Saturday, March 10, 2012

The Libertarian Endgame

On September 12, 2011, during CNN’s GOP Tea Party express debates, Wolf Blitzer posed a hypothetical question to Republican candidate Ron Paul, asking who should foot the bill for a healthy 30-year-old man who chooses not to buy health insurance and then suddenly ends up in a coma with expensive medical bills? Paul responded that freedom is about taking risks and personal responsibility, and it is not about the government taking care of everybody. Paul is a libertarian and, as such, believes that government should be as small as absolutely possible and only interfere in people’s lives for basic protection from hostile enemies and criminals.

Blitzer then asked, should we just let him die? Some in the audience cheered, “Yes, let him die!”  Many left leaning groups and individuals used this as a glaring example of the hypocrisy of the right. Republicans are a party that claims higher moral ground, conservative family values, and pro-life agendas, and yet at a party debate some verbalized support for a person dying because he couldn’t cover medical bills.

Paul himself said that we shouldn’t let him die, but he offered only altruistic church groups and charities as the solution. In 2012, medical expenses account for 60% of American bankruptcies.  So, leaving this incredible financial burden for church groups and charities to shoulder means that, in reality, many people would die.

The day after the debate, news broke that Paul’s close friend and 2008 campaign manager, Kent Snyder, died of pneumonia at age 49 after accruing more than $400,000 in medical bills. Paul and his staff raised $50,000 towards the bills, but the hospital bill was never paid off. Apparently, libertarians think it is acceptable for the hospital to eat that bill. So they overlook an important point about our medical system: we pay these bills by a back-door financial policy. Hospitals make up for this kind of unpaid bill by the raising the cost of everyone else’s medical care.

This issue is a defining moment for the US because one could easily blame the high costs of healthcare on the Emergency Medical and Treatment and Active Labor Act (EMTALA), which says hospitals that receive taxpayer money cannot refuse care to people. Would libertarians propose getting rid of the EMTALA? Is this the kind of society we want to live in?

One other reason why healthcare costs are high is that the US political system allows corporations to get so powerful that they can steer government policy towards their own interests. Using their monetary influence, they can break down regulation and fix the game in their favor. If, as libertarians believe, government should be small and only used in defense and the like, who will be there to regulate these big corporations when they are in total control? Their default answer is the invisible hand of the market. But even Adam Smith, the great hero of capitalism, extolled the benefits of the invisible hand only when there is a general well being among all citizens. 

I agree that when it comes to government intrusion on lives of its citizens, I think we should look at policies with a libertarian eye and not make a policy without a good reason. However, there is very good reason to provide health care, both for moral reasons, like those above, but also economic ones. The libertarian stance claims that when government gets involved, costs go up. Ron Paul frequently makes this argument in his speeches. I am not sure where their evidence comes from. Data shows instead that healthcare costs are lower in single-payer health systems.

When the ethical and practical reasons for a libertarian position on healthcare crumble, why continue to cling to the hard line?

Friday, March 02, 2012

Social Determinants of Health: is Psychosocial Stress the Primary Determinant and what are the Implications for the Field of Epidemiology?

The evidence linking social factors to health outcomes has been researched since the 1940s (Krieger, 2001). The so-called social determinants of health has generated its own field of research called social epidemiology. The whole field hinges on social constructs or structural hierarchies embedded in human societies that heavily affect health. Psychosocial stress is one such risk factor that has been identified as an explanation for how social factors influence health outcomes. One of the big debates in public health is centered on competing theories of causation for the social determinants of health. This paper is an analysis of what the argument between psychosocial theorists and the neo-materialists says about the future of epidemiology.

One of the largest studies to garner support for the psychosocial risk factor is a case-control study by Rosengren et al. (2004). This large, multicentre study found an association between psychosocial stress and acute myocardial infarction (AMI). The researchers operationalized psychosocial stress by asking questions about eight variables: stress at work, stress at home, general stress, financial stress, stressful life events, locus of control, feeling depressed, and clinical depression. They concluded that the effects of psychosocial stress were independent of lifestyle factors such as socioeconomic status, smoking, and education and that “the size of the effect was less than that for smoking but comparable with hypertension and abdominal obesity”(p. 961).

