Association between high dietary intake of the n-3 polyunsaturated fatty acid docosahexaenoic acid and reduced risk of Crohn's disease.

BACKGROUND: There are plausible mechanisms for how dietary docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid, could prevent Crohn's disease (CD). AIM: To conduct a prospective study to investigate the association between increased intake of DHA and risk of CD. METHODS: Overall, 229 702 participants were recruited from nine European centres between 1991 and 1998. At recruitment, dietary intakes of DHA and fatty acids were measured using validated food frequency questionnaires. The cohort was monitored through to June 2004 to identify participants who developed incident CD. In a nested case-control analysis, each case was matched with four controls; odds ratios (ORs) were calculated for quintiles of DHA intake, adjusted for total energy intake, smoking, other dietary fatty acids, dietary vitamin D and body mass index. RESULTS: Seventy-three participants developed incident CD. All higher quintiles of DHA intake were inversely associated with development of CD; the highest quintile had the greatest effect size (OR = 0.07; 95% CI = 0.02-0.81). The OR trend across quintiles of DHA was 0.54 (95% CI = 0.30-0.99, Ptrend  = 0.04). Including BMI in the multivariate analysis, due to its correlation with dietary fat showed similar associations. There were no associations with the other dietary fatty acids studied. CONCLUSION: There were inverse associations, with a biological gradient between increasing dietary docosahexaenoic acid intakes and incident Crohn's disease. Further studies in other populations should measure docosahexaenoic acid to determine if the association is consistent and the hypothesis tested in randomised controlled trials of purely docosahexaenoic acid supplementation.

Validity of food frequency questionnaire estimated intakes of folate and other B vitamins in a region without folic acid fortification.

BACKGROUND/OBJECTIVES: B vitamins have been implicated in major chronic diseases but results have been inconsistent. This study evaluated the accuracy of dietary intakes of folate, vitamin B12, riboflavin and vitamin B6 as measured by the Northern Sweden Food Frequency Questionnaire (FFQ) against repeated 24-h recalls (24HR) and plasma levels, taking into consideration the MTHFR 677C>T polymorphism. SUBJECTS/METHODS: B vitamin intakes assessed by a semi-quantitative FFQ designed to measure the intake over the previous year were compared with those from 10 24HR, as well as to plasma levels of folate and vitamin B12, in randomly selected men (n=96) and women (n=99) aged 30-60 years. FFQ-based B-vitamin intakes were also compared with plasma levels of B-vitamins and with MTHFR 677C4T genotype in 878 men, aged 40-61 years. RESULTS: Intakes of vitamins B12 and riboflavin were similar, whereas folate and B6 intakes were 16-27% higher, as estimated by FFQ versus 24HR. Spearman correlation coefficients between the two methods ranged from 0.31 to 0.63 (all P

Dietary beta-carotene, vitamin C and E intake and breast cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC).

So far, studies on dietary antioxidant intake, including beta-carotene, vitamin C and vitamin E, and breast cancer risk are inconclusive. Thus, we addressed this question in the European Prospective Investigation into Cancer and Nutrition. During a median follow-up time of 8.8 years, 7,502 primary invasive breast cancer cases were identified. Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI). All analyses were run stratified by menopausal status at recruitment and, additionally, by smoking status, alcohol intake, use of exogenous hormones and use of dietary supplements. In the multivariate analyses, dietary intake of beta-carotene, vitamin C and E was not associated with breast cancer risk in premenopausal [highest vs. lowest quintile: HR, 1.04 (95% CI, 0.85-1.27), 1.12 (0.92-1.36) and 1.11 (0.84-1.46), respectively] and postmenopausal women [0.93 (0.82-1.04), 0.98 (0.87-1.11) and 0.92 (0.77-1.11), respectively]. However, in postmenopausal women using exogenous hormones, high intake of beta-carotene [highest vs. lowest quintile; HR 0.79 (95% CI, 0.66-0.96), P (trend) 0.06] and vitamin C [0.88 (0.72-1.07), P (trend) 0.05] was associated with reduced breast cancer risk. In addition, dietary beta-carotene was associated with a decreased risk in postmenopausal women with high alcohol intake. Overall, dietary intake of beta-carotene, vitamin C and E was not related to breast cancer risk in neither pre- nor postmenopausal women. However, in subgroups of postmenopausal women, a weak protective effect between beta-carotene and vitamin E from food and breast cancer risk cannot be excluded.

Plasma phyto-oestrogens and prostate cancer in the European Prospective Investigation into Cancer and Nutrition.

