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International Updates

Nutrition

Issue 57

JADAYIL, TUKAN and TAKRURI, Department of Nutrition and Food Technology, Faculty of Agriculture, University of Jordan, Amman have investigated the bioavailability of iron from four different local food plants in Jordan.
Methods: The bioavailability of iron from local plants (black cumin seeds, milk thistle seeds, sesame seeds and thyme leaves) was investigated. Apparent absorption of iron was calculated by subtracting faecal iron from iron intake in Sprague-Dawley rats. Two trials of animal feeding were performed. Liver and serum concentrations of iron and serum haemoglobin concentration were taken as response parameters for the bioavailability. Dry thyme was particularly rich in iron (117.2mg/100g dry matter) and milk thistle seeds in crude fibre (25g/100g dry matter). Diets were also supplemented with egg white.
Results: Rats fed the dry thyme diet or that supplemented with 5% egg white died but when the diet was supplemented with 10% egg white, the animals survived. Iron intake and apparent and total iron absorption were highest for the rats fed the dry thyme-egg white diet. Liver weights for the groups fed black cumin seeds and dry thyme were significantly higher (p<0.05) than those for the groups fed milk thistle and sesame seeds. Liver content of iron was highest for the animals fed black cumin seeds. Serum iron content increased significantly (p<0.05) for the animals fed black cumin seeds, and serum haemoglobin concentration increased significantly (p<0.05) in the groups fed milk thistle seed and black cumin seed diets, but decreased for the group fed the thyme-egg white diet.
Conclusions: The authors concluded that iron was better utilized from black cumin seeds as indicated by liver storage of iron. On the other hand, thyme had the highest iron absorption but lowest utilization.
Jadayil SA et al. Bioavailability of iron from four different local food plants in Jordan. Plant Foods for Human Nutrition 54(4): 285-94. 1999.

Issue 56

AYAORI and colleagues, First Department of Internal Medicine, National Defence Medical College, Saitama, Japan. Ayaori@med5.kufm.kagoshima-u.ac.jp reported on the levels and status of plasma ascorbic acid and lipid peroxidation in smoking.
Background: Active and passive smoking are considered risk factors for a variety of diseases. Plasma vitamin C levels (ascorbic acid) and lipid peroxidation status provide evidence of cellular oxidative stress and are used in this study to indicate the risks of smoking.
Methods: In this case-control study, 3 groups of healthy males were compared for their plasma vitamin C and lipid peroxidation status. The groups were: 75 active smokers (>15 cigarettes daily for >5 years), 36 passive smokers (>10 hours a week exposure to cigarette smoke) and non-smokers (no cigarette smoke exposure). Measurements made were plasma levels of ascorbic acid (AA), its redox status (ratio of dehydroascorbate (DHAA) to total AA), the levels of thiobarbiturate reactive substance (TBARS) and lipid peroxides (LPO).
Results: There were significantly lower plasma AA levels in active smokers compared to the combined non-smoking groups (p<0.05) and ratio of DHAA to total AA was significantly higher in the active and passive smokers compared to the non-smokers (p<0.05). All other measurements were comparable between groups.
Conclusions: Passive smoking, as well as direct inhalation of cigarette smoke, affects the redox status of plasma AA, suggesting oxidative stress.
Ayaori M et al. Plasma levels and redox status of ascorbic acid and levels of lipid peroxidation products in active and passive smokers. Environmental Health Perspectives 108(2): 105-8. Feb 2000.

Issue 55

EGGER and colleagues, School of Health Sciences, Deakin University, Melbourne, Victoria, Australia. eggergj@ozemail.com.au  review the evidence (69 references) regarding the effectiveness of non-prescription weight loss supplements.
Methods: The authors conducted a detailed literature search including all relevant medical and supplementary databases and evidence from manufacturers. The authors considered the theoretical basis and rationale regarding each substance, as well as available research regarding its efficacy and potential risks. The level of evidence was classified according to the main research studies for each substance.
Results: There was no good evidence for weight loss benefits from most of the substances reviewed by the authors; however there was evidence supporting mild effects of capsaicin, caffeine and fibre, but only in whole foods. In certain cases, e.g. chitosan there is a plausible theoretical basis for the product, but no supporting proof of effect in humans in the absence of a calorie-controlled diet. Potential synergistic effects of different ingredients cannot be dismissed, but can’t be assessed from current data.
Conclusions: There is an absence of good quality research regarding many substances, which means that advertising claims may be misleading.
Egger G et al. The effectiveness of popular, non-prescription weight loss supplements. The Medical Journal of Australia 171(11-12): 604-8. 6-20 Dec 1999.

