BlogHow diet interacts with medical cannabis oil

How diet interacts with medical cannabis oil

12 min read

Emily Ledger

How diet interacts with medical cannabis oil

While we may be cautious about drug-drug interactions, many of us likely give little thought to potential food-drug interactions. In this article, and to commemorate this year’s Nutrition and Hydration Week, we’re taking a closer look at how diet can influence the effects of medical cannabis oil. 


Medical cannabis can refer to a huge number of medicinal products derived from the cannabis plant - a plant with thousands of active ingredients, including cannabinoids, terpenes, and many more. As such a complex therapeutic tool, identifying the right dose and the most effective way to consume medical cannabis can be difficult and vary from person to person. 

What is Nutrition and Hydration Week?

Nutrition and Hydration Week has taken place in March every year since 2012. It was introduced as a way to “bring people together to create energy, focus and fun in order to highlight and educate people on the value of food and drink in maintaining health and well-being in health and social care.”

The week-long event invites organisations from health and social care sectors around the world to take part by sharing facts and breaking myths about food, drink, and health. On Wednesday 13th March, Nutrition and Hydration Week will host the Global Tea Party and urge participants, no matter where they are in the world, to take part by holding their own events. 

This year’s Global Tea Party will be supported by Love British Food with a focus on recipes using local produce. There will also be a new competition across three classes to showcase culinary skills, creativity and innovation!

Nutrition and Hydration Week is open to anybody who wants to get involved and spread understanding of this important message. For more information or to find out how your organisation can take part, visit the Nutrition and Hydration Week website.

The importance of nutrition in a treatment setting

It may seem obvious that a good diet is a crucial component of overall physical health. But what many people may not realise is that good nutrition is also vital for maintaining proper physiological and psychological functioning - a fact that prompted the World Health Organisation and the Food and Agriculture Organisation of the UN to launch the ‘United Nations Decade of Action on Nutrition’ (2016-2025). Nutrition can even significantly impact the efficacy of medical interventions, making it a particularly important consideration in a clinical setting. 

Evidence suggests that maintaining good nutrition can have a significant impact on the effective treatment of a wide range of conditions, from diabetes and arthritis to mental health disorders including depression and anxiety. But the link between diet and effective treatment doesn’t end there. 

The food we eat can also impact how our body responds to certain medications. For example, some foods may increase or decrease the absorption of a drug, leading to an alteration in the effects of the medication. Depending on the food and drugs being consumed, this can mean that too little or too much of the drug is absorbed, which in some cases can lead to serious complications. 

Food-drug interactions

If you have ever been required to take multiple medications at the same time, it is likely your doctor will have explained the importance of being aware of drug-drug interactions. This refers to interactions between two or more drugs that may affect how they work or are absorbed by the body. Yet, it can be easy to overlook the significance of food-drug interactions. 

A simple example of this phenomenon is the recommendation to take certain medications on a full or an empty stomach. Depending on the product, instructions for use may recommend taking the medication with or after food; this is because some drugs are absorbed into the body more quickly when the stomach is empty and having food in the stomach will slow down the absorption of the drug. 

On the other hand, some medical products, as well as vitamin supplements, may be recommended to be taken one to two hours before food. This is because some foods and drinks can affect the way these medicines work. For example, grapefruit juice, cranberry juice, and foods high in vitamin K (such as leafy vegetables), can neutralise the effects of certain medicines.

So, what are the rules of thumb when it comes to medical cannabis? Are some foods better than others when taking medical cannabis products? Let’s find out.

Diet and medical cannabis

As we mentioned at the start of this article, cannabis is an extremely complex plant containing thousands of chemical components, including over 140 cannabinoids. Of these, the most well-known and most widely researched are delta-9 tetrahydrocannabinol (known more widely as THC) and cannabidiol (CBD). 

