Friday, April 24, 2015

Would you eat transgenic food?

Many readers will immediately respond to the title of this post with a resounding "NO".

Don't be so hasty!

Looking close to home, we find that our own bodies contain many foreign genes.  It is estimated that around 8% of the human genome consists of fragments of endogenous retroviruses - about 100,000 of them.  Not all of these fragments are "junk" (a term the popular press is rather keen on).  A number of viral genes have been co-opted for our own purposes, in gene regulation, production of transfer RNA and ribosomal RNA.  One viral gene is critical to the formation of the placenta.  

On this basis, I'm not too surprised to read a piece of recent research* that shows that some of our vegetable crops are naturally transgenic.  Cultivated sweet potatoes contain the transfer DNA sequences from a bacterium called Agrobacterium.  This genus naturally infects the roots of certain plants, causing a nodule or hairy roots.  This T-DNA is not present in the wild type sweet potatoes, implying that one or more traits carried on this piece of DNA were selected for during the domestication of the sweet potato.The authors of the paper point out that sweet potatoes have been consumed for millennia, and that this "may change the paradigm governing the "unnatural" status of transgenic crops". 

In my opinion, if we look further, it is almost certain that we will find other bacterial or viral genes in our fruits and vegetables.

* The article is technical, but you can find it online

The genome of cultivated sweet potato contains Agrobacterium T-DNAs with expressed genes: An example of a naturally transgenic food crop 

Thursday, April 23, 2015

Dangers of the Google degree

With the explosion of information on the Internet, we all use Google or Yahoo, or perhaps other search engines, to find just about anything, from a second hand multi rotor to nutritional information. I only have to look at the behaviour of my own family to see how important the search engine has become.  I freely admit that when I write a blog or a scientific article, I consult various websites to collect information or links to other websites.

My favourite website is Web of Science; this gives me access to abstracts of scientific papers on just about any subject.  Of course, if you search for a topic such as "Antioxidants", you will get a huge number of hits.  Indeed, I just searched "Antioxidant" and got 35,600,000 hits in 0.27 seconds.  Wikipedia was the lead reference, but many others were from government, university and medical sites.  Others were from commercial sites promoting health foods and bodybuilding aids, and from less easily identified sites, including blogs.

There is a temptation to believe that all sites are of equal standing.  Unfortunately, this is not the case.  With the exception of government-sponsored blogs and websites, almost all blogs, including this one, are published without peer review.  For example, if I read about food borne disease on the Centres for Disease Control website, I can be reasonably confident that the information is correct.

This is not the case for all blogs and websites.  Some authors write authoritatively on the subject, but if you go deeper, you find that the authors have no qualification other than that they "have done the research".

Most times, this is not a big deal; if someone wants to push a point of view, then that's fine.  However, in the case of health and nutrition information, there is the potential to cause great harm.  One could almost label some of the writings as "misinformation".

An area that has been exercising the minds of New Zealand food technologists recently is the exaggerated and misleading claims for coconut oil.  There are regulations in place in New Zealand about making unsubstantiated claims for food products.

The Food Babe has also been hitting the headlines recently.  Her website is a mixture of fact and fantasy.  She writes well, looks happy and healthy, and is convincing in her enthusiasm for the subject.  However, her writings are shot through with errors too many to mention.  The problem is that those with appropriate scientific qualifications can recognise the errors, but the general public does not.  She plays upon the fears of the "worried well".  I'm not going to criticise Food Babe further here.  If you are interested in a more detailed analysis, visit and search for "From the mouth of Food Babe".  See also "What to take away from the Food Babe's meltdown" on

Oh, I nearly forgot.  Food Babe does have a qualification - it's in the field of computer science.