Importance of both folic acid and vitamin B12 in reduction of risk of vascular disease

Fortification of food with folic acid to prevent neural-tube defects in babies also lowers plasma total homocysteine, which is a risk factor for vascular disease. We investigated the effect of folate and vitamin B12 on homocysteine concentrations. 30 men and 23 women received sequential supplementation with increasing doses of folic acid. After supplementation, the usual dependency of homocysteine on folate diminished, and vitamin B12 became the main determinant of plasma homocysteine concentration. This finding suggests that a fortification policy based on folic acid and vitamin B12, rather than folic acid alone, is likely to be much more effective at lowering of homocysteine concentrations, with potential benefits for reduction of risk of vascular disease.

Birthweight and aerobic fitness in adolescents: the Northern Ireland Young Hearts Project

The purpose of this study was to examine relationships between aerobic fitness and birthweight in adolescents. A representative cohort of 1015 males and females aged 12 and 15 y was studied, at baseline, with 89% of the 12-y-olds being re-examined 3 y later. The main outcome measures were an index of aerobic fitness, measured in laps completed at voluntary exhaustion by a twenty-metre shuttle run test, and recorded birthweight. Multiple linear regression, with and without adjustment for known and potential confounding variables, was performed to examine associations between fitness and birthweight. Birthweight and aerobic fitness were positively related so that for each kg decrease in birthweight, there was a mean (95% confidence interval) decrease in fitness score of 4.84 (0.35 to 9.33) laps and 3.21 (0.32 to 6.10) laps, in 12-y-old boys and girls respectively. This relationship is of a similar order to the strength of association between birthweight and adult blood pressure previously reported. Associations between birthweight and physical fitness at the age of 15 were weaker and were not significant. Our findings suggest that aerobic fitness may be involved in mediating the association between birthweight and cardiovascular disease risk later in life. The weakening of the association between birthweight and fitness between the ages of 12 and 15 y is similar to the weaker associations between birthweight and blood pressure seen among adolescents compared to younger children. We are currently re-examining this cohort to see if, as with blood pressure, the association with fitness re-emerges at an older age.

The efficacy and safety of nutritional supplement use in a representative sample of adults in the North/South Ireland Food Consumption Survey

OBJECTIVE

To describe the current use of nutritional supplements and their contribution to micronutrient intakes in a representative sample of Irish adults, to evaluate the impact of supplement use on the adequacy of micronutrient intakes and to assess the risk to supplement users of exceeding tolerable upper intake levels (UL).

STUDY DESIGN AND SUBJECTS

Food intake data were collected in 1379 (662 male and 717 female) randomly selected Irish adults aged 18 to 64 years using a 7-day food diary. The current use of nutritional supplements was assessed using a self-administered questionnaire and respondents entered each supplement as it was consumed into the food diary.

RESULTS

Twenty-three per cent of respondents regularly used nutritional supplements. Twice as many women used supplements as men. The intakes of micronutrients were significantly higher (P<0.001) in supplement users than in non-users. Micronutrient intakes from food sources were similar in male users and non-users of supplements, but were significantly higher (P<0.01) in female users, by 3 to 13%, for Fe, Mg, Mn, vitamins C and E and niacin than in non-users. The percentage of female users between 18 and 50 years who had mean Fe intakes below the average requirement (AR) (10 mg) decreased from 50 to 25 when the contribution from supplements was included. The use of supplements reduced the percentage of men who had mean intakes below the AR for Zn from 19 to 13, for riboflavin from 14 to 6 and for vitamin A from 20 to 5, and reduced the percentage of women with intakes below the AR for Ca from 23 to 16 and for riboflavin from 23 to 14. Twenty-one women out of 80 aged between 18 and 50 years, who consumed supplemental folate, achieved the intake of 600 microg recommended to prevent neural tube defects. Twenty-two per cent of the women who took iron and 15% of the women who took vitamin B6 in supplemental form had mean daily intakes that exceeded that UL for these nutrients. Supplement users did not exceed the UL for the other micronutrients.

CONCLUSIONS

Supplementation appears to be beneficial in promoting adequate intakes of some micronutrients, particularly Fe and folate in women aged 18-50 years and vitamin A in men. There appears to be little risk to supplement users of experiencing adverse side effects due to excessive intakes of micronutrients.

The North/South Ireland Food Consumption Survey: mineral intakes in 18-64-year-old adults

OBJECTIVE

To measure mineral intakes and the contribution of different food groups to mineral intakes in adults aged 18-64 years in Ireland. Intakes are reported for Ca, Mg, P, Fe, Cu and Zn. The adequacy of mineral intakes in the population and the risk of occurrence of excessive intakes are also assessed.

DESIGN

Food consumption was estimated using a 7-day food diary for a representative sample (n=1379; 662 men, 717 women) of 18-64-year-old adults in the Republic of Ireland and Northern Ireland selected randomly from the electoral register. Mineral intakes (Ca, Mg, P, Fe, Cu and Zn) were estimated using tables of food composition.

RESULTS

Mean nutrient density of intakes was higher for women than men for Ca and Fe and increased with age for all minerals, except Ca for men and Fe for women. Meat and meat products were the major contributor to mean daily intakes of Zn (38%), P (23%), Fe (18%), Cu (15%) and Mg (13%); dairy products (milk, yoghurt and cheese) to Ca (44%), P (22%), Zn (14%) and Mg (11%); bread and rolls to Fe (21%), Cu (18%), Ca and Mg (17%), Zn (13%) and P (12%); potatoes and potato products to Cu (16%), Mg (14%) and Fe (10%); and breakfast cereals to Fe (13%). In women of all ages nutritional supplements contributed 7.6%, 4.4%, 3.6% and 2.2% of mean daily intake of Fe, Zn, Cu and Ca, respectively, while in men of all ages, nutritional supplements contributed 2.7%, 2.3%, 1.7% and 0.6%, respectively, to mean daily intakes of Fe, Zn, Cu and Ca. Adequacy of minerals intakes in population groups was assessed using the average requirement (AR) as a cut-off value. A significant prevalence of intakes below the AR was observed for Ca, Fe, Cu and Zn but not P. A higher proportion of women than men had intakes below the AR for all minerals. Almost 50% of 18-50-year-old females had intakes below the AR for Fe, while 23%, 23% and 15% of women of all ages had intakes below the AR for Ca, Cu and Zn, respectively. For men of all ages, 11%, 8% and 13% had intakes below the AR for Ca, Cu and Zn, respectively. There appears to be little risk of excessive intake of Ca, Mg, P, Cu or Zn in any age/sex category. However, 2.9% of women of all ages had intakes above the tolerable upper intake level for Fe (45 mg) due to supplement use.

CONCLUSION

Almost 50% of women aged 18-50 years had Fe intakes below the AR and relatively high proportions of women of all ages had intakes below the AR for Ca, Cu and Zn. With the possible exception of iron intake from supplements in women, there appears to be little risk of excessive intake of minerals in the adult population. Meat and meat products, dairy products (milk, cheese and yoghurt), bread and rolls, potatoes and potato products and breakfast cereals are important sources of minerals; nutritional supplements make only a small contribution to mineral intakes in the population as a whole but may contribute significantly to intakes among supplement users.

Determination of an acute no-observed-adverse-effect level (NOAEL) for copper in water

A prospective, double-blind controlled study was designed to determine the acute no-observed-adverse-effect level (NOAEL) of nausea in an apparently healthy population of 179 individuals who drank copper-containing water as the sulfate salt. Subjects were recruited at three different international sites and given a blind, randomly selected dose (0, 2, 4, 6, or 8 mg Cu/L) in a bolus of 200 ml (final total copper dose was equivalent to 0, 0.4, 0.8, 1.2, and 1.6 mg) once weekly over a consecutive 5-week period. Gastrointestinal (GI) symptoms of nausea, abdominal pain, vomiting, or diarrhea were screened for a period of up to 24 h. Nausea was the most frequently reported effect and was reported within the first 15 min of ingestion. For the combined trisite population (n=179), 8, 9, 14, 25, and 44 subjects responded positively to one or more GI symptoms at 0, 2, 4, 6, and 8 mg Cu/L, respectively. Analysis of the data demonstrated a clear dose response to the combined positive GI effects and to nausea alone. Statistically significant greater reporting of effects occurred at 6 and 8 mg Cu/L. Therefore, an acute NOAEL and lowest-observed-adverse-effect level of 4 and 6 mg Cu/L (0.8 and 1.2 mg Cu), respectively, were determined in drinking water for a combined international human population.