MARTIN and colleagues, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts 02111 USA. amartin@hnrc.tufts.edu  studied the effects of diet and vitamins E and C on brain function.
Background: The authors write that age-related neurodegenerative conditions are the main causes of declining cognitive and motor function during ageing. Research shows that fruits and vegetables containing generous amounts of antioxidants are vital for neurological function.
Methods: The authors studied, in rats, the effect of diets enriched with fruits or vegetables but low in vitamin E and a diet high in vitamin E on vitamins C and E distribution in the brain and dopamine release over 8-months.
Results: The low-vitamin E diet resulted in lowered alpha-tocopherol levels in brain and peripheral tissues, whereas animals receiving a diet enriched in vitamin E demonstrated a significant increase, of between 500-900%. Vitamin C concentration in plasma, heart and liver was decreased in the vitamin E-supplemented group. Supplementation or depletion of alpha-tocopherol for 8 months results in marked changes in vitamin E levels in brain and peripheral tissues, and varied distribution of alpha-tocopherol throughout differing regions of the brain. Additionally, compared to controls, those rats supplemented with strawberry, spinach or vitamin E demonstrated a significant enhancement in striatal dopamine release.
Conclusions: These results suggest that nutrients in fruits and vegetables, and antioxidants, may be important for brain function.
Martin A et al. Effect of fruits, vegetables, or vitamin E-rich diet on vitamins E and C distribution in peripheral and brain tissues: implications for brain function. The Journals of Gerontology. Series A, biological Sciences and Medical Sciences 55(3): B144-51. Mar 2000.

TORNWALL and colleagues, National Public Health Institute, Helsinki, Finland studied the association between dietary/lifestyle factors and intermittent claudication (severe pain in calves due to lack of blood supply).
Methods: The authors used a cohort comprised of 26,872 male smokers aged 50-69 years, originally recruited to the Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, who were free of claudication at the beginning of the study. At baseline (1985-88), participants completed a diet history questionnaire. During the median follow-up period of 4 years ending in spring 1993, 2578 men reported symptoms of claudication. Smoking status was assessed at 4 monthly intervals.
Results: Smoking, systolic blood pressure, serum total cholesterol and diabetes mellitus were positively associated with claudication risk. Serum high density lipoprotein (HDL) cholesterol, education and exercise were inversely associated. Dietary carbohydrates, fibre and n-6 polyunsaturated fatty acids inversely affected risk, as well as the following antioxidants: dietary vitamin C (highest quartile vs. lowest: relative risk (RR) = 0.86; dietary gamma-tocopherol (RR = 0.89); dietary carotenoids (RR – 0.82); serum alpha-tocopherol (RR = 0.88); and serum beta-carotene (RR – 0.77). Cessation of smoking reduced subsequent risk for claudication (RR = 0.86).
Conclusions: Classical risk factors for atherosclerosis are associated with claudication. High intakes of antioxidant vitamins may be protective. Further research is required before antioxidants may be recommended for the prevention of intermittent claudication.
Tornwall ME et al. Prospective study of diet, lifestyle, and intermittent claudication in male smokers. American Journal of Epidemiology 151(9): 892-901. 1 May 2000.

Comments: This result may have important applications for clinical practice.

