High Ascorbic Acid Intake Research Articles

Enhancers of Iron Absorption: Ascorbic Acid and other Organic Acids

Ascorbic acid (AA), with its reducing and chelating properties, is the most efficient enhancer of non-heme iron absorption when its stability in the food vehicle is ensured. The number of studies investigating the effect of AA on ferrous sulfate absorption far outweighs that of other iron fortificants. The promotion of iron absorption in the presence of AA is more pronounced in meals containing inhibitors of iron absorption. Meals containing low to medium levels of inhibitors require the addition of AA at a molar ratio of 2:1 (e.g., 20 mg AA: 3 mg iron). To promote absorption in the presence of high levels of inhibitors, AA needs to be added at a molar ratio in excess of 4:1, which may be impractical. The effectiveness of AA in promoting absorption from less soluble compounds, such as ferrous fumarate and elemental iron, requires further investigation. The instability of AA during food processing, storage, and cooking, and the possibility of unwanted sensory changes limits the number of suitable food vehicles for AA, whether used as vitamin fortificant or as an iron enhancer. Suitable vehicles include dry-blended foods, such as complementary, precooked cereal-based infant foods, powdered milk, and other dry beverage products made for reconstitution that are packaged, stored, and prepared in a way that maximizes retention of this vitamin. The consumption of natural sources of Vitamin C (fruits and vegetables) with iron-fortified dry blended foods is also recommended. Encapsulation can mitigate some of the AA losses during processing and storage, but these interventions will also add cost. In addition, the bioavailability of encapsulated iron in the presence/absence of AA will need careful assessment in human clinical trials. The long-term effect of high AA intake on iron status may be less than predicted from single meal studies. The hypothesis that an overall increase of dietary AA intake, or fortification of some foods commonly consumed with the main meal with AA alone, may be as effective as the fortification of the same food vehicle with AA and iron, merits further investigation. This must involve the consideration of practicalities of implementation. To date, programs based on iron and AA fortification of infant formulas and cow's milk provide the strongest evidence for the efficacy of AA fortification. Present results suggest that the effect of organic acids, as measured by in vitro and in vivo methods, is dependent on the source of iron, the type and concentration of organic acid, pH, processing methods, and the food matrix. The iron absorption-enhancing effect of AA is more potent than that of other organic acids due to its ability to reduce ferric to ferrous iron. Based on the limited data available, other organic acids may only be effective at ratios of acid to iron in excess of 100 molar. This would translate into the minimum presence/addition of 1 g citric acid to a meal containing 3 mg iron. Further characterization of the effectiveness of various organic acids in promoting iron absorption is required, in particular with respect to the optimal molar ratio of organic acid to iron, and associated feasibility for food application purposes. The suggested amount of any organic acid required to produce a nutritional benefit will result in unwanted organoleptic changes in most foods, thus limiting its application to a small number of food vehicles (e.g., condiments, beverages). However, fermented foods that already contain high levels of organic acid may be suitable iron fortification vehicles.

Ascorbic acid, glycation, glycohemoglobin and aging

The glycation of proteins alters both their structure and function. These changes have been linked to diabetic disorders and aging. The glycation of hemoglobin is also used as a diagnostic tool; the extent of glycation being a reflection of blood glucose averaged over a two to three month period. Accurate measures of average blood sugar (e.g., glycohemoglobin (GHb)) are important in clinical management of diabetes, pregnancy, cancer, etc. Ascorbic acid (AA) can react with proteins, including hemoglobin, and possibly interfere with GHb measurements. Past reports on the impact of AA on in vivo glycation have been equivocal. We studied GHb in subjects supplementing up to 20 g AA daily and found that for each 30 μmol/L increase in plasma AA, GHb was reduced by ∼0.1. These results suggest that high AA intake can depress glycation, reduce GHb and lead to a clinically relevant underestimation of average blood sugar. Because AA is the most commonly consumed dietary supplement, awareness of an AA-associated bias in GHb is imperative. Of even broader significance is the possibility of AA-mediated inhibition of glycation in all proteins and the implications for aging. Moreover, AA could contribute through several other mechanisms to slowing of human aging (e.g., antioxidant properties, acceleration of pentose phosphate pathway, replacement of structural proteins).

