Examining the diet quality of Canadian adults and the alignment of Canadian front-of-pack labelling regulations with other front-of-pack labelling systems and dietary guidelines.

Introduction: Canada promulgated mandatory front-of-pack labelling (FOPL) regulations in 2022, requiring pre-packaged foods meeting and/or exceeding recommended thresholds for nutrients-of-concern (i.e., saturated fat, sodium, sugars) to display a "high-in" nutrition symbol. However, there is limited evidence on how Canadian FOPL (CAN-FOPL) regulations compare to other FOPL systems and dietary guidelines. Therefore, the objectives of the study were to examine the diet quality of Canadians using the CAN-FOPL dietary index system and its alignment with other FOPL systems and dietary guidelines. Methods: Nationally representative dietary data from the 2015 Canadian Community Health Survey-Nutrition survey (n = 13,495) was assigned dietary index scores that underpin CAN-FOPL, Diabetes Canada Clinical Practice (DCCP) Guidelines, Nutri-score, Dietary Approaches to Stop Hypertension (DASH) and Canada's Food Guide (Healthy Eating Food Index-2019 [HEFI-2019]). Diet quality was examined by assessing linear trends of nutrient intakes across quintile groups of CAN-FOPL dietary index scores. The alignment of CAN-FOPL dietary index system compared with other dietary index systems, with HEFI as the reference standard, was examined using Pearson's correlations and к statistics. Results: The mean [95% CI] dietary index scores (range: 0-100) for CAN-FOPL, DCCP, Nutri-score, DASH, and HEFI-2019 were 73.0 [72.8, 73.2], 64.2 [64.0, 64.3], 54.9 [54.7, 55.1], 51.7 [51.4, 51.9], and 54.3 [54.1, 54.6], respectively. Moving from the "least healthy" to the "most healthy" quintile in the CAN-FOPL dietary index system, intakes of protein, fiber, vitamin A, vitamin C, and potassium increased, while intakes of energy, saturated fat, total and free sugars, and sodium decreased. CAN-FOPL showed moderate association with DCCP (r = 0.545, p < 0.001), Nutri-score (r = 0.444, p < 0.001), and HEFI-2019 (r = 0.401, p < 0.001), but poor association with DASH (r = 0.242, p < 0.001). Slight to fair agreement was seen between quintile combinations of CAN-FOPL and all dietary index scores (к = 0.05-0.38). Discussion: Our findings show that CAN-FOPL rates the dietary quality of Canadian adults to be healthier than other systems. The disagreement between CAN-FOPL with other systems suggest a need to provide additional guidance to help Canadians select and consume 'healthier' options among foods that would not display a front-of-pack nutrition symbol.

Nutrient intakes and top food categories contributing to intakes of energy and nutrients-of-concern consumed by Canadian adults that would require a 'high-in' front-of-pack symbol according to Canadian labelling regulations.

Canada recently mandated front-of-pack (FOP) labelling regulations, where foods meeting and/or exceeding recommended thresholds for nutrients-of-concern (i.e., saturated fat, sodium, and sugars) must display a 'high-in' FOP nutrition symbol. However, there is limited research on the amounts and sources of foods consumed by Canadians that would require a FOP symbol. The objective was to examine the intakes of nutrients-of-concern from foods that would display a FOP symbol and to identify the top food categories contributing to intakes for each nutrient-of-concern. Using the first day 24-hour dietary recall from the nationally representative 2015 Canadian Community Health Survey-Nutrition (CCHS), Canadian adults' intakes of nutrients-of-concern from foods that would display a FOP symbol was examined. Foods were assigned to 1 of 62 categories to identify the top food categories contributing to intakes of energy and nutrient-of-concern that would display a FOP symbol for each nutrient-of-concern. Canadian adults (n = 13,495) consumed approximately 24% of total calories from foods that would display a FOP symbol. Foods that would display a FOP symbol for exceeding thresholds for nutrients-of-concern accounted for 16% of saturated fat, 30% of sodium, 25% of total sugar, and 39% of free sugar intakes among Canadian adults. The top food category contributing intakes of each nutrient-of-concern that would display a FOP symbol were nutrient-specific: Processed meat and meat substitutes for saturated fat; Breads for sodium; and Fruit juices & drinks for total and free sugars. Our findings show that Canadian FOP labelling regulations have the potential to influence the intakes of nutrients-of-concern for Canadian adults. Using the findings as baseline data, future studies are warranted to evaluate the impact of FOP labelling regulations.