ELMADFA and PARK, Institute of Nutritional Science, University of Vienna, Austria. Ernaehrungswissenschaften@uni.vie.ac  at compared the effects of corn oil and olive/sunflower oil upon DNA damage.
Background: Plant fats and oils are major sources of mono- and polyunsaturated fatty acids, and vitamin E, the major fat-soluble antioxidant in human nutrition. Dietary antioxidants are anticipated to reduce risk of cancer by minimizing DNA damage.
Methods: The authors conducted a double-blind, study with 20 normal healthy non-smoking males aged 19-31 years. There was a 2-week adjustment period and two 2-week test periods in which diets containing 30% energy as fat included either 80g corn oil (CO) (20 mg alpha-tocopherol, 100 mg gamma-tocopherol) or 80 g olive/sunflower oil (OSO) (24 mg alpha-tocopherol, 2.4 mg gamma-tocopherol). They assessed frequency of sister chromatid exchange (SCE), an indicator of DNA damage. Blood samples for analysis of SCE rate and content of tocopherols were drawn at the beginning (T0), after the adjustment period (T1) and following the test period (T2) in 2 week intervals.
Results: After 2 weeks of corn oil diet, plasma concentration of gamma-tocopherol increased; alpha-tocopherol decreased significantly compared to the olive/sunflower oil diet. Concentration of alpha-tocopherol increased and gamma-tocopherol decreased after the olive/sunflower oil diet. Intake of the corn oil diet was associated with reduced SCE rate and intensity, there no change in SCE with the olive/sunflower oil diet.
Conclusions: The combination of gamma-tocopherol with alpha-tocopherol in the corn oil diet despite the lower alpha-tocopherol equivalents/diene acid equivalents ratio achieved better protection against DNA damage than alpha-tocopherol alone in the olive/sunflower oil diet.
Elmadfa I and Park E. Impact of diets with corn oil or olive/sunflower oils on DNA damage in healthy young men. European Journal of Nutrition 38(6): 286-92. Dec 1999.

CRAIG and colleagues, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109 USA studied how days with atypical food intake affect estimates of usual nutrient intake from 4-day food records.
Methods: The authors collected secondary analyses of 4-day food records (4DFRs) (n = 2560) collected from 1090 women aged 50 to 79 years, from the Women’s Trial Feasibility study in Minority Populations, a randomized dietary intervention trial. Food records were considered as atypical if participants marked one or more day’s food intake as ‘more’ or ‘less’ than usual. Total amounts and nutrient densities were examined for all macronutrients, fibre, vitamin C, beta-carotene and calcium. A number of statistical analyses were carried out to identify differences between nutrient intake between typical and atypical intake days.
Results: About 16% of records included at least 1 atypical day. Reporting less-than-usual intake was associated with younger age, higher income and higher body mass index. Black women were less likely to report more-than-usual intake than whites and Hispanics. Records with less-than-usual intake had lower intakes of all nutrients analyzed except alcohol; however there were nutrient density differences. Records with more-than-usual intake had higher intakes of alcohol and all nutrients except beta-carotene and vitamin C, with higher nutrient density measures of alcohol and decreased nutrient density measures of protein, vitamin C and fibre.
Conclusions: Atypical intake days are common in 4DFRs, which have a large effect upon mean total intakes of most nutrients. It is important for researchers to collect information regarding atypical intake days included in a 4-day food record. Strategies are required to incorporate such information when analyzing and interpreting research results.
Craig MR et al. The prevalence and impact of ‘atypical’ days in 4-day food records. Journal of the American Dietetic Association 100(4): 421-7. Apr 2000.

Issue 54

SINCLAIR, Green Valley Health, Hagerstown, MD 21742 USA reviews (68 references) environmental and nutritional factors involved in male infertility.
Discussion: Research confirms that male sperm counts are declining, and that environmental factors, including pesticides, exogenous oestrogens and heavy metals may negatively affect spermatogenesis. Various nutritional supplements have been shown to improve sperm counts and sperm motility, including carnitine, arginine, zinc, selenium and vitamin B-12. Numerous antioxidants have also proven beneficial in treating male infertility, including vitamins C, E glutathione, and coenzyme Q10. Acupuncture, in addition to specific botanical medicines have been documented in several studies as having a positive effect on sperm parameters. A multi-faceted therapeutic approach to improve male fertility involves the identification of harmful environmental and occupational risk factors, and the correction of underlying nutritional imbalances to encourage optimal sperm production and function.
Sinclair S. Male infertility: nutritional and environmental considerations. Alternative Medicine Review 5(1): 28-38. Feb 2000.

Comments: For further elucidation on this subject, please read the cover story Toxic Chemical Overload on page 27.

