Feasibility of recommending certain replacement or alternative fats.

Expert groups and public health authorities recommend that trans-fatty acid (TFA) intakes from industrially produced partially hydrogenated vegetable oils (PHVOs) should be less than 1% of total energy intake. The starting point for any regulatory or nonregulatory response to this recommendation is to assess the extent of the problem by determining where in the food supply TFAs are found and the amounts consumed in the population. Unfortunately, this is a particularly difficult task using traditional methods of dietary assessment inasmuch as food composition databases with TFA data are either nonexistent or incomplete in most countries. Current evidence on estimates of intake suggests there is high variability in TFA intakes and their food sources between countries. The ubiquitous presence of PHVOs in the global food supply in bakery products, deep-fried foods, snack foods, confectionery products and table spreads attests to their commercial value and convenience. However, their common use is more the result of historical convenience from an industry infrastructure developed over 50 years based on efficient, cost-effective hydrogenation of vegetable oils rather than any inherent sensory or physical superiority of the hydrogenated fats over purpose-made zero-trans fats and oils. Current global supply of appropriate zero-trans replacement fats high in cis-unsaturated fatty acids is insufficient to meet the demand if all PHVOs in the food supply were replaced. Regulatory action needs to be coordinated with supply to maximize the opportunity for health gains by replacing partially hydrogenated fats with purpose-ready zero-trans vegetable oils low in saturates and high in cis-unsaturates rather than animal fats and tropical oils high in saturated fatty acids.

Serum vitamin B12 concentrations and atrophic gastritis in older New Zealanders.

OBJECTIVE: To determine the serum vitamin B(12) status of older New Zealanders and to assess the impact of atrophic gastritis on vitamin B(12) status. DESIGN: A cross-sectional nationally representative population-based survey. METHOD: Serum vitamin B(12) concentrations were used to assess vitamin B(12) status. The presence and severity of atrophic gastritis was classified using serum pepsinogen I and II. SUBJECTS: A total of 466 noninstitutionalized urban and rural dwelling New Zealanders aged 65 y or older who participated in the 1997 National Nutrition Survey. RESULTS: The prevalence of deficient (<148 pmol/l) and marginal (148-221 pmol/l) serum vitamin B(12) concentrations was 12 and 28%, respectively. The prevalence of atrophic gastritis was 6.7% (severe 3.1%, mild-moderate 3.6%). While atrophic gastritis increased the relative risk (RR, 95% CI) of having a deficient or marginal serum vitamin B(12) concentration by 21-fold (6-67) and five-fold (1-17), respectively, those who had atrophic gastritis made up only 33 and 6% of the participants with deficient or marginal serum vitamin B(12) concentrations. An intake of vitamin B(12) from food that exceeded the recommended dietary allowance (2.4 mug/day) did not protect against deficient (RR 0.5; 95% CI: 0.2, 1.2) or marginal (RR 0.9; 95% CI: 0.5, 1.7) serum vitamin B(12) status. Vitamin B(12) supplement users had a reduced risk of having deficient and marginal vitamin B(12) status (RR 0.3; 95% CI: 0.1, 0.8). CONCLUSIONS: There is a relatively high prevalence of deficient and marginal serum vitamin B(12) concentrations among older New Zealanders. However, the prevalence of atrophic gastritis was low in the New Zealand elderly compared with other surveys. Although atrophic gastritis was a risk factor for low vitamin B(12) status, it did not fully explain the prevalence of low serum vitamin B(12).

Effects of once-a-week or daily folic acid supplementation on red blood cell folate concentrations in women.

OBJECTIVE: Our aim was to determine if a once-a-week folic acid supplement increases women's red blood cell folate to concentrations (>905 nmol/l) that are associated with a low risk of bearing a child with a neural tube defect. DESIGN: Randomized control trial. SETTING: General community. SUBJECTS: In total, 114 nonpregnant women (18-40 y) volunteers, with red blood cell folate concentrations between 295 and 905 nmol/l at screening. INTERVENTION: Women were randomized to receive a once-a-week 2800 microg folic acid supplement, a daily 400 microg folic acid supplement or a daily placebo for 12 weeks. RESULTS: The mean (95% CI) red blood cell folate concentrations increased during the 12-week intervention from 608 (553-668) to 900 (828-978) in the weekly folic acid group (P<0.05) and from 615 (560-677) to 1053 (957-1158) nmol/l in the daily group (P<0.05) during the trial. At week 12, 49% of women ingesting the weekly folic acid supplement had red blood cell folate concentrations greater than 905 nmol/l compared to 74% of women ingesting the daily supplement. CONCLUSION: A once-a-week 2800 microg folic acid supplement can increase women's red blood cell folate to concentrations associated with a reduced risk of bearing a child with a neural tube defect, but is less effective than a 400 microg daily supplement. Use of a weekly folic acid supplement over at least 12 weeks before conception by women of child-bearing age may prevent neural tube defects. FUNDING: The Otago Medical Research Foundation (Laurenson Award). Healtheries (New Zealand) provided the supplements.

