Supplementation with antioxidants and folinic acid for children with Down’s syndrome: randomised controlled trial

Objectives To assess whether supplementation with antioxidants, folinic acid, or both improves the psychomotor and language development of children with Down’s syndrome.Design Randomised controlled trial with two by two factorial design.Setting Children living in the Midlands, Greater London, and the south west of England.Participants 156 infants aged under 7 months with trisomy 21.Intervention Daily oral supplementation with antioxidants (selenium 10 μg, zinc 5 mg, vitamin A 0.9 mg, vitamin E 100 mg, and vitamin C 50 mg), folinic acid (0.1 mg), antioxidants and folinic acid combined, or placebo.Main outcome measures Griffiths developmental quotient and an adapted MacArthur communicative development inventory 18 months after starting supplementation; biochemical markers in blood and urine at age 12 months.Results Children randomised to antioxidant supplements attained similar developmental outcomes to those without antioxidants (mean Griffiths developmental quotient 57.3 v 56.1; adjusted mean difference 1.2 points, 95% confidence interval −2.2 to 4.6). Comparison of children randomised to folinic acid supplements or no folinic acid also showed no significant differences in Griffiths developmental quotient (mean 57.6 v 55.9; adjusted mean difference 1.7, −1.7 to 5.1). No between group differences were seen in the mean numbers of words said or signed: for antioxidants versus none the ratio of means was 0.85 (95% confidence interval 0.6 to 1.2), and for folinic acid versus none it was 1.24 (0.87 to 1.77). No significant differences were found between any of the groups in the biochemical outcomes measured. Adjustment for potential confounders did not appreciably change the results.Conclusions This study provides no evidence to support the use of antioxidant or folinic acid supplements in children with Down’s syndrome.Trial registration Clinical trials {"type":"clinical-trial","attrs":{"text":"NCT00378456","term_id":"NCT00378456"}}NCT00378456.     

Clinical trials of antioxidants as cancer prevention agents: past, present, and future

The purpose of this review is to summarize the most important human clinical trials of antioxidants as cancer prevention agents conducted to date, provide an overview of currently ongoing studies, and discuss future steps needed to advance research in this field. To date there have been several large (at least 7000 participants) trials testing the efficacy of antioxidant supplements in preventing cancer. The specific agents (diet-derived direct antioxidants and essential components of antioxidant enzymes) tested in those trials included β-carotene, vitamin E, vitamin C, selenium, retinol, zinc, riboflavin, and molybdenum. None of the completed trials produced convincing evidence to justify the use of traditional antioxidant-related vitamins or minerals for cancer prevention. Our search of ongoing trials identified six projects at various stages of completion. Five of those six trials use selenium as the intervention of interest delivered either alone or in combination with other agents. The lack of success to date can be explained by a variety of factors that need to be considered in the next generation research. These factors include lack of good biological rationale for selecting specific agents of interest; limited number of agents tested to date; use of pharmacological, rather than dietary, doses; and insufficient duration of intervention and follow-up. The latter consideration underscores the need for alternative endpoints that are associated with increased risk of neoplasia (i.e., biomarkers of risk), but are detectable prior to tumor occurrence. Although dietary antioxidants are a large and diverse group of compounds, only a small proportion of candidate agents have been tested. In summary, the strategy of focusing on large high-budget studies using cancer incidence as the endpoint and testing a relatively limited number of antioxidant agents has been largely unsuccessful. This lack of success in previous trials should not preclude us from seeking novel ways of preventing cancer by modulating oxidative balance. On the contrary, the well demonstrated mechanistic link between excessive oxidative stress and carcinogenesis underscores the need for new studies. It appears that future large-scale projects should be preceded by smaller, shorter, less expensive biomarker-based studies that can serve as a link from mechanistic and observational research to human cancer prevention trials. These relatively inexpensive studies would provide human experimental evidence for the likely efficacy, optimum dose, and long-term safety of the intervention of interest that would then guide the design of safe, more definitive large-scale trials.     

