Warren Peters

Dietary intake and biochemical, hematologic, and immune status of vegans compared with nonvegetarians

Dietary and nutritional status of individuals habitually consuming a vegan diet was evaluated by biochemical, hematologic, and immunologic measures in comparison with a nonvegetarian group. On the basis of 4-d dietary records, the intake of female and male vegans tended to be lower in fat, saturated fat, monounsaturated fat, and cholesterol and higher in dietary fiber than that of vegetarians. With computed food and supplement intakes, vegan diets provided significantly higher amounts of ascorbate, folate, magnesium, copper, and manganese in both female and male participants. The body mass index (BMI; in kg/m(2)) of the vegans was significantly lower than that of the nonvegetarians and 9 of the 25 vegans had a BMI <19. Serum ferritin concentrations were significantly lower in vegan men but iron and zinc status did not differ between the sexes. Mean serum vitamin B-12 and methylmalonic acid concentrations did not differ; however, 10 of the 25 vegans showed a vitamin B-12 deficit manifested by macrocytosis, circulating vitamin B-12 concentrations <150 pmol/L, or serum methylmalonic acid >376 nmol/L. Vegans had significantly lower leukocyte, lymphocyte, and platelet counts and lower concentrations of complement factor 3 and blood urea nitrogen but higher serum albumin concentrations. Vegans did not differ from nonvegetarians in functional immunocompetence assessed as mitogen stimulation or natural killer cell cytotoxic activity.

Reproducibility of DXA in Obese Women

Dual-energy X-ray absorptiometry (DXA) measurements were analyzed using two versions of software (Hologic V8.1a and V8.21) to compare the short- and long-term precisions of the measurements. Software V8.21 was designed by the manufacturer to better address magnification effects on estimations of soft tissue lean mass. Twenty weight-stable, obese postmenopausal Caucasian women aged 40-70 yr participated in the study. Total and regional body composition measurements were obtained at baseline and after 3 mo, using a fan beam Hologic QDR 4500A absorptiometer. For the estimation of precision, duplicate scans obtained on the same day for nine women were analyzed using both versions of the software. The correlations between duplicate scans ranged from 0.886 to 0.998 and were similar between software versions. The CVs for fat and lean weights and bone mineral content (BMC) were 1.2%, 1.1%, and 1.7%, respectively, for software V8.21 compared to 1.3%, 1.3%, and 2.1%, respectively, for V8.1a. Systematic differences were found between software versions with higher values for fat and lean weights for software version V8.21. The 3-mo, long-term reproducibility of body composition estimates from DXA was only slightly less than short-term reproducibility for both software versions (coefficient of variation [CV] range from 1.3% for BMC weight to 11.0% for arm fat). Software V8.21 yielded smaller percentage mean differences between scale and DXA-estimated weights (-2.4% and -7.2% at baseline and -2.9% and -7.6% at 3 mo, respectively) and higher fat and lean weights (49.12 and 47.1 kg and 49.6 and 44.6 kg, respectively) than V8.1a. Reproducibility of all variables was comparable between software versions.

Association of the acid phosphatase (ACP1) gene with triglyceride levels in obese women

The acid phosphatase (ACP1) locus codes for a low molecular weight protein tyrosine phosphatase (LMPTP) that is found ubiquitously in human tissues. The *A allele of the ACP1 gene is associated with lower total enzymatic activity than the *B and *C alleles. An association between the *A allele and extreme values of body-mass-index (BMI) and dyslipidemia has previously been described in several samples of obese subjects from the Italian population. In the present study, we investigated the relationship between ACP1 *A allele genotypes (*A/*A, *A/*B, and *A/*C) and non-*A allele genotypes (*B/*B, *B/*C, and *C/*C) and metabolic variables in 277 Caucasian post-menopausal subjects consisting of 82 non-obese subjects (BMI</=29), 60 moderately obese (BMI 30-34) and 135 very obese (BMI>/=35) subjects. ACP1 genotypes were found to be significantly associated with total cholesterol (p</=0.002) and triglyceride (p</=0.001) levels in the obese and very obese women only. The significantly lower levels of triglycerides in *A carriers in this group suggest a protective effect of the *A allele against hypertriglyceridemia. It has been unclear why some individuals who gain weight develop dyslipidemia and other aspects of the metabolic syndrome while others do not. The present study suggests that those who gain weight and carry the ACP1 *A allele may be partially protected against developing the metabolic syndrome. The confirmation of ACP1 as a modifier gene of the metabolic complications could open the door to the prevention of the lethal complications of obesity.

