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Dietary n-3-polyunsaturated fatty acids and energy balance in overweight or moderately obese men and women: a randomized controlled trial.

Kratz M, Callahan HS, Yang PY, Matthys CC, Weigle DS - Nutr Metab (Lond) (2009)

Bottom Line: Dietary n-3-polyunsaturated fatty acids (n-3-PUFA) have been shown to reduce body weight and fat mass in rodents as well as in humans in one small short-term study.Consistent with this finding, we also found no differences between the n-3-PUFA and control groups with regard to appetite as measured by visual analogue scale, ad libitum food intake, resting energy expenditure as measured by indirect calorimetry, diurnal plasma leptin concentrations, or fasting ghrelin concentrations.Our results suggest that dietary n-3-PUFA do not play an important role in the regulation of food intake, energy expenditure, or body weight in humans.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington, 1959 NE Pacific Street, Seattle, Washington 98195, USA. mkratz@fhcrc.org.

ABSTRACT

Background: Dietary n-3-polyunsaturated fatty acids (n-3-PUFA) have been shown to reduce body weight and fat mass in rodents as well as in humans in one small short-term study. We conducted this controlled randomized dietary trial to test the hypothesis that n-3-PUFA lower body weight and fat mass by reducing appetite and ad libitum food intake and/or by increasing energy expenditure.

Methods: Twenty-six overweight or moderately obese (body mass index 28-33 kg/m²) men and women were included, and received either a diet rich in n-3-PUFA from both plant and marine sources or a control diet. Diets were administered in an isocaloric fashion for 2 weeks followed by 12 weeks of ad libitum intake. The n-3-PUFA and control diets were identical in all regards except for the fatty acid composition. All foods were provided to subjects, and leftovers were weighed back to assess actual food intake accurately for each day of the study. This design gave us 80% power to detect a difference in weight change between the n-3-PUFA and control diet groups of 2.25 kg at an α-error level of 5%.

Results: Both groups lost similar amounts of weight when these diets were consumed ad libitum for 12 weeks [mean (SD): -3.5 (3.7) kg in the control group vs. -2.8 (3.7) kg in the n-3-PUFA group, F(₁,₂₄) = 13.425, p = 0.001 for time effect; F(₁,₂₄) = 0.385, p = 0.541 for time x group interaction]. Consistent with this finding, we also found no differences between the n-3-PUFA and control groups with regard to appetite as measured by visual analogue scale, ad libitum food intake, resting energy expenditure as measured by indirect calorimetry, diurnal plasma leptin concentrations, or fasting ghrelin concentrations.

Conclusion: Our results suggest that dietary n-3-PUFA do not play an important role in the regulation of food intake, energy expenditure, or body weight in humans.

No MeSH data available.


Related in: MedlinePlus

Diurnal plasma leptin concentrations during clinical research center (CRC) visits 1, 2, and 3 in subjects consuming the control diet (a, n = 13) or the diet rich in n-3-polyunsaturated fatty acids (b, n = 13). Blood was drawn every 30' between 0800 and 2100, and every 60' thereafter. Meals were consumed at 0800, 1200, 1730, and 2000 immediately after the respective blood draws, and subjects were requested to complete the meal within 30'. Data are expressed in % of the CRC 1 0800 value, and represent means and standard errors of the means.
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Figure 2: Diurnal plasma leptin concentrations during clinical research center (CRC) visits 1, 2, and 3 in subjects consuming the control diet (a, n = 13) or the diet rich in n-3-polyunsaturated fatty acids (b, n = 13). Blood was drawn every 30' between 0800 and 2100, and every 60' thereafter. Meals were consumed at 0800, 1200, 1730, and 2000 immediately after the respective blood draws, and subjects were requested to complete the meal within 30'. Data are expressed in % of the CRC 1 0800 value, and represent means and standard errors of the means.

Mentions: The area-under-the diurnal plasma leptin curve did not change between CRC 1 and CRC 2 in either group [time: F(1,24) = 1.927, p = 0.178; time × group: F(1,24) = 0.594, p = 0.449 in RM-ANOVA], but decreased when subjects lost weight during the ad libitum period by 450 ± 896 arbitrary units (AU) in the control group, and by 350 ± 705 AU in the n-3-PUFA group [time: F(1,24) = 6.394, p = 0.018, time × group: F(1,24) = 0.100, p = 0.754 in RM-ANOVA; Figure 2]. Fasting ghrelin concentrations in plasma increased moderately by ~7% in both groups when subjects lost weight during the ad libitum period, but were not different between the groups (Table 1). Changes in ghrelin concentrations in the 'pool'-sample reflecting the average ghrelin concentrations throughout each of the 24-hour clinic visits were similar to those observed in fasting plasma (Table 1).


