Threonine Requirement in Adult Males With Crohn's Disease Using IAAO

This study is looking for men aged between 18 and 49 years old who have Crohn's disease. You'd need to be in a generally stable condition, without severe or uncontrolled inflammation that might require urgent medical changes.

To be eligible, you should have some signs of active Crohn's disease, either in previous blood tests or medical history, but without serious blockages in your gut. You also need to have kept a stable weight for at least three months and not currently be receiving nutrition through a feeding tube. You must be willing to follow the study diet and procedures.

However, you won't be able to join if your Crohn's is severely active, you're on high doses of certain steroid medications (more than 20mg per day), or if you've recently lost a lot of weight. Other reasons for not being suitable include drinking a lot of coffee (more than 2 cups per day) or alcohol (more than one drink per day), or if you find it hard to stick to study procedures or diets.

If you decide to take part, you'll first visit The Hospital for Sick Children in Toronto for a 'pre-study assessment.' This visit will take about 3 hours and will happen after you've fasted (not eaten) for 10 hours. During this assessment, we'll measure your height, weight, body composition (fat and muscle), and energy use while resting. We'll also ask about your medical history and take a fasting blood sample. This information helps us plan your specific diet for the study.

The main part of the study involves three separate 3-day periods. For each period, you'll spend two days adjusting to a special diet. During these two 'adaptation days,' you'll only consume lactose-free milkshakes and protein-rich cookies provided by the study, along with water, clear tea, or clear coffee. On the third day, called the 'study day,' you'll continue with specially prepared liquid meals and protein-free cookies, provided every hour for eight hours. Throughout this day, we'll collect breath and urine samples at specific times to measure how your body uses threonine. You'll also receive a daily multivitamin.

On the 'study day,' one of your meals will involve a special measurement of your breath for about 20 minutes to see how much carbon dioxide your body produces. Please remember, you can choose to leave the study at any time, for any reason, particularly if you have trouble with the diet.