All of the respondents to this survey indicated that they provide nutritional advice or counselling to patients, and 99% provide dietary supplement recommendations. Similarly, a 2009 survey of 2371 chiropractors across the United States indicated that 94% provided nutritional and dietary recommendations[5]. In a survey of 125 New York chiropractors, Holtzman and Burke found that 80% of respondents utilized nutritional counseling in their practices, and dietary supplement prescription was the most common form of such counselling[4]. Respondents were asked to estimate the percentage of their patients to whom nutritional advice or counselling was provided (31% on average) as well as the percentage of patients who received dietary supplement recommendations (25% on average). These rates are lower than those reported by 74 American chiropractors in a 2001 survey, who provided nutritional counselling to an average of 37% of their patients, and recommended dietary supplements to an average of 50% of their patients[6].
Although dietary supplement recommendation to patients appears to be common amongst Saskatchewan chiropractors, only a small number of dietary supplements are frequently recommended (glucosamine sulfate, multi-vitamins, vitamin C, vitamin D, calcium, omega-3 fatty acids, and probiotics). These results are not substantially different from the findings of Hetherwick et al. that the most commonly recommended nutrient-based dietary supplements by California dietitians were calcium, multi-vitamins with or without minerals, vitamin E, vitamin C, and iron[7]. Their most commonly recommended herbal supplement was Echinacea, a finding supported by Cashman et al. in their survey of Massachusetts dietitians[7, 11]. Conversely, nearly half of the current survey respondents indicated that they “rarely” or “never” recommend Echinacea. Interestingly, a recent review indicates that Echinacea may be effective in reducing the duration and severity of a cold[12].
When considering the types of health conditions for which respondents recommend dietary supplements, there was a level of concurrence with the specific supplements being recommended. The most common reason for recommending supplements to patients was for “general health and wellness” (by 82% of respondents), which is reflected by multi-vitamins, vitamin C, and probiotics being among the most recommended supplements. Vitamin C has been found effective in preventing the common cold[12], however there is conflicting and insufficient evidence to date regarding the use of multivitamins[13–15] and probiotics[16, 17] for the prevention and treatment of different health conditions. The next most common reason to recommend supplements was for “bone health” (74%), which is reflected by vitamin D and calcium being frequently recommended and well supported in the literature and by clinical practice guidelines[18–20]. Omega-3 fatty acids and glucosamine sulfate were also commonly recommended by respondents, and this may be a reflection of their frequently recommending supplements for “rheumatologic, arthritic, degenerative, or inflammatory conditions” (72%) and “acute and/or chronic musculoskeletal conditions” (65%). However, there is conflicting evidence surrounding the use of both omega-3 fatty acids[21–24] and glucosamine sulfate[25–27] for such conditions. Holtzman and Burke found that the most common conditions for which New York chiropractors provided nutritional counselling were osteoarthritis (by 76% of respondents) and osteoporosis (71%), followed by obesity, diabetes, coronary artery disease, fibromyalgia, and allergies (each at least 50%)[4].
