First encyclopedia chapter published!

Woohoo!

My first encyclopedia chapter is finally published!

I was researching and writing this one while traveling across 3 countries this summer and collecting data, so the whole process was not necessarily a piece of cake. Thus, i’m extra pumped this is finally available! If you want to read the chapter but can’t access it, feel free to email me and i’ll send you the PDF 🙂 -> mvoytyuk (at) asu.edu

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NOTE: It’s actually highly ironic for me to write on how cooking could have been instrumental in the evolution of our large brains- I spent 2 years as a highly motivated raw vegan! Indeed, I took several “raw cooking” and educational courses in different parts of the U.S. (Illinois, California), was a private raw “chef”, and taught raw veganism workshops for over a year at a food co-op I managed.

This chapter doesn’t actually comment on whether there could be health benefits to eating a diet higher in uncooked foods. It does focus on highlighting the fact that we appear to be particularly adapted to cooking. So, I’d say it does not support a 100% raw vegan diet as a worthy endeavor.

Click HERE for the encyclopedia page, and here is the short intro:

The disproportionately big human brain is a conundrum – it is larger than would be expected for a primate of our size, and it is a very energetically expensive organ. Since human basal metabolic rate (BMR) is not elevated to match such a big brain, the extra energy needed to sustain it suggests a dietary explanation. Feeding the large brain would likely require a shift to a high-quality diet: one comprised of energy-rich, easily digestible foods. This hypothesis is supported by a number of anatomical features: smaller teeth, jaws, stomachs, and a shorter large intestine. Two key elements of human subsistence – cooking and meat eating – have been proposed as a possible means of achieving this high-quality diet.

Evolutionary Medicine in action!

I went to a great talk at ASU’s Evolution & Medicine center, where Dr. Stearns from Yale University discussed tradeoffs 🙌🎓. I’d love to invest the rest of this day into summarizing what i’ve learned but i’ve got a dissertation to write, jobs to apply to, etc. etc… So a really short science communication bit is all i can manage!

Short version: Look at this chart.. It shows how mental illness is a result of a conflict between paternal and maternal genes. Notice how autism and szchisophrenia manifest most at the extremes of a newborn’s birth weight.

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Long version:  “Imprinted brain theory” argues that maternal & paternal set of genes might have antagonistic reproductive interests: father “turns off” genes that down-regulate fetal growth, resulting in enhanced growth. Mother turns on these genes, inhibiting growth.. Both actions result in normal range of weight of the newborn.

The mother is 50% related to each of her offspring.

The logic behind conflicting interests from the parents is such: since a father is uncertain that a woman’s other and future children will be his, it may be in the father’s reproductive interest for his child to use mother’s resources MORE, while the mother’s interest (considering she’ll be 50% related to all her current and future children equally) is to limit this and have resources for future kids. With polygamous mating, offspring’s genes from the father will be selected to extract MORE from the mother, and maternal genes will be selected to resist such increased extraction of bodily resources.

To simplify: father needs current baby to use up as much of mother’s resources to grow bigger/stronger/have higher chance of future reproductive success because he can’t be sure her other kids will actually be his.

A conflict arises when action of one parent is cancelled by disrupting imprinting- so disruption of maternal interests would result in an uninhibited expression of paternal interests. Such disruptions result in abnormally low or high birth weight (along with other factors such as behavioral aspects- the extremes of which are considered mental illnesses). Extreme genomic imprinting in favor of MATERAL genes will result in lower birth weight, and is argued to cause psychosis (schizophrenia spectrum) while the opposite causing autism spectrum disorders. The chart above shows how such abnormalities in weight are indeed associated with autism & schizophrenia.

Red meat, human vulnerability, and.. mammal pets?

12993520_545709718944195_6669954929821747069_nExciting day! Another diet-related talk at ASU’s Center for Evolution & Medicine. This was a nice break from the horror that is the last 2 weeks of the semester..

It’s taking me awhile to “digest” all the information (hehe), but I found the seminar fascinating and wanted to summarize some main points. Lots of open questions remain, but John Pepper of National Cancer Institute really shows how examination of any health problem needs to focus not only on proximate causes, but the ultimate or evolutionary causes.

So.. Pepper asks- why is mammal meat bad for humans, specifically?

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Meet Dr. Pepper!
In humans, red meat (he refers to it just as mammal meat) is linked to inflammatory diseases (cardiovascular, alzheimer’s, arthritis). What’s the mechanism behind this?
The inflammation from mammal meat has to do with our antibodies attacking something coming from other species.. When we eat mammal meat, we in fact incorporate something non-human from the diet- sialic acid.
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Both human and other mammals have sialic acid in their tissues, actually, but humans have a unique mutation that replaces the form found in other mammals (ancestral form- Neu5Gc) with a different one- uniquely human (Neu5Ac).
So.. if we eat meat we get the new aquired ancestral sialic acid, it becomes part of our cells, and the small structural differences in the two get recognized by the immune system.. which responds with a defense- inflammation!
Chimpanzees are humans’ closest evolutionary relatives, sharing a common ancestor 6–7 million years ago..
WHY does human sialic acid differ uniquely? The “Malaria hypothesis” (see Martin&Rayner, 2005) proposes that in Africa, early humans escaped from the ancestral pathogen they shared with chimpanzees. They managed to do so by replacing the pathogen’s binding target (ancestral sialic acid Neu5Gc) with novel Neu5Ac. With time, a population of that old evaded pathogen evolved to infect humans again by recognizing the new Neu5Ac..leading to the origin of malaria.
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The longer an animal has been domesticated, the more humans share parasites and diseases with them

