GMOs and Indian Suicides

Just as Keith Kloor seems to put the issue (or myth as he calls it) to rest in an article recently appearing in Issues in Science and Technology, now comes a new article in the journal Globalization and Health suggesting a link between farmer suicides in India and farmer debt, a finding that will no doubt re-ignite the argument that adoption of GMOs caused suicides.  Indeed, the authors conclude the article by saying

Some observers have suggested that the introduction of genetically modified varieties of crops since liberalization has considerably worsened the situation . . .

 For background on the controversy, see this Wikipedia page.

I personally didn't find the new analysis in Globalization and Health as being particularly compelling, and it does NOT, as some reports of the study have suggested, provide "causal links."  The authors estimate simple linear regressions specifying suicide rates (suicides per 100,000 people per year) in a region (or state) as a function of indebtedness (measured as the % of farmers in a region that have taken out a loan in excess of $5).  

I don't doubt that indebtedness and suicides are correlated, but isn't it possible that there is some unobserved factor (or factors) causing both?  Macro-economic conditions? Social-cultural factors within a region (there are no regional fixed effects in the models)? A shift in time preference caused by other unobserved factors? If this sort of endogeneity exists, the estimates are biased.  Although the authors have 5 years of data on their dependent variable, they only have one measure of "indebtedness" at a single point in time, and assume it is the same for all time periods; thus, they cannot include year by region fixed effects.  This means that they cannot separate other regional-specific shocks to suicides from indebtedness effects.

For a more complete and through analysis of the issue, I suggest the papers by Guillaume Gruèrea and Debdatta Sengupta, which first appeared in a working paper with IFPRI and then later in a more condensed form in the Journal of Development Studies.


Does information on relative risks change concerns about growth hormones?

Consumers often express concern about the use of growth promotants in animal agriculture.  In the beef industry, various growth hormones are administered to cattle to improve and speed the rate of growth (and some would say, improve the sustainability of beef production).  Upwards of 90% or more of feedlot cattle in large feedyards are given hormone implants.

Some consumers are fearful about the safety effects.   For example, the EU has banned imports of hormone-treated cattle from the US for over 20 years (a policy which probably has more to do with protectionism than actual safety concerns).  Other people have argued that these are the cause of decreasing puberty age of girls (which the data doesn't support).

As a result, many in the beef industry have have tried to communicate the fact that the risks from hormones are small to non-existent, and are much smaller than the risks from hormones in everyday foods.  The normal comparison is between how much estrogen is in a hamburger from an implanted steer or heifer vs. the amount of estrogen in other foods like soybean oil or cabbage.  Examples of such discussions appear at BeefMyths.orgUS Meat Export Federation, the NCBA, and extension facts sheets from Michigan State University, University of Nebraska, University of Georgia, and many others.

Circulating on the web a while back were some discussions of using some visual strategies to communicate the relative risks from estrogen used in cattle implants.  For example, here is one blog discussing the use of M&Ms to convey the risks.  

The question I wanted to know is whether any of these sorts of communications actually has any impact on the people for whom it is intended.  

In the most recent issue of my monthly Food Demand Survey (FooDS), we sought to address this issue.  1,017 respondents were randomly allocated to one of three information groups or treatments.  In the first no-info group, respondents were simply told, “About 90% of feedlot cattle are given added growth hormones to improve the rate of growth.” And then, respondents were asked, “How concerned are you about the use of growth hormones in beef production?”  

For the second group text-only group, written text was added to convey relative risks of hormone use.  Prior to being asked level of concern, subjects were told, “About 90% of feedlot cattle are given added growth hormones to improve the rate of growth.  The added hormones add about 3 extra nanograms (a billionth of a gram) to a 3 oz serving of beef.  For comparison purposes, the amount of estrogen that naturally occurs in 3 oz of the following foods is: potatoes (225 nanograms), peas (340 nanograms), cabbage (2,000 nanograms), soybean oil (170,000 nanograms).”  

Finally, the third visual+text group was given the same written text but was also shown the above visual illustration using M&Ms allocated to different jars.  