We examined plasma concentrations of phyto-oestrogens in relation to risk for subsequent prostate cancer in a case-control study nested in the European Prospective Investigation into Cancer and Nutrition. Concentrations of isoflavones genistein, daidzein and equol, and that of lignans enterolactone and enterodiol, were measured in plasma samples for 950 prostate cancer cases and 1042 matched control participants. Relative risks (RRs) for prostate cancer in relation to plasma concentrations of these phyto-oestrogens were estimated by conditional logistic regression. Higher plasma concentrations of genistein were associated with lower risk of prostate cancer: RR among men in the highest vs the lowest fifth, 0.71 (95% confidence interval (CI) 0.53-0.96, P trend=0.03). After adjustment for potential confounders this RR was 0.74 (95% CI 0.54-1.00, P trend=0.05). No statistically significant associations were observed for circulating concentrations of daidzein, equol, enterolactone or enterodiol in relation to overall risk for prostate cancer. There was no evidence of heterogeneity in these results by age at blood collection or country of recruitment, nor by cancer stage or grade. These results suggest that higher concentrations of circulating genistein may reduce the risk of prostate cancer but do not support an association with plasma lignans.

Plasma folate and total homocysteine levels are associated with the risk of myocardial infarction, independently of each other and of renal function.

OBJECTIVES: To investigate the relationship between plasma folate, vitamin B12 and total homocysteine concentrations, dietary intake of folate and vitamins B12, B6 and B2, and the risk of first acute myocardial infarction (MI). DESIGN: Nested case-referent study with up to 13 years of follow-up. SETTING: The population-based Northern Sweden Health and Disease Study, with 73 879 participants at the time of case ascertainment. SUBJECTS: A total of 571 MI cases (406 men) and 1569 matched referents. Of the cases, 530 had plasma samples available, and 247 had dietary B-vitamin intake data. RESULTS: Plasma concentrations of folate were inversely associated, and total homocysteine positively associated, with the risk of MI, independently of each other and of a number of established and novel cardiovascular risk factors, including renal function [multivariate odds ratio for highest vs. lowest quintile of folate 0.52 (95% CI 0.31-0.84), P for trend = 0.036, and homocysteine 1.92 (95% CI 1.20-3.09), P for trend = 0.006]. For plasma vitamin B12 concentrations, and vitamin B12, B6 and B2 intake, no clear risk relationship was apparent. Though not statistically significant, the results for folate intake were consistent with those for plasma concentrations. CONCLUSIONS: In this large prospective study of a population without mandatory folic acid fortification, both folate and homocysteine were strongly associated with the risk of myocardial infarction, independently of each other and of renal function. Although randomized trials of folic acid supplementation are needed to determine causality, our findings highlight the potential importance of folate, or sources of folate, in incident cardiovascular disease.

Bioavailability of selenium from bovine milk as assessed in subjects with ileostomy.

OBJECTIVE: To assess the absorption of dietary selenium in humans, especially of milk selenium. DESIGN: : 1-day meal studies in subjects with ileostomy. SETTING: Hospital outpatient clinics. SUBJECTS: Three subjects in the pilot study and nine subjects in the main study (eight men/ four women). INTERVENTION: Different beverages, 1 l/day, were given in addition to basal diets (soft drink, 1 week; low-fat milk, 3 weeks; fermented low-fat milk, 3 weeks and soft drink, 1 week). Ileostomy effluents were collected during the last 2 days in each of the four periods. RESULTS: On days when the subjects were given 1 l of low-fat milk, the estimated fractional absorption of total dietary selenium was 65.5 (2.3)% (mean (s.d.), n=18), which was similar to the value when fermented low-fat milk was given (64.1 (3.2)%). However, both the calculated amount of milk selenium absorbed (10.9 (2.4) vs 9.4 (1.7) microg selenium) and its fractional absorption (73.3 (16.1) vs 64.1 (11.2)%, n=18) were significantly higher for milk than for fermented milk. CONCLUSIONS: Selenium from milk and other sources is well absorbed in subjects with ileostomy. The real absorption may be even higher than the values shown.

Transrectal core biopsy trauma may increase cell proliferation in prostate tumors.

Whilst analyzing the morphological effects of a 3-week dietary intervention in patients with prostate cancer, we made an unexpected observation to the effect that prostate biopsy trauma may, at least transiently, increase prostate tumor cell proliferation. Further studies are needed to evaluate the clinical significance of this observation.

Rye bran and soy protein delay growth and increase apoptosis of human LNCaP prostate adenocarcinoma in nude mice.

