Whole-grain diets reduce blood pressure in mildly hypercholesterolemic men and women.

The objective of this study was to compare the effects on blood pressure of predominantly insoluble fiber (whole wheat and brown rice) and soluble fiber (barley) in a whole-grain diet. Subjects (seven men, nine premenopausal women, and nine postmenopausal women) consumed a controlled Step I diet for 2 weeks; then about 20% of energy was replaced with whole wheat/brown rice, barley, or half wheat-rice/half barley, for 5 weeks each. Blood pressure was determined weekly and weight daily before breakfast. Urinary excretions of minerals that might affect blood pressure and urea nitrogen were determined each period. Systolic pressure was lower after the wheat/rice and half-and-half diets. Diastolic and mean arterial pressures were reduced by all whole-grain diets. No differences were observed in urinary measurements. In a healthful diet, increasing whole-grain foods, whether high in soluble or insoluble fiber, can reduce blood pressure and may help to control weight.

Consumption of both resistant starch and beta-glucan improves postprandial plasma glucose and insulin in women.

OBJECTIVE: Consumption of a meal high in resistant starch or soluble fiber (beta-glucan) decreases peak insulin and glucose concentrations and areas under the curve (AUCs). The objective was to determine whether the effects of soluble fiber and resistant starch on glycemic variables are additive. RESEARCH DESIGN AND METHODS: Ten normal-weight (43.5 years of age, BMI 22.0 kg/m2) and 10 overweight women (43.3 years of age, BMI 30.4 kg/m2) consumed 10 tolerance meals in a Latin square design. Meals (1 g carbohydrate/kg body wt) were glucose alone or muffins made with different levels of soluble fiber (0.26, 0.68, or 2.3 g beta-glucan/100 g muffin) and three levels of resistant starch (0.71, 2.57, or 5.06 g/100 g muffin). RESULTS: Overweight subjects had plasma insulin concentrations higher than those of normal-weight subjects but maintained similar plasma glucose levels. Compared with low beta-glucan-low resistant starch muffins, glucose and insulin AUC decreased when beta-glucan (17 and 33%, respectively) or resistant starch (24 and 38%, respectively) content was increased. The greatest AUC reduction occurred after meals containing both high beta-glucan-high resistant starch (33 and 59% lower AUC for glucose and insulin, respectively). Overweight women were somewhat more insulin resistant than control women. CONCLUSIONS: Soluble fiber appears to have a greater effect on postprandial insulin response while glucose reduction is greater after resistant starch from high-amylose cornstarch. The reduction in glycemic response was enhanced by combining resistant starch and soluble fiber. Consumption of foods containing moderate amounts of these fibers may improve glucose metabolism in both normal and overweight women.

Prediagnostic plasma vitamin C levels and the subsequent risk of prostate cancer.

OBJECTIVE: Antioxidants, such as vitamin C, are hypothesized to prevent prostate carcinogenesis by protecting the DNA from oxidative damage. We assessed whether higher prediagnostic plasma concentrations of vitamin C were associated with a lower risk of prostate cancer in a well-nourished cohort of men. METHODS: Plasma concentrations of ascorbic acid (vitamin C) were previously determined in blood specimens collected between 1984 and 1990 in men participating in the Baltimore Longitudinal Study of Aging. Total plasma ascorbic acid (L-ascorbic acid plus dehydro-L-ascorbic acid) levels were measured by using a modification of the 2,4-dinitrophenylhydrazine method. Among the 498 male participants with measured plasma vitamin C levels, 62 men were subsequently diagnosed with prostate cancer during their lifetime. Cox proportional hazards regression models were used to estimate relative risks and 95% confidence intervals for prostate cancer. RESULTS: The median plasma concentration of vitamin C for the cohort was 1.17 mg/dL, which is in the normal to high range for older men. The age-adjusted relative risk of prostate cancer for the highest quartile (median = 1.47 mg/dL, range = 1.36-2.58) compared with the lowest quartile (median = 0.83 mg/dL, range = 0.15-0.98) of plasma vitamin C concentration was 1.31 (95% confidence interval 0.63 to 2.70, P for trend = 0.29). Adjustment for cigarette smoking status, body mass index, or plasma cholesterol concentration did not attenuate the results. CONCLUSIONS: This small but prospective study suggests that higher plasma vitamin C concentrations within the normal physiologic range are not associated with a lower risk of prostate cancer in well-nourished men.

