Participants satisfying the inclusion criteria will be invited to the Oxford Centre for
Clinical Magnetic Resonance Research (OCMR), to measure the amount of fat within their liver
and heart using magnetic resonance imaging and spectroscopy (MRI/S). Then on a separate day,
within one week of having their liver and heart fat content measured, participants will come
into the Clinical Research Unit (CRU) at the Oxford Centre for Diabetes Endocrinology and
Metabolism (OCDEM) for a 'postprandial study day' after an overnight fast. Participants will
be asked to avoid excessive exercise and alcohol for 24 hours prior to the study. The day
prior to and over the course of the 'study day' participants will be asked to drink some
'heavy water' ((2H2O) CK Isotopes Limited). The amount of 'heavy water' a volunteer will have
to consume is 3g heavy water per kg body water, which will achieve a plasma water enrichment
of 0.3%. Once participants arrive at OCDEM the researchers will make some anthropometric
measurements (e.g. weight, height, waist circumference etc.), collect a urine sample, and
place a small plastic tube (cannula) into a vein on the forearm, from which they will take
blood samples. A second cannula will also be placed into a large vein in the elbow crease of
the opposite arm. Sequential blood samples will be collected by the researchers at regular
intervals for a period of up to 8 hours from placing the first cannula. After the first blood
samples have been taken (Time -30) the researchers will start pumping fat labelled with
special atoms (stable isotopes from CK Isotopes Limited) into the other cannula. After
approximately 30 minutes of infusion, a second blood sample (time 0) will be taken, after
which participants will be fed a standardised test meal which will consist of cereal and
semi-skimmed milk and a "fatty" chocolate drink. The fatty chocolate drink is made with a
blend of oils and will be labelled with a stable isotope (from CK Isotopes Limited). The use
of the stable isotopes in small doses is considered to be completely harmless (it is not
radioactive). Once the test meal is consumed, the volunteer is free to rest on a bed or in a
chair, as they prefer, until the experiment is finished, up to 8 hours. After giving the
stable isotopes, blood and breath samples will be taken initially every 30 minutes for the
first two hours and then every 60 minutes up until the end of the study day (6 hours post
breakfast). The researchers would take blood samples through the cannula in the vein, and at
each time point would take approx. 25ml of blood. The most blood taken in total over the day
would be 250ml or approximately 1/2 of a pint.
Three hours after consumption of the test breakfast meal the researchers will take two
adipose tissue biopsies. The first biopsy will be taken from the fat just under the skin in
the abdomen (tummy) and the second biopsy will be taken from the gluteal (buttock) region.
There will be numbing of the skin and fat tissue as a local anaesthetic (1% lignocaine) is
used prior to all biopsies. The choice as to whether or not to undergo biopsies will be given
to participants on the study day. At some point during the day a dual energy X-ray
absorptiometry (DEXA) scan will be performed. The DEXA scan will measure the total amount of
fat (adipose tissue) along with the amount of adipose tissue in specific depots (e.g. upper
body, lower body, visceral etc.). When all of the samples have been taken and the
measurements are finished, the researchers would take out the plastic tubes, and give the
participant something further to eat and drink before making sure they can get home, usually
by providing them with a taxi. Participants will also be provided with the sulforaphane
capsules to be ingested over the following 3-week period, and guidelines as to when to take
supplements. Participants will be asked to maintain their habitual diets during the
intervention phase, which will be assessed via the completion of food diaries where all foods
and beverages consumed on 3 days a week (two week and one weekend day) each week of the 3
week intervention phase. A member of the research team will be in regular contact with
participants via email throughout the intervention phase in an attempt to maintain
compliance. Following the 3-week intervention phase the volunteer's liver and heart fat
content will again be measured using MRI/S at OCMR, then on a separate day, within one week
of having their liver and heart fat content measured, participants will come into the CRU at
OCDEM for a second 'study day' after an overnight fast. The second 'study day' will be
identical to the first study day described above.
