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. 😉

Healthy Eating- Real or Imaginable??

The lobby of one of the conference hotels during non-busy time. The hallways were overflowing with anthropologists all over the world just hours later 😀

This December I presented on my research at the American Anthropological Association in D.C. (woohoo!) What a blast! The conference was bursting with anthropologists all over the globe; the 5-day event was so packed with presentations that the program which included just names of talks & authors ran about 500 pages.

Anyway, one of the interesting moments from the trip was a scholar (I believe she did some work in Latin America but I don’t know what kind of anthropologist she was), who was seemingly bothered by our session on food and nutrition. Our talks focused on “healthy eating” as a social construct [a social phenomenon created and developed by society; a perception or idea that is ‘constructed’ through cultural or social practice]. My talk was on how perceptions of what healthy eating means differs among and within cultures (Ukrainians & Americans in my study), while other presenters talked about how food is discussed in the Canadian Arctic and among those following a traditional “paleo” diet plan. 

Presenting on my Ukrainian study!

The question this lady asked was why we spoke of healthy eating as something created and perceived by humans as if there is no objective healthy diet supported by science.

It’s a bit funny to hear someone being surprised that concepts are discussed as a social creation vs. an objective reality at an anthropology meeting.. but that shows how food and healthy eating can be quite emotional when one is health conscious! I would bet this scholar was someone who personally cares about eating well for her own health. Understandable. Food is a very emotional topic- it is not only good/bad for health and looks, it also represents our identity, our culture, our experiences, etc.

Part of my answer to her was that science might not be able to give her what she is looking for- the objective healthy diet. Not because science sucks, but because nutrition studies are lengthy, complicated, and costly (see my post on why nutrition science doesn’t suck HERE). My favorite example of why nutrition science is hard to rely on is SUGAR. Look at this World Health Organization 2003 report (see full report).

The common sense might tell you that added sugar can’t be good- it adds calories, maybe it makes you hungrier or disrupts bodily processes, maybe it’s just unnatural. People I interview often mention that sugar is one of the main causes of weight gain. Common sense, right? Well, look at the WHO report and check out Free Sugars (= all monosaccharides and disaccharides added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and fruit juices). The only convincing evidence from scientific studies is that free sugars increase the risk of dental caries. Not weight gain, not diabetes, not heart disease. Does this mean sugar is only bad for teeth? No, it means there isn’t evidence that it causes other disease with the studies that we have. So if you want to state with complete confidence that added sugars lead to chronic disease and obesity, you might have a hard time backing it up.

 who1 who3

Thinking that there is no such thing as a healthy diet is unsettling. We want clarity. :S Saying that “healthy eating” is an idea constructed socially, however, doesn’t mean that there is no such thing as healthy eating. It does mean that there are multiple ways one can eat well to avoid disease- it can be vegetarian, vegan, paleo, regular calorie restricted diet, Mediterranean diet, etc. etc. etc.

Historical perspective on what good/healthy eating is.

The official stance on a healthy diet is not purely unbiased either- the political and historical context shapes what is officially recognized.  I heard a very interesting talk on the differences in nutrition perceptions between Denmark and Germany during 1940-1945 by Dr. Jensen (University of Copenhagen). She talked how in the early 20th century macronutrients, salts, water and ash were believed to be the sole constituents of food.  Then vitamins were discovered resulting in growing scientific interest in identifying new “micronutrients”, a development that altered (diminished) the perceived importance of the macronutrients (protein, fat, carbs).  So as in Denmark micronutrients became the focus, good nutrition became about vegetables- the source of many micronutrients. In Germany, however, a country experiencing hunger during WWII, macronutrients remained as most important considerations in nutrition textbooks (with protein considered the primary element of food- for the satiety and strength it provides, especially for a country at war!). The point is- the scientific (and thus public) perceptions of what good eating means is shaped by societal circumstances.

It all just depends…

Baklava- a middle-eastern dessert I am absolutely insane about. My friends sometimes wonder how I can study health yet eat something so “unhealthy” as a high sugared dessert. IS it unhealthy? Turkish people love their sweets, yet traveling around Turkey will show you that the population is not plagued by obesity and chronic disease.

