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Biomedical subjects

A Giacosa

Publications and source records attributed to A Giacosa.

At least 37 records · Page 2Linked to original sources
PubMed2000

Phenolic compounds and squalene in olive oils: the concentration and antioxidant potential of total phenols, simple phenols, secoiridoids, lignansand squalene.

The aim of this study was to evaluate the phenolic antioxidant and squalene content in a range of olive and seed oils. A mean of 290 +/- 38 (SEM) mg squalene/100 g was detected. However, while there was a weak significant difference between extra virgin (424 +/- 21 mg/kg) and refined virgin (340 +/- 31 mg/100 g; P<0.05) olive oils, highly significant differences were evident between extra virgin olive oils (P<0.0001) refined virgin olive oils (P<0.0001) and seed oils (24 +/- 5 mg/100 g). While seed oils were devoid, on average, the olive oils contained 196 +/- 19 mg/kg total phenolics as judged by HPLC analysis, but the value for extra virgin (232 +/- 15 mg/kg) was significantly higher than that of refined virgin olive oil (62 +/- 12 mg/kg; P<0.0001). Appreciable quantities of simple phenols (hydroxytyrosol and tyrosol) were detected in olive oils, with significant differences between extravirgin (41.87 +/- 6.17) and refined virgin olive oils (4.72 +/- 215; P<0.01). The major linked phenols were secoiridoids and lignans. Although extra virgin contained higher concentrations of secoiridoids (27.72 +/- 6.84) than refined olive oils (9.30 +/- 3.81) this difference was not significant. On the other hand, the concentration of lignans was significantly higher (P<0.001) in extra virgin (41.53 +/- 3.93) compared to refined virgin olive oils (7.29 +/- 2.56). All classes of phenolics were shown to be potent antioxidants. In future epidemiologic studies, both the nature and source of olive oil consumed should be differentiated in ascertaining cancer risk.

Antioxidants↗
PubMed2000

The antioxidant/anticancer potential of phenolic compounds isolated from olive oil.

In our ongoing studies on the chemoprevention of cancer we have a particular interest in the health benefits of the Mediterranean diet, of which olive oil is a major component. Recent studies have shown that extravirgin olive oil contains an abundance of phenolic antioxidants including simple phenols (hydroxytyrosol, tyrosol), aldehydic secoiridoids, flavonoids and lignans (acetoxypinoresinol, pinoresinol). All of these phenolic substances are potent inhibitors of reactive oxygen species attack on, e.g. salicylic acid, 2-deoxyguanosine. Currently there is growing evidence that reactive oxygen species are involved in the aetiology of fat-related neoplasms such as cancer of the breast and colorectum. A plausible mechanism is a high intake of omega-6 polyunsaturated fatty acids which are especially prone to lipid peroxidation initiated and propagated by reactive oxygen species, leading to the formation (via alpha,beta-unsaturated aldehydes such as trans-4-hydroxy-2-nonenal) of highly pro-mutagenic exocyclic DNA adducts. Previous studies have shown that the colonic mucosa of cancer patients and those suffering from predisposing inflammatory conditions such as ulcerative colitis and Crohn's disease generates appreciably higher quantities of reactive oxygen species compared with normal tissue. We have extended these studies by developing accurate high performance liquid chromatography (HPLC) methods for the quantitation of reactive oxygen species generated by the faecal matrix. The data shows that the faecal matrix supports the generation of reactive oxygen species in abundance. As yet, there is a dearth of evidence linking this capacity to actual components of the diet which may influence the colorectal milieu. However, using the newly developed methodology we can demonstrate that the antioxidant phenolic compounds present in olive oil are potent inhibitors of free radical generation by the faecal matrix. This indicates that the study of the inter-relation between reactive oxygen species and dietary antioxidants is an area of great promise for elucidating mechanisms of colorectal carcinogenesis and possible future chemopreventive strategies.

Antioxidants↗
PubMed2000

Olive-oil consumption and health: the possible role of antioxidants.