Maximal response to a plasma cholesterol-lowering diet is achieved within two weeks.

BACKGROUND AND AIM: Replacing saturated fat with polyunsaturated fat reduces plasma cholesterol concentrations; however, it has not been well documented how rapidly the decline occurs nor how long is required to reach the maximum cholesterol-lowering effect. The aim of the present study was to determine the time course of change in plasma cholesterol concentrations when participants adopt a lipid-lowering diet. METHODS AND RESULTS: Participants (n = 19) were asked to follow for 19 days a diet high in saturated fat and then crossed over--without washout--for 19 days to a diet high in n-6 polyunsaturated fat. Participants were asked to maintain a total fat intake of 30-33% of total energy on both diets. Energy and nutrient intakes were assessed by self-reported food records covering 3 days. Plasma total cholesterol concentrations were measured on days 0, 1, 2, 5, 8, 12, and 19 of the n-6 polyunsaturated fat rich diet. Mean (95% CI) plasma total cholesterol concentration declined from 5.10 mmol/L (4.77, 5.46) at day 0 to 4.25 mmol/L (3.83, 4.67) on day 12 and remained unchanged at 4.23 mmol/L (3.85, 4.61) on day 19. A statistically significant decrease in plasma cholesterol concentration was achieved on day 2 of the intervention; by day 5, 59% (0.51 mmol/L) of the maximum reduction (0.87 mmol/L) had been reached. CONCLUSIONS: Adopting a lipid lowering diet initiates an immediate decline in plasma cholesterol concentration, the full effect of which is achieved within two weeks.

Can dietary treatment of non-anemic iron deficiency improve iron status?

OBJECTIVE: To investigate the efficacy of, first, a dietary regimen involving increased consumption of iron-rich foods and enhancers of iron absorption and decreased consumption of inhibitors of iron absorption and, second, a low dose iron chelate iron supplement, for increasing iron stores in young adult New Zealand women with mild iron deficiency (MID). METHODS: The study was a 16 week randomized placebo-controlled intervention. Seventy-five women aged 18 to 40 years with MID (serum ferritin < 20 microg/L and hemoglobin > or = 120 g/L) were assigned to one of three groups: Placebo, Supplement (50 mg iron/day as amino acid chelate) or Diet. Participants in the Diet Group were given individual dietary counseling to increase the intake and bioavailability of dietary iron. Dietary changes were monitored by a previously validated computer-administered iron food frequency questionnaire. RESULTS: Diet Group members significantly increased their intake of flesh foods, heme iron, vitamin C and foods cooked using cast-iron cookware and significantly decreased their phytate and calcium intakes. Serum ferritin increased in the Supplement and Diet Groups by 59% (p=0.001) and 26% (p=0.068), respectively, in comparison to the Placebo Group. The serum transferrin receptor:serum ferritin ratio decreased by 51% in the Supplement Group (p=0.001), and there was a non-significant decrease of 22% (p=0.1232) in the Diet Group. CONCLUSIONS: This study is the first, to our knowledge, to demonstrate that an intensive dietary program has the potential to improve the iron status of women with iron deficiency.

The effect of replacing dietary saturated fat with polyunsaturated or monounsaturated fat on plasma lipids in free-living young adults.