Back to whether an objective healthy diet exists or not. If we ignore for a second that people disagree on the details of what one should eat to stay healthy (is carb or fat evil? is animal protein toxic? should you go vegan? avoid gluten like the plague?), most folks at the minimum agree that eating “real” or whole foods is important (or in other words- avoiding or limiting modern processed foods and focusing on the less modified foods). I suppose we could say that this definition of a healthy diet is generally accepted. If we move on from processed vs. whole, though, here are a couple of examples of when something generally healthy might not be good for you or vice versa:

Cabbage! A wonderful plant full of micronutrients (vitamin K! Vitamin C!) that protect one from various diseases; the plant is often stated to have anti-inflammatory and anti-cancerous properties. Awesome. Unless you have hypothyroidism since cabbage is one of the foods that interfere with the thyroid function.

Dairy! Gets a lot of bad rep from the paleo community and others. While recently thought as very important for bone health and what not, there is a lot of talk that we have not evolved to tolerate it quite well and it is thus an unhealthy substance to consume. Our genes are still adapted to the pre-agricultural diet (before ~10,000 yrs ago), as many paleo proponents will argue. Yet there is evidence to challenge the assumption that humans are essentially unchanged since the Paleolithic era. E.g. “recent” evolution of lactase persistence and variation in the number of genes that code for amylase production tied to starch consumption. In other words, mutations have occured that allow many folks to digest and thrive on dairy and grains just fine.

– Phytates. Plants have a lot of great ingredients that generally affect us positively (e.g. vitamins protecting from disease), but it depends.. For example, phytates in grains and nuts are usually viewed as bad for us because they can bind to certain dietary minerals leading to deficiencies (iron, zinc, etc.).. In West Africa, many Hausa plants contain substantial amounts of these phytates (especially in cereals and legumes) but these botanical chelators have a potential malaria-suppressive effect (awesome!!). However, this anti-malarial effect may be antagonized by antioxidants in other foods (e.g. such free radical traps as Vitamins C, E, beta carotene, selenium). Antioxidants is something many of us try to increase in the diet..yet if you are living in malaria-prone regions of the African continent, you might want to concentrate on the opposite dietary strategy- phytate-rich and antioxidant-poor foods.

989898So is there an objectively healthy diet? Generally- all eating is healthy since it is required for survival.. undereating and overeating is not good.. lacking a variety nutrients is not good.. and that’s mostly it. Of course, different things work for people- someone might not tolerate dairy, others might feel miserable on a vegan diet; some thrive on salads others can’t digest raw plants well. If only we could all grasp the wonderful concept of moderation and apply it in our lives without struggle. In fact, it is because self-control is so hard to maintain that we want simplified solutions- a diet plan, a list of “bad” foods to simply avoid, etc.

Happy Holidays– don’t overeat on most days, yet don’t let yourself stress so much about what you’re eating that you are unable to enjoy life! 😉 *grabs a big fat piece of dark chocolate and kicks back*.

Microbiome Vs. Human

If an alien came to Earth and randomly took a gene sample from one of us… they would most likely end up with a microbial, not human gene. Humans are outnumbered: we have 10 times more microbial cells and 100 times more microbial genes than our own. (February 2017 correction: apparently, that 10:1 ratio was based on one sample from the 70s… while actually, the ratio is more 1:1, so a human body has equivalent amounts of microbial and own cells 😉 gut

Today I heard a fantastic talk by Dr. Alcock- a practicing physician and a PhD in evolutionary biology (great combination that more health professionals should/will be getting in the future!). The question he and many other researchers are now asking is: can microbioms manipulate us to behave in their favor? Perhaps we are not autonomous in our eating; perhaps some of our behaviors represent another genetic interest.