The North/South Ireland Food Consumption Survey: vitamin intakes in 18-64-year-old adults

OBJECTIVE

To estimate vitamin intakes and assess the contribution of different food groups to vitamin intakes in adults aged 18-64 years in Ireland as estimated in the North/South Ireland Food Consumption Survey. Intakes are reported for retinol, carotene, total vitamin A, vitamin D, vitamin E, thiamin, riboflavin, pre-formed niacin, total niacin equivalents, vitamin B6, vitamin B12, folate, biotin, pantothenate and vitamin C. The adequacy of vitamin intakes in the population and the risk of occurrence of excessive vitamin intakes are also assessed.

DESIGN

Food consumption was estimated using a 7-day food diary for a representative sample (n=1379; 662 men and 717 women) of 18-64-year-old adults in the Republic of Ireland and Northern Ireland selected randomly from the electoral register. Vitamin intakes were estimated using tables of food composition.

RESULTS

In general, the percentage of the population with vitamin intakes below the average requirement (AR) was low. Mean daily intake of total vitamin A was below the AR in 20.2% and 16.6% of men and women, respectively, and mean daily intake of riboflavin was below the AR in 12.5% and 20.6% of men and women, respectively. Mean daily folate intakes were below the AR for folate in 11.2% and 6.6% of women aged 18-35 years and 36-50 years, respectively. Only 2.2% of women aged 18-35 years and 5.2% of women aged 36-50 years achieved the recommended folate intake of 600 microg day(-1) for women of reproductive age for the prevention of neural tube defects. A high proportion of the population has a low dietary vitamin D intake and is largely dependent on sunlight exposure to maintain adequate vitamin D status. Except for pre-formed niacin, the 95th percentile intake of vitamins did not exceed the tolerable upper intake level (UL) for any group and was much less than the UL for most vitamins. Although 20.8% of men and 6.3% of women exceeded the UL for pre-formed niacin (which is 35 mg, based on nicotinic-acid-induced flushing), the large contribution of meat and fish to the intake of niacin (as nicotinamide) suggests that the risk of overexposure to nicotinic acid is much lower than this and is probably solely related to supplement use. A small proportion of men (4.0%) and women (1.2%) aged 51-64 years had retinol intakes that exceeded the UL (3000 microg) and while the 95th percentile intake of women in the 18-50 year age group was well below the UL, 1.5% of 18-35-year-old and 2.4% of 36-50-year-old women had mean daily retinol intakes above the UL. About 2.0% of women had intakes of vitamin B6 that exceeded the UL (25 mg). There were significant differences by age and sex in nutrient densities of vitamin intakes between men and women and between age groups, which may be explained by differences in consumption of particular food groups as well as different patterns of supplement use.

CONCLUSION

Nutritional adequacy of the population for most vitamins was good. Folate intake in women of childbearing age is not meeting current recommendations for the prevention of neural tube defects. The public health significance of the relatively high proportion of men and women with inadequate intakes of vitamin A and riboflavin and with low dietary intakes of vitamin D is unclear and should be investigated further. With the possible exception of niacin (flushing) and vitamin B6 (neuropathy), there appears to be little risk of the occurrence of adverse effects due to excessive consumption of vitamins in this population, based on current dietary practices.

Cultural collisions at the bedside: social expectations and value triage in medical practice

As early as 1981 Gorlin and Zucker produced a film, A Complicating Factor: Doctors' Feelings as a Factor in Medical Care and in a 1983 paper on the subject they described one of the important epiphenomena of the encounter between doctor and patient—namely, the reaction of the physician to the patient and how this affects both the physician and the quality of the relationship. At that time they were concerned with the physicians' ability to reckon with their own reactions to patients who presented with problems or personality traits that complicated the doctor-patient relationship. Some patients were hateful or unlikable, some denied their disease state, some became unusually dependent on the physician, some were intimidating to the doctor. Their behavior evoked responses that tended to complicate the doctor-patient relationship with distancing, unusual identification, or hostility. That publication recognized and explained the problem and went on to suggest a process of achieving emotional awareness and mastery to help physicians maintain their appropriate role.

Plasma homocysteine is not subject to seasonal variation

BACKGROUND

Studies investigating the relationship between plasma total homocysteine (tHcy) and vascular disease usually rely on a single measurement. Little information is available, however, on the seasonal variability of plasma tHcy. The aim of this study was to investigate the seasonal variation in fasting plasma tHcy and related B-vitamin intake and status in a group of people who did not consume fortified foods or take B-vitamin supplements.

METHODS

In this longitudinal study, a group of 22 healthy people were followed for 1 year. A fasting blood sample and dietary information were collected from each individual every 3 months, i.e., at the end of each season.

RESULTS

There was no significant seasonal variation in plasma tHcy or in B-vitamin intake or status with the exception of red cell folate (significantly lower in spring compared with autumn or winter) and serum folate (significantly lower in spring compared with the other seasons). Although the between-person variation in plasma tHcy was high (47%), the within-person variation was low (11%). This low variation, combined with the low methodologic imprecision of 3.8%, yielded a high reliability coefficient for plasma tHcy (0.97).

CONCLUSIONS

Although there was a small seasonal variation in folate status, there was no corresponding seasonal variation in plasma tHcy. The high reliability coefficient for plasma tHcy suggests that a single measurement is reflective of an individual's average plasma tHcy concentration, thus indicating its usefulness as a potential predictor of disease. This, however, needs to be confirmed in different subgroups of the population.

Cardiac drug and psychotropic drug interactions: significance and recommendations

Understanding cardiac drug interactions with concurrent psychotropic prescriptions is essential for the practicing cardiologist, primary care physician, and psychiatrist. There has been an explosion in the use of new drugs in both psychiatry and cardiology without widespread knowledge of their potential interactions. The increasing tendency toward polypharmacy, the use of psychotropic medications by cardiologists and primary care physicians caring for cardiac patients, and the growth of the aging population present major challenges for the practitioner. Finally, there is a need to have models and paradigms for predicting potential drug interactions-the cytochrome P450 schema. This article describes a method to identify, understand, and codify the interactions between psychotropic and cardiac drugs, a systematic approach for updating this key database, and specific cardiac-psychotropic drug interactions. Specifically, this paper 1) details the interactions, 2) addresses the level of their clinical significance, 3) describes the potential mechanism(s) of the interactions, and 4) offers recommendations to the clinician (Appendix). Because the majority of the original clinical trials, either for cardiac medications or for psychotropic drugs, did not include studies comparing these two drug domains contemporaneously, their interactions often become known only with their combined use in the clinical arena, using the patient as "guinea pig" and through subsequent reporting.

No effect of copper supplementation on biochemical markers of bone metabolism in healthy young adult females despite apparently improved copper status

OBJECTIVE

To investigate the effects of increasing Cu intakes, above the usual dietary intake, on biomarkers of bone metabolism in healthy young adult females (aged 21-28 y) over a 4 week period.

DESIGN

A double-blind, placebo-controlled randomised repeat crossover Cu supplementation trial.

SETTING

The study was conducted at the Royal Veterinary and Agricultural University (RVAU), Copenhagen, Denmark.

SUBJECTS

Sixteen healthy young adult females aged 20-28 y were recruited from among students at the RVAU.

INTERVENTION

During the 4 week intervention periods in this randomised, crossover trial (3x4 weeks with a minimum 3 week wash-out period), each subject received, in addition to their usual diet, either 3 or 6 mg elemental Cu/day as CuSO4 or a matching placebo. On the last 3 days of each dietary period 24 h urines were collected. In addition, blood was collected on the last day of each dietary period.

RESULTS

Serum Cu and erythrocyte superoxide dismutase (but not caeruloplasmin protein concentration or activity (putative indices of Cu status)) were significantly increased (P<0.05) after daily Cu supplementation with 3 and 6 mg/day for 4 weeks. Serum osteocalcin (biomarker of bone formation), urinary creatinine (Cr) concentration, urinary pyridinoline (Pyr)/Cr or deoxypyridinoline (Dpyr)/Cr excretion, or daily urinary Pyr or Dpyr excretion (biomarkers of bone resorption) were unaffected by Cu supplementation.

