The SciFiles #3: 20 Years Later, Genetically Modified Salmon Approved

I had to write a short, informative, and “unbiased” piece for my work the other month. Posting it here, since it took me a good chunk of the day! 🙂

On November 19th, 2015 the U.S. Food and Drug Administration (FDA) approved the first genetically modified (GM) animal intended for human consumption- AquAdvantage Salmon. The agency reached its decision after 20 years of evaluating research and opinions from a range of sources, including research submitted by the developers themselves (AquaBounty Technologies, a small company in Massachusetts), available peer-reviewed scientific literature, and comments from public hearings and the Veterinary Medicine Advisory Committee. Ultimately, the FDA concluded that the product is safe for humans and animals to eat.

Screen Shot 2015-12-10 at 8.00.24 PM.png
Both GM and regular Atlantis salmon will end up being the same size, but the GM one will grow FASTER (thus, on the pic, it is larger at the SAME age).

What makes AquAdvantage Salmon unique is that it grows 40% quicker than non-modified farm-raised Atlantic salmon. This effect is achieved by inserting fertilized Atlantic salmon eggs with 1) a growth hormone gene from the Pacific Chinook (or “king”) salmon, and 2) a genetic promoter from an ocean pout fish. This promoter keeps the added gene active all year round, while salmon’s own growth hormone gene is only active in the warmer months. These modifications will not lead to any measurable differences in the GM salmon’s look, taste, or it’s ultimate size and nutrition value, but they will make it grow to adult size quicker.

Image borrowed from article by Leslie Baehr

Product Benefits

Clearly, growing almost twice as fast is a considerable economic advantage to fish farmers. In addition, the current practice of catching Wild Atlantic salmon for human consumption is not sustainable as the world’s oceans are already seeing declining fishing yields. Another environmental advantage is a reduced carbon footprint of the fishing industry, as the modified salmon can be grown in captivity close to human populations and reduce transportation costs (in the U.S., 95% of salmon is imported). To the consumer, these factors would potentially result in lower prices and an opportunity to make salmon (a healthy protein choice, according to the U.S. Department of Agriculture) a more affordable part of their diet.

Public Concerns

While the FDA has concluded the GM salmon safe to eat, consumers and public interest groups raise important concerns. One potential issue is the fish escaping into the wild and affecting the environment (e.g. competing with wild salmon for food or mating with it and introducing new hybrid species). The escape scenario, however, is highly unlikely when considering the “multiple and redundant” safety measures in place. First, GM salmon can be raised only in land-based contained tanks in Canada and Panama. Second, there are multiple physical barriers placed in both the tanks and plumbing to prevent the escape of fish and eggs. Lastly, the AquAdvantage salmon is female and sterile, making interbreeding highly unlikely.

In terms of human health implications, Genetically Modified Foods (GMOs) already raise concerns among consumers as people consider possible long-term effects from such a novel technology: 57% of Americans surveyed in 2015 said GMOs were unsafe and 67% stated that scientists do not clearly understand their health effects (Pew Research Center). In contrast, the international non-profit organization AAAS (American Association for the Advancement of Sciences) is more confident about our current state of knowledge, stating that:

“the science is quite clear: […] consuming foods containing ingredients derived from GM crops is no riskier than consuming the same foods containing ingredients from crop plants modified by conventional plant improvement techniques”.

(Full statement: While GM salmon is now approved for sale (though it will take about two years to reach the market), some retailers have already pledged to avoid the product (e.g. Whole Foods, Trader Joe’s) reflecting such consumer worries.

The Labeling Question
One aspect of the FDA ruling saw particular opposition from public groups: GM salmon will not require labeling. While the FDA issued two recommendations for manufacturers to voluntarily label the product, the agency can only require additional labeling if a material difference is present between a GM and non-GM salmon (e.g. differences in nutritional profile). As no such material distinction has been found, a mandatory labeling might incorrectly imply an essential difference between the two.Screen Shot 2015-12-10 at 8.03.09 PM.png

Another issue with requiring labeling is that a “genetically modified” food is not necessary a meaningful category, and the choice of foods to include in it would be quite arbitrary. After all, humans have been modifying the food supply in various ways for quite some time. This includes “wide cross” hybridization resulting in plants not found in nature (including “heirloom” plant varieties often perceived as more “natural”). Another example is radiation and chemical mutagens that are used on seeds to generate new strains (e.g. a Ruby Red grapefruit, which can carry the “organic” label, was created via mutation due to radiation exposure). In comparison to these methods, genetic engineering is arguably the most precise and predictable technique at the moment.

