Natural health product use in Canada

Natural health product use in Canada

Leticia Troppmann

Natural Health Products (NHPs) include “traditional herbal medicines; traditional Chinese, Ayurvedic and Native North American medicine; homeopathic preparations; and vitamin and mineral supplements”.1 While U.S. studies consistently report that 40% of adults use some form of vitamin or mineral supplement2-4 and 13% use herbal preparations,5-7 data concerning the prevalence of use in Canada are lacking.

Dietary supplements may be used to enhance dietary quality, prevent disease or as a natural remedy for health problems. The new Dietary Reference Intakes (DRIs) recognize both the role of diet and of supplemental forms of nutrients in health promotion (e.g., synthetic folic acid used prior to and during early pregnancy to prevent neural tube defects (NTDs)).8 Within the context of DRIs promoting synthetic nutrients and a booming herbal supplement market, 9,10 obtaining information on supplement use presents a practical challenge to healthcare professionals.

Currently there is limited government regulation of supplements and few scientific reports on the efficacy and outcomes of NHPs used in Canada. Moreover, consumers lack knowledge concerning appropriate use, with even the most common herbal supplements such as Echinacea being used at inappropriate levels.11 The Natural Health Products Directorate (NHPD) has been mandated to address these issues, yet there is limited background available on current NHP use in Canada. The following report offers the first insight into the usage habits and characteristics of Canadian users.

METHODS

Sample design

The Food Habits of Canadians randomly selected and interviewed 1,543 (572 men, 971 women) Canadian adults aged 18-65. Eighty sample areas, representative of the Canadian population, were randomly selected using a probability of selection based on population size, from each of 5 regions, 4 census divisions, then 2 subdivisions and finally 2 enumeration areas. Using a telephone listing, the adult in the household with the next birthday was invited to participate in the study. Fifteen percent of the population isolated from major population centres and Aboriginal communities were excluded, as were pregnant and lactating women. Low-income individuals and young males had lower response rates. Twenty-four hour recalls were conducted in the home by a dietitianinterviewer, inquiring about the use of any dietary supplements on the recalled day. Full sampling methods and dietary intakes with and without nutritive supplements have been described previously.lz.12,13

Variables

Data were analyzed in mutually exclusive categories of NHP use: non-users (NU), nutritive supplement only users (N), nutritive and herbal supplement users (NH), and herbal supplement only users (H), as well as by specific supplement user types (e.g., multivitamin users). Each group was compared to non-users using Chi-square tests for proportions and independent t-tests of means.

“Nutritive supplement” was defined as any supplement containing at least one micronutrient, with or without “herbal” content. Herbal (i.e., non-nutrient), whether or not said component (e.g., glucosamine sulfate) met the strict definition of an herb, identified those supplements with at least one component with no established nutritive value by acknowledging their predominant botanical derivation.

For nutritive supplements, multivitamins with or without minerals were grouped together. Vitamin B-complex preparations included B, (containing 50 mg or pg of most B vitamins) and other B-vitamin formulations. Calcium supplements were those listing calcium as the main label ingredient. For herbal supplements with 2 or more main label ingredients (e.g., “garlic with lecithin”), each ingredient was counted separately. Products not listing specific components (e.g., “herb alive”) were recorded as herbal mixes.

Age and education were each stratified into three levels: 18-34, 35-49 and 50-65 for age, and

RESULTS

Of those surveyed, 41% used at least one NHP on the day in question (Table I). Women were more likely than men to take supplements. At least one nutritive supplement (N + NH) was used by 29% of men and 43% of women, while 13% and 16% used at least one herbal supplement respectively (NH + H). Women were more likely than men to use nutritive supplements (N + NH; p=0.001) but there were no gender-based differences in the use of herbal supplements (NH + H).

The average age of both male and female supplement users was higher than nonusers (p

Women selected multivitamins, calcium and vitamin C, in ranked order, while men used vitamin C, multivitamins and vitamin E (Table II). The top herbal products were garlic, herbal mixes and evening primrose oil. Among supplement users, use of iron, calcium supplements, B-complex vitamins, evening primrose oil and glucosamine sulfate was significantly higher among women (p

Fifty-seven percent of users took more than one supplement, not different by gender, with the highest number consumed by one individual being 12 (6 nutritive, 6 herbal). Seventy-six percent of individuals using at least one herb also consumed a nutritive supplement, however the inverse was not true with only 29% of nutritive supplement users taking an herbal supplement.

Lifestyle/Health

Supplement users overall (N + NH + H) and category H users had a better selfperceived health rating than non-users (p

Vitamin C, garlic and B-complex users were equally likely to smoke as non-users. Multivitamin users of both genders and Echinacea* users were significantly less likely to smoke as were women taking calcium supplements and men taking vitamin E (p

DISCUSSION

Canadians use a wide range of NHPs with users consuming multiple nutritive or a combination of nutritive and herbal supplements. Women were more likely to take supplements than men and use increased with age. Supplement users had a lower rate of smoking and better self-perceived health than non-users and supplement choices reflected gender- and age-related health concerns.

