Monday, November 29, 2010

Antioxidants, Medical Wizardry or Wizard of Oz?

    In the past decade health foods have taken on a huge chunk of the food market. We, some of us anyway, have come to terms with our terrible eating habits and their consequences. The average person understands that eating a block of butter with fried chicken isn't the best way to keep the pounds off. Still, America is well known as the planet's fattest nation. With more people realizing that the fattest nation crown isn't something to be proud of, Americans are turning to this new, healthier, section of the food market. There are many different types of so called health foods; organic produce, free range poultry, low fat and low calorie snacks, and foods, fruits mainly, that are said to contain antioxidants. I've found simple answers to most of these health food choices, such as, foods marketed as hormone free are no different than those that are not marketed in the same manner. Hormone use in livestock is illegal, and the use of vaccines does not carry over into the milk or meat of livestock in any significant amounts, if any at all. Organic foods have a similar diagnosis, but these are for another day. The major health craze that I didn't know much about, and couldn't find readily available information on, was something called antioxidants.

      Antioxidants are said to protect our cells from what is called oxidative stress, caused by compounds called free radicals. Walk into any grocery store and you're bound to come across at least one product, on every isle, that claims to contain these protective antioxidants. The best source of abundant amounts of antioxidants is said to be fruits and vegetables. Fruit juices and dietary supplements designed to contain copious amounts of antioxidants are also a competitive source. Product labels with the words "Antioxidants" or "Free Radicals" stand out among similar products without these reassuring terms. Commercials claiming the power of "Super Fruits," brag about the high concentrations of antioxidants contained within. Other than the power to block free radicals labels rarely, if ever, speak about just how these compounds work to extend our life spans. We are only told that diseases like arthritis, chronic fatigue, Alzheimer's, and most especially, cancer can be avoided by supplementing your diet with large amounts of antioxidants. Even the phenomenon of aging is said to be no match for antioxidant power. It was these claims that caused me to look deeper into the inner workings of these miracle compounds. Claims of all powerful and all curing substances in the medical field tend to turn out as snake oil. To start, I truly hoped that antioxidants wouldn't follow suit, but the more I dug into the complicated world of cell energy production, the bleaker antioxidant's claim of medical efficacy became. I have to say, it was a hell of a ride researching the mechanics that antioxidants supposedly act upon, and reading through the published studies containing the data that could exonerate, or condemn, antioxidants for good.
    Let's start slow, slow and easy. First, what the heck is a free radical anyway? A free radical is an atom that has an odd number of valance electrons, creating a negative charge. This negative charge causes the atom to seek out and quickly bond to a positively charged atom. Oxygen atoms happen to be the main culprit in cell oxidation (that's why it is called oxidation). This is why we find atmospheric oxygen as 0₂. Two oxygen atoms bonded together to form a balanced compound of oxygen. Free radicals can also bond to atoms that, once oxidized, create unwanted results. Rust is a commonly known result of this action. Rust, a compound of iron and oxygen, is also called iron oxide or, a less comprehendible, Fe2O3. These same oxygen atoms are the crucial link between antioxidants and health. The oxygen free radical is produced during normal cell function; I'll get to this in a moment. The theory is, some of these break off from the cycle and wreak havoc on our cells. Well, sometimes they do, the question is how often, and how much damage do they really cause.

    Now to cell function and what it has to do with free radicals. As you probably already know, our bodies are made up of cells, lots of them. Different body parts have different cells; your liver is made of liver cells, kidneys of kidney cells, and so on. These different cells have different jobs, but they all need to generate energy. They do this through chemical chain reactions or the electron transfer chain. Basically, a compound is broken down, this releases energy, these compounds or atoms either break down again or attach themselves to other compounds. Each time this happens, a little energy is released and used by the cell. It's an incredible process, and I haven't given it anywhere near the justice it deserves. This is where oxidation takes place. Oxygen atoms are dropped off and picked up over and over again in the chain reaction. As we all know, nothing in nature is perfect. So an occasional freed oxygen atom, or free radical, escapes this reaction and attaches to a compound making up the structure of a cell. When this happens it is called oxidative stress. If our cells take on too much of this, and didn't have some resistance to it, they would became damaged and die. That's bad, really bad if it happens a lot. Lucky for us, our cells and the cells of other organisms have built up defenses to this natural occurrence. If they hadn't, no critters would be around to tell the tale.

