Nutritional Supplements for Diabetes Sold on the Internet

Methods

Search Strategy

The web search was conducted in April 2012, to identify websites selling NSs for the treatment and prevention of diabetes mellitus. The research was performed using 3 of the main search engines commonly used to seek information, Google, Yahoo and Bing!.^[12] The key term used was "diabetes nutritional supplements". As shown in Figure 1, the first 30 occurrences on the 3 search engines were analysed to identify websites selling NSs. Sites were included if (a) they sold supplements directly to the consumer, (b) they did not require a password to obtain the ingredients, (c) they showed the complete list of ingredients and (d) they were in English. Sites were excluded if they (a) were broken links and (b) were not organised by disease category. Twenty-eight websites were identified as sales websites; 12 of these were mentioned in more than one search engine and were only considered once. All the websites identified in Yahoo were the same identified in Bing!. Six ones didn't fit the inclusion criteria. Only 10 sites suited our study purpose.

(Enlarge Image)

Figure 1.

Diagram selection of web sites selling diabetes nutritional supplements.

Under the "Diabetes" category we analysed the first nutritional supplement suggested by the website (the supplements were not shown in alphabetical order).

The content of each website was evaluated according to the main indications provided by the National Institute of Health Office of Dietary Supplements (NIH-ODS) on how to evaluate health information on the internet.^[13] In particular, we evaluated how easy it was to find the person responsible for the website, the indication of the health information source and a possible reviewer of it, the presence of bibliographical references supporting the NS, and the presence of the FDA disclaimer statement. Testimonials, medical indications, safety claims and side effects provided by the site were also recorded.

Literature Review

In order to analyse scientific evidence of the efficacy of these supplements, a PubMed search was carried out on ingredients shared by at least 3 NSs. The bibliographical search for the specific ingredient was carried out, in addition to the following key words defined using the MeSH Database on PubMed: "Diabetes Mellitus" [Mesh]. The search was limited to randomized controlled trials (RCTs), systematic reviews (SRs) and meta-analyses (MAs) studies conducted on humans in the last 10 years.

The authoritative fact sheets on NSs provided by the NIH-ODS and the references reported by the sales websites in relation to the ingredients selected in this study were also considered. The FDA website was also used as a resource.

The literature analysis focused on the findings regarding the efficacy of these ingredients in treating diabetes mellitus, the method of administration, the indications for specific diabetes-related diseases and the possible side effects.

Table 1. Characteristics of nutritional supplements sales websites included in the study
Company	URL*	Website location	Nutritional supplement	Health Professional contact suggested	FDA disclaimer†	Scientific references	Testimonials
Type II Free	https://www.typefreediabetes.com	USA-New York	Glucocin	No	No	No	No
Xtendlife	https://www.xtend-life.com	USA-Georgia	Diabet-Eze	Yes	No‡	Yes	Yes
ADW American Diabetes wholesale	https://www.americandiabeteswholesale.com	USA-Florida	Diachieve Sugar Defense	No	No	Yes	Yes
Green Turtle Bay Vitamin Company	https://www.energywave.com	USA-Winsconsin	Diabetiks	Yes	Yes	No	Yes
Native Remedies	https://www.nativeremedies.com	USA-Texas	Insulate Plus	No	No	Yes	Yes
Heart, Diabetes & Weight Loss	https://www.vagnini.com	USA-Texas	AGE Essential Defence	No	No	No	No
NutriVera Naturals	https://www.nutrivera.com	USA-Minnesota	Alpha Betic	Yes	Yes	No	No
Optimum Diabetics	https://www.optimumdiabetics.com	USA-Texas	Optimum Diabetics	Yes	Yes	No	Yes
Get Healthy Again	https://www.gethealthyagain.com	USA-Florida	Custom Elixir D	No	No	No	No
Nutrient Synergy, Inc.	https://www.nutrientsynergy.com	USA-Florida	Nepretin	Yes	No§	No	Yes

*latest access on 20th April 2012 †FDA disclaimer: "This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease" ‡the statement that the product is not a diabetes medication replacement is contained in the FAQ section. §the statement was not complete.

Table 2. Characteristics of references retrieved on the websites selling nutritional supplements
Nutritional supplement	Ingredient	N° of references	N° of relevant references*	Publication date of relevant references
Glucocin
	Biotin	19	2	1990
	Magnesium	26	2	1998
	Chromium	26	10	from 1987 to 2000
	Momordica c.	3	1	2007
	Gymnema s.	3	–	–
	Camellia s.	27	–	–
Diachieve
Sugar Defense	†	23	3	1997/1999/2000
Insulate Plus
	Chromium	2	1	1990
	Gymnema s.	1	–	–
	Vaccinium m.	2	1	1997

*studies carried out on humans and regarding diabetes, –The studies regarded the entire product and not the single ingredient

Table 3. Dosage recommended for nutritional supplements (NSs) offered by the companies online and dosage tested
Ingredient	N° of websites on which the dosage was specified/websites selling the relative NS	Dosage per day (mg) indicated in the website	Dosage tested (mg)	Reference
Alpha Lypoic Acid	1/6	600	300	Ansar et al., 2011 [14]
			600	de Oliveira, 2011 [15]
			600/1200/1800	Bartlett, 2008 [16]
			600/1200/1800	Lee, 2011 [17]
Gymnema sylvestre	1/6	2700	400	Leach, 2007 [18]
Magnesium	3/5	300 (2 websites)	365	Mooren, 2011[19]
Magnesium	3/5	768 (1 website)	291.6 – 745.2	Bartlett, 2008 [17]
Chromium	2/5	0.3	0.02 – 1	Bartlett, 2008 [16]
		0.66	0.04	Sharma, 2011[20]
			0.5	Kròl, 2011[21]
			0.5 – 1	Ali, 2011[22]
			1	Cefalu, 2010 [23]
Zinc	3/4	15	10	Shidfar et al., 2010 [24]
		54	30	Bartlett, 2008 [16]
		78	50	Hussain, 2006 [25]
Camellia sinensis	2/4	40	150 – 600	Neyestani, 2010 [26]
Camellia sinensis	2/4	1800	375 – 750	MacKenzie, 2007 [27]
Biotin	2/3	0.2	2	Albarracin, 2008 [28]
			2	Geohas, 2007 [29]
			5	Revilla-Monsalve, 2006 [30]
Momordica charantia	1/3	2700	1000	Ooi, 2010 [31]
Momordica charantia	1/3	2700	500–2000	Fuangchan, 2011[32]
Trigonella foenum-graecum	0/3	–	2800	Losso, 2009 [33]
Vaccinium myrtillus	1/3	100	–	–