Antioxidants and vision health: facts and fiction

A number of nutritional supplements containing antioxidants are advertised for better vision health. Do they benefit the average consumer? The literature was examined for the effectiveness of antioxidants for human eye health, and for the intricacies in collection of such evidence. The following diseases were considered: cataract, glaucoma, age-related macular degeneration (AMD), retinopathy, retinitis pigmentosa, eye infections, and uveitis. The literature indicates that antioxidant supplements plus lutein have a reasonable probability of retarding AMD. For glaucoma, such supplements were ineffectual in some studies but useful in others. In some studies, antioxidant rich fruits and vegetables were also useful for protection against glaucoma. For diabetic retinopathy, antioxidant supplements may have a small benefit, if any, but only as an adjunct to glycemic control. In very high-risk premature retinopathy and retinitis pigmentosa, antioxidant supplements may be beneficial but those with excess Vitamin E should be avoided. For cataract, there is no evidence for an advantage of such nutritional supplements. However, lubricant drops containing N-acetylcarnosine may be helpful in initial stages of the disease. For eye infections and other causes of uveitis, antioxidants have not been found useful. We recommend that a diet high in antioxidant rich foods should be developed as a habit from an early age. However, when initial signs of vision health deterioration are observed, the appropriate nutritional supplement products may be recommended but only to augment the primary medical treatments.     

Lowering blood homocysteine with folic acid based supplements: meta-analysis of randomised trials

Objective: To determine the size of reduction in homocysteine concentrations produced by dietary supplementation with folic acid and with vitamins B-12 or B-6. Design: Meta-analysis of randomised controlled trials that assessed the effects of folic acid based supplements on blood homocysteine concentrations. Multivariate regression analysis was used to determine the effects on homocysteine concentrations of different doses of folic acid and of the addition of vitamin B-12 or B-6. Subjects: Individual data on 1114 people included in 12 trials. Findings: The proportional and absolute reductions in blood homocysteine produced by folic acid supplements were greater at higher pretreatment blood homocysteine concentrations (P<0.001) and at lower pretreatment blood folate concentrations (P<0.001). After standardisation to pretreatment blood concentrations of homocysteine of 12 μmol/l and of folate of 12 nmol/l (approximate average concentrations for Western populations), dietary folic acid reduced blood homocysteine concentrations by 25% (95% confidence interval 23% to 28%; P<0.001), with similar effects in the range of 0.5-5 mg folic acid daily. Vitamin B-12 (mean 0.5 mg daily) produced an additional 7% (3% to 10%) reduction in blood homocysteine. Vitamin B-6 (mean 16.5 mg daily) did not have a significant additional effect. Conclusions: Typically in Western populations, daily supplementation with both 0.5-5 mg folic acid and about 0.5 mg vitamin B-12 would be expected to reduce blood homocysteine concentrations by about a quarter to a third (for example, from about 12 μmol/l to 8-9 μmol/l). Large scale randomised trials of such regimens in high risk populations are now needed to determine whether lowering blood homocysteine concentrations reduces the risk of vascular disease.

Key messages

• Higher blood homocysteine concentrations seem to be associated with higher risks of occlusive vascular disease and with lower blood concentrations of folate and vitamins B-12 and B-6
• Proportional and absolute reductions in blood homocysteine concentrations with folic acid supplements are greater at higher pretreatment blood homocysteine concentrations and at lower pretreatment blood folate concentrations
• In typical Western populations, supplementation with both 0.5-5 mg daily folic acid and about 0.5 mg daily vitamin B-12 should reduce blood homocysteine concentrations by about a quarter to a third
• Large scale randomised trials of such regimens in people at high risk are now needed to determine whether lowering blood homocysteine concentrations reduces the risk of vascular disease

     

Oxidative stress and antioxidant deficiencies in asthma: potential modification by diet

