The objective of our research project is to determine the effects of fish protein, present in fish, on insulin sensitivity in insulin-resistant human individuals, and its mechanism of action on glucose metabolism. Our hypothesis is that fish protein improves insulin sensitivity, glucose tolerance and plasma lipid profile through an improvement in a primary defect in insulin signaling in overweight and insulin-resistant subjects.

Recent data show that cod protein prevents the development of insulin resistance in rats. Dietary fish protein may also enhance insulin sensitivity in overweight insulin-resistant subjects by improving a primary defect in insulin signaling to PI 3-kinase, leading to reduced activation of the downstream effectors Akt and PKC. To determine whether this is the case, we will study the effects of fish protein on insulin sensitivity in humans, and how it improves the ability of muscles to use glucose. Such studies will help to advise individuals with insulin resistance or type 2 diabetes about eating fish.

Inclusion Criteria:

• overweight or obese (BMI between 25 and 40 kg /m2)
• waist circumference above 88 cm for women and 102 cm for men
• fasting plasma insulin above 90 pmol/L
• fasting plasma glucose below 7.0 mmol/L and 2-h plasma glucose below 11.1 mmol/L

Exclusion Criteria:

• Individuals with diagnosed diabetes or any chronic, metabolic or acute disease
• Individuals who had a major surgery within the last 3 months
• Individuals who had a significant weight loss (±10%) within the last 6 months
• Individuals taking any medication known to affect lipid or glucose metabolism
• Subjects with dietary incompatibility with fish consumption (allergy, intolerance or dislike) and/or calcium supplementation
• Smokers