Saturday, August 31, 2013

Have you ever washed your reusable bags?

Up until recently I hadn't ever washed my reusable grocery bags, not because I didn't think it was necessary or a good idea, but to be honest, the idea just hadn't crossed my mind.  Since Alameda County now charges for bags, and word on the street is that Contra Costa county will also soon be charging, it seems I will be using more and more reusable bags in the near future.

Awhile ago Mr. L sent this article to me about the need to wash reusable bags.  I promptly washed our bags, and bookmarked the article for further thought and study.  Larson cites a study published by law professors at the University of Pennsylvania and George Mason University.  This study claims to have found a 46% spike in San Francisco deaths during the 3 months immediately following the county wide plastic bag ban in October 2007 (2).  Yikes!  That seems pretty terrible.  However, either I'm being incredibly dense, the numbers in this study are a little sketch, or lawyers have a very different way of reporting numbers, but regardless, after looking at this study a few times this week I wasn't able to grasp what was actually going on.  I'm a little uncomfortable with the way the authors compared the before and afters, and since I'm not actually positive of anything, I'll simply be setting this study aside and looking at two published articles that are applicable to this discussion.

Perhaps many of you have been washing your bags for years-- if you think about it, it really is common sense.  However, one study randomly interviewed shoppers and sampled reusable bags in California and Arizona (3).  They found that reusable bags are seldom, if ever, washed, and that most bags had large amounts of bacteria, about half had some coliform bacteria on them, and 8% had e. Coli on them.  The good news is, is that these authors report a >99.9%  reduction in bacteria after washing the reusable bags (3).

Another article of note concerns a "point-source" norovirus outbreak on a soccer team (4).  After interviewing, constructing a graph of exposures, and calculating risks associated with different exposures for those who were sick and those who were not sick, it was determined that the likely cause of the norvirus outbreak among this team was a reusable grocery bag containing sealed snacks which were stored in the bathroom of the original team member who was sick.  As the authors point out, this exposes one good reason not to store food, or bags containing food, in the bathroom and the need to disinfect bathroom surfaces-- especially after someone has a stomach and intestinal bug.  However, they also point out that this, "illustrates one of the less obvious hazards of reusable grocery bags" (4).

I like reusable grocery bags for multiple reasons--they're often easier to carry, they're less likely to break, and they're less wasteful.  However, it now seems obviously important to me to wash these bags frequently and to practice good segregation by not putting meat in the bag one day and fresh produce in it the same bag the next day.

I'm curious though, have you ever thought about the importance of washing your reusable bags?

(1) Larson, L. E. coli Infections Spike After Plastic Bag Ban in California.  Food Poisoning Bulletin.   February 10, 2013. Accessed 8/30/13.

(2) Klick, J., and Wright, J.  Grocery Bag Bans and Foodborne Illness.  August 15, 2012.  Accessed 8/31/13.  

(3) Williams, D., Gerba, C., Maxwell, S., and Sinclair, R. Assessment of the Potential for Cross-contamination of Food Products by Reusable Shopping Bags. Food Protection Trends, (2011) 31(8): 508-513. Accessed 8/30/13.

(4) Repp, K., and Keene, W. A Point-Source Norovirus Outbreak Caused by Exposure to Fomites. J Infect Dis. (2012) 205 (11): 1639-1641. Accessed 8/30/13.

Friday, August 16, 2013


This last month has been a bit of a whirlwind for my family what with a camping trip, Baby's first birthday party (I guess I'll have to come up with a new alias for him since he's not a "baby" anymore), a quick trip to Los Alamos to visit family, and then more family visiting us.  But looking back, I'm thankful for each individual trip/event-- God has been so gracious and good to us to bless us with so much family who love us and want to be involved in our lives, wonderful friends to share a birthday with, and gorgeous scenery and the great outdoors to enjoy.  Despite short periods when I wished we weren't doing one or another of our trips, I know we will have fond memories for many, many, years to come.
Trinity Alps, California
Certainly one of the dirtiest camping trip I've been on!
A joint birthday party for three little friends, all turning one.
What are little boys made of?  why, Frogs, and Snails, and Puppy Dog tails, of course!
The cake was certainly squishy and fun...
...but it makes more sense that you're supposed to eat it if you have a fork!
Fun times with aunts!  So sad the times are few and far between
My parents' tree was knocked down by a hailstorm, so Mr. L got to use a chain saw and help remove it.
Beautiful Los Alamos ski area.
And last, but not least, a birthday visit from Baby's paternal grandparents.
Truly, we are blessed with so many things to keep us busy, and I am thankful!  I'm also thankful for, and looking forward to, having nothing major planned over the next several months. I'm sure there will be plenty of ordinary everyday things to occupy our time and to be thankful for.