The three dominant models of causation for the social determinants of health are neo-materialism, psychosocial theories, and the effect modification hypothesis (Jayasinghe, 2011; Marmot and Wilkinson 2001)
The neo-materialists posit that the root cause is the structure of society and the political system, and that the key to solving this problem is through development—providing material needs to people. The psychosocial theory is closer to the biomedical model in that it argues that there is a direct effect on the body’s immune system through the impact of stress from the environment, and that leads to higher rates of mortality. The effect modification hypothesis positions stress as a “risk regulator” (Marmot and Wilkinson 2001). This means that people in low-income groups have higher levels of stress, which in turn causes those people to make poor lifestyle choices, such as smoking tobacco or consuming excessive amounts of alcohol, and thus have poor health outcomes (Lynch et al., 1997).

The heated debate between these differing camps of causal models is both political and methodological in nature. The neo-materialists posit that the major factor is one’s materials or assets and that having a home, car, and computer are proxies for a higher quality of life. Research has confirmed that once one’s basic needs are met, there are significant health improvements(Macleod, et al., 2001; Lynch et al., 1997). Neo-materialists derive a large part of their evidence from studies on the ecological level, which makes it difficult to generalize to individuals. They also argue that the material level is more amenable to change than psychosocial stress, saying that reducing stress throughout the population is difficult if not impossible (Marmot and Wilkinson 2001).

The psychosocial theorists contend that people’s health is more than their material circumstances and, moreover, that understanding the exact physiological mechanisms of action provides a clearer picture of the disease process(Marmot and Wilkinson 2001). The psychosocial variable has proven to be a highly stable measure, albeit sometimes a subjective one. One of the major points of contention is that humans cannot be randomized to treatment groups; therefore we cannot truly ascertain causation because we have to resort to animal models to experiment on. This type of research brings us closer to understanding causal mechanisms, but because humans and primates are vastly different—despite being 98% genetically similar—we cannot fully accept evidence from those studies. However, there has been compelling evidence in primate models that shows conclusively that social hierarchies lead directly to higher levels of stress in those species. Many psychosocial theorists have measured stress objectively with biomarkers such as cortisol and glucocorticoids, which lead directly to atherosclerotic plaque build up, a major risk factor for cardiovascular disease (Sapolsky, 2005). Another argument made by the psychosocial theorists is that social hierarchies embedded within a country mask the neo-materialist’s hypothesis and demonstrate that key components of the psychosocial variable, autonomy and social capital, are the important building blocks to good psychosocial health(Marmot and Wilkinson 2001).

The effect modification hypothesis has strong evidence linking low socioeconomic status (SES) with poor behavioural choices, and some studies have shown that people of low SES are less likely to change their behaviour (Lynch et al,1997). This means that people in low SES groups have higher levels of stress and, due to their low income, cannot afford higher quality foods and health care, which in turn negatively affects their health. Many argue that this blames the individual and is the least productive of all theories(Lynch et al,1997). The criticism here is not so much about methodology as it is about the politically unsavory way it analyzes people.

From a reductionist point of view, the psychosocial theorists have a stronger argument than the neo-materialists because newer technological advances create the possibility that as time advances our abilities to measure will get better and better. According to the hierarchy of evidence, ecological studies are lower ranking, and psychosocial studies command a higher level of evidence. But because it is so difficult to reduce the social determinants of health into neat categories such as education or SES, there is a call from some contemporary epidemiologists for a paradigm shift away from such reductionist searches for causation.(Jayasinghe, 2011; Krieger 1994; Glass and McAtee 2006) Although reductionism works well in identifying strong infectious agents, it is ill-equipped to handle many complex systems like the social determinants of health(Jayasinghe, 2011; Glass and McAtee 2006)

This debate about causation is a digression from the real issue, which is to find workable solutions to issues raised by the social determinants of health. Epidemiology is in a state of transition or stagnation, depending on whether you view the glass as half empty or full. Many epidemiologists seem content to push an outdated model that can’t address many of today’s problems(Jayasinghe, 2011; Krieger 1994; Glass and McAtee 2006) To refocus on problem solving means moving epidemiology from a field distracted by concern with causation and controlling for bias and shifting it instead towards following Kreiger’s assertion that whatever the means of causation, be it direct or indirect, intervening on social determinants such as education and early childhood development should be a high priority in addressing health outcomes (1996).