CONCLUSION

Copper supplementation of the usual diet in healthy young adult females, while apparently improving Cu status, had no effect on biochemical markers of bone formation or bone resorption over 4 week periods.

SPONSORSHIP

Funding from the European Commission.

Low-dose vitamin B-6 effectively lowers fasting plasma homocysteine in healthy elderly persons who are folate and riboflavin replete

BACKGROUND

Current data suggest that physiologic doses of vitamin B-6 have no significant homocysteine-lowering effect. It is possible that an effect of vitamin B-6 was missed in previous trials because of a much greater effect of folic acid, vitamin B-12, or both.

OBJECTIVE

The aim of this study was to investigate the effect of low-dose vitamin B-6 supplementation on fasting total homocysteine (tHcy) concentrations in healthy elderly persons who were made replete with folate and riboflavin.

DESIGN

Twenty-two healthy elderly persons aged 63-80 y were supplemented with a low dose of vitamin B-6 (1.6 mg/d) for 12 wk in a randomized, double-blind, placebo-controlled trial after repletion with folic acid (400 microg/d for 6 wk) and riboflavin (1.6 mg/d for 18 wk); none of the subjects had a vitamin B-12 deficiency.

RESULTS

Folic acid supplementation lowered fasting tHcy by 19.6% (P < 0.001). After folic acid supplementation, baseline tHcy concentrations ranged from 6.22 to 23.52 micromol/L and 10 subjects had suboptimal vitamin B-6 status (plasma pyridoxal-P < 20 nmol/L). Two-way analysis of variance showed that the significant improvement in vitamin B-6 status in response to vitamin B-6 supplementation (on the basis of both pyridoxal-P: and the erythrocyte aspartate aminotransferase activation coefficient) was reflected in a significant reduction in plasma tHcy of 7.5%.

CONCLUSIONS

Low-dose vitamin B-6 effectively lowers fasting plasma tHcy in healthy subjects who are both folate and riboflavin replete. This suggests that any program aimed at the treatment or prevention of hyperhomocysteinemia should include vitamin B-6 supplementation.

Genetic Aspects of Nutrition and Toxicology: Report of a Workshop

The health and resilience of humans and animals is, in large part, determined by the quality and quantity of the diet. This, in turn, may influence an individual's capability to deal with stress including toxic insult. In addition, there may be specific components of the diet that modulate the toxicity of specific toxicants whether the latter are ingested as food or absorbed via other routes. Many examples attest to the importance of interactions between dietary components and toxicants after absorption in the body. Such interactions occur at every level of biological organization from the molecular to the whole organism. Some may be synergistic, others antagonistic. Some may involve direct chemical reaction between the nutrient molecule and the toxicant, others may occur by indirect action at the cellular or organ levels. All examples point to the importance of considering diet when measuring the response to toxic agents whether in animals or humans. In order to foster interaction between the sciences of nutrition and toxicology, The Heinz Institute of Nutritional Sciences as sponsoring a series of workshops. The first of these was held in June, 1999 at the University of Ulster to address evolutionary aspects of nutrition--toxicology (for report see Eur. J. Nutr, 39, 49-52, 2000). In June, 2000, a second workshop was held at the University of Toronto to address genetic aspects, and this is a brief summary of the proceedings. We are beginning to understand the molecular basis of the regulation of gene expression by dietary factors and how genetic changes can affect response to toxicants. Recent advances in technology and a detailed understanding of disease etiology has led to the ability to study molecular determinants of disease risk. The workshop provided a forum for nutritionists, toxicologists, molecular biologists, epidemiologists and others to discuss common interests and to merge their efforts towards an integrated approach to nutrition--toxicology via genetics and genomics. The first session dealt with the mechanism by which nutrients such as fatty acids (Clarke), amino acids (Jefferson) and metal ions (Cousins) can regulate gene expression. In the second session, there were presentations on the effects of nutritional factors on genes of toxicological significance such as phase I and phase II enzymes of drug metabolism (Guengerich, Goodfellow and Grant) as well as on oxidative DNA damage and its repair (Collins, Weindruch). Session three dealt with gene-nutrient interactions in the development of chronic diseases such as diabetes (Hegele, Berdanier) and cancer (Kim, Ambrosone et al.). New developments such as DNA microarrays (McGlynn) and the use of transgenic and knockout models (Sehayek) were presented in the final session.

Bioavailability of n-3 polyunsaturated fatty acids (PUFA) in foods enriched with microencapsulated fish oil

OBJECTIVE

Incorporation of fish oil into food products provides a means of increasing n-3 fatty acid intake, particularly in populations where fish consumption remains low. The aim of the present study was to evaluate the bioavailability of n-3 PUFA in microencapsulated fish-oil-enriched foods compared with an equal amount of n-3 PUFAs contained in fish oil capsules.

METHODS

Twenty-five healthy female volunteers were randomly assigned to one of two groups for the 4-week intervention: one group received 0.9 g of n-3 PUFA/day as fish oil capsule (capsule group), while the second group (food group) received an equal amount of n-3 PUFA/day from enriched foods. Baseline and post-intervention samples were analysed for platelet fatty acid composition.

RESULTS

There was no significant difference in the change in platelet arachidonic acid (AA), eicosapentaenoic acid (EPA), or docosahexaenoic acid (DHA) between the two groups following the intervention.

CONCLUSIONS

The results indicate that n-3 PUFA from microencapsulated fish-oil-enriched foods are as bioavailable as n-3 PUFA in a capsule. Fortification of foods with microencapsulated fish oil, therefore, offers an effective way of increasing n-3 PUFA intakes and status in line with current dietary recommendations.

Socio-economic position and coronary heart disease risk factors in youth. Findings from the Young Hearts Project in Northern Ireland

BACKGROUND

This study investigates the existence of socioeconomic differentials in behavioural and biological risk factors for coronary heart disease in young people from Northern Ireland, taking into account differences in biological maturation.

METHODS

A school-based prospective study, with measurements in 1989/1990 and 1992/1993. Socio-economic position was based on occupational level of the main family breadwinner. Behavioural risk factors included were physical inactivity, the intake of total energy, dietary fat and a number of micronutrients. Biological risk factors included were blood pressure, body fatness, lipoproteins and cardio-pulmonary fitness. Biological maturation was based on Tanner's stages.

PARTICIPANTS

251 boys and 258 girls who were measured at the age of 12 years and re-examined at the age of 15 years.

RESULTS

Cross-sectional analyses showed that socio-economic differences in cholesterol intake (in boys) and physical inactivity and total energy intake (in girls) were present at 12 and 15 years of age, while differences in fat and fruit intake and smoking behaviour (in boys and girls) became established at the age of 15 years, with unfavourable levels in subjects in the manual group. Longitudinal analyses confirmed that differences in behavioural risk factors exist or develop during adolescence. No clear pattern of differences in biological risk factors was found by socio-economic position. Adjustment for biological maturation did not materially alter the results.

CONCLUSION

Differences in lifestyle by socio-economic position seem to become established in adolescence. These differences however, are not (yet) reflected in differences in biological risk factors by socio-economic position.

Fitness, fatness, and coronary heart disease risk in adolescents: the Northern Ireland Young Hearts Project

PURPOSE

The purpose of this study was to examine the independence and relative strengths of association between coronary heart disease (CHD) risk status and both body fatness and cardiorespiratory (C-R) fitness in 12- and 15-yr-old adolescents.

METHODS

The study cohort consisted of 1015 schoolchildren aged 12 and 15 yr (251 12-yr-old boys, 258 12-yr-old girls, 252 15-yr-old boys, and 254 15-yr-old girls), representing a 2% random sample of each population group. For each child, height, weight, sexual maturity (pubertal status), skin-fold thicknesses (4 sites), blood pressure (random zero sphygmomanometer), nonfasting serum total, and high density lipoprotein (HDL)-cholesterol and C-R fitness (20-m shuttle run; 20-MST) were determined under standardized conditions. Socioeconomic status and habitual physical activity were also determined from questionnaire information. Multiple regression analyses were carried out to examine relationships between five CHD risk factors, and fitness and fatness and to examine the relative strengths of fitness and fatness on CHD risk status, correcting for potential confounding variables.