In recent years, medical cannabis products containing primarily these two cannabinoids (sometimes among others) have become more widely available in many countries around the world, including the UK. Patients can now access prescription medical cannabis products such as dried flower, cannabis oils, and oral sprays for the treatment of a wide range of conditions. With various products available, there is some debate around the most effective method of consumption, with different routes offering different pros and cons. However, one factor that is considered to be particularly important is bioavailability.

What is bioavailability?

Bioavailability refers to the proportion of a drug or other substance that is effectively absorbed into the body and reaches systemic circulation - in other words, how much of a consumed drug is able to have an active effect. In contrast, the bioaccessibility of a substance refers to the quantity of a compound that is released from the food matrix and becomes available for absorption by the intestinal epithelial cells. 

The bioavailability of a substance can vary depending on several factors, including the route of administration and the presence of other substances. Being able to accurately estimate how much of a given drug will be effectively absorbed is crucial for ensuring appropriate dosing

Administration routes such as inhalation and intravenous administration (injection into veins) generally offer a much higher bioavailability than oral consumption as they allow the active substances to bypass being broken down in the stomach or liver - this is known as the first-pass effect or first-pass metabolism; however, due to offering more convenience, oral products such as capsules and pills, as well as oils and sprays, are the most common forms of medications outside of a clinical setting. 

The bioavailability of cannabinoids

As with many other medicines, the bioavailability of cannabinoids can vary significantly depending on the route of administration. Some findings indicate that inhaled cannabinoids exhibit similar pharmacokinetics to those administered intravenously with the bioavailability of THC after inhalation believed to range from 10% to 35%. Similarly, inhaled CBD has been found to have an average systemic bioavailability of 31%. In contrast, the bioavailability of cannabinoids taken through other routes can be significantly lower.

What is the oral bioavailability of CBD?

In recent years, CBD has become an increasingly popular ingredient in the medical world, in addition to representing one of the fastest-growing areas of the wellness industry. Many different CBD-based products can now be purchased over the counter in pharmacies, health shops, and even supermarkets. Many of these products, including oils, drinks, and edibles, are designed to be taken orally or sublingually. Furthermore, Epidyolex, a CBD-based oromucosal spray solution was the one of first licensed medical cannabis products to be made available in the UK.

Yet, due to the first-pass effect, oral products offer among the lowest bioavailability of any cannabis-based product with the estimated bioavailability of oral CBD ranging from between 6% to 13%. Sublingual administration of oils (where a solution is held under the tongue to be absorbed through the tissues in the mouth) has been seen to offer bioavailability of between 1 and 19%, and in some cases, as high as 35%. 

Enhancing the effects of medical cannabis

Cannabinoids such as THC, CBD, and many other similar compounds, are lipophilic (or fat-loving) substances. This means that they have an affinity to fats and can bind effectively with fatty tissues. Over extended periods of exposure, cannabinoids have been found to accumulate in the fatty tissues of the body. However, when taken orally, exposure to the digestive system means that a significant proportion of cannabinoids will be destroyed before they are absorbed into the bloodstream.

Yet, various studies have demonstrated how consuming cannabinoid-based products, such as medical cannabis oil, alongside other lipids can significantly increase their bioavailability and bioaccessibility - even when consumed orally. For example, a 2016 animal study found that oral co-administration of fats enhanced systemic exposure of rats to THC and CBD by 2.5-fold and 3-fold, respectively, compared to lipid-free formulations.

Another study, published in 2021 aimed to analyse the bioaccessibility of CBD after a three-phase upper digestion experiment both with and without food. The researchers found that fat supplementation significantly increased the bioaccessibility of CBD leading them to conclude with a recommendation that CBD be consumed “with food high in fat to increase micellarisation of CBD for optimal absorption through the intestinal epithelial cells.”

The best and worst foods to eat alongside medical cannabis 

Research indicates that eating fatty foods alongside your cannabis-based medicines can improve the absorption of cannabinoids. However, this doesn’t necessarily mean that you should be eating a beef burger every time you medicate. 

