Statins such as simvastatin may have a slight protective effect against Alzheimer's disease. It is generally not recommended to consume grapefruit while taking simvastatin, but other statins like rosuvastatin and pravastatin are compatible with grapefruit consumption. When taking a low dose of simvastatin like 10mg and a small amount of grapefruit, the interaction may not be significant. However, higher doses of simvastatin, such as 40 or 80mg, could potentially have a more pronounced (or dangerous) effect when combined with grapefruit.