(1/4907) Dietary intake and practices in the Hong Kong Chinese population.

OBJECTIVES: To examine dietary intake and practices of the adult Hong Kong Chinese population to provide a basis for future public health recommendations with regard to prevention of certain chronic diseases such as cardiovascular disease, hypertension, and osteoporosis. PARTICIPANTS: Age and sex stratified random sample of the Hong Kong Chinese population aged 25 to 74 years (500 men, 510 women). METHOD: A food frequency method over a one week period was used for nutrient quantification, and a separate questionnaire was used for assessment of dietary habits. Information was obtained by interview. RESULTS: Men had higher intakes of energy and higher nutrient density of vitamin D, monounsaturated fatty acids and cholesterol, but lower nutrient density of protein, many vitamins, calcium, iron, copper, and polyunsaturated fatty acids. There was an age related decrease in energy intake and other nutrients except for vitamin C, sodium, potassium, and percentage of total calorie from carbohydrate, which all increased with age. Approximately 50% of the population had a cholesterol intake of < or = 300 mg; 60% had a fat intake < or = 30% of total energy; and 85% had a percentage of energy from saturated fats < or = 10%; criteria considered desirable for cardiovascular health. Seventy eight per cent of the population had sodium intake values in the range shown to be associated with the age related rise in blood pressure with age. Mean calcium intake was lower than the FAO/WHO recommendations. The awareness of the value of wholemeal bread and polyunsaturated fat spreads was lower in this population compared with that in Australia. There was a marked difference in types of cooking oil compared with Singaporeans, the latter using more coconut/palm/mixed vegetable oils. CONCLUSION: Although the current intake pattern for cardiovascular health for fat, saturated fatty acid, and cholesterol fall within the recommended range for over 50% of the population, follow up surveys to monitor the pattern would be needed. Decreasing salt consumption, increasing calcium intake, and increasing the awareness of the health value of fibre may all be beneficial in the context of chronic disease prevention.  (+info)

(2/4907) Prior protein intake may affect phenylalanine kinetics measured in healthy adult volunteers consuming 1 g protein. kg-1. d-1.

Study of the amino acid metabolism of vulnerable groups, such as pregnant women, children and patients, is needed. Our existing protocol is preceded by 2 d of adaptation to a low 13C formula diet at a protein intake of 1 g. kg-1. d-1 to minimize variations in breath 13CO2 enrichment and protein metabolism. To expand on our potential study populations, a less invasive protocol needs to be developed. We have already established that a stable background 13CO2 enrichment can be achieved on the study day without prior adaptation to the low 13C formula. Therefore, this study investigates phenylalanine kinetics in response to variations in prior protein intake. Healthy adult subjects were each fed nutritionally adequate mixed diets containing 0.8, 1.4 and 2.0 g protein. kg-1. d-1 for 2 d. On d 3, subjects consumed an amino acid-based formula diet containing the equivalent of 1 g protein. kg-1. d-1 hourly for 10 h and primed hourly oral doses of L-[1-13C]phenylalanine for the final 6 h. Phenylalanine kinetics were calculated from plasma-free phenylalanine enrichment and breath 13CO2 excretion. A significant quadratic response of prior protein intake on phenylalanine flux (P = 0.012) and oxidation (P = 0.009) was identified, such that both variables were lower following adaptation to a protein intake of 1.4 g. kg-1. d-1. We conclude that variations in protein intake, between 0.8 and 2.0 g. kg-1. d-1, prior to the study day may affect amino acid kinetics and; therefore, it is prudent to continue to control protein intake prior to an amino acid kinetics study.  (+info)

(3/4907) Lysine deficiency alters diet selection without depressing food intake in rats.

Under states of protein deficiency, the dietary limiting amino acid, rather than protein content, can act as the dietary stimulus to control diet selection. If fact, threonine-deficient rats will alter their diet selection patterns solely on the basis of very small changes (0.009 g/100 g) in the dietary threonine concentration. In these studies, we assessed whether lysine-deficient rats will also alter their diet selection patterns on the basis of small changes in dietary Lys concentration. In all experiments, growing rats were adapted to diets in which the protein fraction (purified amino acids or wheat gluten) was limiting in Lys. They were then given a choice between the adaptation diet (AD) diet and a slightly more deficient diet. Rats that were adapted to a Lys-deficient diet (0.25 g Lys/100 g) selected their AD over diets containing as little as 0.01% less Lys (P < 0.01) within 5 d. To determine how deficient rats must be before they alter their selection patterns, rats were adapted to diets containing various levels of Lys, i.e., 2 levels below the requirement for growth and 2 levels above the requirement for growth, but below the requirement for maximal nitrogen retention. Only rats adapted to diets containing Lys below their requirement for growth selected their AD over a diet containing 0.05% less Lys (P < 0.005). Finally, to determine whether rats will alter their selection to whole protein-based diets, rats were adapted to 25% wheat gluten diets supplemented with 0.03-0.21% Lys. Rats selected the AD over a diet containing as little as 0.09% less supplemental Lys by d 4 of the trial (P < 0.05). We conclude that rats are sensitive to changes as small as 0.01% in dietary Lys concentration, but that sensitivity requires prior adaptation to Lys-deficient diets.  (+info)

(4/4907) Ruminally undegraded intake protein in sheep fed low-quality forage: effect on weight, growth, cell proliferation, and morphology of visceral organs.

