Warnings about safety of supplements in eye health review called 'gratuitous' by experts

By Hank Schultz

- Last updated on GMT

Photo: iStock/Vladimir Arndt
Photo: iStock/Vladimir Arndt

Related tags Dietary supplement

A recent Cochrane Review article that looked at the effects of antioxidant supplements on AMD contained some warning statements about the safety of the products that dumbfounded experts in the field.

Gratuitous, thats the word Id use,​ said Jeffrey Blumberg, PhD, of Tufts University. Blumberg is the senior scientist at the Antioxidants Research Laboratory​ at the Medford, MA-based institution.

The review was a look at 19 studies​ that examined the effects on the progression of age-related macular degeneration of supplements that included carotenoids such as lutein and zeaxanthin and vitamins and minerals such as vitamin E and zinc. As far as the effects of the these ingredients for slowing the progression of AMD, the authors found very modest support at best, something that experts in the industry disagreed with​. But they also had something to say about the products’ safety, too. 

Vitamin supplements may have harmful effects,​ they wrote in their conclusions. Although vitamin supplements are generally regarded as safe, the studies included in this review did not provide good evidence as to safety as they were generally too small and adverse effects were reported inconsistently.

Non critical reference thrown in as an aside

For Blumberg, who has put in decades conducting and reviewing research in the field and is intimately acquainted with many of the studies the Cochrane authors reviewed, the left-field reference to safety was jarring to say the least.

Safety is barely even mentioned in the full review paper ​(which ran to more than 100 pages), and then in a very non critical way, and yet it ends up in the specific conclusions and recommendations,​ Blumberg told NutraIngredients-USA.

It was not a thoughtful analysis in regard to the evaluation of safety outcomes. Many of the studies they looked at in the review didnt include safety outcomes,​ he said.

Lack of education breeds misinformation

Rick Kingston, PharmD, is a clincal professor in the pharmacy school at the Unviversity of Minnesota. He is also the president of regulatory and scientific affairs at SafetyCall International​, which contracts with dietary supplement companies on adverse event reporting. He is well aware of the unfounded fears that are out there about supplements, and some of the misinformation that helps keep those fears alive, even among highly educated observers who could be expected to know better.

This supplement safety issue continues to crop up in otherwise prestigious publications where one wouldand shouldexpect a more objective view. I think the biggest issue is that education regarding the science and safety of natural medicines in the form of supplements is simply not taught in the majority of educational curriculum of mainstream academic health science institutions. Without that basic training I suspect many healthcare professionals fear the devil they dont know and accept the risks of the devil they do know (modern pharmaceuticals),​Kingston said.

I know students in my natural medicinals class at the University of Minnesota come out with a more balanced view as to how they should objectively evaluate supplement ingredients. Its unfortunate that more mainstream graduating healthcare professionals are not being exposed to such training,​ he said.

Why discourage the use of efficacious products?

Kingston said its was especially unfortunate for these kinds of statements to be associated with such a highly researched category of supplements. Carotenoids in connection to eye health and visual performance have been the subject of the very sorts of large-scale, longer term trials​ that critics of dietary supplement research say are often lacking in the field. And these trials have shown statistically significant benefits. 

There is always room for ongoing study but these kinds of generic and gratuitous comments regarding questions of supplement safety without any supporting evidence are very unfortunate, especially as it relates to these particular supplements. Not only are the phantom concerns unfounded but they taint the underlying message that there appears to be some benefit with these substances. I know the risks and morbidity associated with AMD. Why would we discourage patients from using potentially beneficial supplements for such a condition where there is no evidence of a safety issue?​ Kingston asked.

Lynda Doyle, senior VP of marketing for carotenoids supplier OmniActive Health Technologies​, echoed the concerns of Blumberg and Kingston.

We do not agree with the authors statements about the risks of multivitamins. Vitamins and minerals in general, have a place in maintaining the health and general well-being of people and current RDIs are established to meet daily requirements and prevent deficiencieswhether through the diet or supplementation. In moderation, supplements are able to augment that which might be lacking from the diet or lifestyle choices that impact the overall nutritional status of a person,​ she said.

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