Attention When Picking Supplements for Diabetes

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Nutritional supplements for diabetes may carry misleading information

September 5, 2013 / Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

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(dailyRx News) The number of diabetes patients who take nutritional supplements to control their blood sugar is increasing. But do supplements really help to improve diabetes? What are the main ingredients that are used in supplements for diabetes? How safe and regulated are they?

In a recent study, researchers examined the different nutritional supplements marketed for diabetes treatment or prevention that are available to buy on the internet.

These researchers found that some information provided by the websites selling the supplements could mislead the consumer into thinking that the advertised supplement is the answer for their diabetes. But there is a lack of scientific evidence to back up such claims, according to the researchers.

"Discuss taking any nutritional supplements with your doctor."

This study was conducted by Umberto Gelatti, MD, from the Department of Medical and Surgical Specialties, Radiological Sciences and Public Health at the University of Brescia in Italy, and colleagues.

Using Google, Yahoo and Bing, these researchers performed web searches for “Diabetes nutritional supplements.” They analyzed the first 30 results from each search engine. They then discarded websites if they were not sales websites, were not in English, were duplicates or they couldn’t access the website.

The following 10 nutritional supplements for diabetes were selected:

  • Glucocin 
  • Diabet-Eze 
  • Diachieve Sugar Defense 
  • Diabetiks 
  • Insulate Plus 
  • AGE Essential Defence 
  • Alpha Betic 
  • Optimum Diabetic 
  • Custom Elixir D 
  • Nepretin 

All the companies that sell these supplements are located in the US.

Nutritional supplements don’t require approval by the FDA to be sold. However, the FDA sets some general regulations. For example, it is required that supplements contain the following disclaimer: "This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease."

When the researchers looked at each nutritional supplement package, they found that only Diabetiks, Alpha Betic and Optimum Diabetics had the correct FDA disclaimer. Moreover, only half of the products suggested consulting a doctor.

Another FDA regulation states that the manufacturer name has to be clearly written on the packaging of a supplement. Manufacturers are responsible for the safety of the product, not the FDA. Results showed that the manufacturer was indicated in only three products out of the 10 examined.

The researchers also compiled a list of ingredients included in the 10 nutritional supplements. They found that a total of 71 different ingredients were being used. Of these ingredients, 42 were found in only one of the supplements, and 19 of the ingredients were found in two supplements.

The ingredient used the most in the 10 supplements was alpha lipoic acid, which was present in seven supplements. This finding shows that the diabetes supplements investigated were very different from one another.

The researchers focused on ingredients that were used in at least three supplements, and 10 of the 71 ingredients met the criteria. The most common ingredients included were the following:

  • Alpha lipoic acid, included in seven supplements
  • Gymnema sylvestre, included in six supplements
  • Chromium, included in six supplements
  • Magnesium, included in five supplements
  • Zinc, included in four supplements
  • Momordica charantia, included in four supplements
  • Camellia sinensis, included in four supplements
  • Biotin, included in three supplements
  • Trigonella foenum-grecum, included in three supplements
  • Vaccinium myrtillus, included in three supplements

Then, the researchers looked into existing scientific articles for evidence on the efficacy of each of the 10 ingredients.

Most of the existing studies focused on type 2 diabetes. Studies determined efficacy of the ingredient using two tests: the fasting glucose test (blood sugar levels after 8 hours without food) and the hemoglobin A1c, or HbA1c, test (a measure of average blood sugar levels over past three months).

When the fasting glucose test was used, and this measurement was compared between people taking and not taking the ingredient, the researchers found the following:

  • For alpha lipoic acid and gymnema sylvestre, one of four studies reported reduced blood sugar levels.
  • For magnesium, two of three studies reported reduced blood sugar levels.
  • For chromium, four of six studies reported reduced blood sugar levels.
  • For zinc, one of four studies reported reduced blood sugar levels.
  • For biotin and momordica charantia, one of three studies reported reduced blood sugar levels
  • For trigonella foenum-graecum, one of two studies reported reduced blood sugar levels.

When the hemoglobin A1c test was used, and this measurement was compared between people taking and not taking the ingredient, the researchers found the following:

  • For gymnema sylvestre and magnesium, one of two studies reported reduced HbA1c.
  • For chromium picolinate, one of four studies reported reduced HbA1c.
  • For zinc, one of two studies reported reduced HbA1c.
  • For biotin and trigonella foenum-graecum, one study reported reduced HbA1c.
  • For momordica charantia, one of two studies reported reduced HbA1c.

In summary, the results obtained from the scientific studies were not consistent. While some studies reported that a certain ingredient was effective in controlling blood sugar, other studies found no difference.

Few studies investigated the adverse effects of the ingredients. At most, two studies addressed the safety of alpha lipoic acid, camellia sinensis, biotin, momordica charantia and trigonella foenum-graecum.

The researchers also noticed that in some cases, the doses recommended on the supplement packages were higher than the doses used in the scientific studies.

There are other factors that remain unknown, such as the long-term effects and interactions with medications. This is important because diabetes is a chronic disease and people may be taking these supplements for a long time.

The consumption of nutritional supplements among the world population keeps increasing. The article reported that around 73 percent of the US adult population uses nutritional supplements, possibly because of their easy accessibility and marketing through the internet.

This article showed that many of the nutritional supplements for diabetes don't follow FDA regulations and don’t provide accurate information for the consumer, thus scientific research remains inconclusive on the effectiveness of their ingredients.

The researchers concluded that the handiness of supplements with disputable efficacy on diabetes and misleading information is a public health concern, since supplements may be interfering with the appropriate management and prevention of diabetes.

The researchers suggested that there is a need for public awareness on the use of nutritional supplements. The FDA website provides general tips for consumers on how to make informed decisions and evaluate nutritional supplements.

This study was published on August 26 in BMC Public Health. The authors had no disclosures to make.