High Dietary Intake Of Vitamin Research Articles

The UK food data-base for vitamin K and why we need it

The need to make accurate assessments of dietary intakes vitamin K has been driven by recent evidence that vitamin K-dependant (Gla) proteins are widely present in the body and have other important physiological functions other than coagulation. Two of these proteins, osteocalcin and matrix Gla protein (MGP), are thought to have a role in maintaining skeletal integrity while MGP acts as an inhibitor of calcification in arteries and cartilage. An added impetus has been the development of functional markers that enable vitamin K status to be assessed from a tissue-specific perspective and evidence that bone Gla-proteins require higher dietary intakes of vitamin K for optimal carboxylation than do hepatic coagulation Gla-proteins. The UK food data-base for vitamin K began on an ad-hoc basis to identify the major individual food contributors but recently has been expanded to include values based on recipe calculations and food similarities. To date the data-base is restricted to the plant form phylloqinone, the major food source of vitamin K. The food items used to calculate values for composite foods have all been analyzed by a validated HPLC procedure, some 170 by our London laboratory. Currently about 2000 food items have been assigned a provisional phylloquinone content. Although this food data-base has enabled the first assessments of dietary intakes of phylloquinone in UK populations, many assigned values are provisional and need to be validated by direct analysis. Further work is needed to assess issues such as inter-sample variability, storage losses and the content of bacterial menaquinones.

Effect of high dietary intake of vitamin C on non-specific immune response of gilthead seabream (Sparus aurata L.)

To determine the effect of a high level of dietary intake of ascorbic acid (vitamin C) on the non-specific immune response of gilthead seabream (Sparus aurata L.), specimens were fed diets containing 500mg kg−1(control) and 3,000mg kg−1ascorbic acid for 2, 4, 6, 8 or 10 weeks. Growth, serum level of vitamin C, natural haemolytic complement activity and head-kidney leucocyte migratory, respiratory burst and phagocytic activities were studied at each one of the assayed times. A positive relationship between vitamin C intake and serum ascorbic acid was observed, the enhancement being evident after 2 weeks of administration and maintained until 10 weeks. Specimens fed a vitamin C supplemented diet showed a slightly higher (but no statistically significant) specific growth rate than fish fed the control diet. The non-specific immune response parameters assayed were enhanced by the dietary intake of vitamin C although, each one peaked at a different time: phagocytic activity after 2 weeks of administration, natural haemolytic complement activity after 6 weeks, respiratory burst after 8 weeks. However, leucocyte migration was not affected. The results indicated that the serum ascorbate concentration of specimens fed a high level of vitamin C reach a plateau. The non-specific immune response parameters assayed increased as a consequence of a high vitamin C supply, although the increase was not maintained but returned to the initial levels. This suggests that the immune response accomodates to the new high vitamin C plasma availability after a transient enhancement.

High dietary intake of vitamin K was associated with decreased warfarin sensitivity*

High dietary intake of vitamin K was associated with decreased warfarin sensitivity*

High Dietary Intake of Vitamin E Causes Lowered Total Plasma Oxidation In Hypercholesterolemic Rats

Oxidative stress appears to play a key role in the development of atherosclerosis. Patients with cardio-vascular diseases have increased plasma lipid peroxides. Low-density lipoprotein cholesterol (LDL) in plasma must undergo oxidative modification before giving rise to foam cells, one of the earliest stages in the development of atherosclerosis. Epidemiological evidence suggests that high dietary intake of vitamin E may protect plasma from oxidation, thereby reducing the risk for heart disease. To test this hypothesis, five groups of hypercholesterolemic rats were fed diets containing various amounts of vitamin E, ranging from zero milligrams (deficient diet) to 2400 milligrams (high level supplementation). Total plasma oxidation was determined by measuring the formation of malondialdehyde (a lipid peroxidation product) at baseline and after inducing iron-catalyzed lipid peroxidation. The results are summarized below: Vitamin E Malondialdehyde formation (mg/kg diet) (nmol/ml plasma) Baseline Oxidation Group I 60 3.636 5.395 Group II 0 6.673 23.197 Group III 300 8.252 22.358 Group IV 600 7.532 15.864 Group V 2400 8.392 13.896 (Group I - no cholesterol control diet) KEY FINDINGS: Upon iron-induced oxidation, MDA formation from baseline values was highest in the animals that were vitamin E deficient (group II). The formation of MDA decreased steadily from baseline values as vitamin E levels went higher. Decreased MDA formation in group I could be due to the low cholesterol substrate levels available for oxidation. It appears that high levels of vitamin E supplementation may exert a protective effect by decreasing lipid peroxidation, thereby reducing the oxidative stress.