The lungs of asthmatic patients are exposed to oxidative stress due to the generation of reactive oxygen and nitrogen species as a consequence of chronic airway inflammation. Increased concentrations of NO*, H2O2 and 8-isoprostane have been measured in exhaled breath and induced sputum of asthmatic patients. O2*-, NO*, and halides interact to form highly reactive species such as peroxynitrite and HOBr, which in turn cause nitration and bromination of protein tyrosine residues. Oxidative stress may also reduce glutathione levels and cause inactivation of antioxidant enzymes such as superoxide dismutase, with a consequent increase in apoptosis, shedding of airway epithelial cells and airway remodelling. The oxidant/antioxidant equilibrium in asthmatic patients may be further perturbed by low dietary intakes of the antioxidant vitamins C and E, selenium and flavonoids, with a consequent lowering of the concentrations of these and other non-dietary antioxidants such as bilirubin and albumin in plasma and airway epithelial lining fluid. Although supplementation with vitamins C and E appears to offer protection against the adverse effects of ozone, recent randomised, placebo-controlled trials of vitamin C or E supplements for patients with mild asthma have not shown significant benefits over standard therapy. However, genetic variation in glutathione S-transferase may influence the susceptibility of asthmatic individuals to oxidative stress and the extent to which they are likely to benefit from antioxidant supplementation. Long-term prospective trials are required to determine whether modification of dietary intake will benefit asthma patients and reduce the socio-economic burden of asthma in the community.     

Low density lipoprotein (LDL), atherosclerosis and antioxidants

A crucial and causative role in the pathogenesis of atherosclerosis is believed to be the oxidative modification of low density lipoprotein (LDL). The oxidation of LDL involves released free radical driven lipid peroxidation. Several lines of evidence support the role of oxidized LDL in atherogenesis. Epidemiologic studies have demonstrated an association between an increased intake of dietary antioxidant vitamins, such as vitamin E and vitamin C and reduced morbidity and mortality from coronary artery diseases. It is thus hypothesized that dietary antioxidants may help prevent the development and progression of atherosclerosis. The oxidation of LDL has been shown to be reduced by antioxidants, and, in animal models, improved antioxidants may offer possibilities for the prevention of atherosclerosis. The results of several on going long randomized intervention trials will provide valuahle information on the efficacy and safety of improved antioxidants in the prevention of atherosclerosis. This review a evaluates current literature involving antioxidants and vascular disease, with a particular focus on the potential mechanisms.     

Oxidative stress and antioxidant deficiencies in asthma: potential modification by diet

Abstract

The lungs of asthmatic patients are exposed to oxidative stress due to the generation of reactive oxygen and nitrogen species as a consequence of chronic airway inflammation. Increased concentrations of NO^?, H₂O₂ and 8-isoprostane have been measured in exhaled breath and induced sputum of asthmatic patients. O₂^??, NO^?, and halides interact to form highly reactive species such as peroxynitrite and HOBr, which in turn cause nitration and bromination of protein tyrosine residues. Oxidative stress may also reduce glutathione levels and cause inactivation of antioxidant enzymes such as superoxide dismutase, with a consequent increase in apoptosis, shedding of airway epithelial cells and airway remodelling. The oxidant/antioxidant equilibrium in asthmatic patients may be further perturbed by low dietary intakes of the antioxidant vitamins C and E, selenium and flavonoids, with a consequent lowering of the concentrations of these and other non-dietary antioxidants such as bilirubin and albumin in plasma and airway epithelial lining fluid. Although supplementation with vitamins C and E appears to offer protection against the adverse effects of ozone, recent randomised, placebo-controlled trials of vitamin C or E supplements for patients with mild asthma have not shown significant benefits over standard therapy. However, genetic variation in glutathione S-transferase may influence the susceptibility of asthmatic individuals to oxidative stress and the extent to which they are likely to benefit from antioxidant supplementation. Long-term prospective trials are required to determine whether modification of dietary intake will benefit asthma patients and reduce the socio-economic burden of asthma in the community.     

Dietary Total Antioxidant Capacity and Colorectal Cancer in the Italian EPIC Cohort

Background

Colorectal cancer is the third most common cancer worldwide. Diet has been hypothesized as involved in colorectal cancer etiology, but few studies on the influence of total dietary antioxidant intake on colorectal cancer risk have been performed.

Methods

We investigated the association between colorectal cancer risk and the total antioxidant capacity (TAC) of the diet, and also of intake of selected antioxidants, in 45,194 persons enrolled in 5 centers (Florence, Naples, Ragusa, Turin and Varese) of the European Prospective Investigation into Cancer and Nutrition (EPIC) Italy study. TAC was estimated by the Trolox equivalent antioxidant capacity (TEAC) assay. Hazard ratios (HRs) for developing colorectal cancer, and colon and rectal cancers separately, adjusted for confounders, were estimated for tertiles of TAC by Cox modeling, stratifying by center.