OBJECTIVE: To examine, in free-living adults eating self-selected diets, the effects on plasma cholesterol of substituting saturated fat rich foods with either n-6 polyunsaturated or monounsaturated fat rich foods while at the same time adhering to a total fat intake of 30-33% of dietary energy. DESIGN: Two randomised crossover trials. SETTING: General community. SUBJECTS: Volunteer sample of healthy free-living nutrition students at the University of Otago. Trial I, n=29; and trial II, n=42. INTERVENTIONS: In trials I and II participants were asked to follow for 2(1/2) weeks a diet high in saturated fat yet with a total fat content that conformed to nutrition recommendations (30-33% energy). During the 2(1/2) week comparison diet, saturated fat rich foods were replaced with foods rich in n-6 polyunsaturated fats (trial I) whereas in trial II the replacement foods were rich in monounsaturated fats. Participants were asked to maintain a total fat intake of 30-33% of energy on all diets. MAIN OUTCOME MEASURES: Energy and nutrient intakes, plasma triglyceride fatty acids, and plasma cholesterol. RESULTS: When replacing saturated fat with either n-6 polyunsaturated fat or monounsaturated fat, total fat intakes decreased by 2.9% energy and 5.1% energy, respectively. Replacing saturated fat with n-6 polyunsaturated fat (trial I) lowered plasma total cholesterol by 19% [from 4.87 (0.88) to 3.94 (0.92) mmol/l, mean (s.d.)], low density lipoprotein cholesterol by 22% [from 2.87 (0.75) to 2.24 (0.67) mmol/l], and high density lipoprotein cholesterol by 14% [from 1.39 (0.36) to 1.19 (0.34) mmol/l], whereas replacing saturated fat with monounsaturated fat (trial II) decreased total cholesterol by 12%, low density lipoprotein cholesterol by 15%, and high density lipoprotein cholesterol by 4%, respectively. The change in the ratio of total to high density lipoprotein cholesterol was similar during trial I and trial II. CONCLUSIONS: Young adults are very responsive to dietary-induced changes in plasma cholesterol even when an isocaloric replacement of saturated fat with n-6 polyunsaturated or monounsaturated fat is not achieved. Replacing saturated fat with either n-6 polyunsaturated or monounsaturated fat is equally efficacious at reducing the total to high density lipoprotein cholesterol ratio. SPONSORSHIP: University of Otago, Meadow Lea Ltd.

Comparison of a vitamin E-rich diet and supplemental vitamin E on measures of vitamin E status and lipoprotein profile.

OBJECTIVE: To determine whether dietary modification rather than use of supplements can raise indices of vitamin E status to potentially cardioprotective levels. DESIGN: Eight week randomised controlled trial with parallel treatments to compare increased use of vitamin E-rich foods, supplementation with 200 IU of vitamin E, and a placebo. SETTING: Dunedin, New Zealand. SUBJECTS: Ninety subjects were recruited, of whom 82 non-smoking, free-living individuals aged 22-72 y with plasma cholesterol <7.5 mmol/l completed the trial. MAIN OUTCOME MEASURES: Dietary intakes, plasma alpha tocopherol, plasma alpha tocopherol/cholesterol ratio and lipoprotein cholesterol. RESULTS: Consumption of an additional 12 mg of vitamin E (alpha tocopherol equivalents) from dietary sources was primarily achieved through the replacement of saturated fat-rich foods with unsaturated fats rich in vitamin E, nuts and vegetables. This resulted in a 3.4 micromol/l increase in plasma alpha tocopherol at week 6 (95% CI 1.6-5.3), and 0.9 micromol/mmol in plasma alpha tocopherol/cholesterol at weeks 4 and 6 (95% CI 0.3-1.4 and 0.4-1.4, respectively) when compared with the placebo group. In the supplement group, plasma alpha tocopherol and plasma alpha tocopherol/cholesterol were significantly increased within 2 weeks and remained so throughout the 8 week intervention. CONCLUSION: Increasing dietary vitamin E intake can increase plasma alpha tocopherol levels, although factors other than dietary intake are also important determinants. The extent of dietary modification required to achieve potentially cardioprotective levels of plasma alpha tocopherol is difficult in practice. SPONSORSHIP: The study was supported through the Otago Medical Research Foundation Laurenson Award.

The role of blood loss and diet in the aetiology of mild iron deficiency in premenopausal adult New Zealand women.

OBJECTIVE: To investigate the role of blood loss and diet in the aetiology of mild iron deficiency (MID) in premenopausal New Zealand women. Mild iron deficiency was defined as low, but not necessarily exhausted, iron stores (i.e. serum ferritin <20 microg/L) in the absence of anaemia (i.e. haemoglobin > or =120 g/L). DESIGN: Cross-sectional study of a volunteer sample of premenopausal adult women. Information on habitual dietary intakes (using a specially designed and validated computerised iron food frequency questionnaire), health and demographic status, sources of blood loss (including menstrual blood loss estimated using a validated menstrual recall method), contraceptive use, height and weight, haemoglobin, serum ferritin and C-reactive protein were collected. SETTING: Dunedin, New Zealand during 1996/1997. PARTICIPANTS: Three hundred and eighty-four women aged 18-40 years. RESULTS: The characteristics that were associated with an increased risk of MID were: low meat/fish/poultry intake, high menstrual blood loss, recent blood donation, nose bleeds, and low body mass index. The protective factors included shorter duration of menstrual bleeding, and multivitamin-mineral supplement use in the past year. CONCLUSIONS: There are a number of potentially modifiable factors that appear to influence risk of MID. Women with low menstrual blood loss may be able to decrease their risk of MID by increasing their meat/fish/poultry intake, while those with a higher menstrual blood loss may be able to decrease their risk by decreasing their menstrual blood loss, perhaps by changing their method of contraception. Women should be encouraged to maintain a healthy body weight, and those who choose to donate blood, or who experience nose bleeds, should have their iron stores monitored.