In the Mediterranean basin, olive oil, along with fruits, vegetables, and fish, is an important constituent of the diet, and is considered a major factor in preserving a healthy and relatively disease-free population. Epidemiological data show that the Mediterranean diet has significant protective effects against cancer and coronary heart disease. We present evidence that it is the unique profile of the phenolic fraction, along with high intakes of squalene and the monounsaturated fatty acid, oleic acid, which confer its health-promoting properties. The major phenolic compounds identified and quantified in olive oil belong to three different classes: simple phenols (hydroxytyrosol, tyrosol); secoiridoids (oleuropein, the aglycone of ligstroside, and their respective decarboxylated dialdehyde derivatives); and the lignans [(+)-1-acetoxypinoresinol and pinoresinol]. All three classes have potent antioxidant properties. High consumption of extra-virgin olive oils, which are particularly rich in these phenolic antioxidants (as well as squalene and oleic acid), should afford considerable protection against cancer (colon, breast, skin), coronary heart disease, and ageing by inhibiting oxidative stress.

Antioxidants↗
PubMed2000

Identification of lignans as major components in the phenolic fraction of olive oil.

BACKGROUND: Because olive oil is an important component of the Mediterranean diet, it is necessary to establish unequivocal identification of the major potential antioxidant phenolic compounds it contains. METHODS: The major phenolic antioxidants in extra virgin olive oil were isolated and purified. Structural analysis was conducted using several spectroscopic techniques, including mass spectrometry and nuclear magnetic resonance (NMR). In particular, detailed (1)H and (13)C NMR data are presented, and several assignment errors in the literature are corrected. RESULTS: The data show for the first time that the lignans (+)-1-acetoxypinoresinol and (+)-pinoresinol are major components of the phenolic fraction of olive oils. These lignans, which are potent antioxidants, are absent in seed oils and virtually absent in refined virgin oils but are present at concentrations of up to 100 mg/kg (mean +/- SE, 41.53+/-3.93 mg/kg; range, 0.65-99.97 mg/kg) in extra virgin oils. As with the simple phenols and secoiridoids, there is considerable interoil variation in lignan concentrations. Foods containing high amounts of lignan precursors have been found to be protective against breast, colon, and prostate cancer. CONCLUSION: Lignans, as natural components of the diet, may be important modulators of cancer chemopreventive activity.

Chromatography, High Pressure Liquid↗
PubMed1999

Plasma levels of antioxidant vitamins and cholesterol in a large population sample in central-northern Italy.

BACKGROUND: In a population-based multicenter case-control study of diet, life-style, and gastric cancer a large series of adults, aged 30-75 years (mean 58.9 years), were randomly sampled from the general population in 3 areas of Central-Northern Italy. AIM OF THE STUDY: To evaluate the relationship between plasma levels of antioxidant vitamins and cholesterol, and sociodemographic characteristics, life-style factors, and dietary intake of selected nutrients in a sample of the Italian population. METHODS: A fasting blood sample was available for 945 subjects (553 men, 392 women). The plasma concentrations of ascorbic acid, carotene, retinol, alpha-tocopherol, and cholesterol were determined by a centralized laboratory. All participants answered to a detailed questionnaire collecting information on sociodemographic and anthropometric characteristics, smoking, alcohol drinking, and dietary habits. Covariance analysis models, with post hoc Dunnett tests, including terms for age, sex, study center, and period of blood drawing, were used for selected multiple-way comparisons of mean values of plasma nutrients. RESULTS: Mean plasma values of retinol were higher among men while women had higher levels of plasma carotene, ascorbic acid, alpha-tocopherol, and cholesterol. Plasma carotene levels showed an inverse association with body mass index, alcohol consumption, and smoking and a positive association with social class. Carotene concentrations were higher in plasma samples obtained in spring/summer, while ascorbic acid levels were higher in autumn/winter. Partial correlation co-efficients between plasma vitamin levels showed a strong correlation between carotene and ascorbic acid (0.69 in men; 0.74 in women), between carotene and alpha-tocopherol (0.44; 0.37), and between alpha-tocopherol and ascorbic acid (0.45; 0.41). Plasma alpha-tocopherol and retinol correlated with plasma cholesterol. On the other hand, plasma carotene and ascorbic acid were correlated with their estimated dietary intakes, while the intakes of other nutrients, as expected, correlated rather poorly with the respective plasma concentrations. CONCLUSIONS: Socio-economic factors, life-style, and specific nutrient intake, in addition to gender, are related to nutrient plasma levels in Italian adults and may provide specific suggestions for the prevention of chronic diseases.

