Energy, cell membranes, hormone synthesis and absorption of vitamins A, D, E and K.
Switzerland age 18–65: 20–35% of energy; saturated fat below 10%.
Unsaturated: olive/rapeseed oil, nuts, seeds, avocado and fish. Saturated: butter, fatty meat, coconut fat and many baked goods.
Very-low-fat diets or fat malabsorption can reduce essential fatty acids and fat-soluble vitamins.
Replacing saturated with unsaturated fats typically improves LDL cholesterol; overall quality matters more than simply “low fat”.
Dry scaly skin can occur in severe essential-fatty-acid deficiency but is nonspecific.
Fat malabsorption, very restrictive diets and parenteral nutrition increase risk.
Assess fat sources, malabsorption symptoms and fat-soluble vitamins in context.
Food first; targeted omega-3 supplementation can be useful in defined situations.
Fat is energy dense; repeated excess can promote weight gain.