FOOD & DRINK
PLANT STEROLS AND STANOLS: AN OVERVIEW Junee Sangani Senior Specialist Diabetes Dietitian Junee is currently a Specialist Diabetes Dietitian at Central Middlesex Hospital, London North West Healthcare NHS Trust. She also works as a Freelance Dietitian. Her specialist areas of interest are chronic diseases, adolescent care and women's health.
From as far back as the 1950s, it has been known that increasing dietary intake of plant sterols and stanols can lower serum total and LDL cholesterol.1 Plant sterols and stanols provide an important role in building plant membranes. They naturally occur in all foods of plant origin such as fruits, vegetables, grain products, seeds and nuts and are especially high in vegetable oils. The dietary intake of naturally occurring plant sterols and stanols is thought to be approximately 200400mg/d and in vegetarian diets it can be double the amount.2 Functional food products enriched with plant sterols and stanols have been marketed since 1995, with margarines being the pioneers. Today, there is a large variety of products including drinks, yoghurts and supplements.1,3 PLANT STEROL AND STANOL FUNCTION
Sterols and stanols have a similar function in plants as cholesterol has in humans; they chemically resemble the structure of cholesterol. There are very slight differences in the structure of sterols, stanols and cholesterol which make them profoundly different in metabolic function. They work by competing with and inhibiting cholesterol absorption in the small intestine, leading to excretion of cholesterol. It is also thought that they regulate hepatic expression of LDL receptors and decrease production of LDL cholesterol. Commonly found plant sterol and stanols are campesterol, campestanol, sitosterol and sitostanol.1,4,5 Plant sterols and stanols have the same mechanism for cholesterol lowering as Ezetimibe, a drug that lowers plasma cholesterol levels, so taking them together doesn’t provide any additional benefit and they both appear to reduce cholesterol levels equally.1
Statins work in a different way by inhibiting HMG-CoA reductase, which is an enzyme that plays an important role in cholesterol production, leading to reduced cholesterol synthesis. The cholesterol lowering effect of statins has been proven to reduce the incidence of heart attack and stroke; however, no such effect has been documented with plant sterol and stanol enriched foods and supplements.1,3 However, combining plant sterols and stanols with 2g/d of statins has been shown in clinical trials to reduce LDL cholesterol by 7-10% above the reduction effect of the statin. It is thought that a similar or better than effect is achieved by doubling the statin dose.6,7 RECOMMENDATIONS
It has been well documented that an intake of 2g per day of plant sterol and stanols can lower LDL cholesterol by 8-10%.1 Certain products claim that an intake of 1.5-2.4g per day can lower cholesterol by 7-10% and an intake of 2.5-3g per day can lower by 10-12.5% in two to three weeks.8 It is recommended that these products are eaten with meals to be effective and, if intake of the product is stopped, the cholesterol lowering effect will also stop.5 Overleaf is a guideline to show what is needed to be consumed to get 1.5-3g plant sterol and stanol per day and a table of some of the products available. www.NHDmag.com July 2017 - Issue 126
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FOOD & DRINK
Plant sterols and stanols provide an important role in building plant membranes. They naturally occur in all foods of plant origin such as fruits, vegetables, grain products, seeds and nuts . . .
