Archives for 2010

Warning about Potential for Intestinal Blockage by Juicing Whole Citrus Fruit!

Today I had a patient who had recently been admitted to hospital with a painful and frightening intestinal blockage. I delved and learned that she had been juicing vegetables and adding one or two whole lemons and sometimes a whole orange to the juicer. I was telling a colleague who had suffered the same experience although didn’t have to be actually admitted to the hospital and realized he had also juiced two lemons the day before. Please be aware that bezoars (the technical word for a mass that forms and can block the intestinal tract) can form from the white pith of citrus fruit.  These are sometimes called phytobezoars to distinguish them as having a plant origin.  You need a separate citrus juicer to avoid this happening!  Please pass this information on – it is especially relevant for anyone who has previous gastric surgery.

See a full report – Bezoars and orange pith Report

The value of smart health assessment

Despite high hopes of genome wide assessment studies providing useful knowledge the results have been disappointing to say the least. Except for rare genetic variations the chronic diseases that are amenable to diet change are elusive using this technique alone. That is why it takes a validated questionnaire format to determine family health history and current health status to make meaningful recommendations. Please visit www.thednadiet.com and answer the questionnaire to receive your free recommendations.

Is Polluted Air a trigger for Obesity?

Stress of many types appears to be linked to obesity apparently due to its link with inflammation.  Researchers at Ohio State University have identified another source of obesity related stress as polluted air.   Mice exposed to particulate air polution (seven times higher than typical ambient air in Columbus, OH) gained weight whether they were on a normal diet or a high fat diet.   A study investigating the link of polluted air early in life with overweight and obesity looked at mice over a period matching childhood in humans.  The mice also developed insulin resistance and had higher levels of a marker of inflammation TNF-alpha. Pollution may act as a trigger for obesity like other stressors. If so, this may be yet another reason why moving to urban areas is associated with weight gain.

Source:  Arterioscler Thromb Vasc Biol, Dec 2010; 30: 2518 – 2527

Is your bedroom TV making you fat?

Thought provoking study suggests that having a bedroom that isn’t completely dark such as sleeping with the TV on may be linked to weight gain and insulin resistance. Simple remedy that may be effective in helping with maintaining a healthy weight is to remove the TV from the bedroom! Light-dark cycles are known to be associated with melatonin release and this in turn is associated with tryptophan uptake in the brain. Tryptophan is an unusual amino acid and is taken up by the brain most rapidly when other amino acids circulate at lower levels such as after a carbohydrate only meal – maybe its not just the TV light but maybe that triggers cravings for soda and chips too. This study looked at mice (admittedly not humans but easier to control!) and found that exposure to a relatively dim light at night over 8 weeks caused a 50% greater weight gain than in mice who had a standard light-dark cycle.

French researcher J Le Magnen back in the 1980’s described fat building (lipogenesis) in association with dark cycles of rats contrasted to fat burning (lipolysis) during the light cycle. His findings were controversial at the time but maybe we should look again at how obesity may be not just about what we eat but how well we sleep.

#mce_temp_url#

“Neurobiology of feeding and nutrition” by Jacques Le Magnen

Academic Press, 1992

Are we any closer to obesity gene therapy? Maybe a little

Two new studies published in Nature Genetics http://www.nature.com/ng/index.html move us closer to identifying gene variants that increase risk of obesity. 18 previously undescribed regions included and confirmation of 14 other regions associated with BMI (Obesity is a BMI of 30 or greater). Unfortunately this doesn’t predict obesity any better than a good family health history. It isn’t the genes that are causing the current epidemic of obesity but how we are adapting to our current environment (fast food 24/7 and much less physical activity).

Do genes blog?

New research suggests that groups of genes talk to each other and pass the message down to next generations of cells. This is being described as “conditional memory” by Georg Fritz at University of Cologne and reported in MIT’s Technology Review’s Physics ArXiv blog.

http://www.technologyreview.com/blog/arxiv/25775/

Reflections on DNA Complexity

DNA over simplified or more complex?

In 2001 deciphering the human genome was thought to be a simple description of the parts list of a cell. Back then we thought simple translation of DNA would explain most of life and that each protein was the result of DNA being copied into RNA and then into amino acids and packaged as proteins. At that time I drew a picture attempting to describe that there would probably be much more complexity and variety. In my job as a nutritionist who sees many oncology patients it was clear to me that cancer cells were different by definition. I wondered why there wouldn’t be many other cells in our body in the process of deciding if a mutation or change in the DNA would remain or be edited out? Why wouldn’t our daily interactions with the outside (and inner) worlds affect this? Also, as we age wouldn’t these interactions impact and modify the text of our DNA like a copy editor(s)?