1.Krieger, N. Theories for social epidemiology in the 21 century: an ecosocial perspective. International Journal of Epidemiology. (2001);30:668-677.
2.Rosengren, A., Hawken, S., Yusuf, S. et al. Association of Psychosocial Risk Factors with Risk of Acute Myocardial Infarction in 11,119 Cases and 13,648 Controls from 52 Countries (the INTERHEART study): Case-control study. Lancet. (2004);364:953-962.
3.Jayasinghe, S. Conceptualising population health: from mechanistic thinking to complexity science [electronic article]. Emerging themes in Epidemiology. (2011). 8:2
4.Marmot, M., Wilkinson, R.G. Psychosocial and material pathways in the relation between income and health: a response to Lynch et al. British Medical Journal. (2001);322:1233-1236.
5.Lynch, J.W., Kaplan, G.A., Salonen, J.T. Why poor people behave poorly? Variation in adult health behaviours and psychosocial characteristics by stages of the socioeconomic life course. Social Science and Medicine. (1997); 44(6):809-819.
6.Macleod, J., Smith, S.D., Heslop, P., Metcalfe, C., Carroll, D., Hart, C.Are the effects of psychosocial exposures attributable to confounding? Evidence from a prospective observational study on psychological stress and mortality. J Epidemiol Community Health. (2001);55:878-884.
7.Sapolsky, R.M.The influence of social hierarchy on primate health. Science. (2005); 308(648); (doi: 10.1126/science.1106477).
8.Krieger, N. Epidemiology and the web of causation: has anyone seen the spider? Social Science Medicine. (1994);39(7):887-903.
9.Glass, T.A., McAtee, M.J. Behavioural science at the cross roads in public health: extending horizons, envisioning the future. Social Science and Medicine. (2006); 62:1657-1671.
10.Krieger, N., Zierler, S. What explains the public’s health?: A call for epidemiologic theory. Epidemiology.(1996);7(1):107-109.

Sunday, February 12, 2012

Extreme Diets: Perfect for Reality TV

I wrote my last blog post, Moving towards a whole foods, plant-based diet, after earning a degree in Public Health that focused on chronic disease etiology and prevention. Then I accidentally bumped into a book called The China Study. When I read that book, little did I know I would be thrown into a storm of nutritional chaos theory in which academics are coming to blows over which diets work, how to lose weight, or whether one can even lose weight at all. My professors didn’t even mention this controversy.  Here is my take on this contentious issue.

The basic controversy can be split into two major groups, the “meat is bad” group and the “meat is good” group. Yes, I know it is a bit more complicated than that, but in lieu of writing a dissertation I am simplifying the arguments. Nestled within the “meat is bad” crowd, you have the low fat people, some of whom eat chicken and pork but steer clear of red meats, some vegetarians—which include every imaginable dietary configuration—and the extremists, the vegans. They are pitted against the “meat is good” group, among whom you will find the anti-carb Atkins crowd, the just-plain-carnivorous steak-a-day people, and the ultimate in carnivore, the Paleo-people, some of whom actually run down their own food with spears.

Meat is Bad

First, let’s look at the low fat “meat is bad” crowd. I think it is pretty intuitive that meat feels unhealthy. It is slower to digest, and fat is clearly visible on the product. So it is not too hard to see their basic argument: fat from animals is high in saturated fats, the kind of fat that clogs your arteries, and, putatively, is a major cause of heart attacks. There are many observational studies that support this claim. However, the evidence is highly inconsistent. Two important details often skirted over are that meat has lots of the good fat, too, and that carbohydrates can affect blood cholesterol levels as much as meat.  We also can’t overlook the fact that high consumption of meat is associated with colon cancer. The mechanism is not fully understood, and it could be the nitrates in preserved meats and not the actual meat that causes colon cancer. Also, there are concerns that cows are an inefficient food source because the inputs (feed) outweigh their outputs (meat). So if everyone were a vegetarian, food costs would be lower and the world would be a better place. But the purpose of this paper is to discuss heart disease and obesity.

