Fructose and Ethnic Differences Study (FED Study)

Overview

In the UK, people of black West African and Caribbean's tend to have healthier blood cholesterol and blood fat levels, as well as lower incidence of heart disease/heart attack. But rates of heart disease are now rising in young African-American populations with diabetes, for the first time exceeding the rate in their white European-American peers. One possible culprit is the increasing consumption of fructose which can lead to high blood fat levels. Fructose is a natural sugar found in fruits and table sugar but is also used the food industry as an ingredient and sweetener. Because fructose intakes are lower in the UK than in North America we are studying the effect of fructose intake in UK black West African and Caribbean people, to understand if fructose intake is indeed a reason for these ethnic differences.

The overall nature of this study is to conduct an investigation into the metabolic effects of acute high fructose versus high glucose feeding in people of Black African (BA) compared to age and BMI-matched control subjects of White-European (WE) origin . The research question of our study is: do people of BA metabolise fructose differently than people of WE when challenged with a high sugar diet? Therefore, our specific aims are to determine the following in both people of BA and WE consuming both high fructose and high glucose meals: 1) the postprandial pattern of blood insulin, glucose, triglyceride and cholesterol concentrations; 2) ambulatory blood pressure measures during the postprandial period and 4) postprandial and 0-24-hour fasted serum and red blood cell membrane cholesterol and non-cholesterol sterol concentrations. Potential participants will attend the scheduled screening session where the requirements of participation will be described and the participants will be given an opportunity to ask any questions they may have. Those still willing to participate will sign the informed consent form before the screening assessment is performed. Screening will require a fasted blood sample to be taken as well as a brief questionnaire to ascertain ethnicity (self-declared), medications and health status. An assessment of weight, height and waist circumference will also be taken to confirm they meet the inclusion criteria. It is expected that the results of the screening blood sample will be available within 1-2 weeks. Those participants meeting the inclusion criteria will be contacted and scheduled for the first study visit. Those not meeting the criteria will be notified by their preferred means of contact, a copy of their results will be provided. Prior to attending participants treatment order will be randomized. Participants will report to the Metabolic Research Unit (MRU) at 08.00 following an overnight fast. A catheter will be inserted into an antecubital vein for collection of blood samples and a baseline blood sample collected at this time. Participant will be asked to undertake minimal physical activity during the remainder of the study period. A breakfast meal will be given at 0min, the lunch meal at 240min and meals will be consumed within 15 minutes. Participants will be fitted with a portable continuous blood pressure and heart rate monitor (arteriograph) and instructed on what to expect as it functions. Further blood samples will be taken at -30, -15, 0, 15, 30, 45, 60, 90, 120, 180, 240, 300, 360, 420min and at 24hrs (1440min, fasted). The energy content of the meals will be the estimated energy requirements of the participant (to the nearest 100kcals), with 20% of total daily energy coming from glucose or fructose. The glucose or fructose will be given dissolved water with added colour and orange/fruit flavours and provided at breakfast, lunch and supper. The remaining daily caloric requirement for each participant will be given a standardized evening meal to take away and consume at home.