Either: a) one plant sterol or stanol fortified mini yoghurt drink per day, or b) two to three portions of any of the foods below, providing at least 0.8g of plant sterol per day: • two teaspoons fortified spread (10g) • one fortified yoghurt • a glass (250ml) milk There is considerable variation between an individual’s response to stanols and sterols and this tends to be dose-related. An individual’s LDL response can also vary depending on their baseline LDL cholesterol levels and possibly the type of product chosen and the frequency of intake. Plant sterols and stanols taken in the form of a tablet appear to have a similar effect as that taken in other dietary forms.9 Plant sterols and stanols may be more effective when taken as multiple doses, and the type of plant sterol or stanol enriched food product may affect the results. Further research is needed.10,11 It is not clear what the optimum intake of plant sterols and stanols is and there are limited studies to show the effects of high dose 30
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plant sterols and stanols in humans. However, it appears that eating more than 3g per day of plant sterols and stanols seems to have very little additional effect on cholesterol lowering and may have the adverse effect of reducing the absorption fat soluble vitamins and carotenoids. Reduction may be undesirable and lower concentrations have been associated with an increased risk of several chronic diseases, such as cardiovascular disease (CVD), cancer and age-related macular degeneration (AMD), although evidence from randomised controlled trials is lacking.12 Plant sterols and stanols are not recommended for pregnant or lactating women, or for children aged under the age of five. In pregnant women, they have been shown to reduce the level of carotenoids, including vitamin A which is closely associated with foetal development. In addition, generally, cholesterol is required in the developing brain.13 Plant sterols and stanols have been shown to reduce LDL and total cholesterol. High cholesterol levels have been shown to increase the risk of coronary heart disease and stroke. However, there is limited data and no randomised controlled trials which examine the effect of plant sterols and stanols on cardiovascular outcomes.
Table 1: Examples of products available in the UK Plant sterol/ stanol product
Cost
From £.7.80-£10
Dose Vitabiotics Ultra Plant Sterols 30 tablets per box 1500mg (3 tablets/d) Recommended dose 2-3 tablets (1000-1500mg/ 1-1.5g/d)
£3.60
Flora ProActiv Light Cholesterol Lowering Spread 500g per tub Recommended dose and 3 x servings/d Each serving is 10g
£3.65
Benecol Light Spread 500g per tub Recommended dose and 3 x servings/d Each serving is 10g containing 0.8g plant sterol
£1.50
Asda Cholesterol Lowering Spread 500g per tub Recommended dose and 3 x servings/d Each serving is 10g containing 0.75g plant sterol
£2.55
Benecol Fat Free Berries Yoghurts x 4 pots 125g per pot Each pot contains 0.8g Recommended dose and 3 x servings/d
£3.25
Benecol Yoghurt Drink Blueberry x 6 bottles 65.5g per bottle 2g plant stanol per bottle Recommended dose 1x per day
£2.25
£1.40
Tesco Cholesterol Reducing Blueberry Yoghurt Drink x 6 bottles 100g per bottle 2g plant stanol per bottle Recommended dose 1x per day
Flora ProActiv skimmed milk 1 litre carton Each 250ml serving contains 0.75g Recommended dose 3 x per day
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FOOD & DRINK For this reason, the recent NICE guideline update states that patients should not routinely be advised to take plant sterols and stanols until there is sufficient evidence to show this.14 FUTURE RESEARCH AREAS
There may be a place for plant sterols and stanols to treat hypercholesterolemic children who are still not candidates for statin therapy, or who receive only low-dose statins, and also for people who don’t tolerate statins very well. However, there is not enough information on the efficacy of plant sterols and stanols to be used as a sole therapy in this way.3 In animal studies, plant sterols and stanols have been shown to improve fatty liver through the mechanism of intestinal cholesterol absorption, further trials are needed in humans, but, it is thought that they could play a role in reducing liver fat and inflammation in nonalcoholic fatty liver disease.16 There is some concern that elevated serum plant sterols and stanols may be atherogenic. Phytosterolemia (Sitosterolemia) is a rare disease with elevated serum plant sterol and stanol concentrations due to genetic mutation which can be 50-200 fold compared to the normal
population. These patients commonly have hypercholesterolemia. However, as this disease is so rare, currently little is understood and there is a lack of knowledge about the mechanisms of this condition; a small study showed that of five subjects with Phytosterolemia, despite having elevated plant sterol and stanol levels, none had clinical symptoms of CVD or markers of atherosclerosis.1 CONCLUSION
Overall, plant sterols and stanols have gone through rigorous testing and there is a large body of evidence to back their safe long-term use. It is not essential to take plant stanols or sterols to help manage blood cholesterol levels. Some individuals may choose to take sterols and stanols to reduce their cholesterol levels especially if they have familial hypercholesterolemia or are following the portfolio diet which is a recognised approach to lowering cholesterol16 We must keep in mind that although sterols and stanols have been shown to successfully decrease LDL and total cholesterol, there is limited research about the cardiovascular outcomes and further research is required in this area.
