Sunday, April 13, 2014

Take it all with a grain of salt

It's feeling like a lazy Sunday, but I know I have work to do.

I'm trying to advance to candidacy soon, so I apologize if the future posts sound a bit scattered. "Advancing to candidacy" means different things for different graduate programs, but usually entails a qualifying exam to see if a project is worthy of getting a PhD. For my department, five professors sit around a round table, listen to my summation of four years of work, critique the inner workings my project, and then deem whether I am worthy of becoming a PhD candidate.

Astrocytes - one of my research interests
That said, I'm trying to brush up on my reading and am heavy in hermit crab mode. Reading scientific papers critically is an art that you hone over time. For me, I don't know if I'll ever fully grasp this skill. You need to consider how good controls are, how sound the experiments are, and if you believe the central theme of each finding. Sometimes you'll come across really great papers that provide findings that really speak to you; other times, you're left feeling more questionable rather than satisfied.

I dealt with this dilemma a little when I came across this paper through a news report that I found through a friend's Facebook - the headline was "Vegetarians are less healthy and have a lower quality of life than meat eaters." The title itself was very provocative - considering the many sources (anecdotal or scientific) regarding how plant based diets tend to yield healthier results, I was very curious about what the scientific source was.


The article, published in PLOS ONE, reported that vegetarians are at higher risk of being unhealthy, more prone to certain diseases, higher need for health care, and poorer quality of life. In addition to their findings, they also reported vegetarians as having lower BMI and less frequent alcohol consumption.

HOLD THE PHONE. Vegetarians have lower BMIs (a crude measurement of physical healthy that can be used to make cut offs between healthy and unhealthy weight range), but are more prone to diseases? Normally both low BMI and alcohol intake has been indicators for better health, not worse. Strange as it sounds, I looked further into this paper and found that some things were worth noting before taking into consideration the findings:

1. Of the "vegetarian" group, only 0.2% were vegetarians that ate ONLY fruits and vegetables. They had to pool together vegetarians, vegetarians that ate eggs and milk, and vegetarians that eat fish.

2. Vegetarians are considered less healthy because more of them were reported as having allergies, cancer and mental illness. While the numbers may be different between the vegetarians and meat diet groups, you cannot link this directly to diet. Correlation does not imply causation and another factor may be confounding your findings. What does this exactly mean? Think about survey findings of a large city like New York  as having more firefighters and more fires than any other city. Does that mean that the firefighters caused the increase in fires? Not necessarily - because the city is large, has many buildings, there is a higher probability for fires happening, hence a larger need for hiring more firefighters.

3. Vegetarians "required" more health care because this group had people who were vaccinated less and visited the doctor less often than other diet groups. Again, not necessarily linked, and not the best choice for looking at health care.

Overall, there are definite merits to doing large scale epidemiology studies like this mentioned study - you just need to take everything with a grain of salt and look critically at the actual findings. Needless to say, whenever you see an eye-popping article proclaiming to find the newest cure for disease, or a solution for curing memory loss, be sure to keep an open mind!

With that, hope everyone's weekend winds down well.

Happy eating all!

PS. A recent study actually concluded that the best diet for someone is a diet favored heavily towards vegetables and fruits, with lean meats included. Not a big surprise, but good to know!




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