Free and esterified fatty acid and cholesterol synthesis in adult malesand its effect on the doubly-labelled water method

P Haggarty, P Shetty, S Thangam, S Kumar, A Kurpad, J Ashton, E Milne, C Earl

    Research output: Contribution to journalArticle

    8 Citations (Scopus)

    Abstract

    The purpose of the present study was to estimate whole-body fatty acid and cholesterol synthesis in weight-stable adults and to determine the likely effect on the doubly-labelled water (DLW) method for measuring energy expenditure. Synthesis was measured by H-2 incorporation over 14 d in six adult males in approximate energy balance following noradrenaline infusion to maximize mobilization of free fatty acid from adipose tissue. The inter-individual variation in synthesis rates was large and in one subject the proportion of free fatty acid synthesized was ten times that of the mean of the rest of the group; the fasting concentration of esterified fatty acid in this subject was five times that of the rest of the group indicating likely violation of the assumptions underlying the calculation of whole-body synthesis. After 14 d of labelling in the other five subjects, 0.9 (sem 0.3) % of the circulating free fatty acid, 9.3 (sem 3.0) % of the esterified fatty acid, 14.6 (sem 2.4) % of the free cholesterol and 28.3 (sem 3.7) % of esterified cholesterol had been synthesized de novo. A high rate of synthesis correlated with a low pre-dose H-2 abundance both within and between lipid classes suggesting that natural H-2 abundance variations in some lipid classes may be used to determine their metabolic origin. Whole-body synthetic rates were 8 g/d for fatty acid and 0.3-0.5 g/d for cholesterol. These values correspond to very small errors on DLW-derived estimates of CO2 production; -2.5 litres/d for fatty acid and -0.1 to -0.2 litres/d for cholesterol. These results, obtained in subjects typically consuming a diet with a lower fat and cholesterol content that the typical Western diet, suggest that the DLW method is unlikely to be affected by fatty acid and cholesterol synthesis in subjects in energy balance consuming a typical Western diet.

    Original languageEnglish
    Pages (from-to)227-234
    Number of pages8
    JournalBritish Journal of Nutrition
    Volume83
    Publication statusPublished - 2000

    Keywords

    • deuterium
    • deoubly-labelled water
    • energy expenditure
    • lipid synthesis
    • HUMAN ADIPOSE-TISSUE
    • DEUTERIUM INCORPORATION
    • PLASMA-CHOLESTEROL
    • LIPOGENESIS

    Cite this

    Haggarty, P., Shetty, P., Thangam, S., Kumar, S., Kurpad, A., Ashton, J., ... Earl, C. (2000). Free and esterified fatty acid and cholesterol synthesis in adult malesand its effect on the doubly-labelled water method. British Journal of Nutrition, 83, 227-234.

    Free and esterified fatty acid and cholesterol synthesis in adult malesand its effect on the doubly-labelled water method. / Haggarty, P ; Shetty, P ; Thangam, S ; Kumar, S ; Kurpad, A ; Ashton, J ; Milne, E ; Earl, C .

    In: British Journal of Nutrition, Vol. 83, 2000, p. 227-234.

    Research output: Contribution to journalArticle

    Haggarty, P, Shetty, P, Thangam, S, Kumar, S, Kurpad, A, Ashton, J, Milne, E & Earl, C 2000, 'Free and esterified fatty acid and cholesterol synthesis in adult malesand its effect on the doubly-labelled water method', British Journal of Nutrition, vol. 83, pp. 227-234.
    Haggarty, P ; Shetty, P ; Thangam, S ; Kumar, S ; Kurpad, A ; Ashton, J ; Milne, E ; Earl, C . / Free and esterified fatty acid and cholesterol synthesis in adult malesand its effect on the doubly-labelled water method. In: British Journal of Nutrition. 2000 ; Vol. 83. pp. 227-234.
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    T1 - Free and esterified fatty acid and cholesterol synthesis in adult malesand its effect on the doubly-labelled water method

