Study Into Genetic Influence on Cholesterol Response to Dietary Fat

University of Reading88 enrolled

Overview

Cardiovascular disease (CVD) is recognised as one of the main causes of death in the western world. LDL- cholesterol ('bad' cholesterol) and other lipids (fats) are important CVD risk factors. Apolipoprotein E (apoE) is an important transporter of fats in the blood. ApoE comes in E2, E3 and E4 forms, depending on your genetic make up. Approximately 60% of the UK population are E3/E3, 25% E4 carriers and 15% E2 carriers. There is some evidence to suggest that an E4 genotype may put you at modestly higher risk of CVD. Furthermore although very inconclusive previous studies have suggested that E4 individuals are slightly more sensitive to the LDL-cholesterol modifying effects of dietary fats (saturated fat, total fat, fish oil) showing slightly, greater reductions when low levels of these fat are consumed, and greater increases when high levels of these fat are consumed. Therefore, the aims of the Satgene study is to examine the impact of modifications in dietary total fat and saturated fat intakes, alone and in combination with fish oil supplement on LDL-cholesterol and other blood lipids, in individuals with an E3 and E4 genotype. The levels of total fat and saturated fat used in the current study are within the range observed in a typical UK population.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

PREVENTION

Masking

NONE

Enrollment

Conditions

Cardiovascular Diseases

Low fat dietDIETARY_SUPPLEMENT

Subjects were asked to consume a low fat diet for 8 weeks. Composition: 28% energy from fat, 8% energy from saturated fat, 55% energy from carbohydrate. Subjects were provided with low fat spread, cooking oil and snacks and asked to consume these in place of normally eaten equivalent foods. Subjects were asked to consume two extra portions of carbohydrate per day (e.g. two slices of bread, equivalent to 35g carbohydrate) and to consume low fat dairy products. Subjects also consumed 2g control oil per day during this period. Control oil comprised palm olein and soybean oil.

Hgih saturated fat dietDIETARY_SUPPLEMENT

Subjects were asked to consume a high saturated fat diet for 8 weeks. Composition: 38% energy from fat, 18% energy from saturated fat, 45% energy from carbohydrate. Subjects were provided with spread, cooking oil and snacks and asked to consume these in place of normally eaten equivalent foods. Subjects were asked to consume one less portion of carbohydrate per day (e.g. one slice of bread and to consume full fat dairy products. Subjects also consumed 2g control oil per day during this period. Control oil comprised palm olein and soybean oil.

High saturated fat dietDIETARY_SUPPLEMENT

Subjects were asked to consume a high saturated fat diet for 8 weeks. Composition: 38% energy from fat, 18% energy from saturated fat, 45% energy from carbohydrate. Subjects were provided with spread, cooking oil and snacks and asked to consume these in place of normally eaten equivalent foods. Subjects were asked to consume one less portion of carbohydrate per day (e.g. one slice of bread and to consume full fat dairy products. Subjects also consumed 6g DHA-rich oil per day during this period providing 3g DHA.

Eligibility

Sex: ALLMin age: 35 YearsMax age: 70 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: Men \& women 35-70 years BMI 20-32 kg/m2 Haemoglobin (anaemia): 12.5-18.0g/l (men) and \> 11.5-16g/l (women) Gamma GT (liver function) (\< 80 IU/l), Triglyceride (between 1-4 mmol/l), Plasma total cholesterol (4.5-8 mmol/l) Glucose (World Health organisation recommend \<7 mmol/L). Exclusion Criteria: * Females who are breast feeding, may be pregnant, or if child-bearing potential are not taking effective contraceptive precautions * Likely to alter oral contraceptive or HRT usage during the course of the study * Blood Pressure \> 160/100 mm Hg (UK guidelines for stage 2 hypertension) * Had suffered a myocardial infarction or stroke in the previous 12 months * Hypertensive medication * Diabetics type I and II * Any volunteers on a weight reducing diet, or vegan/vegetarians as study requires consumption of dairy products and fish oils * On high dose fish oil supplements (\> 1g EPA + DHA per day) * Elevated lipids requiring medication such as statins, fibrates, gall bladder problems or other abnormalities of fat metabolism * Subjects not willing to make the necessary dietary changes during the study * Subjects drinking excessive alcohol (UK recommendations/wk currently for men are, no more than 21 units of alcohol per week or more than four units in any one day. For women, no more than 14 units of alcohol per week or more than three units per day). * Subjects who train at a high level, or attend more than 3 hours organised exercise classes per week

Outcomes

Primary Outcomes

Change in low density lipoprotein cholesterol (LDL-C)

Time frame: 0, 8, 16, and 24 weeks

Secondary Outcomes

Change in arterial stiffness

Arterial stiffness is a measure of vascular reactivity. This was assessed by Digital Volume Pulse using Pulse Trace PCA2 Machine (Micromedical, UK)