Vitamin C contributes to inflammation via radical generating mechanisms: a cautionary note

Reactive oxygen and nitrogen species (RONS) have been ascribed an important role in oxidative stress contributing to the progression of inflammatory diseases such as Crohn’s disease and rheumatoid arthritis. Redox-active metal ions such as Fe(II) and Cu(I) further activate RONS and thus perpetuate their damaging effects. High intake of ascorbic acid exerts a pro-oxidant effect by its interaction with metal ions via a number of established RONS generating systems. Caution should be exerted regarding surplus ascorbic acid intake for patients with chronic inflammatory diseases.

Total antioxidant and ascorbic acid content of fresh fruits and vegetables: implications for dietary planning and food preservation.

Epidemiological evidence links high intake of ascorbic acid (AA) and other antioxidant micronutrients to health promotion. It would be useful to know the overall, or 'total' antioxidant capacity of foods, to establish the contribution of AA to this, and to assess how this information may translate into dietary intakes to meet the new US daily reference intake for AA. In this study, the total antioxidant capacity, as the ferric reducing-antioxidant power (FRAP) value, and AA content of thirty-four types of fruits and vegetables were measured using a modified version of the FRAP assay, known as FRASC. This measures AA (reduced form only) simultaneously with the FRAP value. Results covered a wide range: 880-15940 micromol/kg fresh wet weight and <20-540 mg/kg fresh wet weight respectively, for FRAP and AA, which comprised < 1-73 % and < 1-59 % total antioxidant capacity of fruits and vegetables respectively. We estimate that 100 mg AA is contained in one orange, a few strawberries, one kiwi fruit, 1-2 slices of pineapple, several florets of raw cauliflower or a handful of uncooked spinach leaves. Apples, bananas, pears and plums, the most commonly consumed fruits in the UK, contain very little AA. Results indicate also that the antioxidant capacity of vegetables decreases rapidly and significantly after fragmentation. Results of this, and future studies, using FRASC as a biomonitoring tool will be useful in food production, preparation, preservation, and aid dietary choices to increase antioxidant and AA intake. Furthermore, FRASC will facilitate bioavailability studies of antioxidants from different foods of known antioxidant capacity and AA content.

Dietary antioxidant vitamins, retinol, and breast cancer incidence in a cohort of Swedish women

Dietary antioxidant vitamins and retinol have been proposed to be protective against breast cancer on the basis of their ability to reduce oxidative DNA damage and their role in cell differentiation. Epidemiologic studies have not been convincing in supporting this hypothesis, but women with high exposure to free radicals and oxidative processes have not been specifically considered. We explored these issues in the Swedish Mammography Screening Cohort, a large population-based prospective cohort study in Sweden that comprised 59,036 women, 40–76 years of age, who were free of cancer at baseline and who had answered a validated 67-item food frequency questionnaire. During 508,267 person-years of follow-up, 1,271 cases of invasive breast cancer were diagnosed. Cox proportional hazards models were used to obtain hazard ratios (HRs) and 95% confidence intervals (CIs). There was no overall association between intake of ascorbic acid, beta-carotene, retinol or vitamin E and breast cancer incidence. High intake of ascorbic acid was inversely related to breast cancer incidence among overweight women (HR=0.61; 95% CI 0.45–0.82, for highest quintile of intake among women with body mass index>25 kg/m2) and women with high consumption of linoleic acid (HR=0.72; 95% CI 0.52–1.02, for highest quintile of ascorbic acid intake and average consumption of more than 6 grams of linoleic acid per day). Among women with a body mass index of 25 or below, the hazard ratio for breast cancer incidence was 1.27 (95% CI 0.99–1.63), comparing the highest to the lowest quintile of ascorbic acid intake. Consumption of foods high in ascorbic acid may convey protection from breast cancer among women who are overweight and/or have a high intake of linoleic acid. © 2001 Wiley-Liss, Inc.

Dietary antioxidant vitamins, retinol, and breast cancer incidence in a cohort of Swedish women.

