Searcher Post in Response to Milk

In response to Manmit's post about milk consumption in America, I thought she really struck home about modern society’s obsession with milk consumption. When I think of my middle school cafeteria I can only picture the walls adorned with “Got Milk?” posters and the faces of famous athletes and stars donning the famous milk ‘stache. Not to mention, milk was the only beverage offered besides water. So what is it with this milk obsession? Is it really as healthy as we think it is?

While milk arguably has its benefits, Mark Bittman persuades otherwise. –-And I think that I may agree. One point that has always stood out to me about the unnaturalness of milk is the lack of milk consumption after infancy in other species besides humans (especially the consumption of milk produced another species.) Not shockingly, 50 million Americans are lactose intolerant, with milk being the second most common food allergy after peanuts. So although many modern humans have developed lactose persistence, many still haven’t. This makes me wonder how the lactose persistence evolution trend will continue.

Dairy is definitely a staple in the American diet but studies prove it may not be a necessary staple. In fact, Vitamin D from good old sunshine and some exercise seem much more responsible for healthy bones than the calcium from fat rich milk. (http://www.nbcnews.com/id/7115733/#.UQtB60pU5hM) Bittman states that there is a correlation between Type I diabetes and prostate cancer, although I could not find any other research supporting this. I do believe that milk was likely a source for not only his heartburn but the acid reflux of many Americans, due to the acidity of milk. From what I can tell, if you like drinking milk, there is no harm. With that said, I also believe that it definitely not as crucial to our health as we have been brainwashed to believe.

Cross-Cultural Lactose Intolerance

As someone who recently made the change from being vegetarian to vegan, I was especially interested in the role of dairy in most modern diets. We discussed the Paleolithic diet this week, and the ways in which our diets have drastically changed since then. One major change is the increased dairy that most people now consume. I used to believe it was natural to eat dairy--I loved cheese, whipped cream, ice cream, and butter. (I never drank milk though--my parents always gave us soy when we were young, and I hated that.) It was only recently that I made the connection that humans really didn't consume much, if any, dairy until the start of agriculture. Learning about the evolution of dairy consumption further convinced me that it is not something that humans need at all to survive.

However, I had not really considered the possibility that some humans can digest dairy much better than others can, until reading chapter five, which delves into the differences in lactase persistence cross-culturally. This article discusses the modern distribution of lactose intolerance in relation to ancestral lactose consumption. It discusses a study of people who do not have lactose intolerance from various parts of the world. The study found that colder, higher-latitude places have populations with the lowest lactose intolerance. Descendants of areas where it was easy to raise cattle tend to be more tolerant of lactose than descendants of areas where dairy was not consumed as much. This implies that the cultural evolution of domesticating cattle sparked biological evolution which now determines which people are more or less tolerant of lactose. In America, for example, 30 to 50 million of us are estimated to be lactose intolerant.

It would be great if more people were aware of the historical norm of lactose intolerance and the fact that humans had to develop tolerance to lactose. While dairy is fine for some populations of the world, it has been proven not to be beneficial to many others, and there is a common misconception, particularly in American culture, that milk is required for strong bones and growth. I've always been looked at funny for not drinking cow's milk, even though this is the historical norm for humans--and what should be the current norm for some populations, according to our textbook and the article that I found.

Introduction Blog

Hi everybody! I just joined this class on Monday after dropping my Social Psychology class. My major is Psychology right now, but I am planning to change it to Math. I also plan on doing a German minor, and I'm Pre-Med so I eventually want to be a doctor. I've always been really passionate about health and medicine, because my family preached to me from a very young age about how important health is. Recently, I've been very interested in nutrition and the healthiest possible way of eating, as shown by history and comparing different cultures and diets around the world. I suppose you could say I'm a bit of a health nut.