Comparison of hormone and glucose responses of overweight women to barley and oats.

OBJECTIVE: To determine the effect of particle size (flour vs. flakes) on glycemic responses after oats and barley (Prowashonupana cultivar), which contain high amounts of soluble fiber, are consumed by overweight women. DESIGN: Ten women, average age 50 years and body mass index 30, consumed glucose (1 g/kg body weight) and four test meals (1 g carbohydrate/kg body weight; 2/3 of the carbohydrate from oat flour, oatmeal, barley flour, or barley flakes and 1/3 from pudding) in a Latin square design after consuming controlled diets for 2 days. Blood samples were collected at fasting and periodically after each meal. RESULTS: Peak glucose and insulin levels after barley were significantly lower than those after glucose or oats. Glucose areas under the curve (AUCs) after test meals compared with AUCs after glucose were reduced after both oats and barley (29-36% by oats and 59-65% by barley) (p < 0.002). Insulin AUCs after test meals compared with glucose AUCs were significantly reduced only by barley (44-56%) (p < 0.005). Indexes for insulin resistance (HOMA, MFFM, Cederholm) after the oat and barley meals were not different from indexes after the glucose meal. Glucagon and leptin responses did not significantly differ for the carbohydrates tested. CONCLUSIONS: Particle size of the oats or barley had little effect on the glycemic responses. Both oat and barley meals reduced glycemic responses; the high soluble fiber content of this barley appeared to be a factor in the greater reduction observed.

The combination of high fruit and vegetable and low saturated fat intakes is more protective against mortality in aging men than is either alone: the Baltimore Longitudinal Study of Aging.

Saturated fat (SF) intake contributes to the risk of coronary heart disease (CHD) mortality. Recently, the protective effects of fruit and vegetable (FV) intake on both CHD and all-cause mortality were documented. However, individuals consuming more FV may be displacing higher-fat foods. Therefore, we investigated the individual and combined effects of FV and SF consumption on total and CHD mortality among 501 initially healthy men in the Baltimore Longitudinal Study of Aging (BLSA). Over a mean 18 y of follow-up, 7-d diet records were taken at 1-7 visits. Cause of death was ascertained from death certificates, hospital records, and autopsy data. After adjustment for age, total energy intake, BMI, smoking, alcohol use, dietary supplements, and physical activity score, FV and SF intakes were individually associated with lower all-cause and CHD mortality (P < 0.05). When both FV and SF were included in the same model, associations of each were attenuated with CHD mortality, and no longer significant for all-cause mortality. Men consuming the combination of > or =5 servings of FV/d and < or =12% energy from SF were 31% less likely to die of any cause (P < 0.05), and 76% less likely to die from CHD (P < 0.001), relative to those consuming < 5 FV and >12% SF. Men consuming either low SF or high FV, but not both, did not have a significantly lower risk of total mortality; but did have 64-67% lower risk of CHD mortality (P < 0.05) relative to those doing neither. These results confirm the protective effects of low SF and high FV intake against CHD mortality. In addition, they extend these findings by demonstrating that the combination of both behaviors is more protective than either alone, suggesting that their beneficial effects are mediated by different mechanisms.

Reduced risk of Alzheimer's disease with high folate intake: the Baltimore Longitudinal Study of Aging.

BACKGROUND: Study findings have suggested an association between Alzheimer's disease (AD) risk and several vitamins and have speculated about their use as preventive agents. Here, we examine whether total intake (intake from diet plus supplements) of antioxidant vitamins (E, C, carotenoids) and B vitamins (folate, B(6), and B(12)) is associated with a reduced risk of AD. METHODS: Participants were 579 nondemented elderly volunteers from the Baltimore Longitudinal Study of Aging who completed dietary diaries and recorded supplement intake for a 7-day period. Cox regression was used to estimate the relative risk (RR) of AD associated with total vitamin intake categorized into levels above or below the Recommended Dietary Allowance (RDA). RESULTS: After a mean follow-up of 9.3 years, AD developed in 57 participants. Higher intake of folate (RR, 0.41; 95% confidence interval [CI], 0.22 to 0.76), vitamin E (RR, 0.56; 95% CI, 0.30 to 1.06), and vitamin B(6) (RR, 0.41; 95% CI, 0.20 to 0.84) were associated individually with a decreased risk of AD after adjusting for age, gender, education, and caloric intake. When these 3 vitamins were analyzed together, only total intake of folate at or above the RDA (RR, 0.45; 95% CI, 0.21 to 0.97) was associated with a significant decreased risk of AD. No association was found between total intake of vitamins C, carotenoids, or vitamin B(12) and risk of AD. CONCLUSIONS: These findings suggest that total intake of folate at or above the RDA is associated with a reduced risk of AD. Additional studies are necessary to further investigate whether folate or other(s) unmeasured factor(s) may be responsible for this reduction in risk.

