Cholesterol

Cholesterol is a waxy, fat-like substance that every cell needs. The liver makes most of the cholesterol in your body, and the rest comes from animal foods. For most people, blood cholesterol is influenced more by saturated and trans fat than by the cholesterol in food.

What is it?

Cholesterol is carried in the blood by lipoproteins. LDL ("bad") cholesterol carries cholesterol to tissues and can build up in artery walls; HDL ("good") cholesterol carries it back to the liver. Roughly three quarters of the cholesterol in the body is made by the body itself, and about a quarter comes from food.

What it does

1. Is part of every cell membrane
2. Is used to make steroid hormones (oestrogen, testosterone, cortisol) and vitamin D
3. Is used to make bile acids that digest fat

Food sources

Egg yolks, organ meats such as liver, shellfish (prawns, squid), meat, poultry skin, butter and full-fat dairy. Plant foods contain no cholesterol.

Singapore food examples

1. Egg yolks
2. Prawns, squid, crab and fish roe
3. Liver, kidney, intestines and other organ meats in soups and stir-fries
4. Fatty meat, chicken skin and full-fat dairy
5. To lower LDL: oats, beans, nuts, fruit, vegetables, fish and plant oils

How much do I need?

There is no recommended intake for dietary cholesterol, and Singapore's RDA table does not list it. Many guidelines now focus on saturated and trans fat rather than a strict cholesterol limit, although people with high LDL cholesterol, diabetes or heart disease are often advised to be careful about high-cholesterol foods. A moderate egg intake fits most healthy diets — ask your doctor if your cholesterol is high. See Singapore's dietary guidelines for adults (HealthHub).

Low intake and deficiency

The body makes the cholesterol it needs, so deficiency does not occur from diet. Very low cholesterol is rare and usually due to illness or inherited disorders.

Too much and safety

High LDL cholesterol builds up plaque in arteries (atherosclerosis), raising the risk of heart attack and stroke, usually without symptoms — it is found by a blood test. Saturated fat, trans fat, excess weight, inactivity, smoking, diabetes and genes all raise risk.

To lower cholesterol: eat less saturated and trans fat, more fibre (oats, beans, fruit, vegetables), nuts, fish and plant oils, keep to a healthy weight, be active and do not smoke. Medicines such as statins are very effective when needed; do not stop them without advice.

Absorption and bioavailability

About half of dietary cholesterol is absorbed in the small intestine, and absorption varies widely between people. The liver adjusts its own production when intake changes, which is why food cholesterol has a smaller effect than saturated fat in many people. Soluble fibre and plant sterols reduce absorption.

Connection to daily life

1. Heart health: know your numbers — get a cholesterol test as advised
2. Exercise: regular activity raises HDL and lowers triglycerides — see Exercise
3. Healthy ageing: cholesterol control lowers the risk of heart disease and stroke over decades
4. Stress and sleep: poor sleep and chronic stress can influence cholesterol indirectly through diet and weight — see Sleep and Stress

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/