BACKGROUND: In this study, we investigated whether dietary intervention could inhibit tumor growth of an androgen-sensitive human prostatic cancer. METHODS: LNCaP cells were transplanted subcutaneously in nude-mice. The animals were then put on different diets and tumor take, tumor growth and prostate specific antigen (PSA) secretion were studied during 9 weeks. RESULTS: Palpable tumors developed in 75% of the tumor-cell injected sites in animals fed a control diet (corn starch, sucrose, etc.) whereas, for animals given rye bran (RB), ethyl acetate extraction from rye bran supplemented cellulose based diets (CCEE), palpable tumors were seen in only 30% and for soy protein based diets (SCC) 50% of the transplantation sites, respectively. The tumors that grew to palpable size in the rye (RB) and soy (SCC) groups were smaller and secreted less PSA than those in the control group. In the rye and soy groups tumor cell apoptosis was increased, but cell proliferation was unaffected. Addition of fat to the rye diet reduced its effect on prostate cancer growth. CONCLUSIONS: Factors in rye bran and soy protein may inhibit prostate cancer growth. The effect is more apparent for rye than for soy. Further studies are needed to identify the effective substances and to explore the mechanism of action.

The protective effect of zinc on rosin and resin acid toxicity in human polymorphonuclear leukocytes and human gingival fibroblasts in vitro.

Combinations of rosin and zinc are used in dentistry as components of periodontal dressings and cements and as root canal sealers. The composition and properties of rosins differ largely depending on source and refinement processes. Rosin (colophony) is composed of approximately 70% resin acids. In order to study the toxic effects of different natural rosins and purified resin acids and the detoxifying effects of zinc, these compounds were analyzed and tested on human polymorphonuclear leukocytes (PMN cells) and human gingival fibroblasts using the radiochromium release method. The rosins and the pure resin acids showed a strong dose-related cytotoxicity, which was inhibited by increased zinc concentrations. The purified resin acids (isopimaric, levopimaric, and neoabietic acid) were more toxic than the natural rosins. The contents of these resin acids might explain the difference in toxicity of the rosins tested. It is concluded that rosin and zinc are not to be considered inert compounds and that the cytoprotective effects of zinc and its role in dentistry products merit further investigations.

Changes in blood manganese levels during pregnancy in iron supplemented and non supplemented women.

Blood manganese levels and iron status indices were determined each trimester in 66 healthy pregnant women. Twenty-five were randomly assigned to iron supplementation, 19 to placebo and 22 received dietary advise aimed at increasing their dietary intake of fibre. Iron supplemented women had significantly higher levels of blood haemoglobin compared to the levels of the two other groups, and higher serum ferritin levels compared to the placebo group. No significant difference in blood manganese levels was observed among the three groups of women. There was a significant increase in blood manganese levels from one trimester to the next, which was slightly more pronounced in non supplemented women. The median values in the three trimesters were 154 (range 79-360) nmol/L, 190 (range 98-408) nmol/L, and 230 (range 133-481) nmol/L, respectively. Pregnancy seems to change manganese status or otherwise influence manganese metabolism irrespective of iron status and iron supplementation.

Effects of oat and rye fractions on biliary and faecal bile acid profiles in Syrian golden hamsters (Mesocricetus auratus).

The effects of bran and starchy endosperm fractions of oat and rye on faecal weight and on biliary and faecal bile acids were studied in Syrian golden hamsters (Mesocricetus auratus). The animals fed on diets supplemented with steam-flaked oat bran, oat bran or rye bran had higher wet and dry weights of faeces compared with the animals fed on the fibre-free or low-fibre endosperm diets. A higher mean percentage of biliary cholic acid and a lower mean percentage of chenodeoxycholic and lithocholic (LCA) acids was observed in the bran-supplemented dietary groups. Animals fed on the bran-supplemented diets had increased daily faecal excretion of both total saponifiable and total free bile acids compared with the animals fed on fibre-free or endosperm-supplemented diets. The mean percentage of total saponifiable bile acids in the faeces was higher, and that of free bile acids lower in the animals fed on bran-supplemented diets. A significantly lower concentration of faecal free LCA was observed in the animals fed on the rye-bran diet. Both bran and endosperm diets reduced the faecal LCA:deoxycholic acid compared with the fibre-free diet, but the bran diets had a more pronounced effect than endosperm diets.

Effects on fibrinolytic activity of corn oil and a fish oil preparation enriched with omega-3-polyunsaturated fatty acids in a long-term study.

In addition to their beneficial effects in reducing platelet responsiveness, it has been a matter of controversy whether polyunsaturated fatty acids impair the fibrinolytic system or not. In a double-blind, parallel clinical trial, 40 subjects were randomized to treatment with 6 g/day of corn oil, or to 6 g/day of a fish oil preparation, enriched with omega-3-polyunsaturated fatty acids (2.0 g/day of omega-3-PUFA). Clinical and fibrinolytic variables were measured before and after 5 months of treatment. In the corn oil group, plasminogen activator inhibitor (PAI-1) decreased significantly but in the cod liver oil group, PAI-1 remained unchanged. Activities and mass concentrations of tissue plasminogen activator (t-PA) were unchanged in both groups. It is concluded that, in the doses given here, both these preparations have small or no effects on the fibrinolytic system.

