Lipid forms

Lipids come in three main forms: triglycerides, which store energy and make up most dietary fat; phospholipids, which build cell membranes; and sterols such as cholesterol, which make hormones and bile. Each plays a different role in health.

What is it?

Triglycerides are three fatty acids joined to glycerol, and they make up about 95 percent of the fat in food and body fat. Phospholipids have a water-loving head and fat-loving tails, which lets them form the double layer of cell membranes. Sterols have a ring structure instead of a fatty acid chain and include cholesterol (animal) and plant sterols. See Triglycerides, Phospholipids and Sterols.

What it does

1. Triglycerides store and supply energy
2. Phospholipids form cell membranes and help fats mix with water
3. Sterols make hormones, bile acids and vitamin D
4. Lipoproteins carry lipids in the blood

Food sources

Triglycerides: all cooking oils, butter, nuts and fatty foods. Phospholipids: egg yolks, soybeans, liver and peanuts. Cholesterol: egg yolks, shellfish, organ meats, meat and dairy. Plant sterols: nuts, seeds, vegetable oils, legumes and wholegrains.

Singapore food examples

1. Cooking oils and fatty foods for triglycerides
2. Eggs and soya products for phospholipids
3. Prawns, squid, organ meats and eggs for cholesterol
4. Nuts, seeds and plant oils for plant sterols

How much do I need?

There are no separate requirements for lipid forms. Singapore's guidelines on total and saturated fat apply — see Singapore's dietary guidelines for adults (HealthHub). Your cholesterol and triglyceride levels are checked by a blood test.

Low intake and deficiency

True deficiency is not seen with a normal diet, because the body makes cholesterol and phospholipids. Severe fat malabsorption can lead to low levels of fat-soluble vitamins.

Too much and safety

Too much saturated fat, trans fat and excess energy raise LDL cholesterol and triglycerides in the blood, which increases heart disease risk. Blood lipid tests (a lipid profile) show total cholesterol, LDL, HDL and triglycerides.

Absorption and bioavailability

All lipids are digested with bile and pancreatic enzymes, absorbed in the small intestine and packaged into lipoproteins to be carried in the blood.

Connection to daily life

1. Heart health: the balance of LDL, HDL and triglycerides matters more than any single food
2. Healthy ageing: regular lipid checks help catch problems early

Sources: 1. National Academies of Sciences, Engineering, and Medicine — Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005) 2. HealthHub Singapore — Recommended Dietary Allowances: https://www.healthhub.sg/well-being-and-lifestyle/food-diet-and-nutrition/recommended_dietary_allowances 3. HealthHub Singapore — Dietary guidelines for adults: https://www.healthhub.sg/well-being-and-lifestyle/food-diet-and-nutrition/dietary_guidelines_adults 4. Health Promotion Board — Singapore Food Insights Database (SG FoodID): https://www.hpb.gov.sg/healthy-living/food-and-beverage/sgfoodid/ 5. FAO/INFOODS — Food composition tables and databases: https://www.fao.org/food-composition/tables-and-databases/en/