Iodine Status of Canadian Children, Adolescents, and Women of Childbearing Age.

BACKGROUND: Adequate iodine intake is important for children and women of childbearing age because iodine is vital for fetal brain development and early life. OBJECTIVE: Iodine status of children (n = 1875), adolescents (n = 557), and women of childbearing age (n = 567) was assessed using urinary iodine concentrations (UIC) from duplicate spot samples collected in the Canadian Health Measures Survey, cycle 5 (2016-2017). METHODS: Daily iodine intakes were estimated from urinary iodine and creatinine concentrations using a formula based on iodine absorption and predicted 24-h creatinine excretion. Usual UIC and iodine intakes, adjusted for within-person variation, were estimated using the National Cancer Institute method. Iodine status was assessed by 1) comparing median UIC with WHO/UNICEF/ICCIDD reference ranges and 2) estimating the prevalence of inadequate and excessive intakes using the estimated average requirement (EAR) and tolerable upper intake level (UL) cut-point method, respectively. RESULTS: Median UIC for males and females 6-11 or 12-19 y old were ≥100 µg/L, the lower cutoff for adequate intakes. For women 20-39 y old, the median UIC of an unadjusted sample was 81 µg/L (95% CI: 67, 95) and for the usual UIC was 108 µg/L (95% CI: 84, 131). The percentage of children 3 y old with iodine intake ≥EAR was 82% (95% CI: 75, 89). The corresponding estimates for males 4-8, 9-13, and 14-18 y old were 93% (95% CI: 88, 97), 91% (95% CI: 87, 96), and 84% (95% CI: 76, 91), respectively. Estimates for females 4-8, 9-13, 14-18, and 19-39 y old were 86% (95% CI: 83, 89), 87% (95% CI: 80, 95), 68% (95% CI: 55, 80), and 68% (95% CI: 59, 76), respectively. For all sex-age groups, 91-100% had iodine intakes ≤UL. CONCLUSIONS: Iodine intakes may be insufficient for some women of childbearing age. Public health policies and programs should continue to recommend that all women who could become pregnant, or women who are pregnant or breastfeeding, take a daily multivitamin-mineral supplement containing iodine.

Progress towards eliminating industrially produced trans-fatty acids in the Canadian marketplace, 2013-2017.

OBJECTIVE: To assess the prevalence of partially hydrogenated oils (PHO), hydrogenated oils (HO) and/or both in Canadian packaged foods in 2013 and 2017 and to determine the mean trans-fatty acid (TFA) content of products declaring such oils. DESIGN: Repeated cross-sectional study of the Food Label Information Program. SETTING: Food labels (n 32 875) were collected from top Canadian grocery retailers in 2013 and 2017. Proportions of products declaring PHO, HO and/or both in the Ingredients List were calculated by year and food category. The percentage contribution of TFA (g) to total fat (g) was calculated and compared against the voluntary TFA limits, defined as <2 % of total fat content for fats and oils, and <5 % for all other foods. Foods exceeding limits were identified. The mean TFA content (in g/serving and per 100 g) was calculated for products with these oils. RESULTS: The use of PHO, HO and/or both significantly decreased in Canadian foods from 2013 to 2017 (0·8 to 0·2 %, 5 to 2·4 % and 5·7 to 2·6 %, respectively, for PHO, HO and/or both). The mean TFA content of products containing PHO increased (0·34 to 0·57 g TFA/serving); although it was not statistically significant, it is still concerning that TFA content increased. The TFA content significantly decreased in foods with HO (0·24 to 0·16 g TFA/serving, P < 0·05) during 2013-2017. CONCLUSIONS: Products with PHO continue to be present in the Canadian marketplace, despite voluntary efforts to eliminate them. Products with HO should also be monitored, as they can also contribute to TFA content in foods.