The talk included a lot if interesting outcomes from animal studies on the subject, but that is material for a longer post ( by somehow who is more qualified than I). I will simply summarize some interesting points:

  • Microbiota and humans are not enemies- it is a marriage of convenience where the interests of one are also beneficial to the other. The bugs in our gut do need us to stay alive, as it is good for them also. However, microbiota might not always act in the best interest of the host as the interests of two might result in conflict. Even small differences in gene relatedness can result in conflict (pregnant mothers and fetus, for example, share 50% of genes). And there is zero relatedness in humans and bugs in our guts.A cool example of a conflict is mice infected by toxoplasmosis- such mice in fact seek out feline urine and are attracted to it (vs. having an innate aversion in non-infected mice); they thus look for cat urine, increasing the chances of being eaten by a cat and the parasite spreads further. Microbes can manipulate behavior in other ways- the cordyceps fungus causes its hosts (ants) to act completely out of “character” and leave their normal ground habitat to move onto the high leaves, helping the parasite disperse more spores [The Last of Us video game probably has you familiar with this fun fungus!]. Lastly, human organisms harbor known pathogens as well, yet they do not cause us harm (e.g. e-coli); it is interesting that these pathogens do not produce virulent factors when given simple carb solution (sugar!), a nutrient they require and would otherwise need to get aggressive for.FullSizeRender (1)
  • We can surely manipulate our microbioms. The diet we eat has a huge effect on who’s in our guts- a bug profile of a vegetarian and meat eater are quite different (see photo above). There appears to be a witch-hunt for the bacteria that might be responsible for obesity in humans, but this search has been unproductive with the same suspects being either related or completely unrelated to weight gain.What seems to matter most is the diversity of the bacteria, not having a certain type of it. A Mediterranean style diet with high fiber, for example, produces a more diverse gut environment, while a fast food diet creates a limited one. Some other determinants of a diverse vs. limited environment are on the slide below.  Key Point: Low diversity= Bad health outcomes. Some non-dietary ways to ensure a healthy diverse gut population are probiotics intake (and decreasing antibiotic use), vaginal birth, and breastfeeding; Babies not born vaginally in fact acquire a less complex microbiota that harbors more pathogens.FullSizeRender
  • Can microbioms manipulate…us?? That is the question. Can the gut bugs make us behave differently? Can they make us eat badly and become overweight? While we shouldn’t assume anything for humans yet, there are some examples of potential mechanisms through which bacteria could have an effect on the host.
    • Bacteria has been shown to produce hormones (some are important in stimulating appetite) and neurotransmitters (e.g. serononin that makes us feel good). We need to ask though- do these things pass from the gut to the brain and are actually successful in influencing us? The human body does fight these hormones and neurotransmitters by producing enzymes and antibodies that degrade them and prevent them from crossing barriers (another mechanisms is encapsulating the gut in fat, which also protects the body from escaped bacteria “signals”). It is interesting to note that the microbes might have evolved the ability to produce these things before humans did (as environmental microbes do this too, not only ones that inhabit us), thus they are not primarily meant to affect us.

In conclusion, what we can take out of this knowledge is that we need to encourage people to have high diversity of bacteria in their gut! A whole food diverse diet is a great way to do so, for example. Should we blame our gut bacteria for making us eat junk? Probably not. We can’t pin the blame for obesity and other chronic conditions on a particular microbe, though an overgrowth of one specific group in the gut might be a conceivable issue with their signals interfering with the bodily signals (e.g. in terms of how to eat via hormones and neurotransmitters).

There is so much more fascinating material to cover on the subject but that is for a later date! Lastly, an interesting question was asked in the audience- obese individuals in fact have a low diversity of bacteria… would unhealthy weight gain then be a bad thing for the microbes? Wouldn’t it be a “win” for the human and loose for the bacteria? Interesting question to test 🙂

All material was obtained by a lecture “Allies or Enemies? Gut micribiota & the war on fat” by Dr. Joe Alcock, MD. 2014.

Health- The New Religion

I despise healthism… which is strange for an ex-health nut who managed a health food co-operative and taught raw vegan cooking classes for several years. Let me tell you why the importance of being healthy in the modern age can be quite irritating and perhaps even…unhealthy.

What is healthism?

Healthism is the modern trend towards promoting personal responsibility for health, placing an increasing focus on individuals to create the perfect healthy body. Healthism represents virtuous living as a moral accomplishment and this trend has taken on some of the religious attitudes toward foods (e.g. the moral sin of gluttony).