If the Malaria Hypothesis explains why the initial change in humans happened.. why has it remained the same to this day? I mean, it’s been some several million years now- has this mutation been advantageous this whole time? It’s an important question because this sialic acid mutation poses a COST on our health: this trait causes chronic inflammation in people who eat mammal-derived foods + it also now causes vulnerability to malaria.

The hypothesis for why the human sialic acid modification is still around is that it
provides benefits- specifically, protection from parasites and pathogens via increased inflammation. This is relevant because of what humans have been doing for the last ~15,000 years. Animal domestication!
Humans are more vulnerable to shared pathogens from other mammals (than from non-mammals). So being around cattle, for example, carries a risk of catching pathogens from which that cattle suffers. Such animal pathogens impose a strong selective pressures on humans.. Pepper suggests that the uniquely human sialic acid (Neu5Ac) allows our diet to adapt us to the issue of animal pathogens by adjusting our inflammatory tone (how much inflammation we are experiencing): “those human populations that are exposed to domesticated food-mammals and their pathogens are also eating mammal-derived foods that are pro-inflammatory (both meat and dairy).”
Inflammation is a great example of a trade-off. It both has benefits (protection from parasites & infections) and costs (chronic disease, metabolic expense of mounting an immune response). The optimal balance for this trade-off would depend on how strong of a pathogen pressure you’re experiencing.
This increases inflammatory PROTECTION only where it’s most needed (like around animals). So this auto-immune inflammation from mammal foods in the diet not only increases likelihood of chronic disease, but protects against shared mammalian pathogens.
…..    ……    ……
It got me thinking about human culture and our ability to modify our environment in all sorts of ways- an example of “maladaptation” to modern times! Living in cities, not exposed to higher pathogen load from being around domesticated animals..yet having access to all the mammal meat we can buy = all put you in a situation where the good old sialic acid mutation might do more harm than good. Should people go vegan? Should they simply cut down on red meat? There was no discussion on the effect size of mammal meat eating and chronic disease, so I wouldn’t necessarily jump onto any lifestyle changes based on this talk. Yet the process of understanding this health concern through the lens of evolutionary medicine is quite fascinating!
 P.S. I’m not an expert on this topic. If you have something to correct or add, please comment 🙂
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Very cool use of evolutionary medicine principles in this case & a glimpse into why it’s important to use them if we want to understand disease.

 

Eat Less- Live Long? Not so FAST..

Got it- to FAST? 😀
The past week has been a treat in terms of great talks on campus. At ASU we are super-lucky to have the Center for Evolution & Medicine, which holds weekly talks by amazing speakers.

First
February 18- Arizona State University

When I saw that the upcoming seminar was related to diet and eating..or more specifically NOT eating or “dietary restriction”, I of course RSVPd in a heartbeat.

“Eat breakfast yourself, share dinner with a friend, give the supper to your enemy”- Russian Proverb

I’ve been in fact fascinated with caloric restriction for years now Screen Shot 2016-02-20 at 1.30.46 PM.png(I wrote a whole research paper on it in the first year of my master’s degree). You might have heard of intermittent fasting (e.g. popular in the CrossFit world), or the CR Society ( http://www.crsociety.org/ )- all are related to the concept that restricting food intake results in health benefits (from extending life to preventing and reversing disease).

I’m sure you can Google caloric restriction and find a bunch of information on its reported benefits..you would see this chart at the CR society website- the lifespan of calorie-restricted (CR) mice vs non-CR mice. You can see that those whose food intake was restricted by more & more % lived longer. Screen Shot 2016-02-20 at 1.24.28 PM.pngWhy do many animals (and perhaps humans) appear to be so well-adapted to eating less? The traditional interpretation of this CR phenomenon is that the dietary restriction effect “has evolved as a way to enhance survival & preserve reproduction during periods of naturally occurring food shortage”. In other words- being adapted to do well on restricted food intake during rough times would have helped our ancestors survive them & stay healthy to have kids later when the food situation improves.

The traditional interpretation of this CR phenomenon is that the dietary restriction effect “has evolved as a way to enhance survival & preserve reproduction during periods of naturally occurring food shortage”.

Experimental evidence with animals, however…supports a different hypothesis- the one Dr. Austad (Professor & Chair of the Department of Biology at the University of Alabama) presented to us last week. Again, I wouldn’t be able to cover everything he discussed during the seminar, but I do want to highlight a couple of main points!