VALKONEN and KUUSI, Department of Medicine, University of Helsinki, Helsinki, Finland studied whether the acute atherogenic effects of secondhand cigarette smoke could be prevented by the effective free radical scavenger, vitamin C.
Background: During passive smoking the body is attacked by an excess of free radicals inducing oxidative stress. In nonsmoking people, even a short period of passive smoking breaks down serum antioxidant defence (TRAP) and accelerates lipid peroxidation, leading to the accumulation of their low-density lipoprotein (LDL) cholesterol in cultured human macrophages.
Methods: Blood samples were collected from nonsmoking individuals (n = 10) as they were consecutively exposed to normal air or cigarette smoke during four separate days. During the last two days, a single dose of vitamin C (3 g) was given, which doubled its plasma concentration.
Results: Vitamin C did not influence the plasma antioxidant defense of the resistance of LDL to oxidation in normal air, but prevented the smoke-induced decrease in plasma TRAP, decrease in the resistance of LDL to oxidation and the accelerated formation of serum thiobarbituric acid reactive substances (TBARS) otherwise observed 1.5 hours after the beginning of passive smoking.
Conclusions: Vitamin C protected nonsmoking subjects against the harmful effects of free radicals during exposure to secondhand smoke.
Valkonen MM and Kuusi T. Vitamin C prevents the acute atherogenic effects of passive smoking. Free Radical Biology and Medicine 28(3): 428-36. 1 Feb 2000.

Issue 53

MA and colleagues, Department of Nutritional Science and Dietetics, University of Nebraska, Lincoln, and Department of Nutrition, Arizona State University, Tempe write that cigarette smoking is a major risk factor for several chronic oxidative diseases which can be relieved with antioxidants. The authors identified typical dietary intake and major food group contributors of antioxidants beta-carotene, vitamins C and E by smoking status.
Methods: The authors used the continuing 1994-96 Survey of Food Intakes by Individuals (CSFII) for the current sample (n = 6749) who were categorized as non (n = 3231), former (n = 1684) and current (n = 1834 smokers). Food intakes were estimated using two 24-hour dietary recall questionnaires.
Results: The sample was composed of 3707 men and 3042 women. Current smokers tended to be younger with less education and lower incomes than nonsmokers and former smokers. Average body mass index (kg/m(2)) of current smokers was 25.8, the lowest of the 3 groups. Current smokers had the lowest dietary antioxidant intake. Compared to the other 2 groups, fatty foods such as luncheon meats, condiments and salad dressings and ground beef contributed more to the antioxidant intakes of current smokers, and fruit and vegetables contributed less. Current smokers consumed the fewest numbers of servings of all nutrient-bearing groups in the food guide pyramid, except the meat group.
Conclusions: Future studies needs to target the clustering of cigarette smoking and other unhealthy lifestyle habits such as imprudent diet.
Ma J et al. Antioxidant intakes and smoking status: data from the continuing survey of food intakes by individuals 1994-1996. The American Journal of Clinical Nutrition 71(3): 774-80. Mar 2000.

CHRISTEN and colleagues, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA USA assessed the benefits and risks of supplementation with beta-carotene, vitamin E, vitamin C and multivitamins upon cancer, cardiovascular (CVD) and eye diseases.
Methods: Physicians’ Health Study II (PHS II) is a randomized, double-blind, placebo-controlled trial using 15,000 willing and eligible physicians aged 55 years and older. PHS II will test alternate day beta-carotene, alternate day vitamin E, daily vitamin C and a daily multivitamin in the prevention of total and prostate cancer, CVD, age-related eye diseases, cataract and macular degeneration.
Prior Results: PHS I (randomized, double-blind, placebo-controlled trial with 22,071 US male physicians) showed that beta-carotene supplementation (50 mg, alternate days) had no significant benefit or harm on cancer or CVD during more than 12 years of treatment and follow-up. For cancer, there were possible benefits with total and prostate cancer in people with low baseline levels of beta-carotene, a result in line with the Chinese Cancer Prevention Study in a poorly nourished population. For CVD there were apparent benefits of beta-carotene supplementation among a small subgroup of 333 men with prior angina or revascularization. Data from randomized trials of primary prevention are sparse and inconsistent for vitamin E and non-existent for vitamin C and multivitamins. There are no completed large-scale randomized trials of antioxidant vitamins for eye diseases.
Conclusions: PHS II is the only primary prevention trial with apparently healthy men testing for benefits and risks of vitamin E on cancer and CVD, of vitamin C, multivitamins and single antioxidants alone and in combination, on cancer, CVD and eye diseases. Additionally, PHS II is the only trial testing the hypotheses that beta-carotene and vitamin E may reduce the risks of prostate cancer. Therefore, PHS II will add unique and important relevant information to the totality of evidence regarding the benefits and risks of beta-carotene, vitamins E and C and multivitamins alone and in combination on the prevention of cancer, CVD and eye diseases.
Christen WG et al. Design of Physicians’ Health study II – a randomized trial of beta-carotene, vitamins E and C, and multivitamins, in prevention of cancer, cardiovascular disease, and eye disease, and review of results of completed trials. Annals of Epidemiology 10(2): 125-34. Feb 2000.

