Showing papers by "Iris F.F. Benzie published in 2004"

Ganoderma lucidum (‘Lingzhi’), a Chinese medicinal mushroom: biomarker responses in a controlled human supplementation study

Abstract: Lingzhi (Ganoderma lucidum) is a woody mushroom highly regarded in traditional medicine and is widely consumed in the belief that it promotes health and longevity, lowers the risk of cancer and heart disease and boosts the immune system. However, objective scientific validation of the putative health benefits of Lingzhi in human subjects is lacking, and issues of possible toxicity must be addressed. The present double-blinded, placebo-controlled, cross-over intervention study investigated the effects of 4 weeks Lingzhi supplementation on a range of biomarkers for antioxidant status, CHD risk, DNA damage, immune status, and inflammation, as well as markers of liver and renal toxicity. It was performed as a follow-up to a study that showed that antioxidant power in plasma increased after Lingzhi ingestion, and that 10 d supplementation was associated with a trend towards an improved CHD biomarker profile. In the present study, fasting blood and urine from healthy, consenting adults (n 18; aged 22-52 years) was collected before and after 4 weeks supplementation with a commercially available encapsulated Lingzhi preparation (1.44 g Lingzhi/d; equivalent to 13.2 g fresh mushroom/d) or placebo. No significant change in any of the variables was found, although a slight trend toward lower lipids was again seen, and antioxidant capacity in urine increased. The results showed no evidence of liver, renal or DNA toxicity with Lingzhi intake, and this is reassuring. The present study of the effects in healthy, well-nourished subjects provides useful, new scientific data that will support controlled intervention trials using at-risk subjects in order to assess the therapeutic effect of Lingzhi in the promotion of healthy ageing.

Vitamins C and E: acute interactive effects on biomarkers of antioxidant defence and oxidative stress.

Abstract: Oxidative stress is implicated in the aetiology of many diseases; however, most supplementation trials with antioxidant micronutrients have not shown expected beneficial effects. This randomized, double-blinded, placebo-controlled study evaluated acute effects (at 90, 180min and 24h [fasting] post-ingestion) of single doses of Vitamins C (500mg) and E (400IU), alone and in combination, on biomarkers of plasma antioxidant status, lipid peroxidation and lymphocyte DNA damage in 12 healthy, consenting volunteers. Plasma ascorbic acid increased significantly (P < 0.01) within 2h of ingestion of Vitamin C, and alpha-tocopherol was significantly (P < 0.01) higher at 24h post-ingestion Vitamin E. The pattern of response was not significantly different whether Vitamin C (or Vitamin E) was taken alone or in combination, indicating no augmentation of response to one by co-ingestion of the other vitamin. No significant changes were seen in plasma FRAP in the group overall (although increases (P < 0.05) were seen at 90 and 180min post-ingestion in women after Vitamin C ingestion) or in MDA across treatments, and no evidence of increased DNA damage, or of DNA protection, was seen at any time point after Vitamin C and/or E ingestion. In conclusion, the data from this first controlled study of acute effects of single doses of Vitamin C and/or E show no evidence of either a protective or deleterious effect on DNA damage, resistance of DNA to oxidant challenge, or lipid peroxidation. No evidence of a synergistic or cooperative interaction between Vitamins C and E was seen, but further study is needed to determine possible interactive effects in a staggered supplementation cycle, and study of subjects under increased oxidative stress or with marginal antioxidant status would be useful. It would be of interest also to study the effects of these vitamins ingested with, or in, whole food, to determine if they are directly protective at doses above the minimum required to prevent deficiency, if combinations with other food components are needed for effective protection, or if Vitamins C and E are largely surrogate biomarkers of a 'healthy' diet, but are not the key protective agents.