To determine the influence of increasing levels of supplemental ruminally undegraded intake protein (UIP) on visceral organ weights, growth, cell proliferation, and morphology, 20 mature ewes of mixed breeding were fed a 6.55% CP grass hay:straw mixture (40:60) and assigned to one of four supplemental treatments. Supplements were control (no supplement) and low, medium, and high levels of UIP. After 42 to 46 d on treatment, ewes were infused i.v. with 5-bromo-2-deoxy-uridine (BrdU, a thymidine analog used to provide an index of the rate of intestinal cell proliferation) and slaughtered 1 h later. Visceral organs were weighed, and subsamples were obtained to evaluate visceral DNA, RNA, and protein contents (frozen samples) as well as intestinal morphology (fixed samples). Final BW; eviscerated BW (EBW); total visceral weight; and liver fresh, dry, and dry fat-free weights were increased (P<.10) in protein-supplemented ewes compared with controls, but were not influenced by increasing levels of UIP. Tissue weights of duodenum, jejunum, ileum, cecum, and colon were not greatly influenced by treatment. There were no differences among treatments in intestinal DNA and protein concentrations and the ratios RNA:DNA and protein:DNA. Jejunal RNA concentration and content was increased (P<.10) in low compared with medium and high treatments. Jejunal RNA content also was decreased (P<.10) in high compared with the medium UIP treatment. Liver RNA and protein contents were increased (P<.10) with protein supplementation. In contrast, contents of RNA, DNA, and protein in duodenum, ileum, cecum, and colon were not influenced by treatment. In addition, neither the rate of intestinal proliferation (BrdU labeling) nor intestinal morphology (crypt depth, villus length, or villus width) were affected by treatment. These data indicate that the influence of protein supplementation on visceral growth involves primarily the liver and not the intestines. These data also indicate that visceral growth, except in jejunum, are not altered by differing levels of UIP supplementation.  (+info)

(5/4907) Fermentation substrate and dilution rate interact to affect microbial growth and efficiency.

The effect of dilution rate (D) on carbohydrate, fibrous and nonfibrous, and protein fermentation by ruminal microorganisms was studied using a single-effluent continuous-culture system. The diets of fibrous carbohydrate, nonfibrous carbohydrate, or protein were formulated with soybean hulls (FC), ground corn (NFC), or isolated soy protein (PR) as the primary ingredient, respectively. Six dilution rates (.025, .050, .075, .10, .15, and .20/h of fermenter volume) were used. Digestibilities of DM, OM, and CP for the three diets and of NDF and ADF for the FC diet decreased (P<.001) as D increased, although the response of the digestibility to D varied with diet. Increasing D resulted in an increase in pH (P<.001) and a decrease (P<.001) in ammonia concentration. Daily volatile fatty acid production increased (quadratic; P<.01) for the FC and NFC diets, but decreased (quadratic; P<.001) for the PR diet. Increasing D quadratically increased (P<.001) the molar percentage of acetate and propionate, but quadratically decreased (P<.001) butyrate and valerate for the FC and NFC diets. For the PR diet, the molar percentage of propionate and valerate increased (quadratic; P<.01), whereas acetate and butyrate decreased (linear; P<.001) in response to increasing D. Molar percentage of isobutyrate and isovalerate decreased (P<.01) with increasing D for all three diets. As D increased, daily microbial N production showed quadratic responses with maximum values achieved at .126, .143, and .187/h D for the FC, NFC, and PR diet, respectively. There was a positive correlation between microbial growth efficiency (MOEFF) and D. A quadratic model fit the data of MOEFF as affected by D, and maximum MOEFF of 37.3, 59.6, and 71.4 g of bacterial N/kg OM truly fermented were calculated to be achieved at .177, .314, and .207/h D for the FC, NFC, and PR diet, respectively. Dilution rate significantly influenced the ruminal microbial fermentation of fibrous and nonfibrous carbohydrates and proteins, and was positively related to microbial yield and growth efficiency. In addition, microbial nitrogen composition, and therefore efficiency, was affected by substrate fermented.  (+info)

(6/4907) Nitrogen retention by lambs fed oscillating dietary protein concentrations.