PRYOR, The Biodynamics Institute, Louisiana State University, Baton Rouge 70803 USA. wpryor@LSU.edu reviews (244 references!) the evidence regarding the effects of vitamin E on heart disease, comprising basic science, animal studies, epidemiological and observation studies and 4 intervention trials.
Results: The results from in vitro, cellular and animal studies, which are impressive in quantity and quality, demonstrate that vitamin E, the most important fat-soluble antioxidant, protects animals against a variety of types of oxidative stress. The hypothesis linking vitamin E with prevention of cardiovascular disease (CVD) postulates that the oxidation of unsaturated lipids in low-density lipoprotein (LDL) particle initiates a complex sequence of events leading to the development of atherosclerotic plaque. This hypothesis is supported by many studies in vitro, in animals and in humans. There is also evidence that the ex vivo oxidizability of a person’s LDL is predictive of future heart events. These basis science and observation studies, along with the safety of vitamin E, were the impetus to clinical intervention trials. The three trials which have been reported in detail are, on balance, supportive of the proposal that supplemental vitamin E can reduce heart disease risk. The fourth trial, just reported, showed small, but not statistically significant benefits. Subgroup analyses of cohorts from the older three trials, as well as evidence from smaller trials, demonstrate that vitamin E provides protection against several medical conditions, including those indicative of atherosclerosis, such as intermittent claudication. Vitamin E supplementation is also associated with an improvement in the immune system and protection against diseases apart from CVD, such as prostate cancer. Vitamin E, at the supplemental levels used in the current trials, 100-800 IU/d, is safe, with little likelihood that increased risk exists for those individuals taking supplements. About ½ of American cardiologists take supplemental vitamin E, about the same number that take aspirin. One study suggests that aspirin plus vitamin E is more effective than aspirin alone. There are a substantial number of trials involving vitamin E in progress; however it is likely that each condition for which vitamin E provides benefit will have a unique dose-effect curve. Furthermore, since antioxidants appear to act synergistically, vitamin E may be more effective if combined with other micronutrients. Research determining the specific dose-effect curve for vitamin E for each condition in combination with other micronutrients will be long-winded and difficult to complete.
Conclusions: The scientific community should recognize that there is never a time when the science is ‘complete’ and that at some point, the weight of the scientific evidence should be judged adequate; we are very close to that time with vitamin E. In view of the very low risk of supplementation with vitamin E, and the difficulty in obtaining more than about 30 IU/day from a balanced diet, some supplementation appears prudent now.
Pryor WA. Vitamin E and heart disease: basic science to clinical intervention trials. Free Radical Biology and Medicine 28(1): 141-64. 1 Jan 2000.
Comments: Amen! Said better than I could myself.

Issue 52

GRUNDMAN, Alzheimer's Disease Cooperative study, 9500 Gilman Drive 0949, La Jolla CA 92093-0949 USA. mgrundman@ucsd.edu writes that a considerable amount of evidence suggests that oxidative stress is important in the pathogenesis of Alzheimer's disease. Of particular importance is beta-amyloid, found abundantly in the brains of Alzheimer disease patients, and is toxic in neuronal cell cultures via a mechanism involving free radicals. Vitamin E prevents the oxidative damage induced by beta-amyloid in cell culture and delays memory deficits in animal models. The authors review the literature (94 references) and conducted a placebo-controlled clinical trial to study the effects of Vitamin E in patients with moderately advanced Alzheimer's disease.
Methods: Participants in the vitamin E group were treated with 2000 IU (1342 alpha-tocopherol equivalents) vitamin E per day.
Results: Vitamin E may slow functional deterioration leading to nursing home placement. A new clinical trial is planned to examine whether vitamin E may delay or prevent a clinical diagnosis of Alzheimer's disease in elderly persons with mild cognitive impairment.
Grundman M. Vitamin E and Alzheimer disease: the basis for additional clinical trials. The American Journal of Clinical Nutrition 71(2): 630S-636S. Feb 2000.