Ganoderma lucidum ('Lingzhi'); acute and short-term biomarker response to supplementation

Abstract: Ganoderma lucidum (Lingzhi) is a popular Chinese herb with an impressive array of reputed health benefits, including antioxidant properties However, these require scientific validation The aim of this study was to investigate in vitro antioxidant capacity of Lingzhi, absorption and systemic distribution of Lingzhi antioxidants, and effects of short-term (10 days) supplementation on biomarkers of antioxidant status, coronary heart disease (CHD) risk and DNA damage In this double-blinded, placebo-controlled, cross-over intervention study, blood and urine samples were collected from 10 healthy volunteers at 0 (fasting) and 45, 90, 135 and 180 min post-ingestion of a single dose (11g) of Lingzhi Repeat fasting samples were collected after 10 days' supplementation with 072 g/d Lingzhi The acute response (up to 3 hours) was also investigated with a larger dose (33 g) of Lingzhi (n=7) Results showed that the total antioxidant capacity (as the FRAP value) of an aqueous suspension of Lingzhi was 360 micromol/g Ingestion of Lingzhi caused a significant post-ingestion increase (mean+/-SEM 23+/-3 micromol/L; P<005) in plasma antioxidant capacity, with peak response at 90 min Average increase of 29+/-11% (P<005) in urine antioxidant capacity was seen within 3 hours of ingestion After 10 days' supplementation with 072 g per day of Lingzhi, fasting plasma lipid standardised alpha-tocopherol concentration and urine antioxidant capacity increased (P<005) Fasting plasma ascorbic acid and total alpha-tocopherol concentrations and erythrocyte SOD and GPx activities increased slightly but non-significantly with supplementation Plasma lipids and uric acid tended to decrease, but changes were not statistically significant No discernable differences were seen in other variables measured Results indicate that Lingzhi intake causes an acute increase in plasma antioxidant capacity No deleterious effects on measured variables were seen The pattern of biomarker response after supplementation indicated possible benefit in terms of antioxidant status and CHD risk, but further study is needed to elucidate the nature and longer-term effects of the absorbable antioxidants from Lingzhi

Effect of one overnight wear of orthokeratology lenses on tear composition

Abstract: Purpose. To evaluate the effect of one night of orthokeratology lens wear on ocular surface health based on the changes in tear components, including ascorbate, urate, lactate dehydrogenase (LD), lactoferrin, lipocalin, lysozyme, secretory immunoglobulin A (sIgA), and serum albumin. Methods. Changes in tear components in eight healthy young men before and after 7-h overnight ortho-k lens wear were studied. Subjects attended on two separate occasions during a 1-week period, on one occasion wearing lens overnight and on the other wearing no lens. Tears (yawn-induced) were collected by capillary tube before lens fitting and on awakening. Tear ascorbate and urate were measured by high-performance liquid chromatography; LD was measured by a commercial kit method; tear proteins were measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Results. Ascorbate, sIgA, albumin, and LD increased significantly overnight with and without overnight lens wear (p 0.05). Without lens wear, tear ascorbate, sIgA, albumin, and LD increased by 21%, 34%, 9-fold, and 13-fold, respectively (p < 0.05). With ortho-k lens wear, significant flattening of the apical curvature was observed as expected, and the increases in tear ascorbate, sIgA, albumin, and LD (increases were 56%, 76%, 13-fold, and 14-fold, respectively) were significantly (p < 0.05) greater than with no lens. There was significant correlation seen between changes in albumin and LD with (r = 0.762; p = 0.037) and without (r = 0.738; p = 0.046) ortho-k lens wear. Conclusions. The result of tear ascorbate suggests that corneal cell disturbance is small after one night of ortho-k lens wear. The marked increases in albumin and LD suggest that the ocular surface is under additional hypoxic stress during overnight ortho-k lens wear.