Results

Four hundred thirty-six colorectal cancers were diagnosed over a mean follow-up of 11.28 years. No significant association between dietary TAC and colorectal cancer incidence was found. However for the highest category of TAC compared to the lowest, risk of developing colon cancer was lower (HR: 0.63; 95% CI: 0.44–0.89, P trend: 0.008). By contrast, increasing TAC intake was associated with significantly increasing risks of rectal cancer (2nd tertile HR: 2.09; 95%CI: 1.19–3.66; 3rd tertile 2.48 95%CI: 1.32–4.66; P trend 0.007). Intakes of vitamin C, vitamin E, and ß-carotene were not significantly associated with colorectal cancer risk.

Conclusions

Further prospective studies are needed to confirm the contrasting effects of high total antioxidant intake on risk of colon and rectal cancers.     

Dietary intake of antioxidant supplements modulate antioxidant status and heat shock protein 70 synthesis

The physiological effects and efficacy of dietary intake of antioxidant supplements in humans remains controversial. Experiments involving dietary, often high, intake of a single antioxidant or vitamin may be seriously flawed given the interactive nature of antioxidants in vivo. The present studies were conducted on individuals (35-60 years of age) taking a commercial antioxidant mixture in a double-blind, placebo-controlled, cross-over study. Intake was two capsules per day, for 4 weeks, with a 4-week washout period in between active dose or placebo. Intake of antioxidants was associated with little change in superoxide dismutase activity, but an increase in glutathione peroxidase was noted. Haemolysis of red blood cells (erythrocytes) induced by the free radical generator AAPH was significantly reduced in individuals on antioxidant supplements. In lymphocytes isolated from individuals taking supplements, there was a marked increase, as compared with individuals on placebo, in the synthesis of heat shock protein 70 (hsp70) following heat shock from 37 degrees C to 42.5 degrees C. We conclude that dietary intake of a mixed antioxidant supplement leads to modulation of cellular redox status resulting in decreased oxidative stress and increased ability of lymphocytes to mount a stress response.     

Deleterious consequences of antioxidant supplementation on lifespan in a wild-derived mammal

While oxidative damage owing to reactive oxygen species (ROS) often increases with advancing age and is associated with many age-related diseases, its causative role in ageing is controversial. In particular, studies that have attempted to modulate ROS-induced damage, either upwards or downwards, using antioxidant or genetic approaches, generally do not show a predictable effect on lifespan. Here, we investigated whether dietary supplementation with either vitamin E (α-tocopherol) or vitamin C (ascorbic acid) affected oxidative damage and lifespan in short-tailed field voles, Microtus agrestis. We predicted that antioxidant supplementation would reduce ROS-induced oxidative damage and increase lifespan relative to unsupplemented controls. Antioxidant supplementation for nine months reduced hepatic lipid peroxidation, but DNA oxidative damage to hepatocytes and lymphocytes was unaffected. Surprisingly, antioxidant supplementation significantly shortened lifespan in voles maintained under both cold (7 ± 2°C) and warm (22 ± 2°C) conditions. These data further question the predictions of free-radical theory of ageing and critically, given our previous research in mice, indicate that similar levels of antioxidants can induce widely different interspecific effects on lifespan.     

Suboptimal Serum α-Tocopherol Concentrations Observed among Younger Adults and Those Depending Exclusively upon Food Sources,NHANES 2003-20061-3