I. First, even though the first book on dietary restriction (DR) HowWorks.jpgdates back to the late 16th century, we still do not know the mechanism behind why DR seems to extend life and vigor in animals + delay disease such as cancers. METABOLISM was the original suspect, as metabolic rate goes down with fasting.. however, metabolic rate drops initially yet gradually goes back UP (takes 6-8 weeks to happen).. Since DR changes an unbelievable amount of physiological parameters (see screenshot ->) it is very hard to determine its mechanism.

II. Second, while many sources cite mice experiments showing life extension with caloric restriction.. those experiments are done with lab mice. When DR studies are done with wild mice, DR has no effect on longevity. WHAAAT!! I’ve never heard this before- in fact i was under the impression that CR/DR extends life in animals, period. Well, NO STUDY has ever found that DR extends life or improves health in nature (or even “nature-like” conditions). Mice in the wild actually do not have enough fat stores to reduce feeding except very briefly (wild mice has about 4% fat while a regular lab mice has 15%; also lab mice do not reproduce). In fact, mice in nature simply do not live long enough for the survival benefits of DR to be important. Another challenge to the original hypothesis that adaptation to dietary restriction enhances survival, is that DR increases mortality from some infections. Lastly, DR increases cold sensitivity (and cold is a major source of death in wild mice) and slows down wound healing.

Sounds like animals in the wild would not benefit from adaptation to dietary restriction… yet why is the positive DR effect observed in so many studies so common?

III. Well, even though wild mice do not live longer with restricted diets, DR still results in cancer protection for them. But even more importantly, DR has been found to protect against acute effects of many many toxins! Dr. Austad talks about this discovery in the following way:

 .. if animals can not afford to wait to reproduce..and they have to do it even when food conditions are poor, what they will do is broaden their diet. This means they might be ingesting a lot of toxins they are not normally exposed to (foods infected with fungi, new seed types that are well defended by the chemicals they wouldn’t normally encounter). So the hypothesis is that DR acutely induces broad defense mechanisms from a broad range of toxins

Toxicology studies have shown that mice that are calorically restricted survive a wide range of toxins. DR also acts as an acute (vs. chronic) protectant against other problems (see slide below). Renal ischaemia reperfusion injury (IRI) is a common cause of acute kidney injury and we can see that while ad libitum mice are dying steeply by day 7, those on DR of various proportions survive (30% DR is only 70% of normal food intake; ad libitum stands for eating as much as one wants). This is quite impressive!!!

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These acute benefits of DR have very important implications. We can think about these effects actually protecting the body against the toxins it itself produces (like free radicals).. it also has clinically relevant advantages- e.g. patients on very strong drug cocktails fasting to avoid harsh side-effects. This suggests that the protective effects of DR could have clinical relevance unrelated to chronic benefits like life extension.

The new hypothesis explaining the evolutionary advantage of this paradoxical effect is that dietary restriction arose as a defense against novel exposure to toxins during food shortage.

So in conclusion.. we saw evidence suggesting that dietary restriction would NOT enhance survival in nature. Yet research has shown that DR increases health and life in a diversity of species. The new hypothesis explaining the evolutionary advantage of this paradoxical effect is that dietary restriction arose as a defense against novel exposure to toxins during food shortage.

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My conclusion? I’m still excited about this topic- more than ever before!!! There is a lot of work done now on the timing of food intake as well (not just restricting the amount, but restricting the timing of eating and human health) and I can’t wait to post more about this (after I collect some necessary data though :).  Watch out for early May as I’ll be sharing some more info!

Meat, Plants, and Humans..

This week on ASU campus I managed to attend a fascinating talk: Reconsidering the Role of Plant Foods in Hominin Diets by Dr. Chelsea Leonard. Screen Shot 2016-02-17 at 11.41.44 AM

It was a job talk for the Evolutionary Anthropology department here at ASU and Dr. Leonard is an evolutionary ecologist interested in “human foraging decisions & diet reconstruction”(so- her work would help to clarify what humans ate in the past!) working with Twe populations in Namibia (southwest Africa).

Why does Dr. Leonard study the role of plants? Since shifting towards more meat in diets of early humans has been suggested to be crucial for the unique adaptations in our genus (e.g. large brains), animal foods appear to be very Screen Shot 2016-02-17 at 12.00.04 PMimportant. There is indeed a strong case for meat in a human diet- in comparison to chimpanzees who are mostly herbivorous (eat plants), the human gut has opposite proportions- our small intestine is much longer, while the colon is a lot shorter. The colon is where fiber fermentation occurs- something crucial if you are eating lots of plant foods (and wild plant foods are very high fiber!). What Dr. Leonard suggests, though, is that meat’s importance in human diets may be quite overstated (especially in meat-heavy “paleo” diets popular now).

The people she studies- Twe- are “forager-horticulturalists”; while the Namibian government has been providing maize for them (this started very recently, in the last 7 yrs or so), they mostly forage for wild foods and have very low intake of animal products. Apparently, historically this population hunted large game and had a higher meat intake.. but the area is very poor in large animals now (and has been this way for ~200 yrs).