Here are three really interesting blogs I found that I think are relevant to this class:

1. Luscious Lipids
http://www.drfranklipman.com/luscious-lipids/#more-13980

2. Breast Cancer Deception: World Medicine
http://www.naturalnews.com/Report_Breast_Cancer_Deception_2.html

3. Exerpt from The Starch Solution
http://www.drmcdougall.com/misc/2012nl/feb/excerpt.htm

The third blog is especially interesting to me--I was directed to it by my grandfather who has been very influential in my interest in health and proper nutrition. This "blog" is actually an excerpt from a book written by Dr. McDougall about his take on what he calls "the real paleolithic diet." He discusses the importance of starchy wholes foods--unrefined grains, vegetables, fruits, potatoes, etc.--in our ancestors' diets as well as our own. He also discusses the difference between the wealthier people who were eating "richer" diets with more animal protein and the people who were eating more grains and plant-based foods, noting that bodies of higher-class humans who ate more like we do today indicated heart diseases just like we're seeing more and more of now. Not only does McDougall look back in history, he also explains different diets across cultures, discussing their starch-based diets and evidence of good health. I also really liked that he dispelled the common belief that starch is something bad that is only really found in potatoes. He provides a handy chart of starches that are classified as grains, legumes, vegetables, and fruits. I've always known what healthy foods look like--whole, plant-based foods. I never thought of starch as the basis for a diet before though, so I found it really interesting to explore this blog. I definitely learned more about what constitutes starch and the importance of it in our diets, something which I really knew nothing about before.

GM Allergy free milk?

According to Wiley’s evolutionary perspective towards cow milk consumption and health, there have been different adaptations to lactose. The ability to break down lactose by the means of lactase has not been a universal adaptation, considering that different populations across the globe do not share the same levels of lactase persistence. 

Since the typical western diet includes large quantities of dairy products in addition to carbs, sugars and fats, the ability to consume milk without discomfort is considered "normal" through the general public, and showing that those who do not share this persistence are instead suffering from a condition such as lactose intolerance which is diagnosed as a disorder.

Interestingly enough, it appears that in order to bring people who suffer from severe lactose intolerance, biotechnology has come to the rescue by experimentation with GMOs and cows to produce “low allergy” milk.  This is being done by adding “extra genetic material to disrupt the manufacturing process [of beta-lactoglobulin protein, a known whey allergen] using a technique called RNA interference” (Gallagher).  Considering there’s much speculation around the usage of GMOs and in this particular experiment, a hormone was used in order to produce a calf from the original cow, “Daisy”, it seems unlikely that it will be a process used in the near future since studies will need to be made on future generations of the modified cattle (if any) as well as making sure that future generations will not contain the existing allergen.

            Changes in agriculture are becoming the norm as biotechnology advances throughout the years and into our very plates, without us even realizing it. Rather than eating foods that the products of domestication have provided for us, humans turn more towards GMOs and additional refinement processes to alter these foods so that they’re more palatable.  Although I’m personally not very fond of GMOs, I think it’s interesting to see to what extent biotechnology goes into trying to better human lives whether it is to produce crops for malnutrition in Africa or to accommodate people in more developed countries. 

First Blog, All about me

Hello all! I added this class two weeks late, so therefore I am late with this introductory post. My name is Jaquta Box, but many people call me Jay. I am a Community Health Major (Health Administration Health planning).  I am taking this class because I decided that one-day I will work for the CDC, or the World Health Organization and I thought this class would give me a little insight on Human Diseases, and evolution. I’ve been interested in medicine since I was 14 years old, and any class that will expand my knowledge about disease, the human body, science, and medicine is for me. I am hoping to expand my knowledge about medicine, evolution, and diseases, not only in America, but in areas all over the world.