    This is just the point where antioxidant supplements are supposed to step in and do their thing. Antioxidants attach themselves to the free radicals, there's a little magic, and boom, no free radical worries. Maybe there isn't any magic, but that's the simplest way to explain it. The Wiki article on antioxidants has a far more in depth description of the process that highly recommend you take the time to read. Antioxidants such as uric acid are naturally made by our body. Some, like uric acid, can even have adverse effects in high concentrations. Large amounts of uric acid are the cause of gout. Here is where the aging and disease theories of free radicals split away from science. Ingesting more antioxidants by eating fruits, vegetables, and supplements is said to send more free radical police to our cells. The problem is, our bodies make all the antioxidants we need, and having to many antioxidants in our bodies can cause hiccups in the chemical chain reactions they depend on. There is also the problem of cell resistance. Like our immune system, cells build up natural immunities to both internal and external free radicals. It is the internal free radicals that begin the construction of this important resistance. When you turn down the volume on internally produced free radicals, cells become less efficient at dealing with the externally introduced baddies. The loss in efficiency negates any benefits from repelling internal free radicals.

    My favorite study on the efficacy of antioxidant supplements is a meta-analysis on a large number of other studies. The studies were focused on longevity benefits in seniors, and many recorded the effects on the prevention of multiple diseases. When all the information was combined, it seemed there was a slight benefit to supplementation. Sadly though, when only the high quality studies that were also the least biased, the only ones that should hold merit anyway, were separately reviewed; it turned out that a marked decrease in overall longevity and disease resistance was found in the participants that were given antioxidant supplements. This is strong evidence that the idea of lowered external resistance negating benefits could be on the right track. It also seems that not only is there no effect, but there is a negative effect in those that received very high amounts of supplements. Another study reviewed the diets of over 400,000 Europeans. Because antioxidants are said to lower your risk of cancer, this was what they tested for. They compared the cancer rates among the subjects that ate large amounts of fruits and vegetables against the rate of those who only ate a normal, balanced, diet. This study come to the same conclusion as the last, there was no evidence to suggest any benefits in cancer resistance from consuming large amounts of antioxidants. So you don't think I'm cherry picking, I did come across a 1998 study that found a 10% increase in the max life span of mice given supplements. It seems there is a flaw in this study though, because no one has been able to reproduce the results in a separate lab test. Not even the originator of the entire antioxidant craze, Denham Harman, who spent decades attempting to show this correlation. It seems the jury is in on this subject.  Antioxidants as a miracle drug is nothing more than the Wizard of Oz, just a lonely old coot behind the giant facade of media hype.
    Our mortality is the greatest cause of irrational thinking. We attempt to avoid it in any way possible. Elaborate stories of gods and afterlife have been told since we first gathered together around the fire. The knowledge that we will one day be no more, can be terrifying. As anyone that has watched a bad slasher movie knows, people do dumb things when they're terrified. This includes the things we decide to believe without first examining the evidence; because the evidence could hold a truth that only validates our fear. So it is easy for charlatans that understand this fear, to prey on our ever growing ignorance of science. They only need a handful of intellectuals, real or not, to support their claims and we are hooked. Our only weapon against these predators is skepticism, skepticism that will lead us to investigate the evidence for ourselves; then we can make informed decisions about such claims. 

"If it were widely understood that claims to knowledge require evidence before they can be accepted, there would be no room for pseudoscience."
—Carl Sagan

As always, please feel free to e-mail me with questions, comments, corrections, and requests for references.