RESULTS

Our main findings were: 1) Relationships between fatness and CHD risk factors are invariably stronger than between fitness and the same risk factors. For example, partially adjusted standardized regression coefficients for 12-yr-old boys revealed significant relationships between all five CHD risk factors and fatness, compared with three of five for fitness. The corresponding figures for 12-yr-old girls were three of five (fatness) and one of five (fitness). Broadly similar results were apparent for 15-yr-olds. 2) Although relationships between fitness and CHD risk factors do not survive further adjustment for fatness, the relationships between fatness and CHD risk are more robust and are unaffected by further adjustment for fitness.

CONCLUSION

Our results indicate that the observed relationships between C-R fitness and CHD risk status in adolescents are mediated by fatness, whereas the observed relationships with fatness are independent of fitness. Primary prevention of CHD during childhood should therefore concentrate upon preventing or reversing undue weight gain.

Effect of supplemental methionine on plasma homocysteine concentrations in healthy men: a preliminary study

Hyperhomocysteinaemia is an established risk factor for vascular disease. The only source of homocysteine in humans is the amino acid methionine found in dietary protein. In an 8-week study, fasting plasma homocysteine concentrations were examined in a group of healthy male subjects (n = 6) under usual dietary conditions (weeks 1-4) and in response to weekly graded (25, 50 and 75 mg/kg/d) supplementary methionine (weeks 5, 6, 7). Nutrient intakes, including methionine, were calculated from 4 x 3 day food records. Under usual dietary conditions (mean methionine intake; 0.95 +/- 0.51 mg/d) weekly mean plasma homocysteine concentrations for the group were not significantly different (ANOVA) from each other ranging from 6.82 +/- 1.77 to 9.42 +/- 2.73 mumol/l. Doubling (supplementing with 25 mg/kg/d; + 2.04 g/d) or quadrupling (50 mg/kg/d; + 4.08 g/d) methionine intakes did not result in a significant increase in plasma homocysteine (8.56 +/- 3.68 mumol/l and 13.37 +/- 5.09 mumol/l respectively). A significant increase, however, was achieved when diets were supplemented with methionine at the highest level of 75 mg/kg/d (+6.14 g/d) resulting in a mean plasma homocysteine concentration of 18.05 +/- 11.8 mumol/l. Mean plasma homocysteine concentration returned to baseline (8.76 +/- 3.42 mumol/l), 10 days post-supplementation. The results of this study indicate that an increased dietary methionine will only cause elevated fasting homocysteine concentrations if ingested at intakes equivalent to five times usual intake. Because it is very unlikely that such levels could be achieved through dietary means alone we conclude that plasma homocysteine is unlikely to be affected by longer-term changes in food methionine intake.

Copper supplementation in humans does not affect the susceptibility of low density lipoprotein to in vitro induced oxidation (FOODCUE project)

The oxidative modification of low-density lipoprotein cholesterol (LDL) has been implicated in the pathogenesis of atherosclerosis. Copper (Cu) is essential for antioxidant enzymes in vivo and animal studies show that Cu deficiency is accompanied by increased atherogenesis and LDL susceptibility to oxidation. Nevertheless, Cu has been proposed as a pro-oxidant in vivo and is routinely used to induce lipid peroxidation in vitro. Given the dual role of Cu as an in vivo antioxidant and an in vitro pro-oxidant, a multicenter European study (FOODCUE) was instigated to provide data on the biological effects of increased dietary Cu. Four centers, Northern Ireland (coordinator), England, Denmark, and France, using different experimental protocols, examined the effect of Cu supplementation (3 or 6 mg/d) on top of normal Cu dietary intakes or Cu-controlled diets (0.7/1.6/6.0 mg/d), on Cu-mediated and peroxynitrite-initiated LDL oxidation in apparently healthy volunteers. Each center coordinated its own supplementation regimen and all samples were subsequently transported to Northern Ireland where lipid peroxidation analysis was completed. The results from all centers showed that dietary Cu supplementation had no effect on Cu- or peroxynitrite-induced LDL susceptibility to oxidation. These data show that high intakes (up to 6 mg Cu) for extended periods do not promote LDL susceptibility to in vitro-induced oxidation.

Frequency of fruit and vegetable consumption and blood antioxidants in the Caerphilly cohort of older men

OBJECTIVE

To assess the number of portions of fruit and vegetables consumed daily by a large representative sample of older men, and to determine how blood antioxidant (vitamins E, A and carotenoids) concentrations vary with fruit and vegetable consumption.

DESIGN

Cross-sectional study of free-living men.

SUBJECTS

Men aged 55-69 y (dietary data, n=1957; blood data, n=1874) participating in Phase III (1989-1993) of the Caerphilly and Speedwell Collaborative Heart Disease Studies.

METHODS

Dietary data were obtained by semi-quantitative food-frequency questionnaire and blood samples were analysed for antioxidant vitamins. Men were subdivided into groups on the basis of portions per day of fruit and vegetables. Within these sub-groups, mean and 95% ranges of intakes and of blood antioxidant levels were obtained. Log transformations were performed where appropriate.

RESULTS

Only 4.3% of the men met the recommended target of five portions, while 33.3% of the men consumed one or fewer portions of fruit and vegetables per day. Those men who consumed the poorest diets with respect to fruit and vegetable intakes were more likely to be from lower socio-economic classes, drink more alcohol and be current smokers. Fruit and vegetable intake reflected plasma concentrations of antioxidants, which showed a dose-response relationship to frequency of consumption.

CONCLUSIONS

Older men in the UK consume much less fruit and vegetables than current recommendations. Major difficulties are likely to be encountered in trying to meet a dietary target that is clearly much higher than the fruit and vegetable consumption of large sections of the older population in the UK.

SPONSORSHIP

This work was supported by the Medical Research Council.

Fluctuations in dietary methionine intake do not alter plasma homocysteine concentration in healthy men

A moderate elevation in plasma total homocysteine (tHcy) has been established as an independent risk factor for vascular disease. An important exogenous source of homocysteine is methionine found in foods rich in animal protein. We investigated the response of tHcy to fluctuations in methionine intake in a cross-over intervention trial (two arms). Healthy men (n = 52; 19-29 y) were screened for habitual methionine intake using a food-frequency questionnaire. Subjects in the top quartile for methionine intake (n = 13), with a baseline fasting tHcy of 7.01 +/- 1.84 micromol/L (mean +/- SD), were randomly assigned to receive either a low-methionine intervention diet for 1 wk followed by a control diet for 1 wk or vice-versa. Simultaneously, those in the bottom quartile for methionine intake (n = 11), with a fasting plasma tHcy of 9.79 +/- 7. 20 micromol/L (mean +/- SD), received either a high methionine intervention diet for 1 wk followed by a control diet or vice-versa. All subjects had serum folate, red-cell folate, serum vitamin B-12 and plasma pyridoxal phosphate (PLP) concentrations within normal ranges. During the intervention, subjects in the top quartile for methionine intake reduced their daily methionine intake 79%, from 1969 +/- 639 to 407 +/- 83 mg/d (P: </= 0.001), and those in the bottom quartile almost doubled their methionine intake, from 1155 +/- 401 to 2112 +/- 379 mg/d (P: </= 0.001). Despite these changes in methionine intake, no corresponding changes in plasma tHcy were observed. These results suggest that in the absence of an obvious deficiency of relevant B-vitamins, fasting plasma tHcy is unaffected by intermediate-term fluctuations (up to 100% of usual intake) in dietary methionine.

Tracking of nutrient intakes in adolescence: the experiences of the Young Hearts Project, Northern Ireland

This study evaluated the tracking of energy and nutrient intakes, assessed by diet history, in a random sample of adolescents (boys n 225, girls n 230) at baseline (age 12 years), and subsequently at age 15 years. Median energy (MJ/d) and macronutrient (g/d) intakes increased significantly (all P < 0.001) with increasing age in the boys. The girls' reported energy intake (MJ/d) remained stable over time, despite significant increases in BMI, weight and % body fat. Age-related changes in the girls' macronutrient intakes were inconsistent. When expressed in terms of nutrient density, the diets of both sexes became significantly richer, over time, in total folate (both sexes, P < 0.01), but poorer in Ca (boys P < 0.01, girls P < 0.001) and riboflavin (both sexes P < 0.001). Vitamin B6 (P < 0.001) and Fe (P < 0.05) densities increased in the boys, while the thiamin density of the girls' diets decreased (P < 0.001). Tracking, defined as maintenance of rank over time, was summarised using weighted kappa statistics (kappa). There were some significant changes in intakes at the group level; however, tracking of energy and nutrients in both sexes was only poor to fair (kappa < 0.40), indicating substantial drift of individuals between classes of intake over time. Particularly poor tracking was evident for % energy from sugars (kappa 0.09) and total fat (kappa 0.09) in the girls' diets. In conclusion, the poor to fair tracking observed in this cohort suggests that individual dietary patterns exhibited at 12 years of age are unlikely to be predictive of energy and nutrient intake at age 15 years.

