Understanding Drug Nutrient Interactions

Top level summary

• DNIs are defined as alterations of pharmacokinetics or pharmacodynamics of a drug or nutritional element, or a compromise in nutritional status as a result of the addition of a drug
• Examples of where DNIs can occur include statins, contraceptives, proton pump inhibitors, and cases where vitamins and lipids have a synergistic effect with drugs
• Although DNIs have not been extensively studied to date, it is particularly relevant for the elderly, as they are often prescribed several medications at once
• Adverse drug reactions can have serious consequences, with drug side effects responsible for an estimated 197,000 deaths each year in the European Union²
• Increasing understanding of DNIs could have a significant impact on public health

Understanding the potential of DNIs

Improved knowledge of potential interactions between drugs and nutrients could have a significant impact on public health.³

While drug-drug interactions are widely recognized as clinically relevant, DNIs have previously been underexplored, despite the number of studies on their presence and relevance. This is becoming increasingly important as the population ages, and more individuals suffer from multimorbidity, making polypharmacy prevalent.

In the European Union, drug side effects are estimated to be responsible for 197,000 deaths a year, with the risk of adverse drug reactions increasing with advancing years.⁴ Despite the potential consequences, DNIs are not considered during the drug development phase, as there is limited nutritional knowledge among researchers and professionals in the health care field.

Making the distinction

In order to start to classify DNIs, a proposed framework has been developed as part of a recent workshop to help structure the consequences. For example, by distinguishing the effects of meals, individual foods, specific nutrients or nutrition status on drug action, and vice versa, it is easier to determine the impact of drugs on nutrition status:

• Class 1 – effect of obesity and malnutrition on drug action
• Class 2 – effect of nutrition on drug action
• Class 3 – effect of specific nutrients or dietary supplements on drug action
• Class 4 – effect of drugs on nutrition status
• Class 5 – effect of drugs on nutrient status

Taking the pharmacological mechanism and localization of the interaction into account could lead to further sub-classes.

What do we know already?

Several potential associations have already been made between certain drugs and nutrients, which are shaping future research in this area.

For example, lipid-lowering therapy with statins can significantly reduce the incidence of cardiovascular disease and decrease the likelihood of coronary events. However, aggressive lowering of lipids by statins comes with the risk of decreasing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels simultaneously. EPA and DHA can be considered as an alternative way to help reduce plasma triglyceride levels and to beneficially influence the levels of other blood lipids as well. Clinical trials have shown that EPA and DHA as supplementation may also be effective in combination with lipid-lowering drugs like statins.⁵

In addition, nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen and naproxen, can cause peptic ulcers, diminish renal function and impair vitamin B6 metabolism. However, they may have additive or synergistic effects with certain vitamins or lipids, for example to reduce pain.⁶ If an adequate dose of EPA and DHA (which have anti-inflammatory properties) is provided, NSAIDs might be taken at a lower dose to have a clinical benefit and reduce potential side effects of the drug.⁷

Building a bank of evidence

The growing number of studies on DNIs suggests that exploring the impact of drugs on nutrient status could prove beneficial in the future. Particularly given the nutritional status of many elderly people, it would be worthwhile conducting a systematic assessment of nutrient-drug interactions, starting with classes of drugs used in common complex disorders. While current medicine is pharma-dominated, further research could pave the way for nutrition playing a bigger role in public health.

For more information on potential drug-nutrient interactions, download our whitepaper, 'Vitamins for pharmaceutical applications'.