While I wont’ be able to describe everything Dr. Leonard discussed, I found the following fascinating.. Based on her observations and interviews with the Twe, she constructed and analyzed a hypothetical (yet realistic) diet for this region. Since Twe seem to be doing just fine health-wise with an extremely low animal food intake (there might be some birds, insects, rodents eaten from time to time), she wanted to test if their meatless diet truly meet basic nutritional requirements. FullSizeRender 9

Based on the plants the Twe regularly eat, her analysis showed that such meatless diet can realistically provide enough protein (it can reach minimum levels of essential amino acids our body can not produce without foods that contain them), it can also provide enough fat (while most plant sources were extremely low in fat, the grass seeds often eaten are rather high in it). The main issue with this meatless diet was calories. Getting enough calories to survive would be improbable : while the hypothetical food intake reaches 1774 calories a day.. only 772 of them are metabolized. What this means is that a lot of these calories are not available to the human body- since humans can not ferment fibers very efficiently, a lot of this rough wild plant fiber is indigestible and does not provide our body with energy.

The main issue with this meatless diet was calories.

Since foraging for wild plants  is very labor intensive (and this does not really mean standing around picking berries, but e.g. digging up roots that are about 1 meter (~40 inches) into the ground, or grinding grass seeds and cooking them into porridge), there isn’t enough time in a day to get enough digestible calories from foraging. So animal products are more efficient and provide a concentrated mix of not only essential nutrients, but fat, protein, and calories. While the speaker couldn’t quite estimate the % of calories coming from small game (the birds, insects, etc.), it was very small but still was a part of this population’s diet [note: any time honey was available, it was eaten in large amounts and rather adored, apparently!]. Thus, while a  vegetarian diet can be maintained in our modern world with plentiful food supply (and supplementation), it was not possible for non-industrialized populations.

humans are highly adaptable as we span huge geographical areas, and thus no single “diet” “made us human”

We know humans are highly adaptable as we span huge geographical areas, and thus no single “diet” “made us human” (thus, there is no one Paleo Diet). Yet plants are extremely important in our history- we see that they can sustain populations in good health to a very large degree. One issue with studying the role of plants in human diets is that they do not last well archeologically (e.g. it’s much easier to find evidence of large game being consumed, because their remains last well).

while a  vegetarian diet can be maintained in our modern world with plentiful food supply (and supplementation), it was not possible for non-industrialized populations.

Overall, this was a really great talk! It also reminded me of a paper I read on the significance of plant foods in human evolution, which I talked about HERE.

[note: if you are an evolutionary anthropologist sand have any edits/clarifications to my post, please comment! I am not an evolutionary anthropologist :)]

No need for RAW (food) stress ;)

Most of my present acquaintances are unaware that I used to be a huge proponent of raw foodism. “Huge” meaning I spent hundreds (thousands, actually) of $$ traveling to get certified as a chef and an educator (centers in Chicago, Atlanta, and northern California), taught “cooking” classes at the local co-op, was a private chef for months, etc.

In fact, check out some of the raw vegan dishes I used to make!

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Is this amazing or what? I’m still quite proud of my raw culinary past. The recipes used soaked nuts, dried fruits, sprouted items (like buckwheat) and of course lots of vegetables and fruits. While fun & unique, it was also very time-consuming, rather expensive, and not necessarily healthier. It did fit well with people who have allergies (since raw recipes don’t use soy, wheat, peanuts or many other problematic foods).

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I almost spend all day writing down why exactly I have concluded raw veganism is unnecessary and based on false beliefs… But that would be a true waste of time (and rather dull to me) so I’d rather redirect you to already well-written articles!

False belief 1: We are meant to be plant-based because our physiology shows we’re herbivores! 

  • NO. (my previous blog post). And it’s a good reminder not to attempt to compare our diet to that of other animals and insects (insects! people make the point that insects and animals don’t cook food! insects & animals also can’t perform surgery or produce toilet paper)
  • Another thing worth mentioning is the incorrect assumption that vegetarian/vegan folks are healthier than others because they avoid meat. Majority of big studies I went through in my nutritional epidemiology class compared meat-avoiders with people on a standard american diet…and didn’t do a good job controlling for the fact that they compared health-conscious vegetarians with generally regular unhealthy folks. Luckily i don’t have to write more, because THIS ARTICLE did it for me AND gave citations (woohoo!). Pay attention that health benefits of meat-eaters is more correctly attributed to other healthy behaviors (avoiding refined sugar and grains, oils and trans fats, avoiding smoking and so on).

False belief 2: Cooking is unnatural.

  • First of all, let me point out that some types of cooking of some foods produce potentially carcinogenic compounds. HERE is my post on acrylamides. Like with other valuable claims from raw foodists- this is not supposed to mean you should never eat baked potatoes. It means having antioxidants in your diet from other plants is very important. The new genetically modified potato, by the way is designed to decrease acrylamide content. Unfortunately, generalized anti-GMO sentiments might win over that benefit. 
  • How Cooking Made Us Human Read this wonderful New York times article on the Catching Fire book and how cooking was instrumental in our evolution! I remember I was aghast when i heard of this book- you mean turning food into murderous evil toxic stuff that kills cute kittens made us human?? I’m clearly joking here, but not actually over-exaggerating too much. Many of us in the raw community would absolutely avoid the healthiest of soups, since cooked was equivalent to “toxic” and “addictive” in our heads.
  • Humans are adapted to controlling fire & using it to cook.  See part of the  “Human adaptation to the control of fire” paper here (click on pics to enlarge). For full paper, here is the citation but it might not be free unless you have university affiliation- Wrangham, R., & Carmody, R. (2010). Human adaptation to the control of fire.Evolutionary Anthropology: Issues, News, and Reviews, 19(5), 187-199. TRY HERE.