Interactions between vitamins C and E in human subjects

Despite convincing in vitro evidence, a vitamin C-E interaction has not been confirmed in vivo. This study was designed to examine the effects of supplementation with either vitamin C or E on their respective plasma concentrations, other antioxidants, lipids and some haemostatic variables. Fasting blood was collected before and after intervention from thirty healthy adults in a double-blinded crossover study. Baselines for measured variables were established after 2 weeks of placebo supplementation, followed by daily supplementation with 73.5 mg RRR-alpha-tocopherol acetate or 500 mg ascorbic acid, and placebo, for 6 weeks. A 2 month washout preceded supplement crossover. Mean values showed that plasma lipid standardised alpha-tocopherol increased with ascorbic acid supplementation: from 4.09 (sem 0.51) to 4.53 (sem 0.66) micromol/mmol total cholesterol plus triacylglycerol (P < 0.05), and plasma ascorbic acid increased from 62.8 (sem 14.9) to 101.3 (sem 22. 2) micromol/l (P < 0.005). Supplementation with (RRR)-alpha-tocopherol acetate increased plasma alpha-tocopherol from 26.8 (sem 3.9) to 32.2 (sem 3.8) micromol/l (P < 0.05), and lipid-standardised alpha-tocopherol from 4.12 (sem 0.48) to 5.38 (sem 0.52) micromol/mmol (P < 0.001). Mean plasma ascorbic acid also increased with vitamin E supplementation, from 64.4 (sem 13.3) to 76. 4 (sem 18.4) micromol/l (P < 0.05). Plasma ferric reducing (antioxidant) power and glutathione peroxidase (U/g haemoglobin) increased in both groups, while urate, total cholesterol and triacylglycerol levels decreased (P < 0.05 throughout). Results are supportive of an in vivo interaction between vitamins C and E.

The effect of low-dose fish oil supplementation on serum growth factors in healthy humans

OBJECTIVE

To examine the effect of low-dose fish oil supplementation on specific growth factors, purported to play a central role in lesion formation, and also on the total growth factor activity of serum, as assessed by the induction of DNA synthesis in cultured human arterial smooth muscle cells.

DESIGN

Randomized placebo-controlled double-blind intervention study.

SETTING

Free-living population.

SUBJECTS

Sixty-three healthy volunteers, 37 males and 26 females.

INTERVENTIONS

Four treatment regimes with subjects receiving 0, 0.3,0.6 or 0.9 g/day of n-3 PUFA for an 8 week period. Blood samples were taken at baseline and following the 8 week intervention. All samples were analysed in batch following completion of the study.

RESULTS

Consumption of fish oil had no effect on serum platelet-derived growth factor (PDGF), or transforming growth factor beta (TGFbeta) concentration. Furthermore, fish oil supplementation did not alter the total growth factor activity of serum.

CONCLUSIONS

Results indicate that low-dose fish oil supplementation, equivalent to about two portions of fatty fish per week and providing less than 1 g n-3 PUFA/day, does not alter the levels of the major serum growth factors and does not modify total serum growth factor activity in healthy human volunteers.

SPONSORSHIP

European Union shared cost project (FAIR-CT-95-0085).

Response of putative indices of copper status to copper supplementation in human subjects

No sensitive functional index is currently available to assess Cu status in healthy human populations. This study evaluated the effect of Cu supplementation on putative indices of Cu status in twelve women and twelve men, aged between 22 and 45 years, who participated in a double-blind placebo controlled crossover study. The study consisted of three 6-week supplementation regimens of 3 mg CuSO4, 3 mg Cu-glycine chelate and 6 mg Cu-glycine chelate, each separated by placebo periods of equal length. Women had significantly higher caeruloplasmin oxidase activity (P < 0.001), caeruloplasmin protein concentration (P < 0.05), and serum diamine oxidase activity (P < 0.01) at baseline than men. Erythrocyte and leucocyte superoxide dismutase activity, leucocyte cytochrome c oxidase activity, and erythrocyte glutathione peroxidase activity did not respond to Cu supplementation. Platelet cytochrome c oxidase activity was significantly higher (P < 0.01), after supplementation with 6 mg Cu-glycine chelate in the total group and in women but did not change in men. Caeruloplasmin oxidase activity was significantly higher (P < 0.05), in men after supplementation with 3 mg Cu-glycine chelate, while caeruloplasmin protein concentration was significantly lower in men after supplementation with 6 mg Cu-glycine chelate (P < 0.05). Serum diamine oxidase activity was significantly higher after all supplementation regimens in the total group and in both men and women (P < 0.01). These results indicate that serum diamine oxidase activity is sensitive to changes in dietary Cu intakes and may also have the potential to evaluate changes in Cu status in healthy adult human subjects.

Nonalcoholic red wine extract and quercetin inhibit LDL oxidation without affecting plasma antioxidant vitamin and carotenoid concentrations

BACKGROUND

Antioxidant enrichment of LDL can increase its resistance to oxidation and hence reduce its atherogenicity. The objective of the present study was to investigate whether in vivo supplementation with nonalcoholic red wine extract and quercetin can increase the oxidative resistance of LDL, and also whether the supplementation has any effect on other antioxidative micronutrients present in the blood.

METHODS

Twenty-one male subjects were supplemented with a placebo drink for 2 weeks and randomized into two groups. One group (n = 11) received the red wine extract (1 g/day, equivalent to 375 mL of red wine) and the other group (n = 10) quercetin (30 mg/day) for 2 weeks, followed by a 5-week washout period.

RESULTS

In the red wine extract-supplemented group, ex vivo copper-initiated oxidation of LDL (lag phase, mean +/- SD) was 40 +/- 11 min at the baseline, and increased significantly to 47 +/- 6 min [P <0.05 compared with placebo (38 +/- 4 min) and the washout values (40 +/- 5 min)]. In the quercetin-supplemented group, the lag phase was 44 +/- 11 and 40 +/- 5 min for the baseline and placebo, respectively, and increased significantly to 51 +/- 7 min [P <0.05 compared with placebo and washout (41 +/- 9 min)] after supplementation. Plasma lipids (triglycerides, total cholesterol, LDL- and HDL-cholesterol) did not change during the study period. Supplementation with red wine extract or quercetin had no effect on plasma vitamin C and E, retinol, and carotenoid concentrations.

CONCLUSIONS

Alcohol-free red wine extract and one of its components, quercetin, can inhibit LDL oxidation after in vivo supplementation; such "inhibition" is unrelated to changes in antioxidant vitamin and carotenoid concentrations.

Trust and transforming medical institutions

Medicine needs our trust. We need to be able to rely on individual clinicians and researchers, and we need to be able to have confidence in hospitals and clinics. Yet the organization of our healthcare institutions is not designed to promote that trust. In fact, the structure of our medical institutions seems to undermine our faith.

The effect of copper supplementation on red blood cell oxidizability and plasma antioxidants in middle-aged healthy volunteers

A multicenter European study (FoodCue) was undertaken to provide data on the significance of increased dietary copper as a pro-oxidant or antioxidant in vivo. The present work describes the effect of Cu supplementation on (2,2'-azo-bis(2-amidinopropane) hydrochloride (AAPH)-induced red blood cell oxidation in middle-aged people. Double-blinded copper supplementation was achieved in 26 healthy volunteers (50-70 years) with pills containing 3 mg CuSO(4), 3 mg Cu glycine chelate (CuG) and 6 mg CuG. Each 6 week supplementation period was preceded and followed by 6 weeks of washout (WO) on placebo. The results show significant increases in time necessary to achieve 50% hemolysis (LT(50)) after 3CuSO(4) and 6CuG compared with values after WO periods. Cu supplementation did not increase the levels of (Cu,Zn)SOD activity in red blood cells. Resistance to hemolysis was significantly and positively correlated (r =.30, p <.01) with alpha- and beta-carotene content in the plasma. Together, these data suggest that intake of copper as high as 7 mg/d has no pro-oxidant activity and may rather result in protection of red blood cells against oxidation. The decreased oxidizability of red blood cells did not result from increased (Cu,Zn)SOD activity and may occur through other mechanisms such as changes in membrane antioxidant content.

