A comprehensive review of healthy effects of vegetarian diets.

AIMS: A comprehensive review comparing the effect of vegetarian (V) and non-vegetarian (NV) diets on the major cardiometabolic diseases' outcomes was performed. DATA SYNTHESIS: We performed literature research (up to December 31, 2022) of the evidence separately for vascular disease (VD), obesity (OB), dyslipidemia (Dysl), hypertension (HPT), type 2 diabetes (T2D), metabolic syndrome (MetS), analyzing only cohort studies and randomized controlled studies (RCTs) and comparing the effect of V and NV diets. Cohort studies showed advantages of V diets compared to NV diets on incidence and/or mortality risk for ischemic heart disease, overweight and OB risk. Most cohort studies showed V had lower risk of HPT and lower blood pressure (BP) than NV and V diets had positive effects on T2D risk or plasma parameters. The few cohort studies on the risk of MetS reported mixed results. In RCTs, V diets, mainly low-fat-vegan ones, led to greater weight loss and improved glycemic control than NV diets and in the only one RCT a partial regression of coronary atherosclerosis. In most RCTs, V diets significantly reduced LDL-C levels (but also decreased HDL-C levels) and BP. CONCLUSIONS: In this comprehensive review of the association between V diets and cardiometabolic outcomes, we found that following this type of diet may help to prevent most of these diseases. However, the non-uniformity of the studies, due to ethnic, cultural, and methodological differences, does not allow for generalizing the present results and drawing definitive conclusions. Further, well-designed studies are warranted to confirm the consistency of our conclusions.

Position paper on vegetarian diets from the working group of the Italian Society of Human Nutrition.

BACKGROUND: Interest in vegetarian diets is growing in Italy and elsewhere, as government agencies and health/nutrition organizations are emphasizing that regular consumption of plant foods may provide health benefits and help prevent certain diseases. METHODS AND RESULTS: We conducted a Pubmed search, up to September, 2015, for studies on key nutrients (proteins, vitamin B12, iron, zinc, calcium, vitamin D, and n-3 fatty acids) in vegetarian diets. From 295 eligible publications the following emerged: Vegetarians should be encouraged to supplement their diets with a reliable source of vitamin B12 (vitamin-fortified foods or supplements). Since the plant protein digestibility is lower than that of animal proteins it may be appropriate for vegetarians to consume more proteins than recommended for the general population. Vegetarians should also be encouraged to habitually consume good sources of calcium, iron and zinc - particularly vegetables that are low in oxalate and phytate (e.g. Brassicaceae), nuts and seeds, and calcium-rich mineral water. Calcium, iron, and zinc bioavailability can be improved by soaking, germination, and sour-dough leavening that lower the phytate content of pulses and cereals. Vegetarians can ensure good n-3 fatty acid status by habitually consuming good sources of a-linolenic acid (walnuts, flaxseeds, chia seeds, and their oils) and limiting linoleic acid intake (corn and sunflower oils). CONCLUSIONS: Well-planned vegetarian diets that include a wide variety of plant foods, and a reliable source of vitamin B12, provide adequate nutrient intake. Government agencies and health/nutrition organizations should provide more educational resources to help Italians consume nutritionally adequate vegetarian diets.

The temporal effect of a wild blueberry (Vaccinium angustifolium)-enriched diet on vasomotor tone in the Sprague-Dawley rat.

