Blood Cholesterol Response Study

Would you like to participate in one of our research projects looking into reducing the saturated fat intake of people who suffer with raised blood cholesterol? You can do this by joining a clinical study at our specialist centre in Guildford.

An aim of this study is to increase understanding of the metabolic factors that determine the variable blood cholesterol response to saturated fat. This will enable us to tailor dietary advice to individuals who are at the highest risk of developing heart disease, who stand to gain the greatest health benefit from eating less saturated fat.  

The type of fat that we eat plays an important role in the development of heart disease. Diets high in saturated fats (found mostly in animal products such as meat and dairy foods) are related to greater levels of blood cholesterol which increases the risk of heart disease. As a result, reducing intake of saturated fat has been the cornerstone of dietary guidelines to prevent heart disease for over 30 years. However, the effect of saturated fat intake on blood cholesterol levels (and thus risk of heart disease) is highly variable between individuals. Very little is known about the metabolic factors that determine this variability in blood cholesterol between individuals, and the different ways people process saturated fat and cholesterol in the body.

We are currently looking for healthy middle-aged men, aged 30-65, who should be capable of modifying their diet in order to change their intake of saturated fat, so that we can measure the effect of these changes on blood cholesterol. Suitable volunteers should be non-smokers, who drink no more than 14 units of alcohol per week, and who do not undertake regular vigorous exercise or fitness training on more than 3 occasions per week. Men who will not be able to take part in the study include those with diabetes, heart disease (previous stroke or heart attack), kidney, bowel or liver diseases or hormone abnormalities. We must also exclude men who are taking certain types of medication (e.g. drugs from your GP for high blood pressure, high blood fats, inflammatory conditions and depression), or dietary supplements, antibiotics in the last 3 months or who are actively trying to lose or who have lost more than 3kg of weight in the last 6 months.

You will be screened over the telephone in the first instance to assess your suitability and to be advised of all other restrictions; if you wish to participate and the results from the telephone screen identify you as suitable, you will be invited to the centre for a screening visit. For the initial visit all participants must bring in their passport.

Participant Requirements 


To be eligible to take part you must be:

  • You must be a male aged between 30-65 years
  • You must have a BMI between 19 and 32 kg/m2
  • You must not smoke
  • You must have no medical history of MI or stroke in the past 12 months
  • You must not have diabetes or other endocrine disorders
  • You must not have taken medication for hyperlipidaemia (e.g. statins) or prescribed antibiotics within the last three months
  • You must have no history of alcohol abuse,
  • You must not be planning a weight reducing regime or taking any dietary supplements known to influence lipids/gut microbiota (eg. plant stanols and prebiotics); or have any other unusual medical history or diet and lifestyle habits or practices that would preclude you from  participating in a dietary study
  • You must attend your screening and all subsequent study appointments fasted (‘Fasted’ means not having eaten or drunk anything, other than water, from 8pm the night before).
  • You must avoid any strenuous exercise, and alcohol consumption 24 hours before your screening visit and subsequent study visits

The study will last for approximately 18 months, but your involvement would only be for 8 weeks (2 x 4 week diets) from the start of the first diet.  Before this, you will be asked to attend an initial Screening visit (approximately 1h) followed by 3 Study visits (approximately 1h) at Surrey Clinical Research Centre (SCRC). During the screening visit you will be seen by one of the Research Centre’s doctors; a full explanation of the study will be given, you will go through the consent process and you will be asked to give details of your medical history during the medical screening. At all visits (& screening) you will be required to come to the SCRC in an unfed, ‘fasted’ state (not having eaten or drunk anything other than water from 8pm the night before your visit after consuming the evening meal provided by the researchers). During each study visit, your weight, waist and hip circumference, blood pressure and body composition measurements will be taken. After the measurements have been performed, we will also take a blood sample of 30 ml (volume equivalent to two tablespoons) from you.

At your first study visit (week 0) and second study visit (week 4), we will give you detailed instructions on how to incorporate the assigned cooking oils, spreads and snacks into your diet. You will also be given the opportunity at these visits to ask any questions or discuss any problems encountered with the study diet.  Prior to each visit, you will be asked to collect a fasted spot urine sample and stool sample into containers which we will provide you with. You should bring the container with you when you visit the SCRC. Stool and urine samples are optional. Each study visit to the SCRC should take approximately 1 hour, after which, you will be provided with a light breakfast. You will also be asked to complete a 4-day diet diary on 3 occasions (run-in period, weeks 4 and 8).



Inconvenience Allowance 

You will be remunerated for your time and travel with £120 on full completion of the study. We will also re-numerate you for the optional stool (£20) and urine (£10) samples, should you consent to provide these; the total re-numeration available is £150.

Interested in taking part? 

Already registered as a participant with us                  New participant application form

If you have already registered with us or have previously taken part in a study at the CRC please click "already registered" to express your interest. If you have not previously registered please click "new participant application form".

More Information? 

If you would like more information under no obligation, or are interested in taking part, please contact the Clinical Research Recruitment team on: Freephone 0800 269 847, by email or, if you have not done so already, register you interest on

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