Is ascorbate in human tears from corneal leakage or from lacrimal secretion

Abstract: BACKGROUND: This study investigated whether fresh main lacrimal gland secretion contains ascorbate, with a view to providing indirect evidence of an immediate source of this antioxidant in tears. Our hypothesis was that, if the source is corneal leakage, continuous tearing or rinsing of the eye will result in a marked decrease, by dilution, in ascorbate concentration in the reflex tears collected. Alternatively, the ascorbate concentration will be relatively constant if the main lacrimal gland secretion is the main immediate source. METHODS: Five successive samples of yawn-induced reflex tears were collected from the same eye of each of 42 subjects. In 36 of these volunteers, the testing eye was then flushed with 10 ml of saline and a sixth tear sample ('post-flush') was collected immediately. Tear ascorbate concentrations were measured using a validated high performance liquid chromatography method. RESULTS: The ascorbate concentration of the first sample (baseline) was slightly but significantly (P < 0.0001) lower (17.3 +/- 8.9 micro M) than the four subsequent samples in all subjects (average 21.4 microM). Ascorbate concentrations of post-flush samples were very similar to pre-flush values. Mean +/- SD ascorbate concentrations of pre- and post-flush samples were, respectively, 22.5 +/- 10.9 and 17.3 +/- 5.8 microM. DISCUSSION: Results show that ascorbate is present in fresh reflex tears. Data do not support the view that the cornea is the source of tear ascorbate in healthy eyes. Rather, results indicate that ascorbate is present in main lacrimal gland secretion and that this antioxidant is depleted in basal tears. Measurement of tear ascorbate may offer useful information regarding antioxidant supply to and protection of the cornea.

Viability of porcine corneal epithelium ex vivo and effect of exposure to air: a pilot study for a dry eye model.

Abstract: Purpose: To explore the use of an ex vivo, in situ porcine cornea as a model for dry eye (exposure keratitis). Methods: Twenty-seven porcine eyes were obtained from freshly killed animals at the local abattoir. The viability of 9 corneas (control-baseline group) was assessed within 5 minutes after enucleation on site. A further 18 eyes were transported to the laboratory, where they were exposed to ambient conditions for 4 hours (experimental group A, 6 eyes),for 6 hours (experimental group B, 6 eyes), and for 4 hours with wetting with Dulbecco Phosphate-Buffered Saline every 5 minutes (exposure control group, 6 eyes). All corneas were assessed by trypan blue exclusion for cell viability. Results: The number of dead cells in the central region was significantly greater than those in the peripheral region (P < 0.05) in all groups. The number of dead cells in both corneal areas increased significantly (P < 0.05) in the experimental groups with time of exposure, but there was no significant increase in the exposure control group. Conclusion: Preliminary data on the number of dead cells in porcine corneal epithelium after enucleation and the effect of exposure were obtained. It was found that after exposure to air, the corneal cells were maintained well by regular wetting, but there was progressively greater cell damage with exposure without wetting. These baseline data will be useful for the further development of the porcine dry eye model to investigate exposure keratitis.

A novel porcine dry eye model system (pDEM) with simulated lacrimation/blinking system: preliminary findings on system variability and effect of corneal drying.

Abstract: Purpose. To investigate inter- and intra-system variations and the effect of corneal drying using a recently developed pDEM. Methods. pDEM was used to simulate “normal” and “dry eye” conditions using two “lacrimation-blink” intervals (20 s and 60 s). Corneas were examined/graded with sodium fluorescein before and after the experiment. At the end of each experiment, corneas were assessed by trypan blue exclusion technique. Two duplicated pDEM systems were set up and tested to investigate reproducibility. Results. There was no significant difference in the results produced by the two pDEM systems. In the eyes under “normal” condition, there was no significant increase in the fluorescein grading. However, in eyes under “dry eye” condition, fluorescein staining increased and the number of non-viable cells in the central cornea increased. Conclusions. This novel pDEM system provides a useful assessment tool for the study of causative factors and new treatment strategies for dry eye syndrome.

Diet and health: Nursing perspective for the health of our aging population

Abstract: For most age-related disorders there is no cure, and treatment is expensive and often ineffective. Thus, disease prevention is an issue of increasing concern and importance. Nurses form the largest professional healthcare group in the world, and the professional code of the modern day nurse advocates health promotion as a primary role. Nurses, by virtue of their close, direct interaction with their community and clients, are in a strong position to disseminate and reinforce the message of health promotion with the aim of achieving functional longevity in our aging population. This requires that nurses themselves increase their awareness, knowledge and understanding of relevant interdisciplinary research findings. In the current review, the influence of diet on the risk of four of the most prevalent age-related diseases (cancer, cardiovascular disease, dementia and diabetes) is presented, and the underlying mechanisms of influence are discussed, with particular focus on antioxidant-rich foods.