References 1 Helena Gylling and Piia Simonen (2016). Are plant sterols and plant stanols a viable future treatment for dyslipidemia? Expert Review of Cardiovascular Therapy, 14(5): 549-551 2 Ras RT, Geleijnse JM, Trautwein EA (2014). LDL-Cholesterol- lowering effect of plant sterols and stanols across different dose ranges: a meta-analysis of randomised controlled studies. British Journal of Nutrition: 112, 214-219 3 CofĂĄn M and Ros E (2015). Clinical Application of Plant Sterol and Stanol Products. Journal of AOAC International: 98, 3 701-706 4 Han S, Jiao J, Xu J, Zimmermann D, Actis-Goretta L, Guan L, Zha Y, Qin L (2016). Effects of Plant Stanol or Sterol enriched diets on Lipid Profiles in patients treated with statins: Systematic Review and Meta-analysis. www.nature.com/ scientific reports 6, 31337 1-9 5 BDA food fact sheet (2015). Stanols and Sterols. www.bda.uk.comfood facts last cited 20/05/2017 6 Eussen SR, Rompelberg CJ, Klungel OH and van Eijkeren JC (2011). Modelling approach to simulate reductions in LDL cholesterol levels after combined intake of statins and phytosterols/-stanols in humans. Lipids. Health. Dis 10, 187 7 Gylling HPJ, Turley S et al (2014). Plant sterols and plant stanols in the management of dislipidaemia and prevention of cardiovascular disease Atherosclerosis. 232:346-60 8 Commission Regulation (EU) (2014) No 686/2014 of 20 June 2014 amending Regulations (EC) No 983/2009 and (EU) No 384/2010 as regards the conditions of use of certain health claims related to the lowering effect of plant sterols and plant stanols on blood LDL-cholesterol. Journal of the European Union [online] Available at http://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1424856119984&uri=CELEX:32014R0686 [Accessed 20 May 2017] 9 Amir Shaghaghi M, Abumweis SS, Jones PJ (2013). Cholesterol-lowering efficacy of plant sterols/stanols provided in capsule and tablet formats: results of a systematic review and meta-analysis. J Acad Nutr Diet. Nov; 113(11): 1494-503 10 AbuMweis SS, Vanstone CA, Lichtenstein AH et al; Plant sterol consumption frequency affects plasma lipid levels and cholesterol. Eur J Clin Nutr. 2009 Jun 63(6): 747-55. Epub 2008 Jun 4 11 AbuMweis SS, Barake R, Jones PJH (2008). Plant sterols/stanols as cholesterol lowering agents: A meta-analysis of randomised controlled trials. Food and Nutrition Research DOI IO.3402/fnr. v52iO.1811 12 Baumgartmer S, Ras TR, Trautwein EA, Mensinki RP, Plat J (2017). Plasma fat soluble vitamin and carotenoid concentrations after plant sterol and plant stanol consumption: a meta analysis of randomised controlled trials, Eur J Nutr 56, 909-923 13 Laitinen K, Isolauri E, Kaipiainen L, Gylling H, Miettinen TA (2009). Plant stanol ester spreads as components of a balanced diet for pregnant and breastfeeding women: evaluation of clinical safety. Br J Nutr, 101(12): 1797-804 14 NICE (2014) updated 2016. Cardiovascular disease: risk assessment and reduction, including lipid modification 15 Plat J Hendrikx T, Bieghs V et al. (2014) Protective role of plant sterol and stanol esters in liver inflammation: insights from mice and humans. Plos ONE. 9, 10 16 https://heartuk.org.uk/cholesterol-and-diet/six-super-foods-for-lower-cholesterol/portfolio-diet (last cited on 23/05/2017)
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