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Biomedical subjects

Frank Greenway

Publications and source records attributed to Frank Greenway.

12 recordsLinked to original sources
PubMed2006

The effects of grapefruit on weight and insulin resistance: relationship to the metabolic syndrome.

To study the effects of grapefruit and grapefruit products on body weight and metabolic syndrome, 91 obese patients were randomized to either placebo capsules and 7 ounces (207 mL) of apple juice, grapefruit capsules with 7 ounces (207 mL) of apple juice, 8 ounces (237 mL) of grapefruit juice with placebo capsule, or half of a fresh grapefruit with a placebo capsule three times a day before each meal. Metabolic syndrome parameters were measured at the beginning and end of 12 weeks. After 12 weeks, the fresh grapefruit group had lost 1.6 kg, the grapefruit juice group had lost 1.5 kg, the grapefruit capsule group had lost 1.1 kg, and the placebo group had lost 0.3 kg. The fresh grapefruit group lost significantly more weight than the placebo group (P < .05). A secondary analysis of those with the metabolic syndrome in the four treatment groups demonstrated a significantly greater weight loss in the grapefruit, grapefruit capsule, and grapefruit juice groups compared with placebo (P < .02). There was also a significant reduction in 2-hour post-glucose insulin level in the grapefruit group compared with placebo. Half of a fresh grapefruit eaten before meals was associated with significant weight loss. In metabolic syndrome patients the effect was also seen with grapefruit products. Insulin resistance was improved with fresh grapefruit. Although the mechanism of this weight loss is unknown it would appear reasonable to include grapefruit in a weight reduction diet.

Beverages↗
PubMed2006

Dietary herbal supplements with phenylephrine for weight loss.

This study was designed to evaluate the efficacy and safety of a dietary herbal supplement containing citrus aurantium and phenylephrine in the treatment of obesity. Two pilot studies enrolled healthy subjects with body mass indexes 25-40 kg/m(2) to similar 8-week weight loss programs. Safety was assessed by physical examination and laboratory tests at screening and 8 weeks. The first pilot study randomized eight subjects to citrus aurantium (herbal phenylephrine) or placebo. Body composition by DEXA scan, waist circumference, and resting metabolic rate (RMR) were measured at baseline and 8 weeks. Food intake and appetite ratings were measured at baseline and week 2. The second pilot study randomized 20 subjects to two 2-hour RMR tests a week apart after phenylephrine (20 mg) or placebo followed by phenylephrine (20 mg) three times a day for 8 weeks. In the first pilot study, the citrus aurantium group gained 1.13 +/- 0.27 (mean +/- SEM) kg compared with 0.09 +/- 0.28 kg in the placebo group (P < .04). RMR at baseline rose more in the citrus aurantium group, 144.5 +/- 15.7 kcal/24 hours, than the placebo group, 23.8 +/- 28.3 kcal/24 hours (P < .002), but not at 8 weeks. DEXA, waist circumference, food intake, and hunger ratings were not different. In the second pilot study, the phenylephrine group lost 0.8 +/- 3.4 kg in 8 weeks (not significant), and RMR increased more in the phenylephrine group (111.5 +/- 32.6 vs. 37.4 +/- 22.7 kcal/24 hours, P = .02). There were no significant safety issues in either study. Although no toxicity was seen, these pilot studies suggest phenylephrine is not efficacious for weight loss.

Absorptiometry, Photon↗
PubMed2006

Globin digest: no evidence for a weight loss mechanism.

