Side Effects of Plant Sterols and Stanols
Plant sterols and stanols are generally well-tolerated with mild gastrointestinal side effects being the most common adverse effects, and they have "generally recognized as safe" (GRAS) status in the United States. 1
Common Gastrointestinal Side Effects
The most frequently reported side effects are mild and self-limiting:
- Mild bloating may occur with regular consumption 1
- Diarrhea can develop in some individuals 1
- Constipation is another potential gastrointestinal effect 1
These gastrointestinal symptoms are typically dose-dependent and resolve with continued use or dose adjustment. 1
Nutrient Absorption Concerns
Reduced carotenoid and fat-soluble vitamin absorption represents a potential safety concern that requires dietary compensation:
- Plant sterols may decrease plasma levels of fat-soluble vitamins and antioxidants 2
- Regular consumption of fruits and vegetables helps counteract this potential effect and should be emphasized to patients 1
- The Academy of Nutrition and Dietetics reviewed 28 studies showing no adverse effects with plant sterol/stanol consumption when adequate fruit and vegetable intake is maintained 1
Critical Contraindication
Plant sterols are contraindicated in patients with phytosterolemia (sitosterolemia), a rare genetic disorder of plant sterol metabolism. 1, 2 This represents the only absolute contraindication to their use.
Drug Interactions to Avoid
Bile acid sequestrants (BAS) must be separated from plant sterol consumption by 2-4 hours to prevent binding in the gut and reduced efficacy of both agents. 1, 2
Important Clinical Caveats
- No serious adverse effects have been documented in clinical trials using doses of 1.6-3 g daily for durations of 3-12 weeks 1
- Plant sterols work mechanically in the intestine and are not hepatotoxic, making them safe even in patients with mild liver function test elevations 2
- The cholesterol-lowering effect plateaus at doses above 3 g/day, so higher doses provide no additional benefit and may increase the risk of gastrointestinal side effects 1, 2
- Despite effective LDL-cholesterol lowering, no randomized controlled trials have demonstrated reduction in cardiovascular morbidity or mortality 1, 2
Safety in Special Populations
Plant sterols demonstrate similar efficacy and safety profiles in patients with and without diabetes, with no differential adverse effects observed. 1, 2 Studies in children with familial hypercholesterolemia have also shown acceptable safety profiles. 2