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  • Here is a fun piece of “fake information” online. I have to address this…Screen Shot 2015-01-30 at 6.36.44 PM

    Author states:
    “Fire was only discovered a relatively short time ago”

  • No- fire was controlled prior to emergence of homo sapiens. In fact, the earliest convincing evidence of fire use for cooking appears the 780,000-400,000 years ago.
  • Animals show that anatomy can adapt very quickly to a change in diet. With human populations that have a history of dairying (like northern Europe), ability to digest lactose into adulthood has evolved at least twice in the last 7000 years. For people with a recent history of eating starch-rich foods, they exhibit higher copy numbers of the gene encoding for a certain enzyme.

    Author states:
    “Out of the millions of species of animals and insects on the Earth, only people intentionally eat cooked food”
  • *cricket sounds*……….. What is this supposed to argue? There is no way to discredit a completely illogical statement.

    Real point here: humans are adapted to cooked diets. Reductions in masticatory and gastrointestinal anatomy show that. See Wrangham article cited earlier. 

 


 

3. False belief 3: We need to eat an all-alkaline diet (or high raw plant diet)Alkaline

First of all, just to clarify: your body can’t actually get “acidic”  (see photo & citation*) though dietary acidosis is a thing. Acidosis is a proces s or trend toward acidaemia ( blood pH of less than 7.35) but without necessarily reaching a pH of less than 7·35″. **  Increasing fruit and vegetable intake, reducing processed junk and not making your diet heavy on meat is a great recommendation to avoid the trend towards acidaemia, though it’s unclear it actually benefits bone and kidney health:

“Both dietary interventions (lowering protein and increasing fruit and vegetable consumption) and nutritional supplementation (with K and Mg salts) have been shown to normalise acidosis, but with discordant results on whether this is then associated with clinical improvement in bone, muscle or other physiological or pathophysiological conditions. A positive NEAP [net acid load] diet results in increased urine Ca, N and bone marker excretion, and predisposes to kidney stones. Whether or not, over the longer term, this translates to lower bone density, increased bone and muscle loss with ageing is unclear and requires further investigation.”**

This does not necessitate eating a raw vegan diet though– it necessitates being reasonable and, like recommended by parents, governments, and nutritionists, make sure to eat your fruits & vegetables and minimize high-caloric processed foods. This also doesn’t mean eliminating animal foods at all. Here is a great article*** that estimates the “acid load” of diets of hunter-gatherers (HG) and modern diets. They find the HG diets were neutral (e.g. not “too acidic”, if you prefer) and contribute elevated diet acidity of modern diets to processed cereal grains. Great idea to minimize on processed products anyway!

aciddd

 *Deng, G., & Cassileth, B. (2013). Complementary or alternative medicine in cancer care [mdash] myths and realities. Nature Reviews Clinical Oncology,10(11), 656-664.

** Pizzorno, J., Frassetto, L. A., & Katzinger, J. (2010). Diet-induced acidosis: is it real and clinically relevant?. British journal of nutrition, 103(08), 1185-1194.

*** Sebastian, A., Frassetto, L. A., Sellmeyer, D. E., Merriam, R. L., & Morris, R. C. (2002). Estimation of the net acid load of the diet of ancestral preagricultural Homo sapiens and their hominid ancestors. The American journal of clinical nutrition, 76(6), 1308-1316.


 

4. False belief 4: Raw Food is superior because it has all the enzymes intact

  • There’s no scientific support for this, and that’s about it. **** In fact, this was my turning point in adhering to this lifestyle: I realized this very foundational claim has no basis.
    The evidence raw proponents cite is a 1985 book called Enzyme Nutrition. That’s 30 years ago… good science is self-replicating so I would expect there to be more studies on such a potentially fascinating subject if there is something to it.. I don’t see any.

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**** Hobbs, S. H. (2005). Attitudes, practices, and beliefs of individuals consuming a raw foods diet. Explore: The Journal of Science and Healing, 1(4), 272-277.

CONCLUSION!

None of this is supposed to go against the fact that eating a lot of fresh fruits and vegetables is very important and very healthy! HERE is a nice Scientific American article giving examples when some vegetables are better and worse when cooked.

But this is supposed to discourage you from forming a belief system that humans aren’t “supposed” to eat cooked and animal-based food***** or that there is a need to stick to eating raw plants only. It is also supposed to prevent damaging thinking- e.g. a hot chicken soup is toxic; cooked food is addictive; non-organic food is dangerous. Humans have a tendency towards monotonic thinking- it’s hard for us to be OK with the fact that something we consider “bad” is only bad at high doses and is actually  essential and beneficial at lower doses (e.g. fat, salt in the diet for some people). Considering this lifestyle takes a lot of time and effort, does not necessarily results in weight-loss (and when it does- it’s just because you eat less calories, not because raw food is magical.. if you go heavy on the nuts & oils you will gain wait), and there is absolutely no reason to consider this eating natural or superior I believe this dietary approach is unnecessary and attempting to stick to a highly raw food diet results in a lot of stress for no reason.

