Helen Rasmussen

Immunologic effects of national cholesterol education panel step-2 diets with and without fish-derived N-3 fatty acid enrichment.

Reductions in dietary fat, saturated fat, and cholesterol have been recommended to reduce the risk of heart disease in our society. The effects of these modifications on human cytokine production and immune responses have not been well studied. 22 subjects > 40 yr of age were fed a diet approximating that of the current American (14.1% of calories as saturated fatty acids, [SFA], 14.5% monounsaturated fatty acids [MUFA], 6.1% [n-6] polyunsaturated fatty acids [PUFA], 0.8% [n-3] PUFA, and 147 mg cholesterol/1,000 calories) for 6 wk, after which time they consumed (11 in each group) one of the two low-fat, low-cholesterol, high-PUFA diets based on National Cholesterol Education Panel (NCEP) Step 2 recommendations (4.0-4.5% SFA, 10.8-11.6% MUFA, 10.3-10.5% PUFA, 45-61 mg cholesterol/1,000 calories) for 24 wk. One of the NCEP Step 2 diets was enriched in fish-derived (n-3) PUFA (low-fat, high-fish: 0.54% or 1.23 g/d eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA] [121-188 g fish/d]) and the other low in fish-derived (n-3) PUFA (low-fat, low-fish [0.13% or 0.27 g/d EPA and DHA] [33 g fish/d]). Measurements of in vivo and in vitro indexes of immune responses were taken after each dietary period. Long-term feeding of low-fat, low-fish diet enriched in plant-derived PUFA increased blood mononuclear cell mitogenic response to the T cell mitogen Con A, IL-1 beta, and TNF production and had no effect on delayed-type hypersensitivity skin response, IL-6, GM-CSF, or PGE2 production. In contrast, the low-fat, high-fish diet significantly decreased the percentage of helper T cells whereas the percentage of suppressor T cells increased. Mitogenic responses to Con A and delayed-type hypersensitivity skin response as well as the production of cytokines IL-1 beta, TNF, and IL-6 by mononuclear cells were significantly reduced after the consumption of the low-fat, high-fish diet (24, 40, 45, 35, and 34%, respectively; P < 0.05 by two-tailed Students t test except for IL-1 beta and TNF, which is by one-tailed t test). Our data are consistent with the concept that the NCEP Step 2 diet that is high in fish significantly decreases various parameters of the immune response in contrast to this diet when it is low in fish. Such alterations may be beneficial for the prevention and treatment of atherosclerotic and inflammatory diseases but may be detrimental with regard to host defense against invading pathogens.

Lipoprotein Response to Diets High in Soy or Animal Protein With and Without Isoflavones in Moderately Hypercholesterolemic Subjects

Objective—The objective of this study was to assess the independent effect of soy relative to common sources of animal protein and soy-derived isoflavones on blood lipids. Methods and Results—Forty-two subjects with LDL cholesterol levels ≥3.36 mmol/L were fed each of four diets in randomized order for 6 weeks per phase. Diets contained a minimum of 25 g animal protein or isolated soy protein/4.2 MJ, with each containing trace amounts or 50 mg of isoflavones/4.2 MJ. Soy protein had a modest effect on total, LDL and HDL cholesterol, and triglyceride concentrations (−2%, P =0.017; −2%, P =0.042; +3%;P =0.034, −11%, P <0.001, respectively). Soy protein had no significant effect on plasma lipids in individuals with LDL cholesterol <4.14 mmol/L and significantly reduced total and LDL cholesterol and triglyceride concentrations in individuals with LDL cholesterol ≥4.14 mmol/L (−4%, P =0.001; −5%, P =0.003; −15%, P <0.001, respectively). No significant effect of isoflavones on plasma lipid levels was observed either constituent to the soy protein or supplemental to the animal protein. Conclusions—Although potentially helpful when used to displace products containing animal fat from the diet, the regular intake of relatively high levels of soy protein (>50 g/day) had only a modest effect on blood cholesterol levels and only in subjects with elevated LDL cholesterol levels (≥4.14 mmol/L). Soy-derived isoflavones had no significant effect.