Dietary n-3-polyunsaturated fatty acids and energy balance in overweight or moderately obese men and women: a randomized controlled trial.

Kratz M, Callahan HS, Yang PY, Matthys CC, Weigle DS - Nutr Metab (Lond) (2009)

Diurnal plasma leptin concentrations during clinical research center (CRC) visits 1, 2, and 3 in subjects consuming the control diet (a, n = 13) or the diet rich in n-3-polyunsaturated fatty acids (b, n = 13). Blood was drawn every 30' between 0800 and 2100, and every 60' thereafter. Meals were consumed at 0800, 1200, 1730, and 2000 immediately after the respective blood draws, and subjects were requested to complete the meal within 30'. Data are expressed in % of the CRC 1 0800 value, and represent means and standard errors of the means.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2696454&req=5

Figure 2: Diurnal plasma leptin concentrations during clinical research center (CRC) visits 1, 2, and 3 in subjects consuming the control diet (a, n = 13) or the diet rich in n-3-polyunsaturated fatty acids (b, n = 13). Blood was drawn every 30' between 0800 and 2100, and every 60' thereafter. Meals were consumed at 0800, 1200, 1730, and 2000 immediately after the respective blood draws, and subjects were requested to complete the meal within 30'. Data are expressed in % of the CRC 1 0800 value, and represent means and standard errors of the means.
Mentions: The area-under-the diurnal plasma leptin curve did not change between CRC 1 and CRC 2 in either group [time: F(1,24) = 1.927, p = 0.178; time × group: F(1,24) = 0.594, p = 0.449 in RM-ANOVA], but decreased when subjects lost weight during the ad libitum period by 450 ± 896 arbitrary units (AU) in the control group, and by 350 ± 705 AU in the n-3-PUFA group [time: F(1,24) = 6.394, p = 0.018, time × group: F(1,24) = 0.100, p = 0.754 in RM-ANOVA; Figure 2]. Fasting ghrelin concentrations in plasma increased moderately by ~7% in both groups when subjects lost weight during the ad libitum period, but were not different between the groups (Table 1). Changes in ghrelin concentrations in the 'pool'-sample reflecting the average ghrelin concentrations throughout each of the 24-hour clinic visits were similar to those observed in fasting plasma (Table 1).

Bottom Line: Dietary n-3-polyunsaturated fatty acids (n-3-PUFA) have been shown to reduce body weight and fat mass in rodents as well as in humans in one small short-term study.Consistent with this finding, we also found no differences between the n-3-PUFA and control groups with regard to appetite as measured by visual analogue scale, ad libitum food intake, resting energy expenditure as measured by indirect calorimetry, diurnal plasma leptin concentrations, or fasting ghrelin concentrations.Our results suggest that dietary n-3-PUFA do not play an important role in the regulation of food intake, energy expenditure, or body weight in humans.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington, 1959 NE Pacific Street, Seattle, Washington 98195, USA. mkratz@fhcrc.org.

ABSTRACT

Background: Dietary n-3-polyunsaturated fatty acids (n-3-PUFA) have been shown to reduce body weight and fat mass in rodents as well as in humans in one small short-term study. We conducted this controlled randomized dietary trial to test the hypothesis that n-3-PUFA lower body weight and fat mass by reducing appetite and ad libitum food intake and/or by increasing energy expenditure.

Methods: Twenty-six overweight or moderately obese (body mass index 28-33 kg/m²) men and women were included, and received either a diet rich in n-3-PUFA from both plant and marine sources or a control diet. Diets were administered in an isocaloric fashion for 2 weeks followed by 12 weeks of ad libitum intake. The n-3-PUFA and control diets were identical in all regards except for the fatty acid composition. All foods were provided to subjects, and leftovers were weighed back to assess actual food intake accurately for each day of the study. This design gave us 80% power to detect a difference in weight change between the n-3-PUFA and control diet groups of 2.25 kg at an α-error level of 5%.

Results: Both groups lost similar amounts of weight when these diets were consumed ad libitum for 12 weeks [mean (SD): -3.5 (3.7) kg in the control group vs. -2.8 (3.7) kg in the n-3-PUFA group, F(₁,₂₄) = 13.425, p = 0.001 for time effect; F(₁,₂₄) = 0.385, p = 0.541 for time x group interaction]. Consistent with this finding, we also found no differences between the n-3-PUFA and control groups with regard to appetite as measured by visual analogue scale, ad libitum food intake, resting energy expenditure as measured by indirect calorimetry, diurnal plasma leptin concentrations, or fasting ghrelin concentrations.

Conclusion: Our results suggest that dietary n-3-PUFA do not play an important role in the regulation of food intake, energy expenditure, or body weight in humans.

No MeSH data available.


Related in: MedlinePlus