Sodium-Reduced Meat and Poultry Products Contain a Significant Amount of Potassium from Food Additives.

BACKGROUND: Sodium-reduced packaged food products are increasingly available to consumers; however, it is not clear whether they are suitable for inclusion in a potassium-reduced diet. For individuals with impaired renal potassium excretion caused by chronic kidney disease and for those taking certain medications that interfere with the rennin-angiotensin aldosterone axis, the need to limit dietary potassium is important in view of the risk for development of hyperkalemia and fatal cardiac arrhythmias. OBJECTIVE: The primary objective of this study was to determine the impact of the reduction of sodium in packaged meat and poultry products (MPPs) on the content of potassium and phosphorus from food additives. DESIGN: This was a cross-sectional study comparing chemically analyzed MPPs (n=38, n=19 original, n=19 sodium-reduced), selected from the top three grocery chains in Canada, based on market share sales. All MPPs with a package label containing a reduced sodium content claim together with their non-sodium-reduced packaged MPP counterparts were selected for analysis. The protein, sodium, phosphorus, and potassium contents of sodium-reduced MPPs and the non-sodium-reduced (original) MPP counterparts were chemically analyzed according to the Association of Analytical Communities official methods 992.15 and 984.27 and compared by using a paired t test. The frequency of phosphorus and potassium additives appearing on the product labels' ingredient lists were compared between groups by using McNemar's test. RESULTS: Sodium-reduced MPPs (n=19) contained 44% more potassium (mg/100 g) than their non-sodium-reduced counterparts (n=19) (mean difference [95% CI): 184 [90-279]; P=0.001). The potassium content of sodium-reduced MPPs varied widely and ranged from 210 to 1,500 mg/100 g. Potassium-containing additives were found on the ingredient list in 63% of the sodium-reduced products and 26% of the non-sodium-reduced products (P=0.02). Sodium-reduced MPPs contained 38% less sodium (mg/100 g) than their non-sodium-reduced counterparts (mean difference [95% CI]: 486 [334-638]; P<0.001). The amounts of phosphorus and protein, as well as the frequency of phosphorus additives appearing on the product label ingredient list, did not significantly differ between the two groups. CONCLUSIONS: Potassium additives are frequently added to sodium-reduced MPPs in amounts that significantly contribute to the potassium load for patients with impaired renal handling of potassium caused by chronic kidney disease and certain medications. Patients requiring potassium restriction should be counseled to be cautious regarding the potassium content of sodium-reduced MPPs and encouraged to make food choices accordingly.

Traffic-light labels could reduce population intakes of calories, total fat, saturated fat, and sodium.

Traffic-light labelling has been proposed as a public health intervention to improve the dietary intakes of consumers. OBJECTIVES: to model the potential impact of avoiding foods with red traffic lights on the label on the energy, total fat, saturated fat, sodium, and sugars intakes of Canadian adults. METHODS: Canadian adults aged 19 and older (n = 19,915) who responded to the Canadian Community Health Survey (CCHS), Cycle 2.2. The nutrient levels in foods consumed by Canadians in CCHS were profiled using the United Kingdom's criteria for traffic light labelling. Whenever possible, foods assigned a red traffic light for one or more of the profiled nutrients were replaced with a similar food currently sold in Canada, with nutrient levels not assigned any red traffic lights. Average intakes of calories, total fat, saturated fat, sodium, and sugars under the traffic light scenario were compared with actual intakes of calories and these nutrients (baseline) reported in CCHS. RESULTS: Under the traffic light scenario, Canadian's intake of energy, total fat, saturated fat, and sodium were significantly reduced compared to baseline; sugars intakes were not significantly reduced. Calorie intake was reduced by 5%, total fat 13%, saturated fat 14%, and sodium 6%. CONCLUSION: Governments and policy makers should consider the adoption of traffic light labelling as a population level intervention to improve dietary intakes and chronic disease risk.

trans Fatty acids in the Canadian food supply: an updated analysis.