Dietary antioxidant vitamins and retinol have been proposed to be protective against breast cancer on the basis of their ability to reduce oxidative DNA damage and their role in cell differentiation. Epidemiologic studies have not been convincing in supporting this hypothesis, but women with high exposure to free radicals and oxidative processes have not been specifically considered. We explored these issues in the Swedish Mammography Screening Cohort, a large population-based prospective cohort study in Sweden that comprised 59,036 women, 40-76 years of age, who were free of cancer at baseline and who had answered a validated 67-item food frequency questionnaire. During 508,267 person-years of follow-up, 1,271 cases of invasive breast cancer were diagnosed. Cox proportional hazards models were used to obtain hazard ratios (HRs) and 95% confidence intervals (CIs). There was no overall association between intake of ascorbic acid, beta-carotene, retinol or vitamin E and breast cancer incidence. High intake of ascorbic acid was inversely related to breast cancer incidence among overweight women (HR=0.61; 95% CI 0.45-0.82, for highest quintile of intake among women with body mass index>25 kg/m(2)) and women with high consumption of linoleic acid (HR=0.72; 95% CI 0.52-1.02, for highest quintile of ascorbic acid intake and average consumption of more than 6 grams of linoleic acid per day). Among women with a body mass index of 25 or below, the hazard ratio for breast cancer incidence was 1.27 (95% CI 0.99-1.63), comparing the highest to the lowest quintile of ascorbic acid intake. Consumption of foods high in ascorbic acid may convey protection from breast cancer among women who are overweight and/or have a high intake of linoleic acid.

Ascorbic acid metabolism in fish: is there a maternal effect on the progeny?

High maternal ascorbic acid intakes have been shown to ‘condition’ the ascorbic acid requirement of guinea pig offspring. To examine whether a similar effect exists in fish, and what the relative importance of both maternal and offspring ascorbic acid intake is on offspring performance, rainbow trout offspring from females fed high (360 mg kg −1) or ascorbic acid free (0 mg kg −1) diets were maintained on both a high (500 mg kg −1) or marginal (20 mg kg −1) ascorbic acid diet. A high ascorbic acid status of the egg protected hatched fry against increased mortality due to a marginal ascorbic acid intake. Mortality of high ascorbic acid offspring was not affected by the dietary ascorbic acid level until after 18 weeks of initiation of exogenous feeding. However, the marginal diet did result in a significantly lower individual weight starting at Week 7 (final body weight: 2.5 ± 0.4 g, marginal ascorbic acid and 4.8 ± 0.6 g, high ascorbic acid intake). Ascorbic acid deficient offspring fed a marginal ascorbic acid diet showed continuously high mortalities, reaching 92.3 ± 1.9% after 15 weeks. Feeding the high ascorbic acid diet to the ascorbic acid deficient offspring led to significant growth recoveries. Final individual fish weight was not significantly different between the ascorbic acid deficient or the high ascorbic acid offspring fed a high ascorbic acid diet. Survival of both groups fed a high ascorbic acid diet were identical from Week 7 onwards. However, the initially higher mortality in the low ascorbic acid offspring resulted in a significantly higher (71.1 ± 2.2% vs 59.6 ± 6.4%) cumulative mortality. Experiments with radiolabeled ascorbic acid did not reveal significant differences in ascorbic acid conservation after 3 months of feeding.

Vitamin C Nutriture Has Little Short-Term Effect on Vitamin E Concentrations in Healthy Women

To determine whether the postulated sparing effect of vitamin E by ascorbic acid (AA) is important for human nutrition, we studied vitamin E status in 20 healthy pre-menopausal women (age 20–43 y) with high or low vitamin C intakes for 6 wk in a live-in metabolic unit. The experimental diet contained no fruits and vegetables and provided 5 mg/d of AA (Recommended Dietary Allowance = 60 mg/d), 3 mg/d of α-tocopherol (RDA = 10 mg/d) and 42 g/d of tocopherol-stripped safflower oil to increase the vitamin E requirement. Half of the subjects received a daily AA supplement of 495 mg (high AA group). A biochemical ascorbate deficiency was attained in the low AA group as indicated by plasma AA concentrations that reached the lower limit of normal by study d 15. Oral doses (20 mg) of hexadeuterated RRR-α-tocopherol acetate (d6-αT) were given daily to all subjects on d 15–21. Measures of vitamin E status included d6-αT and unlabeled α-tocopherol concentrations in plasma, platelets, buccal cells and adipose. The levels of unlabeled α-tocopherol decreased over time in plasma and platelets and were unchanged for buccal cells and adipose, but were not significantly affected by AA intake. Likewise, the rise and fall of plasma and platelet d6-αT, and measures of lipid peroxidation, were not affected by AA intake. Although vitamin C nutriture did not significantly affect vitamin E status within the 6-wk time period of this experiment, further study of this question is warranted, because some of the present results indicate a trend toward sparing of tissue tocopherol by high AA intake.