This study was designed to document the mechanism through which globin digest, a dietary herbal supplement, might cause weight loss by exploring possible fat malabsorption, calorie malabsorption, energy expenditure, and fat oxidation. Six healthy subjects were placed on an outpatient diet for 14 days and given a meal containing 40.9 g of fat on days 5 and 11, and stools were collected for 72 hours after each meal for analysis of fecal fat content. Four grams of globin digest was given with one meal and placebo with the other. In another separate study, six subjects were placed on a 100-g fat, weight-maintaining diet for 14 days. All food was prepared by the Pennington Center (Baton Rouge, LA) metabolic kitchen. Globin digest (2 g) or placebo was given with each of three meals per day, and stool was collected for calorie determinations during the last 72 hours of each week. Subjects received globin digest during one of the 2 weeks and placebo during the other. Resting metabolic rate and respiratory quotient were measured on the last day of each 1-week period. There was no increase in 72-hour fecal fat or fecal calories by bomb calorimetry during either of the studies. There was no difference in the respiratory quotient. Globin digest did result in an increase in resting metabolic rate. However, this increase was not statistically significant. Globin digest, if effective, does not cause weight loss or fat loss through fat malabsorption or a relative increase in fat oxidation. Future studies are needed to document the efficacy of globin digest for weight loss in humans before further mechanistic investigation is attempted.

Adolescent↗
PubMed2006

Virus-induced obesity.

Explore the source record for details and available documents.

Adenovirus Infections, Human↗
PubMed2005

Effects of consuming mycoprotein, tofu or chicken upon subsequent eating behaviour, hunger and safety.

This study tested if: (1) a preload of mycoprotein and tofu consumed before a lunch meal have a greater effect on satiety when compared to a chicken preload, (2) the mycoprotein and tofu preloads, compared to chicken, are not associated with compensation or eating more food at a subsequent dinner meal. These hypotheses were tested in a controlled laboratory study using universal eating monitors to measure food intake and visual analogue scales to monitor hunger and satiety. Forty-two overweight adult females consumed three meals in the laboratory on 3 test days. At lunch, isocaloric pasta preloads, containing mycoprotein, tofu, or chicken, varied across the days in a balanced order. The findings of the study supported the two hypotheses. Mycoprotein and tofu preloads, in comparison to the chicken preload, were associated with lower food intake shortly after consuming the preload at lunch. Food intake following consumption of mycoprotein and tofu did not differ, and participants did not compensate for lower food intake at lunch by consuming more food at dinner. The findings suggest that mycoprotein and tofu have satiating properties that persist for several hours after a meal. These findings have significant implications for the development of foods that are low in kilojoules, but are also filling.

Adolescent↗
PubMed2005

The effect of an herbal supplement containing black tea and caffeine on metabolic parameters in humans.

OBJECTIVE: The objective of this study was to test an herbal supplement containing black tea (the fully oxidized form of Camellia sinensis) and caffeine for stimulation of thermogenesis. METHODS/MATERIALS: A double-blind, placebo-controlled, crossover study was conducted on 16 healthy, weight-stable, non-smoking subjects, ages 21-55 years, with body mass index (BMI) of 20-30 kg/m2, and on no medications other than oral contraceptives or hormone replacement therapy. Subjects had no caffeine for 48 hours, no exercise for 24 hours, and no food for 12 hours before each visit. Area under the curve (AUC) for resting metabolic rate (RMR), respiratory quotient (RQ), blood pressure, pulse rate, and temperature were measured. At each visit RMR was measured at baseline and at one and two hours following oral administration of a supplement containing principally 600 mg black tea extract (60 percent polyphenols, 20 percent caffeine) and 442 mg guarana extract (36 percent caffeine) or matching placebo. RESULTS: The RMR and systolic blood pressure (SBP) AUCs increased significantly (p less than 0.02 and p less than 0.01, respectively) in the herbal supplement group compared to placebo. The AUC increase in RMR over the two-hour test period was 77.19 kcal/24 hr2 +/- 120.10 kcal/24 hr2 with an average rise of 52.38 +/- 29.52 kcal/24 hrs. The AUC rise in SBP over two hours was 10.3 mm Hg/hr +/- 14 mm Hg/hr. The average rise in SBP over two hours was 3.7 mm Hg +/- 4.4 mm Hg. DISCUSSION: The herbal supplement increased metabolic rate without changing substrate oxidation. The rise in SBP was consistent with the amount of caffeine the supplement contained.

Adult↗
PubMed2004

Class III obesity continues to rise in African-American women.

