Phytosterols

Phytosterols are plant compounds with a structure similar to cholesterol. When eaten in sufficient amounts, they block part of the cholesterol absorbed from food and bile, and can lower LDL cholesterol by about 6 to 15 percent.

What is it?

The main plant sterols are beta-sitosterol, campesterol and stigmasterol; plant stanols are their saturated forms. They are part of plant cell membranes. Foods naturally provide about 200 to 400 mg a day, much less than the around 2 g a day needed for a clear cholesterol-lowering effect, which is why fortified foods and supplements are used.

What it does

1. Compete with cholesterol for absorption in the gut
2. Lower LDL ("bad") cholesterol by roughly 6 to 15 percent at about 2 g a day
3. Add to the effect of a heart-healthy diet and of statin medicines

Food sources

Vegetable oils (corn, sesame, canola), nuts, seeds, wholegrains, legumes, avocado, and fortified foods such as spreads, yoghurt drinks, milk and juices.

Singapore food examples

1. Sesame seeds and sesame oil, peanuts, almonds and sunflower seeds
2. Wholegrain bread, oats and brown rice
3. Legumes — dhal, chickpeas, beans
4. Fortified yoghurt drinks and spreads sold with a cholesterol-lowering claim — check the label for plant sterol content
5. Avocado and vegetable oils

How much do I need?

There is no recommended intake for phytosterols, and Singapore's RDA table does not list them. Around 2 g a day from fortified foods is the amount shown in studies to lower LDL; ask your doctor whether it suits you, especially if you take statins.

Low intake and deficiency

There is no deficiency. The body does not need phytosterols.

Too much and safety

Phytosterols are considered safe for most adults at the usual doses. They may slightly lower absorption of fat-soluble carotenoids; eat plenty of fruit and vegetables. Fortified products are not intended for young children and are generally not advised for pregnant or breastfeeding women without advice. People with the rare inherited condition sitosterolaemia must avoid them.

Phytosterols lower cholesterol but have not been shown directly to prevent heart attacks, and they do not replace healthy eating or prescribed medicine.

Absorption and bioavailability

Only about 5 percent or less of plant sterols is absorbed, far less than cholesterol. They work in the gut by competing with cholesterol, and are most effective taken with meals containing some fat.

Connection to daily life

1. Heart health: one of several tools alongside soluble fibre, fish and unsaturated fats
2. Healthy ageing: useful for adults with raised LDL, with medical advice
3. Related: see Cholesterol

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. Health Promotion Board — Singapore Food Insights Database (SG FoodID): https://www.hpb.gov.sg/healthy-living/food-and-beverage/sgfoodid/ 4. FAO/INFOODS — Food composition tables and databases: https://www.fao.org/food-composition/tables-and-databases/en/