Sunday, April 15, 2012

Smart parents raise smart kids-right?

Smart parents raise smart kids, but not for the reasons we all might think.  Making them do their homework, impressing on them the importance of reading, studying, paying attention in class, and generally being committed students, all give our kids the best chance at being smart-right?  Well, it turns out yes, and no.  While all the tricks we parents think we must teach our kids help them make the most of what they've got, what they end up having appears to be as much to do with what we gave them at conception, than whatever we've done for them since.
A large group of scientists running a project with the intriguingly mysterious name, Project ENIGMA, have discover that intelligence is probably affected by our genes to a greater degree than previously thought.  The researchers, from all across the globe pooled their resources and their data to look for correlations between DNA and specific brain disorders (the usual- dementia, depression, Parkinson's, schizophrenia, etc).  While they came up with some interesting data on the diseased brain, what they inadvertently uncovered was a connection between DNA and brain size, and even more curiously, between DNA and intelligence as measured by standardize IQ tests.  IQ tests look for a certain type of intelligence so the data has to be viewed with that in mind, but it appeared that a variant in a gene called HMGA2 may be able to explain differences in individual intelligence.  The difference in the HMGA2 was in one DNA letter only; at one point in the gene, the base thymine (usually represented as T), was replaced by a cytosine base (C).   People that had the letter C instead of T at a certain location on the gene were more likely to have a larger brain and score higher on the IQ tests.
This finding isn't really an answer to the question of inherited intelligence, but rather the starting point for many questions.  Correlation is not the same as causation and the size of the brain, the high IQ score and the genetic change, may all be linked by something else in the brain not yet found.  However, the association is interested and the methodology used by Project ENIGMA even more interesting.  Because it is difficult to obtain enough tissues in any one lab, to conduct thoroughly sound statistical analysis on genetic variations that only occur in a certain percent of the population, the researchers banded together to pool their brains, literally.  All the brain samples and data from each of the participating labs were used to look for associations between genes, brain size, disease risk and IQ test ability.  Without the collaboration, the project would not have been possible. The nature of the work and the extent of the collaboration has attracted hundreds of financial contributors that has ensured the success of the work.
So does this mean we should kick back as parents and let nature take its course?   Not at all.  Intelligence is only useful when harnessed appropriately, and usually (with notable exceptions), that happens through the cultivation of good study habits and the development of some level of self- discipline. When I was doing my PhD, someone told me that it would require one third pure hard work, one third organizational skills and one third smarts.  I never forgot that, and found it to be just about spot on not only for my PhD, but for pretty much every piece of work I've done since. Intelligence is only part of the picture.

[JOURNAL REFERENCE-Jason L Stein et al. Identification of common variants associated with human hippocampal and intracranial volumes. Nature Genetics, 2012; DOI: 10.1038/ng.2250]

Thursday, April 5, 2012

Sunday, April 1, 2012

Another slice of cake?

I'm watching CBS 60 minutes with Dr Sanjay Gupta telling us how sugar is poisonous and speaking to a doctor who is recommending that men eat less that 150 calories worth of added sugar per day, while women eat less than 100.  The report is interesting; the effects of just s sip of soda stimulates the same part of the brain as hard drugs like cocaine, and continued consumption of sugar lead to a tolerance similar to that experienced by drug addicts. In other words, the more  you eat, the more you are driven to eat.  The chemical at the heart of this is not picky.  However we get dopamine to release from brain cells, be in sex, drugs or rock and roll or now... sugar, we are driven to need more.   OK, so we eat a lot of sugar. So what?  As long as we reduce our fats, red meats, bacon, chips etc, we are basically OK- correct?  As long as we control our weight somewhat, and lay off the chips we should be fine- right? Not even remotely.  A study being discussed on the show, took young adults and carefully controlled their diets for a period of time while monitoring their physiology and biochemistry.  They had blood drawn and were scanned throughout the study period which had them eating a non-added-sugar diet for the first few days of the study, followed by a diet with 25% of their calories in the form of sugar; still a relatively low amount of sugar by American standards (on average we consume about a third of a pound a day).  Blood samples were drawn every 30 minutes and the added- sugar consumers showed significant increases in small dense LDL cholesterol (the bad kind that clogs the arteries) within two weeks of eating the diet with 25% sugar.   For those old enough, you might remember that in the 70s the government restricted fat in the diet.
There was a short term benefit, likely due to increased awareness of dietary causes of disease and the number of people who reduced their intake of saturated fates.  However, the effect was not sustained.  Doctors not he show suggested we have replaced that fat with carbohydrates, and refined sugar in particular.  As one researcher pointed out, food without fat tastes like cardboard, so the food industry upped the sugar content to keeps palates satisfied.  Now, cardiovascular disease is back on the increase and our children may be the first generation to have a lower life expectancy that their parents.

So the sugar in our diet does as least as much harm to our cardiovascular health as fat, and maybe more. But the story doesn't end there.  Obvious effects of increased sugar are obesity, metabolic syndrome, and diabetes, and all of these diseases have peripheral effects.  Less obvious is the effect of sugar on some cancers. Because sugar stimulates increases in insulin, it also catalyzed the growth of certain types of cancers.  Almost a third of common human cancers contain insulin receptors that circulating sugar latches onto and triggers the tumor cells to take up the glucose to use for cell growth.  Basically the tumor cells highjack our blood sugar and uses it to feed itself and grow.  Exactly whether the sugars in the blood cause the tumor to begin or just nudge it along once it has become established makes no difference.  Sugar is good news for cancer, and bad news for us.

There is much more to the sugar story that I'll save for other blogs but as we think about how to balance our diets, it's worth thinking about the role of the food industry in our food choices.  Since I still have the TV on, I'm catching a few ads I haven't seen before.  In one, Con Agra is encouraging us to buy their products and is promising one meal for a hungry child for ever specially marked package we buy.  This sounds incredible and I am sure there is good will behind the gesture. Certainly, there are too many hungry kids in America today. However, the foods that Con Agra is asking us to buy includes Snack Paks, frozen chicken nuggets, Chef Boyardee and others, all of which are high in sugar.  We buy and eat a package of processed food that will go a little way towards poisoning us (some might think that's too strong a word but based on what I have read and hear, I don't think so) and in return Con Agra will feed a child.  Does this make anyone wonder exactly how they will be feeing that child?

And finally, as I complete this blog, I just saw a fantastic commercial on the TV with a diverse group of vibrant people stripping open their coats and cardigans to unveil bright red shirts with 'I'm unique', I'm A Vailable, I'm a dreamer....etc, as they run, walk, dance, around some city. It seemed like such a positive commercial, celebrating all that is good in the world- courage, difference, creativity.  Imagine my disappointment when I realized what the ad was for.   Dr Pepper.  Ugh.