As a consumer, you have a chance to read and comment on the FDA’s proposed guidelines for the industry’s voluntary labeling of GM salmon until January 25, 2016: FDA Regulations

The SciFiles #2: To Fish or Not to Fish?

Is it end of October already??

My ambitious plan to post simple summaries of cool research studies every Friday did no go as planned this Fall. Not only have I traveled internationally to collect data (dissertation, here I come!), but I also have 5 fantastic undergraduate apprenticeship students “working” in my lab this semester. So- a lot of time has been spent on training, learning how to train, and organizing/cleaning/analyzing the data they help collect for my work. 

Nevertheless, it’s time for another post.

Have you heard that fish is healthy for you? That Omega 3s, the “good” fat, is crucial for health? Or have you heard the opposite and are totally confused?

It wouldn’t be a surprise if you were.. Perhaps you’ve seen Screen Shot 2015-10-21 at 4.04.07 PMnews posts like this ->

In my interviews with folks in US and eastern Europe, the conversation includes”healthy fats” quite often. Everybody “knows” fish is healthy and we should all be trying to eat more omega 3 fats that are abundant in fish products for a healthy heart.

Yet in the last several years, many online sources reported on studies that refute these claims.

In this post I’ll briefly summarize a 2014 paper by Grey & Bolland. I believe you can even access it for free by clicking here.

Full reference: Grey, A., & Bolland, M. (2014). Clinical trial evidence and use of fish oil supplements. JAMA internal medicine, 174(3), 460-462.

What Grey & Bolland did was look for the best scientific work on the topic of omega 3 fats and how it affected sales of these supplements. Grey&Bollard summarized18 randomized clinical trials (between 2005 and 2012) that were published in high impact journals (=highest quality journals respected by the scientific community). Randomized clinical trials (RCTs) are considered the gold standard of research and present the highest level of evidence, so if you’re going to look at scientific support for any idea- clinical trials are the way to go!

What did those 18 studies show: well, only 2 studies reported benefits: a 2007 RCT on ~18000 people and using EPA for major coronary events, and a 2005 meta-analysis of RCTs on ~20000 people looking at effect of omega-3 oils and mortality. The other 16- no benefit… Fish oil sales? In the US between 2007 and 2012 fish oil and omega 3 supplements increased from $425 to $1043 million (!). Similar sales pattern were seen in England and Australia+asia. Technically, that’s not logical- if randomized clinical trials are the best and most robust type of scientific evidence, shouldn’t it influence current practices? The authors write:

“Since 10% of adults in the US take an Omega-3 or fish oil supplement, most commonly for heart health or to lower cholesterol, the null results of 9 of the 10 RCTs and 5 of the 6 meta-analyses studying cardiovascular disease  might have been expected to influence use”

I have pulled up the 2005 meta analysis- one of 2 studies from the review that showed benefit to supplementation- to get a bit more detail on the results. Studer et al (2005)* analyzed 97 studies to examine the safety & efficacy of various lipid-lowering interventions using mortality data (= they looked at lipid-lowering supplement/drug use and how often people who took them and didn’t take them die. The separated deaths into 1)either from all causes, 2)cardiac events, and 3) noncardiovascular causes). Such large-scale analysis of these randomized controlled trials is a very important tool- it allows to look at the overall benefit of interventions. This meta-analysis found that two supplements/drugs had reduce risk of overall and cardiac mortality (deaths from all causes and deaths from cardiac events specifically): statins and Omega-3 fatty acids.

Sounds wonderful, but again: it was only 1 of the 2 studies that showed statistically significant benefit of Omega-3s, while the other 16 did not. (statistically significant= meaning something happened Not by chance alone)

* Full reference:Studer, M., Briel, M., Leimenstoll, B., Glass, T. R., & Bucher, H. C. (2005). Effect of different antilipidemic agents and diets on mortality: a systematic review. Archives of Internal Medicine, 165(7), 725-730.

So why do more people continue taking the supplements? Well, first of all, we can assume the public doesn’t read original studies and can be victim to “industry spin”. The “spin” used by industry is a strategy to hype findings and distort the results of clinical studies. Wang et al. (2014) in fact looked this: they analyzed 47 supplements industry press releases & 91 non-industry press releases in response to 46 clinical studies of supplements (published between 2005 & 2013). Result? 100% industry press releases contained “spin” while only 55% of non-industry media pieces did. Industry press releases also reported less on study details – outcome, sample size, effect size- specifically for studies that found no benefit of supplements.