 


 


EXTRAS

Note:I  am intrigued by the possibility that this approach might have therapeutic benefits. It’s not based on any present science, folks, but I would be excited to see studies of this eating plan as a medicinal diet for improvement of certain conditions!!

You are welcome to comment on the blog and ask questions or challenge some of the statements! I’m not anti-raw as much as I am pro-science and evidence. I’d love to research very specific topics so please comment with a specific concern 🙂
***** As a good friend of mine noted- it’s important to remember that vegetarianism/veganism is not only a choice to be healthy..but it’s also a choice due to environmental and ethical concerns. I’m unqualified to cover those in detail, but it is obviously an important reason some people avoid animal products and I’m not arguing against it!
p.s. Links to all sorts of websites debunking some raw food ideas or talking about its shortcomings, etc. Just stuff that came up after 2 minutes of Googling 😉
http://www.veganhealth.org/articles/cooking
http://www.takepart.com/article/2013/05/08/jane-says-raw-foodism-raw-deal
http://www.mindbodygreen.com/0-13454/3-reasons-no-one-should-be-on-a-raw-foods-diet.html
http://www.hellawella.com/top-10-annoyingly-stubborn-nutrition-myths-debunked/9645
http://www.fredericpatenaude.com/blog/?p=2036
http://www.sciencebasedmedicine.org/simply-raw-making-overcooked-claims-about-raw-food-diets/
http://news.sciencemag.org/evolution/2012/10/raw-food-not-enough-feed-big-brains
http://www.huffingtonpost.com/david-katz-md/raw-food-diet_b_2015598.html
http://renegadehealth.com/blog/deathofraw
http://www.beyondveg.com/tu-j-l/raw-cooked/raw-cooked-1b.shtml

Evolution Wants us Happy & Disease-Free… Not

Since I’m part of a reading group on evolutionary medicine this semester (I am no expert of evolution OR medicine, but love to learn from experts!), I wanted to post some cool things I’m learning 😀

[NOTE: To learn more about the topic with in-depth explanations & fascinating examples, please see EVOLUTION AND THE ORIGINS OF DISEASE.]

One fascinating topic is why we humans are susceptible to disease. If natural selection*** shapes successful traits, then why do we catch and develop so many diseases??

Evolutionary medicine is the field that tries to figure out why natural selection has left us so susceptible to illness (physical and mental). Here are some ways to explain our vulnerability to getting sick:

  • Reproduction vs. Health 4111624-heartbreaking (1)

    I feel it is a common misconception that evolution wants us to live longer healthier lives (e.g. when people say that we’ve evolved to eat a certain way that allows us to live long and be disease-free).. and it is disturbing and heartbreaking for some to find out that evolution pretty much doesn’t care about your happiness, health, or longevity. 😦 Natural selection does not shape organisms to increase all those things, it shapes them to improve our fitness (Fitness NOT meaning long healthy lives [and with a six pack, preferably], but having more healthy children). So a trait that actually harms health will still get inherited if it increases reproduction!

    One example I have heard of is having attractive female proportions (waist to hip ratio and all): it increases the chances that you will have more children blaby making a female desirable by men, but it is associated with higher risk of some diseases in old age.Another interesting example is higher mortality of males in adulthood- natural selection can favor such traits as risk taking, (which is important in attracting females as males compete for female attention), though it can decrease the lifespan of people whose personalities allow for increased risk taking.

    I’ve seen that some paleo diet followers discuss evolution as a benevolent force that has figured out a way for humans to live long and prosper, and while that’s not true on the level of the individual (it technically “cares” that the species prospers by spreading), it doesn’t mean that you can’t use evolutionary theory to personally get healthier.

  • Our genes don’t match the environment!

    Humans have created quite amazing conditions for ourselves- sanitation, roads, safe desktop jobs, public transit,  etc.ven Things that make life comfortable and pleasant. And technologically advanced societies see higher rates of various disorders- autoimmune disease, obesity, drug abuse and so on. Many versions of certain genes are only problematic in modern environments. Proponents of all sorts of paleo-related diets, for example, claim our evolved preference for sugar and salt is dangerous in the world where processed foods are cheap and omnipresent (though adaptive in the wild as sugary ripe fruit are nutrient & calorie-rich). Another example is nearsightedness–  it’s a problem in societies where kids begin reading early and is not a problem in populations that hunt & gather.

Other explanations are:

  • Pathogens simply evolve faster than their hosts (ourselves) so we will never have an immune system that is not vulnerable to some disease.
  • There are also tradeoffs: a certain trait can have great benefit in one way, yet it may have negative effect in other respects (again- being a seductive mess on a motorcycle might make females go crazy over you & want to reproduce, but it also makes one susceptible to dying from unsafe choices).