Diets containing barley significantly reduce lipids in mildly hypercholesterolemic men and women.

BACKGROUND: Barley has high amounts of soluble fiber but is not extensively consumed in the US diet. OBJECTIVE: This study investigated whether consumption of barley would reduce cardiovascular disease risk factors comparably with that of other sources of soluble fiber. DESIGN: Mildly hypercholesterolemic subjects (9 postmenopausal women, 9 premenopausal women, and 7 men) consumed controlled American Heart Association Step 1 diets for 17 wk. After a 2-wk adaptation period, whole-grain foods containing 0, 3, or 6 g beta-glucan/d from barley were included in the Step 1 diet menus. Diets were consumed for 5 wk each and were fed in a Latin-square design. Fasting blood samples were collected twice weekly. RESULTS: Total cholesterol was significantly lower when the diet contained 3 or 6 g beta-glucan/d from barley than when it contained no beta-glucan; the greatest change occurred in the men and postmenopausal women. HDL and triacylglycerol concentrations did not differ with the 3 amounts of dietary beta-glucan. Large LDL and small VLDL fractions and mean LDL particle size significantly decreased when whole grains were incorporated into the 3 diets. Large LDL and large and intermediate HDL fractions were significantly higher, mean LDL particle size was significantly greater, and intermediate VLDL fractions were significantly lower in the postmenopausal women than in the other 2 groups. A group-by-diet interaction effect was observed on LDL fractions and small LDL particle size. CONCLUSION: The addition of barley to a healthy diet may be effective in lowering total and LDL cholesterol in both men and women.

Food patterns measured by factor analysis and anthropometric changes in adults.

BACKGROUND: Sixty-five percent of US adults are overweight, and 31% of these adults are obese. Obesity results from weight gains over time; however, dietary determinants of weight gain remain controversial. OBJECTIVE: Our objective was to examine whether food patterns derived from exploratory factor analysis are related to anthropometric changes. We hypothesized that we would derive a healthy food pattern and that it would predict smaller changes in body mass index (BMI; in kg/m(2)) and waist circumference (in cm) than would other food patterns in models adjusted for baseline anthropometric measures. DESIGN: The subjects were 459 healthy men and women participating in the Baltimore Longitudinal Study of Aging. Diet was assessed by using 7-d dietary records, from which 40 food groups were formed and entered into a factor analysis. RESULTS: Six food patterns were derived. Factor 1 (reduced-fat dairy products, fruit, and fiber) was most strongly associated with fiber (r = 0.39) and loaded heavily on reduced-fat dairy products, cereal, and fruit and loaded moderately on fruit juice, nonwhite bread, nuts and seeds, whole grains, and beans and legumes. In a multivariate-adjusted model in which the highest and lowest quintiles were compared, factor 1 was inversely associated with annual change in BMI (beta = -0.51; 95% CI: -0.82, -0.20; P < 0.05; P for trend < 0.01) in women and inversely associated with annual change in waist circumference (beta = -1.06 cm; 95% CI: -1.88, -0.24 cm; P < 0.05; P for trend = 0.04) in both sexes. CONCLUSION: Our results suggest that a pattern rich in reduced-fat dairy products and high-fiber foods may lead to smaller gains in BMI in women and smaller gains in waist circumference in both women and men.

In situ soil treatments to reduce the phyto- and bioavailability of lead, zinc, and cadmium.