Humoral immune response impairment following excess vitamin E nutrition in the chick and turkey

The effect of high dietary intakes of vitamin E on antibody production was investigated in chicks and turkeys. Chicks were fed four diets with 0, 10, 30, and 150 mg/kg added vitamin E and turkeys were fed three diets with 0, 50, and 150 mg/kg added vitamin E. Antibodies produced in response to naturally occurring Escherichia coli and to Newcastle disease virus and turkey pox vaccines were determined. In chicks, antibody production in response to E. coli and Newcastle disease was affected by vitamin E nutrition: significantly higher responses were measured in chicks that received 0 and 10 mg/kg added vitamin E, whereas in chicks receiving 30 and 150 mg/kg, antibody production was significantly lower. In turkeys, concentrations of circulating antibodies to Newcastle disease virus and to turkey pox were also influenced by dietary vitamin E: antibody titers to Newcastle disease and turkey pox vaccines were highest in groups receiving 0 mg/kg added vitamin E, whereas titer in groups receiving 150 mg/kg were significantly lower. Responses of groups receiving 50 mg/kg added vitamin E were slightly lower than groups receiving 0 mg/kg, though not significantly so in most cases. These results indicate that humoral immune responses are directly effected by vitamin E, and that excessive vitamin E intake has a detrimental effect on antibody production in chickens and turkeys.

High Dietary Intake of Vitamin E Causes Decreased Incidence of Early Atherosclerotic Lesions in Rats

LEARNING OUTCOME: To examine the role of high level vitamin E supplementation on the formation of atherosclerotic lesions. Elevated levels of oxidized low-density lipoprotein (LDL) is a major risk factor for atherosclerosis. Epidemiological evidence suggests that high dietary intake of vitamin E may decrease the risk for atherosclerotic vascular disease by protecting LDL from oxidation. To test this hypothesis, five groups of 12 rats were fed diets containing varying amounts of cholesterol and vitamin E. Plasma lipids [total cholesterol, high-density lipoprotein (HDL) and triglyceride (TG)] and the extent of aortic lesions were examined after 5 months of consumption of the diet. The results are summarized in the table below: Group 1 Group 2 Group 3 Group 4 Group 5 Vitamin E 60 mg 60 mg 300 mg 600 mg 2400 mg Total Chol. (mg/dl) 152 1016 1006 1227 1232 LDL(mg/ml) 0.9 1.1 1.5 1.5 1.6 HDL (mg/dl) 124 48 50 69 109 TG (mg/dl) 213 408 329 347 448 Group 1: No Cholesterol/Cholic acid Group 2-5: Cholesterol - 1.0%, Cholic acid 0.3% of the basal diet. Vitamin E: Given as tocopheryl acetate, mg/kg of diet. Key research findings are: Hypercholesterolemia and lower HDL cholesterol levels in the plasma were found to cause early atherosclerotic lesions in twice the number of rats (groups 4 and 5) as compared to rats (group 1) fed no cholesterol. The incidence of atherosclerotic lesions in the groups that received 600 & 2400 mg of vitamin E was 50% lower than the group that received 300 mg of vitamin E. It appears that high levels of vitamin E supplementation and HDL exert a protective effect which results in a decrease in atherosclerotic lesion formation.

Dietary antioxidants and Parkinson disease. The Rotterdam Study.