BACKGROUND AND AIMS: We have previously reported that wild blueberry (Vaccinium angustifolium)-enriched diets (WB) attenuate aortic adrenergic response through endothelial-mediated pathways. The duration of dietary intervention necessary to induce the positive changes on vasomotor tone has not been studied to date. Thus, our objective was to investigate the temporal effect of WB consumption on vascular function and reactivity in Sprague-Dawley (SD) rat aorta after 4 and 7 weeks of dietary treatment. METHODS AND RESULTS: Forty male SD rats were randomly assigned to a control (AIN-93) (C) or a WB diet for 4 or 7 weeks. Vascular ring studies were conducted in 3-mm isolated rat aortic rings to investigate vasoconstriction induced by six doses of the α(1)-adrenergic agonist, L-phenylephrine (Phe, 10(-8)-3×10(-6) M) alone or in the presence of the NOS inhibitor, L-N(G)-monomethyl-arginine (L-NMMA, 10(-4)M). The maximum force of contraction (F(max)) and vessel sensitivity (pD(2)) were determined. Analysis of variance revealed no significant differences on F(max) after 4 weeks of the WB diet but only a significant increase in pD(2) in the absence of L-NMMA. Seven week WB consumption significantly attenuated contraction in response to L-Phe and resulted in lower pD(2). Inhibition of NOS induced a significant increase in the constrictor response in both diet groups at both time periods, with the WB group fed for 7 weeks having the greater response. CONCLUSION: Thus wild blueberries incorporated into the diet at 8% w/w positively affect vascular smooth muscle contractility and sensitivity but these effects are evident only after 7 weeks of WB consumption.

Nutritional evaluation of some processed catering foods.

Five prepared catering dishes were analysed to evaluate the proximate composition and the fatty acids, vitamin E, thiamine and riboflavin content. The correspondent values were calculated from actually available food composition tables (two from Italy, one from the UK and one from the USA). When using more than one database to calculate the composition of a complex recipe the average values were similar to the analytical ones despite the wide range reported for some variables. However, there was no significant difference in the statistical analyses between the analytical values and databases, or among the databases themselves. Therefore if the composition of a specific recipe is required, analyses would be advisable, but the available databases are quite adequate if the evaluation is for groups of people, even allowing for the seasonal variability of ingredients.

Study design of a total reference diet for a population in Northern Italy.

A market based of 91 food items was purchased in Northern Italy, based on a list taken from a food survey previously conducted in the same area. The food items from the survey were grouped into 14 categories. Food samples were collected, homogenized, and frozen for the analysis of both the nutrient content and the levels of mineral contaminants. The study design and decision processes behind the choice of type and quantity of each food are explained. The relative quantities of each food group were compared with those from two similar studies. Finally, energy, nutrients, and mineral contaminants obtained by direct analysis were compared with the calculations given on the food composition tables. The comparison between the analyzed and calculated data only showed marked differences in phosphorus, sodium, potassium, and copper intakes.

Influence of organic acids on aluminium absorption and storage in rat tissues.

Six groups of 16 rats each were fed a standard diet for 8 weeks. Aluminium (Al) complexed with organic anions (citrate, lactate, malate, or tartrate) was added to the diet of four of the groups and aluminium hydroxide to the diet of one group (control 'Al +'). Aluminium concentrations in the diets were 1500-2000 mg/kg. The sixth group (control 'Al -') served as control. Plasma, bone (femur), kidneys, cerebral cortex and cerebellum levels of aluminium were determined at 4 and 8 weeks. All the complexing agents increased tissue accumulations, compared with values in the two control groups, especially citrate in bone and kidneys and lactate in cerebral cortex. There were no significant differences (P < 0.05) in aluminium levels in the tissues considered between the 'Al +' and 'Al -' control groups. Our results show the ability of dietary organic acids to increase aluminium absorption and tissue accumulation and indicate that concurrent intake of aluminium and dietary organic acids is not appropriate.

Dietary selenium intake and selenoproteins in rat plasma.

Selenium (Se) is vital for animals and humans, as it is an essential component of Se-dependent glutathione peroxidase (GPx), an enzyme that reduces peroxides and protects cells against the damaging effects of oxidation. Se has, however, been found in rat plasma even when the enzymatic activity of GPx is very low, supporting the hypothesis that Se is also bound to other proteic structures. The purpose of this work was partially to purify the selenium-containing proteins in plasma, without denaturation, by isoelectrofocusing. We observed two pH intervals in the plasma where Se-containing proteins concentrated upon focusing: the first, at pH 6.0 +/- 0.2 and with GPx activity, and the second, between pH 4.6 and 5.4, with no enzymatic activity. We can infer therefore that other Se-containing proteins are present at a lower pH than 6, and in particular between 4.6 and 5.4

Polycyclic aromatic hydrocarbon contamination in the Italian diet.

