Volume 80, Issue 10 , Pages 587-589, October 2009
Nutrition counseling in the optometric practice
Article Outline
The AOA Optometric Clinical Practice Guidelines on Care of the Patient with Age-Related Macular Degeneration now recommend optometrists counsel patients on the importance of proper nutrition, in line with the findings of the Age-Related Eye Disease Study (AREDS). Here is how optometrists can effectively counsel patients on the benefits of good nutrition for eye health.
The new AOA practice guidelines will recommend patients be counseled on the benefits of proper nutrition based on the findings of the NEI-sponsored Age-Related Eye Disease Study (AREDS). Released in 2001, the study provides evidence that several antioxidant vitamins and minerals—vitamins C and E, beta-carotene and zinc – taken in high doses by mouth, can reduce the risk of progression to advanced AMD by 25% and the risk of moderate vision loss by 19% in specific patients over a 5-year period. As a result, the study recommends that, at the very least, patients at risk supplement their diets daily with what has become known as the AREDS Nutritional Formulation:
The formulation also calls for patients to take 2 mg of copper per day, because zinc supplementation has been shown to interfere with copper absorption.
The pending inclusion of the AREDS Nutritional Formulation in the AOA Optometric Clinical Practice Guidelines is indicative of the importance now placed on proper nutrition as a factor in preventing or minimizing AMD, according to principal author Anthony A. Cavallerano, O.D. Debate remains over exactly what formulation of nutrients may be most beneficial to patients. Research conducted since the AREDS study suggests that the nutrients lutein and zeaxanthin, as well as the omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), might also be beneficial in preserving the integrity of the macula. There is also ongoing debate over possible adverse effects of certain nutrients and dosage levels. Nutritionists caution that large doses of virtually any vitamin or mineral may affect the body's ability to absorb other nutrients and can be associated with some health risks. High doses of beta carotene, included in the AREDS formulation, have been associated with increased risk of cancer in smokers. For example, high doses of zinc, also included in the AREDS formulation, can cause prostate enlargement, and some laboratory evidence suggests it can increase risk for Alzheimer's disease. The NEI in 2006 initiated a second major study, AREDS 2, to test a modified nutritional formulation that includes lutein, zeaxanthin, DHA, and EPA but with reduced intake of zinc. Results of the AREDS 2 are not expected to be available for at least 5 years. However, with proper nutrition now widely recognized as a critical factor in AMD care, virtually every eye care practitioner should be prepared to provide nutritional counseling for appropriate patients, Dr. Cavallerano emphasized.
Relatively few practitioners are counseling patients on nutrition now, Dr. Cavallerano acknowledges. In many cases, practitioners may feel they do not have the time to provide nutritional counseling to patients. Many others may feel they do not know how to offer such counseling, he believes. However, nutrition counseling can be efficiently and effectively implemented in virtually any practice, according to suburban Chicago practitioner Robert L. Davis, O.D. “I have a contact lens practice,” he notes. Several years ago, Dr. Davis adjusted his practice protocols to better identify patients who may be at risk for AMD and then provided those patients appropriate counseling on nutrition and lifestyle changes. The system is neither time consuming nor complex, he adds. It is, however, beneficial to both the patients and practice, he emphasizes. “Determining the risk for macular degeneration and providing appropriate counseling allows us an opportunity to perform our job of protecting our patients,” Dr. Davis said.
Identifying appropriate patients
Nutrition counseling should be provided not only to those who have AMD but those at risk for the condition, Dr. Davis emphasizes. Most practitioners rely on patients' family histories to determine who may be in danger of macular degeneration. However, “genetics is not enough,” Dr. Davis contends. Practitioners must consider other risk factors, including systemic conditions (such as diabetes or high blood pressure), environmental factors (such as sun exposure), age, smoking, obesity, and diet. Based solely on patient history, a practitioner may identify and provide appropriate counseling for only a portion of the patients who are actually at risk for AMD. Conversely, because not every patient who is genetically predisposed to AMD will actually have the condition, assessing risk solely on the patient histories can cause practitioners to recommend dietary and lifestyle changes for patients who do not really need them, he said.
Dr. Davis believes the best way to identify patients at risk for AMD is to use the latest technology and measure macular pigment optical density (MPOD). A growing body of evidence has established a link between good nutrition and MPOD. Additional research suggests a link between low MPOD and risk for AMD. Those studies suggest MPOD measurement may be a reliable way to identify individuals with, or at risk for, early-stage AMD. Several techniques have been developed for measuring MPOD, including heterochromatic flicker photometry, resonance Raman spectroscopy, and autofluorescence imaging. Several devices are now commercially available to measure MPOD using heterochromic flicker photometry. MPOD measuring equipment is now being used in fewer than 1,000 practices nationwide, according to a source close to the industry, largely because research on the use of that equipment is ongoing and, in many cases, peer-reviewed studies on their use have yet to be published. The literature review, “Macular pigment and healthy vision,” in this issue of Optometry, outlines pertinent research to date. Dr. Davis is among the practitioners already using an MPOD device in the field.
