Supplementation with fruit and vegetable extracts may decrease DNA damage in the peripheral lymphocytes of an elderly population

Oxidative stress, aging, antioxidant supplementation and their impact on human health: An overview

Aging is characterized by a progressive loss of tissue and organ function due to genetic and environmental factors, nutrition, and lifestyle. Oxidative stress is one the most important mechanisms of cellular senescence and increased frailty, resulting in several age-linked, noncommunicable diseases. Contributing events include genomic instability, telomere shortening, epigenetic mechanisms, reduced proteome homeostasis, altered stem-cell function, defective intercellular communication, progressive deregulation of nutrient sensing, mitochondrial dysfunction, and metabolic unbalance. These complex events and their interplay can be modulated by dietary habits and the ageing process, acting as potential measures of primary and secondary prevention. Promising nutritional approaches include the Mediterranean diet, the intake of dietary antioxidants, and the restriction of caloric intake. A comprehensive understanding of the ageing processes should promote new biomarkers of risk or diagnosis, but also beneficial treatments oriented to increase lifespan.

An encapsulated fruit, vegetable and berry juice powder concentrate increases plasma values of specific carotenoids and vitamins

Vitamins and carotenoids are organic compounds that are important for vital functions of the human organism. Since the human body is not able to synthesize most of these micronutrients, they need to be supplied by the intake of food or supplements. The aim of this study was to analyze whether a whole food based, encapsulated fruit, berry, and vegetable juice powder concentrate provides bioavailable carotenoids and vitamins A (all-trans retinol), E and C. Eighteen healthy subjects received 6 capsules a day for 8 weeks, which provided 2.91 mg β-carotene, 490 μg vitamin A, 18.7 mg vitamin E, 159 mg vitamin C, 6.1 mg lutein and 1 mg lycopene. Plasma concentrations of several carotenoids and vitamins before and after supplementation were measured. After 8 weeks of supplementation, the plasma concentration of the following carotenoids increased significantly: α-carotene increased from 59.6 ± 22.4 nmol/L to 85.7 ± 24.2 nmol/L (p = 0.002), β-cryptoxanthin from 106.7 ± 39.8 nmol/L to 151.9 ± 57.9 nmol/L (p = 0.017), and lycopene from 1.2 ± 0.5 μmol/L to 1.7 ± 0.5 μmol/L (p = 0.005). Significant increases were also observed for plasma concentrations of vitamin C from 70 ± 20 μmol/L to 90 ± 10 μmol/L (p < 0.001), all-trans retinol from 1.99 ± 0.24 μmol/L to 2.30 ± 0.66 μmol/L (p = 0.015), and α-tocopherol from 27 ± 6 μmol/L to 32 ± 6 μmol/L (p = 0.008). For those micronutrients with accepted plasma reference ranges, all observed increases levelled off around the upper limit of the individual reference range. The data demonstrate that the investigated supplement is able to increase plasma concentrations of certain carotenoids and vitamins of healthy subjects within 8 weeks.

A Systematic Review of Behavioural Interventions Promoting Healthy Eating among Older People

Because eating habits are inseparably linked with people's physical health, effective behaviour interventions are highly demanded to promote healthy eating among older people. The aim of this systematic review was to identify effective diet interventions for older people and provide useful evidence and direction for further research. Three electronic bibliographic databases-PubMed, Scopus and Web of Science Core Collection were used to conduct a systematic literature search based on fixed inclusion and exclusion criteria. English language peer-reviewed journal articles published between 2011 and 2016 were selected for data extraction and quality assessment. Finally, a total of 16 studies were identified. The studies' duration ranged from three weeks to seven years. The majority of studies were carried out in European countries. Seven studies had a moderate quality while the remaining studies were at a less than moderate level. Three dietary educational interventions and all meal service related interventions reported improvements in older people's dietary variety, nutrition status, or other health-related eating behaviours. Multicomponent dietary interventions mainly contributed to the reduction of risk of chronic disease. The results supported that older people could achieve a better dietary quality if they make diet-related changes by receiving either dietary education or healthier meal service. Further high-quality studies are required to promote healthy eating among older people by taking regional diet patterns, advanced information technology, and nudging strategies into account.