Assessing Age-Related Changes in Antioxidant Status : The FRASC Assay for Total Antioxidant Power and Ascorbic Acid Concentration in Biological Fluids

There is accumulating evidence that oxidative damage to protein, lipid, carbohydrate and DNA is an important cause and/or effect of cellular and subcellular changes associated with disease, and is responsible for at least some of the physiological, but ultimately fatal, changes that accompany aging (1-8). Advancing age brings increasing risk of chronic degenerative disease including cancer, cardiovascular disease, cataracts, and dementia (1-6, 8).Immune status declines, with consequent increased risk of infection and, owing to a combination of physical and socioeconomic factors, nutritional status is often poor in the elderly, increasing the likelihood of poor antioxidant status (9).

Marginal copper deficiency and atherosclerosis

Copper is an essential trace element in the maintenance of the cardiovascular system. Copper-deficient diets can elicit, in animals, structural and functional changes that are comparable to those observed in coronary heart disease. In this study, the effect of dietary-induced copper deficiency on aortic lesion development was measured by quantitative image analysis in C57BL/6 mice that are susceptible to diet-induced aortic lesions. The diets administered were severely copper deficient (0.2 mg/kg diet), marginally deficient (0.6 mg/kg diet), or copper adequate (6.0 mg/kg diet). Similarly, increased aortic lesion areas and elevated serum cholesterol were demonstrated in both deficient groups, compared with the copper-adequate group. Evidence for graded differences in copper status among the dietary groups was shown by the dose-response increase in liver copper concentration, copper-zinc superoxide dismutase and cytochrome-c oxidase activities, together with serum caeruloplasmin oxidase with increasing intakes of dietary copper. Despite the difference in copper status between the copper marginal and severely deficient groups, similar lesions found in both groups of mice suggest a threshold effect of copper deficiency on lesion formation.

Plasma diamine oxidase activity is greater in copper-adequate than copper-marginal or copper-deficient rats

The object of this study was to determine whether serum diamine oxidase activity could distinguish among adequate, marginal and deficient copper status in rats. Male weanling Sprague-Dawley rats (n = 21) were randomly assigned to one of three dietary regimens, with copper concentrations of 0.52, 1.73 and 6.7 mg/kg diet. On completion of the study, body weights were significantly different among dietary groups, with copper-marginal rats displaying the highest mean weight and copper-deficient rats the lowest. Copper-deficient rats ate significantly less food than the other two groups. Rats fed the three diets had significantly different liver copper concentrations. Liver and heart superoxide dismutase and cytochrome c oxidase activities, and plasma ceruloplasmin and erythrocyte superoxide dismutase activities were significantly lower in the copper-deficient rats than in the other two groups. Plasma diamine oxidase activity was lower in both copper-deficient (0.18 +/- 0.11 U/L) and marginal (0.21 +/- 0.11 U/L) rats compared with copper-adequate rats (3.35 +/- 0.28 U/L). Of the biochemical indices measured, only liver copper concentration (-20%) and plasma diamine oxidase activity (-94%) differed between rats fed copper-marginal and copper-adequate diets. Plasma diamine oxidase activity, therefore, may be a sensitive functional biomarker of suboptimal copper status.

Dietary antioxidant supplementation and DNA damage in smokers and nonsmokers

Deficiencies of antioxidant nutrients have been implicated in the etiology of lung and other cancers. However, most intervention trials with antioxidant nutrients have not shown beneficial effects, and some have indicated that beta-carotene may be deleterious. This randomized, double-blind, placebo-controlled study evaluated the effects of five short-term (4-wk) antioxidant nutrient supplement regimens [ascorbic acid (350 mg), RRR-alpha-tocopherol (250 mg), beta-carotene (60 mg), selenium (80 micrograms as sodium selenite), ascorbic acid (350 mg) + RRR-alpha-tocopherol (250 mg)] on plasma antioxidants and mononuclear leukocyte DNA damage in male smokers (n = 9) and nonsmokers (n = 12). Plasma concentrations of ascorbic acid and tocopherol were significantly increased by supplementation, but there was no significant change in plasma beta-carotene or blood glutathione peroxidase activity after supplementation with beta-carotene or selenium. DNA damage in mononuclear leukocytes, as assessed by comet assay, was not affected by any supplementation regimen. DNA damage, as assessed by 8-hydroxydeoxyguanosine in mononuclear leukocytes, was not influenced by ascorbic acid, alpha-tocopherol, or selenium supplementation in smokers or nonsmokers, but beta-carotene supplementation resulted in significant differences between smokers and nonsmokers in the level of oxidative DNA damage, with decreases in smokers and increases in smokers. This is a further indication of the differential effects of supplemental beta-carotene in smokers and nonsmokers.

Further evolution of a literature database: the international use of a common software structure and methodology for the establishment of national consultation/liaison databases

Every day there are 6000-7000 papers published in science. Since the C-L psychiatrist may be asked to consult on a patient with any medical illness, and who may be on any medical drug, methods need to be developed to review the recent literature and have an awareness of current findings. At the same time, teachers need to develop a current listing of seminal papers for trainees and practitioners of this subspecialty of psychiatry. Experts chosen because of their writings and acknowledged contributions to their subspecialty interests have sifted through thousands of articles to select the ones they regard as the most important for trainees in C-L psychiatry. In addition, certain countries--Spain, Portugal, Germany, Mexico, Australia and Brazil are developing national databases of C-L literature not only for their own use, but also to bring them to the attention of other parts of the world. This fifth iteration of the C-L literature database has especially targeted the period of 1996-1999--the millennium issue--in order to have easier access to contemporary essential studies on common problems. Part II of this issue describes the seminal cardiac drug-psychotropic drug interactions that the C-L psychiatrist may encounter in the most common medical disease in the United States--coronary heart disease--with advise to the practitioner as to their management. The use of the Internet and institutional Intranets is described.

Cardiac drug and psychotropic drug interactions: significance and recommendations

Understanding cardiac drug interactions with concurrent psychotropic prescriptions is essential for the practicing cardiologist and primary care physician, as well as for the psychiatrist. There has been an explosive use of new drugs in both psychiatry and cardiology without widespread knowledge of their potential interactions. The increasing tendency toward poly-pharmacy, the use of psychotropic medications by cardiologists and primary care physicians caring for cardiac patients, and the growth of the aging population present major challenges for the practitioner. Finally, there is a need to have models/paradigms for predicting potential drug interactions--e.g., the Cytochrome p450 schema. This paper describes a method to identify, understand, and codify the interactions between psychotropic and cardiac drugs, a systematic approach for updating this key database and specific cardiac-psychotropic drug interactions. Specifically, this paper 1) details the interactions, 2) addresses the level of their clinical significance, 3) describes the potential mechanism(s) of the interactions, and 4) offers recommendations to the clinician. Since the majority of the original clinical trials, either for cardiac medications or psychotropic drugs, do not include studies comparing these two drug domains contemporaneously, their interactions often become known only with their combined use in the clinical arena, using the patient as "guinea pig," and through subsequent reporting.