Vitamin E is an essential nutrient for human health, with an established function as a lipid-soluble antioxidant that protects cell membranes from free radical damage. Low vitamin E status has been linked to multiple health outcomes, including total mortality. With vitamin E being identified as a ‘shortfall nutrient’ because >90% of American adults are not consuming recommended amounts of vitamin E, we aimed to determine the prevalence of both clinical vitamin E deficiency (serum α-tocopherol concentration < 12 μmol/L) and failure to meet a criterion of vitamin E adequacy, serum α-tocopherol concentration of 30 μmol/L, based on the Estimated Average Requirement (EAR) and lowest mortality rate in the Alpha-Tocopherol Beta-Carotene (ATBC) study. The most recent nationally-representative cross-sectional data (2003–2006) among non-institutionalized US citizens with available serum concentrations of α-tocopherol from the National Health and Nutrition Examination Survey (NHANES); Centers for Disease Control and Prevention were analyzed. Serum α-tocopherol distributions were compared between those reporting consumption of food without supplement use (FOOD) and food and supplement use (FOOD+DS) by sex, age, and race/ethnicity. Only 1% of the US population is clinically deficient. FOOD consumers have lower average α-tocopherol levels (24.9± 0.2 μmol/L) than FOOD+DS users (33.7 ± 0.3 μmol/L), even when adjusted for total cholesterol. Using a criterion of adequacy of 30 μmol/L, 87% of persons 20-30y and 43% of those 51+y had inadequate vitamin E status (p<0.01). A significant greater prevalence of FOOD compared to FOOD+DS users did not meet the criterion of adequacy which was based on the EAR and low ATBC mortality rate consistently across age, sex, and race/ethnic groups. The prevalence of inadequate vitamin E levels is significantly higher among non-users of dietary supplements. With declining usage of vitamin E supplements, the population should be monitored for changes in vitamin E status and related health outcomes.     

Vitamin E supplementation and macular degeneration: randomised controlled trial

ObjectiveTo determine whether vitamin E supplementation influences the incidence or rate of progression of age related maculopathy (AMD).DesignProspective randomised placebo controlled clinical trial.SettingAn urban study centre in a residential area supervised by university research staff.Participants1193 healthy volunteers aged between 55 and 80 years; 73% completed the trial on full protocol.InterventionsVitamin E 500 IU or placebo daily for four years.ResultsThe incidence of early age related macular degeneration (early AMD 3) was 8.6% in those receiving vitamin E versus 8.1% in those on placebo (relative risk 1.05, 95% confidence interval 0.69 to 1.61). For late disease the incidence was 0.8% versus 0.6% (1.36, 0.67 to 2.77). Further analysis showed no consistent differences in secondary outcomes.ConclusionDaily supplement with vitamin E supplement does not prevent the development or progression of early or later stages of age related macular degeneration.

What is already known on this topic

Age related macular degeneration is the leading cause of loss of vision and blindness in elderly people; for people aged ⩾90 years, two out of every three will be affected and one in four will become blindCurrently, there are no methods of prevention or treatment in most cases, though a third of cases are due to cigarette smokingAntioxidant vitamins have been suggested as a possible prevention

What this study adds

Daily supplementation with 500 mg vitamin E for four years did not alter the incidence or progression of AMD     

Nutrient intake and cataract extraction in women: a prospective study.

OBJECTIVE--To examine prospectively the association between dietary intake of vitamins C and E, carotene, and riboflavin and cataract extraction in women. DESIGN--Prospective cohort study beginning in 1980 with eight years of follow up. SETTING--11 states of the United States. PARTICIPANTS--Female registered nurses who were 45 to 67 years of age. 50,828 women were included in 1980 and others were added as they became 45 years of age. MAIN OUTCOME MEASURE--Incidence of extraction of senile cataracts. RESULTS--493 cataracts were extracted during 470,302 person years of follow up. Intake of carotene and vitamin A was inversely associated with cataract: in multivariate analyses, women in the highest fifth of total vitamin A intake (excluding supplements) had a 39% lower risk of cataract relative to women in the lowest fifth (relative risk 0.61; 95% confidence interval 0.45 to 0.81). Neither riboflavin nor dietary vitamins E or C were associated with cataract in a multivariate analysis. Among specific food items spinach (rather than carrots, the greatest source of beta carotene) was most consistently associated with a lower relative risk. The risk of cataract was 45% lower among women who used vitamin C supplements for 10 or more years(relative risk 0.55 (0.32 to 0.96)), but no association was noted for multivitamin intake. CONCLUSION--Dietary carotenoids, although not necessarily beta carotene, and long term vitamin C supplementation may decrease the risk of cataracts severe enough to require extraction.     

Will the 'Good Fairies' Please Prove to us that Vitamin E Lessens Human Degenerative Disease?

