Tuesday, March 6, 2012
Jeffrey Anshel, OD
Optometrists have a long history of balancing their professional services and dispensing products. Since our very beginnings, we have offered the patient eyeglasses and then contact lenses to facilitate their transition from faulty to excellent vision.
The area of nutritional support for visual disorders is a rapidly growing area of eye care. This trend offers the practitioner another avenue for specializing a practice that offers the best of traditional and complimentary vision care. This also represents another area for the practitioner to offer patients the convenience of purchasing their products under the supervised auspices of the doctor.
Nutritional supplements can fill the gaps in nutrient intake that most Americans experience. Recent studies show that less than 5% of the population actually eats the nine to 13 servings of fruits and vegetables that are now recommended by the U.S. Food and Drug Administration. In 2009, more than $26 billion was spent on nutritional supplements and herbal products, with more than half the U.S. adult population using dietary supplements. Most supplement users take them every day.
While conventional medications certainly have their place, many practices choose to integrate nutrition that can serve to support their treatments. This process is called “integrative optometry,” whereby conventional and alternative therapies are both considered appropriate. This philosophy neither rejects conventional medicine nor accepts alternative therapies uncritically. Many patients prefer the use of natural, effective and less invasive interventions whenever possible. This process also shows that you are being respectful to your patients, listening to their health concerns and taking their concerns seriously, as well as using good medical judgment.
The first thing you must ask yourself is whether you think there is real science behind this nutrition stuff. To say the least, there is confusing data and reporting on the effects of nutritional ingredients and products. One day you’ll hear that a specific nutrient is effective in helping with a particular condition and the next day you’ll hear that it isn’t. So how do we sort out the real science from the marketing hype?
The gold standard for establishing the efficacy of pharmacologic agents is the randomized controlled trial (RCT). However, this is poorly suited to the evaluation of nutritional effects for several reasons.
First, chronic diseases have long latency and multifactorial causation, so it is difficult to determine exactly when a disease process begins and how long it has been developing. Without knowing a starting point, it’s difficult to say when some treatment can be effective in preventing a disorder.
For the most part, nutrients interact with one another, whereas drugs are designed to work alone. All foods contain a variety of nutritional ingredients that are designed to work synergistically; we don’t eat spinach just because it contains lutein, for example.
We would like there to be only one target tissue with drug therapy, but side effects do occur. Nutrients act in modest beneficial ways in virtually every body system; drugs act potentially on single targets (the RCT is designed for single outcomes).
Many studies performed on nutrients are considered “observational” studies, which also have their limitations. For an observational study there is the absence of a “no exposure” group. One cannot require subjects in a study to not take a specific nutritional product for an extended period of time; there can only different levels of intake. For example, we couldn’t ask one group of participants to stop taking vitamin C for several years and see how they fare.
Uncertainty in quantitative measures of food intake due to inaccurate reporting and recall bias is often the case. Most studies ask participants to use food-intake questionnaires. Often the subject fails to accurately record the type and amount of food eaten or they forget and attempt to recall at a later time. Some studies actually record food intake at the beginning and end of a particular study and assume that the subjects are eating similarly throughout the entire duration of the study.
In addition, how this food is translated into nutritional intake may be questionable. Depending on where the food was grown, how it was ripened, whether it was organic or not and even the weather conditions can affect the potential nutrient values of a particular food.
The next blog will review some of the regulatory issues surrounding nutrient products.
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