List and links to three blogs that are relevant to this class…

Blog #1

Pain and Surgery in the early 1900’s

http://www.wellcome.ac.uk/en/pain/microsite/history3.html

Blog #2

Why alternative medicine is winning out against conventional (Chemical) Medicine

http://www.naturalnews.com/029625_americans_alternative_medicine.html

Blog #3

Antibiotic resistance bacteria

http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Antibiotic_resistant_bacteria

The following blog really caught my attention, and it moved me and I will explain why…

Blog #3

Antibiotic resistance bacteria

http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Antibiotic_resistant_bacteria

This article really touched my heart, and this is one of the reasons why I’m interested in medicine.  Knowing that medicine that we have developed over the years, not being able to work on basic bacterial infections is scary! Before we created all of these drugs via medicine the mass population was dying from bacterial infections such as pneumonia, and a lot of post births infections. Streptococcus pyogenes has been the main cause of death before the creation of antibiotics. Now that more bacteria is becoming resistance to antibiotics, we may start seeing an increased rate in deaths among individuals from a disease that once was easily treated. I wonder if this bacterial disease became resistance to antibiotics, will these bacterial diseases be considered viral? This moved me because I would like to research all forms of diseases, it’s origination, prevention, Tx (Treatment), Dx Diagnosis, and so forth. I do have an understanding of the saying, “The survival of the fittest”. With  this saying in mind, I realize that bacteria is a living thing, and it will continue to evolve, and adapt to its environment just like every species. As bacteria is evolving, and trying to survive, I would like to do the same with the human race. I would like for the human race to adapt and to survive all forms of diseases, and maintain our dominance, and survival on earth. 

This article  make me remember to stay healthy, do proper hand cleaning, and realize that as we as humans adapt, all living things will do the same, or die. 

Guts, Evolution, and The Human Diet

Rob Dunn’s article, “Human Ancestors Were Nearly All Vegetarians”, specifically addresses the evolution of the human digestive system in relation to our diets and resulting health, even going so far as to examine the effect of our ancestral bacteria. The article seeks to determine the “right” Paleolithic diet to follow, similar to Turner’s “search for a true human diet”. While Dunn doesn’t seem to doubt that agriculture has led to a decline in health (p. 65), he challenges this notion, saying that our very simple and historically adaptable digestive system has once again adapted to process processed foods. Although Dunn says to take note of recent ancestors, he fails to mention pre-dispositional health circumstances in relation to the “gut”, but then again, he does make a point to focus on the nutritional value of whatever food is consumed.

We are able to counteract the decline in health with modern medicine and technology – therefore, it seems that we are trying to return to our ancestral diet (or at least the positive results of it) as an act against our current food-related health crises. Not unlike ancient foragers, the only way to do so is by using the resources readily available to us, it’s just that the resources happen to be mass production and unhealthy ­processing. Even on an individual level, we use the resources most readily available to construct our diet – of course, this is why diets vary across persons who reside in particular regions and cultures. This is a subject that comes up often in my own life – my parents are Filipino immigrants; I was born and raised and live in suburban America; and I lived on my own in the London, England for a short amount of time. In my case, diet is mostly consistent with cultural and environmental factors present during childhood or the “home” state. Additionally, this is as influential as the types of resources available -- home-cooked meals in varying portions vs fast food in large portions vs simple food in small portions – but there is only a small amount of outside influence (such as education, wealth, experience, etc.).

For more information, check out this article from The Economist about the “Caveman’s Curse”.

Week One-Searcher

In Chapter 5 of Wiley and Allen's section in Medical Anthropology, they talked about how growth and development are affected by many factors, including environmental conditions. Such adverse environmental conditions that could stunt growth and development include a variety of pollutants and toxins that can mostly be found in places that are "poor, often urban or peri-urban industrial zones near manufacturing plants that make use of toxic substances (p.133, Wiley and Allen)." An example is the relationship between birthweight and air pollution. "Birthweight was negatively related to pollution severity, even after other factors such as socioeconomic status had been controlled for statistically (p.134, Wiley and Allen)." An article that I had found was another example of the effects of the environment, specifically the environment in a person's home, can greatly affect a family's health.