Recent research about the role of free radical derivatives of oxygen and nitrogen in biological systems has highlighted the possibility that antioxidants, such as vitamin E, that prevent these processes in vitro may be capable of carrying out a similar function in living organisms in vivo. There is increasing evidence that free radical reactions are involved in the early stages, or sometimes later on, in the development of human diseases, and it is therefore of particular interest to inquire whether vitamin E and other antioxidants, which are found in the human diets, may be capable of lowering the incidence of these diseases. Put simply, the proposition is that by improving human diets by increasing the quantity in them of antioxidants, it might be possible to reduce the incidence of a number of degenerative diseases. Of particular significance to these considerations is the likely role of the primary fat-soluble dietary antioxidant vitamin E in the prevention of degenerative diseases such as arteriosclerosis, which is frequently the cause of consequent heart attacks or stroke, and prevention of certain forms of cancer, as well as several other diseases. Substantial evidence for this proposition now exists, and this review is an attempt to give a brief account of the present position. Two kinds of evidence exist; on the one hand there is very substantial basic science evidence which indicates an involvement of free radical events, and a preventive role for vitamin E, in the development of human disease processes. On the other hand, there is also a large body of human epidemiological evidence which suggests that incidence of these diseases is lowered in populations having a high level of antioxidants, such as vitamin E, in their diet, or who have taken steps to enhance their level of intake of the vitamin by taking dietary supplements. There is also some evidence which suggests that intervention with dietary supplements of vitamin E can result in a lowered risk of disease, in particular of cardiovascular disease, which is a major killer disease among the developed nations of the world. The intense interest in this subject recently has as its objective the possibility that, by making some simple alterations to dietary lifestyle, or by enhancing the intake of vitamin E by fortification of foods, or by dietary supplements, it may be possible to reduce substantially the risk of a large amount of common, highly disabling human disease. By this simple means, therefore it may be possible to improve substantially the quality of human life, in particular for people of advancing years.     

Vitamin D supplementation worsens Alzheimer's progression: Animal model and human cohort studies

Vitamin D deficiency has been epidemiologically linked to Alzheimer''s disease (AD) and other dementias, but no interventional studies have proved causality. Our previous work revealed that the genomic vitamin D receptor (VDR) is already converted into a non‐genomic signaling pathway by forming a complex with p53 in the AD brain. Here, we extend our previous work to assess whether it is beneficial to supplement AD mice and humans with vitamin D. Intriguingly, we first observed that APP/PS1 mice fed a vitamin D‐sufficient diet showed significantly lower levels of serum vitamin D, suggesting its deficiency may be a consequence not a cause of AD. Moreover, supplementation of vitamin D led to increased Aβ deposition and exacerbated AD. Mechanistically, vitamin D supplementation did not rescue the genomic VDR/RXR complex but instead enhanced the non‐genomic VDR/p53 complex in AD brains. Consistently, our population‐based longitudinal study also showed that dementia‐free older adults (n = 14,648) taking vitamin D₃ supplements for over 146 days/year were 1.8 times more likely to develop dementia than those not taking the supplements. Among those with pre‐existing dementia (n = 980), those taking vitamin D₃ supplements for over 146 days/year had 2.17 times the risk of mortality than those not taking the supplements. Collectively, these animal model and human cohort studies caution against prolonged use of vitamin D by AD patients.     

Will the 'Good Fairies' Please Prove to us that Vitamin E Lessens Human Degenerative Disease?

Recent research about the role of free radical derivatives of oxygen and nitrogen in biological systems has highlighted the possibility that antioxidants, such as vitamin E, that prevent these processes in vitro may be capable of carrying out a similar function in living organisms in vivo. There is increasing evidence that free radical reactions are involved in the early stages, or sometimes later on, in the development of human diseases, and it is therefore of particular interest to inquire whether vitamin E and other antioxidants, which are found in the human diets, may be capable of lowering the incidence of these diseases. Put simply, the proposition is that by improving human diets by increasing the quantity in them of antioxidants, it might be possible to reduce the incidence of a number of degenerative diseases. Of particular significance to these considerations is the likely role of the primary fat-soluble dietary antioxidant vitamin E in the prevention of degenerative diseases such as arteriosclerosis, which is frequently the cause of consequent heart attacks or stroke, and prevention of certain forms of cancer, as well as several other diseases. Substantial evidence for this proposition now exists, and this review is an attempt to give a brief account of the present position. Two kinds of evidence exist; on the one hand there is very substantial basic science evidence which indicates an involvement of free radical events, and a preventive role for vitamin E, in the development of human disease processes. On the other hand, there is also a large body of human epidemiological evidence which suggests that incidence of these diseases is lowered in populations having a high level of antioxidants, such as vitamin E, in their diet, or who have taken steps to enhance their level of intake of the vitamin by taking dietary supplements. There is also some evidence which suggests that intervention with dietary supplements of vitamin E can result in a lowered risk of disease, in particular of cardiovascular disease, which is a major killer disease among the developed nations of the world. The intense interest in this subject recently has as its objective the possibility that, by making some simple alterations to dietary lifestyle, or by enhancing the intake of vitamin E by fortification of foods, or by dietary supplements, it may be possible to reduce substantially the risk of a large amount of common, highly disabling human disease. By this simple means, therefore it may be possible to improve substantially the quality of human life, in particular for people of advancing years.     