    AU - Haggarty, P

    AU - Shetty, P

    AU - Thangam, S

    AU - Kumar, S

    AU - Kurpad, A

    AU - Ashton, J

    AU - Milne, E

    AU - Earl, C

    PY - 2000

    Y1 - 2000

    N2 - The purpose of the present study was to estimate whole-body fatty acid and cholesterol synthesis in weight-stable adults and to determine the likely effect on the doubly-labelled water (DLW) method for measuring energy expenditure. Synthesis was measured by H-2 incorporation over 14 d in six adult males in approximate energy balance following noradrenaline infusion to maximize mobilization of free fatty acid from adipose tissue. The inter-individual variation in synthesis rates was large and in one subject the proportion of free fatty acid synthesized was ten times that of the mean of the rest of the group; the fasting concentration of esterified fatty acid in this subject was five times that of the rest of the group indicating likely violation of the assumptions underlying the calculation of whole-body synthesis. After 14 d of labelling in the other five subjects, 0.9 (sem 0.3) % of the circulating free fatty acid, 9.3 (sem 3.0) % of the esterified fatty acid, 14.6 (sem 2.4) % of the free cholesterol and 28.3 (sem 3.7) % of esterified cholesterol had been synthesized de novo. A high rate of synthesis correlated with a low pre-dose H-2 abundance both within and between lipid classes suggesting that natural H-2 abundance variations in some lipid classes may be used to determine their metabolic origin. Whole-body synthetic rates were 8 g/d for fatty acid and 0.3-0.5 g/d for cholesterol. These values correspond to very small errors on DLW-derived estimates of CO2 production; -2.5 litres/d for fatty acid and -0.1 to -0.2 litres/d for cholesterol. These results, obtained in subjects typically consuming a diet with a lower fat and cholesterol content that the typical Western diet, suggest that the DLW method is unlikely to be affected by fatty acid and cholesterol synthesis in subjects in energy balance consuming a typical Western diet.

    AB - The purpose of the present study was to estimate whole-body fatty acid and cholesterol synthesis in weight-stable adults and to determine the likely effect on the doubly-labelled water (DLW) method for measuring energy expenditure. Synthesis was measured by H-2 incorporation over 14 d in six adult males in approximate energy balance following noradrenaline infusion to maximize mobilization of free fatty acid from adipose tissue. The inter-individual variation in synthesis rates was large and in one subject the proportion of free fatty acid synthesized was ten times that of the mean of the rest of the group; the fasting concentration of esterified fatty acid in this subject was five times that of the rest of the group indicating likely violation of the assumptions underlying the calculation of whole-body synthesis. After 14 d of labelling in the other five subjects, 0.9 (sem 0.3) % of the circulating free fatty acid, 9.3 (sem 3.0) % of the esterified fatty acid, 14.6 (sem 2.4) % of the free cholesterol and 28.3 (sem 3.7) % of esterified cholesterol had been synthesized de novo. A high rate of synthesis correlated with a low pre-dose H-2 abundance both within and between lipid classes suggesting that natural H-2 abundance variations in some lipid classes may be used to determine their metabolic origin. Whole-body synthetic rates were 8 g/d for fatty acid and 0.3-0.5 g/d for cholesterol. These values correspond to very small errors on DLW-derived estimates of CO2 production; -2.5 litres/d for fatty acid and -0.1 to -0.2 litres/d for cholesterol. These results, obtained in subjects typically consuming a diet with a lower fat and cholesterol content that the typical Western diet, suggest that the DLW method is unlikely to be affected by fatty acid and cholesterol synthesis in subjects in energy balance consuming a typical Western diet.

    KW - deuterium

    KW - deoubly-labelled water

    KW - energy expenditure

    KW - lipid synthesis

    KW - HUMAN ADIPOSE-TISSUE

    KW - DEUTERIUM INCORPORATION

    KW - PLASMA-CHOLESTEROL

    KW - LIPOGENESIS

    M3 - Article

    VL - 83

    SP - 227

    EP - 234

    JO - British Journal of Nutrition

    JF - British Journal of Nutrition

    SN - 0007-1145

    ER -