“Glyconutrients,” Mannatech, and Ambrotose: Marketing, Not Science 2

This doctor (Ben Carson) believes “glyconutrients” cured his prostate cancer. Researchers in the field of glycobiology think he is wrong. They don’t even accept the term “glyconutrients.”

It has been a long time since I first became aware of Mannatech, the multilevel marketing company that sells “glyconutrient” dietary supplements. After its claims were debunked and it lost a court case, it had dropped off my radar; but last month it came roaring back in the form of an email from a reader in South Africa. He said his in-laws had recently become Mannatech Sales Associates. Although the company can’t legally claim that their products cure any ailments, they continue to imply that their products give your body the tools it needs to cure itself. Company representatives and other advocates continue to claim in seminars and on the Internet that Ambrotose helps with a variety of conditions including MS, AIDS, cancer, lupus, colitis, diabetes, fibromyalgia, cystic fibrosis, ADHD, neuralgia, wound healing, and much more. There are even claims that it “cures” Down syndrome and even changes its characteristic facial features. My correspondent had done his own research and had concluded that Mannatech was marketing modern day snake oil with outrageous claims. But he was shocked that there was so little impartial information available about “glyconutrients.”

He is right: much of the available information about “glyconutrients” is from people who are trying to sell products; there isn’t much unbiased information available. Science-Based Medicine has not previously addressed “glyconutrients” or Mannatech except when Dr. Gorski recently wrote about presidential candidate Ben Carson, MD, shilling for Mannatech and claiming that Mannatech products had cured his prostate cancer. Let’s take a closer look at the science behind the claims for “glyconutrients.”

The science of “glyconutrients”

The very term “glyconutrients” is questionable. There is no accepted scientific definition. It is a marketing term coined by Mannatech to refer to eight sugars that they say are needed at the cellular level for optimum wellness: fucose, galactose, glucose, mannose, N-acetylgalactosamine, N-acetylglucosamine, N-acetylneuraminic acid, and xylose. They say you may not be receiving these beneficial sugars in the right amounts from the food you eat, so you will benefit from their supplement products. The Society for Glycobiology does not accept the term “glyconutrients.” It has this disclaimer on its website:

The Society for Glycobiology is a scholarly society devoted to furthering knowledge of the functions of sugar molecules in biology and medicine. As world leaders in academic glycobiology, the Society’s members may receive requests for information about health benefits of nutritional supplements, including but not limited to so-called glyconutrients, glyconutritionals, or other similarly named products.

The Society does not endorse use of these or other nutritional supplements, and is not associated with any manufacturer or supplier of “glyconutrients”. The Society urges persons having questions regarding nutritional supplements to consult a physician before initiating use of any nutritional supplement claiming to enhance health or treat disease.

A PubMed clinical query search for “glyconutrients” brings up a scant 5 articles, the most pertinent being a devastating critique titled “A ‘Glyconutrient Sham’” by Schnaar and Freeze in the journal Glycobiology. The full text is available online. They deplore the perversion of glycobiology science for commercial purposes, citing the false claims of Mannatech. They are concerned that these commercial claims may adversely impact respect for legitimate research in glycobiology. They point out that three Nobel laureates have taken action to stop Mannatech from using their names to promote “glyconutrient” sales.

They say:

we hope to maintain a bright line between legitimate glycobiology research, including research into the potential of dietary glycans to be of health benefit, and what has become a vigorous marketing campaign to sell certain mixtures of plant polysaccharides as health products in the absence of controlled clinical studies to support their efficacy.

They point out that humans biosynthesize the different monosaccharides the body needs from common dietary precursors. They question whether dietary glycans are required for or significantly enhance glycosylation. They suggest that the components of Ambrotose can’t even be effectively digested, since the body lacks the necessary enzymes.

They reference the patent for Ambrotose, which includes a long list of disorders and diseases “… treated by administration of glyconutrients… (alone or in combination with other nutraceuticals).” The list of treated diseases is breathtaking: aging, stroke, multiple sclerosis, ALS, muscular dystrophy, cerebral palsy, macular degeneration, Down syndrome, immune deficiency, Tay–Sachs, Huntington’s, Alzheimer’s, Parkinson’s, spinal cord injury, Crohn’s, Tourette’s, lupus, rheumatoid arthritis, alcoholism, atherosclerosis, asthma, allergy, silicon breast implant, agent orange, Gulf War syndrome, hepatitis, influenza, common cold, AIDS, cancer, and poor athletic performance (among others).