Comments: Because of the prevalence and severity of conditions such as Alzheimer disease, research progress with supplements such as vitamin E should only be encouraged and applauded. As vitamin E already has a long history of clinical efficacy in the prevention and treatment of heart disease (see Jeffrey Bland, Issue 51), and a considerable role in the prevention of certain cancers (see Research Updates, www.positivehealth.com), I look forward to seeing the results of such further research.

LYKKESFELDT and colleagues, Department of Molecular and Cell Biology, University of California, Berkeley CA USA write that lack of reliable dietary data has hampered the ability to distinguish between effects of smoking and diet on plasma antioxidant status. The authors investigated the effect of smoking upon plasma antioxidant status by measuring vitamins C and E (alpha- and gamma-tocopherol), beta-carotene and lycopene and tested the effect of a 3-month dietary supplementation using a moderate-dose vitamin cocktail.
Methods: The authors conducted a double-blind, placebo-controlled trial to determine the effect of a vitamin cocktail on plasma antioxidants in a population of 37 smokers and 38 nonsmokers. The vitamin cocktail contained 272 mg vitamin C, 31 mg all-rac-alpha-tocopheryl acetate and 400 microg folic acid. The subjects were selected for having a low intake of fruit and vegetables.
Results: Only vitamin C was significantly depleted by smoking. Following the 3 month supplementation period, vitamin C was efficiently repleted in smokers. Plasma alpha-tocopherol and the ratio of alpha- to gamma-tocopherol increased significantly in both supplemented groups.
Conclusions: These data suggest that previous reports of lower concentrations of plasma vitamin E and carotenoids in smokers than in nonsmokers may primarily have been caused by differences in dietary habits between study groups. Plasma vitamin C was depleted by smoking and repleted by moderate supplementation.
Lykkesfeldt J et al. Ascorbate is depleted by smoking and repleted by moderate supplementation: a study in male smokers and nonsmokers with matched dietary antioxidant intakes. The American Journal of Clinical Nutrition 71(2): 530-6. Feb 2000.

Issue 51

Issue 50

HEMILA and colleagues, Department of Public Health, University of Helsinki, Finland studied the association of vitamin C intake and risk of tuberculosis.
Methods: The authors analysed 167 incident cases of tuberculosis during a median follow-up time of 6.7 years within a clinical trial cohort of 26,975 Finnish men for whom baseline dietary data were on record.
Results: The study demonstrated a highly statistically significant inverse association between calculated vitamin C intake and tuberculosis incidence; however following adjustment for non-dietary factors, the association weakened to nonsignificant. Additionally, risk of tuberculosis decreased with increasing intake of fruits, vegetables and berries independent of vitamin C intake. Individuals with dietary vitamin C intake >90 mg per day and who consumed more than the average amount of fruits, vegetables, and berries had a significantly lower risk of tuberculosis (adjusted relative risk (RR) = 0.40).
Discussion: Associations between dietary vitamin C intake and occurrence of various diseases without proper control of confounding factors have often been interpreted as causal. The findings of this study indicate that such associations can be confounded even by other dietary components.
Conclusions: Lower tuberculosis incidence in people who consume more fruits, vegetables and berries poor in vitamin C suggests that other compounds apart from vitamin C in such a diet may reduce the risk of tuberculosis.
Hemila H et al. Vitamin C and other compounds in vitamin C rich food in relation to risk of tuberculosis in male smokers. American Journal of Epidemiology 150(6): 632-41. 15 Sep 1999.