Adult↗
PubMed1999

Risk indicators of organic diseases in uninvestigated dyspepsia: a one-week survey in 246 Italian endoscopy units.

OBJECTIVE: To evaluate the predictive value of demographic and clinical features and of the results of an office-based test for Helicobacter pylori antibodies, in the presence of organic dyspepsia. DESIGN: Over a 1-week period, 2206 consecutive patients first referred for endoscopy in 246 Italian centres were included. METHODS: Demographic and clinical features, endoscopy findings, and histological diagnosis of H. pylori infection were recorded for all patients. IgG antibodies to H. pylori were determined in 2128 cases by a rapid, immunochromatographic method (Flex Sure HP, S.K.D., San Jose, CA). RESULTS: Endoscopic abnormalities were found in 939 patients (42.6%). Histologically assessed H. pylori infection was predictive for duodenal ulcer (odds ratio (OR), 6.79; 95% confidence interval (CI), 4.4-10.5). Being male (OR, 1.97; 95% CI, 1.7-2.3), older than 40 years (OR, 1.81; 95% CI, 1.5-2.2), a smoker (OR, 1.88; 95% CI, 1.6-2.3), and presenting nocturnal awakening (OR, 1.62; 95% CI, 1.3-2.0) were independently associated with secondary dyspepsia. Epigastric (OR, 1.50; 95% CI, 1.2-1.9) and retrosternal pain (OR, 1.39; 95% CI, 1.1 -1.8) severe enough to affect the usual activities were predictive of organic diseases. The results of the Flex Sure HP test correlated poorly with histological findings. CONCLUSIONS: Male gender, older age, cigarette smoking, a family history of peptic ulcer, symptoms severe enough to induce awakening, epigastric/retrosternal pain severe enough to influence the usual activities are all independently (although weakly) associated with organic dyspepsia. H. pylori infection is strongly associated with duodenal ulcer, but the rapid test we used was not sensitive enough to achieve clinical utility.

Adult↗
PubMed1999

Energy intake, overweight, physical exercise and colorectal cancer risk.

Epidemiological studies on risk factors for CRC have focused mainly on diet. In any case, the results of these studies show several inconsistencies, except for the beneficial role of high intake of vegetables and, to some lesser extent, of fruit. Weight and height have also been studied, partly because they reflect the balance between energy intake and expenditure in different age periods. Energy intake, body size and physical activity will be reviewed in this paper focusing mostly on recent data coming from Italian, English and Scandinavian studies. Overweight has long been recognized as a risk factor for hormone related and other cancers and this is confirmed not simply from case-control studies but from large cohort studies as well. The major findings of recent Italian studies are that excessive weight at various ages predicts colorectal cancer risk in men while in women, abdominal obesity, as indicated by a high WHR, represents a more reliable risk indicator. If all men could reduce their BMI below 25, about 9% of male colorectal cancer might be avoided in Italy. A decrease of WHR below 0.82 might reduce colorectal cancer in women by 19%. In addition, the epidemiological evidence consistently shows that physical activity reduces the risk of colon cancer. On the contrary, evidence on rectal cancer is less impressive. Some uncertainty still exists in relation to the intensity and duration of physical activity. In conclusion, body size control along all life and physical activity represent important factors to prevent colon cancer and a wide range of chronic conditions. Therefore, strategies to favour these goals through counselling from health-care providers, regulatory changes and programs aimed at individuals and communities should be implemented.

Adult↗
PubMed1998

Body size and colorectal-cancer risk.