They point out that the claims allowed by the patent office do not establish that the product works. The patent applicant is claiming that the product can be used to treat those disorders, not that it has been proven to have a therapeutic effect.

They review the evidence for “the value to human health of ingesting glycans – particularly the plant polysaccharides larch bark arabinogalactan, aloe vera glucomannan, and plant gums” and find “no convincing support for human therapeutic or health claims of Ambrotose® Complex or its components.”

They show how “Those who claim to speak for the glyconutrient industry often challenge the basic principles of scientific inquiry.” They say, “As scientists, it is also our mandate to impress on the public the importance of rigorous unbiased studies to distinguish biomedical facts from marketing schemes.”

The scientific evidence for Ambrotose

Whatever the basic science says about the biochemical role of these sugars, what potential customers need to know is whether there is any scientific evidence that the product Ambrotose has clinical benefits. A PubMed search for “Ambrotose” yields these 6 articles that are far from convincing:

  1. A small placebo-controlled study reported a statistically significant improvement in recognition and working memory performance in middle-aged adults under conditions of mental fatigue.
  2. An open-label study found significant changes in serum protein N-glycosylation in healthy adults but noted that biological significance remains to be determined.
  3. A double-blind crossover study found increased resting blood antioxidant capacity and “may enhance post exercise antioxidant capacity. However, no statistically detected difference is observed in resting or exercise-induced oxidative stress biomarkers, in quality of life, or in GXT time to exhaustion.” They measured antioxidant capacity by ORAC, a measure that was rejected by the USDA because of mounting evidence that it had no relevance to the effects of specific bioactive compounds, including polyphenols, on human health.
  4. A forced titration open label study was designed to determine the optimal dose; it also depended on ORAC scores and the authors warned that their results should not be over-interpreted, that it was a preliminary phase 1 and 2 trial, subject to limitations and potential bias, and that potential benefits would have to be confirmed by a phase 3 randomized controlled trial.
  5. A study on rats with induced colitis. ‘Nuff said.
  6. An opinion piece asking “Doctor, should I supplement my diet with Ambrotose?” that states there’s no good evidence to back any of its therapeutic claims.

The company’s own magazine even admitted that there were no double-blind, placebo-controlled studies of the type used by drug companies establishing that its products work.

Mannatech products

The company website offers a multitude of products for integrative health, targeted health, weight, fitness, skincare, and home living; but their flagship product is Ambrotose. Here are the claims for Ambrotose:

  • May enhance recall and recognition memory.
  • May improve mood and decrease irritability.
  • Supports your immune system as well as proper organ function.
  • Helps support proper digestive system function.
  • Promotes gastrointestinal health.
  • Supports cell-to-cell communication through a blend of specific plant saccharides called Glyconutrients.

The website includes the required FDA disclaimer (aka the Quack Miranda Warning). Mannatech can’t legally claim to treat or cure any disease, but they manage to do so indirectly. YouTube abounds with testimonials.


One typical YouTube video reports miraculous cures of cancer, autoimmune disease, allergies (symptoms resolved in 3 hours!), hormone disorders, arthritis, bursitis, plantar fasciitis, autism, rashes, diarrhea, constipation, seizures, atopic dermatitis, lymphangioma, diabetic neuropathy. Birthmarks resolve, patients report improved sleep, improved hair growth, etc.

Other videos make claims for a variety of other conditions. There are even videos claiming that glyconutrients “completely healed” people with Down syndrome.

Legal actions

In 2009 Mannatech and its founder agreed to pay $7 million to resolve a complaint by the Attorney General of Texas. It agreed to monitor sales associates’ statements about its products and to not advertise or otherwise claim that its products can cure, treat, mitigate or prevent disease.

Mannatech has also been sued by its investors.

An Australian doctor lost his license for selling up to $250 a month of Mannatech products to patients with hemochromatosis, cancer, infertility, and seizures and misrepresenting the products as effective for those conditions.

Conclusion: Marketing, not science

There is no credible evidence behind the claims for “glyconutrients.” “Glyconutrients” is not even an accepted scientific category. Mannatech is marketing a myth.

This article was originally published in the Science-Based Medicine Blog.

Dr. Hall is a contributing editor to both Skeptic magazine and the Skeptical Inquirer. She is a weekly contributor to the Science-Based Medicine Blog and is one of its editors. She has also contributed to Quackwatch and to a number of other respected journals and publications. She is the author of Women Aren’t Supposed to Fly: The Memoirs of a Female Flight Surgeon and co-author of the textbook, Consumer Health: A Guide to Intelligent Decisions.

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