BACKGROUND: Dietary trans fatty acids (TFAs) increase the risk of heart disease. In 2007, Canada set voluntary TFA limits for industrial TFAs added to food and encouraged substitution of TFAs with unsaturated fats during reformulation. No longitudinal follow-up assessment of TFA amounts in foods has occurred in Canada since termination of a government-led Trans Fat Monitoring Program (TFMP). OBJECTIVE: The objective was to conduct an updated assessment and longitudinally evaluate TFA amounts in the food supply and to determine whether saturated fats have replaced TFAs in reformulation. DESIGN: This was a cross-sectional study that used 3 databases: TFMP (Health Canada, 2005-2009; n = 921), the University of Toronto Food Label Information Program (2010-2011; n = 5544), and the Restaurant Database (2010; n = 4272). Outcomes were TFAs as a percentage of fat, proportion of foods meeting TFA limits, and saturated fat amounts in foods with high or low TFAs. RESULTS: The proportion of foods meeting TFA limits improved from 75% in 2005-2009 to 97% in 2010-2011, particularly in the following packaged foods: croissants (25% to 100%), pies (36% to 98%), cakes (43% to 90%), and garlic spreads (33% to 100%). Most restaurant categories assessed by the TFMP had 100% of foods meeting TFA limits. Some categories had a large proportion that exceeded TFA limits: dairy-free cheeses (100%), frosting (72.0%), lard and shortening (66.7%), coffee whiteners (66.7%), and restaurant-prepared biscuits and scones (47.4%). Saturated fat amounts were significantly higher (P < 0.05) among some foods with the lowest TFAs, such as cookies, brownies and squares, cakes with pudding/mousse, dessert toppings, and lard and shortening. CONCLUSIONS: There has been an impressive improvement in TFA amounts in the Canadian food supply since the termination of the TFMP. However, action by the food industry is required to reduce TFAs in foods that exceed the recommended TFA limits and to minimize the use of saturated fats in replacing TFAs during reformulation.

Examining the effects of increased vitamin D fortification on dietary inadequacy in Canada.

OBJECTIVES: Despite mandatory fortification of milk and margarine, most Canadians have inadequate vitamin D intake and consequently poor vitamin D status, especially in the winter. Increasing vitamin D fortification is one possible strategy to address this inadequacy. The purpose of our study was to examine the modelled effect of increased vitamin D fortification on the prevalence of inadequacy and the percentage of intakes greater than the Tolerable Upper Intake Level (UL) using different fortification scenarios. METHODS: Dietary intakes (24-h recall) from the 2004 Canadian Community Health Survey 2.2 (n=34,381) were used to model increased vitamin D levels in milk and the addition of vitamin D to cheese and yogurt at various levels to meet label claims of an "excellent source" based on the recommended dietary intakes. The Software for Intake Distribution Evaluation was used to estimate the prevalence of inadequacy and intakes >UL. RESULTS: Fortification of milk, yogurt and cheese at 6.75 µg (270 IU)/serving led to more than doubling of vitamin D intakes across all sex/age groups and a drop in the prevalence of dietary inadequacy from >80% to <50% in all groups. Furthermore, no intakes approached the UL under any fortification scenario in any sex/age group. CONCLUSION: There is a pressing need to improve vitamin D status among Canadians. Increasing vitamin D fortification of dairy products, consistent with their positioning in Canada's Food Guide, can lead to increased intake without a risk of excess. This is a population-wide public health strategy that should be given consideration in Canada.

Zinc supplementation does not alter sensitive biomarkers of copper status in healthy boys.

