Browsing by Subject "LDL-cholesterol"

Background: ​In adults, vegetarian and vegan diets have been associated with decreased cardiovascular disease (CVD) risk. At the same time, lower plasma LDL-concentrations are reported in vegans than in omnivores. Classification of a vegetarian diet can be challenging, as the diets vary in the degree and categories of the avoided food products. Recently, plant-based diet indices (PDI), such as the provegetarian food pattern, have been introduced as​ a priori ​method to study vegetarianism as a continuum. Plant-based dietary indices weigh positively foods derived from plant sources, whereas animal foods are weighed negatively. Greater adherence to PDI has been associated with lower CVD mortality and lower incidence of coronary heart disease (CHD). Meanwhile, little is known about the associations of plant-based eating and the risk of CVD in children. Aims:​ The aim of this thesis is to study plant-based eating as a continuous phenomenon in a group of Finnish preschoolers. Furthermore, the focus is on the animal source energy and its associations with dietary intakes, and cholesterol and bile acid metabolism. Materials and methods: ​In this thesis, the data from the cross-sectional MIRA Helsinki Study is used. In 2017, City of Helsinki started a pilot project, in which a vegan food option was offered in municipal daycare. At the same year, MIRA Helsinki Study was started to examine the nutritional status of children following a vegan diet. Altogether 42 children, aged 1–7-years, participated. At daycare, 18 of the children consumed a vegan diet, whereas 24 were omnivores. However, these diet categories did not apply to the child’s diet outside daycare. Children’s diet was assessed with 4-day food records and with food frequency questionnaires (FFQs). Anthropometric measurements were taken and fasting blood samples collected. Blood samples were analysed with standard laboratory tests. Gas-liquid chromatography (GLC) and liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) methods were used to examine serum cholesterol metabolism biomarkers and bile acids, respectively. For each food item (n=719) in the food record data, the weight proportion of animal content was estimated. The animal-origin energy content of each food item was calculated by multiplying the known energy content of the food item with the aforementioned score. The proportion of animal source energy (ASE) per subject across the 4-day food record was calculated by dividing the energy derived from animal sources with total energy intake. The correlations of ASE proportion with dietary intakes and surrogate markers of cholesterol and bile acid metabolism were investigated with the Pearson correlation analysis. A multiple linear regression model was used to test whether the ASE proportion explained the plasma LDL-cholesterol (LDL-C) concentration when controlling for the child’s sex and maternal education. In addition, the associations between the ASE proportion and serum concentrations of 20 bile acid variables were examined with the Pearson correlation coefficient. The Benjamini-Hochberg procedure was used to correct for multiple analyses. Results: ​Among all of the participants, ASE proportions ranged from 0.00 to 0.52, with a median value of 0.275 (that is, 27.5% of total energy derived from animal sources).​ ​I​ntake of animal source energy correlated positively with SAFA (r=0.815, p<0.000), cholesterol (r=0.707, p<0.000) and protein (r=0.493, p<0.001) intakes. There was a strong negative correlation between the ASE proportion and fibre intake (r=–0.836, p<0.000). In a linear regression model, adjusted for child’s sex and mother’s educational level, the model explained 44% (p<.000) of the variance in the plasma LDL-C concentration. Every 0.1 increase in the ASE proportion (10E% increase in energy derived from animal sources) was associated with a 0.32 mmol/L higher plasma LDL-C concentration. Associations of ASE proportion and cholesterol surrogate markers were present: a higher intake of ASE correlated with lower concentrations of cholesterol absorption markers. A similar negative association with ASE proportion was present for two out of four cholesterol synthesis biomarkers. In addition, the bile acid synthesis biomarker (​7α-hydroxy-4-cholesten-3-one) correlated negatively with the ASE proportion. From the 20 serum bile acid variables studied only the ratio of tauro- to glyco-conjugated bile acids was significantly associated with the ASE proportion after correcting for multiple analyses. Conclusion:​ Among the study participants, animal source energy ratio was a powerful predictor of plasma LDL-C concentrations. Dietary patterns characterised by high intake of animal source energy were less likely to meet the dietary recommendations of fatty acid (SAFA and PUFA) intake. Our results on cholesterol metabolism need to be confirmed and replicated in future studies, which should include data on absolute measurements of cholesterol synthesis and absorption.