Estimation of Total Body Fat from Potassium-40 Content

Forbes, Gilbert B.; Gallup, James; Hursh, John B.

doi:10.1126/science.133.3446.101

Cited by 296 publications

(43 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…17 ± 20 (2) Measurement of total body potassium (TBK) by counting the naturally occurring 40 K in a whole body counter. 20,21 TBK has a constant ratio to the FFM.…”

Section: Methodsmentioning

confidence: 99%

Influence of orlistat on bone turnover and body composition

2001

View full text Add to dashboard Cite

OBJECTIVE:To investigate the in¯uence of the pancreas lipase inhibitor orlistat (OLS) on calcium metabolism, bone turnover, bone mass, bone density and body composition when given for obesity as adjuvant to an energy-and fat-restricted diet. DESIGN: Randomized controlled double-blinded trial of treatment with OLS 120 mg three times daily or placebo for 1 y. SUBJECTS: Thirty obese subjects with a mean body mass index (BMI) of 36.9 AE 3.7 kgam 2 and a mean age of 41 AE 11 y. Sixteen patients were assigned to OLS and 14 to placebo. MEASUREMENTS: Dual energy X-ray absorptiometry (DXA) measurements of bone mineral and body composition included total bone mineral content (TBMC), total bone mineral density (TBMD), lumbar spine BMC and BMD, forearm BMC and BMD, fat mass (FM), fat free-mass (FFM), percentage fat mass (FM%) as well as a DXA estimate of the body weight. Body composition (FM, FFM and FM%) was estimated by total body potassium (TBK). Indices of calcium metabolism and bone turnover included serum values of ionized calcium (Ca ), iPTH (parathyroid hormone), alkaline phosphatase, 25(OH)-vitamin D, 1,25(OH) 2 vitamin D and osteocalcin as well as fasting urinary ratios of hydroxyprolineacreatinine and Caacreatinine (fU-OHpracreat, fUCaacreat). RESULTS: There were no signi®cant differences between OLS and placebo groups as to any of the body composition variables (FFM, FM, FM%) at baseline or after 1 y treatment. Weight loss was of 11.2 AE 7.5 kg in the OLS group and 8.1 AE 7.5 kg in the placebo group (NS). The changes in FM and FM% were signi®cant in both groups determined by DXA as well as by TBK, but the group differences between these changes were not signi®cant. The composition of the weight loss was approximately 80% fat in both groups. FFM only changed signi®cantly by DXA in the OLS group (71.3 kg), but the difference from the placebo group was not signi®cant. Forearm BMD in both groups, forearm BMC in the OLS group and TBMD in the placebo group fell discretely but signi®cantly, but there were no signi®cant group differences between the OLS and the placebo-treated group. All biochemical variables except s-osteocalcin changed signi®cantly after 1 y in the OLS group, disclosing a pattern of an incipient negative vitamin D balance, a secondary increase in PTH-secretion, and an increase in bone turnover with the emphasis on an increase in resorption parameters (fU-OHpracreat, fUCaacreat). In the placebo group, only s-25(OH)vitamin D and fUOHpracreat changed signi®cantly, but the pattern was also that of a deteriorated vitamin D status and an increase in PTH levels and bone turnover. The only biochemical variable which was signi®cantly different between OLS and placebo groups after one year was the fU-OHpracreat ratio, which increased from 12.0 to 20.1 in the OLS group but only from 10.9 to 13.2 in the placebo group. CONCLUSION: One year's treatment with OLS induces a lipid malabsorption which enhances a dietary weight loss without any signi®cant deleterious effects on body composition. OLS induces a relative in...

show abstract

“…17 ± 20 (2) Measurement of total body potassium (TBK) by counting the naturally occurring 40 K in a whole body counter. 20,21 TBK has a constant ratio to the FFM.…”

Section: Methodsmentioning

confidence: 99%

Influence of orlistat on bone turnover and body composition

2001

View full text Add to dashboard Cite

show abstract

“…Total body potassium was measured in a whole body counter, 14 and lean body mass calculated using the assumption of a potassium content of 68.1 mEq/kg lean body mass. Fat mass was calculated by subtracting the lean body mass from body weight.…”