No effect of copper supplementation on biochemical markers of bone metabolism in healthy adults

The influence of Cu supplementation of the usual diet for 6 weeks on biochemical markers of bone turnover and on putative indices of Cu status was investigated in healthy adults (twelve male and twelve female) aged 22-46 years, who participated in a double-blind placebo-controlled repeated crossover study. The study consisted of three 6-week supplementation regimens of 3 mg CuSO4, 3 mg Cu-glycine chelate (CuGC), and 6 mg CuGC, each separated by placebo periods of equal length. During baseline and on the last day of each dietary period, fasting morning first-void urine and fasting blood serum, plasma and erythrocytes were collected. The habitual dietary Cu intakes in males and females were approximately 1.4 and 1.1 mg/d respectively. Females had significantly higher (50%) plasma caeruloplasmin (Cp) protein concentrations than males at baseline. Cu supplementation had no effect on erythrocyte superoxide dismutase (SOD, EC 1.15.1.1) activity or plasma Cp protein (putative indices of Cu status) in the total group. Similarly, serum osteocalcin (a marker of bone formation), urinary creatinine (Cr) concentration, urinary pyridinoline: Cr or deoxypyridinoline: Cr excretion (markers of bone resorption) were unaffected in either the total group or in males and females separately, by any Cu supplementation regimen. It is concluded that Cu supplementation of the usual diet in healthy adult males and females had no effect on biochemical markers of bone formation or bone resorption over 6-week periods.

Antioxidant enzymes, inflammatory indices and lifestyle factors in older men: a cohort analysis

We examined the relationship between blood antioxidant enzyme activities, indices of inflammatory status and a number of lifestyle factors in the Caerphilly prospective cohort study of ischaemic heart disease. The study began in 1979 and is based on a representative male population sample. Initially 2512 men were seen in phase I, and followed-up every 5 years in phases II and III; they have recently been seen in phase IV. Data on social class, smoking habit, alcohol consumption were obtained by questionnaire, and body mass index was measured. Antioxidant enzyme activities and indices of inflammatory status were estimated by standard techniques. Significant associations were observed for: age with alpha-1-antichymotrypsin (p < 0.0001) and with caeruloplasmin, both protein and oxidase (p < 0.0001); smoking habit with alpha-1-antichymotrypsin (p < 0.0001), with caeruloplasmin, both protein and oxidase (p < 0.0001) and with glutathione peroxidose (GPX) (p < 0.0001); social class with alpha-1-antichymotrypsin (p < 0.0001), with caeruloplasmin both protein (p < 0.001) and oxidase (p < 0.01) and with GPX (p < 0.0001); body mass index with alpha-1-antichymotrypsin (p < 0.0001) and with caeruloplasmin protein (p < 0.001). There was no significant association between alcohol consumption and any of the blood enzymes measured. Factor analysis produced a three-factor model (explaining 65.9% of the variation in the data set) which appeared to indicate close inter-relationships among antioxidants.

Oxidative stress and iron are implicated in fragmenting vacuoles of Saccharomyces cerevisiae lacking Cu,Zn-superoxide dismutase

The absence of the antioxidant enzyme Cu,Zn-superoxide dismutase (SOD1) is shown here to cause vacuolar fragmentation in Saccharomyces cerevisiae. Wild-type yeast have 1-3 large vacuoles whereas the sod1Delta yeast have as many as 50 smaller vacuoles. Evidence that this fragmentation is oxygen-mediated includes the findings that aerobically (but not anaerobically) grown sod1Delta yeast exhibit aberrant vacuoles and genetic suppressors of other oxygen-dependent sod1 null phenotypes rescue the vacuole defect. Surprisingly, iron also is implicated in the fragmentation process as iron addition exacerbates the sod1Delta vacuole defect while iron starvation ameliorates it. Because the vacuole is reported to be a site of iron storage and iron reacts avidly with reactive oxygen species to generate toxic side products, we propose that vacuole damage in sod1Delta cells arises from an elevation of iron-mediated oxidation within the vacuole or from elevated pools of "free" iron that may bind nonproductively to vacuolar ligands. Furthermore, additional pleiotropic phenotypes of sod1Delta cells (including increased sensitivity to pH, nutrient deprivation, and metals) may be secondary to vacuolar compromise. Our findings support the hypothesis that oxidative stress alters cellular iron homeostasis which in turn increases oxidative damage. Thus, our findings may have medical relevance as both oxidative stress and alterations in iron homeostasis have been implicated in diverse human disease processes. Our findings suggest that strategies to decrease intracellular iron may significantly reduce oxidatively induced cellular damage.

Consumption of green tea causes rapid increase in plasma antioxidant power in humans

Green tea contains polyphenolic antioxidants that have shown anticarcinogenic properties in animal and in vitro experimental studies. Current data regarding absorption and bioavailability of tea antioxidants in humans, however, are conflicting. In this study, plasma and urine antioxidant power after ingestion of green tea was measured using the ferric reducing/antioxidant power (FRAP) assay (US patent pending) to assess absorption, systemic distribution, and renal excretion of green tea antioxidants in healthy adults. Results showed that absorption of green tea antioxidants was rapid, with peak increase in plasma FRAP of around 4% at 40 minutes after ingestion: mean increase was 44 +/- 9 (SE) mumol/l. Excretion of polyphenolic antioxidants was also fast, peaking at 60-90 minutes, with significant correlation between urinary FRAP values and urinary total phenolic concentrations (r = 0.845, p < 0.001). In control studies, no increase in plasma or urine FRAP values was seen after intake of water. Although the amount of antioxidants absorbed was relatively small and the increase in plasma antioxidant power was of short duration, results demonstrate that some potentially anticarcinogenic polyphenolic antioxidants in green tea enter the systemic circulation soon after ingestion and cause a significant increase in plasma antioxidant status. This increase may, in turn, lower oxidative damage to DNA and so decrease risk of cancer.

Determinants of p,p-dichlorodiphenyldichloroethane (DDE) concentration in adipose tissue in women from five European cities

To identify the determinants of p,p'-dichlorodiphenyldichloroethane (p,p'-DDE) in adipose tissue in subjects who participated in a cross-sectional study, we analyzed fatty acids, antioxidants, and p,p'-DDE in aspirates of adipose tissue of 328 postmenopausal women from 5 European countries. The overall mean of p,p'-DDE concentration was 1.66 microg/g of fatty acids (95% confidence interval = 1.46, 1.88). In a multiple-regression analysis, the main predictors of log10(p,p'DDE) were center of recruitment (p < .0001), adipose arachidic acid (p = .001), and adipose retinol (p = .04). These factors explained 14.9% of the overall variability of log10(p,p'-DDE). In our subjects, adipose tissue p,p'DDE concentrations were only weakly related with biomarkers reflecting intake of fish and other foods. This result is consistent with the notion that p,p'-DDE exists in different foods and, given the widespread contamination of the food chain, is relatively evenly distributed among foods.

Effect of cholesterol feeding on DNA damage in male and female Syrian hamsters

Cholesterol oxides are cytotoxic and have been implicated in many disease processes; however, it has been proposed that cholesterol oxides result from cholesterol acting as a sacrificial antioxidant. In this study, the effect of dietary cholesterol on DNA damage, assessed by the alkaline comet assay, was examined in male and female Syrian hamsters. Animals were fed ad libitum a modified AIN-76 diet (control) or a diet with 0.5% cholesterol for 10 weeks. Following the 10-week feeding period, there was no significant difference in body weight between cholesterol-fed and control animals. Cholesterol feeding resulted in significant liver hypertrophy, and increased plasma total and HDL cholesterol in both male and female animals compared with controls. There was no difference in liver cell DNA damage levels as measured by the comet assay. Heart cells from cholesterol-fed hamsters, however, showed a significant decrease in tail DNA (p = 0.050) indicating decreased damage compared with controls and a possible protective effect of cholesterol against DNA damage.

“antioxidant” (reducing) efficiency of ascorbate in plasma is not affected by concentration

Ascorbate (vitamin C), an important dietary derived antioxidant, reportedly shows decreasing "antioxidant efficiency" with increasing concentrations in indirect radical trapping methods of antioxidant capacity. This study investigated the effect of concentration on antioxidant efficiency of ascorbate using a direct test of antioxidant capacity, the ferric reducing/antioxidant power test (FRAP assay). Results showed that the antioxidant efficiency factor of ascorbate was 2 and was constant over a wide concentration range in both plasma and pure aqueous solution. However, the absolute amount of ascorbate lost per unit of time increased with concentration. Furthermore, ascorbate was less stable in plasma than in aqueous solutions of similar pH and less stable in ethylenediamine tetraacetic acid (EDTA) than in heparinized plasma. Results indicate that previously reported concentration-dependent changes in antioxidant efficiency of ascorbate may have been caused by loss of ascorbate prior to and during testing, and by methodologic characteristics of indirect peroxyl radical trapping tests of antioxidant capacity. Therefore, it is suggested that the premise that the antioxidant efficiency of ascorbate is concentration-dependent is largely methodologically derived and does not reflect the antioxidant behavior of ascorbate per se.