In Dr. Davis' office, MPOD measurements are taken by paraoptometrics during the pretesting period (referred to in his office as “data collection”) along with color vision, intraocular pressure (IOP), blood pressure, and visual field measurements. The MPOD measurements are compiled in about 3 minutes, Dr. Davis said. Data from the digital units can be easily transferred directly into electronic patient health records. Dr. Davis considers MPOD testing a routine part of an annual eye examination and does not charge an additional fee.
Once the pretesting is complete, the patient is taken to the examination room. MPOD measurements are reviewed by the practitioner and discussed with the patient along with IOP, visual fields, blood pressure, color vision, and other test results. Dr. Davis provides at-risk patients an explanation of AMD, its risk factors, how proper nutrition is important in preventing the disease, and the dietary or lifestyle changes that may be necessary to minimize its effects.
Many eye care practitioners consider MPOD measurement to be a useful diagnostic tool that will identify patients who are at risk for AMD, Dr. Davis notes.
MPOD testing is still the subject of research, so not all practitioners may wish to implement it at this time, he acknowledges. However, with or without MPOD results, virtually any practitioner can counsel patients on nutrition, he adds.
Consultation
Eye care practitioners can cover the pertinent nutrition and lifestyle information concisely in a matter of minutes, Dr. Davis said. The article “What eye care patients should know about nutrition,” which follows in this issue of Optometry, offers an overview of the information practitioners may wish to provide. Dr. Davis makes it a point to explain the specific nutrients necessary to minimize AMD. He emphasizes that proper diet is the ideal way to ensure proper nutrition. He notes that the federal government recommends people eat 8 servings of vegetables each day. He is then careful to provide specific examples of the types of foods that can provide the nutrients necessary to prevent or minimize AMD. “Inform at-risk patients that lutein and zeaxanthin may be helpful in minimizing AMD and that it can be found in dark green leafy vegetables and colored fruits, but be sure to include specific examples such as spinach or romaine lettuce. Don't just mention colored vegetables and fruits but specific examples like orange peppers and corn. We want to make sure patients know what they are going to shop for when they go to the grocery and the choices they can make when they go out for dinner,” Dr. Davis said.
Dr. Davis then generally notes that while the government's recommended daily allowance of vegetables may be 8 servings each day, Americans eat, on average, only 2 servings. For that reason, patients who are at risk for AMD may find it advantageous to take a nutritional supplement, he explains. A number of nutritional supplements have been developed specifically for patients who are at risk for AMD, each with a different formulation of nutrients. (For a listing of the various supplements available, see the Lutein: Facts about nature's nutrient for healthy eyes brochure or other resources outlined in the “Information on nutrition and eye health” article which appears in this issue of Optometry.) In addition to providing information on nutrition, Dr. Davis also counsels the patient on lifestyle factors, including smoking, protecting the eyes from phototoxic light, and the benefits of daily exercise. A sedentary lifestyle can contribute to risk factors for AMD including high blood pressure, diabetes, and obesity, he notes. He notes that because fat tends to absorb nutrients such as lutein and zeaxanthin, obesity can contribute to macular degeneration by starving the eyes of necessary nutrition. In addition, it can render the efforts to supplement the diet effectively useless. “Even if you use a dietary supplement, the nutrients will just be trapped in the fat, and they will never reach the eye,” Dr. Davis said.
Not just AMD
In addition to being beneficial to those at risk for AMD, good nutrition and dietary supplements can be useful in maintaining the health of the crystalline lens; thereby delaying the onset of nuclear cataracts, Dr. Davis notes. Nutrients such as lutein and zeaxanthin help to delay the progress of nuclear cataract formation by removal of free radicals with its antioxidant properties. Supporting data can be found in the Women's Health Initiative study, NEI multivitamin trial and the Blue Mountain Group Study undertaken by the University of Sydney, Australia, he notes.
Summary
Typically, a nutrition and lifestyle consultation takes “a few minutes,” Dr. Davis said. “Be very clear, very direct,” he advises. He generally concludes the examination by providing the patient some literature on AMD and proper nutrition (see Figure 1 and “Patient education resources” in this edition of Optometry). He also offers product literature on the specific brand of nutritional supplement recommended.
Figure 1
Excerpt from AOA “Recommended Nutrients for Healthy Eyes” brochure.
Nutrition counseling is generally well received by patients and is, more often than not, effective, Dr. Davis believes. Patients seem to understand the information. On returning for their next visit, many patients report they have been eating healthier meals, supplementing their diets with nutrients as recommended, and exercising to control their weight (sometimes with easily verifiable results), Dr. Davis said. Patients enjoy being retested with the MPOD device at the 6-month follow-up visit to validate and check the therapeutic effects of supplementation, he adds.
In addition, nutrition counseling “tends to change the patient's perspective on what we, as optometrists, do,” Dr. Davis notes. “We find our patients come to view us more as health care practitioners, instead of just an office they go to for eyewear, and look to us for care and guidance on a range of eye health issues. They understand better the role we play within the health care system.”
“Nutrition counseling in the right thing for the patients and our practice,” he says.
Opinions expressed are not necessarily those of the American Optometric Association.
PII: S1529-1839(09)00424-2
doi:10.1016/j.optm.2009.08.005
Volume 80, Issue 10 , Pages 587-589, October 2009