Monday, July 22, 2013

Sunscreen {and the tension with cancer prevention}

I know everyone is probably sick of hearing about sunscreen by now, so I promise this is the last post about it.  There were just so many different aspects to cover-- many more than I had originally thought of.

The more I'm reading, the more I'm learning that skin cancer really is a concern, and I ought not to brush it off as something that doesn't affect me.  Melanoma rates are rising every year in the United States, and overexposure to sun, especially in youth, appears to be linked to an increased risk of developing cancer later in life (1).

If the the melanoma rates really are related to sun exposure, I'm curious what has changed.  For example, common sense would tell me that, in general, the population spends less time in the sun today than 100 years ago, not more.   But yet, the population certainly did not liberally apply commercial sunscreen 100 years ago (2).

I found a few interesting speculations for why sun exposure might be more dangerous today then it was in past decades, and I think this could contribute to the rising rates of skin cancer.  In The Five Paradoxes of Vitamin D (2)Chesney states that between 1600 and 1960 the skies in general where simply darker because of the amount of coal in the air.  Coal and coke were the primary fuel used to heat both homes and industry, and this contributed greatly to hazy skies, especially over cities.  However, between 1950-65 the types of fuels the world used diversified--populations starting using nuclear energy, hydroelectricity, and other non-coal hydrocarbons (2).  In the last several decades there has also been aggressive campaigns to reduce many kinds of emissions from industrialized countries and to promote "clean air".

Another environmental factor that might contribute  to the change of intensity from the sun is atmospheric dimming due to volcanic ash. Four catastrophic volcanoes erupted between 1815 and 1902: Tambora, Krakatoa, Santa Maria, and Mount PelĂ©e.  Tambora, which is in Indonisia, erupted in 1815 and was the most explosive eruption in 1300 years (170 times stronger than the Mt. St. Helens eruption in 1980).  The atmospheric dimming was so noticeable that the following year, 1816 ,is known as "the year without a summer".  Apparently, volcanoes in the 20th century have been less intense and the ash has been more localized which could be one reason dimming has fallen since 1990 (2).

One last environmental factor to consider when thinking about environmental changes is the presence of CFC's in the stratosphere.  When CFC's reach the stratosphere certain chemical reactions cause the depletion of the ozone layer. With the depletion of the ozone layer,  a higher number of UVB rays hit the earth (2) and this could contribute to an increased need for protection from the sun.

To be honest, I'm nowhere near an expert at environmental science.  One question I have about atmospheric dimming is that if it didn't start declining until 1990 (and I believe it's been a pretty gradual decline), then would that really contribute to the increase in skin cancer we see today?  As Mr. L pointed out, that would depend on how long it takes for skin cancer to develop.  Are the effects that noticeable within a 23 year window?  I just don't know enough about the etiology of skin cancer to answer this question.

So, to conclude this series on sunscreen and vitamin D, it appears that it probably is important to protect ourselves from the sun, but this doesn't diminish the importance of vitamin D.  Some studies have associated a deficiency in vitamin D with autoimmune disease, fractures, cancer, and cardiovascular disease (1). A prior NHANES suggested that low vitamin D levels were even associated with all-cause mortality (1).  When thinking about how I should ensure that my family receives enough vitamin D this is a big tension for me, since I prefer not to rely on supplements for essential parts of our diet, but I also don't want to significantly increase our risk of skin cancer (yes, there are dietary sources of vitamin D, but I think it's unlikely that we would get enough from our diet).