A Randomized Double-Blind Placebo-Controlled Trial of Fruit and Vegetable Concentrates on Intermediate Biomarkers in Head and Neck Cancer

Background. Head and neck cancer (HNC) patients are at an increased risk for developing second primary tumors (SPTs). Diets rich in fruits and vegetables (FVs) may lower HNC risk. FV concentrates may offer a potential alternative to increasing FV intake. Methods. We conducted a randomized, double-blind, placebo-controlled trial to evaluate whether Juice PLUS+ (JP; a commercial product with multiple FV concentrates) has an effect on p27 and Ki-67, biomarkers associated with the risk of SPTs. During 2004-2008, we randomized 134 HNC patients to 12 weeks of JP (n = 72) or placebo (n = 62). Oral cavity mucosal biopsies and whole blood were obtained at baseline and after 12 weeks. All participants were given the opportunity to receive JP for 5 years following the end of the intervention period, and they were followed yearly for the development of SPTs. Results. After 12 weeks, patients on JP had significantly higher serum α-carotene (P = .009), β-carotene (P < .0001), and lutein (P = .003) but did not differ significantly in p27 (P = .23) or Ki-67 (P = .95). JP use following the initial 12-week trial was not significantly associated with SPT prevention. Conclusions. Despite increased serum micronutrient levels, our results do not suggest a clinical benefit of JP in HNC patients. Future studies should focus on longer intervention periods and/or modified supplement formulations with demonstrated chemopreventive properties.

The Effects of Nutritional Juice Supplementation on the Extent of Climacteric Symptoms: An Observational Study

Objective. This study aims to evaluate the effect of daily dietary nutritional supplement on somatic, psychological, and urogenital symptoms in postmenopausal women. Material and Methods. In this study 28 healthy, symptomatic, peri- and postmenopausal women of 47–67 years of age were allocated to use the nutritional supplement JuicePLUS+®. Primary research parameters: Menopause Rating Scale (MRS) was used to assess menopausal symptoms at baseline and after 8 and 16 weeks of treatment. Secondary parameters: proliferation behaviour of vaginal smear was scored at baseline and after treatment. Results. Treatment with the supplement resulted in a reduction of somatic, psychological, and urogenital symptoms. The overall MRS score showed an average improvement of 44.01%. Most benefits were observed for the psychological symptoms irritability (60.55%) and physical and mental exhaustion (49.08%); modest effects were observed for hot flashes (44.86%) and sleeping problems (35.56%). There was a minor improvement in sexual problems; 6 women reported an increased libido. No statistically significant effect was found in vaginal dryness and proliferation behaviour of vaginal mucosa. No adverse effects were observed. Conclusion. Dietary nutritional supplement may constitute an effective alternative therapy to conventional alternative medicine for somatic, psychological, and sexual symptoms.

Predictors of radiation-induced gastrointestinal morbidity: A prospective, longitudinal study following radiotherapy for carcinoma of the prostate