A study was established near a former Zn and Pb smelter to test the ability of soil amendments to reduce the availability of Pb, Zn, and Cd in situ. Soil collected from the field was amended in the lab with P added as 1% P-H3PO4, biosolids compost added at 10% (referred to hereafter as "compost"), and a high-Fe by-product (referred to hereafter as "Fe") + P-triple superphosphate (TSP) (2.5% Fe + 1% P-TSP) and incubated under laboratory conditions at a constant soil pH. Changes in Pb bioavailability were measured with an in vitro test and a feeding study with weanling rats. Field-amended and incubated soils using these plus additional treatments were evaluated using the in vitro extraction and tall fescue (Festuca arundinacea Schreb. cv. Kentucky-31) metal concentration. Reductions were observed across all parameters but were not consistent. In the feeding study, the 1% P-H3PO4 and compost treatments resulted in a decrease of 26% in rat tissue Pb concentration compared with the control soil. The 2.5% Fe + 1% P-TSP showed a 39% decrease. The 1% P-H3PO4 treatment caused the greatest reduction in in vitro extractable Pb from field samples (pH 2.2) with a measured reduction of 66%, while the compost treatment had a 39% reduction and the 2.5% Fe + 1% P-TSP treatment a 50% reduction. The in vitro extraction (pH 1.5) run on field samples showed no reduction in the compost or Fe treatments. The 1% P-H3PO4 treatment was the most effective at reducing plant Pb, Zn, and Cd.

Lipids significantly reduced by diets containing barley in moderately hypercholesterolemic men.

OBJECTIVE: To determine whether barley, as the soluble fiber source, would beneficially change cardiovascular risk factors. Soluble fiber from oats has been recognized as beneficial in decreasing blood cholesterol levels. Although barley contains high amounts of soluble fiber, it is not consumed as extensively as oats. METHODS: Eighteen moderately hypercholesterolemic men (28-62 y) consumed a controlled equilibration diet (Step 1, 30% fat, 55% carbohydrate, 15% protein, < 300 mg cholesterol) for 2 weeks followed by the diet with about 20% of energy replaced with brown rice/whole wheat, (1/2) barley & (1/2) brown rice/whole wheat or barley (< 0.4 g, 3 g and 6 g added soluble fiber/2800 kcal, respectively) for 5 weeks in a Latin square design. Fasting blood was drawn twice weekly. Total cholesterol, HDL cholesterol, and triacylglycerols were measured enzymatically and lipid fractions were measured by nuclear magnetic resonance spectroscopy. RESULTS: Compared with prestudy concentrations, total cholesterol (14%, 17%, and 20%, respectively) and LDL cholesterol (17%, 17%, and 24%, respectively) were significantly lower (p < 0.0001) after the low, medium, and high-soluble fiber diets. Triacylglycerol was 6%, 10%, and 16% lower (p = 0.09) whereas HDL cholesterol (9%, 7%, and 18%) was higher (p < 0.001) after the experimental diets. Total cholesterol and LDL cholesterol after the high-soluble fiber diet were significantly lower than concentrations after the low- or medium-soluble fiber diets. Mean LDL particle number significantly decreased (p < 0.007) and the large LDL cholesterol fraction showed a trend toward lower concentrations (p = 0.06). CONCLUSION: Increasing soluble fiber through consumption of barley in a healthy diet can reduce cardiovascular risk factors.

Atypically high insulin responses to some foods relate to sugars and satiety.

Much research has focused on how the glycemic index (GI) of the diets of healthy people relates to long-term risk for coronary heart disease, stroke, and non-insulin dependent diabetes. Low-GI diets appear to produce some of their beneficial effects largely by moderating insulinemic responses to meals. Wolever and Bolognesi (1996) have derived a formula for predicting the insulinemic index (II) from the GI for starchy foods. Using data from Holt et al. (1995, 1997) on a wide variety of common foods, we have examined differences between the observed II and GI-based estimates of the II. These differences were found to correlate negatively with satiety index ratings and positively with contents of total sugars. We suggest that the aforementioned method of measuring and expressing the relation between the GI and the II may prove useful in exploring how various components and sensory properties of food may affect hunger and energy intake.

Dietary patterns and changes in body mass index and waist circumference in adults.