Fish oil supplementation with and without added vitamin E differentially modulates plasma antioxidant concentrations in healthy women

The purpose of this study was to assess the effect of fish oil with or without vitamin E on plasma vitamin antioxidants. Thirty-three apparently healthy women aged 18-28 yr were recruited from the university environs, and 30 completed the double-blinded, parallel design supplementation trial. Blood samples were collected at baseline (week 0) and following 28 d of supplementation with three capsules/d (0.8 g x 3) of either fish oil (FO) or FO with vitamin E (3 IU/g) (FOE). An additional blood sample was taken at day 91 (washout). Plasma antioxidant vitamins, fatty acid composition, and lipid peroxides were measured. Plasma alpha-tocopherol concentrations were increased significantly in both groups postsupplementation FO (P = 0.018) and FOE (P = 0.003) compared with baseline and washout values. Plasma retinol concentration was significantly increased (P = 0.034) compared with baseline and washout values following supplementation with FOE but not FO, while plasma beta-carotene was significantly increased (P = 0.036), compared with baseline and washout values, following supplementation with FO but not FOE. There was a trend (P = 0.059) toward decreased plasma ascorbic acid following FO supplementation compared with baseline and washout. Plasma lipid peroxides did not change following either supplementation. Results suggest that low-dose FO feeding with and without vitamin E differentially modulates plasma antioxidant vitamins but has no significant effect on lipid peroxidation.

Riboflavin and vitamin B-6 intakes and status and biochemical response to riboflavin supplementation in free-living elderly people

Free-living elderly people aged > or = 65 y were recruited to assess riboflavin and vitamin B-6 intakes and status and the effect of riboflavin supplementation on biochemical indicators of these 2 vitamins. The status of riboflavin (erythrocyte glutathione reductase activation coefficient; EGRAC) and vitamin B-6 (plasma pyridoxal-5'-phosphate; PLP) were determined in a total sample of 92 subjects, from whom dietary intake data were obtained by using the diet history method (n = 83). Although dietary intakes of both vitamins were considered to be adequate according to current reference values, abnormal EGRAC and plasma PLP values were identified in 49% and 38% of subjects, respectively, with 21% having suboptimal status for both nutrients. A subgroup of subjects from the initial sample (n = 45) was assigned in a double-blind manner to receive either 1.6 or 25 mg riboflavin or placebo daily for 12 wk. In those subjects with a baseline EGRAC or plasma PLP value falling outside the currently accepted threshold value for adequacy, low-dose riboflavin supplementation improved status of the limiting nutrient significantly (P<0.0001 and P = 0.020 for EGRAC and plasma PLP responses, respectively). We conclude that a high proportion of healthy elderly people may have suboptimal status for these nutrients despite apparently adequate dietary intakes. Furthermore, we showed that riboflavin supplementation at physiologic doses corrects biochemical abnormalities of not only EGRAC, but also plasma PLP, confirming the biochemical interdependency of these vitamins and suggesting that riboflavin is the limiting nutrient.

Tissue stores of individual monounsaturated fatty acids and breast cancer: the EURAMIC study. European Community Multicenter Study on Antioxidants, Myocardial Infarction, and Breast Cancer

The strongest evidence that monunsaturated fat may influence breast cancer risk comes from studies of southern European populations, in whom intake of oleic acid sources, particularly olive oil, appears protective. No previous study has examined the relation of adipose tissue fatty acid content to breast cancer in such a population. We used adipose biopsies with diverse fat intake patterns gathered in 5 European centers, including southern Europe (Malaga, Spain), to test the hypothesis that stores of oleic acid or other monounsaturates are inversely associated with breast cancer. Gluteal fat aspirates were obtained from 291 postmenopausal incident breast cancer patients and 351 control subjects, frequency-matched for age and catchment area. Logistic regression was used to model breast cancer by monounsaturates, with established risk factors controlled for. Oleic acid showed a strong inverse association with breast cancer in the Spanish center. The odds ratio for the difference between 75th and 25th percentiles was 0.40 (95% CI: 0.28, 0.58) in Malaga and 1.27 (0.88, 1.85) in all other centers pooled, with a peak at 2.36 (1.01, 5.50) for Zeist. Palmitoleic and myristoleic acids showed evidence of an inverse association outside Spain, and cis-vaccenic acid showed a positive association in 3 centers. These data do not support the hypothesis that increasing tissue stores of oleic acid are protective against breast cancer in non-Spanish populations. This finding implies that the strong protective associations reported for olive oil intake in dietary studies may be due to some other protective components of the oil and not to the direct effect of oleic acid uptake. Alternatively, high olive oil intake may indicate some other protective aspect of the lifestyle of these women.

Monocyte tissue factor-like activity in post myocardial infarction patients

It is widely recognized that thrombosis is the major event in the evolution of stable vascular disease to unstable ischaemic syndromes including myocardial infarction and stroke. The purpose of this case-control study was to establish clinical and laboratory data on the possible relationship between specific components of the haemostatic system and coronary heart disease. The procoagulant activity (PCA) of peripheral monocytes and polymorphonuclear neutrophils was assessed in 21 males who had suffered a myocardial infarction (MI) and in age-matched controls. In addition, total factor VII activity, fibrinogen, tissue factor pathway inhibitor (TFPI). D-dimers, tissue plasminogen activator (t-PA), plasminogen activator inhibitor (PAI-1), tumour necrosis factor-alpha (TNF-alpha) and full blood counts were measured. Post MI patients had significantly higher monocyte PCA, higher plasma concentrations of TFPI, fibrinogen, t-PA, T/P100 and also higher total white blood cell and neutrophil counts compared to age-matched controls. This elevated procoagulant state in post MI patients could further exacerbate the disease process and increase the risk of subsequent acute ischaemic events.

Using computer databases to predict and avoid drug-drug interactions in the cancer patient requiring psychotropics

Psychotropic drug interactions with medical prescriptions is an essential knowledge base for the practicing oncologist as well as the psychiatrist. This paper describes a method to identify, understand, and develop a conceptual framework to codify psychotropic-medical drug interactions; a systemic approach for updating this key database, and a software system to assist in the management of this ever unfolding sphere of knowledge; and, a set of instruments to provide ongoing developments in this important area. Since many of the trials either for oncological medications or psychotropic drugs did not include studies comparing these two domains, their interactions often only become known with their utilization and subsequent reporting.

Plasma ascorbate and vitamin E levels in Hong Kong Chinese

OBJECTIVE

To describe fasting plasma total- and lipid standardised-vitamin E and ascorbate concentrations in Hong Kong Chinese subjects, and to explore age-, diet- and sex-related differences.

DESIGN

Observational study.

SETTING

Hong Kong.

SUBJECTS

One hundred and fifty randomly selected Chinese subjects.

INTERVENTIONS

Fasting plasma concentrations of ascorbate, total vitamin E and lipid standardised vitamin E (Vit E(LS), expressed as micromol vitamin E/mmol total cholesterol plus triglycerides) were measured.

RESULTS

Total vitamin E concentrations ranged from 6-53 micromol/l (mean 24; s.d. 8.5), and Vit ELS from 0.85-7.09 micromol/mmol (mean 3.61; s.d. 1.19). Plasma Vit E(LS) concentrations in women were higher (P = 0.02) than in men: mean (median) concentrations 3.82 (3.88) and 3.37 (3.28) micromol/mmol, respectively. Vit ELS concentrations in men decreased with age. Mean (s.d.) plasma ascorbate concentrations in men and women were 49.7 (14.0) and 51.6 (21.6) micromol/l respectively, and did not show the significant age- and sex- differences reportedly found in Western studies.

CONCLUSIONS

The hypothesis that Hong Kong Chinese, with their low risk of CHD, might have high Vit E(LS) levels in fasting plasma is not supported by the results obtained. Moreover, results showed male female differences and, in men, a previously unreported age-related decrease in plasma Vit E(LS) concentration which cannot be accounted for by concomitant differences in dietary intake of vitamin E alone. Results also suggest that the age- and sex- differences in plasma ascorbate seen in Western populations can be avoided by increased vitamin C intake.