Dr Charbin’s Science & Medical Blog ? Hot and current topics in the world of science

Dr Adrian Charbin – the man himself

Here we will discuss hot and current topics in the world of science, where important new discoveries and research flashpoints will be shared and discussed. Oxbridge interviewers often ask about current scientific affairs, so it is very important to be aware of new developments and have informed opinions on them! This blog is written by Dr Adrian Charbin, who studied Natural Sciences at Sidney Sussex, Cambridge. Having specialised in genetics in his final year, Adrian went on to complete a PhD in Biochemistry and Molecular Biology while working for Cancer Research UK and University College London.

Health & Cardiovascular Disease

In the run up to interviews, it is crucial to keep abreast of current affairs as any new stories or recently announced discoveries are a common starting point for discussion.

Recently, a huge study of half a million men and women was published in Biomed Central’s open access journal BMC Medicine, which demonstrates an association between processed meat and cardiovascular disease and cancer. One of the difficulties in measuring the direct effect of eating meat on health is the confounding effect of lifestyle on health. Often vegetarians have healthier lifestyles than the general population, they are less likely to smoke, are less fat, and are more likely to be physically active. Only within a very large study can the consequences of eating meat and processed meat be isolated from other lifestyle choices. You should be ready in an interview to discuss how you might design an experiment to include all the appropriate controls to account for all other factors. A good way to prepare for this is to read through some of the methodology used in actual large scale studies on human populations, so do look at the link above (it is an open access journal, so you do not need to pay to read the full article).

The study, termed EPIC (European Prospective Investigation into Cancer and Nutrition), involved ten countries and 23 centres in Europe and almost half a million people. In general, it was found that a diet high in processed meat was linked to other unhealthy choices. Men and women who ate the most processed meat ate the fewest fruit and vegetables and were more likely to smoke. Men who ate a lot of meat also tended to have high alcohol consumption. However, in addition to this, it was observed that a person’s risk of premature death increased with the amount of processed meat eaten. This is also true after correcting for confounding variables, although residual confounding cannot be excluded. However, a small amount of red meat appeared to be beneficial which the researchers suggest is because meat is an important source of nutrients and vitamins.

So what about processed meat can actually cause illness? There are several mechanisms by which meat may be associated with death, the authors note. Cancer-causing compounds are formed during high-temperature cooking of meat. Meat also is a major source of saturated fat, which has been associated with breast and colorectal cancer. In addition, lower meat intake has been linked to a reduction in risk factors for heart disease, including lower blood pressure and cholesterol levels. Forgotten which cholesterol is ‘good’ and which is ‘bad’? Do remind yourself by clicking here. As such, the authors conclude with the recommendation that no more than 20 grams of processed meat be consumed per day.

Evolution

“Please describe to me an example of evolution in action”. This is a classic interview question that is designed to probe the depth and fullness of your understanding of evolution and its mechanism of action. The best responses will be those that start with a short but accurate description of evolution. This is a crucial step because although all of you will have studied evolution, many students do not have a sufficiently good definition on hand to share. If you remember anything from this blog, please remember NOT to say this: “Evolution is the change in a species over time”. This is not a sufficiently accurate response for Oxbridge, and could at worst hint at Lamarckism! Rather, remember that the fundamental unit of Evolution are genes, so centre all your responses on genetics. A much better answer would be “Evolution is the change in a gene’s frequency over time”. This is a sophisticated answer that few students will come up with and stresses your understanding of the importance of genes in the process of evolution.

Smaller fish tend to be less fertile and produce fewer eggs, depriving a fish stock’s capability to recover from fishing pressure.

Now as for an example, there is a plethora of examples you could use! Many students will have learnt about the peppered moth and the industrial revolution at school and this is a sound example to use. However, your interviewer will always be impressed to hear about novel examples you may know of.  For those applying for medicine, the rise of antibiotic-resistant diseases such as MRSA is very important to know about and is a topic being increasingly covered in the media. For the natural scientists, an interesting example could be how the average size of edible fish such as cod and haddock is decreasing.

While all these above examples are sound demonstrations of evolution in action, can you spot what problem they all share in common? In fact all three examples are examples of evolution resulting from human activity, be that pollution from the industrial revolution, the invention of antibiotics or the pressure we exert on fish stocks from commercial fishing. An ardent creationist could argue that all these examples of ‘evolution’ are in fact not proper proof of evolution as they all involve human involvement. Can you think of any examples of evolution in action that do not involve humans? In my next blog I will discuss some really interesting examples, but in the meantime feel free to do some of your own research into the topic!