Men who consume vegetable oils rich in monounsaturated fat: their dietary patterns and risk of prostate cancer (New Zealand).

OBJECTIVES: To investigate (i) dietary patterns associated with consumption of vegetable oils rich in monounsaturated fatty acids (MUFA), and (ii) the risk of prostate cancer associated with consumption of these oils. METHODS: A population-based case-control study was conducted in Auckland, New Zealand, involving 317 prostate cancer cases and 480 controls. A food-frequency questionnaire was used to collect data concerning consumption of MUFA-rich vegetable oils (including olive oil, canola or peanut oil) and other dietary variables. Biomarkers for fatty acids were measured in erythrocytes. RESULTS: The group of participants who reported regular consumption of greater than 5.5 ml of MUFA-rich vegetable oils per day had a diet relatively high in monounsaturated fat, vegetables, lycopene, vitamin E, selenium, and n-3 fish oils. Increasing levels of MUFA-rich vegetable oil intake were associated with a progressive reduction in prostate cancer risk (multivariate relative risk = 0.5; 95% confidence interval 0.3-0.9; > 5.5 ml per day vs. nonconsumption, p trend = 0.005), and similar trends were observed across all strata of socioeconomic status. Prostate cancer risk was not associated with intake of total MUFA or the major animal food sources of MUFA. CONCLUSION: This finding may be explained by the protective effect of an associated dietary pattern high in antioxidants and fish oils, an independent protective effect of MUFA-rich vegetable oils unrelated to the MUFA component, or a combination of these factors.

The relative validity of a computerized food frequency questionnaire for estimating intake of dietary iron and its absorption modifiers.

OBJECTIVE: To determine the relative validity of an iron food frequency questionnaire (iron FFQ) designed to assess intakes of dietary iron and its absorption modifiers. DESIGN: A computer-administered food frequency questionnaire was designed to estimate intake of total, non-haem, haem and meat iron as well as dietary components which influence iron absorption (vitamin C, phytate, calcium, grammes of meat/fish/poultry, tea and coffee) in women consuming a Western diet. The relative validity of the iron FFQ was assessed by comparing its results with those from weighed diet records collected over 11 days. SETTING: Dunedin, New Zealand. PARTICIPANTS: Forty-nine women aged 19-31 y attending the University of Otago. RESULTS: There was good agreement between the iron FFQ and the weighed diet records for median intakes of total iron, non-haem iron, calcium, tea and coffee. For dietary component intakes, correlations between the two methods ranged from 0.39 (for vitamin C) to 0.87 (for coffee) with 0.52 for total iron, and 0.61 for haem iron. In cross-classification with the weighed diet record, the iron FFQ correctly classified between 22% (for vitamin C) and 51% (for phytate) of participants into the same quartile. Actual values for surrogate categories indicated that the questionnaire can clearly differentiate between low and high intakes of all the dietary components assessed. The questionnaire also showed an acceptable level of agreement between repeat administrations (eg a correlation for total iron of 0.65). CONCLUSIONS: The iron FFQ is appropriate for assessing group intakes of total iron, and iron absorption modifiers, in population studies to assess the aetiology and treatment of iron deficiency states in adult women consuming a Western diet. SPONSORSHIP: This research was supported (in part) by a grant from the Health Research Council of New Zealand.

Physiological effects of a fish oil supplement on captive juvenile tuatara (Sphenodon punctatus).

Tuatara (Sphenodon, Order Sphenodontia) are rare New Zealand reptiles whose conservation involves captive breeding. Wild tuatara eat seabirds, which contain high levels of the long-chain n-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These fatty acids are absent from the captive diet, and consequently, plasma fatty acid composition of wild and captive tuatara differs. This study investigated the effects of incorporating EPA and DHA into the diet of captive juvenile tuatara (Sphenodon punctatus) in an attempt to replicate the plasma fatty acid composition of wild tuatara. Tuatara receiving a fish oil supplement containing EPA and DHA showed overall changes in their plasma fatty acid composition. Phospholipid EPA and DHA increased markedly, reaching 10.0% and 5.9 mol%, respectively, by 18 mo (cf.

Variation in plasma cholesterol response to dietary change.