Dietary essential oils improve feed efficiency and hepatic antioxidant content of broiler chickens

The aim of this study was to test the hypothesis of an improved growth, dietary nutrient availability and overall health of broiler chickens reared on recycled litter when fed a standardised combination of essential oils (EO; carvacrol, cinnamaldehyde and capsicum oleoresin). To assess the effect of dietary treatments, feed intake, weight gain, feed efficiency, availability of dietary nutrients and energy, villus morphometry, excreta sialic acid concentration, hepatic antioxidants and serum amyloid A (SAA) when fed to broiler chickens were evaluated. Counts of Eimeria spp. oocysts were also determined in excreta samples. Four experimental diets were offered, including two basal control diets based on either wheat or maize that contained 215 g CP/kg and 12.13 MJ/kg metabolisable energy and another two diets using the basal control diets supplemented with the EO combination at 100 mg/kg diet. Each diet was fed to eight floor pens, containing two birds each, following randomisation. Birds fed the EO-supplemented diets had an improved (P<0.05) feed conversion ratio (FCR). Birds fed maize-based diet had an improved daily weight gain and FCR (P<0.05) compared with wheat-fed birds. Wheat-based diet tended (P=0.056) to have greater N-corrected apparent metabolisable energy and had greater fat retention coefficient (P<0.05) compared with maize-based diets. No differences (P>0.05) were observed in villus morphometry, sialic acid secretion, number of oocysts and SAA. Feeding the EO improved (P<0.05) the retention of dietary Ca and Na. Compared with maize, feeding wheat-based diets improved the retention coefficients for Ca, P and Na (P<0.05). Feeding dietary EO improved (P<0.05) the concentrations of the hepatic antioxidants, including carotene, coenzyme Q₁₀ and total vitamin E. The hepatic concentration of carotene of the maize-fed birds was 55.6% greater (P<0.05) compared with the wheat-fed birds. These results demonstrated that the addition of a standardised combination of EO in wheat- and maize-based diets provided benefits in terms of feed efficiency, mineral retention and antioxidant status of the birds when reared on recycled litter.     

Double blind, cluster randomised trial of low dose supplementation with vitamin A or beta carotene on mortality related to pregnancy in Nepal. The NNIPS-2 Study Group

ObjectiveTo assess the impact on mortality related to pregnancy of supplementing women of reproductive age each week with a recommended dietary allowance of vitamin A, either preformed or as β carotene.DesignDouble blind, cluster randomised, placebo controlled field trial.SettingRural southeast central plains of Nepal (Sarlahi district).Subjects44 646 married women, of whom 20 119 became pregnant 22 189 times.Intervention270 wards randomised to 3 groups of 90 each for women to receive weekly a single oral supplement of placebo, vitamin A (7000 μg retinol equivalents) or β carotene (42 mg, or 7000 μg retinol equivalents) for over 3½ years.ResultsMortality related to pregnancy in the placebo, vitamin A, and β carotene groups was 704, 426, and 361 deaths per 100 000 pregnancies, yielding relative risks (95% confidence intervals) of 0.60 (0.37 to 0.97) and 0.51 (0.30 to 0.86). This represented reductions of 40% (P<0.04) and 49% (P<0.01) among those who received vitamin A and β carotene. Combined, vitamin A or β carotene lowered mortality by 44% (0.56 (0.37 to 0.84), P<0.005) and reduced the maternal mortality ratio from 645 to 385 deaths per 100 000 live births, or by 40% (P<0.02). Differences in cause of death could not be reliably distinguished between supplemented and placebo groups.ConclusionSupplementation of women with either vitamin A or β carotene at recommended dietary amounts during childbearing years can lower mortality related to pregnancy in rural, undernourished populations of south Asia.