Source ://womennewsnetwork.net/2012/11/05/clean-cookstoves-film/

In underdeveloped countries, the simple act of cooking a meal for your family could be life threatening. Half of the world population today cooks over an open fire, which could pose risks for families being exposed to toxic smoke. This toxic smoke could cause disabling diseases and results in nearly two million deaths yearly. Documentary film director Rodney Rascona is pointing towards solutions of this prevalent problem in underdeveloped countries. In her documentary, she portrays the risks of cooking in an open fire and some of the solutions that we could implement in these countries in solving this problem. Cleaning cookstoves in developing nations could improve the lives of woman and their families significantly. 

What Rascona was trying to accomplish through her documentary was more awareness towards an easily solvable problem in global health. Wood-burning stoves in homes could accumulate toxic fumes that could cause debilitating diseases for families. Rascona traveled to three different continents and documented stories of strong women who have been affected by toxic fumes, as well as how we can easily prevent something like this from happening. This ties in with woman's health and how she can impact the health of her family. Woman are the main caretakers of the family. Her actions could directly affect the health of her children

It all makes sense now.

For Russians, Ivan Turgenev' Fathers and Sons has always been an ultimate account of generation gap, telling a story of young people trying to change the world with radical views and actions. What really important is the ending - the protagonist, dying from a blood infection, finally rejects his nihilism and spends the last days of his life as a loving son.
What this character was primary upset with has been his parent's attention, and specially constant recalls of their youth. As you might see, the phenomenon of parents telling their offsprings truly outstanding tales of the past is nothing new - neither your parents nor your grandparents have invented this kind of torture - it has existed for centuries.
By now, you might be wondering - "If this is old as humanity, is this somehow encoded into our behavioral patterns?"

Luckily for us, not only Connie Svob and Norman Brown, the writers behind Twentysomething, have come up with an idea that humans memorize their early years because of all the important experience they get, but also have actually conducted research. The study compared what people both from peaceful and war-torn nations had heard from their parents. As it turned out, the overwhelming fraction of them has been some sort of important youth memory. Early memories turned out to be, in fact, to be the most commonly remembered thing.

For me, this has been a great insight into the way human body and mind works. Even such a trivial thing as memorization turned out to contribute to procreation and survival. This is a great surprise for me, to say the least. From this, however, comes the question: how many evolution-driven types of behavior or reaction routines are there? Does this mean there may be such thing as evolutionary psychology?

I'd like to hear a peer opinion.

What is the right diet?

I found the section regarding obesity and food choice within Human Evolution, Diet and Nutrition the most engaging. I feel, as if the media could be misleading in most instances. The book sees us “living in a time characterized by soaring rates of obesity, heart disease, hypertension, and diabetes” that has resulted for unhealthy diets in America. The diet that most people seem to be following would be the “westerns” diet that depends on livestock and dairy products. Where growing countries have increasing income also have increasing demands for foods that were limited before. For instance, in the article Global food crisis: The challenge of changing diets they are also speaking of obesity in the US being an issue. They state, "seven out of ten states with the highest poverty show are among the 10 with the highest rates of obesity". I feel growing issue has to do diet choices and not merely as much with genetics. The selection of diet is related to the income of each family group and the affordability of foods.  More so, processed foods are more affordable but carry high in saturated fats, calories and sodium and fresh food are expensive. Thus, the media in industrial countries tend to promote unhealthy fast foods rather than healthy fresh foods leading to the demand in agriculture to decrease within the years to come.

Milk. Milk. Milk.

After reading Allen and Wiley’s Evolutionary Perspective on Cow’s Milk Consumption and Health, I realized that, you know what, I still like milk. So much so, that I “got milk” to write this post.