Sounds like taking responsibility for your  health is a wonderful thing. Indeed, it is quite beneficial to “take care” of yourself by trying to eat nutritious foods, stay active, continuously educate yourself on the health consequences of various choices…. because the modern environment has made the “normal” lifestyle quite problematic (sedentary behavior, cheap junk food, and what not).

Screen Shot 2014-02-09 at 5.22.21 PM

The problem, in my opinion, is the fact that these personal decisions have increasingly become morally-laden decisions. It’s evident that the “health religion” is spreading through the fact that people make moral judgements about others’ worth based on what and how they eat (there is a number of studies showing that people view strangers who eat “healthily” as more virtuous, less likely to cheat, less lazy, and what not). Of course, moral judgments also are applied to the physical manifestations of presupposed internal qualities for those who are overweight (e.g. lack of self-control, greed).

On the other hand, our culture encourages the enjoyment of food- at parties, special occasions, when socializing.. You’re not “fun” if you’re too strict with yourself (surveys also show people perceive those who eat healthier (while more moral) as less interesting and nice to be around socially).

*** Photo on the right- Not only does it imply that your health is completely your responsibility (which is a bit of a privileged view, you might say, since not everyone has the opportunities to eat organic or exercise) but it is your moral responsibility to the whooole world.***

Continue reading

“New Perspectives on Vegetarian Diets” (Health Conference)

Today was the second day of the healthy lifestyles conference organized by Arizona State University and I was very much impressed by the vegetarian speaker! Actually, I know the professor, Carol Johnston, since I am involved with her vegetarian study..but this is the first time I heard her talk on the subject.Image

I was particularly impressed with the way she discussed limitations of vegetarian studies that many people do not consider (and many vegetarian researchers do not necessarily point out)-

  • The studies usually have many confounders (generally vegetarians studied tend to be more lean, educated, physically active, supplementation, no smoking/drinking, etc).. So a lot of their characteristics have nothing to do with meat avoidance but an overall healthy lifestyle
  • Studies showing fantastically superior health of vegetarians do so due to comparing vegetarians to national averages (which are not so great).  When vegetarians are compared to meat-eating groups who also follow healthy lifestyles, the difference in health is not as prominent.

Some important things to consider with vegetarian and vegan diets is B12 and Vitamin D (also zinc, calcium), since these populations do tend to be low in these vitamins. Dr. Johnston herself raised her two kids omnivorous, since she has concerned with a number of studies showing dangers of low B12 in small children. Indeed, during pregnancy one’s B12 decreases as well.

Some of the well-accepted benefits of vegetarian lifestyle are lower risk for colon and breast cancer.

Of course, Dr. J discussed the ecological piece and the importance of diminishing one’s intake of animal calories for those reasons.Image

Vegetarian for all??

I found it fascinating that once an audience member asked a question about recommending vegetarian diets to lower SES communities, Dr. J answered that she understands we have evolved on meat and we were meant to eat it, but in this day and age with disease, environmental issues, and low animal product quality (+ horrible animal treatment) vegetarian diets in her view are a better solution (but one might need to be a grown person to adopt it). She would not recommend going vegetarian in the 3rd world countries.

I loved the last comment, because my observation has been that people try very hard to prove our ancestral diet was vegan. It seems to be not so, but I don’t believe this fact is a reason against vegetarianism. I think Dr. Johnston’s view is very rational- you do not have to sell the vegetarian diet as the most original and natural for our species (it is not as evidenced by deficiencies due to animal product avoidance), you simply need to concentrate on the fact that this diet might be much better for you personal health, for the environment, and the animals.

P.S. Dr. Johnston also has fascinating research on vinegar and it’s beneficial effect on type 2 diabetes management and weight loss (just google Carol Johnston vinegar diabetes)

Meeting Mr. Paleo!

Is there anything more exciting than a health conference???

Well, there is always chocolate, but the conference excitement is quite comparable.

ImageArizona State University has organized a great conference “Nutrition for Optimal Health and Performance”.  Today’s lecture included speakers on athletic nutrition, debate on the High-Fructose Corn Syrup, and Paleolithic Nutrition.  Right now I shall focus on the Paleo presentation.