COWAN and colleagues, School of Dentistry, The Queen’s University of Belfast, Royal Victoria Hospital, Northern Ireland write that although the antioxidant status of a person is thought to be important in the development of potentially malignant oral lesions (PMDL) and oral squamous cell carcinoma (OSCC), little information regarding mucosal antioxidant status is known in the UK. The relationship between smoking and mucosal antioxidant status has not yet been established. The authors studied 60 people, in order to establish data regarding these questions.
Methods: 60 individuals participated in this study, all of whom had an oral mucosal biopsy and simultaneous venous blood sampling. Antioxidant levels were measured using high performance liquid chromatography (hplc).
Results: Compared with non-smokers (n=41), smokers (n=19) had significantly lower levels of plasma beta-carotene and significantly lower levels of tissue alpha-carotene. Tissue alpha-carotene correlated with plasma levels; however this was not the case with alpha-tocopherol (vitamin E), retinol (vitamin A), lycopene or beta-carotene.
Conclusions: These results are the first data regarding oral mucosal antioxidant levels and provide baseline data from which to study patients with potentially malignant oral lesions and oral squamous cell carcinoma.
Cowan CG et al. Antioxidant status of oral mucosal tissue and plasma levels in smokers and non-smokers. Journal of Oral Pathology and Medicine 28(8): 360-3. Sep 1999.

WEBER, F Hoffmann-La Roche Ltd, Vitamins and Fine Chemicals Division, Human Nutrition and Health, Basel, Switzerland reviews (41 references) the main role vitamins are believed to play in the prevention of osteoporosis.
Results and Discussion: Vitamin D improves bone strength mainly by increasing intestinal calcium absorption and reabsorption of calcium by the kidney. Research in humans has demonstrated that vitamin D can improve bone status as measured by bone density. Vitamin C is considered to an essential cofactor of collagen formation and epidemiological studies demonstrate a positive association between vitamin C intake and bone density; however intervention studies regarding the effect of vitamin C upon bone status have not been conducted. Vitamin B6 may function as a cofactor to build up cross-links; however, there is little evidence in humans to support this. Vitamin K is required for the activity of several coagulation factors. Recent research also suggests a role for vitamin K in bone metabolism, in that vitamin K mediates the carboxylation of glutamyl residues on several bone proteins, including osteocalcin. Results from epidemiological studies and intervention trials consistently suggest that vitamin K may improve bone health.
Weber P. The role of vitamins in the prevention of osteoporosis – a brief status report. International Journal for Vitamin and Nutrition Research 69(3): 1947. May 1999.

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Issue 48

Issue 47

FOUCARD and MALMHEDEN-YMAN, Department of Paediatrics, University Hospital, Uppsala, Sweden write that all physicians were asked to report fatal and life-threatening reactions caused by food, following a fatal case of soy anaphylaxis which occurred in Sweden in 1992. The authors report the results of the first 3 years of the study, including results from another ongoing study regarding deaths from asthma during the same period.
Results: From 1993-6, 61 cases of severe reactions to food were reported, 5 of them fatal. Peanut, soy and tree nuts appeared to have caused 45 of the 61 reactions and 4 of them were fatal. Including 2 cases which occurred less than a year prior to the start of their study, the authors are aware of 2 deaths caused by peanuts and 4 deaths caused by soy. All 4 youngsters who died from soy anaphylaxis with asthma were severely allergic to peanuts but had no previously known allergy to soy. In the majority of cases, there was a rather symptom-free period for 30-90 minutes between early mild symptoms and severe and rapidly deteriorating asthma.
Conclusions: Soy has probably been underestimated as a cause of food anaphylaxis. Those at risk appear to be young people with asthma and peanut allergy so severe that they notice symptoms after indirect contact.
Foucard T et al. A study on severe food reactions in Sweden – is soy protein an underestimated case of food anaphylaxis? Allergy 54(3): 261-5. Mar 1999.

Issue 46

KIDD USA writes that dementias and other severe cognitive dysfunction states pose a daunting challenge to existing medical management strategies and that an early intervention, integrative approach would seem to be appropriate. Nutrition and botanical therapies have proven degrees of efficacy and provide favourable benefit-to-risk profiles.
Results and Discussion: The author reviews (103 references) 5 nutritional therapies: phosphatidylserine (PS), acetyl-1-carnitine (ALC), vinpocetine, Ginkgo biloba extract (GbE) and Bacopa monniera (Bacopa). PS is a phospholipid enriched in the brain and which has been validated with double-blind trials for improvements of memory, learning, concentration, word recall and mood in middle-aged and elderly people suffering from dementia or age-related cognitive decline. PS has an excellent benefit-to-risk profile. ALC is an energiser and metabolic cofactor also benefiting various cognitive functions in the middle-aged and elderly, with a slightly less favourable benefit-to-risk profile. Vinpocetine, found in the lesser periwinkle Vinca minor is an excellent vasodilator and cerebral metabolic enhancer which has proven benefits for vascular-based cognitive dysfunction. The best preparations of GbE offer limited benefits for vascular insufficiencies and even more limited benefits for Alzheimer’s; "commodity" GbE products offer little, if any benefits at all. GbE and probably also vinpocetine are incompatible with blood-thinning drugs. Bacopa is an Ayurvedic botanical with apparent anti-anxiety, anti-fatigue and memory-strengthening effects.
Conclusions: The 5 nutritional/botanical substances contribute to a personalised approach for restoring cognitive function, perhaps eventually in conjunction with appropriate application of growth factors.
Kidd PM A review of nutrients and botanicals in the integrative management of cognitive dysfunction. Alternative Medicine Review 4(3): 144-61 Jun 1999.