Once again, here is a GREAT read on EVOLUTION AND THE ORIGINS OF DISEASE by Dr. Nesse (MY INSTRUCTOR!) and Dr. Williams with MUCH more comprehensive explanations AND more interesting examples than I have in this blog entry. 😉

KEY POINTS:

  1. Evolution: change in genetic makeup of a population over generations; it requires genetic variation. The variation in genes arises from mutations and recombination. 
  2. Natural selection favors traits that allow an organism to produce more offspring [that is healthy enough to produce its own]
  3. Fitness does not mean personal health & longevity. Fitness means how good you are at leaving a successful offspring. 
  4. Inclusive Fitness: unlike previously thought, evolution doesn’t work on the level of groups/species but on the level of individuals (so traits that aren’t “good” for the whole species but are good for this individual having more kids are going to be selected for). E.g. genes that make one aggressive to others will still pass on if it leads to this individual reproducing successfully.
    HOWEVER, nice helpful personality traits are successful & are passed on (humans are incredibly altruistic vs. other animals) as it makes one do nice things for close relatives. Since you share genetic material (50% with each parent and siblings, 25% with cousins), the individual’s reproductive success actually includes not only how many healthy kids you produce, but how many your closest relatives do also!
  5. There are no traits/genes that are awesome universally. The benefit of a certain trait is always in the context of the environment. E.g. sodium retention is prevalent in people that evolved around the equator since it gave them a selective advantage (salt is necessary to your body but is lost via sweat and urine.. you’d sweat way more in the hot climates).

[***Natural selection: imagine a group of people/dolphins/bugs. If this group’s members differ in some way that influences the likelihood that they’ll be part of the group in the future, this group will end up changing with time. So if some members have a genetic variation that influences how many kids they’ll have, in time this group will change and have more of the genetic trait that resulted in more kids! moth

A popular example is trees that once had light barks but got covered in black soot. The group of moths that used to hang out by the tree had variation in color- some white, some black.. The white ones will end up being eaten up by birds simply because they are now super visible on the dark bark and, in time, majority of moths will be black (the group has changed!) . Thus, a genetic trait is only “successful” in a context of an environment. There is nothing beneficial to being a black moth other than you’re less visible on black bark and thus will end up having more offspring than the white moths in the group.]

No, we are not carnivores. But we’re no apes either.

I often read on vegan health groups that humans are not meant to eat meat because our guts are long like those of the apes (who are predominantly plant-eating) vs. the short guts of carnivores (meat-eating animals). In fact, I used to argue this way myself in my vegan days. 🙂

However, once you understand a topic a bit better, the simplified and incorrect statements about it simply irritate you.

WHAT OUR GUTS SAY ABOUT US..

Human guts, when compared to those of existing apes, have similarities AND differences. Humans and apes show the same gut anatomy- simple acid stomach, a small intestine, etc.. However, humans stand apart from all apes: more than half of human gut volume is found in the small intestine while all apes have by far the greatest total gut volume in the colon; also the overall size of the human gut in relation to body size is small in comparison to that of apes.

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What this means is that humans have adapted to a “high quality” diet. Here high quality means a calorie and nutritionally DENSE diet, which includes animal foods and tubers. A high quality diet for humans means that we need to eat a smaller volume of food to obtain the nutrients and energy we need.

The way our gut differs from apes says a lot. Most large primates have expanded colons, which is an adaptation to fibrous low-quality diets [“low-quality” here = highly fibrous foods such as leaves and bark]. The large colon allows fermentation of low-quality plant fibers (which allows extraction of additional energy in the form of volatile fatty acids). Our relatively enlarged small intestine (the principal site of nutrient digestion & absorption) and smaller colon reflects an adaptation to an easily digested diet that is nutrient-rich.

There is a general consensus that current hominoids (apes and humans) come from a strongly plant-eating ancestry. Apes, however, evolved into larger bodies that allowed to sustain themselves on lower quality diets. By eating both animal matter [to satisfy requirements for essential nutrients] and plant sources [primarily for energy] humans were able to avoid the constraints imposed by body size increases in apes (such as lower mobility and sociality in apes). Simply speaking: the bulkier they get and the more time they spend eating, the less they move around and the less social they are, which is a disadvantage compared to humans.uuuu2

MMM… BRAINS

This dietary change in humans (adding animal and other dense foods), which departed from known plant-dominated diets of the apes, was eventually reflected in our brain size (much larger), overall form of our guts (shift in gut proportions, overall gut size) as well as dentition (smaller teeth, jaws). Concerning our particularly large brains: our brains are particularly energetically “expensive” as we expend a larger proportion of our daily energy on brain metabolism than other primates (in comparison to other primates, our brains are 3 times the size). Paleontologists believe that fast brain evolution happened about 1.8 mln. years ago and was associated with important changes in diet and foraging behavior (some argue it is specifically the addition of meat that allowed for such large brains to evolve). Apart from switching to high quality nutrition, humans show other adaptations to having a larger brain- compared to other primates we are “undermuscled” (less skeletal muscle) and fattier. Greater level of body fatness in human infants in fact helps grow a large brain by having stored energy and reducing energy requirements of the rest of the body (that has less muscle mass).