As a 5’9” North Indian gal, drinking milk has never been a problem for me physically. I was quite intrigued to learn that this was because of an innate predisposition of lactase persistence. Yet, despite coming to understand the science behind the evolution of lactose, I admit to subjectively reading the studies and comparing them with my own experiences. Wiley distinctively defines the weak relationship between milk consumption and growth as in Danish children (Figure 5-2) emphasizing that in more developed countries, little to no effect was created. A stronger correlation was seen when a calcium-deficient population was tested. Maybe it’s my mom’s voice in my head, but “she made me a tall girl by making me drink two milkshake glasses of milk everyday”. And up until now, I believed her. Not only is the relationship flimsy, but, based on a US study conducted (p 124), nonexistent among girls!  Nonetheless, there’s no doubt that in adequate moderation, milk provides many nutritional benefits. To some degree I find the implications of cancer and cow milk overstated, but pertinent to understanding the relative novelty of dairy products as a staple in the human diet. Whether cow, goat, sheep, soy, almond, or coconut, too many bio-cultural factors play a role in the action of chronic diseases.   

                So there must be a more biological reason why not only cow, but dairy consumption has steadily been increasing the past one hundred years or so, right? In my opinion, yes. And, I cannot explain myself without referring to the evolution of the human diet. As surprised as I was to see a whole chapter devoted to cow’s milk, I was more surprised on the short explanation of diet and nutrition provided in the text as it plays a large part of human evolution. But, this idea of adaptive taste preferences and aversions made me take note of the strength of all five senses and how they are capable of widening the “breadth” of foods humans consume. The age of agriculture and domestication introduced an entire new pallet of taste preferences in order to maintain a proper diet. The domestication of animals and the increase in dairy consumption led to stronger bones, particularly the teeth (http://milk.procon.org/view.answers.php?questionID=000977) promoting oral health. However, this revolution forced an irreversible change on the way humans consume food. Before the agricultural revolution, hunters and gatherers often ate hard, thick food which evolutionarily provided them with longer skulls. As food become more cooked and soft, skull and jaw sizes shrunk, more quickly than growing dentition. Ultimately this led, is still leading, to a “rise in occlusal abnormalities and malocclusion” (http://jn.nutrition.org/content/133/11/3893S.full). And, it hasn’t become better; despite an increase in milk consumption and its calcium’s benefit on preventing cavities, teeth decay is at an all-time high. And, oral health is reflective of an individual’s overall health, reiterating the subpar modern diet the modern world has fallen victim too.

                In the end, I still like milk, even though it may not be natural, but it’s just another adaptation humans must evolve to as well as numerous other dietary and nutritional changes.

got milk?

This week’s reading was interesting for me. I've never liked milk – I’d do just about anything to not drink it. My sister loves milk so I would just bribe her to drink mine when my mom wasn't looking. My cereal always had the bare minimum of milk. I dunked my Oreos in the part of ice cream that got liquidy after sitting out for a bit (so delicious!) and washed down my cookies with water. Forget broccoli or brussel sprouts – milk was the biggest enemy during my adolescent years.  

Now it’s a lot easier for me to avoid milk. Not only do I live in an apartment where I get to control my diet (the only time I use milk is when I’m baking or cooking much to my mom’s disappointment), but I have scientific and religious backings also to justify my dislike of me. For a few years now there have been major breakthroughs in research concerning milk. The supposed benefits are really beginning to fade in light of all this new information about the harms of milk. What once was considered a major factor for child growth (my mom still blames my 5’3” height on how I didn't drink enough milk, not on how she’s 4’11”) is now being partially blamed for a variety of things from heart disease to breast cancer (click here for more information).

Although the religious backings might not have weight with a lot of people, keep in mind that religion has had a huge role in shaping society and culture (more information on religion and society here). Napoleon Bonaparte once said, “A society without religion is like a vessel without compass.” Although by no means am I saying that religion does or should play a huge part in society, I’m merely suggesting that it does influence it a bit. That being said, my religion is Jainism. We believe in non-violence and are non-egg eating vegetarians (More information about Jainism can be found here). Although the principals of Jainism state non-violence and we don’t eat eggs or seafood or poultry or anything of the sort, until recently many Jains have not been vegan. Recent findings about the lack of nutrition and health and milk and the conditions in dairy farms (here for information) have caused many Jains to either drastically reduce or completely cut dairy from their lives. Jains aren't the only ones either – veganism is a growing movement in the US and the world with such prominent figures as Bill Clinton, Pamela Anderson, Lea Michele, Alec Baldwin, and Kristen Bell making the switch.