Background Chronic gastrointestinal (GI) morbidity occurs in ≥50% of patients after external beam radiotherapy (EBRT) for carcinoma of prostate (CaP). This prospective, longitudinal study examines which baseline measurements of: 1) homocysteine and micronutrients in plasma; 2) chromosome damage/misrepair biomarkers; and 3) anal and rectal dose volume metrics predict GI morbidity after EBRT. Patients and methods In total, 106 patients with CaP had evaluations of GI symptoms (modified LENT-SOMA questionnaires) before EBRT and at one month, one, two and three years after its completion. Other variables measured before EBRT were: 1) plasma concentrations of homocysteine and micronutrients including caroteinoids and selenium; 2) chromosome damage/DNA misrepair (micronuclei/nucleoplasmic bridge) indices; and 3) mean anal and rectal wall doses and volumes of anal and rectal walls receiving ≥40 Gy and ≥60 Gy. Univariate and multivariate analyzes examined the relationships among: 1) plasma levels of homocysteine and micronutrients; 2) indices of chromosome damage/DNA misrepair; and 3) mean anal and rectal wall doses and volumes of anal and rectal walls receiving ≥40 Gy and ≥60 Gy and total GI symptom scores from one month to three years after EBRT. Results Increased frequency and urgency of defecation, rectal mucous discharge and bleeding after EBRT resulted in sustained rises in total GI symptom scores above baseline at three years. On univariate analysis, total GI symptom scores were significantly associated with: 1) plasma selenium and α tocopherol; 2) micronuclei indices of DNA damage; 3) mean anal and rectal wall doses; and 4) volumes of anal and rectal wall receiving ≥40 Gy and ≥60 Gy (p = 0.08-<0.001). On multivariate analysis, only volume of anal wall receiving ≥40 Gy was significant for increased GI symptoms after EBRT (p < 0.001). Conclusion The volume of anal wall receiving ≥40 Gy predicts chronic GI morbidity after EBRT for CaP.

Effects of a traditional fermented grape-based drink 'hardaliye' on antioxidant status of healthy adults: a randomized controlled clinical trial

BACKGROUND

The antioxidative effects of the traditional grape-based beverage, hardaliye, were investigated with a 40-day randomized controlled clinical trial on 89 healthy adults. Subjects were randomly divided into three groups: high hardaliye (HH), low hardaliye (LH) and control group. HH and LH groups consumed 500 mL and 250 mL hardaliye per day, respectively, and the control group did not consume any hardaliye. Dien conjugate (DC), malondialdehyde (MDA), vitamin C, total antioxidant capacity (TAC) and homocysteine concentrations were measured in fasting blood samples collected at baseline and after intervention.

RESULTS

Significant decreases in DC, MDA and homocysteine concentrations were observed in HH and LH groups (P < 0.001) after intervention, whereas the control group showed no change. The reduction in homocysteine was significantly different between HH and LH groups (P < 0.001), except for DC and MDA. TAC and vitamin C were slightly increased; however, the change was not statistically significant.

CONCLUSION

Dietary supplementation with hardaliye affect the MDA, DC and homocysteine levels in blood, possibly due to the presence of antioxidant compounds. Dose response was only observed for homocysteine. Further studies need to be performed to assess the effects on antioxidant capacity.

Ameliorating reactive oxygen species-induced in vitro lipid peroxidation in brain, liver, mitochondria and DNA damage by Zingiber officinale Roscoe

Iron is an essential nutrient for a number of cellular activities. However, excess cellular iron can be toxic by producing reactive oxygen species (ROS) such as superoxide anion (O(2) (-)) and hydroxyl radical (HO(·)) that damage proteins, lipids and DNA. Mutagenic and genotoxic end products of lipid peroxidation can induce the decline of mitochondrial respiration and are associated with various human ailments including aging, neurodegenerative disorders, cancer etc. Zingiber officinale Roscoe (ginger) is a widely used spice around the world. The protective effect of aqueous ethanol extract of Z. officinale against ROS-induced in vitro lipid peroxidation and DNA damage was evaluated in this study. The lipid peroxidation was induced by hydroxyl radical generated from Fenton's reaction in rat liver and brain homogenates and mitochondrial fraction (isolated from rat liver). The DNA protection was evaluated using H(2)O(2)-induced changes in pBR-322 plasmid and Fenton reaction-induced DNA fragmentation in rat liver. The results indicated that Z. officinale significantly (P<0.001) protected the lipid peroxidation in all the tissue homogenate/mitochondria. The extract at 2 and 0.5 mg/ml could protect 92 % of the lipid peroxidation in brain homogenate and liver mitochondria respectively. The percent inhibition of lipid peroxidation at 1mg/ml of Z. officinale in the liver homogenate was 94 %. However, the extract could partially alleviate the DNA damage. The protective mechanism can be correlated to the radical scavenging property of Z. officinale. The results of the study suggest the possible nutraceutical role of Z. officinale against the oxidative stress induced human ailments.