THUS…

The point is: no, we’re definitely not “meant” to be vegetarian. Also, the point is not to say that vegetarianism doesn’t make sense for many of us. There are plenty of great reasons to avoid animal foods (ethics, environment, etc.), plus it’s easy to have an adequate veg. diet for adults with availability of supplements (vegan diets are not recommended for small children, though, considering brain development; the several vegan PhDs I know did not raise their children vegan specifically because of this) … but stating that we are not meant to thrive on both animal and plant sources is incorrect. Contrasting us with true carnivores [like cats] to show how very different we are (e.g. hey we don’t have claws and sharp teeth… um.. we however do have large brains to allow for sophisticated tool creation that replaces those) is also a terrible idea- we are not true carnivores either and have a dual dietary strategy [plants + animal sources].

Lastly, all this material should not support the notion that we ought to eat bacon 10 times a day.. meat clearly has a place in our diet, but this shouldn’t be used to justify a purposeful meat overload (I’m not sure what the benefit is for advocating heavily animal-based diets, considering modern animals are fattier and less packed with phytochemicals than the wild ones + there’s the whole issue of antibiotic and hormone use at the minimum. Unless, of course, you go on the “carbs are evil” side, but I am not in favor of that view… or you imagine our ancestors ate predominantly meat, which does not look to be the case since the diets varied dramatically depending on environmental circumstances). 

(Note: I’m not pretending to actually be an expert on any of these topics; I simply read peer-reviewed articles and hang out with evolutionary anthropologists 🙂 ).

References: 

Milton, K. (2003). The critical role played by animal source foods in human (Homo) evolution. The Journal of nutrition, 133(11), 3886S-3892S.

Leonard, W. R., Snodgrass, J. J., & Robertson, M. L. (2007). Effects of brain evolution on human nutrition and metabolism. Annu. Rev. Nutr., 27, 311-327.

P.S. The bottom line is: these t-shirt designs are both incredibly dumb (disclaimer- i laughed a bit..but immediately felt guilty :D)

veggg 0000

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.

Evolution made you a misanthrope :)

Well that’s a strange title.. but let me explain 😉

Evolution of Immunity

Evolutionary approach to studying human behavior is focused on the adaptive value of the behavior… so we are asking questions like “why has X behavior evolved and what costs and benefits it brings?” When our sensory system (vision, smell…) is faced with a disease-connoting cues (e.g. a sick person), two defensive systems get activated:

The immune system
The behavioral immune system

Mounting an immune response in the body is quite costly in terms of energy spent and it is required only after the body has contacted pathogens.. but the behavioral immune system activates our basic emotions (fear, disgust) and behaviors that prevent contact with potentially dangerous objects (in terms of transmitting disease), so saving our body precious energy needed for the actual physiological immune response 😉

This behavioral immune system is trying to be over-careful, though, and will react not only to actual disease-reminding stimuli, but also to stimuli that resembles signs of disease (but may not logically be dangerous- like a sterilized glass that used to have a roach in it… there glass is perfectly clean but people are still disgusted when drinking from it… or a person with a disability- they’re not actually contagious).

So, first of all, what does this have to do with being a misanthrope?

Well, this emotional response to things that are dangerous to health (whether truly or only perceived..) is stronger in people who think themselves vulnerable to disease. Such people show a HIGHER level of an averse response to:

  • physically disabled people (Park et al. 2003)*
  • older adults (Duncan&Schaller, 2009)
  • Immigrants (Faulkner etal. 2004)
  • obese people (Park, Schaller & Crandall, 2007)
  • some animals (Prokop et al. 2010)
I know these are not roaches..just chocolate (which i adore), yet i can’t imagine even touching these without disgust

Being open to new experiences and being an extrovert is associated with larger social networks (having more friends&acquaintances), but ALSO with higher risk of being infected by pathogens (the more folks you get in contact to, the more changes to catch something). Again, a stronger negative response is seen in those that perceive themselves to be more vulnerable or come from areas with high pathogenic load (=lots of diseases). So if you’re not a people person, there’s nothing particularly “abnormal” about you.. Indeed, you are quite a well-adapted fellow 😀

And second- what does this have to do with food??

Usually everything I post has something to do with health and diet.. so I need to make a connection here. Researchers hypothesized that, similarly to the behavioral avoidance of disfigured people triggered by this over-protective emotional immunity, new technologies might activate behavioral avoidance. New technology like genetic modification or highly processed foods in general.

Researchers decided to see if they can predict attitudes toward GMOs by people with different levels of pathogen sensitivity. And they did find that people who felt themselves more vulnerable to infectious diseases had significantly more negative attitudes toward GM products (Prokop et al., 2013). Of course, there are many many reasons people do not like GMOs- rational and emotional, but this is a pretty cool finding nevertheless.

So, many things about us and our personality might be an important adaptive response.. does not mean we can not override these “instincts” with some logic (e.g. knowing obese individuals are not in any way going to make you sick thus not stigmatizing them).

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