Research Database –
International Updates

Diet and Health

Issue 34

RIORDAN and colleagues, Addenbrookes Hospital, Cambridge reviewed the available literature (41 references) regarding associations between onset of Crohn’s disease and intakes of sugars or sugar-containing foods.
Methods: The authors reviewed all publications from refereed journals which reported intakes of sugars and sugar-containing foods in the context of Crohn’s disease onset or treatment.
Results: The evidence suggesting that there is a relationship between sugars and the onset of Crohn’s disease was inconsistent and subject to important methodological limitations. There was a clear lack of distinction between the reporting of current, as compared to retrospective intakes.
Conclusions: There appears to be no clinical advantage to the use of reduced sugar diets in Crohn’s disease treatment.
Riordan AM et al. A review of associations between Crohn’s disease and consumption of sugars. Eur J Clin Nutr 52(4): 229-38 Apr 1998.

Comments: Because there are methodological limitations in the studies does not necessarily lead to the conclusion that there is no clinical advantage to use of reduced sugar in diets in patients with Crohn’s disease. The overconsumption of sugar is being implicated in a major fashion in many health problems, including obesity, heart disease, cancer, diabetes. Many nutritional practitioners report favourable outcomes with patients whose diets are altered to a more wholefood-based and especially without excess simple sugars. I have not reviewed the papers found by the authors’ search of the literature, but my hunch is that improving the diets of patients with Crohn’s disease must have positive results.

HOLLOSZY, Department of Medicine, Washington University School of Medicine, St Louis, MO 63110, USA. writes that food restriction increases maximum life span in rodents, but that male rats that exercise in voluntary running wheels do not have an increased maximal longevity despite a relative caloric deficit. On the contrary, sedentary rats that are food restricted so that they have the same caloric deficit have an extension of maximal longevity.
Methods: The author proposes that exercise-induced oxidative stress could prevent a maximum life span-extending effect of a caloric deficit and conducted a study to determine if antioxidants would enable a maximal longevity-extending effect of exercise to manifest in male rats.
Results: The antioxidant diet did not affect longevity in the runners or the sedentary controls. Wheel running modestly increased average longevity but had no effect upon maximal life span.
Conclusions: The results that antioxidants did not affect longevity of the wheel runners supports the interpretation that the caloric deficit induced by exercise in male rats does not have a life-extending effect that is countered by oxidative tissue damage.
Holloszy JO. Longevity of exercising male rats: effect of an antioxidant supplemented diet. Mech Ageing Dev 100(3): 211-9 Feb 16 1998.

SIU and colleagues, Department of Optometry and Radiography, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong studied how melatonin and vitamin E antioxidants protect cells from the damaging effects of free radicals.
Methods: The authors compared the effect of melatonin and vitamin E against lipid peroxidation (LOP) in rat retinal homogenates, in order to characterise the antioxidative efficacy of melatonin in the retina, a tissue highly sensitive to oxidative damage. Malondialdehyde (MDA) was used to provide an index of cell damage in vitro.
Results: Levels of lipid peroxidation products were significantly reduced in a dose-response manner by all concentrations of vitamin E and melatonin, in concentrations of both 2.0 or 4.0 mM, significantly reduced LOP. Vitamin E treatment always yielded a lower level of LPO products than did the same concentration of melatonin. The concentrations of each agent required to inhibit 50% of the lipid damage (IC50) were 0.69 mM and 4.98 mM for vitamin E and melatonin, respectively.
Conclusions: Both vitamin E and melatonin protect the retina against LPO in a dose-dependent manner. Although the IC50 value for melatonin is approximately 7.2 times higher than that of vitamin E, the pharmacological and physiological role of melatonin in the treatment and/or prevention of retinal diseases in vivo merits further investigation.
Siu AW et al. The efficacy of vitamin E and melatonin as antioxidants against lipid peroxidation in rat retinal homogenates. J Pineal Res 24(4): 239-44. May 1998.