Individuals whose energy intake exceeds expenditure are at increased risk of colorectal cancer. To determine whether body-size measurements at different ages were risk factors for cancer of the colon-rectum, we carried out a hospital-based case-control study in 6 Italian areas, 2 of which were in the South. Interviews were conducted with 1,217 subjects of both genders with incident histologically confirmed cancer of the colon, 726 with cancer of the rectum, and 4,136 controls hospitalized for acute, non-neoplastic, non-digestive conditions. The questionnaire included information on sociodemographic factors, and physical activity, a validated dietary history, height, weight at diagnosis and at 12, 30 and 50 years of age and waist-to-hip ratio (WHR). After allowance for education, physical activity, energy intake, family history of colorectal cancer and recent change in weight, the body-mass index (BMI) was significantly associated with colorectal-cancer-risk in men (odds ratio, OR, in highest vs. lowest quintile = 1.7; 95% confidence interval, CI, 1.3-2.3), but not in women (corresponding OR = 0.9; 95% CI, 0.7-1.2). Cases of both gender tended to have higher BMI than controls in adolescence, young adulthood and middle age. Height appeared unrelated to risk. In women, but not in men, WHR was positively associated with risk, independently of BMI (OR for > or = 0.90 vs. < or = 0.81 = 1.6; 95% CI; 1.2-2.1). Thus, excessive weight predicts colorectal-cancer risk in men, whereas abdominal obesity (i.e., a high WHR) represents a more reliable risk indicator in women.

Adult↗
PubMed1998

Olive oil, other seasoning fats, and the risk of colorectal carcinoma.

BACKGROUND: An association between fats and colorectal carcinoma has been suggested, but the epidemiologic evidence by type of dietary fat is far less clear. Colorectal carcinoma rates have been relatively low in Mediterranean countries compared with most other Western countries, but the components of the Mediterranean diet responsible for this favorable pattern are unclear. METHODS: The relationship between various added (seasoning) fats and colorectal carcinoma risk was investigated using data from a case-control study conducted between January 1992 and June 1996 in six Italian areas. Cases were 1953 patients with incident, histologically confirmed colorectal carcinoma (1225 of the colon and 728 of the rectum) admitted to the major teaching and general hospitals in the study areas. Controls were 4154 subjects with no history of cancer who were admitted to hospitals in the same catchment areas for acute, nonneoplastic diseases unrelated to the the digestive tract and requiring no long term modifications of diet. Dietary habits were investigated using a validated food frequency questionnaire including 78 items. Lipid intake was estimated by taking into account the content of seasoning lipids in different dishes, the frequency of consumption and portion size of each dish, and individual fat intake patterns. RESULTS: The odds ratios (OR) for successive tertiles of olive oil intake, compared with the lowest one, were 0.87 (95% confidence interval [CI], 0.75-1.01) and 0.83 (95% CI, 0.70-0.99) (chi2trend = 4.49, P = 0.03) when colorectal carcinoma was analyzed as a whole, 0.82 (95% CI, 0.68-0.98) and 0.81 (95% CI, 0.66-0.99) (chi2trend = 4.05, P = 0.04) for colon carcinoma, and 0.96 (95% CI, 0.77-1.19) and 0.88 (95% CI, 0.66-1.12) for rectal carcinoma. For specific seed oils (including sunflower, maize, peanut, and soya), the OR for colorectal carcinoma was 0.91 in the highest tertile of intake, and the corresponding values were 1.01 for mixed seed oils and 0.93 for butter. None of these estimates was significantly different from the unity. Allowance for vegetable intake attenuated the apparent protection from olive oil consumption (OR, 0.94 for colon and 0.97 for rectum for the highest tertile), which still was apparent in younger subjects (OR, 0.82 for colon and 0.69 for rectum). CONCLUSIONS: In this study, seasoning fats did not appear to increase the risk of colorectal carcinoma, and there was little evidence for a differential effect by fat type. If such a differential effect exists, it is minor and could favor olive oil.

Adult↗
PubMed1998

Italian study on colorectal cancer with emphasis on influence of cereals.