The effect of 2,4-dichlorophenol on lipid peroxidation in tissues of guinea pigs with different ascorbic acid intake.

Chlorinated phenols are widely used in the manufacture of biocides and wood preservatives. 2,4-dichlorophenol administered perorally 3 times a week at a dose of 40 mg in 0.2 ml of olive oil per kg of body weight to guinea pigs increased lipid peroxidation in liver and adrenals after 2 weeks of treatment. A high intake of ascorbic acid (50 mg/animal/day) significantly decreased lipid peroxidation in the liver of 2, 4-dichlorophenol treated guinea pigs in comparison to guinea pigs with low ascorbic acid intake (2 mg/animal/day). 2,4-dichlorophenol accumulation was also decreased in the liver of animals with high ascorbic acid intake. Increased daily intake of vitamin C to persons involved in production and use of chlorophenoxy herbicides is recommended.

Histopathological evidence of vitamin C protection against Cd-nephrotoxicity in Guinea pigs

The critical organ of chronic cadmium (Cd) exposure are kidneys. Long-term exposure leads to Cd accumulation in kidneys and causes renal tubular dysfunctions. Cd-induced renal changes are irreversible, so the primary prevention by different nutrients can play an important role. In this study, male guinea pigs which, like humans, do not synthetize ascorbic acid (AA) received low (2 mg/animal/day) or high (100 mg/animal/day) dosage of AA and cadmium (1 mg Cd/animal/day) in drinking water for 12 weeks. Characteristic finding in renal morphology of Cd-intoxicated guinea pigs was dilatation of interstitial veins with apparent paravenous lymphatic infiltrates. Histomorphological changes were more evident in Cd-intoxicated guinea pigs with low AA intake. High AA intake apparently reduced in Cd-intoxicated guinea pigs the extent of renal damage. Cadmium significantly increased serum creatinine and urea levels in the group of guinea pigs with low AA intake but not in guinea pigs receiving high concentration of AA. The results showed that AA can be effective in the protection of Cd-induced nephrotoxicity.

Effect of cadmium on hepatic microsomal monooxygenase activities in guinea pigs with low and high ascorbic acid intake

The influence of in vivo administration of cadmium on hepatic microsomal cytochrome P-450 and cytochrome b 5 content, aniline hydroxylase, p-nitroanisole O-demethylase, and NADPH-cytochrome c reductase activities was investigated in guinea pigs with low (2 mg/animal/day) and high (100 mg/animal/day) ascorbic acid intake. Male guinea pigs received 10 mg Cd/L drinking water for 5 and 12 weeks. Cadmium administration resulted in significant decreases in cytochrome P-450 content and NADPH-cytochrome c reductase activity in the group of guinea pigs with low ascorbic acid intake, while the decreases were less evident in guinea pigs with high ascorbic acid intake. The activities of aniline hydroxylase and O-demethylase were not apparently changed by Cd administration, except for the group of guinea pigs with high ascorbic acid intake in 12th week of cadmium treatment, when increased activities were observed. These findings suggest that hepatotoxic effect of cadmium manifested by inhibition of hepatic microsomal metabolism may be in part beneficially moderated by enhanced ascorbic acid intake.

The influence of ascorbic acid on lipid peroxidation in guinea pigs intoxicated with cadmium

Cadmium (as CdCl 2) administered at a dose of 1 mg Cd/animal/day in drinking water to guinea pigs with a low intake of ascorbic acid (2 mg/animal/day) increased lipid peroxidation (LPO) in the kidney, liver and serum after 5 wk of treatment. A high intake of ascorbic acid (100 mg/animal/day) decreased LPO (determined from malondialdehyde levels) in the kidney, liver and serum of Cd-treated guinea pigs. Administration of Cd to guinea pigs with a low intake of ascorbic acid significantly increased LPO in the kidney at 5 wk, in comparison with controls given low levels of ascorbic acid but no Cd. However, at 12 wk, LPO in the kidney of Cd-treated guinea pigs was significantly lower than in the controls. These results indicate that the level of lipid peroxides in the kidney of guinea pigs with a low intake of ascorbic acid depends on the amount of accumulated cadmium.

