Garlic, You and Science

Ever wondered how to stop cancer? Diabetes? Yes? The look no further, because the media is taking the curative gasses released from garlic reduce the risk of diabetes, heart disease and cancer. Because all ailments must cure cancer as per the law of media. This claim was seen in both the Daily Mail and The Independent

The study 

The study is a review article entitled Garlic and Gaseous Mediators and comes out of researchers from Nottingham University, which looks at the chemical compounds in garlic and their interactions with cell signalling. The study showed that garlic releases hydrogen sulphide and nitrous oxide into the bodies tissues and investigated whether the compounds that made this happen had any effect on the overall health. This review looks at laboratory studies, rather than looking at in-vivo human studies. This means the results concluded are only speculative, at best. If you have access to the review and have read it, you will notice that this is more of a narrative review. That means it is focusing on literature on a popular topic, but not generating new figures through a systematic review or meta-analysis. These types of reviews are good for us to be able to gain an overall understanding of the topic, but not a good thing to draw such a large conclusion from.

The study draws links between garlic and onions with improved health outcomes i.e: how onions reduce cancers of the digestive tract. The paper linked to this is vastly overstated and placing the reduction/increase in health solely down to one thing is very hard to do. The sole aim of this paper was to discuss whether the compounds in garlic affect cell signalling in the human body. This includes discussing the potential increases to health this may have; such as reducing inflammation. On the contrary to the articles published in the news, the study did not claim that eating more garlic will give you improved health benefits, nor did they claim that supplements are effective either. Dr Rose, who wrote the paper, however says:

“Variety is the spice of life, but understanding the chemistry of some of your spices is probably a very advantageous thing to do.”

Not as advantageous as marketing your research to make it out to be something it’s not though, eh?

Is garlic helpful at all?

It’s a very good flavouring, that’s about it for now. There is no evidence that garlic has any improvement on health. In 2016, a meta-analysis showed there was no effect on cardiovascular health. Again, in the same year a meta-analysis found a slight possible association between those who ate garlic and decreased cancer rate of the upper digestive tract. However, other meta-analyses have found that it isn’t helpful in other cancers. Individual studies making up most of these analyses are case studies, in which conclusions are drawn from people who have tried to remember how much garlic they have eaten in the past.  Do you recall how much garlic you have ingested over the last day? Okay, that’s an easy one. How about the last week? Month? Year? You can’t, surely. Do you know how much is put in your restaurant or take-out food? No. Unless you keep track of absolutely every little thing (which isn’t specifically stated in the studies I’ve read), there is no conclusive evidence for any benefits from garlic consumption.

I have been following food cancer stories for many years. It’s the stories like this that do turn people into sceptics. They are claiming to be able to reduce the risk of diabetes, cancer and heart disease; three massive burdens on the NHS and diseases that take many lives each year. If they were onto cure using an everyday item that is cheap to produce and easy to administer, don’t you think that would be widespread knowledge? I knew people who took garlic capsules to cure their colds, despite a Cochrane review finding zero evidence. It’s myth, but people will literally ignore overwhelming evidence if it is against their beliefs.

Conclusion

Sadly, as with most stories like this, where people don’t science correctly, there is a risk. Garlic has proven interactions with many medications including anti-coagulants, hypoglycemic drugs and quinolone anti-biotics. Thus, supplements should not be taken by people on these medications. A fact of which, all the articles fail to mention. So if you are the type of person who reads things and then just beleieves them because they contain the words 'science' and 'proven' then:

A) Congratulations for making it this far
B) Don't just eat garlic or take supplements
C) If you ignore B, check your medications and consult a doctor (who will most likely tell you the same information as is in the blog post).

There is potential for garlic to affect our health, so far however, it is only the adverse effects which have evidence. A more up-to-date meta-analysis of the evidence would shed light from the individual studies and reveal more information. For now, however, there is no evidence that garlic has any health benefits.