One troubling flaw in the “meat is bad” argument is that Americans have been eating less red meat and less saturated fat since the low-fat craze of the 1980s, yet obesity has risen to epidemic proportions. It is also a fact that when people switch to a low-fat diet they increase their carb intake. In addition, there is recent research showing that cutting out too much protein lowers lean muscle mass, which is not a good thing.
Then there is the issue of dairy. When people become vegetarian, most think they have signed on to a healthier lifestyle when, in fact, they often replace their meat consumption with dairy, in the form of cheese, milk, cream sauces, etc.  India is the country with the highest prevalence of vegetarians. Vegetarianism has been integrated into Hindu religious practices and culture for thousands of years, and people there get most of their protein from lentils and dairy. Yet India has the highest levels of diabetes and obesity in the world.

Then there is veganism. Vegans disavow all meat, dairy, and other animal products, and they are seen as higher up on the dietary purity pyramid. I have eaten in many vegan and vegetarian restaurants. Anecdotally, I find that many of these dishes have high levels of salt and/or sugar. I think this is because evolutionarily our palettes are wired for salty, sweet, bitter, and sour, and our cells need fat to rebuild. So we have evolved to crave these tastes, and when you eliminate one of those tastes, you need to replace it with more of another.  
But the real clincher in my questioning of the “meat is bad” perspective comes from the science. In 2010, a thorough meta-analysis published in a prestigious nutrition journal pooled the results of 21 well-regarded studies on saturated fats and health. It showed no significant effect in the relationship between saturated fats and risk of CHD or stroke.  This is definitely a big blow towards the "conclusion" that a low-fat diet is a healthy diet. It also demonstrates how intractable nutritional dogma is because the low-fat diet is still taught in medical schools and health science departments and appears in guidelines used by public schools.

These two dietary choices seem to be based more on romance than evidence, from the health perspective. (I realize there are other reasons, such as ethics and environmentalism, that people choose these diets.) I was never able to put my finger on it until I opened up my undergraduate biology textbook to prepare for a nature walk with my son’s 2nd grade class. I saw an intriguing diagram of the relationship between autotrophs and heterotrophs. An autotroph is any organism that makes its own food, e.g. plants through photosynthesis. Heterotrophs are organisms that cannot do this, which means every animal on the planet has to hunt for food, either by eating the autotrophs or by killing and then eating those who eat autotrophs. Obviously, we are heterotrophs, but we have brains that have adapted a conscience, which means we can see the purity of making our own food and conversely see the pain that killing causes. I believe that some people have a romantic desire for a “pure” diet that appeases their conscience.   

Meat is Good

At the other extreme is the “meat is good” argument, which is based on evidence that our early hominid ancestors began eating meat more than a million years ago and that, from an evolutionary perspective, our bodies have had time to adapt to a diet of meat. In contrast, humans have only been cultivating the land for grains and veggies for the last 11,000 years, which some argue is not enough time for our bodies to have adapted. Thus, it becomes highly unlikely that meat is the cause of our suddenly expanding waistlines. Some archaeologists believe that the adaptation to meat aided in our brains becoming larger.

Bolstering this argument is the fact that many primitive peoples, such as the Hadza and Inuit, have survived on diets of almost pure meat, and they rarely were afflicted with any of the chronic diseases associated with obesity until coming in contact with westernized foods such as refined carbs and sugar. Gary Taubes, author of Good Calories, Bad Calories (GCBC), brilliantly argues that dietary fat is wrongly accused as the culprit in heart disease and points the finger at sugar as the real killer. Taubes’s argument is very convincing. He is backed up by some of the most respected researchers in the field of nutrition who have published papers on taxing and regulating sugar, especially sugar sweetened beverages. Certainly from an evolutionary perspective, for many primitive societies, sugar was a seasonal delicacy and thus its consumption was regulated by nature. That sugar—particularly in drinks like syrupy lattes, white flour, and fried foods—is bad for you is not a contentious issue.