I do plan on being more consistent with sunscreen (since at least in one large study it didn't appear to be associated with vitamin D deficiency), but until I'm more convinced that moderate, non-sunburning sun exposure is a significant risk factor for developing skin cancer, I'm still not planning on slathering it on every day.

(1) Dart H, Wolin KY, Colditz GA. Commentary: eight ways to prevent cancer: a framework for effective prevention messages for the public. Cancer Causes Control. 2012 Apr;23(4):601-8. doi: 10.1007/s10552-012-9924-y. Epub 2012 Feb 26. Accessed 7/11/2013.
(2)Chesney, RW. The five paradoxes of vitamin D and the importance of sunscreen protection. Clin Pediatr (Phila). 2012 Sep;51(9):819-27. doi: 10.1177/0009922811431161. Epub 2011 Dec 12. Accessed on 6/3/13.
(3)Linos E., et al.. Sun protective behaviors and vitamin D levels in the US population: NHANES 2003-2006. Cancer Causes Control. 2012 Jan;23(1):133-40. doi: 10.1007/s10552-011-9862-0. Epub 2011 Nov 2. Accessed on 7/9/13.  

Friday, July 19, 2013

quick link, and happy weekend!

Happy Friday, dear readers! I'm looking forward to a fairly low-key weekend before a very busy next month or so starts for us. I hope you have a lovely weekend ahead of you too.

But anyways, I just found an article on the New York Times, Dear Parents: Please Ignore the Latest Research, and thought the message was timely and that you might enjoy the read.

Nicholas Day does a good job of highlighting the ridiculousness of letting our parenting decisions be too heavily influenced by what new research finds and what the media reports:
"Science works in small, boring ways. Findings have to accumulate, and they take their time to do so. They rarely arrive in a baby-manual-ready bundle, already replicated, with a massive data set backing up the conclusions. Unless you are a scientist doing infancy research yourself, a single study means very little. It has meaning inside the discipline; it has far less meaning inside the home."
One of the examples he uses is a recent psychology study that suggested that baby boys who used pacifiers were likely to have difficultly expressing emotion later in life.  Regarding this, Day says:
"This sort of study is almost always tentative and highly contingent. It’s a single data point in a very complicated matrix. Parents rarely recognize this. And you don’t have to wonder why. Here’s how the pacifier study was covered: “Parents who don’t want their baby boys to grow up emotionally stunted may want to pocket their pacifiers during the daytime.” Your call! If you want your boy to be emotionally stunted, feel free to keep using it! "
Basically, Day concludes that science is important and useful, but that we shouldn't let new sensational studies influence our day-to-day parenting (you should just read the article though, it's not that long).

To me, this article perfectly highlights the great need for God's wisdom and the Bible in parenting and decision making.  Science will continuously publish and discover new things about babies and children; however, in years to come, some of this research will be forgotten, some likely reversed,  and some confirmed as true. However, God's wisdom is timeless-- it's not new or sensational, but it is true.

Sunday, July 14, 2013

Sunscreen {protection methods}

Sunscreen is one of many ways we can protect ourselves from the sun, but it's not the only way.  Shade, long sleeves, and hats also work well in protecting us.  I was surprised to learn that people who tend to seek shade and wear long sleeves where more likely to be vitamin D deficient than people who reported regularly using sunscreen (1).  Part of the reason this surprised me is that for years I've thought in the back of my head that sunscreen was greatly contributing to the epidemic of vitamin D deficiency, but inasmuch as my reading has shown me, this is probably not the case.  

The CDC started The National Health and Nutrition Examination Survey (NHANES) in the early 1960's to conduct nation-wide surveys to gather statistics of various population groups and health topics.  In 1999 the program became an ongoing survey that examines about 5,000 people each year regarding emerging health and nutrition topics.   The data NHANES collects is available for researchers to analyse and use, or for agencies to utilize in evaluating and implementing health policy.  One example of NHANES data in use is the growth charts that doctors use to see how well babies and children are growing (2).