With the lack of solid evidence that milk is more beneficial than harmful and in a society that is becoming so hyperaware and taking action against injustices to not only humans but animals also, my adolescent self can’t help but get excited at the prospect of the milk craze finally fading out. 

A Species Wide Change in Diet

     What I found particularly interesting in this week's readings was the idea that humans are really not that old.  We've essentially gone from being hunter-gatherers to sedentary desk workers is a blink of an eye. Evolution has already caught up with our diets once by making our brains bigger and guts smaller.  What will the next step be?
     Obesity and diabetes have become the new epidemics of our time and are mostly due to our sedentary lifestyles and diets high in fat and carbohydrates. From my experience working in hospitals, it is almost a safe assumption that a given hospital patient is diabetic.  Because these conditions have become such major issues, many fad diets have gained popularity.  People are obsessed with losing weight.  Two recently popular weight-loss methods are hot yoga and Atkins.  Hot yoga is an intense yoga work-out in a 105-degree-Fahrenheit environment, intended to help participants sweat off the weight.  It causes severe dehydration in exchange for the loss of five pounds in one session. Many people who try the Atkins diet, a low-carbohydrate, high-protein weight-loss diet, generally do not understand that excessive amounts of red meat can lead to increased risks of heart disease and cancer.
     People have been fascinated with ancient bones and what they can tell us about the lifestyles of our ancestors.  We know that a lot of Northern Europeans drank milk and developed the ability to digest lactose into their adult years, as opposed to other mammals who lose the ability in late infancy.  On the other hand, most other cultures did not develop this ability, at least to the same extent as Northern Europeans.  Drinking milk is clearly beneficial to bone development and calcium absorption, even if the exact reasons cannot be pinpointed.  While there are milk programs in schools, adults often drink soda instead, which robs their bodies of calcium.  As a whole, humans need to learn to eat healthier and exercise more, because our lifestyles are changing too quickly for nature to fully catch up.

Intro Blog Assignment

This is late. Darn, technology. Belated greetings.

Hello, class! My name is Jose Torio and I am an MCB major. What caught my attention about this class is the name itself: "Evolution and Human Disease." I thought it interesting to learn about health in the context of our environment and our interactions with others, as well as health in the global perspective and factors that contribute to incidence of infectious diseases. Last semester, I took a class about international health policy last semester and was looking for more classes to take that related to my interests in public health, so I thought this class would help me better understand the field in some way. Also, I have intentions of going to medical school. I believe this class will help me become acquainted with the field and how we can apply the anthropological perspective on disease into the field of medicine.

Three blogs that are relevant to this class:

"Lab-Rat" (Scientific American)

http://blogs.scientificamerican.com/lab-rat/

"Busting Myths about Human Nature" (Psychology Today)

http://www.psychologytoday.com/blog/busting-myths-about-human-nature

"John Hawks Weblog"

http://johnhawks.net/weblog

Interesting Blog Post from "Busting Myths about Human Nature":

http://www.psychologytoday.com/blog/busting-myths-about-human-nature/201204/race-is-real-not-in-the-way-many-people-think

While browsing the blogs I saw as interesting, I came across this blog posting that discussed the social construct of race. It explains that there is no biological evidence that could distinguish one human from the other. Race is based on physical differences between groups of people, such as skin color, that define a person to one of these groups who shares the same physical features. There is no biological element that could prove that people are confined to certain groups. In fact, biological evidence shows us that we are more similar than different, as humans share similar genes. Even though there are variations of genes, scientists have found no way to segregate people based on these variations.

The blog also briefly discusses how race can affect our health. Race often defines social structures for particular groups, such as access to health care and racial self-image, can impact how our bodies and immune systems develop. The effects of racism can have many health implications caused by racial inequalities that prevents a person from the same opportunities as other, more privileged racial groups.