The flaws in the “meat is good” argument lie mostly in the extremes of their position. Look at the way Atkins demands stopping all carbs, at least temporarily, and the diet has produced a processed protein snack market. And although Taubes quietly acknowledges that there are good carbs and bad, his questioning of assumptions that fruit is healthy because no one has ever done a random controlled trial testing its efficacy distracts from his main message and leads people to dismiss his entire argument. Taubes is committed to his position and even posts his diet (bacon, sausage, burgers, and steak daily) and his triglyceride levels on his blog, but the fact that he enlisted a psychiatrist friend to order the tests strikes me as kind of weird.

Then there are the Paleo Diet people who really get into the purity aspect of man the hunter, the meat consumer. To me this position borders on Paleolithic fantasy, with romantic images of man the pure hunter carnivore. Although the idea that our bodies are adapted to eating meat is a valid argument, this camp just takes it to a level of impracticality so glaringly obvious that it’s hard to believe how zealous Paleo people can be. Humans have been genetically modifying food, wild or domestic, since we learned how to control our environment through selection and domestication. So it is impossible to find a truly sustainable Paleo diet on this planet. In addition, there is an unrealistic assumption that there was a homogenized caveman diet. Some Pleistocene era people lived near coasts and some in woodlands. Carbs and grains were certainly available. So again, I see this dietary choice as grasping for an unattainable purity on the other extreme.

Made for TV Confusion and Chaos

I could see people from both sides literally duking it out on the Discovery Channel. It might make for good television when science gets mixed in with zealots fighting over their extreme position, but I am tired of dietary purity and fantasy and I just want the facts. I just want to eat good tasting and healthy meals. So, to me the question really boils down to this: what would you do if suddenly you were diagnosed with coronary heart disease?

One reasonable voice can be found from the author, Richard Wrangham, who wrote the book Catching Fire: How Cooking Made Us Human. He makes a convincing case that cooking food maximized our caloric intake and thus freed humans to develop larger brains. Even Darwin said that cooking was humanity’s greatest discovery aside from language. The Paleo people are correct in that foods that are high in calories and low in nutrients (foods such as fast foods, candies, and frozen meals and that are abundant in obesogenic environments) are nowhere to be found on the African savanna. These are the kinds of foods that our bodies have not evolved to metabolize properly and, unfortunately, they are perfectly suited to our busy lifestyles. Meat is a whole food and it is something we have evolved to eat and digest. But that doesn’t mean eating a prime rib every night is great, and it doesn’t mean root veggies are going to make you fat.

Another way of looking at these extreme positions is seeing where they overlap. Consider a Venn diagram, with an overlapped area (below). This is where both arguments tend to agree on a whole-food diet and both also agree that highly processed foods are not healthy. So really the BIG disagreement is that at one extreme, eating meat is bad and at the other, it is good, with a whole spectrum in between. In this situation, I stick to the center, the overlapped area. Based on current available evidence, controversial as it is, I believe we need to stick to a traditional balanced diet that includes meats and lots of good carbs, such as whole grains, fruits, and veggies.

This validates the Italian-American food values I was raised with. My family believed in eating fresh, whole foods.  There wasn’t a focus on meat, but it was never demonized or romanticized either. I am now inspired to continue with that tradition of making well-balanced, home-cooked meals with fresh ingredients.  We all must find some common ground and admit that using less sugar and salt, very little white flour, limiting alcohol to a drink or two per day, and increasing veggie consumption are the safest bets for health. Personally, I’d stay away from extreme diets, like Atkins, Paleo, and veganism. Many of those diets have some research behind them, and they are not totally implausible, but they always seem to go out further that the evidence suggests. As the prominent scientist Medawar once said, “The intensity of the conviction that a hypothesis is true has no bearing on whether it is true or not.”