S. Boyd Eaton, MD from Emory University is considered the “father” of the modern paleo movement (you would know him from the Paleolithic Prescription book). He himself considers himself the “grandfather” since much of his original ideas have been somewhat transformed by other (younger) researchers (and he does not necessarily agree with all).

The Hypothesis

The presentation was not new to me, since I have read several of his papers.  In short, Dr. Eaton talked about the basis for the paleo health idea- the “discordance hypothesis“, according to which our genes and our lives are discordant (we adapted to a certain food and activity pattern, which is not matched by the modern sedentary/processed foods lifestyle)… The mismatch of the current obesogenic environment and our stone age genes are the reason we suffer from “western” diseases.  The human of 40,000 to 15,000 years ago is fundamentally identical to the modern human.Screen Shot 2013-02-08 at 8.35.37 PM

Then Dr. E talked about different % of meat subsistence of recent hunter gatherers which ranges from 20% animal products to 95%.  They/anthropologists take the 50% of animal protein in the diet  as the model due to the idea that most of us come from the savanna region of Africa (with 50% animal dietary intake).

He also discussed that anthropologists have rather good ways of studying old diets (human skeletal remains, archeological finds, recent hunter-gatherers, and proximate nutrient analyses).

The “Ancestral” Diet

The Paleo-Nutrition of East Africa (~50,000 years ago) is considered to be comprised of 35%, 25-35% protein, and ~35% carbohydrates. Of course the carbs, protein, and fat of long ago and the present day are not the same (obviously, less processed and more micronutrient rich; the fat was more polyunsaturated, more long chain PUFA, and less cholesterol-raising fat).  Other noted differences – vitamins and minerals were 2-8 times higher than average American intake; much higher potassioum-to-sodium ratio, the diet was more basic than modern acidic diets, and much more antioxidants than at present (generally 4x). Dr. E especially emphasized fiber- vegetables in the wild are much more fibrous.  Lastly, the energy intake was considerably higher, but caloric density was low (there was more bulk- more fiber, more water in food). Dr. E also talked about “free water intake”- most of the fluids consumed were part of the vegetables&fruits.

That’s all great, but here is something that was new to me. Dr. E himself differentiated between the “weak” and “strong” forms of the paleo prescription. It’s hard to say what all forms of “paleo” people out there are following, but my impression is that folks try to stay pretty strict with what they believe our “ancestors” ate. For a healthy normal individual, however, Dr. E’s weak form consisted of-


The strong form (which seems to be the popular form as I can tell from talking to folks) is for people with “resistant health problems or who are unable to maintain desirable biomarkers” + competitive athletes.  This diet is what you would usually recognize as “the paleo diet”completely excludes grains, dairy, and alcohol.

The AfterLecture

The most exciting part for me was listening to Dr. E talk to a group of people after the presentation. A dietitian asked about the lack of legumes and beans in the paleo diet (she was upset about such nutrition advise). He commented that this was not something he necessarily agreed with at all, and that this idea originated with a different researcher (sorry, I can not remember who).  My friend asked how he viewed a paleolithic diet without meat (she is mostly vegetarian).  He said his understanding of meat avoidance is very much justified on ethical and moral grounds, considering the treatment of animals and their health (thus, the healthiness of their meat).  And if one could get their protein adequately from other sources that was great too. So he was not particularly married to one type of the ultimate human diet. Overall, Dr. E was a pleasure to be around.

My Comments on Meat Avoidance

Another dietetics student, who I know is a vegan since we are both involved in a vegetarian study, asked how he would respond to the massive literature on the health benefits of vegetarian diets and the problem of saturated fat from meat. Dr. E “politely disagreed” that vegetarianism was necessary for health but did not elaborate as much as we hoped. I understand the doc does not view being vegetarian as necessarily more healthy (considering you could do paleo with grass-fed free range meat and all). But I also wish he could talk about this further.Screen Shot 2013-02-08 at 8.29.54 PM