BACKGROUND: The Behavior Risk Factor Surveillance System (BRFSS) survey, a random telephone survey of the United States, found a rising prevalence of Class III obesity, body mass index (BMI) >40 kg/m(2). African-American women were largely responsible for this increase. The prevalence of Class III obesity in African-American women in the BRFSS during the year 2000 was 6%, identical to the Pennington Biomedical Research Center (PBRC) database during the same year. The PBRC Database might predict the trend in class III obesity in the years 2000-2002. METHODS: The PBRC is an academic research center in Baton Rouge, that maintains a database with information collected by telephone regarding BMI and race, for subjects responding to solicitations to participate in clinical trials. This database contains 7787 subjects entered from 1995 through 2002, of which 1820 were African-American women and 3006 were Caucasian women. The prevalence of Class III obesity was plotted for women of these 2 racial groups and compared with the year 2000 prevalence in the BRFSS. RESULTS: The prevalence of Class III obesity in African-American women increased from 0.5% in 1995 to 6% in 2000 (identical to the BRFSS) and to 7.5% in 2002. The prevalence of Class III obesity in Caucasian women remained about 3%. CONCLUSION: The prevalence of Class III obesity continues to rise in African-American women, a group with greater need and less access to obesity surgery, the only effective treatment, than Caucasian women, an inequality deserving of public policy attention.

Black or African American↗
PubMed2003

Clinical evaluation of the obese patient.

Evaluation of the obese patient, like the evaluation of any medical patient, involves a medical history, physical examination, and laboratory evaluation. As with any chronic illness, there are certain aspects of the history, physical, and laboratory evaluation that deserve special emphasis. This article describes those aspects that deserve special emphasis in the case of obesity.

Blood Pressure↗
PubMed2003

Time course of improved flow-mediated dilation after short-term exercise training.

PURPOSE: The purpose was to determine the influence of a unilateral localized short-term handgrip training protocol on brachial artery flow-mediated dilation (BAFMD) and to examine the time course of such changes. METHODS: Fourteen healthy males (age: 26 +/- 5.7 yr) underwent high-resolution ultrasonographic brachial artery assessments before (V1), during (V2-V7), and at the end of 4 wk (V8) of 60% maximal voluntary contraction handgrip training (20 min.d-1, 5 d.wk-1) of the nondominant arm. RESULTS: Before training resting diameters were similar between the trained (nondominant) and untrained (dominant) arms. A 2 (trained and untrained arms) x 2 (V1 and V8) repeated measure ANOVA revealed a significant main (P = 0.02 and P = 0.03) and interaction effect (P = 0.05 and P = 0.01) for the percent and absolute change in BAFMD. BAFMD improved 62% and 70%, respectively from V1 to V8, for the percent and absolute change. Subsequent linear orthogonal polynomial contrasts indicate both the percent and absolute change in BAFMD were statistically different at V2 (end of week 1 and 4 training days) from V1. These unilateral changes were not accompanied by changes in resting artery diameter, hemodynamic measures, hematological markers, and indices of heart rate variability suggesting the change may be locally mediated. CONCLUSIONS: This study shows a localized short-term exercise-training program resulted in significant improvements in BAFMD in the trained arm compared with the untrained arm and suggests this occurred after only 4 d of training.

Adaptation, Physiological↗
PubMed2002

Scrotal cooling increases rectal temperature in man.

The aim of this study was to evaluate the effect of scrotal cooling on rectal temperature in man. Pilot studies suggested that immersing the scrotum in a 30 degrees C water bath increased rectal temperature, but immersing the scrotum in a 0 degree C water bath did not. Six healthy young men immersed their scrotums in a 35 degrees C water bath for 11 min followed by 21 min at 30 degrees C. Rectal temperature rose by 0.38 +/- 0.04 degrees C (P < 0.01) in response to the 30 degrees C water bath. Repetition of the study by immersing the hands instead of the scrotum in the water bath had no effect on rectal temperature. The scrotum appears to play a role in human temperature regulation.

Body Temperature↗