In comparing the current results to other health professions, a recent survey of American dietitians found that the most common reason for recommending supplements by this group was bone health (70%), followed by filling nutrition gaps (69%), overall health and wellness (49%), lowering cholesterol (46%), cardiac health (46%), dietary pattern reasons (for vegetarians or vegans for example, 43%), and digestive health (39%)[8]. Dickinson et al. surveyed 900 physicians (including 300 general practitioners) and 277 nurses, and the three most common reasons these groups recommend dietary supplements to patients were for overall health and wellness (41% of physicians and 62% of nurses), followed by bone health (41% and 58%, respectively) and joint health (37% and 37%)[9]. In a survey of 300 cardiologists, 300 dermatologists, and 300 orthopedists, the most common reasons that each group provided for recommending dietary supplements was reflected in their professional specialty[10]. For example, the cardiologists’ most common reason for recommending dietary supplements was to lower cholesterol (58%), followed by heart health (55%) and maintaining healthy cholesterol (36%)[10]. Dermatologists most frequently recommended dietary supplements for skin, hair, and nails (81%), followed by overall health and wellness (30%) and bone health (25%). Orthopedists most frequently recommended dietary supplements for bone health (75%), followed by joint health (73%) and musculoskeletal pain (53%)[10]. The findings from the current survey reflect the trends observed in these surveys in that “general health and wellness” was the most commonly cited reason for Saskatchewan chiropractors to recommend supplements to patients, followed by “bone health”, “rheumatologic, arthritic, degenerative, or inflammatory conditions”, and “acute and/or chronic musculoskeletal conditions.” It is reasonable to expect chiropractors’ recommendations to parallel those of orthopedists as both groups predominantly treat patients with musculoskeletal and degenerative conditions, and this does appear to be the case. However, chiropractors seem to have a substantially greater tendency to recommend supplements for “general health and wellness” than do orthopedists (82% versus 25%)[10].
Postgraduate education in nutrition
Smith and Spillman found that their chiropractor respondents had completed 84 postgraduate nutrition hours on average[6], while the majority of respondents to the current survey had taken between one and five postgraduate courses on nutrition and 28% had completed at least six postgraduate nutrition courses. A small minority of respondents (6%) had completed formal postgraduate qualification (certificate, fellowship, diplomate, graduate degree) in nutrition. Holtzman and Burke[4] found that 65% of their chiropractor respondents did not feel that they had received adequate education in nutrition, and 47% of the respondents in Smith and Spillman[6] felt similarly. Although the current survey’s respondents were not asked to rate the perceived adequacy of the nutritional education in their chiropractic training, these previous survey findings may in part explain why so many respondents have augmented their education with postgraduate training in nutrition.
Referral rates to and from other health professionals
A 2009 survey of chiropractors in the United States indicated that chiropractors refer patients to nutritionists and receive patient referrals from nutritionists at a frequency between “Never” and “Rarely” (<1/month), while patient referrals to and from family practitioners occurred at a frequency between “Rarely” and “Sometimes” (1-3/month)[28]. The findings from the current survey are in line with these, as respondents indicated referring a higher percentage of their patients to medical doctors (6% of their patients on average) and naturopathic doctors (11%) for dietary or nutrition-related concerns than to dietitians or nutritionists (3% each).
Study strengths and weaknesses
The response rate of this survey was 45%, which is low, but still within the anticipated range for surveys of chiropractors[29]. Previous surveys of chiropractors regarding nutritional and dietary supplement recommendations have obtained response rates varying between 13% and 34%. The current study actually had the highest response rate of chiropractors thus far on this topic, making it difficult to necessarily validate the results of the current survey against those conducted previously[4–6]. Numerous steps were taken to encourage a higher response rate, such as pre-notification, and multiple contacts, both in person and through e-mail messages[29]. Respondents to this survey were practicing chiropractors from only one jurisdiction in Canada, which limits the ability to generalize results to other North American jurisdictions. Additionally, not all of respondents answered all of the survey questions, creating a level of uncertainty for those particular results.
Furthermore, while this survey did inquire about different reasons for respondents to recommend dietary supplements, it did not ask respondents to directly relate these reasons to specific supplements. Additionally, the list of supplements occasionally did not necessarily correspond to those different reasons. For example, none of the listed supplements would be considered to be specifically targeted towards “weight loss or management”, which was mentioned as a reason for recommending supplements by 36% of respondents. In addition, all of the survey respondents indicated providing nutritional advice or counselling to patients, and nearly all respondents provide dietary supplement recommendations to patients. These data lead to a concern of some degree of selection bias where only those who do recommend supplements or provide nutritional advice or counselling chose to complete the survey. As mentioned previously Table 1 indicates that the survey respondents do not appear to be essentially different from the entire population of Saskatchewan chiropractors from a demographic standpoint, thus it is unclear if there is any bias in the results due to non-response.