Full citation: Wang, M. T., Gamble, G., Bolland, M. J., & Grey, A. (2014). Press Releases Issued by Supplements Industry Organisations and Non-Industry Organisations in Response to Publication of Clinical Research Findings: A Case-Control Study.

So why else? Well, omega 3 supplements aren’t terribly expensive and people don’t associate them with any RISK, so it makes sense that folks would rather be “on the safe side” and take them. Also, the belief that these fats are “good” can be rather long-term and hard to change- I remember my childhood friends in Ukraine suffering through spoonfuls of fish oil given by their parents. So having a strong long-term belief that fish oils/omega 3s are beneficial can create confirmation bias: looking for evidence that you already agree with and dismissing new research that doesn’t fit your view.

Lastly.. how can fish fat not be beneficial? While I, of course, can not answer that question, here is an interesting piece of theScreen Shot 2015-10-22 at 12.20.39 PM puzzle- genetic adaptation. While I was preparing for a lecture on evolution and human diet, I saw a fascinating research piece at the National Institutes for Health website. Originally, the focus on fish oils came from studies with the Inuit and they seemed very healthy on their traditional fat-rich diets (fat coming from marine sources). So it was thought that fish oil would have a protective effect against cardiovascular disease.. But Dr. Nielsen states:

“We’ve now found that they have unique genetic adaptations to this diet, so you cannot extrapolate from them to other populations”; “A diet that is healthy for the Inuit may not necessarily be good for the rest of us.”

Access full article here.

To supplement or not to supplement, then?
Looks like it is not clear whether dietary supplements with omega 3 fats really influence deaths from cardiovascular causes (strokes, heart attacks) or other causes (cancers) in the population. Yet there is also no evidence that we need to advise people to stop taking these supplements. I suppose it doesn’t hurt..unless it hurts your wallet too much.. Your wallet deserves some good support coming from a good number of randomized controlled trials. 😉

The Sci Files #1: Importance of Carbs in Human Evolution

Note: This Fall I decided to attempt even more science communication! The Sci Files (imagine the x files theme playing) will be a collection of health & food-related research articles that I summarize in plain(er) language. I became quite passionate about breaking down hard-to-understand research for the public audience and I’ll try to do my best, considering I’m no expert! Yet 5 years of graduate courses- statistics, research methods, nutrition psychology, evolution & medicine- at least give me skills to understand a lot of the material that might be overwhelming to a lay reader. I will try to keep the summary to one page (~500 words), possibly followed by extra material that could be interesting 😉

For the first Sci File, i’m looking at a paper discussed yesterday during a lecture on the paleolithic diet. It’s published in 2015 in The Quarterly Review of Biology and the title intrigued me “The Importance of Dietary Carbohydrate in Human Evolution”. I’ve heard multiple talks on how the various “paleolithic” diets could have included starchy foods, but I didn’t think they were substantial parts of such diets.
Original paper: Hardy, K., Brand-Miller, J., Brown, K. D., Thomas, M. G., & Copeland, L. (2015). The importance of dietary carbohydrate in human evolution. The Quarterly Review of Biology, 90(3), 251-268.

Short summary:  

Apparently, you can delete the “NO” and still keep calm 😉

The authors propose that carbohydrates- particularly cooked high starch plant foods like tubers & roots- were essential in the evolution of our species- especially for the quick expansion of the human brain. They support this by showing that (1) critical development of this large glucozse-hungry organ required digestible carbohydrates, and eating cooked starch would really increase this energy availability to the brain (+ other glucose-hungry tissues such as red blood cells and the developing fetus).

They also show that the mutation in the enzyme for digesting carbs (salivary emylase, AMY1) co-evolved with both cooking and eating starchy carbs, giving an advantage to early humans. To put it in simpler terms: carbs were quite important, as shown in our increased ability to digest cooked starch (otherwise, why retain this mutation if we did not rely on cooked starches for a substantial amount of time?). A meat-heavy diet wouldn’t have provided sufficient glucose or energy to the growing brain + 1) large amounts of protein are in fact toxic and 2) providing sufficient amount of animal-based food would require too much effort:

“the energy expenditure required to obtain it may have been far greater than that used for collecting tubers from a reliable source”

Some Context: 

There is no clear agreement on what constituted a “Paleolithic diet”, but it makes sense to assume that our current physiology should be optimized to the kind of diet we had during our evolutionary past. Some important features in our evolution are considered linked particularly to key changes in diet: smaller teeth, smaller digestive tract (1.8 mln years ago), larger brain size (began ~2 mln yrs ago; accelerated around 800,000 yrs ago), and better aerobic capacity (ability of the heart and lungs to get oxygen to the muscles) about 2 mln years ago.