KAWAI and colleagues, Department of Neuroscience, Institute of Molecular and Cellular Medicine, Okayama University Medical School, Japan. mokawai@cc.okayama-u.ac.jp. studied, in rats, the effects of Manda, a yeast fermented product of several fruits and black sugar, upon lipid peroxidation, as a model of ageing.
Methods: Senescent rats were provided with a diet of 50g/100g Manda for 8 days, supplemented on day 8 with an intragastric administration of Manda (6 g/kg body weight) twice daily. The authors measured the hydroxyl radical scavenging activity by electron spin resonance spectrometry.
Results: Manda had an additive inhibitory effect upon lipid peroxidation compared with control adult rats not given Manda. Incubation of homogenates with Manda significantly inhibited the increase in lipid peroxides (malondialdehydes and 4-hydroxyalkenals) levels in aged rats caused by auto-oxidation. Additionally, oral administration of Manda
significantly suppressed the age-related increase in lipid peroxidation in the hippocampus and striatum, although no corresponding change was observed in the cerebral cortex. Although Manda contains trace level of alpha-tocopherol, the level of alpha-tocopherol in Manda did not correlate with its antioxidant effect.
Conclusions: These data suggest that Manda protects against age-dependent oxidative neuronal damage caused by oxidative stress and that this protective effect may be due, in part, to its free radical scavenging activity.
Kawai M et al. Manda, a fermented natural food, suppressed lipid peroxidation in the senescent rat brain. Neurochem Res 23(4): 455-61. Apr 1998.

Issue 31

CRAIG, Andrews University, Berrien Springs, Michigan USA writes that consuming a diet rich in plant foods containing phytochemicals and nonnutritive plant substances will confer health-protective benefits. Phenolic compounds, terpenoids, pigments and natural antioxidants, associated with protection from and/or treatment of chronic diseases including heart disease, cancer, diabetes and hypertension are found in nuts, whole grains, fruits and vegetables. Foods and herbs with the highest anticancer activity are garlic, soybeans, cabbage, ginger, licorice and umbelliferous vegetables. Citrus fruits contain a variety of active phytochemicals, in addition to providing a good supply of vitamin C, folic acid, potassium and pectin.. Phytochemicals found in grains reduce the risk of cardiovascular disease and cancer.
Craig WJ. Phytochemicals: guardians of our health. J Am Diet Assoc. 97 (10 Suppl 2): S199-204. Oct 1997.

COMMENTS: For a detailed and elucidating account of phytochemicals, please refer to the page 5 of Positive Health, where we publish an extract from Maryon Stewart’s new book The Phyto Factor, Vermillion Press 1998.

MACRIDES and colleagues, Department of Medical Laboratory Science, RMIT-University, Melbourne, Victoria, Australia compared the hydroxyl radical (OH) quenching abilities of the following antioxidant compounds: 1) 5 beta-scymnol, the hepatoprotective shark bile sterol and its mono- and di-sulfate esters 2) 3 marketed pycnogenol preparations (syn: proanthocyanidin – natural plant-derived polyphenolic bioflavonoids) extracted from pine tree (Pinus maritima) bark and grape (Vitis vinifera) seeds 3) 2 known hydroxyl radical scavengers, dimethyl sulfoxide (DMSO) and mannitol and 4) the peroxyl radical scavenger Trolox, the alpha-tocopherol analogue. RESULTS: 5 beta-scymnol was a more potent OH quencher than DMSO, mannitol and Trolox, and significantly more potent than the pycnogenol preparations. Increasing the sulfation of 5 beta-scymnol progressively reduced its free radical scavenging activity, hence attributing its potent OH quenching properties to its novel tri-alcohol-substituted aliphatic side chain. CONCLUSIONS: The favourable interaction of these shark bile steroids with reactive oxygen species in an aqueous environment makes them attractive candidates for their evaluation as protective agents against illnesses associated with oxidative stress.
Macrides TA et al. A comparison of the hydroxyl radical scavenging properties of the shark bile steroid 5 beta-scymnol and plant pycnogenols. Biochem Mol Biol Int. 42 (6): 1249-60. Sep 1997.