Between 2003-2006 NHANES collected data regarding sun protection habits and the levels of vitamin D in participants' blood.  Linos, et al., analysed this data and published a paper examining what they found (1).  Below is a graph from their paper that illustrates part of what they found-- that for all races combined, two factors, staying in the shade and wearing long sleeves, were significantly associated with lower vitamin D levels, while frequency of wearing hats or using sunscreen were not associated with lower vitamin D levels.

The NHANES data is a survey intended to gather information about the population at a specific point in time--this study design is called a cross-sectional study.  Cross-sectional studies are the simplest of all study designs, but also one of the weakest(3).  This type of study is often used to asses prevalence; for example, in this paper the authors measured the prevalence of vitamin D deficiency in different subsets of the population.  The major weakness of this design, however, is that because of the lack of any time dimension (all data is gathered at the same time) it is extremely difficult to establish any semblance of causality (3).  Because of this major design limitation we need to be careful not to make too strong of a conclusion from this study.

I think what they found is interesting-- I wouldn't have guessed that sunscreen was not associated with  vitamin D deficiency, but that shade and long sleeves were associated.  Although we certainly can not say that shade and long sleeves cause deficiency it is instructive to consider this association when thinking about our sun protection options.  We should realize that it's possible that protective clothing may be much more effective at protecting us from the sun than sunscreen-- this may be good or bad depending on what your goals are.

Although causality can't be established by this study, I still think it makes a fairly strong case that sunscreen is not single-handedly causing the epidemic of vitamin D deficiency.  For me, I think this means that I'll worry less about using sunscreen, but also that in certain situations I'll be more likely to seek shade, since that is apparently one good way to protect myself from overexposure to the sun.

Photo Credit: Sanny Hauck


(1)Linos E., et al.. Sun protective behaviors and vitamin D levels in the US population: NHANES 2003-2006. Cancer Causes Control. 2012 Jan;23(1):133-40. doi: 10.1007/s10552-011-9862-0. Epub 2011 Nov 2. Accessed on 7/9/13.  
(2) National Center for Health Statistics.  National Health and Nutrition Examination Survey 2013-2014 Overview: Let's Improve Our Health. Accessed on 7/11/2013
(3) Elwood, M. Critical Appraisal of Epidemiological Studies and Clinical Trials: Third Edition. Oxford: Oxford University Press, 2008.  p. 25-6, 46. 

Monday, July 8, 2013

"bundling" vs. sipping and snacking

Early in June I remembered that I had a dental radiology license that needed renewing by the end of the month, and in order to renew it, I needed 30 hours of continuing education (yikes!).  Thankfully, acquiring the hours wasn't as bad as I anticipated since I was able to finish them online during nap times and in the evening.

One of the courses I took, Interviews with the Experts, Key Topics in Dentistry Today, spent a few minutes talking about parenting and children's dental health.  Although nothing that Dr. Lott shared was ground breaking, I think some of it is worth sharing.

As a side note, unlike most of my other posts where I spend time examining published research, this post is different since I will only be summarizing "expert opinion".  Expert opinion is an important way that we know things, but it is not as reliable as certain other ways of knowing.  (Sometime I'll have to write a post about the hierarchy of evidence.)  For this reason, you won't find a list of references at the bottom--I'm simply reporting on one pediatric dentist's opinion.

With that disclaimer, one habit that greatly contributes to the demise of oral health is sipping and snacking.  I'm not particularly great at controlling this in my life (to be honest, I have quite a sweet tooth), but it truly is important.  As a mom, I certainly see the appeal of feeding kids food throughout the day to keep them happy and quiet (especially when under social pressure!) but as a former dental professional I cringe inside when I consistently observe it.