The tolerable upper intake levels (UL) for zinc for children were based on limited data and there is concern that the UL may be set too low. The first effect of excessive zinc intake is a reduction in copper status. The primary objective of this study was to examine the effect of zinc supplementation on copper status in children. Healthy, 6- to 8-y-old boys from Ontario, Canada were assigned to take a placebo (n = 10) or 5 mg (n = 10), 10 mg (n = 9), or 15 mg (n = 8) of zinc supplement daily for 4 mo in a double-blinded, placebo-controlled, randomized trial. Biochemical measures were evaluated at baseline and after 2 and 4 mo of supplementation. Food records were completed near the baseline and 4-mo visits. Age and anthropometric measurements did not differ (P > 0.05) between treatment groups at baseline. Mean zinc intakes from food alone (10.9-14.8 mg zinc/d) approached or exceeded the UL of 12 mg/d. Compared with the placebo group, the zinc groups had a greater change in the urine zinc:creatinine ratio at 4 mo (P = 0.02). Traditional (plasma copper and ceruloplasmin activity) and more sensitive biomarkers of copper status, including erythrocyte SOD1 activity and the erythrocyte CCS:SOD1 protein ratio, were unchanged in zinc-supplemented boys, demonstrating that copper status was not depressed. Serum lipid measures and hemoglobin concentrations were also unaffected and gastrointestinal symptoms were not reported. These data provide evidence in support of the need for reexamining the current UL for zinc for children.

Trans and saturated fat on food labels in Canada: fact or fiction?

OBJECTIVE: Food labels are the number one source for nutrition information for Canadians, but are food labels accurate? This study aims to provide an assessment of the accuracy of the reported trans fatty acid and saturated fatty acid values on food labels in selected foods. METHODS: Over 380 samples of cookies, crackers, granola bars, breakfast bars and a variety of frozen foods were collected between 2005 and 2008 in the Greater Toronto Area, Ottawa and Vancouver, as part of Health Canada's Trans Fat Monitoring Program. The food categories chosen were based on earlier studies indicating that they were significant sources of trans fatty acids and the individual samples were chosen based on market share data. The trans fatty acid and saturated fatty acid contents of the samples were determined by gas chromatography and the laboratory results were compared to the values reported in the Nutrition Facts tables. CONCLUSIONS: Statistical analysis indicated no significant difference between laboratory and food label values for cookies, crackers, granola bars, breakfast bars and frozen foods for trans fat or saturated fat. The results demonstrate that Canadians can rely on food labels for making informed dietary choices with respect to trans fat and saturated fat content.

Executive summary--Biomarkers of Nutrition for Development: Building a Consensus.

The ability to develop evidence-based clinical guidance and effective programs and policies to achieve global health promotion and disease prevention goals depends on the availability of valid and reliable data. With specific regard to the role of food and nutrition in achieving those goals, relevant data are developed with the use of biomarkers that reflect nutrient exposure, status, and functional effect. A need exists to promote the discovery, development, and use of biomarkers across a range of applications. In addition, a process is needed to harmonize the global health community's decision making about what biomarkers are best suited for a given use under specific conditions and settings. To address these needs, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, US Department of Health and Human Services, organized a conference entitled "Biomarkers of Nutrition for Development: Building a Consensus," which was hosted by the International Atomic Energy Agency. Partners included key multilateral, US agencies and public and private organizations. The assembly endorsed the utility of this initiative and the need for the BOND (Biomarkers of Nutrition for Development) project to continue. A consensus was reached on the requirement to develop a process to inform the community about the relative strengths or weaknesses and specific applications of various biomarkers under defined conditions. The articles in this supplement summarize the deliberations of the 4 working groups: research, clinical, policy, and programmatic. Also described are content presentations on the harmonization processes, the evidence base for biomarkers for 5 case-study micronutrients, and new frontiers in science and technology.

Effect of calcium on iron absorption in women with marginal iron status.