BAUM and colleagues, Department of Psychiatry and Behavioral Sciences, University of Miami, School of Medicine, Florida 33136 USA studied the independent contribution of immune and nutritional factors upon survival in HIV. METHODS: The authors looked at CD4 cell count, anti-retroviral treatment, blood plasma levels of vitamins A, E, B6, B12 and minerals selenium and zinc in relation to relative risk for HIV-related mortality. Immune and nutritional parameters were evaluated at 6 month intervals in 125 HIV-positive drug-using men and women in Miami Florida over a period of 3.5 years. RESULTS: 21 HIV-positive people participants died of HIV-related causes during the study. The following nutritional parameters, but not zidovudine treatment, were each shown to be associated with HIV-related mortality, independent of CD4 cell counts <200/mm3 at baseline and over time as follows: subclinical malnutrition, relative risk (RR) = 4.01 vitamin A deficiency RR = 3.23 vitamin B12 deficiency RR = 8.33 zinc deficiency RR = 2.29 selenium deficiency RR = 19.19. When all factors affecting survival, including CD4 counts at baseline and over time and nutritional deficiencies were jointly considered, only CD4 counts over time (RR = 0.69) and selenium deficiency (RR = 10.8) were significantly associated with mortality. CONCLUSIONS: These results demonstrate that selenium deficiency is an independent predictor of survival for those infected with HIV.
Baum MK et al. High risk of HIV-related mortality is associated with selenium deficiency. J Acquir Immune Defic Syndr Hum Retrovirol 15(5): 370-4. Aug 15 1997.

SANTOS and colleagues, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston MA 02111 USA write that providing healthy elderly people with dietary supplements of beta-carotene has been considered a method to enhance their immune response. The authors studied the effects of beta-carotene upon immunity. METHODS: The authors conducted a randomised, double-blind, placebo-controlled longitudinal comparison of healthy elderly women to study the short-term effects of beta-carotene (90mg/day) upon immunity for 3 weeks (Study 1). The authors conducted a second study, a randomised, double-blind, placebo-controlled longitudinal comparison of men enrolled in the Physicians’ Health Study (Study 2) to assess the long-term effect of beta-carotene (50 mg every other day for 10-12 years). RESULTS: The participants in both studies who took the beta-carotene supplements showed significantly greater concentrations of plasma beta-carotene than those in the placebo group. In neither the short-term or long-term studies, the pre- to post-intervention change in delayed-type hypersensitivity skin test responses between the beta-carotene and placebo groups was not significantly different. There were no significant differences seen upon in vitro lymphocyte proliferation, production of interleukin-2 or prostaglandin E2 in either the short- or long-term supplementation groups. There were no differences in profiles of lymphocyte subsets (total T cells (CD3+), T-helper cells (CD4+), T cytotoxic-suppressor cells (CD8+) and B cells (CD19+), nor differences in percentages of CD16+ natural killer cells or activated lymphocytes (cells expressing interleukin 2 transferrin receptor) in the long-term supplemented group. CONCLUSIONS: The results from these two trials showed that supplementation with beta-carotene did not enhance or suppress T cell-mediated immunity in healthy elderly people.
Santos MS et al. Short- and long-term beta-carotene supplementation do not influence T cell-mediated immunity in healthy elderly persons. Am J Clin Nutr 66 (4): 917-24. Oct 1997.

COMMENTS: What is now required would be parallel short and long-term studies investigating the effects of beta-carotene upon immunity in elderly people who were not healthy. One would imagine that an effect could be seen where deficiencies exist.

Issue 25

FOSTER, Department of Geography, University of Victoria, British Columbia Canada writes that cancer and heart disease display spatial patterns suggesting the possible involvement of calcium and selenium deficiencies and mercury excess in their aetiologies. As a result, longevity tends to be most common in regions where the environment is calcium- and selenium-enriched and contains only low levels of mercury. The author cites examples from West Africa, China, England and the USA.
Foster HD. Landscapes of longevity: the calcium-selenium-mercury connection in cancer and heart disease. Med Hypotheses. 48(4): 355-60. Apr 1997.