Metabolism of Ascorbic-1-,14C Acid in Experimental Human Scurvy

A study of the metabolism of ascorbic-l-“C acid in experimental human scurvy was conducted with the following results: I) Labeling the body ascorbic acid pool during the depletion phase resulted in no detectable urinary excretion of l%-labeled reduced ascorbic acid or & hydroascorbic acid. by all subjects occurred as a first order process during the depletion phase. The urinary “C excretion curves of the four subjects did not differ from the average man by more than -t 3%. despite marked differences in body weight and age. 3) First symptoms of mild scurvy appeared in the subjects when their body ascorbic acid pool had been reduced to approximately 300 mg. 4) Once the body pool of ascorbic acid was repleted to a level of 1.5 g, urinary loss of reduced ascorbic acid occurred. 5) The rate of repletion of ascorbic acid was found to be a zero-arder process and pportional to the level of daily ascorbic acid intake. a) When the subjects were fed a high intake of ascorbic acid, only a limited quantity of the ingested vitamin was equilibrated with the IT-labeled ascorbatc pool. 7) All of the radioactivity exmted during the depletion phase was in the form of 2) Urinary excretion of stable organic material that did not behave as ascorbic acid. This organic material was scpamtd into four unknowo compounds. 8) The daily intake of 6.5 -day of ascorbic acid was sufficient to alleviate and cure theclinicpl signs of scurvy in one man.

Plasma Cortisol and Adrenal Ascorbic Acid Levels after ACTH Treatment with a High Intake of Ascorbic Acid in the Guinea Pig

The influence of ascorbic acid (AA) intake on plasma cortisol (PC) and tissue AA levels after ACTH treatment was examined using guinea pigs. ACTH produced an 8- to 10-fold rise in PC levels (p less than 0.0001) over the 4-hour experimental period compared to gel-injected control animals. The magnitude of rise in PC was similar at both normal (0.50 g/kg diet) and high (10 g/kg diet) AA intakes. A 30-100% higher (p less than 0.0001) level of AA in tissues (adrenals, liver, and kidneys) and plasma was observed with the high AA diet. ACTH resulted in a 26-30% lower level of AA in the adrenals (p less than 0.0001), but not in other tissues or plasma. PC and adrenal AA responses were unrelated (r = -0.326). These results suggest that ACTH alters AA only in the adrenals, the PC response to and percent decrease in adrenal AA levels with ACTH are not related to AA status, and the absolute level of AA in the adrenals is not critical for steroidogenesis.

Growth, ascorbic acid and iron contents of tissues of young guinea-pigs whose dams received high or low levels of dietary ascorbic acid or Fe during pregnancy and suckling.

1. Guinea-pig dams were fed on purified diets containing high (5 g/kg diet plus 1 g/l drinking water) or moderate (0.5 g/kg diet) levels of ascorbic acid, in combination with high (1 g/kg diet) or moderate (0.043 g/kg diet) levels of iron, during pregnancy and suckling. Their offsprings' diets contained 0.1 g ascorbic acid/kg and 0.04 g Fe/kg. 2. High ascorbic acid intake clearly enhanced both tissue ascorbate and Fe storage in the dams, and high Fe intake increased both the dams' and the pups' tissue Fe stores. 3. In the animals receiving high Fe intake, a co-existing high ascorbate intake by the dams reduced the growth rate of the offspring, but only during the early stages of development, not during the later stages of post-weaning growth. All the pups' tissue ascorbate levels fell after weaning, but those born of the dams receiving the high ascorbic acid diets did not fall to levels lower than those of the other pups. 4. Thus, although certain disadvantages to the offspring resulting from very-high ascorbic acid intake by pregnant guinea-pig dams were detected, these did not include permanently increased ascorbate requirements, and hence a progression to scurvy as the pups grew and matured.