Efficacy of a National Cholesterol Education Program Step 2 Diet in Normolipidemic and Hypercholesterolemic Middle-Aged and Elderly Men and Women

We tested the effects of a National Cholesterol Education Program (NCEP) Step 2 diet (30% of calories or less as total fat, less than 7% saturated fat, and less than 200 mg cholesterol per day) on plasma lipid levels in normocholesterolemic and hypercholesterolemic middle-aged and elderly men and women. Thirty-two subjects were studied. Eight normolipidemic subjects (6 men and 2 women, mean age 56 +/- 13 years) with LDL cholesterol levels of less than 4.14 mmol/L (160 mg/dL) were given a baseline diet similar in composition to the diet currently consumed in the United States (35% of calories as total fat and 14% as saturated fat, with 147 mg cholesterol per 1000 kcal) for 6 weeks. Subjects were then placed on an NCEP Step 2 diet (26% total fat, 4% saturated fat, 45 mg cholesterol per 1000 kcal) for 24 weeks. In addition, 24 subjects (12 men and 12 women, mean age 62 +/- 12 years) with moderate hypercholesterolemia (LDL cholesterol levels of 4.14 mmol/L or above) were given a baseline diet for 6 weeks and then the NCEP Step 2 diet for 6 weeks. Energy intakes were adjusted to keep body weight constant throughout the study. In both normolipidemic and hypercholesterolemic subjects, consumption of the NCEP Step 2 diet was associated with significant changes in levels of total cholesterol (-20% and -16%, respectively), LDL cholesterol (-21% and -18%, respectively), and HDL cholesterol (-16% and -15%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment with Potassium Bicarbonate Lowers Calcium Excretion and Bone Resorption in Older Men and Women

CONTEXT Bicarbonate has been implicated in bone health in older subjects on acid-producing diets in short-term studies. OBJECTIVE The objective of this study was to determine the effects of potassium bicarbonate and its components on changes in bone resorption and calcium excretion over 3 months in older men and women. DESIGN, PARTICIPANTS, AND INTERVENTION In this double-blind, controlled trial, 171 men and women age 50 and older were randomized to receive placebo or 67.5 mmol/d of potassium bicarbonate, sodium bicarbonate, or potassium chloride for 3 months. All subjects received calcium (600 mg of calcium as triphosphate) and 525 IU of vitamin D(3) daily. MAIN OUTCOME MEASURES Twenty-four-hour urinary N-telopeptide and calcium were measured at entry and after 3 months. Changes in these measures were compared across treatment groups in the 162 participants included in the analyses. RESULTS Bicarbonate affected the study outcomes, whereas potassium did not; the two bicarbonate groups and the two no bicarbonate groups were therefore combined. Subjects taking bicarbonate had significant reductions in urinary N-telopeptide and calcium excretion, when compared with subjects taking no bicarbonate (both before and after adjustment for baseline laboratory value, sex, and changes in urinary sodium and potassium; P = 0.001 for both, adjusted). Potassium supplementation did not significantly affect N-telopeptide or calcium excretion. CONCLUSIONS Bicarbonate, but not potassium, had a favorable effect on bone resorption and calcium excretion. This suggests that increasing the alkali content of the diet may attenuate bone loss in healthy older adults.

Potassium Bicarbonate Attenuates the Urinary Nitrogen Excretion That Accompanies an Increase in Dietary Protein and May Promote Calcium Absorption