Role of dietary antioxidants in the prevention of in vivo oxidative DNA damage

Epidemiological evidence consistently shows that diets high in fresh fruit and vegetables significantly lower cancer risk. Given the postulated role of oxidative DNA damage in carcinogenesis, the assumption has been made that it is the antioxidant properties of food constituents, such as vitamin C, E and carotenoids, which confer protection. However, epidemiological studies with specific antioxidants, either singly or in combination, have not, on the whole, supported this hypothesis. In contrast, studies examining the in vitro effect of antioxidants upon oxidative DNA damage have generally been supportive, in terms of preventing damage induction. The same, however, cannot be said for the in vivo intervention studies where overall the results have been equivocal. Nevertheless, recent work has suggested that some dietary antioxidants may confer protective properties through a novel mechanism, unrelated to their conventional free-radical scavenging abilities. Upregulation of antioxidant defence, xenobiotic metabolism, or DNA-repair genes may all limit cellular damage and hence promote maintenance of cell integrity. However, until further work has clarified whether dietary supplementation with antioxidants confers a reduced risk of cancer and the mechanism by which this effect is exerted, the recommendation for a diet rich in fruit and vegetables remains valid empirically.

Can pure fruit and vegetable juices protect against cancer and cardiovascular disease too? A review of the evidence

While it is widely accepted that fruit and vegetables (F&V) lower the risk of cancer, and cardiovascular disease (CVD), the role of pure fruit and vegetable (PFV) juices is often downplayed. This review poses two questions: Are the protective benefits of F&V dependent upon constituents lacking in PFV juices (e.g. fibre)? Do PFV juices impact on disease risk when considered separately from F&V? Studies comparing the effects of fibre and antioxidants were reviewed, yielding the finding that the impact of F&V may relate more strongly to antioxidants, than to fibre. For the second question, high-quality published studies that considered PFV juices were reviewed. The impact of PFV juices on cancer risk was weakly positive, although a lack of human data and contradictory findings hampered conclusions. For CVD, there was convincing evidence from epidemiological and clinical studies that PFV juices reduced risk via a number of probable mechanisms. It was concluded that the view that PFV juices are nutritionally inferior to F&V, in relation to chronic disease risk reduction, is unjustified.

Scavenging of peroxynitrite-derived radicals by flavonoids may support endothelial NO synthase activity, contributing to the vascular protection associated with high fruit and vegetable intakes

Ample intakes of fruit and vegetables have been linked epidemiologically with reduced risk for coronary disease, stroke, hypertension, obesity, many types of cancer, chronic pulmonary disease, osteoporosis, and various ocular disorders. The favorable impact of diets rich in fruit and vegetables on coronary risk has been confirmed in meta-analyses, and is thought to be largely attributable to the folk acid and potassium supplied by these foods. Although high intakes of vitamin C appear to confer some cardiovascular protection, the amounts supplied by typical diets may be too low to be of much benefit in this regard. High flavonoid intakes emerge as protective in some epidemiological studies, albeit the dose-response pattern observed is often L-shaped - seemingly more consistent with low intakes being harmful, than with high intakes being protective. Nonetheless, flavonoids have shown anti-atherogenic activity in rodent models, and both clinical and rodent supplementation studies with foods and food extracts rich in flavonoids demonstrate improvements in endothelium-dependent vasodilation traceable to increased endothelial nitric oxide synthesis. However, flavonoids do not appear to increase the expression of endothelial NO synthase, nor do they modify endothelial superoxide production. A likely explanation is that, even in nanomolar concentrations achievable in vivo, flavonoids can act as efficient scavengers of peroxynitrite-derived radicals, thereby protecting the cofactor tetrahydrobiopterin, crucial for NO synthase activity. Studies with cultured endothelial cells should be useful for evaluating this possibility. It would also be appropriate to assess the effects of flavonoids on prostacylin synthetase activity, on endothelial catabolism of asymmetric dimethylarginine, and on signaling mechanisms that activate NO synthase. Since peroxynitrite can induce mutagenic damage to DNA, it is conceivable that scavenging of peroxynitrite-derived radicals contributes to the reduction in mutagenesis associated with high intakes of fruits and vegetables. Carotenoids also have the potential to prevent peroxynitrite-mediated damage, although, as contrasted with flavonoids, there is comparatively little evidence that these compounds are anti-atherogenic or beneficial for endothelial function; a recent meta-analysis of epidemiological studies suggests that high lutein intakes may modestly reduce coronary risk.

