three satiety conditions were studied. Two foods, one rich in carbohydrate, pasta (baked macaroni) and the other in protein, polpette (meatballs), were used as loads at two calorie levels and as preload before an "ad libitum" meal. All the three questions proved useful in discriminating between the different satiety conditions. The food intake underlines the specificity of satiety: subjects, after eating a preload which previously had satiated them, ate other foods in different amounts depending on the kind of preload eaten. Food intake was significantly higher after the pasta preload, furthermore "fullness" and "satiety" ratings were significantly highest after the meatball preload, suggesting that in our experimental conditions, meatballs were more satiating than pasta. In conclusion, this study highlights the validity of using several quite different questions to study hunger and satiety, together with the actual food intake.

Adult↗
PubMed1995

A self-administered semiquantitative food-frequency questionnaire with optical reading and its concurrent validation.

An improved semiquantitative self-administered food frequency questionnaire has been designed in order to investigate possible associations between diet and health, to plan nutrition education programmes, and to examine dietary compliance. The questionnaire consists of 16 printed forms and 16 pages with coloured photos of the most common foods and courses from the Italian diet. Instructions and other questions are included. The questionnaire uses optical reading from a scanner connected to a personal computer. The questionnaire was validated by comparing it with the seven-day weighed record method using 46 healthy adult volunteers. Significant correlations were found for all nutrients tested (Spearman rank correlation procedure), r ranging from 0.33 for ascorbic acid to 0.84 for alcohol. The two methods gave comparable results (Wilcoxon matched-pairs signed rank test) for all nutrients except riboflavin and alcohol. Similarity of the two methods in classifying relative intakes was examined by determining the frequency of similar classification into tertiles. Half of the subjects were correctly classified for most nutrients and for frequency of consumption of 18 food groups.

Adult↗
PubMed1995

Effects of physical and chemical characteristics of food on specific and general satiety.

Two high-energy-dense and two low-energy-dense Italian dishes were employed to study the effects of chemical and physical characteristics of foods on satiety. The specific satiety was firstly investigated. Then the satiating efficiency was evaluated when each dish was divided into two calorie levels (preloads) before an ad lib meal. Our results suggest that specific satiety differs, depending on the food itself rather than on energy intake. More calories were ingested with the high-energy-dense foods. The Satiating Efficiency Index (SEI) was calculated: fruit salad was the most satiating (SEI = 3.7), followed by mixed boiled vegetables (SEI = 2.4), meat balls (SEI = 1.0), and baked macaroni (SEI = 0.4). Among the variables considered, energy density, volume, protein, and firmness were the most effective in inducing satiety. In conclusion, the consumption of an adequate amount of low-energy-dense foods, high in firmness, as a first course of a meal, can help to decrease short-term intake.

Adult↗
PubMed1995

Biochemical validation of a self-administered semi-quantitative food-frequency questionnaire.

The present study is a biochemical validation of a food-frequency questionnaire (FFQ) with optical reading, i.e. containing food portion photographs to help to assess quantities. Forty-four healthy subjects, non-smokers and not taking vitamin supplements, were recruited for the study. After completion of the questionnaire, subjects were asked to keep a 7 d weighed dietary record (7DR). Three 24 h urine samples were collected on 3 different days over the week of food recording for the analysis of urea-N, P and K. On the 4th day of food recording, blood was collected for determination of alpha-tocopherol, beta-carotene and ascorbic acid. N, P and K determined in urines and from 7DR were significantly correlated (Spearman rank correlation test), r values being 0.77, 0.57 and 0.42 respectively. The correlations with the FFQ were significant only for N (r 0.45) and P (r 0.39). Blood ascorbic acid and beta-carotene concentrations correlated with dietary intake when determined from 7DR (both r 0.44), but not when determined from FFQ. No correlation was found for alpha-tocopherol. The data obtained seem to prove the validity of the FFQ in defining eating patterns in terms of some nutrients, but not vitamins, at least as far as non-supplemented subjects are concerned. The way in which foods were grouped in the questionnaire could account for these results.

Adult↗
PubMed1994

Gastric emptying of solids is markedly delayed when meals are fried.

We studied the effect of heat-treated fats on gastric emptying. Eight healthy asymptomatic volunteers (five males; age 28-41 years) ate on different days and in random order two meals identical in contents (pasta, tomato, beef, olive oil, carrots, orange, water; 870 kcal males, 700 kcal females; 47% of calories from carbohydrate, 36% from fat, 17% from protein), but cooked differently (fats fried or not). Ultrasound measurement of antral diameters was used to calculate basal antral section, its maximal dilation after the meal, the time necessary for total emptying, and the percent retention at hourly intervals. No difference was found in basal and maximal antral diameters after the two meals. On the contrary, total gastric emptying was significantly delayed after the fried meal [317.1 (24.12) vs 226.7 (18.4) min, mean (1 SEM); P < 0.002]. A significantly greater percentage of maximal antral distension was still present between 120 and 240 min after the fried meal. The glycemic response and hunger feeling were the same after the two meals, whereas there was a longer persistence of satiety and epigastric fullness after the fried meal. In conclusion, gastric emptying can be influenced not only by the meal content, but also by the way it is cooked.

Adult↗