Section: Body Compositionmentioning

confidence: 99%

Mortality associated with body fat, fat-free mass and body mass index among 60-year-old Swedish men—a 22-year follow-up. The study of men born in 1913

et al. 2000

View full text Add to dashboard Cite

OBJECTIVE: To describe differences in the 22 y mortality risk associated with body mass index (BMI), body fat or fatfree mass, in order to examine if the differential health consequences of fat and fat-free mass may be responsible for elevated mortality rates at both high and low BMI. DESIGN: Prospective cohort study, a 22 y follow-up. SETTING: General community. The study of men born in 1913, Gothenburg. SUBJECTS: 787 men aged 60 y. MAIN OUTCOME MEASURES: Number and time of total deaths from 1973 to 1995. RESULTS: The risk of dying was a linear function of percentage fat and fat-free mass, and increased from a relative risk of 1.00 in men belonging to the lowest ®fth to 1.4 (95% con®dence interval 1.11 ± 1.99) in men in the highest ®fth of percentage fat mass. For BMI the lowest risk was observed for men belonging to the middle ®fth of BMI. When the relative risk was set at 1.00 for subjects belonging to the middle ®fth of BMI the risk associated with the low BMI ®fth was 1.3 (95% con®dence interval 0.94 ± 1.68) and that with the highest ®fth was 1.5 (95% con®dence interval 1.09 ± 1.96). Analyses including both body fat and fat-free mass showed that total mortality was a linear increasing function of high fat and low fat-free mass. CONCLUSION: The apparent U-shaped association between BMI and total mortality may be the result of compound risk functions from body fat and fat-free mass.

show abstract

“…Two of the former investigations (Poehlman et al, 1990 used ANCOVA with FFM as the covariate and the others matched the trained and untrained for age and FFM (Nichols et al, 1990;Poehlman et al, 1992a). The study by Lundholm et al, 1986 on ten well-trained (69.2 AE 6.0 y) and ten untrained males (all 71 y) reported a signi®cant difference in absolute basal metabolic rate (BMR) but this disappeared when BMR was indexed to whole body potassium from which the FFM can be estimated (Forbes et al, 1961).…”

Section: Discussionmentioning

confidence: 99%

Resting metabolic rate, body composition and aerobic fitness comparisons between active and sedentary 54 –71 year old males

et al. 1999

View full text Add to dashboard Cite

Objective: To test the hypothesis that 55±70 y old male longterm exercisers (LE) have higher resting metabolic rates (RMR) than longterm nonexercisers (LNE).Design: A power analysis demonstrated that this cross-sectional study required 12 subjects per group to detect a 10% RMR difference (kJ Á kg FFM 71 Á d 71 ) between the LE and LNE (power 0.8; a 0.05). Subjects: Twelve LE ( " AE sXdX; 63.5 AE 3.4 y; 1.75 AE 0.06 m; 69.01 AE 8.24 kg; 20.4AE 4.9 %BF) and 12 LNE (63.6 AE 5.6 y; 1.72 AE 0.07 m; 79.44 AE 12.4 kg; 29.6 AE 4.4 %BF) were recruited from advertisements placed in a newspaper and on university and community noticeboards. Interventions: Measurements were conducted for: RMR using the Douglas bag technique; body composition via a four compartment model which is based on determination of body density, total body water and bone mineral mass; and aerobic ®tness using a submaximal work test on a cycle ergometer. Results: The LE (93.00 AE 7.16 kJ Á kg 71 Ád 71 ) registered a signi®cantly greater (P 0.04) RMR than the LNE (84.70 AE 11.23 kJ Á kg 71 Ád 71 ) when energy expenditure was expressed relative to body mass, but this difference disappeared (P 0.55) when the data were corrected for the non-zero intercept of the graph of RMR (MJ/d) against body mass. ANCOVA with FFM as the covariate also indicated that the RMR (MJ/d) difference between the groups was not statistically signi®cant (P 0.28). The adjusted means for the LE and LNE were 6.39 and 6.62 MJ/d, respectively. Conclusions: There are no RMR (MJad) differences between LE and LNE 54±71 y old males when statistical control is exerted for the effect of FFM and the higher value of the former group for RMR normalised to body mass disappears when this ratio is corrected for statistical bias. Sponsorship: This study was supported by a joint grant from the Flinders University of South Australia and CSIRO (Australia).

show abstract

Estimation of Total Body Fat from Potassium-40 Content

Cited by 296 publications

References 8 publications

Influence of orlistat on bone turnover and body composition

Influence of orlistat on bone turnover and body composition

Mortality associated with body fat, fat-free mass and body mass index among 60-year-old Swedish men—a 22-year follow-up. The study of men born in 1913

Resting metabolic rate, body composition and aerobic fitness comparisons between active and sedentary 54 –71 year old males

Contact Info

Product

Resources

About