BANERJEE and colleagues, Department of Occupational Health, All India Institute of Hygiene & Public Health, Calcutta India write that free radicals and lipid peroxidation play a significant role in the causation of human disease such as cancer, atherosclerosis, rheumatoid, arthritis, cataract by oxidative damage and functional degeneration of the tissues. The authors conducted a study to study the effect of cigarette smoking upon Vitamin C, glutathione and lipid peroxidation status.
Results: Vitamin C and other antioxidants such as glutathione protect the lipids of lipoproteins and other biomembranes against peroxidative damage. Cigarette smoking affected vitamin C’s and glutathione’s antioxidant protective action. The group of adult male smokers in this study were found to have lowered vitamin C and glutathione levels and increased lipid-peroxide levels in their blood.
Conclusions: The increased pathogenicity of the smoking may also be due to indirect biochemical effect of enhanced oxidative stress by increased lipid-peroxidation and lowered vitamin C and other antioxidants at tissue level.
Banerjee KK et al. Influence of cigarette smoking on Vitamin C, glutathione and lipid peroxidation status. Indian Journal of Public Health 42(1): 20-3. Jan-Mar 1998.

GOLDFARB, Department of Exercise and Sport Science, University of North Carolina-Greensboro 27402-6169 USA write that several mechanisms have been proposed to explain the aetiology of exercise-induced muscle damage. The authors review (74 references)the field of muscle damage.
Results and Discussion: Free radical mediated processes appear to be an important component of the inflammatory mediated response and have been demonstrated to be a contributing factor in the loss of calcium homeostasis within the cell. Therefore, intervention of free-radical mediated processes is one of the proposed treatments for preventing or reducing the extent of this damage. Antioxidants work by quenching free radicals; the traditional dietary antioxidants most commonly studied are vitamins C, E and beta-carotene. Other nutritional agents, such as isoflavonoids and other phytochemicals have been proposed to contain antioxidant properties. The author briefly reviews these agents and their putative roles, proven or proposed, in the prevention of oxidative stress and muscle damage.
Goldfarb AH. Nutritional antioxidants as therapeutic and preventive modalities in exercise-induced muscle damage. Canadian Journal of Applied Physiology 24(3): 249-66. Jun 1999.

HEMILA, Department of Public Health, University of Helsinki, Finland writes that placebo-controlled trials have demonstrated that vitamin C supplementation decreases the duration and severity of common cold infections, but that the magnitude of the benefit has varied substantially, hampering conclusions regarding the clinical significance of vitamin C. The authors reviews the literature (54 references) on this subject.
Methods: The author analysed the data of 23 studies with regular vitamin C supplementation of > 1 g/day to discover factors which could account for part of the variation in the results.
Results: On average vitamin C produces greater benefit for children compared with adults. The dose affects the magnitude of the benefit, with a dose of > or = 2 g/day producing greater benefit compared with 1 g/day. In 5 studies in adults given 1 g/day vitamin C, the median decrease in cold duration was only 6%, whereas in 2 studies with children given 2 g/day, the median decrease was 4 times greater, 26%.
Conclusions: The trials analysed above used regular vitamin C supplementation, but it is possible that therapeutic supplementation started early at the onset of the cold episode could have produced comparable benefits. Since few trials have studied the effects of therapeutic supplementation and their results have been variable, further therapeutic trials are needed to definitively establish the beneficial role of vitamin C in the treatment of colds.
Hemila H. Vitamin C supplementation and common cold symptoms: factors affecting the magnitude of the benefit . Medical Hypotheses 52(2): 171-8. Feb 1999.

Issue 45

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