Learning the DNA complexity

Today we are learning that complexity is much more likely than simplicity in any of our explanations about DNA. First of all, did you know we have two types of DNA not just one? Ancient integration of bacteria is thought to be the reason why we have mitochondrial DNA not just nuclear DNA. These are single strands located in the power houses of each cell and found in huge quantities in liver and other highly metabolically active cells. With such a high level of turnover it makes sense that there would be a lot of modifications simply because of inaccurate or inefficient copying and repairing. Another factor is the addition of regulating “tags” such as methyl groups, called epigenomics. This is not well understood but apparently very important. Another reason that simple explanations no longer work is that it appears that rather than being randomly assorted, DNA strands in each chromosome show a wide variety of selection with some being determined by evolutionary pressure and whether of paternal or maternal origin. This is called imprinting.

Level of complexity

Some people find this level of complexity simply too much to ponder – rather like thinking about the vastness of our universe (part of a larger multiverse). Linear, logical thinking no longer describes the sophisticated biological systems that so elegantly explain life. A leading to B leading to C just doesn’t do it any more. But, we don’t need to understand astrophysics to appreciate a sunrise or sunset. I am in awe of how each time a discovery is made about genomics there is further complexity to impress us. The challenge from my perspective is how to drill down to what is meaningful and valuable for improving our health without being overwhelmed and switched off to the whole process just because it is so detailed.

Another layer of DNA

Another layer to add to this challenge is how each of us approaches discoveries from different personal histories and personalities. What I find fascinating may just be plain boring to someone else.

  • I would love to hear from you – what do you think about it all?
  • Are you uncomfortable or stimulated by this level of complexity?
  • Do you see chaos or order or perhaps both at the same time in some kind of dynamic equilibrium?

Body fat as a safe storage site for toxins?

The late Roslyn Alfin Slater, PhD, one of my mentors at UCLA, noted that adipose tissue is a relatively safe place to store toxins that aren’t readily removed (by liver or kidney detoxification processing). A recent examination of NHANES (National Health and Nutrition Examination Survey) showed a highly significant correlation between six environmental pollutants in serum and weight change. A second study found similar changes in 39 obese individuals subjected to a 15 week low calorie diet and looking at 26 organochlorine compounds in blood and body fat (subcutaneous). This underscores the importance of supporting liver and kidney detoxification processes by eating a high fiber, fruit and vegetable rich diet and avoiding environmental pollutants for health.

Int J Obes (Lond). 2010 Sep 7

Int J Obes Relat Metab Disord. 2000 Oct;24(10):1272-8.

Sit less – move more but it may be all in the genes!

First we learn that it is less about what you do rather how little you sit down that affects your health and mortality. Sit less, move more! (Patel, et al. Am J Epidemiol 2010:172(4)419-429)
Another study (with mice not humans) indicates that voluntary exercise is highly heritable meaning wanting to sit more may be something you are programmed to do (Garland, et al. Proc Roy Soc 2010, DOI 10. 1098/rspb2010,1584). Even if that is the case for humans (and many rodent behavior studies don’t pan out when applied to humans) then it simply means for those of us who find it hard to get to the gym we will still benefit if we get up, pace around and are just more active. “Use it or lose it” as Jack Lalanne would say – one of my heroes who is still amazingly active both physically and mentally in his 90’s. Go Jack!

Experimenting in the Kitchen

Listening to Jeff Potter, a software engineer and author of “Cooking for Geeks” as he demystifies food preparation as Ira Flatow’s guest on Science Friday. Who knew that “Total Textural Preference” describes how one of the proteins in meat (Myosin) changes shape before the other one (Actin) at 120 degrees and apparently we like that?!
Did you know that when it is hot enough to fry an egg it means the sidewalk is at least 142 degrees? I also learned that sugar melts at 367 degrees. I forgot that food science was so interesting. My undergraduate courses never held my attention like that but perhaps it is all in the delivery and Jeff is a self professed kitchen geek. I can’t wait to read his book and start experimenting in the kitchen.