Nitrogen excreted by beef cattle can be retained in manure or lost by volatilization to the atmosphere or by runoff and percolation into surface or ground water. Increasing the retention of dietary N should decrease environmental losses. To this end, the effects of oscillating concentrations of dietary CP on nutrient retention were determined using lambs fed a 90% concentrate diet. Ten St. Croix lambs (average BW = 27 kg) were used in two 5x5 Latin square experiments. Dietary treatments were as follows: 1) 10% CP, 2) 12.5% CP, 3) 15% CP, 4) 10% and 15% CP diets oscillated at 24-h intervals, and 5) 10% and 15% CP diets oscillated at 48-h intervals. Supplemental N was provided by cottonseed meal in Trial 1 and by a 50:50 (N basis) blend of cottonseed meal and urea in Trial 2. Each period of the Latin square lasted 35 d, with excreta collection the final 8 d. Nitrogen retention increased linearly (P<.01) with increasing N intake in both trials (.77, 1.33, and 1.89 g/d for 10, 12.5, and 15% CP, respectively, in Trial 1; .94, 1.78, and 2.19 g/d for 10, 12.5, and 15% CP, respectively, in Trial 2). Compared with continuously feeding the 12.5% CP diet, oscillating the 10 and 15% CP diets on a 24-h basis did not affect N retention (P>.10) in either trial (1.62 and 1.56 g/d for Trials 1 and 2, respectively). Oscillating dietary CP at 48-h intervals did not affect N retention in Trial 2 (1.82 g/d) but increased (P<.05) N retention by 38% in Trial 1 (1.87 g/d). Phosphorus, K, and Na retention and excretion were not affected by dietary treatments in Trial 1. In Trial 2, P retention increased (linear, P<.05) with increasing dietary CP and was greater (P<.05) in lambs on the 48-h oscillation treatment than in lambs fed the 12.5% CP diet. These results suggest that oscillating the dietary CP concentrations might potentially increase the utilization of N by ruminants fed high-concentrate diets.  (+info)

(7/4907) Hormone-related, muscle-specific changes in protein metabolism and fiber type profile after faba bean intake.

Male growing Wistar rats were fed, over 15 days, isoenergetic (16.72 +/- 0.49 MJ) and isoproteic (11%) diets containing either lactalbumin or raw Vicia faba L. (Vf) as the sole source of protein. Compared with pair-fed controls (PF), soleus muscles of Vf-fed rats showed increased (P < 0.05) synthesis and breakdown rates. In addition, the soleus of Vf-fed rats displayed a decrease (P < 0.05) in type I and an increase (P < 0.01) in type IIc fibers compared with that of PF animals. On the contrary, extensor digitorum longus muscles of both Vf-fed and PF rats showed an increase (P < 0.01) in type I and a reduction (P < 0.05) in type IIb fibers together with a decrease (P < 0.05) in the cross-sectional area of the latter fibers. Vf-fed rats exhibited a significant decrease in serum insulin (P < 0.05) and thyrotropin (P < 0.01) levels, together with an increase in plasma glucagon (P < 0.05) and 3,5,3'-triiodothyronine (P < 0.01) concentrations, compared with the PF group. Both Vf-fed and PF rats experienced an increase in corticosterone concentrations (P < 0.01 vs. control; P < 0.05 vs. PF). The muscle-specific changes in both protein metabolism and fiber type composition may partly depend on the hormonal changes that were observed after Vf intake.  (+info)

(8/4907) Lipoprotein(a) and dietary proteins: casein lowers lipoprotein(a) concentrations as compared with soy protein.

BACKGROUND: Substitution of soy protein for casein in the diet decreases LDL cholesterol and increases HDL cholesterol. How the 2 proteins affect lipoprotein(a) [Lp(a)], an independent risk factor for coronary artery disease, is unknown. OBJECTIVE: We compared the effects of dietary soy protein and casein on plasma Lp(a) concentrations. DESIGN: Nine normolipidemic men were studied initially while consuming their habitual, self-selected diets, and then, in a crossover design, while consuming 2 liquid-formula diets containing either casein or soy protein. The dietary periods lasted 45 d (n = 7) or 33 d (n = 2). Fasting total cholesterol, LDL-cholesterol, HDL-cholesterol, triacylglycerol, and Lp(a) concentrations were measured throughout. RESULTS: After 30 d of each diet, the mean concentration of Lp(a) was not significantly different after the soy-protein and self-selected diets. However, Lp(a) decreased by an average of 50% (P < 0.001) after the casein diet as compared with concentrations after both the soy-protein and self-selected diets. Two weeks after subjects switched from the self-selected to the soy-protein diet, Lp(a) increased by 20% (P = 0.065), but subsequently decreased to baseline. In contrast, the switch to the casein diet did not cause an increase in Lp(a), but instead a continuing decrease in mean concentrations to 65% below baseline (P < 0.0002). Total cholesterol, LDL cholesterol, and HDL cholesterol were significantly lower > or =30 d after both the casein and soy-protein diets than after the self-selected diet (P < 0.001). HDL cholesterol was 11% higher after the soy-protein diet than after the casein diet (P < 0.002), but LDL cholesterol, total cholesterol, and triacylglycerol were not significantly different after the casein and soy-protein diets. CONCLUSION: These findings indicate that soy protein may have an Lp(a)-raising effect, potentially detrimental to its use in antiatherogenic diets.  (+info)