Oxidative stress status in an institutionalised elderly group after the intake of a phenolic-rich dessert

The elderly population undergoes a series of physiological and sociological changes common to old age with a high probability of suffering degenerative illness and malnutrition. A dessert rich in phenolic compounds has been designed by using concentrated juices of grape, cherry, blackberry, blackcurrant and raspberry with the aim of it being used as a complementary food in adulthood. In the present study, we investigated the effect of the intake of this dessert (a jar of 200 g daily for a period of 2 weeks), with an antioxidant activity equivalent to ten servings of fruits and vegetables, on several markers of oxidative and antioxidant status in DNA and plasma in a group of elderly individuals. Non-smoking institutionalised elderly subjects were recruited from a pool of volunteers in an old-age home in Murcia (Spain). Twenty-two subjects (six men and sixteen women) participated in the study. The study was designed as a randomised intervention trial with a period of 2 weeks. At days 1 and 15, blood samples were collected to analyse total antioxidant capacity, biochemical parameters, antioxidant vitamins, LDL peroxidation, and DNA damage in peripheral blood lymphocytes. The conclusion of the present study is that a 2-week intervention with our dessert enriched with natural polyphenol compounds in elderly individuals does not give enough time to find changes in the antioxidant and oxidative status. Also, the view that the marked antioxidant ability of polyphenolsin vitrodoes not translate to analogous effectsin vivowas confirmed. Moreover, a highly oxidative stress status during ageing was confirmed, together with the need to perform follow-up nutritional studies to improve this situation.

Immunity and antioxidant capacity in humans is enhanced by consumption of a dried, encapsulated fruit and vegetable juice concentrate

The daily consumption of fruits and vegetables is a common dietary recommendation to support good health. We hypothesized that a commercially available encapsulated fruit and vegetable juice powder concentrate (FVJC) could support functional indices of health due to increased intake of various phytonutrients. This was a double-blind, randomized, placebo-controlled investigation of 59 healthy law students who consumed either FVJC or placebo capsules for 77 d. Blood was collected on d 1, 35, and 77 to examine the number of circulating alphabeta- and gammadelta-T cells, cytokine production, lymphocyte DNA damage, antioxidant status, and levels of carotenoids and vitamin C. A log of illnesses and symptoms was also kept. The FVJC group tended to have fewer total symptoms than the placebo group (P < 0.076). By d 77 there was a 30% increase in circulating gammadelta-T cells and a 40% reduction in DNA damage in lymphocytes in the FVJC group relative to the placebo group. Plasma levels of vitamin C and of beta-carotene, lycopene, and lutein increased significantly from baseline in the FVJC group as did plasma oxygen radical absorptive capacity (50%). Interferon-gamma produced by phorbol-stimulated lymphocytes was reduced 70% in the FVJC group, whereas other cytokines (IL-4, IL-6, transforming growth factor beta) were unchanged relative to treatment or time. FVJC consumption during this study period resulted in increased plasma nutrients and antioxidant capacity, reduction in DNA strand breaks, and an increase in circulating gammadelta-T cells.