As someone who was vegan for 2 years and is very familiar with various health rationales for avoiding animal products, I have come to the conclusion that it is not necessary to exclude these products from the diet for health. Many cite The China Study by T. Colin Campbell, which is a book I also used to refer to (in brief, it shows the connection between animal protein and cancer). However, after looking into people who eat “traditional” diets (e.g. the Weston A. Price foundation diet), and seeing the vibrant health they enjoy… I had to come to the conclusion that all is not as black & white as I expected. In regards to meat & cancer, I am fascinated by new information on mTOR. Since I plan to post about mTOR in depth later, I will only say that it is a pathway that can be up-regulated if excess protein levels are detected in the body…in turn this stimulates cellular proliferation and adverse mitochondrial effects. In short- too much protein= increased risk of cancer. But note here that animal protein only in excess leads to adverse health effects, not animal protein per se. Supposedly, 45-60 g of protein per day for the majority of adults is a good amount* for longevity and avoidance of disease.

It was a pleasure to actually talk to the originator of the “paleo” movement, who himself is very balanced and rational in contrast to how the idea can be taken to extremes by many different people. The one thing Dr. E said is that obviously it is not sustainable for everyone to eat a paleo style diet any more, unless we decreased the world’s population drastically. Obviously, that is a different talk altogether.

*Gedgaudas CNS, CNT, Nora T. (2011-05-27). Primal Body, Primal Mind: Beyond the Paleo Diet for Total Health and a Longer Life (p. 196). Inner Traditions Bear & Company. Kindle Edition.

What makes us FULL? (macronutrient perspective)

Sometime in the semester, I heard people speak about satiety (satiation is the process of feeling full & terminating food ingestion during the course of eating) in relation to protein and fat (protein apparently is more satiating, even though fat has more calories).  Feeling of fullness is important- it is one of the problems I faced as a raw vegan, which made sticking to the lifestyle very hard long-term (I was raw vegan for ~2 years).

So instead of preparing for class tomorrow, I am reading up on satiety! Some main points:

Most importantly- it’s not all about the calories, since not all calories are treated equally by the body.  The hierarchy of fullness is the following: Protein > Carbs > Fats. So, protein satiates more than carbohydrates, and fat is least satiating (which came as a surprise to me considering it has most calories per weight). High-fat foods have a weak effect on satiation.


Within the macronutrient categories, we find differences too: not all carbs exert the same effect on satiety (fiber has been consistently shown to have a higher satiety value vs. simple sugars), and neither does fat (the medium-chain triglycerites [e.g. the wonderful coconut oil] seem to be more satiating).

Of course, people don’t eat only to get full. The number 1 reason given for eating a certain food is taste. More specifically- palatability (subjective pleasantness of food). Low-energy-dense foods tend to be less palatable, but more satiating :/

According to the article*, ideally our diet would consist of low-energy-dense foods with high palatability (unfortunately such foods are not very common). This “diet” is one low in fat, has adequate protein and fiber, and includes lots of fruits, vegetables (so food with high water content).

Of course, focusing on whole foods vs. processed makes lots & lots of sense- a whole food product takes time to chew and digests longer (satiety signals are maintained for longer).

Apart from specific studies, common sense must prevail: staying away from “fat” is not necessary (not as much as staying away from processed fat, vegetable oils, etc…), and adding great fats (e.g. avocado!) to meals is both healthy and filling (studies show that while fat on its own is least satiating, it’s power to fill us up increases when it is added to carbs).

Feeling full is important! Constantly feeling deprived could potentially lead to overeatingand more stress.

P.S. I shall probably post more on the subject of satiety later, considering I have a whole class coming up on this topic 😀

*Gerstein, D. E., Woodward-Lopez, G., Evans, A. E., Kelsey, K., & Drewnowski, A. (2004). Clarifying concepts about macronutrients’ effects on satiation and satiety. Journal of the American Dietetic Association, 104(7), 1151–3. doi:10.1016/j.jada.2004.04.027

“Listen to your body”?

Could your body “tell” you what to eat due to its health state? If you’re deficient in a certain nutrient…will you instinctively crave foods with that nutrient?