Chapter#5: Cow's Milk Consumption and Health

There is this documentary called Forks Over Knives (2011) by Lee Fulkerson, and this documentary was basically based on how people should start eating an all-plant based diet because of the tremendous health benefits. One of the key points in the movie, was to remove milk from peoples diet because studies conducted on rats showed that intake of regular cow’s milk was linked to a higher risk of getting cancer. It also showed how in the Philippines, when milk was starting to be produced, the number of children getting liver cancer or other disease associated with the liver rose to a noticeable amount. The link they believe to cause it was milk since that was the only aspect that changed. Other studies in China also showed the link to milk and a higher risk of getting cancer. The reason why milk was becoming bad to consume was because of the hormones given to the cows. The cows are injected with hormones so they won’t get sick because the diet they are given is bad for them and they were deprived of nutrients for lactating year round. What people were drinking wasn't milk but chemicals.

 There are a lot more interesting claims and evidence in the documentary to back up the claim made, but the moment I read about milk in Chapter 5 and the benefits of growth, hormones on milk, and how some milk was like to diseases, this was the first thing to popup in my head. 

I found this information so profound because in the chapter, Philippines and China was a couple of the places mentioned where milk was linked to better growth, yet in the video they were one of the places with increasing health problems. The sources used in the chapter are older than when the documentary was made, so it is possible that more information is now available on milk. The thing is people are still drinking milk every day if it wasn't for the documentary I saw I wouldn't have known what is really going in the sense of milk and its affects. The information is so different in these to resources, what are people supposed to believe? Why don’t more people know about this? Can all the milk we drink now come back to hurt us? 

Week One - Searcher

Both chapter 5 of Wiley and Allen as well as the blog post “When I was Your Age” spoke of the declining age at which puberty begins. Wiley and Allen’s text attributes this to consumption of higher-energy foods and access to health care (128). While this is probably a large factor in the trend of decreasing age, I have always heard that growth hormones in commercially produced animal products (notably chicken) are, at least to some degree, responsible for this. Further, I have heard that these hormones affect females more than males, furthering the young age at which puberty begins in females.

Joel Fuhrman mentions in his Huffington Post article that there was a decline in the age of puberty from the early Twentieth Century until the 1960s when the trend leveled out. Further, he states that the mid-1990s began to see another decline in the age of the first menarche. Despite this, the two online resources I used remain inconclusive as to the effects of animal hormones as well as the causes of the early onset of puberty. Fuhrman goes on to list multiple potential causes for the decline in menarche age including childhood overweight and obesity, diets providing low nutrition, increasing levels of intake of animal protein, and exposure of endocrine-disturbing chemicals (EDCs) (Fuhrman). An article hosted by Cornell University states that in the US only six steroid hormones are used legally in meat production. Of these, three are naturally produced sex hormones. Further, these steroid hormones are only legally used in cattle and sheep. The article lists two cases of reported effects of animal growth hormones on human consumers, however these remain inconclusive. In one, USDA and independent lab results differed and in the second the meat was not available for testing. The article does state that the amounts of the three non-sex steroid hormones are subject to limits set by the USDA (Gandhi).

While it seems that there has not been conclusive evidence that the levels of hormones currently legally allowed within the United States have major effects on health (including the age of first menarche/onset of puberty), the potential risks of the early onset of puberty, including increased risk of breast and ovarian cancer as well as cardiovascular disease, necessitates further study of the issue (Allen 129, Fuhrman)

Online Sources:

Fuhrman, Joel, M.D. "Girls' Early Puberty: What Causes It, And How To Avoid It." The Huffington Post. N.p., n.d. Web. <http://www.huffingtonpost.com/joel-fuhrman-md/girls-early-puberty_b_857167.html>.

Gandhi, Renu, and Suzanne M. Snedeker. "Consumer Concerns About Hormones in Food." Cornell University. N.p., n.d. Web. <http://envirocancer.cornell.edu/factsheet/diet/fs37.hormones.cfm>.