Efficiency of apples, strawberries, and tomatoes for reduction of oxidative stress in pigs as a model for humans

OBJECTIVE

The present study investigated the potency of apples, strawberries, and tomatoes in decreasing oxidative stress in pigs as a model for humans.

METHODS

Forty-eight growing pigs were individually penned in metabolic cages and divided into six groups. All groups received isocaloric daily rations composed of a basal diet supplemented with starch, linseed oil, linseed oil and apples, linseed oil and strawberries, linseed oil and tomatoes, or linseed oil, apples, strawberries and tomatoes. Oxidative stress was evaluated at the beginning and at the end of the 22-d experimental period by measuring the degree of DNA damage in mononuclear blood cells, the concentration of malondialdehyde (MDA) in plasma, the MDA excretion rate, the concentration of tocopherols in plasma, plasma total antioxidant status, and erythrocyte glutathione peroxidase concentration.

RESULTS

The results confirmed that the linseed oil diet significantly increased MDA formation in the body and DNA damage to mononuclear blood cells in comparison with the starch diet. Although the MDA concentration in plasma was significantly decreased in all fruit groups, urine MDA excretion rate was decreased only in the linseed oil/apple and linseed oil/apple/strawberry/tomato groups. Supplementation with fruit significantly decreased DNA damage, was more pronounced in the linseed oil/apple and linseed oil/apple/strawberry/tomato groups. Significantly lower glutathione peroxidase concentrations were observed only in the linseed oil/strawberry group.

CONCLUSIONS

Our findings support the hypothesis that supplementation with apples, strawberries, or tomatoes effectively decreases oxidative stress by decreasing MDA formation in the body and by protecting mononuclear blood cells against increased DNA damage. This effect was particularly pronounced in the group supplemented with a fruit mixture; among the single fruit supplements, the most beneficial effect was obtained with apples.

Diet and biomarkers of oxidative damage in women previously treated for breast cancer

This study sought to evaluate the relationship between dietary intake of fat, polyunsaturated fat, saturated fat, arachidonic acid, and selected dietary antioxidants and levels of oxidative damage as measured by urinary levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-epi-prostaglandin F2alpha (8-iso-PGF2alpha) in women previously treated for breast cancer. Two hundred two study subjects participating in the Women's Healthy Eating and Living (WHEL) study were included in this ancillary study. Dietary intakes and concentrations of urinary 8-OHdG and 8-iso-PGF2alpha were measured at baseline and 12 mo in the 179 women included in the analytical cohort. Study subjects demonstrated a significant reduction in dietary total, polyunsaturated, and saturated fat intake and a significant increase in vitamins E and C and beta-carotene intake from baseline to 12 mo. Linear mixed-models analysis using baseline and Year 1 data indicated that vitamin E intake was inversely associated with both 8-OHdG and 8-iso-PGF2alpha. 8-Iso-PGF2alpha is increased with increased body mass index (BMI) and polyunsaturated fatty acid (PUFA) intake, indicating an increase in lipid peroxidation with greater BMI and higher PUFA intake. 8-OHdG was inversely related to age but positively related to arachidonic acid, indicating an increase in DNA damage with higher intake of arachidonic acid (meat). The results of this nested case-controlled study provide potential mechanisms by which a high fruit and vegetable, low-fat diet might reduce the recurrence rate of or early-stage breast cancer.