CONTEXT Protein is an essential component of muscle and bone. However, the acidic byproducts of protein metabolism may have a negative impact on the musculoskeletal system, particularly in older individuals with declining renal function. OBJECTIVE We sought to determine whether adding an alkaline salt, potassium bicarbonate (KHCO3), allows protein to have a more favorable net impact on intermediary indices of muscle and bone conservation than it does in the usual acidic environment. DESIGN We conducted a 41-d randomized, placebo-controlled, double-blind study of KHCO3 or placebo with a 16-d phase-in and two successive 10-d metabolic diets containing low (0.5 g/kg) or high (1.5 g/kg) protein in random order with a 5-d washout between diets. SETTING The study was conducted in a metabolic research unit. PARTICIPANTS Nineteen healthy subjects ages 54-82 yr participated. INTERVENTION KHCO3 (up to 90 mmol/d) or placebo was administered for 41 d. MAIN OUTCOME MEASURES We measured 24-h urinary nitrogen excretion, IGF-I, 24-h urinary calcium excretion, and fractional calcium absorption. RESULTS KHCO3 reduced the rise in urinary nitrogen excretion that accompanied an increase in protein intake (P = 0.015) and was associated with higher IGF-I levels on the low-protein diet (P = 0.027) with a similar trend on the high-protein diet (P = 0.050). KHCO3 was also associated with higher fractional calcium absorption on the low-protein diet (P = 0.041) with a similar trend on the high-protein diet (P = 0.064). CONCLUSIONS In older adults, KHCO3 attenuates the protein-induced rise in urinary nitrogen excretion, and this may be mediated by IGF-I. KHCO3 may also promote calcium absorption independent of the dietary protein content.

The effects of a multivitamin/mineral supplement on micronutrient status, antioxidant capacity and cytokine production in healthy older adults consuming a fortified diet.

Background: Inadequate micronutrient intake among older adults is common despite the increased prevalence of fortified/enriched foods in the American diet. Although many older adults take multivitamin supplements in an effort to compensate, studies examining the benefits of this behavior are absent. Objective: To determine whether a daily multivitamin/mineral supplement can improve micronutrient status, plasma antioxidant capacity and cytokine production in healthy, free-living older adults already consuming a fortified diet. Methods: An eight-week double-blind, placebo-controlled clinical trial among 80 adults aged 50 to 87 years (mean=66.5±8.6 years). Results: Multivitamin treatment significantly increased (p<0.01, compared to placebo) plasma concentrations of vitamins D (77 to 100 nmol/L), E (27 to 32 μmol/L), pyridoxal phosphate (55.1 to 75.2 nmol/L), folate (23 to 33 nmol/L), B12 (286 to 326 pmol/L)), C (55 to 71 μmol/L), and improved the riboflavin activity coefficient (1.23 to 1.15), but not vitamins A and thiamin. The multivitamin reduced the prevalence of suboptimal plasma levels of vitamins E (p=0.003), B12 (p=0.004), and C (p=0.08). Neither glutathione peroxidase activity nor antioxidant capacity (ORAC) were affected. No changes were observed in interleukin−2, −6 or −10 and prostaglandin E2, proxy measures of immune responses. Conclusions: Supplementation with a multivitamin formulated at about 100% Daily Value can decrease the prevalence of suboptimal vitamin status in older adults and improve their micronutrient status to levels associated with reduced risk for several chronic diseases.

Intake of Lutein and Zeaxanthin Differ with Age, Sex, and Ethnicity

Lutein and zeaxanthin are carotenoids that are selectively taken up into the macula of the eye, where they may protect against development of age-related macular degeneration. Accurate assessment of their intakes is important in the understanding of their individual roles in eye health. Current dietary databases lack the appropriate information to ascertain valid dietary intakes of these individual nutrients. The purpose of this research is to determine intakes of lutein and zeaxanthin separately in the National Health and Nutrition Examination Survey (NHANES) 2003-2004. The top major food sources for lutein and zeaxanthin intake in NHANES 2003-2004 were analyzed for lutein and zeaxanthin by high-performance liquid chromatography from June to August 2006. Results were applied to dietary data from 8,525 participants in NHANES 2003-2004. Lutein and zeaxanthin food contents were separated into lutein and zeaxanthin in the nutrient database. Mean intakes from two nonconsecutive 24-hour recalls were grouped into food groups based on nutrient composition; these were matched to the new database, and lutein and zeaxanthin intakes were calculated separately. Among all age groups, both sexes, and all ethnicities, intakes of lutein were greater than of zeaxanthin. Relative intake of zeaxanthin to lutein decreased with age, with zeaxanthin to lutein ratios lower in females. Zeaxanthin to lutein ratios in Mexican Americans was considerably greater than other ethnicities (other Hispanics, non-Hispanic white, non-Hispanic black, other races). Lower zeaxanthin to lutein ratios were measured in groups at risk for age-related macular degeneration (eg, older participants, females). Our findings suggest that the relative intake of lutein and zeaxanthin may be important to age-related macular degeneration risk. Future studies are needed to assess the individual associations of lutein and zeaxanthin in eye health.