The concept that Dr. Lott talked about to combat sipping and snacking was the idea of "bundling".  If your child drinks juice or eats dessert, bundle it with the meal.  Don't eat lunch, let your child play for an hour, and then offer dessert, but let them eat it all at the same time.  Don't let your child sip on juice throughout the day, but instead, treat it as a part of their meal.  One reason this is so important is that your teeth don't care that much about how many fermentable carbohydrates (e.g. sugars, starches, fruits) they are exposed to at one sitting, but rather how often they are exposed.  Perhaps think of it like a cut that you get on your hand, if you wash it and then leave it alone it will get better much quicker than if  you don't wash it but instead irritate it every half hour and rub dirt on it multiple times during the afternoon.  Obviously the illustration only goes so far, but the point is that certain foods weaken your teeth, and prolonged exposure only exacerbates the problem.  (Mayo Clinic has a reasonable explanation of how tooth decay forms.)

Like most habits that we want to discourage in our children, it's important to take a look at what our habits are.  Take the sippy cup, for example.  Do you have an adult version of the sippy cup?  We know that it's best for the toddler to not carry a cup with juice in it around all day, but do I do this in my adult way? I prefer to sip on coffee throughout the morning, but really, I ought to bundle it with my breakfast, or at least drink it in one prolonged sitting when I'm doing my morning devotions.

When thinking about sipping and snacking, for me, it's not just the immediate disadvantages that bother me, but it's the habit that you're fostering, a habit that your child may struggle with for his entire life.

Thursday, June 6, 2013

Sunscreen {a historical perspective}

I've always thought that sunscreen smells bad, feels bad, and is just generally inconvenient. Since I also know that vitamin D is important for many reasons, and your body synthesizes it from the sun, I generally use the excuse of “getting my vitamin D” for not applying sunscreen as often or as liberally as recommended.

Since sunscreen season is fully upon us, I thought a post (or perhaps a series of posts)
looking at what the evidence has to say about sunscreen would be timely. Today we’ll start with a historical perspective.

In The Five Paradoxes of Vitamin D and the Importance of Sunscreen Protection, Russell Chesney takes time to look at the history and relationship between vitamin D and sunshine. Below is a short summary and review of his journal article published in Clinical Pediatrics.

Rickets, a vitamin D deficiency disorder, first emerged in England around the start of the industrial revolution and reached epidemic proportions by 1650. At first, it was puzzling that rickets was much less prevalent in the tropics and in rural areas, but as the link between vitamin D and rickets and the sources of vitamin D became known, this observation made sense. By 1930, it was well understood that vitamin D deficiency caused rickets and that there were 2 “sources” of vitamin D, a substance found in cod liver oil, and sunshine. Due to the nature of extreme latitudes, the coal in the air above cities to filter the sunlight, and the habits of city dwellers, it made sense that those who lived in cities would receive less sunlight, and therefore be more susceptible to vitamin D deficiency and rickets.

In 1931, The Children’s Bureau strongly advised parents to suntan infants and give them cod liver oil. At this time in history, the value of sunlight exposure was highly stressed, while there was little thought given to potential skin damage. (How far we have swung to the other side, when we now recommend little to no sun exposure for the first 6 months!)

Around 1985 it was observed that skin cancer rates were increasing. With this observation came the real fear of developing skin cancer from exposure to sunlight. Sun exposure recommendations therefore changed, and today the AAP and the American Academy of Dermatology recommend shelter form sun and liberal sunscreen use. However, adhering to these recommendations necessitates vitamin D supplementation by mouth in order to prevent deficiency.

It is interesting to me, but not surprising, that opinions of whether vitamin D should be absorbed from the sun or ingested through diet/supplements are highly influenced by the current opinion concerning the potential harmfulness of the sun.

It’s estimated that a large percentage of the United States is vitamin D deficient, and I’m curious if this could be related to our sun protection behaviors. Also, is there any reason that the sun might be stronger today and consequently require more “protection” from than in the past? Or is this obsession with sun protection just a result of our safety obsessed society? Next week, I hope to address some of these questions.

But enough of me talking, what is your relationship to sunscreen? Do you practically hate it too?

Chesney, RW. The five paradoxes of vitamin D and the importance of sunscreen protection. Clin Pediatr (Phila). 2012 Sep;51(9):819-27. doi: 10.1177/0009922811431161. Epub 2011 Dec 12. Accessed on 6/3/13.