We measured non-haem Fe absorption with and without added Ca in a short-term feeding study, in thirteen women with marginal Fe status, by the use of a double stable isotope technique. Supplementing 500 mg Ca as calcium carbonate significantly (P = 0.0009) reduced Fe absorption from a single meal from 10.2 % (range 2.2-40.6) to 4.8 % (range 0.7-18.9). A significant inverse correlation in the absence ( - 0.67, P = 0.010) and presence ( - 0.58, P = 0.037) of Ca, respectively, was found between Fe absorption and Fe stores measured by serum ferritin (SF). Wide variation in Fe absorption was observed between individuals in the absence and in the presence of Ca, despite pre-selection of participants within a relatively narrow range of iron stores (SF concentrations). Correction of Fe absorption data based on group mean SF was not found to be useful in reducing the inter-individual variability in iron absorption. It appears that selecting a study group with a narrow initial range of Fe stores does not necessarily reduce the inter-individual variability in Fe bioavailability measurements. These results support the hypothesis that body Fe stores, although an important determinant of dietary Fe absorption, are not the main factor that determines Fe absorption under conditions of identical dietary intake in subjects with low Fe stores.

Trans fatty acids: current contents in Canadian foods and estimated intake levels for the Canadian population.

Research conducted in the mid-1990s indicated that the levels of trans fats in Canadian diets were among the highest in the world. The consumption of trans fats raises blood levels of low-density lipoprotein (LDL)-cholesterol, while reducing levels of high-density lipoprotein (HDL)-cholesterol. In June 2007, Health Canada called on the food industry to voluntarily reduce levels of trans fats in vegetable oils and soft (tub)-margarines to < 2% of total fat, and in all other foods, to < 5%. Industry must show satisfactory progress by June 2009, or Health Canada might have to introduce legislation to ensure that recommended limits are achieved. Since 2005, Health Canada has been performing a national assessment of prepackaged and restaurant foods that likely contain trans fats. From 2005 to 2009, 1120 samples were analyzed, of which 852 or approximately 76% met the recommended trans fat limits. As a result of reformulation, most of the products had decreased trans + saturated fat content. The estimated average intake of trans fatty acids (TFA) in Canada significantly dropped from the high value of 8.4 g/day in the mid-1990s to 3.4 g/day (or 1.4% food energy) in 2008. However, this TFA intake of 1.4% of energy is still above the World Health Organization recommended limit of TFA intake of < 1% of energy, which suggests that the Canadian food industry needs to put more effort into reducing the TFA content in its products, especially in tub-margarines, donuts, and bakery products.

Regulatory frameworks for copper considering chronic exposures of the population.

Copper is an essential nutrient that is toxic in excess. Copper intakes from a balanced diet appear to meet the needs of most healthy individuals, because overt deficiency and toxicity are rare. Some uncertainty, however, persists because of limitations in currently available biomarkers used to assess copper status and the paucity of data available to establish tolerable upper levels of intake. Current policies and regulations pertaining to food fortification, nutritional supplements, and drinking water appear to be effective in providing for adequate copper intakes in many populations, although high levels of exposure, through overzealous fortification, supplementation, or drinking water exposure, may be possible under some circumstances. Surveillance and monitoring programs to evaluate copper exposures of human populations should continue and should be refined as new biomarkers become available.

Health claims on foods in Canada.

Interest in the health effects of foods by both industry and consumers has put a spotlight on the role of health claims on foods in Canada. The current regulatory framework governing the use of different health claims on foods in Canada is described and compared with international approaches. Similarities were observed in how risk-reduction claims for serious diseases are managed in the United States, European Union and proposed by Food Standards Australia New Zealand, including the need for premarket authorization and the requirement for a high level of certainty based on the totality of evidence in substantiating this type of claim. However, approaches to permitting function claims other than those for the well-established functions of known nutrients are divergent among the jurisdictions compared. Canada also differs from other jurisdictions in not establishing core nutritional criteria for foods carrying disease risk-reduction claims. A brief overview of the status in Canada of a number of disease risk-reduction claims that have been approved in the United States, based on significant scientific agreement under the Nutrition Labeling and Education Act or through authoritative statements under the Food and Drug Administration Modernization Act, is also provided.

Ctr2 is partially localized to the plasma membrane and stimulates copper uptake in COS-7 cells.