BACKGROUND AND AIMS: Previous studies have suggested that some individuals show an appreciably larger change in total cholesterol in response to dietary change (hyper-responders) than others (minimal responders), and also that some people are more likely to respond consistently. We have examined the role of individual dietary compliance in determining total cholesterol response to changes in the nature of dietary fat. METHODS AND RESULTS: Participants completed a randomised double dietary crossover trial with a diet high in saturated fat and a diet high in polyunsaturated fat. Each period continued for four weeks without washouts. Plasma lipoproteins were measured at the end of each period. Dietary compliance was assessed by change in the reported polyunsaturated:saturated fat ratio calculated from three-day diet records, and change in polyunsaturated fat intake, determined by change in plasma triglyceride linoleate. A wide range of individual responses was observed with no evidence of two distinct populations of hyper- and minimal responders. Variation in response to the three crossovers appeared to be due mainly to variation in compliance. CONCLUSIONS: The results of this study do not support earlier suggestions of two separate populations of hyper and minimal responders to change in the nature of dietary fat, rather there is a graded range of response. In a free-living population, the extent to which individuals comply with dietary advice varies considerably and this contributes to the magnitude of cholesterol response as well as consistency on repeated dietary challenges.

The alkenylacyl class of ethanolamine phospholipid represents a major form of eicosapentaenoic acid (EPA)-containing phospholipid in the platelets of human subjects consuming a fish oil concentrate.

A quantitative assessment was made of the distribution of arachidonic acid (AA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) among the individual sub-classes (diacyl, alkylacyl, alkenylacyl) of the various platelet phospholipids of human subjects consuming a fish oil concentrate (as MaxEPA) enriched in EPA plus DHA. This work was of interest since dietary fish oils provide for a pronounced enrichment of platelet phospholipid in EPA as well as DPA plus DHA to a lesser extent while reducing AA-phospholipid and platelet reactivity. After 42 days of MaxEPA supplementation (providing 3.6 g EPA and 2.4 g DHA per day), the majority of the mass of all four polyunsaturated fatty acids in the choline-containing phospholipid (PC) was found in the diacyl species (76-87% of total PC). In contrast, twice as much of the EPA in the ethanolamine-containing phospholipid (PE) resided in the alkenylacyl species (62.7% of total PE) relative to the diacyl species (32.3%) with minor amounts in the alkylacyl fraction (5.1%). The major single reservoir of total EPA-containing phospholipid was the alkenylacyl PE (38.2% of total) followed by diacyl PC (27.8%), diacyl PE (19.6%), with progressively lesser amounts in the alkylacyl PC, alkylacyl PE, diacyl PS (phosphatidylserine), alkenylacyl PC, and diacyl PI (phosphatidylinositol) at 6.7, 3.1, 2.3, 1.4, and 0.8% of the total mass, respectively. In contrast, only 27.1% of the total mass of AA-phospholipid was represented by the alkenylacyl PE with the bulk of the remainder being distributed in the diacyl species of PE, PC, PI, and PS.(ABSTRACT TRUNCATED AT 250 WORDS)

Alterations in molecular species of cholesterol esters formed via plasma lecithin-cholesterol acyltransferase in human subjects consuming fish oil.

The influence of a dietary supplement of n-3 polyunsaturated fatty acids containing eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) on the molecular species of cholesteryl esters (CE) formed via the plasma lecithin (phosphatidylcholine)-cholesterol acyltransferase (LCAT; EC 2.3.1.43) reaction was evaluated. For this purpose, one group of eight subjects received an encapsulated fish lipid concentrate (MaxEPA) and another group of eight volunteers in the control group received encapsulated olive oil for 22 days. Plasma lipid profiles and fatty acid compositions of plasma phosphatidylcholine (PC) and CE were measured at day 0 and day 22 in all subjects. A decrease in plasma triglyceride (by 34%) and a moderate rise in high-density lipoprotein (HDL)-cholesterol (by 13%) was observed in the MaxEPA group. For characterization of the plasma LCAT-derived reaction products formed in vitro, [14C]cholesterol was used as the substrate and the newly formed molecular species of [14C]CE were separated by argentation thin-layer chromatography. Marked shifts were found in the abundance of the various classes of LCAT-derived products in the MaxEPA group whereas no significant changes were observed in the controls. The proportion of the [14C]CE as pentaenoic (EPA) species rose by 9-fold (from 1.5% at day 0 to 14.4% at day 22) as the dienoic (linoleate) species fell (from 50.6 to 39.2%); a moderate rise in the hexaenoic (DHA) species (from 1.7 to 2.4%) with no significant change in the tetraenoic (arachidonate) (AA) species was observed. The LCAT results were in the order of the observed shifts in the fatty acid patterns of the plasma CE.(ABSTRACT TRUNCATED AT 250 WORDS)