BACKGROUND: Obesity has increased > 20% in the past decade in the United States, and more than one-half of US adults are overweight or obese. OBJECTIVE: Our objective was to further elucidate the nutritional etiology of changes in body mass index (BMI; in kg/m(2)) and waist circumference by dietary intake pattern. We hypothesized that a healthy dietary pattern would lead to smaller changes in BMI and waist circumference than would other dietary patterns. DESIGN: Subjects were 459 healthy men and women participating in the ongoing Baltimore Longitudinal Study of Aging. Diet was assessed with the use of 7-d dietary records, from which 41 food groups were created and entered into a cluster analysis. RESULTS: Five dietary patterns were derived (healthy, white bread, alcohol, sweets, and meat and potatoes). The mean annual change in BMI was 0.30 +/- 0.06 for subjects in the meat-and-potatoes cluster and 0.05 +/- 0.06 for those in the healthy cluster (P < 0.01). The mean annual change in waist circumference was more than 3 times as great for subjects in the white-bread cluster (1.32 +/- 0.29 cm) as for those in the healthy cluster (0.43 +/- 0.27 cm) (P < 0.05). CONCLUSIONS: Consuming a diet high in fruit, vegetables, reduced-fat dairy, and whole grains and low in red and processed meat, fast food, and soda was associated with smaller gains in BMI and waist circumference. Because foods are not consumed in isolation, dietary pattern research based on natural eating behavior may be useful in understanding dietary causes of obesity and in helping individuals trying to control their weight.

Effect of biosolids processing on lead bioavailability in an urban soil.

The potential for biosolids products to reduce Pb availability in soil was tested on a high Pb urban soil with biosolids from a treatment plant that used different processing technologies. High Fe biosolids compost and high Fe + lime biosolids compost from other treatment plants were also tested. Amendments were added to a Pb-contaminated soil (2000 mg kg(-1) Pb) at 100 g kg(-1) soil and incubated for 30 d. Reductions in Pb bioavailability were evaluated with both in vivo and in vitro procedures. The in vivo study entailed feeding a mixture of the Pb-contaminated soil and AIN93G Basal Mix to weanling rats. Three variations of an in vitro procedure were performed as well as conventional soil extracts [diethylenetriaminepentaacetic acid (DTPA) and Ca(NO3)2] and sequential extraction. Addition of the high Fe compost reduced the bioavailability of soil Pb (in both in vivo and in vitro studies) by 37 and 43%, respectively. Three of the four compost materials tested reduced Pb bioavailability more than 20%. The rapid in vitro (pH 2.3) data had the best correlation with the in vivo bone results (R = 0.9). In the sequential extract, changes in partitioning of Pb to Fe and Mn oxide fractions appeared to reflect the changes in in vivo Pb bioavailability. Conventional extracts showed no changes in metal availability. These results indicate that addition of 100 g kg(-1) of high Fe and Mn biosolids composts effectively reduced Pb availability in a high Pb urban soil.

Glucose and insulin responses to a new zero-energy fiber source.

OBJECTIVE: Consumption of a number of soluble fiber sources reduces glucose and insulin responses in humans. These fibers provide some available energy. Z-trim, a completely insoluble, noncaloric fiber/fat replacer produced from grain, was developed by ARS scientist George Inglett but until this report had not been tested in humans. The objective was to test the effects of consumption of various doses of this new fiber on glucose and insulin responses in humans. DESIGN: Men and women (12 each) matched for age and body mass index (41 years, BMI 27) were given glucose or glucose with three levels of fiber in a Latin-square design. Blood samples were obtained before and 30, 60, 120 and 180 minutes after solutions containing glucose alone (1 g/kg body weight) and glucose plus 0.08, 0.17 and 0.33 g/kg body weight of Z-trim were consumed. Plasma glucose, insulin and glucagon were determined by enzyme or radioimmunoassays. A repeated-measures analysis of variance was conducted. RESULTS: Glucose responses were lower for women than for men (p = 0.02) regardless of the test solution. At 30 minutes, glucose levels of men were 0.7-1.1 mmol/L lower after the two higher levels of fiber than after glucose alone. Insulin peak responses were delayed by high amounts of Z-trim. Fasting and response levels of glucagon were higher (p < 0.002) in women than in men. The decline in glucagon usually seen after a glucose load was moderated by the addition of fiber. CONCLUSION: Although high levels of this new fiber may beneficially affect glucose metabolism of middle-aged people, it is less effective than soluble fiber.