Lipid

Lipids are formally defined as substances such as a fat, oil or wax that dissolves in alcohol but not in water. Although the term lipid is sometimes used as a synonym for fats, fats are a subgroup of lipids called triglycerides and should not be confused with the term fatty acid. Together with carbohydrates and proteins, lipids are the main constituents of plant and animal cells.

Lipids play diverse and important roles in nutrition and health. Many lipids are absolutely essential for life. However, there is also considerable awareness that abnormal levels of certain lipids, particularly cholesterol (in hypercholesterolemia) and trans fatty acids, are risk factors for heart disease amongst others.