Many believers in the “body wisdom” would say yes. Actually, i think the idea of body wisdom is extremely popular- I myself know this from the raw diet, and I am sure many alternative “natural” diets talk about this concept (e.g. intuitive eating?). Unknown

I think it is fascinating- that’s why I was excited to talk about this in my psychology of eating class. I tried to find a relevant peer-reviewed article for class discussion, but to my surprise found nothing. In class I understood why- there is no evidence for body wisdom in the literature. There originally was an idea that our bodies can tell what we are deficient in and gravitate towards foods with those nutrients- first rat studies seemed to prove that.  They had rats on a thiamine deficient diet choose between two new diets- one with thiamine, or the previous thiamine deficient one. The rats chose the thiamine diet. They could tell they needed vitamin B1, right? Not really- turns out the rats avoided the same thiamine-deficient diet not because they could sense the deficiency, but due to the learning that the original diet made them somehow sick.  Animals, thus, avoid eating whatever doesn’t make them feel good. They, like we, learn to eat what makes us feel good. The only thing you can have a specific hunger for (so you’d be able to choose food with that particular nutrient in it) is salt- it is easy to taste/identify and we have a genetically preprogrammed specific hunger to it.

Generalist vs. specialist?

When you think about it, animals seem to KNOW what to eat, what’s good for them (I hear people argue we have that ability too, or “body wisdom”). But let’s think about it…an animal that specializes in one kind of food (e.g. carnivore, insectivore) has a very narrow range of foods..they must get all essential elements from those foods= the identification of food can be programmed genetically into them. But for a species that eats anything(or “generalist” animals)e.g. humans– the problem of finding food can be less demanding since there are many potential sources..and eating a nutritionally balanced diet can be achieved in many ways. Perhaps that’s why our body wisdom is not as acute- we are not dealing with a narrow range of foods. (See Paul Rozin for more)


I don’t know whether specific body wisdom really exists- the one that can signal you to eat a certain food because of a B vitamin you’re low on. Either way, I think we have access to a different kind of wisdom- choosing whole unprocessed foods is much closer to our evolved physiology than any of the new created foods that seem to be destroying our health. Apple vs. apple juice- that seems wise 😀

Eat healthy for healthy kids!

Looks like a varied healthy diet is important before a kid is even able to eat solid foods. Specifically, it is important for pregnant and breastfeeding mothers, since a child’s first experiences of flavor occurs prior to birth through milk feeding and amniotic fluid in utero.

SO eating a variety of vegetables and fruits influences acceptance of these foods at the weaning stage (~5.7 months).

Breastfeeding is crucial (vs. formula-feeding), since it prepares kids for novel flavors through the mother’s diet being transmitted to milk [Flavors so far known to be transmitted through breast milk are garlic, ethanol, carrot, mint, blue cheese, and cigarettes]. If formula-feeding is the only option, it is important to switch formula flavors and types to allow for variety.

Conclusion: varied diet in pregnancy and during breastfeeding is recommended.  Some suggest that up to 6 month is the period we are most sensitive at for introduction of different flavours..and that we are never again as open to new experiences!*

Note: repeated exposure to one flavor can become monotonous and actually decrease liking in a child.. so that would be counterproductive (again, variety is good!).


Being overweight or having a “junk” diet (for mothers) can be potentially detrimental for kids.

1. Being overweight/obese is a risk.. The problem- overeating and obesity during pregnancy lead to in utero overnutrition..and can cause the development of obesity in the adult offspring (even when the child had normal feeding and lactation).

During pregnancy leptin resistance and hyperphagia occur, which lead to increased deposition of fat.. In lean individuals this is a great adaptation allowing mothers to store energy in preparation for lactation (a high metabolic demand activity).. But in the current “obesogenic” environment this adaptation would make it hard for women to regulate their food intake (especially those predisposed to obesity).**

2. While I haven’t found a study on humans, studies on rats show that rats born to mothers fed junk food during gestation & lactation developed an increased preference for sugary, fatty, and salty foods; they also exhibited increased weight and BMI. Data from numerous studies shows that maternal junk food diet can change the ofsprings’ epigenetic marks related with long-term changes in gene expression (opiods & dopamine) and behavior (stronger preferences for palatable foods- sugar/fat/salt).***

* Article doi:10.1016/j.appet.2011.05.317

** Article doi: 10.1210/en.2008-1106

*** Article doi:10.1210/en.2010-050