Effects of ascorbic acid supplements and a diet marginal in copper on indices of copper nutriture in women

Biochemical indicators of copper status were studied in young women housed in a metabolic unit for 135 days. The women were fed a diet low in Cu (0.67 mg/d), that was supplemented with 1.5 g of ascorbic acid and variable amounts of copper. Copper balance was not significantly affected by diet. Plasma copper and monoamine oxidase, and erythrocyte superoxide dismutase were not affected by dietary copper or by ascorbic acid. Enzymatic (CpENZ), but not immunoreactive (CpRID), ceruloplasmin was lower at the end of low copper intake and high ascorbic acid intake periods. The specific activity of ceruloplasmin (CpENZ/CpRID) was significantly lower at the end of the ascorbic acid period (1.26) than at either the end of control (1.81) or repletion (1.80) periods, and slightly lower than after only low copper intake (1.44). Cytochrome-c oxidase activities in platelets and leukocytes were significantly affected by copper intake, but not ascorbic acid intake. These findings indicate that the specific activity of ceruloplasmin and cytochrome-c oxidase activity of platelets and white cells may be sensitive indicators of copper status, and that ascorbic acid supplements do not markedly affect commonly measured indices of copper metabolism, except for the specific activity of ceruloplasmin in young women.

Effect of Varying Ascorbic Acid Intakes on Copper Absorption and Ceruloplasmin Levels of Young Men

Intestinal copper absorption and blood measures of copper status were studied in healthy young men receiving varying intakes of ascorbic acid (AA) over 14 wk in a live-in nutrition suite. Copper absorption and retention were assessed by measuring absorption of a stable isotope of copper and total fecal copper during four AA intake periods: 2 wk × 65 mg AA/d, 4 wk × 5 mg/d, 3 wk × 605 mg/d and 4 wk × 5 mg/d. Measures of copper status were serum copper and serum ceruloplasmin determined by both enzymatic and immunochemical methods. Copper absorption, copper retention, total serum copper and the serum level of ceruloplasmin protein were not affected significantly by the changes in AA intake; however, the oxidase activity of serum ceruloplasmin was decreased an average of 21% during the high (605 mg/d) AA intake period. The results suggest that in adult men moderate supplemental intakes of AA reduce ceruloplasmin oxidase activity specificially but do not depress intestinal copper absorption or overall body copper status.

Myocardial calcinosis associated with hemodialysis

Increased plasma oxalic acid concentrations have been found in patients with chronic renal failure. Secondary oxalosis in patients on chronic hemodialysis is caused by impaired renal excretion and inadequate removal of oxalic acid during hemodialysis. 1,2 The oral or intravenous administration of ascorbic acid aggravates the elevated plasma oxalic acid in patients on hemodialysis. 3 As a consequence of increased plasma oxalic acid levels, calcium oxalate deposits have been found in myocardium and other organs. 4 We report a patient treated with chronic hemodialysis with diffuse calcinosis in the myocardium at autopsy. In this patient, who had undergone parathyroidectomy, a high intake of ascorbic acid led to increased oxalic acid synthesis and calcium deposits in many tissues.

Evidence of rebound effect with ascorbic acid

The urinary excretion pattern of ascorbic acid in two subjects who had been taking a large amount of ascorbic acid (10 g per day) and later reverted to a small intake (125 mg per day) is described. The ascorbic acid concentration in the 24-hour urine samples was measured over a 40-day collection of this period. The mean urinary ascorbic acid excretion during the loading period of the two subjects was about 2 g per day. Upon termination of the high intake of ascorbic acid, urinary ascorbic acid excretion dropped to presupplementation levels within 6 days. Urinary ascorbic acid of the two subjects continued to decrease to below basal level, and remained at abnormally low levels for 10 and 12 days respectively. We hypothesize that the high intake of ascorbic acid has induced the formation of increased amounts of enzymes that help convert the ascorbic acid into other substances and that these substances are valuable. Some possible physiological actions of these ascorbic acid metabolites are discussed.

Influence of ascorbic acid supplementation on copper status in young adult men

The influence of ascorbic acid supplementation on the copper status of young adult men was investigated. Subjects consuming self-selected diets took 500 mg of ascorbic acid with each meal (1500 mg/day) for 64 days. Blood samples were obtained at 0, 28, 52, and 64 days in order to determine serum copper and serum ceruloplasmin. Each subject thus served as his own control. Analyses were repeated 20 days after the ascorbic acid supplement was terminated. Serum ceruloplasmin activity was significantly reduced (p less than 0.01) at every data point throughout the ascorbic acid supplementation period. A similar but nonsignificant trend was observed for serum copper. Furthermore there was a significant increase (p less than 0.01) in serum copper concentration 20 days after the supplementation period. Although observed effects occurred within physiological ranges of normal values, this study confirms that a high ascorbic acid intake is antagonistic to copper status of men as has been demonstrated in laboratory animals.