The UK has one of the highest average cholesterol concentrations in the world, with two out of three adults having levels above the government recommendation of 5mmol/L.1 Having a raised level of 'bad' LDL-cholesterol is associated with an increased risk of cardiovascular diseases such as heart attack and stroke - especially if you also have a reduced level of 'good' HDL-cholesterol.
Balancing cholesterol levels
Despite its bad reputation, cholesterol is essential for health and is critical for the manufacture of cell membranes, steroid hormones and vitamin D, for example. However, having a raised level of low-density lipoprotein (LDL) cholesterol can contribute to hardening and furring up of the arteries (atherosclerosis) - especially if your intake of antioxidants is low.2 Antioxidants help to prevent the formation of oxidised LDL particles which are associated with inflammation and the accumulation of cholesterol plaques in artery walls. In contrast, having a high HDL (high-density lipoprotein) cholesterol level protect against atherosclerosis by mopping up excess LDL-cholesterol and transporting it back to the liver for processing. So, if you are told your cholesterol level is raised, it's important to know the balance between your LDL-cholesterol and HDL-cholesterol.
Cholesterol and atherosclerosis
Atherosclerosis is the term for hardening and furring up of the arteries. Healthy arteries need to remain elastic to even out the peaks and troughs in blood pressure that occur as your heart pumps blood around the circulation. Once arteries begin to stiffen, your blood pressure will start to increase as blood vessels lose their elasticity. As fatty plaques (atheroma) accumulate, arteries become increasingly narrow, so blood flow is restricted. When this process affects the relatively narrow arteries supplying heart muscle, this can lead to angina (heart pain) or a heart attack. When atherosclerosis affects blood vessels supplying blood to the brain, the risk of a stroke or of memory loss is increased. Maintaining a healthy cholesterol level can help to prevent atherosclerosis or to slow its progress.
If you have a high cholesterol, your GP will most likely recommend that you take a type of medication called a statin. Statins suppress the production of cholesterol in the liver. Dietary changes can also help.
How to reduce cholesterol through nutrition
Several nutritional approaches can help to improve cholesterol balance and slow the progression of atherosclerosis.
Aim to eat at least five servings of fruit and vegetables per day. These supply fibre, which slows the update of cholesterol in the gut, and antioxidants that protect circulating cholesterol from oxidation. Plant-based foods also provide plant sterols which block cholesterol absorption.
Reduce your intake of saturated (animal) fats and instead favour unsaturated fats such as omega-3 (eg found in oily fish and walnuts), omega-6 (eg found in seeds and their oils) and monounsaturated fats (eg found in olive oil and avocado). A Mediterranean style diet is ideal.
Eat wholegrain cereals such as oats and pearl barley - these contain a type of fibre called beta glucan which binds to cholesterol in the gut to reduce its absorption.
What supplements can improve cholesterol balance?
Several supplements have beneficial effects on cholesterol, of which the most effective are plant sterols, globe artichoke, garlic and krill oil.
Plant sterols and stanols (phytosterols) are found naturally in plants and are structurally like cholesterol. They block cholesterol receptors in the gut to reduce cholesterol absorption without being significantly absorbed themselves and may also stimulate the direct secretion of cholesterol from the circulation into the gut so that more is voided.3 According to the European Atherosclerosis Society (EAS), a daily intake of 2g of plant sterols per day can lower LDL cholesterol levels by 8-10%.4
There are two authorised EU health claims relating to plant sterols:
- 'Plant sterol supplements contribute to the maintenance of normal blood cholesterol levels.'
- 'Plant sterols have been shown to lower blood cholesterol. High cholesterol is a risk factor in the development of coronary heart disease.'
Globe artichoke extracts are highly antioxidant and have a direct effect on the liver to lower 'bad' LDL-cholesterol and promote the production of 'good' HDL-cholesterol. Studies suggest that taking artichoke extract for 6 to 12 weeks can lower total cholesterol levels by between 4.2% and 18.5%. However, more research is needed to confirm these promising findings.5
Garlic contains allicin, a powerful antioxidant that reduces cholesterol production in the liver and hastens excretion of fatty acids to lower blood levels. The results from 14 studies show that garlic supplements significantly lower total cholesterol and 'bad' LDL-cholesterol while raising 'good' HDL-cholesterol when compared with placebo.6 The average cholesterol reduction is around 10% when taken for more than 2 months.7
Krill oil is derived from a shrimp-like crustacean and combines beneficial omega-3 oils (DHA and EPA) with two powerful antioxidants, astaxanthin and canthaxanthin. The results from 7 clinical trials show that taking krill oil supplements can significantly lower LDL-cholesterol and raise beneficial HDL-cholesterol,8 learn more about balancing cholesterol with krill oil here.
For more information on how to keep your heart healthy, see our heart health hub.
1Universty of Birmingham (no date). Cholesterol, Bham.ac.uk
2Zhang PY, Xu X, Li XC (2014). Cardiovascular diseases: oxidative damage and antioxidant protection, Eur Rev Med Pharmacol Sci 18(20):3091-6
3De Smet E, Mensink PR, Plat J (2012). Effects of plant sterols and stanols on intestinal cholesterol metabolism: suggested mechanisms from past to present, Mol Nutr Food Res 56(7):1058-72
4European Atherosclerosis Society (no date). Consensus on plant sterols, EAS Society
5Wider B et al. (2013). Artichoke leaf extract for treating hypercholesterolaemia, Cochrane Database Syst Rev (3):CD003335
6Sun YE, Wang W, Qin J. (2018). Anti-hyperlipidemia of garlic by reducing the level of total cholesterol and low-density lipoprotein: A meta-analysis, Medicine (Baltimore) 97(18):e0255
7Reid K. (2016). Garlic Lowers Blood Pressure in Hypertensive Individuals, Regulates Serum Cholesterol, and Stimulates Immunity: An Updated Meta-analysis and Review, J Nutr 146(2):389S-396S
8Ursoniu S et al. (2017). Lipid-modifying effects of krill oil in humans: systematic review and meta-analysis of randomized controlled trials, Nutr Rev 75(5):361-373.