Ctr1 (copper transporter 1) mediates high-affinity copper uptake. Ctr2 (copper transporter 2) shares sequence similarity with Ctr1, yet its function in mammalian cells is poorly understood. In African green monkey kidney COS-7 cells and rat tissues, Ctr2 migrated as a predominant band of approximately 70 kDa and was most abundantly expressed in placenta and heart. A transiently expressed hCtr2-GFP (human Ctr2-green fluorescent protein) fusion protein and the endogenous Ctr2 in COS-7 cells were mainly localized to the outer membrane of cytoplasmic vesicles, but were also detected at the plasma membrane. Biotinylation of Ctr2 with the membrane-impermeant reagent sulfo-NHS-SS-biotin [sulfosuccinimidyl-2-(biotinamido)ethyl-1,3-dithiopropionate] confirmed localization at the cell surface. Cells expressing hCtr2-GFP hyperaccumulated copper when incubated in medium supplemented with 10 microM CuSO(4), whereas cells depleted of endogenous Ctr2 by siRNAs (small interfering RNAs) accumulated lower levels of copper. hCtr2-GFP expression did not affect copper efflux, suggesting that hCtr2-GFP increased cellular copper concentrations by promoting uptake at the cell surface. Kinetic analyses showed that hCtr2-GFP stimulated saturable copper uptake with a K(m) of 11.0+/-2.5 microM and a K(0.5) of 6.9+/-0.7 microM when data were fitted to a rectangular hyperbola or Hill equation respectively. Competition experiments revealed that silver completely inhibited hCtr2-GFP-dependent copper uptake, whereas zinc, iron and manganese had no effect on uptake. Furthermore, increased copper concentrations in hCtr2-GFP-expressing cells were inversely correlated with copper chaperone for Cu/Zn superoxide dismutase protein expression. Collectively, these results suggest that Ctr2 promotes copper uptake at the plasma membrane and plays a role in regulating copper levels in COS-7 cells.

Sparing effects of selenium and ascorbic acid on vitamin C and E in guinea pig tissues.

BACKGROUND: Selenium (Se), vitamin C and vitamin E function as antioxidants within the body. In this study, we investigated the effects of reduced dietary Se and L-ascorbic acid (AA) on vitamin C and alpha-tocopherol (AT) status in guinea pig tissues. METHODS: Male Hartley guinea pigs were orally dosed with a marginal amount of AA and fed a diet deficient (Se-D/MC), marginal (Se-M/MC) or normal (Se-N/MC) in Se. An additional diet group (Se-N/NC) was fed normal Se and dosed with a normal amount of AA. Guinea pigs were killed after 5 or 12 weeks on the experimental diets at 24 and 48 hours post AA dosing. RESULTS: Liver Se-dependent glutathione peroxidase activity was decreased (P < 0.05) in guinea pigs fed Se or AA restricted diets. Plasma total glutathione concentrations were unaffected (P > 0.05) by reduction in dietary Se or AA. All tissues examined showed a decrease (P < 0.05) in AA content in Se-N/MC compared to Se-N/NC guinea pigs. Kidney, testis, muscle and spleen showed a decreasing trend (P < 0.05) in AA content with decreasing Se in the diet. Dehydroascorbic acid concentrations were decreased (P < 0.05) in several tissues with reduction in dietary Se (heart and spleen) or AA (liver, heart, kidney, muscle and spleen). At week 12, combined dietary restriction of Se and AA decreased AT concentrations in most tissues. In addition, restriction of Se (liver, heart and spleen) and AA (liver, kidney and spleen) separately also reduced AT in tissues. CONCLUSION: Together, these data demonstrate sparing effects of Se and AA on vitamin C and AT in guinea pig tissues.

Dietary soy protein isolate modifies hepatic retinoic acid receptor-beta proteins and inhibits their DNA binding activity in rats.

