HEARTACHES

HEALTH & SCIENCE The heart of the matter

By Dan Webster

EVERCANNABIS CORRESPONDENT

For most of the past year, COVID-19 reigned as the world’s main health concern. Yet even then, as now, the No. 1 cause of death around the world involved the human heart.

That’s according to the World Health Organization, which says the “world’s biggest killer is ischemic heart disease” – defined as heart problems caused by narrowed heart arteries.

“Since 2000,” the WHO reports, “the largest increase in deaths has been for this disease, rising by more than 2 million to 8.9 million deaths in 2019.”

Here’s the bad news for those who smoke cannabis: Not only can doing so cause an undue strain on your heart, it’s also particularly harmful for those with an established history of heart disease.

A 2017 story in Harvard Health Publishing, a newsletter published by Harvard Medical School, cites research that indicates that cannabinoid effects include “raising resting heart rate, dilating blood vessels and making the heart pump faster.”

This may not mean much to those with otherwise healthy hearts, the story asserts, but “it should be a red flag for anyone with a history of heart disease.”

Research conducted by the American Heart Association agrees with the WHO assessment, especially when it comes both to the methods of delivery (smoking or vaping as opposed to edibles, tinctures, etc.) and to the presence of THC.

“Many consumers and health care professionals don’t realize that cannabis smoke contains components similar to tobacco smoke,” said Robert L. Page II, chair of the group that authored the AHA statement, which was released in August 2020.

Furthermore, the AHA report linked “THC-containing products” with such heart problems as “vascular inflammation and oxidative stress.”

While emphasizing that cannabis may have benefits – among them relief from muscle stiffness associated with multiple sclerosis and neuropathic pain felt by those afflicted by Type 2 diabetes – the AHA report was clear in its evaluation of cannabis and the heart.

“Cannabis,” the report stated, “does not appear to have any well-documented benefits for the prevention or treatment of cardiovascular diseases.”

Yet the same report indicated that use of CBD – cannabis products with little or no THC – can actually be heart-healthy in a number of ways, from reducing heart rate and lowering blood pressure to lessening inflammation and increasing the ability for arteries to open.

More good news regarding CBDs and heart health was announced during the summer of 2019 at a symposium held by the International Cannabinoid Research Society. The news involved a study that examined “the acute and chronic effects of cannabinoid on cardiovascular function.”

Conducted at England’s University of Nottingham, the study indicated that CBDs were capable of lowering blood pressure during stress.

While there were some issues involving tolerance to “chronic CBD administration” that concerned the researchers, spokeswoman Saoirse E. O’Sullivan lauded the “positive effect in vascular function” that the CBDs achieved. Such an effect, she added, “warrants further investigation in relevant patient populations.”

Further investigation, in fact, is the ongoing rallying cry for most cannabis researchers, including the chair of the AHA study mentioned above.

“We urgently need carefully designed, prospective short- and long-term studies regarding cannabis use and cardiovascular safety as it becomes increasingly available and more widely used,” Page said. “The public needs fact-based, valid scientific information about cannabis’ effect on the heart and blood vessels.”

Cardiac studies present mixed results

STUDIES

Continued from 9

aromatic oils that give cannabis varieties distinctive flavors like citrus, berry, mint, or pine) and cannabinoid (chemical compounds found in the cannabis plant in differing quantities) content of each sample.

According to the journal’s description of the study, the lab looked at the principal components that made up each sample in order to define “clusters” in data sets that represented both cannabinoids and terpenoids, cannabinoids only, or terpenoids only. There weren’t as many clusters as many expected:

“The number of predicted clusters was small: two clusters for cannabinoids and terpenoids combined, three clusters for cannabinoids only, and three clusters for terpenoids alone.”

For cannabinoids, 93% of the samples fell into one cluster, or had a very similar makeup. Except for the samples that were high in CBD, all samples contained high amounts of THC, an average of 22%, and very small amounts of other cannabinoids.

For terpenes, there were three distinct clusters, representing 59% myrcene (the most common terpene in cannabis that is responsible for the peppery, spicy, and balsam smell), 33% terpenine (a group of isomeric hydrocarbons that derives naturally from cannabis and other plant sources, including cardamom, marjoram, and oils of juniper and eucalyptus), and 8% limonene, the major component in the oil of citrus fruit peels.

How did this happen, when we have been led to believe we have so many options when it comes to legal marijuana?

“The vast majority of commercially-cultivated Cannabis plants are produced through cloning,” wrote study researchers. “Clonal propagation ensures that plants are genetically identical to the mother plant. In contrast to varieties propagated through seeds, requiring a lengthy process of backcrossing and inbreeding to achieve consistency, new chemovars can be created much faster by clonal propagation. New chemovars are constantly generated and enter the market, resulting in thousands of different breeder-reported names without any scientific naming convention.”

The lack of standardized, uniform cultivation practices leaves it up to growers to classify their product, then name it accordingly. Which isn’t an issue, until you consider that this can be confusing for medical patients who depend on identifications as well as potency data on the packaging.

“The potential for mislabeling of chemovars, inconsistent chemical profiles of marijuana products, and often limited testing data make it difficult or impossible for many patients to obtain a consistent chemical profile of the product,” states the report.

A separate study, documented in the Journal of Cannabis Research in June 2019, also showed that names don’t appear to mean much when it comes to marijuana. But the conclusion of this study is a little different: strains with the same names, purchased at different locations, are often not actually the same strain at all. This study took samples of 30 legal prominent cannabis strains from 20 dispensaries in Washington, Colorado and California.

A genotyping technique of sequencing, commonly used in plant genetic studies, was used to identify genetic groups. It came up with two distinct groups, and surprisingly, they did not correspond to sativa, indica or both.

For instance, two strains commonly known to be sativa-dominant, Durban Poison and Sour Diesel, would have been expected to belong to the same or close genotypes. But study results indicated they had contradicting genetic assignments.

Similarly, three other “similar” strains tested – Purple Haze, Pineapple Express and Tangerine – were thought to be 60/40 hybrids of sativa and indica. But they all were found to have differing makeups.

This study found that almost every same-name strain tested had at least one or more genetic outliers that were mismatched and did not have a similar or same genotype.

“Only four strains out of 30 had consistent genotype assignment and admixture,” wrote report authors Anna Schwabe and Mitchell McGlaughlin. “If you removed the 1-2 outliers, then 11-15 strains showed some consistency, genetic stability and relatedness.”

Study researchers do note that environmental factors like light and cloning over several years can put enough stress on cannabis plants to create differences across a single strain. But overall, they say that after removing outliers, only about half the strains had at least some genetic stability and relatedness.

So what does this mean for you when you go to your neighborhood cannabis retailer? It’s unclear, but in the future you may have fewer decisions to make when shopping.