Antioxidant capacity of vegetables, spices and dressings relevant to nutrition

Vegetables are the most important sources of phenolics in the Mediterranean diet. Phenolics, especially flavonoids, are suggested as being essential bioactive compounds providing health benefits. In this study, twenty-seven vegetables, fifteen aromatic herbs and some spices consumed in Central Italy (the Marches region) were studied to reveal total phenolic, flavonoid and flavanol content as well as their antioxidant capacity measured by the oxygen radical absorbance capacity (ORAC) method. A comparison in terms of antioxidant capacity was made between different salads, as well as between salads to which aromatic herbs had been added. Lemon balm and marjoram at a concentration of 1.5 % w/w increased by 150 % and 200 % respectively the antioxidant capacity of a salad portion. A 200 g portion of a salad enriched with marjoram corresponded to an intake of 200 (SD 10) mg phenolics and 4000 (SD 300) ORAC units (micromol Trolox equivalents). Olive oils and wine or apple vinegars were the salad dressings that provided the highest increase in antioxidant capacity. Among the spices tested, cumin and fresh ginger made the most significant contribution to the antioxidant capacity. The results are useful in surveying the antioxidant parameters of vegetables, herbs and spices produced and consumed in our geographical area as well as in quantifying the daily intake of phenolics and ORAC units. The results can be used in public health campaigns to stimulate the consumption of vegetables able to provide significant health protection in order to prevent chronic diseases.

Health promotion by flavonoids, tocopherols, tocotrienols, and other phenols: direct or indirect effects? Antioxidant or not?

Foods and beverages rich in phenolic compounds, especially flavonoids, have often been associated with decreased risk of developing several diseases. However, it remains unclear whether this protective effect is attributable to the phenols or to other agents in the diet. Alleged health-promoting effects of flavonoids are usually attributed to their powerful antioxidant activities, but evidence for in vivo antioxidant effects of flavonoids is confusing and equivocal. This may be because maximal plasma concentrations, even after extensive flavonoid intake, may be low (insufficient to exert significant systemic antioxidant effects) and because flavonoid metabolites tend to have decreased antioxidant activity. Reports of substantial increases in plasma total antioxidant activity after flavonoid intake must be interpreted with caution; findings may be attributable to changes in urate concentrations. However, phenols might exert direct effects within the gastrointestinal tract, because of the high concentrations present. These effects could include binding of prooxidant iron, scavenging of reactive nitrogen, chlorine, and oxygen species, and perhaps inhibition of cyclooxygenases and lipoxygenases. Our measurements of flavonoids and other phenols in human fecal water are consistent with this concept. We argue that tocopherols and tocotrienols may also exert direct beneficial effects in the gastrointestinal tract and that their return to the gastrointestinal tract by the liver through the bile may be physiologically advantageous.

Dietary supplementation with a natural carotenoid mixture decreases oxidative stress

OBJECTIVE

To determine whether dietary supplementation with a natural carotenoid mixture counteracts the enhancement of oxidative stress induced by consumption of fish oil.

DESIGN

A randomised double-blind crossover dietary intervention.

SETTING

Hugh Sinclair Unit of Human Nutrition, School of Food Biosciences, The University of Reading, Whiteknights PO Box 226, Reading RG6 6AP, UK.

SUBJECTS AND INTERVENTION

A total of 32 free-living healthy nonsmoking volunteers were recruited by posters and e-mails in The University of Reading. One volunteer withdrew during the study. The volunteers consumed a daily supplement comprising capsules containing fish oil (4 x 1 g) or fish oil (4 x 1 g) containing a natural carotenoid mixture (4 x 7.6 mg) for 3 weeks in a randomised crossover design separated by a 12 week washout phase. The carotenoid mixture provided a daily intake of beta-carotene (6.0 mg), alpha-carotene (1.4 mg), lycopene (4.5 mg), bixin (11.7 mg), lutein (4.4 mg) and paprika carotenoids (2.2 mg). Blood and urine samples were collected on days 0 and 21 of each dietary period.

RESULTS

The carotenoid mixture reduced the fall in ex vivo oxidative stability of low-density lipoprotein (LDL) induced by the fish oil (P=0.045) and it reduced the extent of DNA damage assessed by the concentration of 8-hydroxy-2'-deoxyguanosine in urine (P=0.005). There was no effect on the oxidative stability of plasma ex vivo assessed by the oxygen radical absorbance capacity test. beta-Carotene, alpha-carotene, lycopene and lutein were increased in the plasma of subjects consuming the carotenoid mixture. Plasma triglyceride levels were reduced significantly more than the reduction for the fish oil control (P=0.035), but total cholesterol, HDL and LDL levels were not significantly changed by the consumption of the carotenoid mixture.