To elucidate the influence of diet on colorectal carcinogenesis, 1225 subjects with cancer of the colon, 728 with cancer of the rectum and 4154 controls, hospitalized with acute non-neoplastic diseases, were interviewed between 1992 and 1996 in six Italian areas. The validated food frequency questionnaire included 79 questions on food items and recipes which were grouped into 16 food groups. After allowing for nondietary confounding factors and total energy intake, a significant trend towards an increasing risk of colorectal cancer with increasing intake was found for bread and cereal dishes (odds ratio for increase of one daily serving 1.11), cakes and desserts (odds ratio 1.02) and refined sugar (odds ratio 1.11). The intake of fish (odds ratio 0.53), raw and cooked vegetables (odds ratios 0.79 and 0.65, respectively) and fruit (odds ratio 0.93) showed an inverse association with risk. Wholemeal bread was consumed by only 12.5% of cases and 13.9% of controls and, at variance with refined bread, did not show a significant direct association with colorectal cancer risk (odds ratio 0.88). In view of these findings, current hypotheses on the carcinogenic effects of refined starchy foods and refined sugar should be revised to take into account the digestive physiology of carbohydrates and the possible relationship between insulin and colon cancer. The beneficial influence of most vegetables is confirmed, and a possible difference between refined and wholemeal bread is suggested.

Adult↗
PubMed1998

Primary prevention of colorectal cancer through fibre supplementation.

Epidemiological studies have emphasized the importance of diet in the etiology of large bowel cancer. A high intake of dietary fibre has been hypothesized to decrease the risk of colorectal cancer. This hypothesis is now being tested within the framework of intervention studies. Supplemental fibre is being used in four chemopreventive trials as wheat bran (22.5 g/day together with vitamins C and E, New York study; 25 g/day, Australian study; 50 g/day, Toronto study; 13.5 g/day, Arizona study) and in one trial as ispaghula husk (a mucilaginous substance) at 3.8 g/day (European Cancer Prevention Organization study). One study is evaluating the effect of fibre on adenoma size in patients with familial polyposis and an intact rectum, and the other four studies are focusing on the recurrence of adenoma in patients with previous adenomas. The results available so far provide some evidence for the inhibition of adenoma growth through a high-fibre and/or low-fat diet. Further results are expected within a year. If there is sufficient evidence for a protective effect of dietary fibre on colorectal carcinogenesis, a simple, safe and inexpensive prophylaxis for a very common cancer will be indicated.

Chemoprevention↗
PubMed1997

Intake of selected micronutrients and risk of colorectal cancer.

The relationship between various micronutrients and colorectal cancer risk was investigated using data from a case-control study conducted between January 1992 and June 1996 in Italy. Cases were 1,953 incident, histologically confirmed colorectal cancers (1,225 of the colon and 728 of the rectum), admitted to the major teaching and general hospitals in the study areas, and 4,154 controls with no history of cancer, admitted to hospitals in the same catchment areas for acute, non-neoplastic diseases unrelated to the digestive tract and requiring no long-term modifications of the diet. Dietary habits were investigated using a validated food-frequency questionnaire. Odds ratio (ORs) were computed after allowance for age, sex and other potential confounding factors, including physical activity, total energy and fibre intake. For most micronutrients, ORs were below unity with increasing quintile of intake. The most consistent protective effects were for carotene, riboflavin and vitamin C (Multivariate ORs from the continuous model, with unit set as the difference between the upper cut-point of the 4th quintile and that of the 1st one, were 0.65, 0.73 and 0.80, respectively). Inverse relationships were observed also for calcium and vitamin D (ORs of 0.85 and 0.93, respectively). When the combined effect of calcium and vitamin D and selected anti-oxidants was considered, the OR reached 0.46 in subjects reporting high calcium/vitamin D and high anti-oxidant intake compared to those reporting low intake of both groups of micronutrients. Most results were apparently stronger for colon cancer and among females. Our results provide further support for a protective effect of several micronutrients on colorectal cancer risk and some indications for a specific and stronger effect of selected anti-oxidants.

Adult↗
PubMed1997

Food groups and risk of colorectal cancer in Italy.