Comparative effects of oral aromatic and branched-chain amino acids on urine calcium excretion in humans

SummaryIn 30 adults, increasing intake of aromatic amino acids increased calcium excretion and serum IGF-1, but not indices of bone turnover, when compared with similar increases in intake of branched-chain amino acids. The mechanisms involved are not certain but these findings suggest a role for the calcium sensor receptor.IntroductionIn contrast to branched-chain amino acids (BCAAs), aromatic amino acids (AAAs) bind to the calcium sensing receptor (CaR) and thus have an increased potential to affect calcium homeostasis. In this study we compare the effects of increased intake of AAAs versus BCAAs on calcium excretion, serum IGF-1, markers of bone turnover, and 4-hr calcium excretion after an oral calcium load.MethodsAfter two weeks on low-protein metabolic diets, 30 healthy subjects were randomized to a fivefold increase in intake of AAAs or BCAAs for two weeks. Changes in calcium excretion and other measures were compared in the two groups.ResultsWith the increase in amino acid intake, 24-hr calcium excretion (P = 0.027), IGF-1 (P = 0.022), and 4-hr calcium excretion after an oral load (P = 0.023) increased significantly in the AAA relative to the BCAA group. Group changes in turnover markers did not differ significantly.ConclusionIn comparison with BCAAs, AAAs promoted calcium excretion. The calciuria does not appear to result from increases in bone resorption and may occur by increasing calcium absorption. The AAAs also increased circulating levels of IGF-1. Collectively these findings raise the possibility that AAAs may selectively influence calcium homeostasis through their interactions with the CaR.

Benefits and Costs of Medical Nutrition Therapy by Registered Dietitians for Patients With Hypercholesterolemia

Abstract The Massachusetts Dietetic Association implemented a statewide retrospective quality assurance audit to determine the effectiveness and cost of medical nutrition therapy in patients with hypercholesterolemia (>5.20mmol/L). Hypercholesterolemia is a major risk factor for coronary artery disease (CAD). Data were collected at 23 sites from 285 outpatients seen by a registered dietitian for a minimum of two visits. Patients taking lipid-lowering medications were excluded. Of the 285 patients, 108 (38%) were men and 177 (62%) were women. The mean age was 51.4 years (range=22 to 79 years). Results showed that the mean reduction in serum cholesterol level was 8.6%, which translates to a decrease of approximately 17.2% in risk of CAD. Forty-five percent of the total population showed an 11% or greater reduction in serum cholesterol levels. Reduction in serum cholesterol levels correlated with increased time spent with a dietitian ( r =.188, P J Am Diet Assoc. 1995; 95:1041-1043 .

Oxidative stress and antioxidant status in older adults with early cataract.

PurposeOxidative stress and antioxidant status were determined in forty healthy men and postmenopausal women aged 50–70 years (F25, M15), who underwent concurrent eye examinations.MethodsBlood samples were collected for analysing major well-known antioxidants by HPLC systems with UV and ECD detectors, total antioxidant performance using a fluorometry, lipid peroxidation determined by malondialdehyde using a HPLC system with a fluorescent detector and by total hydroxyoctadecadienoic acid (HODE) and F2-isoprotanes (8-iso-PGF2α) using GC-MS.ResultsTwenty-seven (F17, M10) of the 40 subjects were diagnosed to have early cataracts at the onset of the study, which were regarded as age appropriate lens opacities. There was no significant difference in plasma major antioxidants, total antioxidant performance, and lipid peroxidation determined by malondialdehyde as well as 8-iso-PGF2α between the groups with and without early cataract. However, isomers of 9- and 13-(Z,E)-HODE levels were significantly higher in subjects with early cataract as compared with those of non-cataract subjects (P<0.05).ConclusionOur data suggest that subjects with early cataract are under increased systemic oxidative stress, which can be identified by a sensitive biomarker of lipid peroxidation, such as isomers of HODE.