Lipids - Introduction

Question 1

Introduction

Answer 1

• The body of a lean healthy man is composed of roughly 16% fat, while the lipid content in severe obesity can account for up to 70% (or 57 kg) of body weight, mostly in adipocytes.
• Dietary fat intake is a hotly-debated issue and is a major point of interest in nutrition today.
• Fats are not just a source of energy. They form part of every cell and are vital for physiological and biological processes (e.g. hormone production).
• Farming and food processing have increased the amount and types of fat in human diets, most notably trans fats and vegetable oils.
  adipo= fat, cyte= cell

Question 2

The Fat Debate

Answer 2

• Fat intake has changed in recent times, most notably since fats were credited with causing heart disease.
• In the 1950s, Ancel Keys declared that eating a high saturated fat diet would increase serum cholesterol and consequently lead to heart disease. His experiments significantly changed society’s perception on fats.
• The American Heart Association (AHA) then recommended a diet low in total fat, especially saturated fat and cholesterol, and high in carbohydrates from grains, substituting animal fats for seed oils. This also resulted in the introduction of statins—one of the most profitable pharmaceutical industry drugs.

Question 3

Fat For Health

Answer 3

• Due to the association with cardiovascular disease, and the cosmetic and psychological burden of excess body fat, the role of adipocytes in the body is hugely misunderstood.
• Far from being inert, white adipose tissue (WAT) is a complex, metabolically-active endocrine tissue.
• Functions include:
  o The secretion of hormones, growth factors, enzymes and cytokines;
  o The protection of organs;
  o A form of energy storage;
  o To provide insulation to protect against temperature extremes.
  Cytokines = cell signalling proteins