1.
Isocaloric Substitution of Dietary Carbohydrate Intake with Fat Intake and MRI-Determined Total Volumes of Visceral, Subcutaneous and Hepatic Fat Content in Middle-Aged Adults.
Meisinger, C, Rospleszcz, S, Wintermeyer, E, Lorbeer, R, Thorand, B, Bamberg, F, Peters, A, Schlett, CL, Linseisen, J
Nutrients. 2019;11(5)
-
-
-
Free full text
Plain language summary
Obesity, a worldwide epidemic due to the availability of many unhealthy food options and limited physical exercise, is a known risk factor for many metabolic disorders. The aim of this study was to investigate the association of carbohydrate intake and isocaloric substitution with different types of fat as determined by magnetic resonance imaging (MRI). The study’s analysis was based on the KORA-FF4 study, the second follow-up study of the KORA Survey S4. A total of 400 individuals participated in the FF4 study, from which 283 participants were included in this analysis. Results indicate an association between fat accumulation at specific anatomic locations and macronutrient composition among the participants. The isocaloric substitution of carbohydrates with fat was associated with higher hepatic (related to the liver) fat content and visceral fat accumulation. Authors conclude that the study’s findings can contribute towards the long-lasting discussion about a diet’s optimal fat content.
Abstract
The present study investigated the association of carbohydrate intake and isocaloric substitution with different types of fat with visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) and hepatic fat content as determined by magnetic resonance imaging (MRI). Data from 283 participants (mean age 56.1 ± 9.0 years) from the MRI sub study of the KORA FF4 study were included. VAT, SAT and total body fat were quantified by a volume-interpolated VIBE-T1w-Dixon MR sequence. Hepatic fat content was determined as the proton density fat-fraction (PDFF) derived from multiecho-T1w MR sequence. Dietary intake was estimated using information provided by two different instruments, that is, repeated 24-h food lists and a food frequency questionnaire. Replacing total carbohydrates with an isoenergetic amount of total fat was significantly positively associated with VAT and hepatic fat, while there was no significant association with SAT. The multivariable adjusted β-coefficient for replacing 5% of total energy (5E%) carbohydrates with total fat was 0.42 L (95% CI: 0.04, 0.79) for VAT. A substitution in total fat intake by 5E% was associated with a significant increase in liver fat content by 23% (p-value 0.004). If reproduced in prospective studies, such findings would strongly argue for limiting dietary fat intake.
2.
Adolescent diet and subsequent serum hormones, breast density, and bone mineral density in young women: results of the Dietary Intervention Study in Children follow-up study.
Dorgan, JF, Liu, L, Klifa, C, Hylton, N, Shepherd, JA, Stanczyk, FZ, Snetselaar, LG, Van Horn, L, Stevens, VJ, Robson, A, et al
Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology. 2010;19(6):1545-56
-
-
-
Free full text
-
Plain language summary
Population and animal studies suggest that fat in the diet may have an influence on the development of breast cancer, but the results of studies in humans are inconsistent. This randomised controlled trial aimed to determine the effects of a lower-fat diet during childhood and adolescence on markers associated with breast cancer risk in adults. Female participants were initially recruited at age 8-10 years old, as part of a study to test the effects of lower-fat diets on cholesterol levels in children. The study diet limited total fat intake to 28% of calories (<8% saturated fat, <9% polyunsaturated fat, remainder monounsaturated), cholesterol was limited to 150mg/day and consumption of fibre was encouraged. The children followed the diet for 7 years, when the trial was terminated. This follow-up study was conducted 9 years later, when the participants were aged 25 to 29 years old. After adjusting for current diet, the lower-fat diet group had significantly higher oestradiol levels and bone mineral density. Progesterone concentrations and breast density did not differ between the two groups. The authors concluded that consumption of a lower-fat diet during adolescence does not appear to affect factors associated with breast cancer risk. Current diet may be more important than adolescent diet in determining hormone levels in premenopausal women.
Abstract
BACKGROUND Adolescent diet is hypothesized to influence breast cancer risk. We evaluated the long-term effects of an intervention to lower fat intake among adolescent girls on biomarkers that are related to breast cancer risk in adults. METHODS A follow-up study was conducted on 230 girls who participated in the Dietary Intervention Study in Children (DISC), in which healthy, prepubertal, 8 to 10 year olds were randomly assigned to usual care or to a behavioral intervention that promoted a reduced fat diet. Participants were 25 to 29 years old at follow-up visits. All tests of statistical significance are two-sided. RESULTS In analyses that did not take account of diet at the time of the follow-up visit, the only statistically significant treatment group difference was higher bone mineral content in intervention group participants compared with usual care group participants; their mean bone mineral contents were 2,444 and 2,377 g, respectively. After adjustment for current diet, the intervention group also had statistically significantly higher bone mineral density and luteal phase serum estradiol concentrations. Serum progesterone concentrations and breast density did not differ by treatment group in unadjusted or adjusted analyses. CONCLUSIONS Results do not support the hypothesis that consumption of a lower fat diet during adolescence reduces breast cancer risk via effects on subsequent serum estradiol and progesterone levels, breast density, or bone mineral density. It remains unclear, however, if the results are specific to the DISC intervention or are more broadly applicable. IMPACT Modest reductions in fat intake during adolescence are unlikely to lower later breast cancer risk via long-term effects on the biomarkers measured.