The content of total and carcinogenic polycyclic aromatic hydrocarbons (PAHs) in Italian foods was measured. The highest levels of PAHs were found in pizza baked in wood-burning ovens and barbecued beef and pork. Relatively high levels were also found in beet greens and squash, apples and bread, fried beef, pork and rabbit, cured meats and chocolate. Conversely low levels were detected in potatoes and cooked fish, beverages and eggs. The daily intake of total and carcinogenic PAHs also was calculated by multiplying the average consumption of each food by its mean concentration of PAHs. Cereal and milk products, meat, vegetables and fruits were the highest contributors to total PAH intake, since these products are the most important dietary components in Italy. The calculated total dietary PAH intake was 3 micrograms/day per person. The calculated intake of carcinogenic PAHs was 1.4 microgram/day per person. The dietary intake of PAHs was high compared with the calculated respiratory intake (370 ng/day) owing to polluted city air in Italy. These results confirm that food is the major source of human exposure to PAHs, due in particular to the high consumption of contaminated cereal products.

Digestibility of carbohydrates from rice-, oat- and wheat-based ready-to-eat breakfast cereals in children.

OBJECTIVE: To study the effect of the presence and quality of dietary fibre in ready-to-eat (RTE) breakfast cereals on completeness of carbohydrate digestion in children and on starch susceptibility to alpha-amylase in vitro. DESIGN: A controlled intervention study. SUBJECTS: Eight 3-8-year-old healthy children. INTERVENTIONS: Completeness of digestion was evaluated by assessing the amount of carbohydrates apparently fermented into the colon using the breath-H2 technique after consumption in random order, of five breakfast tests containing boiled rice (either alone or supplemented with 3 g of lactulose) as reference food, or RTE cereals based on rice (low-fibre), wheat (high insoluble fibre) and oats (high-soluble fibre). The potential glycaemic impact of the products was estimated in vitro by assessing starch susceptibility to alpha-amylolysis using an enzymatic-dialysis method. RESULTS: Compared to boiled rice and to rice-based RTE cereal, wheat- and oat-based RTE cereals both significantly (P < 0.05) increased the amount of apparently fermented carbohydrates (+1.1 +/- 1.7% of total breakfast carbohydrate fermented for rice, +5.6 +/- 0.9% for wheat and +9.4 +/- 3.7% for oats; mean +/- SEM), calculated using the excess H2 in breath after lactulose as standard. All products showed similar in vitro digestibility, resulting in estimated glycaemic indexes of 117.5 (24.0) for rice, and 105.7 (14.1) for oats-based, 128.4 (17.6) for wheat-based, and 129.8 (16.6) [mean 95% CI)] for rice-based RTE cereals. CONCLUSIONS: Results suggest that the presence of fibre in RTE breakfast cereals, in particular soluble fibre, increases colonic fermentation in children whereas it seems not to affect glucose availability.

Intestinal absorption of manganese: an in vitro study.

Our work on isolated rat intestine aimed at studying the hypothesis that the intestinal transport of manganese was carrier-mediated and, consequently, subjected to saturation. Our results confirm this hypothesis, assessing the concentration of carrier saturation for manganese at 0.5 mM. As this concentration, which may determine self-limitation in the intestinal absorption of this metal, is much higher than the maximal allowed concentration of the EEC Standard (50 mg/l), food and water should be carefully monitored for their manganese content in order to avoid reaching toxic concentrations in blood and tissues.

Complement activation and polymorphonuclear neutrophil leukocyte elastase in sepsis. Correlation with severity of disease.