Participants in all three groups answered with their level of concern on a five-point scale (1 = very unconcerned; 5=very concerned).

Information on relative risks caused a small but statistically significant reduction in the level of concern.  The mean levels of concern, on the 5-point scale, were 3.93, 3.71, and 3.66 for the no-info, text-only, and text+visual information groups.  

Without any information on relative risks, over 71% of respondents indicated that they were either concerned or very concerned.  Textual information reduced that frequency to 66%, and visual+text information further reduced the percentage of concerned respondents to 63.6%.   

What do consumers think of the FDA's new nutritional labels?

We've known for a few months now that the FDA has been planning to revise and update the nutritional labels appearing on packaged foods.  

There has been a lot of discussion in the news about the merits (and demerits) of the label.  But, what do consumers think?

In the most recent issue of my monthly Food Demand Survey (FooDS), we directly asked consumers what they thought.  Here is a screenshot of the question we asked (note: the order of the labels was randomly varied across surveys).

The images were taken from an FDA website showing an example of the new, proposed label along with an example of the current label.

We have data from 1,016 respondents (data was collected last week); results are weighted to be demographically representative of the US population with a sampling error of +/- 3%.

We found 26% said they preferred the current label, 57% preferred the new, proposed label, and the remaining 18% said they were indifferent.  

Food Demand Survey (FooDS) - April 2014

The newest release of our Food Demand Survey is now up.

Willingness-to-pay for most meat products was up this month, and consumers reported that they anticipate buying about the same amount of chicken, beef, and pork as in previous months despite expectations of higher prices for all three.  

Reported expenditures on food at home and away from home were down in April relative to March.  

Consumers reported hearing more about Salmonella and E coli and less about pink slime and lean fine textured beef in the news in recent weeks as compared to last month.  Consumer concern dropped the most for GMOs and E. coli and rose the most for beta-agonist and bird flu.

We added a couple interesting ad-hoc questions I'll blog about in a separate post.  

What we think about a label may be as important as the label itself

What believe about a food's ingredients may have a biological effect on our bodies above and beyond the actual nutrient content.

That is the conclusion from a study published in the journal Health Psychology, which was recently covered by Alix Spiegel at the NPR Health blog.

The authors conducted an experiment in which they fed the same 380 calorie milk shake to two different groups of subjects.  The first group was lied to, and were told (via a label) that the shake was a "sensible" 140 calories.  The second group was also lied to, but in the opposite manner: they were told (via a label) that the shake was an "indulgent" 620 calories.  

The researchers measured the levels of a hormone, ghrelin, before during and after the label experiment.  Ghrelin levels are particularly interesting to monitor because they regulate metabolism and help signal hunger or satiety.  After eating a big meal, ghrelin levels fall, signalling us to stop eating.  Eat a light meal, and ghrelin levels remain high, signaling us to eat more.

The authors found that people consuming the "indulgent" labeled shake experienced a significant increase in ghrelin just before consumption (in anticipation) and then a significant decline in ghrelin after consumption.  The change, the authors argue, is consistent with that typically observed after eating a big meal.  By contrast, the level of ghrelin was flat before and after eating the "sensible" shake.   All this is in spite of the fact that the two shakes were exactly the same in every way except for the labels!  

The authors were quoted as saying:

Labels are not just labels; they evoke a set of beliefs

and that labels might

actually affect the body's physiological processing of the nutrients that are consumed.

One way to interpret the results is to place them in the category with other "behavioral biases" in the behavioral economics literature: another piece of evidence that people do not behave rationally.  I see it a bit differently.  The results suggest a kind of "extra" rationality.  Mind over matter.  What we think might well trigger how our body responds.  Marketers might influence what we think about foods, but we have some control over the process too.  

Now, if I can just fool myself into believing that small lunch salad is actually one of the Carl's Jr. "Indulgent Salads", I'll feel fuller and lose more weight! 

The study's sample size was small (N=46), probably because to measure ghrelin they had to insert an intravenous catheter to draw blood at repeated intervals.  So one proceed with caution until more work of this sort is done.  Still, very interesting nonetheless.