It is important to remain aware of the health implications of the food you eat as well as their impact on cannabinoid absorption. Thankfully, there are some “healthy” fats that could satisfy both camps.

Getting the most out of your medical cannabis oil or other cannabis-based products could be as simple as opting for food high in “good’ unsaturated fats while avoiding saturated fats and trans fats. Foods containing high levels of omega fatty acids may also be helpful.

Some fatty foods that may be effective at enhancing cannabinoid absorption include:

  • Olive oil; rapeseed oil (unsaurated fat)
  • Corn oil; Sunflower oil (Omega-6 fats)
  • Avocados (unsaturated fat)
  • Almonds; Brazil nuts; peanuts (unsaturated fat)
  • Oily fish: Kippers; sardines; mackerel (Omega-3 fats)

Foods that contain unhealthy fats that should be limited to maintain a healthy diet include:

  • Processed meats: sausages; bacon
  • Butter; ghee; lard
  • Cream and cheese products
  • Milky chocolate
  • Coconut oil and cream
  • Biscuits, cakes and pastries

Should I take cannabis oil before or after a meal?

Whether you should take your medical cannabis oil before or after a meal can depend on a number of factors. For example, the formulation of your medication may require that you medicate on an empty or full stomach. Your prescribing physician will be able to give you tailored advice on the best time to take your medication. But let’s take a look at some other questions relating to medical cannabis and diet.

Can you take cannabis oil while fasting?

While taking medical cannabis oils (and other cannabinoid-based products) alongside fatty foods can help to enhance the absorption of cannabinoids, this doesn’t necessarily mean that strong effects won’t be achieved when consuming them on an empty stomach - such as when fasting for health or religious reasons. 

In fact, consuming cannabinoids on an empty stomach may increase the risk of side effects such as drowsiness, anxiety, and nausea. Furthermore, cannabis consumption can trigger food cravings that can make it more difficult to refrain from eating during periods of fasting. However, this may depend on the exact formulation of your cannabis oil as the majority of these side effects are associated with THC.

Is it safe to take cannabis oil every day?

Medical-grade cannabis oil is subject to strict regulations to ensure the safety of patients. Patients who are prescribed medical cannabis are under the supervision of qualified clinicians who will monitor their reactions to the medication and recommend a tailored dosing routine based on the findings. 

For most patients who are using cannabis oil and other medical cannabis preparations, it is essential to maintain their recommended dosing regime, which may involve multiple doses per day. Current evidence suggests that, when administered under controlled circumstances, using cannabis oil every day is relatively safe and can enhance the efficacy of treatment for a number of health conditions. 

However, we also know that some individuals may build a tolerance to cannabinoids over time. This may make it necessary to increase the dose of cannabinoids to achieve the same results. It is important to stick to the dosing regime recommended by your prescribing doctor.

Final thoughts

Nutrition is an incredibly important consideration when treating any health condition. Maintaining healthy levels of nutrients through diet can help to maintain overall physical, physiological, and mental health. Likewise, diet can play a vital role in the effective absorption of cannabinoids - particularly when cannabis products are used medicinally. 

While fatty foods are known to enhance the bioaccessibility of cannabinoids, including CBD and THC, caution should be exercised when selecting the best sources of fats to prevent over-consumption of “unhealthy fats” such as saturated and trans-fats. Instead, placing a focus on unprocessed foods and healthy fats may be effective at increasing the absorption of cannabinoids in medical cannabis products while maintaining a healthy approach to nutrition that could further benefit your treatment.

If you are considering significantly changing your diet when consuming medical cannabis, it is recommended that you discuss this with your doctor to ensure you do so safely.

It is important to seek medical advice before starting any new treatments. The patient advisors at Releaf are available to provide expert advice and support. Alternatively, click here to book a consultation with one of our specialist doctors.

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Emily, an accomplished content writer with a specialisation in cannabis and alternative health, leverages her five years in the sector to enhance education and diminish stigma around medicinal cannabis use.

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