Key messages

• Maternal vitamin A deficiency, evident as night blindness or low serum retinol concentration during pregnancy, is widely prevalent in rural south Asia
• In Nepal, women of reproductive age who were given 7000 μg retinol equivalents of vitamin A on a weekly basis showed a reduction in mortality related to pregnancy of 40%
• Weekly dosing with 42 mg β carotene (also providing 7000 μg retinol equivalents) lowered their mortality by 49%
• Preventing maternal vitamin A deficiency in rural South Asia can lower the risk of mortality of women during and after pregnancy

     

Diabetes Mellitus and Risk of Age-Related Macular Degeneration: A Systematic Review and Meta-Analysis

Age-related macular degeneration (AMD) is a major cause of severe vision loss in elderly people. Diabetes mellitus is a common endocrine disorder with serious consequences, and diabetic retinopathy (DR) is the main ophthalmic complication. DR and AMD are different diseases and we seek to explore the relationship between diabetes and AMD. MEDLINE, EMBASE, and the Cochrane Library were searched for potentially eligible studies. Studies based on longitudinal cohort, cross-sectional, and case-control associations, reporting evaluation data of diabetes as an independent factor for AMD were included. Reports of relative risks (RRs), hazard ratios (HRs), odds ratio (ORs), or evaluation data of diabetes as an independent factor for AMD were included. Review Manager and STATA were used for the meta-analysis. Twenty four articles involving 27 study populations were included for meta-analysis. In 7 cohort studies, diabetes was shown to be a risk factor for AMD (OR, 1.05; 95% CI, 1.00–1.14). Results of 9 cross-sectional studies revealed consistent association of diabetes with AMD (OR, 1.21; 95% CI, 1.00–1.45), especially for late AMD (OR, 1.48; 95% CI, 1.44–1.51). Similar association was also detected for AMD (OR, 1.29; 95% CI, 1.13–1.49) and late AMD (OR, 1.16; 95% CI, 1.11–1.21) in 11 case-control studies. The pooled ORs for risk of neovascular AMD (nAMD) were 1.10 (95% CI, 0.96–1.26), 1.48 (95% CI, 1.44–1.51), and 1.15 (95% CI, 1.11–1.21) from cohort, cross-sectional and case-control studies, respectively. No obvious divergence existed among different ethnic groups. Therefore, we find diabetes a risk factor for AMD, stronger for late AMD than earlier stages. However, most of the included studies only adjusted for age and sex; we thus cannot rule out confounding as a potential explanation for the association. More well-designed prospective cohort studies are still warranted to further examine the association.     

Aspirin Use and Risk of Age-Related Macular Degeneration: A Meta-Analysis

Background

Age-related macular degeneration (AMD) is the main cause of blindness and the curative options are limited. The objective of this meta-analysis was to determine the association between aspirin use and risk of AMD.

Methods

A comprehensive literature search was performed in PubMed, Embase, Web of Science, and reference lists. A meta-analysis was performed by STATA software.

Results

Ten studies involving 171729 individuals examining the association between aspirin use and risk of AMD were included. Among the included studies, 2 were randomized-controlled trials (RCTs), 4 were case-control studies and 4 were cohort studies. The relative risks (RRs) were pooled using a random-effects model. Relative risks with 95% confidence intervals (CIs) of aspirin use as a risk for AMD. The pooled RR of 10 included studies between the use of aspirin and risk of AMD was 1.09 (95% CI, 0.96–1.24). The same result was detected in early and late stage AMD subgroup analysis. In the subgroup analyses, the pooled RR of RCTs, case-control studies and cohort studies were 0.81 (95% CI, 0.64–1.02), 1.02 (95% CI, 0.92–1.14) and 1.08 (95% CI, 0.91–1.28), respectively.

Conclusions

The use of aspirin was not associated with the risk of AMD.