But so far, Professor Sumnall points out, CBD products in shops are marketed as food supplements, not medicines, so none of them have gone through this process.
Since 2016, any CBD product that is presented as having medicinal value must be licensed and regulated as a medicine, regardless of whether it is actually effective. Manufacturers must follow very specific and robust rules around production, packaging and the information provided.
Professor Sumnall argues that while it could be effective for some people, in some of these cases the results could be caused by the placebo effect (where the patient’s belief in a treatment makes them feel better). The placebo effect can be powerful, but Professor Sumnall warns that if people try CBD oil instead of speaking to their doctor, it could cause a problem.
“It’s clear that CBD has potential,” says Professor Sumnall, “but we’re at a very early stage of that research.”
Does CBD work?
The biggest difference between CBD used in clinical trials and in stores is the dose. Research has shown that some products contain very little CBD (or even none at all). Others contain THC or other illegal drugs, or even alcohol instead of CBD. By contrast, in clinical trials the CBD is purified, manufactured to a very high standard and given at a much higher dose. It is also taken regularly and under medical supervision.
CBD is the latest health craze to sweep the high street, with claims it can help everything from chronic pain and inflammation to anxiety. But what is CBD, and can it really help the heart? Emily Ray finds out.
Many of these can be easily picked up from reputable high street stores, such as Holland & Barrett or Boots.
Can CBD help the heart?
Prices can be high: a 500mg bottle of CBD oil oral drops could set you back as much as £45. Not that this has put people off: over the past two years, sales of CBD have almost doubled in the UK, putting regular users at an estimated quarter of a million.
However, it also notes that this research is still in the early stages, and that more studies are needed before conclusions can be drawn on whether CBD is effective.
The individual blood pressure responses of healthy volunteers to the stresses are presented in Figure 2 , showing the average baseline systolic or diastolic blood pressure in the 4 minutes preceeding the stress test, the peak response during stress, and the average recovery response in the 4 minutes after the stress test.
The cold pressor test caused a rise in SBP (placebo P < 0.01, CBD P < 0.05; Figure 5A ) and MAP (placebo P < 0.001, CBD P < 0.05; Figure 5C ) in both groups and a rise in DBP only with placebo (P < 0.01; Figure 5B ). An equal rise in SBP and MAP was seen with both CBD and placebo in the first half of this stress test. However, while the blood pressure (SBP and MAP) continued to rise in the placebo group, it plateaued in volunteers who had taken CBD, and therefore both SBP and MAP were significantly lower in volunteers after CBD (mean difference –8 mmHg [95% CI, –4 to –12, P < 0.01] and –6 mmHg [95% CI, –2 to –11, P < 0.01]). Post-hoc analysis showed that DBP was also significantly lower in those who had taken CBD in the latter half of the stress period ( Figure 5B ; P < 0.001).
Mental stress test.
Subjects who had taken CBD had increased HR (mean difference 10 bpm; 95% CI, 5–14, P < 0.01, Figure 4D ) and decreased SV (mean difference –13 ml; 95% CI, –4 to –22, P < 0.01, Figure 4E ) and EJT (mean difference –0.01 sec, 95% CI, –0.001 to –0.03, P < 0.05, Figure 4G ) during the exercise stress. There was no difference in CO during the exercise stress ( Figure 4F ).
Effect of CBD on cardiovascular parameters in response to exercise stress.
KAJ helped with study design, researched data, wrote the manuscript, and reviewed/edited the manuscript. GDT reviewed/edited the manuscript. SEO was involved in study design and reviewed/edited the manuscript.