Complement activation is necessary for an adequate immune and inflammatory response to infections. Activation releases anaphylatoxins that cause vasodilation, increase vascular permeability, and trigger release of polymorphonuclear neutrophil leukocyte (PMN) lysosomal enzyme and oxygen radicals. Under normal circumstances, an orderly progression of such events has a beneficial antimicrobial effect. The same mechanism, however, when uncontrolled, may damage host tissues. To provide information about the clinical importance of such events in sepsis, different complement parameters (C3, C4, and the desarginated forms of C3a [C3a(des)-Arg] and C5a [C5a(des)-Arg]), PMN elastase, and malondialdehyde (a by-product of membrane peroxidation by oxygen radicals) were measured daily in 26 septic patients and correlated with two objectively assessed and previously validated severity scores (acute physiology and chronic health evaluation [APACHE II] and Sepsis Severity Score [SSS]). Nonsurvivors (n = 12) had significantly greater and longer lasting complement activation than that in survivors, as reflected by higher levels of catabolic peptides (C3a(des)-Arg) and lower levels of native proteins (C3 and C4). C3a(des)-Arg, C3, C4, and the C3a(des)-Arg-C3 ratio were correlated with Sepsis Severity Scores. Polymorphonuclear neutrophil leukocyte elastase levels were higher in nonsurvivors and were correlated with C3a(des)-Arg and the C3a(des)-Arg-C3 ratio. Malondialdehyde levels were significantly higher in all patients than in controls, without, however, any relationship to severity of disease or clinical outcome. Since the higher and more persistent the complement activation and polymorphonuclear neutrophil leukocyte stimulation, the worse the patient's prognosis, we conclude that these mechanisms may be important in the clinical development of sepsis.

Is colonic fermentation minimized by increasing meal frequency?

It has been suggested that, although increasing meal frequency has metabolic advantages in terms of carbohydrate and lipid metabolism, the efficiency of small intestinal absorption may be enhanced, thus reducing the extent of colonic fermentation. Since this may be undesirable, we have tested whether increasing meal frequency reduces the amount of carbohydrate fermented into the colon. Accordingly, seven healthy male volunteers took, in random order, two identical 2-week metabolic diets divided into either seventeen or three meals daily. On day 13 of each period measurements were made throughout the day of breath H2 and serum acetate, as markers of colonic fermentation. Mean levels of both breath H2 and acetate were similar on both diets, being lower on nibbling by 3.2 +/- 0.8 ppm and 25 +/- 9 mumols/l respectively (not significant). This study failed to demonstrate an effect of more efficient carbohydrate absorption with increased meal frequency.

Availability of selenium in dough and biscuit in comparison to wheat meal.

We studied the availability of selenium in processed foods and whole wheat diets for restoring the Se content and glutathione peroxidase (GSHPx) activity in the blood and liver of selenium-depleted rats. The Se content in the rat diets ranged from 225 to 342 micrograms Se/kg diet. Different selenium sources and different Se amounts had little influence on the Se levels in the blood and liver of repleted rats. Se from processed foods did not completely restore the GSHPx activity in whole blood and liver as happened with Se coming from wheat. These results indicate that it is the milling processes of the flour production, and not the cooking, which decrease the availability of Se for GSHPx synthesis in rats.

Effects of durum wheat dietary selenium on glutathione peroxidase activity and Se content in long-term-fed rats.

A 120-day assay was made of Se concentration and glutathione peroxidase Se-dependent (GSHpx) activity in plasma, erythrocytes and liver of female Sprague-Dawley rats fed either a Torula diet (low Se content) or a durum wheat diet providing 28-405 micrograms of Se/kg diet. For all groups there was a strong increase for the first 20 days in plasma and liver Se; for the remaining period the increase was lower; erythrocyte Se increased, as before, in the first 60 days for groups fed 28-200 micrograms/kg diet, after this period it decreased in the groups fed high-Se diet. Plasma GSHpx activity was extremely sensitive to dietary Se levels and increased for up to 40 days of repletion, after which the trend was to plateau; liver and erythrocyte GSHpx activity increased continuously for up to 60 days of supplementation, it then remained constant. The correlation between Se in plasma, liver and erythrocytes and its GSHpx activity was statistically significant (p less than 0.001). These results suggested that in long-term-fed rats, a diet with levels of 100-400 micrograms/kg was sufficient to satisfy the rat's needs; there was no evidence of toxicity and, moreover, in all tissues, an amount of Se, probably bound to proteins with unknown functions, was present.