KEENE and HOPE, University of Oxford, Department of Psychiatry, Warneford Hospital, Oxford UK write that up to one third of dementia sufferers eat more food at some stage during their dementia compared to before the onset of their illness. Additionally, over half of people with dementia are reported by their carers to show a marked change in food choice, especially an increased preference for sweet food. METHODS: The macronutrient content of foods chosen and ratio of sweet to savoury foods were experimentally studied using a standardised mixed meal. 3 subject groups were studied: 17 people with dementia reported by their carers to overeat and who ate excessively under experimental conditions; 14 people with dementia who ate a normal amount; and normal, non-demented controls (18 under 50 years old and 14 over 50 years old). RESULTS: The normal elderly people chose a lower proportion of high-protein food than the young. The proportion of protein eaten was lower in people with dementia than in age-matched controls and even lower in the overeating dementia group. The proportion of sweet food eaten was higher in people with dementia and even higher in people with dementia who overate. A number of mechanisms which could explain these results are discussed.
Keene JM and Hope T. Hyperphagia in dementia: 2. Food choices and their macronutrient contents in hyperphagia, dementia and ageing. Appetite 28(2): 167-75. Apr 1997.

MANNISTO and colleagues, National Public Health Institute, Department of Nutrition, Helsinki Finland studied the associations of alcohol beverage drinking with macronutrients, antioxidants and body mass index. METHODS: 985 women and 863 men aged 25-64 years of age were drawn from the population register in the four monitoring areas of the 1992 Finmonica cardiovascular risk factor survey in Finland. The participants were mailed a questionnaire including questions relating to socioeconomic factors, physical activity, smoking and alcohol consumption. Diet was assessed using a 3-day food record. RESULTS: Dietary differences between abstainers and alcohol consumers were more significant than between consumers of different alcoholic beverages. Fat intake as a percentage of energy intake was higher and carbohydrate intake lower in drinkers compared to abstainers. Wine drinkers, however, had the highest vitamin C intake and female wine drinkers also had the highest carotenoid intake. With the exception of those who mainly preferred spirits, alcohol energy was not added to the diet but seemed to substitute food items both for men and women. Male drinkers were leaner than abstainers, despite the similar total daily energy intakes, daily energy expenditure and physical activity index. For women, the proportion of underreporters of energy intake increased with increasing alcohol consumption, and the association between alcohol and body mass index was similar to men after the exclusion of underreporters. CONCLUSIONS: Alcohol consumers were leaner than abstainers and wine drinkers had more antioxidants in their diet.
Mannisto S et al. Alcohol beverage drinking, diet and body mass index in a cross-sectional survey. Eur J Clin Nutr 51(5): 326-32. May 1997.

KARJALAINEN and colleagues, Department of Pediatric Dentistry, University of Turku Finland, as part of the long-term prospective randomised dietary intervention at age 7 months to prevent exposure of children to known atherosclerosis risk factors (the STRIP baby project), report the oral effects of the dietary intervention in the children and their parents when the children had reached 3 years of age. METHODS: Every fifth family of the main study was invited to this substudy (n = 179) and 148 were studied. The families studied were representative of the intervention and control groups and both genders with regard to intake of saturated fatty acids, dietary polyunsaturated fatty acid to saturated fatty acid (PUFA/SAFA) ratio and serum cholesterol and HDL cholesterol concentrations. RESULTS: There was no difference in sucrose consumption between the intervention and control groups; however intervention children received relatively more energy from carbohydrates than control children, used less fat and had a higher PUFA/SAFA ratio in their diet. 93% of the 3-year old children were caries free; dental decay was similar in the intervention and control children. Control children brushed their teeth unassisted more often than intervention children. Intervention fathers received more energy from carbohydrates, intervention mothers used less fat and had a higher PUFA/SAFA ratio in the diet than control fathers and mothers, respectively. Dental and periodontal health of intervention and control parents also showed no differences. CONCLUSIONS: A 29-month period of a low-saturated-fat, low-cholesterol but high-carbohydrate diet as advocated in the STRIP baby trial had no harmful effects upon the oral health of the children or their parents.
Karjalainen S et al. Oral health of 3-year-old children and their parents after 29 months of child-focused antiatherosclerotic dietary intervention in a prospective randomized trial. Caries Res 31(3): 180-5. 1997.