CONCLUSIONS

Consumption of the natural carotenoid mixture lowered the increase in oxidative stress induced by the fish oil as assessed by ex vivo oxidative stability of LDL and DNA degradation product in urine. The carotenoid mixture also enhanced the plasma triglyceride-lowering effect of the fish oil.

SPONSORSHIP

: The study was supported by funding from the Greek Studentship Foundation and from Unilever Bestfoods plc. Carotenoids were contributed by Overseal Foods plc.

Garlic and aging: new insights into an old remedy

There has been an impressive gain in individual life expectancy with parallel increases in age-related chronic diseases of the cardiovascular, brain and immune systems. These can cause loss of autonomy, dependence and high social costs for individuals and society. It is now accepted that aging and age-related diseases are in part caused by free radical reactions. The arrest of aging and stimulation of rejuvenation of the human body is also being sought. Over the last 20 years the use of herbs and natural products has gained popularity and these are being consumed backed by epidemiological evidence. One such herb is garlic, which has been used throughout the history of civilization for treating a wide variety of ailments associated with aging. The role of garlic in preventing age-related diseases has been investigated extensively over the last 10-15 years. Garlic has strong antioxidant properties and it has been suggested that garlic can prevent cardiovascular disease, inhibit platelet aggregation, thrombus formation, prevent cancer, diseases associated with cerebral aging, arthritis, cataract formation, and rejuvenate skin, improve blood circulation and energy levels. This review provides an insight in to garlic's antioxidant properties and presents evidence that it may either prevent or delay chronic diseases associated with aging.

Effect of diet on cancer development: is oxidative DNA damage a biomarker?

Free radicals and other reactive species are generated in vivo and many of them can cause oxidative damage to DNA. Although there are methodological uncertainties about accurate quantitation of oxidative DNA damage, the levels of such damage that escape immediate repair and persist in DNA appear to be in the range that could contribute significantly to mutation rates in vivo. The observation that diets rich in fruits and vegetables can decrease both oxidative DNA damage and cancer incidence is consistent with this. By contrast, agents increasing oxidative DNA damage usually increase risk of cancer development. Such agents include cigarette smoke, several other carcinogens, and chronic inflammation. Rheumatoid arthritis and diabetes are accompanied by increased oxidative DNA damage but the pattern of increased cancer risk seems unusual. Other uncertainties are the location of oxidative DNA damage within the genome and the variation in rate and level of oxidative damage between different body tissues. In well-nourished human volunteers, fruits and vegetables have been shown to decrease oxidative DNA damage in several studies, but data from short-term human intervention studies suggest that the protective agents are not vitamin C, vitamin E, beta-carotene, or flavonoids.

Vitamin C and genomic stability

Vitamin C, a water-soluble glucose derivative, has considerable antioxidant activity in vitro, in part because of its ease of oxidation and because the semidehydroascorbate radical derived from it is of low reactivity. Vitamin C in vivo is an essential cofactor for a range of enzymes involved in diverse metabolic pathways, but much recent literature has focused on its antioxidant effects. Consumption of foods rich in Vitamin C (fruits and vegetables) is associated with decreased risk of cardiovascular disease, of many types of cancer and possibly of neurodegenerative disease, but the extent to which Vitamin C contributes to these effects is uncertain. Data using biomarkers of oxidative damage to DNA bases have given no compelling evidence to date that ascorbate supplements can decrease the levels of oxidative DNA damage in vivo, except perhaps in subjects with very low Vitamin C intakes. Similarly, there is no conclusive evidence from studies of strand breaks, micronuclei, or chromosomal aberrations for a protective effect of Vitamin C. There is limited evidence that supplements of Vitamin C might have beneficial effects in disorders of vascular function, and that diet-derived Vitamin C may decrease gastric cancer incidence in certain populations, but it is not clear whether it is the antioxidant or other properties of ascorbate that are responsible for these two actions.