Thiamin, riboflavin and pyridoxine status in chronic renal insufficiency.

The restricted diets of patients with chronic renal insufficiency (CRI) can lead to inadequate intake of some vitamins. We studied thiamin, riboflavin and pyridoxine nutritional status of CRI subjects on unrestricted or low-protein diet. Results show that riboflavin status is inadequate even before the beginning of the follow up and worsens with time for both groups, while thiamin and pyridoxine status becomes inadequate in some patients after a long period on the low-protein diet. Water-soluble vitamin supplements could improve the nutritional status of CRI patients on protein-restricted diet.

Effects of various dietary selenium intakes on the levels of blood glutathione-peroxidase and selenium in long-term fed rats.

Female Sprague-Dawley rats were fed a torula diet or wheat diets containing 4 levels of Se partially supplemented (24-402 ppb) for 120 days. Selenium content and glutathione-peroxidase (GSH-Px) activity in plasma and erythrocytes were measured every 20 days. In rats fed torula diet or basal wheat diet, plasma Se (P-Se) increased for up to 60 days, then remained constant, while erythrocytes Se (E-Se) and E-GSH-Px decreased in basal-diet rats during the first 40-60 days, then increased. In rats fed supplemented diets, P-Se and P-GSH-Px increased more rapidly than E-Se and E-GSH-Px, plateauing at 60-80 days. The best correlation was found between P-GSH-Px and dietary Se indicating that this index is the most sensitive for evaluating changes resulting from different Se intakes. In addition, correlations became more significant with time. The results from rats fed a low Se diet suggest the existence of regulatory mechanisms working in different ways and at different times in plasma and erythrocytes.

Vitamin A, E and C nutriture of elderly people in North Italy.

The vitamin A, E and C nutritional status of 313 non institutionalized elderly people living in a small town and in an agricultural village of North Italy has been evaluated. From results obtained it is possible to say that all the population tested is at low risk for vitamin A deficiency, while 10-20% of people over 70 living in the small town have low levels of vitamin E. On the contrary, the nutritional status of ascorbic acid, where the levels are inadequate in more than 50% of the population, is worrying.

Chemical composition of Italian cooked dishes.

50 different food items, including "first courses", main and side dishes, cheese and pork products, have been analysed for proteins, carbohydrates, fats, fiber, thiamin, riboflavin and vitamin A. The results obtained have been compared with the values determined on food samples by means of food composition tables so as to have information about the quantitative variations occurring after food processing. It can be concluded that composition tables report sufficiently reliable data with regard to the protein, fat and carbohydrate content for most of the considered food items. On the other hand, values for vitamins are lower by analysis than by calculation, suggesting that it is necessary to continually check data.

[High resolution liquid chromatography (HPLC) analysis of the vitamin A and beta-carotene content of heat-treated precooked food]. / Analisi mediante cromatografia liquida ad alta risoluzione (HPLC) del contenuto di vitamina A e beta-carotene di piatti precucinati termicamente trattati.

Vitamin A and beta-carotene contents in 22 samples of precooked foods were determined before and after the use of various reheating techniques. The method used includes saponification by boiling with etOH and KOH, diethyl ether extraction in the presence of BHT as antioxidant, drying under controlled conditions and detection of the vitamins by HPLC. The results suggest good applicability of the procedure to food analysis and show how reheating processes can have a significant influence on the vitamin content of such foodstuffs.