Junk Food vs Real Food?

Many years ago, when I first started lecturing on Food Microbiology at the Department of Food Technology, Massey University, one of the staff members, for whom I have a great respect, Professor Mary Earle, said to me "There is no such thing as junk food, just poor food choices".

Unfortunately, the media love the words "junk food" and use them at every opportunity.  TVNZ One News published an article under the heading

"NZ's 'obesity crisis' won't be solved by dairy sweet ban - health expert".

Quoting from the article:  A new report from Auckland Regional Public Health Service has called for limits on how many convenience stores can set up in one area, and what foods they can sell to children.  The proposals were made in a report to obesity-fighting group Healthy Auckland Together, which plans to lobby for changes to the Resource Management Act to allow councils to govern where dairies, takeaways and other convenience stores can set up.

Speaking to TV ONE's Breakfast this morning, Boyd Swinburn, Professor of Population Nutrition and Global Health, said New Zealand could even consider a trial of a junkfood exclusion zone for dairies within a certain distance to a school, as is the case in Korea.

The liberal use of the term "junk food" in the article is an inappropriate catch-all. Do the authors mean to include hamburgers, pizza or fish and chips along with sweets? It can be argued that a hamburger is highly nutritious - protein (meat and possibly cheese), carbohydrate, salad vegetables. Possibly the sauce contains too much sugar. Another colleague, food technologist Garth Wallace, once said that a serve of fish and chips with some bread and butter and a glass of beer was a balanced meal.


The problem is not the food; it's the consumption pattern. If you eat hamburgers for every meal, you will soon begin to feel unwell, as demonstrated in a recent television documentary broadcast in New Zealand.  In addition, Tim Spector, Professor of Genetic Epidemiology at King's College, London, has published an article in The Conversation, "Your gut bacteria don't like junk food, even if you do". Note once again the words used to describe the diet. The article described an experiment carried out with his son Tom, who changed from an average western diet to an intensive fast food diet for a week. Tom's gut bacteria were analysed over the course of the experiment.  "Tom’s gut had seen massive shifts in his common microbe groups for reasons that are still unclear. Firmicutes were replaced with Bacteroidetes as the dominant type, while friendly bifidobacteria that suppress inflammation halved. However the clearest marker of an unhealthy gut is losing species diversity and after just a few days Tom had lost an estimated 1,400 species – nearly 40% of his total. The changes persisted and even two weeks after the diet his microbes had not recovered".

In my opinion, this is clear evidence that a proper balanced diet is the right way to maintain a healthy body and gut microbiome.  The components of the diet are much less important than the relative proportions and frequency of consumption.

This article represents my own opinions, and is not necessarily the view of NZIFST.

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."

If we look further, in my opinion, 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

1.  Kyndt, T. et al.   

www.pnas.org/cgi/doi/10.1073/pnas.1419685112 

On sugar, sucrose, fructose. Lets get the terminology right!

The latest media blast of anti-sugar material again highlights the inaccuracy or lack of clarity in reporting these sorts of stories. Few interviewers are clear on the sugar/fructose/glucose ie sugar chemistry picture and let the interviewee swap from talking about sugar to fructose and back to sugar again without realising that there is a need for clarity.

High Fructose Corn Syrup 

Can we all, please, tell everyone we know, that New Zealand food manufacturers use sugar ie sucrose to sweeten foods, not, that is NOT High Fructose Corn Syrup. HFCS, the source of much of the fructose in US diets is largely used to sweeten 'sugary drinks’ there, as it is a cheaper option. In this country, HFCS is used as a texture modifier in very small quantities because it is a relatively expensive option.
Let’s get this clear!