The proportion of colorectal cancer attributed to dietary habits is high, but several inconsistencies remain, especially with respect to the influence of some food groups. To further elucidate the role of dietary habits, 1,225 subjects with cancer of the colon, 728 with cancer of the rectum and 4,154 controls, hospitalized with acute non-neoplastic diseases, were interviewed between 1992 and 1996 in 6 different Italian areas. The validated food-frequency questionnaire included 79 questions on food items and recipes, categorised into 16 food groups. After allowance for non-dietary confounding factors and total energy intake, significant trends of increasing risk of colorectal cancer with increasing intake emerged for bread and cereal dishes (odds ratio [OR] in highest vs. lowest quintile = 1.7), potatoes (OR = 1.2), cakes and desserts (OR = 1.1), and refined sugar (OR = 1.4). Intakes of fish (OR = 0.7), raw and cooked vegetables (OR = 0.6 for both) and fruit other than citrus fruit (OR = 0.7) showed a negative association with risk. Consumption of eggs and meat (white, red or processed meats) seemed uninfluential. Most findings were similar for colon and rectum, but some negative associations (i.e., coffee and tea, and fish) appeared stronger for colon cancer. Our findings lead us to reconsider the role of starchy foods and refined sugar in light of recent knowledge on the digestive physiology of carbohydrates and the insulin/colon cancer hypothesis. The beneficial role of most vegetables is confirmed, with more than 20% reduction in risk of colorectal cancer from the addition of one daily serving.

Adult↗
PubMed1997

Aspirin and colorectal cancer.

The relationship between aspirin use and colorectal cancer risk was examined by a case-control study in Italy. Regular aspirin use was reported by only 47 (3.5%) cases and 77 (4.1%) control subjects, giving a multivariate odds ratio (OR) of 0.7 (95% CI 0.5-1.0) after allowance for education, physical exercise and selected dietary factors.

Adult↗
PubMed1997

The antioxidant potential of the Mediterranean diet.

The Mediterranean diet not only produces favourable effects on blood lipids but also protects against oxidative stress. Oxidative damage is thought to represent one of the mechanisms leading to chronic diseases such as atherosclerosis and cancer. Many studies suggest that a link exists between fruit and vegetables in the diet or the amounts of plasma antioxidant vitamins (ascorbic acid, tocopherol and carotenoids) and risk of death from cancer or coronary heart diseases. Although a large emphasis has been given to different components of the diet, attention has recently shifted to the diet as a whole. The Mediterranean diet is able to modulate oxidative stress through complex mechanisms and not just the high antioxidant compound content. The preference for fresh fruit and vegetables in the Mediterranean diet will result in a higher consumption of raw foods, a lower production of cooking-related oxidants and a consequent decreased waste of nutritional and endogenous antioxidants. The high intake of antioxidant and fibre helps to scavenge even the small amount of oxidants or oxidized compounds.

Antioxidants↗
PubMed1997

High-risk subjects for vitamin deficiency.

Chronic deficiency of various vitamins can influence the occurrence of some chronic degenerative diseases such as cancer, cardiovascular pathology, cataract, arthritis, disorders of the nervous system and photosensitivity. Similarly, vitamin intake can influence various disorders in infants and elderly people, in burns and in subjects following unbalanced diets or undergoing strenuous physical exercise. Among vitamins, beta-carotene, vitamin E and vitamin C have received most attention, particularly in the prevention of oxidative damage from free radicals. It is supposed that each vitamin plays a different role in the pathogenesis of various diseases, depending on the type of damage relevant to a specific disease. Results from different studies are still far from conclusive and the effects on longevity are not well defined. In industrialized countries, vitamin deficiencies seem to be related only to specific and clearly identifiable groups in the population: therefore, at the moment, it seems more advisable to target vitamin supplementation at risk groups.

Adult↗
PubMed1997

Vitamins and cancer chemoprevention.

Chemoprevention is in an area of cancer research with perhaps the greatest potential for reducing cancer mortality. Several agents, and in particular antioxidant vitamins, appear to be effective against early rather than later steps of the premalignant process at different sites. Particular attention must be paid to possible side effects and safety of the agents and to optimal doses in long-term administration regimens. The results of numerous trials on the preventive role of vitamins (e.g. beta-carotene, retinols, retinoids, alpha-tocopherol, ascorbic acid, folic acid) are contradictory and far from conclusive. Multiple primary and secondary intervention trials currently under way should assess in the coming years the role of some vitamins in the prevention of various cancers (oral cavity, pharynx, oesophagus, colon, lung, breast, skin, cervix, bladder).

Animals↗