A comparative study in rats of measures of the availability of dietary zinc and iron.

The purpose of this study was to compare three measures of the availability of dietary Zn and Fe in order to test their validity. Thirty-six 5-wk-old rats were fed deionized water and wheat crispbread made from endosperm flour, whole-grain flour, or endosperm flour supplemented with Zn and Fe to the whole-grain levels ad libitum for 14 d. The retention of 65Zn and 59Fe from test meals of the same breads after 1 wk and the sum of the excretion of endogenous Zn and Fe (injected 65Zn and 59Fe) with the Zn and Fe balances, respectively, were used as independent measures of Zn and Fe absorption. Measurements of Zn absorption, Zn balance, and serum Zn concentration gave quite different results with regard to the availability of Zn in the three breads, presumably because of the homeostatic regulation of the absorption and excretion of Zn when the Zn in the diet is in excess of the body's needs. Measurements of Fe absorption, Fe balance, and Fe concentrations in liver and serum were consistent in demonstrating overloading of Fe in the group given wheat-endosperm crispbread supplemented with Zn and Fe, but there was evidence that the isotope retention method overestimated iron absorption.

Coffee drinking and blood cholesterol--effects of brewing method, food intake and life style.

The strongest correlations between coffee consumption and serum cholesterol levels have been found in countries where people drink coffee brewed by mixing coffee grounds directly in boiling water (boiled coffee). In the present study of a population-based sample of 1625 middle-aged subjects (the Northern Sweden MONICA Study), approximately 50% of the participants were drinking boiled coffee, and 50% were drinking filtered coffee. Consumers of boiled coffee had significantly higher serum cholesterol levels than consumers of filtered coffee. Subjects who drank boiled coffee reported a higher intake of fat. A linear multiple regression analysis with serum cholesterol as the dependent variable confirmed that boiled coffee was an important independent determinant of cholesterol levels. We conclude that subjects who drink boiled coffee have higher serum cholesterol levels than those who drink filtered coffee, and that the most likely explanation for this finding lies in the type of brewing method.

The availability of zinc in endosperm, whole grain and bran-enriched wheat crispbreads fed to rats on a Zn-deficient diet.

The hypothesis that factors such as dietary fibre and phytate in wheat bran limit the availability of Zn was tested in growing rats fed on low-Zn diets with different wheat crispbreads as the major source of Zn. Six groups of six weanling male rats each were fed on 5 parts semi-synthetic Zn-deficient diet and 1 part wheat-endosperm crispbread for 1 week. At the beginning of the second week, the crispbread in the diet of five groups was exchanged for crispbread made using one of the following wheat flours: (1) whole grain, (2) bran-enriched whole grain, (3) endosperm with Zn added to the whole-grain level, (4) endosperm with Zn added to the bran-enriched level, (5) whole grain with Zn added to the bran-enriched level. These diets were given ad lib. together with deionized water for 2.5 weeks. The relative absorption of Zn was lowest from the three non-supplemented diets (75-82%). All the added Zn was absorbed. As appetite, body-weight increase, Zn absorption, Zn retention and the Zn concentrations in serum and bone differed only slightly among groups fed on diets with similar Zn concentrations, it is concluded that factors such as dietary fibre or phytate in wheat bran limit the availability of Zn in wheat crispbreads very little when all the Zn is needed for growth and development in rats.

Selenium, zinc, iron and copper levels in serum of patients with arterial and venous leg ulcers.

The total serum concentrations of selenium, zinc, iron and copper were determined in geriatric patients with and without leg ulcers. The levels of selenium, zinc and iron were significantly lower and the copper/zinc ratio was significantly higher in the leg ulcer group compared with control patients. The serum-copper level and the serum-copper/zinc ratio were raised in patients with poor ulcer healing.

Wound healing with adhesive zinc tape. An animal experimental study.

Wound healing was studied in rats given a diet with a subnormal zinc content (10 ppm). It is concluded that wound healing is impaired in the zinc deficient group compared with animals given a zinc-supplemented diet (150 ppm). Local supplementation of zinc with adhesive zinc tape treatment did not return wound healing to normal in the zinc deficient animals. Histological differences were observed between wounds treated with adhesive zinc tape and those treated with a gauze sponge. In particular, a more pronounced giant cell formation was observed in the gauze treated wound. Simultaneously these wounds showed peak activities of the alkaline phosphatases. A reduction of wound contraction was found in tape-treated wounds. A change in macrophage and fibroblast function during local zinc treatment is suggested. Some effects of wound healing on zinc metabolism are discussed.