Early hominins include modern humans, extinct human species, and all our immediate ancestors

Some have argued that these changes happened because  humans transitioned from a diet based on fibrous plants to mostly meat-based diets.. But this paper offers evidence that both plant carbohydrates (carbs) and meat were crucial in human evolution. In their words:

We contend that in terms of energy supplied to an increasing large brain, as well as to other glucose-dependent tissues, consumption of increased amounts of starch may have provided a substantial evolutionary advantage to Mid-to-Late Pleistocene omnivorous hominins“.

This photo is missing some starches!

Actual physical remains of early hominins are quite rare, so there is a lot of uncertainty about their lives. As already mentioned, there were several important changes in hominin morphology (size, shape, and structure of an organism) related to the appearance of Homo erectus (teeth, digestive length, brain). Anthropologists propose that they occurred with a change from a “high-volume, low-energy diet” (lots of fibrous plant material that’s not very calorie rich), to a low-volume, high-energy diet (so foods that are more packed with energy like meats and starchy roots & tubers). 

It looks like climate fluctuated between moist and dry periods, which required flexibility in diet (omnivory).. Increased meat consumption has been suggested as an important buffer against such environmental change (and helped expend into new unfamiliar environments), but high starch plant foods might have also been a very common and important part of the diet- especially when cooked. The timing of widespread cooking is not known, but it is argued that it was long enough ago to allow for biological adaptations to take place.

Note: Secure evidence of the use of fire to cook dates to about 400,000 years ago, though some suggestive evidence for a relationship between humans and fire dates to at least 1.6 mln years ago.

The fact that early hominins ate starchy foods is supported by various evidence (the paper goes through rather wordy technical anthropological examples that I fail to summarize in a simpler way). But while meat-eating evidence usually survives (e.g. animal remains with cut marks suggesting being butchered), evidence for plant foods doesn’t, which makes it hard to reconstruct ancestral diets based on physical remains alone (and biases them towards exaggerating meat eating).

Co-evolution of cooking & carb-digesting genes

Humans have the ability to digest starches with the help of enzymes in saliva- salivary amylase! AND humans are quite unusual as we have high levels of these enzymes, suggesting an adaptation to diets rich in cooked carbohydrates. Also, people from populations with high-starch diets have generally more AMY1 copies than those that have traditionally low-starch diets (hey! adaptation!).

Amylase (salivary amylase or AMY1)- enzyme that begins digesting starches in the mouth as it’s present in the saliva. Authors hypothesize that cooking and variation in the salivary amylase gene copy number are correlated.

The variation in copy numbers of salivary amylase genes is an important point of the paper – these enzymes are pretty much ineffective on raw starch, but cooking substantially increases their potential to provide energy/calories. So multiplication of the salivary amylase (AMY1) would become selectively advantageous only when cooking became widespread. (It’s been estimated that the three human AMY1 genes have been evolving separately for less than 1 million years). The authors theorize a gene-culture co-adaptation scenario here: cooking starch-rich plant foods (cultural evolution) coevolved with increased salivary amylase activity in the human lineage (gene evolution). Without cooking, eating starch-rich plant foods probably couldn’t meet the high demands for preformed glucose noted in modern humans.

Note: A mutation that is selectively advantageous means a change in DNA that gives a survival advantage to a particular genotype under certain environmental conditions. SO in an environment where starches are available (e.g. you can find a lot of roots and  tubers) and humans have learned to cook, having more copies of the AMY1 gene that aids in digesting cooked starch would allow those folks to survive more (e.g. in times of food crisis when they can’t hunt or gather other sources of food, etc.) vs. folks who don’t have that mutation.

To further test the paper’s hypothesis, we need “a convergence of information from archeology, genetics, and human physiology”. So let’s stay tuned 🙂


Well, i’m at around 900 words, which is more than the summaries i hope to do in the future! In my defense, this paper was FULL of fantastic information, often rather technical and challenging to explain in less words. I do have some extra content below i found fascinating if you found this summary interesting!

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