Food supplement vitamins, minerals, amino-acids, fatty acids, phenolic and alkaloid-based substances: An overview of their interaction with drugs

Food supplements are a widespread group of products ingested as a diet complement, whose consumption has recently skyrocketed due to the consumers' concern with their well-being. Among food supplements, vitamin- and mineral-based ones are the top sellers, and the demand of others, such as those containing polyphenols, is increasing. Owing to their alleged natural characteristics, consumers take the safety of food supplements for granted, and use them even when taking medicines. Thus, their potential interactions with drugs have been sparsely evaluated. This manuscript aims to bring forth an up-to-date overview of the most important knowledge involving the interactions between food supplements and drugs, relevant to be aware by nutritionists and other healthcare professionals. To this end, an extensive bibliographic review was conducted focusing on peer reviewed data from experimental in vivo evidence and clinical studies whenever major clinical interactions have been reported. Elder people and polymedicated or chronic patients are especially vulnerable to the therapeutic ineffectiveness and toxicity caused by these types of interactions. Drugs used to treat cardiovascular, autoimmune, nervous, and oncological diseases are commonly involved in important clinical interactions with food supplements, many with a narrow therapeutic margin.