Weight loss is correlated with an improved lipoprotein profile in obese postmenopausal women

Background: Changes in plasma lipid and lipoprotein distributions that occur after menopause increase the risk of cardiovascular disease in women, especially in those who are overweight. Objective: The purpose of this study was to evaluate the impact of a nine-month weight reduction program on plasma lipids, dietary intake and abdominal fat obesity. Design: A partial crossover design was used to study a weight loss treatment consisting of Phentermine hydrochloride (Fastin®, SmithKline Beecham Pharmaceuticals, Philadelphia, PA) therapy plus a low energy diet (5040 kJ/d). Forty-seven obese, postmenopausal Caucasian women (BMI of 30–38 kg/m2) were randomized into two groups, both of which received drug and diet treatment over six months. However, Group I started the intervention program three months later than Group II. Plasma total, HDL and LDL cholesterol and triacylglycerol were measured, body composition was assessed by anthropometry and dual energy x-ray absorptiometry, and food frequency records were collected at four timepoints. Results: Over nine months, women in Group II reduced body weight (14.4%), lowered plasma concentrations of LDL cholesterol (14% to 26%) and triacylglycerol (15%) and raised plasma HDL cholesterol concentration (15%). These plasma lipid changes decreased the total cholesterol/HDL cholesterol ratio from 4.3 to 3.2. All subjects decreased abdominal fat measurements and energy and cholesterol intakes, as well as percentage of energy derived from total and saturated fat during the study. Most subjects also increased dietary fiber consumption. Conclusion: Both weight loss and diet modifications are associated with an improved plasma lipid profile in obese postmenopausal women.

Effect of a Weight-Reduction Program on Total and Regional Body Composition in Obese Postmenopausal Women

The association of body fat and its distribution with risk for chronic disease is well documented.1–4 Some complications of obesity improve with a reduction in weight.5 In premenopausal women whose weight was lowered, an analysis of fat distribution by computerized tomography (CT) scan demonstrated that a decrease in the visceral/subcutaneous (V/S) ratio and in visceral fat volume was more strongly correlated with an improvement in plasma glucose and lipid metabolism than was a decrease in body weight, BMI, total fat volume, and abdominal subcutaneous fat volume. Accurate measurement of body fat and fat distribution is essential to assess the relation of regional fat mass to risk of chronic disease.6,7 The purpose of this study was to assess the impact of a weight-reduction program on total body weight loss in postmenopausal women, using indices of total and regional body composition as measured by DXA fan beam technology.

Effects of a meal replacement system alone or in combination with phentermine on weight loss and food cravings.

To examine the effects of phentermine combined with a meal replacement program on weight loss and food cravings and to investigate the relationship between food cravings and weight loss.

Reproducibility of body measurements in very obese postmenopausal women.

We compared the results of body measurements in obese women by fan-beam dualenergy X-ray absorptiometry (DXA) using two different software versions (V8.1a and V8.21) to assess their precision. Forty-five very obese postmenopausal Caucasian women aged 40–70 years old were studied (mean weight = 97.09 kg). Total and regional body composition were measured with DXA (Hologic 4500A). To assess the method’s precision, 10 women were measured, each in two trials, and the results were calculated with both software versions. TABLE 1 summarizes the mean differences between trials using software version V8.1a. As assessed by the paired t test the differences were not significant for any variables, except for lean weight (p < 0.01). In general, the mean differences between trials for all variables were less than 4%. The correlation between trials ranged from 0.886 for trunk BMC to 0.999 for total weight by DXA. The coefficient of variation (CV) for fat weight was 1.35%, for lean weight 1.38%, BMC weight 2.03%, and for total weight 0.16%. The CV for regional fat varied from 3.34% to 10.09%, regional lean from 1.38% to 4.73%, and regional BMC from 1.63% to 8.08%. TABLE 2 summarizes the mean differences between trials using software version V8.21. As assessed by the paired t test, the differences were not significant for any variables, except for fat weight (p < 0.05), fat-free mass (p < 0.01), and fat-free leg (p < 0.05). In general, the mean differences between trials were less than 4%. The high correlation between trials ranged from 0.941 for arm fat to 0.999 for fat weight. The CV for fat weight was 1.19%, for fat-free weight 1.16%, and for total weight 0.38%. The CV for regional fat varied from 3.71% (leg fat) to 10.44% (arm fat), and for regional fat-free mass from 1.96 (fat-free leg) to 5.06% (fat-free arm). TABLE 3 lists the mean differences between two software versions at baseline. The mean differences between software versions were significant (p < 0.01) for all variables except arm fat and arm lean. The percent mean difference was the largest for trunk fat and trunk lean (7.4% and 8.5% higher, respectively, for software version V8.21). For total weight, total fat weight, and total lean weight the software version V8.21 gave higher values (4.75%, 4.2%, and 5.3%, respectively). The correlation is high between both software versions for all variables. The CVs range from 0.92 (arm lean) to 2.94% (trunk fat).