Retinoic acid receptors (RAR) belong to the same nuclear receptor superfamily as thyroid hormone receptors (TR) that were previously shown to be modulated by dietary soy protein isolate (SPI). This study has examined the effect of dietary SPI and isoflavones (ISF) on hepatic RAR gene expression and DNA binding activity. In Expt. 1, Sprague-Dawley rats were fed diets containing 20% casein or 20% alcohol-washed SPI in the absence or presence of increasing amounts of ISF (5-1250 mg/kg diet) for 70, 190, or 310 d. In Expt. 2, weanling Sprague-Dawley rats were fed diets containing 20% casein with or without supplemental ISF (50 mg/kg diet) or increasing amounts of alcohol-washed SPI (5, 10, and 20%) for 90 d. Intake of soy proteins significantly elevated hepatic RARbeta2 protein content dose-dependently compared with a casein diet, whereas supplemental ISF had no consistent effect. Neither RARbeta protein in the other tissues measured nor the other RAR (RARalpha and RARgamma) in the liver were affected by dietary SPI, indicating a tissue and isoform-specific effect of SPI. RARbeta2 mRNA abundances were not different between dietary groups except that its expression was markedly suppressed in male rats fed SPI for 310 d. DNA binding activity of nuclear RARbeta was significantly attenuated and the isoelectric points of RARbeta2 were shifted by dietary SPI. Overall, these results show for the first time, to our knowledge, that dietary soy proteins affect hepatic RARbeta2 protein content and RARbeta DNA binding activity, which may contribute to the suppression of retinoid-induced hypertriglyceridemia by SPI as reported.

The canadian health claim for calcium, vitamin d and osteoporosis.

To provide evidence for or against allowing a health claim for calcium in Canada, we undertook a review of the current U.S. health claim for calcium and osteoporosis, and also reviewed the scientific literature published since that health claim was first proposed and reviewed by the U.S. Food and Drug Administration in 1991 and adopted in 1993. Our objectives were 1) to determine if the science behind the claim was still valid, and if so, 2) to recommend any new wording to the claim, if warranted, prior to implementation in Canada. Based on a review of the evidence (to May 2000) related to the various claim elements, the following health claim for calcium has been established in Canada: A healthy diet with adequate calcium and vitamin D, and regular physical activity, help to achieve strong bones and may reduce the risk of osteoporosis. The compositional criteria for foods bearing this claim are that the food must provide at least 200 mg calcium per serving and that the phosphorus content (excluding that provided by phytate) must be less than the calcium content.

Dietary soy protein isolate and isoflavones modulate hepatic thyroid hormone receptors in rats.

Thyroid hormone receptors (TRs) are regulators of many genes involved in cholesterol and lipid metabolism. The purpose of this study was to examine the effect of soy protein isolate (SPI) and isoflavones on hepatic TRs in rats. In Expt. 1, Sprague-Dawley rats were fed diets containing either casein or alcohol-washed SPI with or without isoflavone supplementation (5-1250 mg/kg diet) for 70, 190, and 310 d. The offspring (F1) were fed the same diets as their parents (F0). In Expt. 2, Sprague-Dawley rats were fed diets containing casein or casein plus isoflavones (50-400 mg/kg diet) for 120 d. The mRNA and protein contents of the hepatic TRs were measured by semiquantitative RT-PCR and Western blot, respectively. TRalpha1, TRalpha2, and TRbeta2 contents were not affected by SPI. However, the content of the 52-kDa TRbeta1 protein, the major isoform present in the liver, was markedly increased by dietary SPI in both sexes of F0 and F1 compared with casein. The supplemental isoflavones had no effect on TRbeta1, whereas the high doses of isoflavones (250 and 1250 mg/kg diet) reduced the hepatic TRalpha1 protein content in F1 male rats on d 28. SPI had no effect on total T3 and T4 levels. However, higher dose of supplemental isoflavones markedly increased T4 level in female rats. Overall, this study demonstrates for the first time that SPI upregulates hepatic TRbeta1 expression, and that isoflavones reduce the hepatic TRalpha1 level in young male rats. The SPI-induced TRbeta1 may play a role in mediating the hypocholesterolemic and lipid-lowering actions of soy protein.