To investigate whether high dietary intake of antioxidants decreases the risk of Parkinson disease (PD). The community-based Rotterdam Study, the Netherlands. The cross-sectional study formed part of a large community-based study in which all participants were individually screened for parkinsonism and were administered a semiquantitative food frequency questionnaire. The study population consisted of 5342 independently living individuals without dementia between 55 and 95 years of age, including 31 participants with PD (Hoehn-Yahr stages 1-3). The odds ratio for PD was 0.5 (95% confidence interval [CI], 0.2-0.9) per 10-mg daily dietary vitamin E intake, 0.6 (95% CI, 0.3-1.3) per 1-mg beta carotene intake, 0.9 (95% CI, 0.4-1.9) per 100-mg vitamin C intake, and 0.9 (95% CI, 0.7-1.2) per 10-mg flavonoids intake, all adjusted for age, sex, smoking habits, and energy intake. The association with vitamin E intake was dose dependent (P for trend = .03). To assess whether the association was different in participants with more advanced disease, we excluded those with PD who had a Hoehn-Yahr stage of 2.5 or 3. This did not fundamentally alter the results. Our data suggest that a high intake of dietary vitamin E may protect against the occurrence of PD.

Increased risk for hip fracture and low bone mineral density with high dietary intake of vitamin A

Increased risk for hip fracture and low bone mineral density with high dietary intake of vitamin A

High Dietary Intakes of Vitamin E and Cellular Immune Functions in Rats

High dietary intakes (100-2500 mg/kg diet) of vitamin E (dl-alpha-tocopheryl acetate) modified the functions of splenic lymphocytes and alveolar macrophages (AM). The numbers of splenocytes and AM obtained from male F344 rats fed high vitamin E diets significantly increased at 10 d after the onset of the experiment. Splenic lymphocytes' responses to concanavalin A and natural killer cell activity also increased with increasing contents of vitamin E in the diets. Furthermore, the ability of AM to phagocytose opsonized sheep red blood cells increased with increasing contents of vitamin E in diets and showed a fivefold increase in rats fed the diet with the highest vitamin E content (2500 mg/kg diet) compared with rats in the control group. The lavage fluid of lungs from rats fed a high vitamin E diet (500 mg/kg diet) increased phagocytic activity of AM from rats fed a basal diet; it also induced a 72% increase in activity compared to that in control rats. The phagocytic activity of AM was not enhanced when the large molecules (MW greater than 10,000) were removed by ultrafiltration from the lavage fluid of lungs of rats fed the high vitamin E diet (500 mg/kg diet). These data suggest that there is macrophage-activating factor-like material in the lavage fluid of lungs of rats fed high vitamin E diets and that high vitamin E diets may activate not only splenic lymphocytes but also AM.

Vitamin A and lung cancer: a perspective.

Sixteen studies of the relationship between lung cancer and vitamin A in humans are critically reviewed: eight dietary studies and eight serum studies. Of the eight dietary studies, only five had case samples large enough to warrant meaningful statistical analysis. Three dietary studies reported a negative association between vitamin A intake and lung cancer after proper adjustment for cigarette smoking and socioeconomic effects; the results suggested that daily consumption of green-yellow vegetables reduces the risk of lung cancer in all categories of smokers. The reduction in risk was found to be greatest in persons in the higher socioeconomic strata. Four dietary studies suggested that high intake of dietary vitamin A has a protective effect against the development of squamous and small cell carcinoma of the lung in smokers. Three studies revealed a lower risk of lung cancer among persons who consume carrots and milk daily. None of the eight serum studies reviewed had large enough samples of lung cancer cases to allow for meaningful statistical analysis. However, four of the serum studies reported significantly lower serum vitamin A levels in lung cancer cases than in controls. Analysis of the above studies demonstrated shortcomings in each. Future studies should include all of the following factors: more complete vitamin A indices, examination of the histological type of lung cancer, a large enough pool of both male and female patients for statistical analysis, and proper adjustment for the effects of age, sex, smoking, and socioeconomic status.