Relative use

With similar findings to NHANES and CSFII data, our study demonstrates that Canadians consume nutrient supplements at a rate similar to Americans (38% vs approx. 40%, respectively).2,4 Our prevalence of herbal supplement use, 13% for men and 16% for women, was also similar to the 13% rate reported in the U.S.5,7′ Use is shown to peak in the 50-65 age category at a rate which is maintained in older persons for nutritive supplements but declines for herbal supplement use.2,114

While the enormous sales growth of herbal products from 1994 to 1999 might suggest our data underestimate current prevalence of use, over the previous decade the prevalence of use in the U.S. has not increased in relative proportions with NHANESIII (1988-1994) findings similar to NHANESII (1976-1980).2′ Because supplement users are long-term users and often consume >1 supplement, the sales growth may be attributed to increased use by existing consumers.’S 15,16

Sample size prevented stratification by gender.

Types of supplements

Consistent with U.S. data,2,4,7,17 multivitamins, calcium, vitamin E and vitamin C are the top four nutritive supplements in Canada. Among our top Canadian herbal supplements were garlic, Echinacea, ginseng, evening primrose oil and ginkgo biloba, also found in the top 10 listed in American sales reports.9″‘ Importantly, however, goldenseal, St. John’s Wort and saw palmetto were not ranked high in our study but are ranked consistently high in U.S. sales. Such discrepancies raise methodological considerations for future research and issues for health care. First, we question the accuracy of self-reported herbal supplement use. With only 11 reports of St. John’s Wort and 2 of saw palmetto in our study and similarly low numbers in NHANESIII data, self-reported data have not detected the use of these herbs, which are ranked high in dollar sales during the study periods. 10,11-2’ These herbs may not be reported given the stigma associated with the conditions they treat depression and enlarged prostate, respectively.21 We also failed to detect psyllium and creatine use, which may reflect the age distribution of our sample. Psyllium use is common in the elderly as a natural laxative with use increasing by age, while creatine use, for muscle building, is primarily used by young males, who responded at a lower rate to our survey.22-24

Second, market reports are based on sales ($) and given the varied price for herbs cannot directly reflect prevalence of use. As 19 pounds of garlic ($U.S. $2.60/lb) must be sold to equal 1 pound of goldenseal ($U.S. $50.00/16) sales, much less goldenseal must be sold to establish a high sales rank.25 Discrepancies may also reflect differences between Canadian and U.S. markets. Goldenseal (grown only in a narrow region of the North-eastern States and Southern tip of Ontario) is protected under CITES.* Most U.S. export permits were denied during the study period, preventing the importation of U.S. goldenseal into Canada (Bertrand Vonarx, Scientific

Authority CITES and International Coordinator, Government of Canada) and may thus have affected the herb’s availability. As research does not investigate the impact of trade restrictions on market trends, American sales data may not be a good marker for Canadian supplement use.

Patterns of use

Supplements commonly used by older women included calcium, glucosamine sulfate and garlic, used for the age-related diseases of osteoporosis, osteoarthritis and heart disease respectively. Women were also the main consumers of evening primrose oil (EPO) and B-complex vitamins, corresponding to EPO and pyridoxine’s common application in treating premenstrual syndrome. 26,2′ The use of vitamin E and garlic by men reflects their concern for cardiovascular disease. Such trends suggest that consumers are knowledgeable about the purported benefits of common supplements.

Multivitamins were used irrespective of gender, age and level of education and may be an appropriate tool by which DRI recommendations, promoting supplemental nutrients (e.g., folate), can be implemented. Developing effective strategies to provide supplemental nutrients to those with limited financial resources is important, although our data do not allow an evaluation of the frequency of supplement use by poorer households relative to others. Among low-income females using food banks in Toronto, 12% reported supplement use, well below our sample population’s 46%.28

Health care considerations

While regulations on NHPs are still being developed, over 40% of Canadians partake in supplement use, feeling it is a “low risk” behaviour despite the fact that many NHPs contain metabolically active components and high levels of potentially hazardous nutrients.” To date, only British Columbia has drafted bylaws to regulate the education and professional status of traditional Chinese medicine therapists in an attempt to regulate and integrate the use of NHPs.29 As supplement users were found to use multiple supplements, commonly taking >1 supplement and often >1 vitamin or mineral product, there is a risk of user-induced nutrient interactions or excessive nutrient intake as well as complications arising from herbal supplement interactions or effects. Dietary supplements sold in Canada, including vitamin/mineral and herbal products, contain levels of nutrients and herbal compounds that can lead to irreversible health outcomes such as sensory neuropathy (excessive pyridoxine), teratogenicity (vitamin A) and severe metabolic complications/death (ephedra/ma huang).8,27,30-36 Even with regulations, further information on consumer selfselection of NHPs, as well as on their properties, could better place healthcare professionals to ensure these products provide a health benefit while avoiding potential harm.

Copyright Canadian Public Health Association Nov/Dec 2002

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