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Issue #57 (July 2019)

From the Editor

Volume 1

In the NERD, we mainly cover studies that focus on the possible benefits of nutritional supplements, as opposed to their safety. One reason for this is because of our choice to report on research that has the highest chance of establishing causality in our deep dive articles. That means we focus mainly on clinical trials and meta-analyses of clinical trials. And most of the studies that fit this bill happen to be focused on potentially positive effects. Due to the way supplements are regulated in the U.S. and some other countries, clinical trials assessing safety aren’t mandated in order to market supplements. So, at the end of the day, there’s simply less strong safety evidence out there to cover.

However, this doesn’t mean that safety isn’t important. Far from it. In fact, I think it’s the most important thing to focus on concerning supplementation. That’s because while supplementation can be useful, it’s usually not essential, except in relatively rare cases (e.g., severe nutrient deficiency). If someone’s aiming to improve their general health through supplementation, then making sure the supplements they’re taking are actually safe should be top priority, since if the supplement causes harm, then it’s working directly against their goal!

While our hand is forced from focusing on supplement safety in our deep dives due to the relative paucity of strong evidence, we do try to highlight safety findings in the studies we cover when they’re reported. Also, we allow ourselves a little more flexibility in covering other things besides clinical trials and meta-analyses of clinical trials in our NERD Minis. We take advantage of this flexibility in this volume where we cover a recent study looking at the self-reported adverse effects of multi-ingredient pre-workout supplements.

I also have some flexibility to mention safety issues here that I’d like to take advantage of, so I’ll use it to briefly mention another safety-related study[1] that recently caught my interest. The study found some pretty serious supplement safety issues in children and young adults. Specifically, the researchers found that muscle building, weight loss, and energy supplements were about three times more likely than vitamins to have serious adverse effects reported in the U.S. Food and Drug Administration's Adverse Event Reporting System. The paper also reports that supplements for colon cleansing and sexual function had an increased risk of serious adverse effects compared to vitamins, too. They used vitamins as a baseline for comparison since they are the most commonly consumed supplement.

It’s impossible to estimate the absolute risk of these supplements using these data, since we can’t tell how many people took supplements in the time period the researchers examined. But the exact risk doesn’t matter too much in my opinion, since the adverse effects were pretty serious — they included death, disability, and hospitalization — and the benefits of many of these supplements are questionable.

Given this evidence, the questionable benefits, and the fact that the American Academy of Pediatrics cautions[2][3] against the use of performance enhancers and energy drinks, there’s good reason for younger people to think twice before taking these kinds of supplements.

Gregory Lopez, MA, PharmD
Editor-in-chief, Nutrition Examination Research Digest

Volume 2

I’ve been on a safety kick for my past few NERD intros. Since being concerned with supplement safety is a great habit to keep, I’d like to continue the trend for this volume by chatting about some recent news on vinpocetine.

Examine.com has a page on vinpocetine, but to save you a click, I’ll start off by covering some basics on it, then chat about some recent happenings.

Vinpocetine is a synthetic chemical, meaning that it’s not directly purified from a plant. However, it’s main precursor, vincamine, is — it’s an alkaloid derived from the periwinkle plant. Vinpocetine can also be synthesized from tabersonine, found in Voacanga seeds. Vinpocetine is actually regulated as a pharmaceutical drug[4] in parts of Europe, Russia, and China and used to treat stroke and cognitive impairment due to vascular disease and dementia.

It’s not completely clear why it can be useful for these conditions, since vinpocetine does a lot of things, although we’re not totally in the dark about its mechanism of action. It’s known[5] to improve blood circulation in the brains of people who have had strokes, and these changes in brain blood flow seem associated with improved cognitive outcomes. It also seems to improve [6]the brain’s oxygen and glucose uptake. Cognitive effects may be driven in part by vinpocetine’s influence[7] on neurotransmitter release due to its effect[8] on presynaptic sodium and calcium channels.

Vinpocetine’s effects in people with cognitive impairment, combined with considerations about its mechanism and some direct evidence[9] that it can influence cognition in healthy people has led to its use as an ingredient in dietary supplements in the United States, primarily as a nootropic and for “brain health”. It’s also marketed to increase energy and help with weight loss. The problem with that is that there’s doubt that it meets the definition of a dietary ingredient in the United States.

The FDA received a new dietary ingredient notification for vinpocetine back in 1997, and allowed it to be marketed as a dietary ingredient. But in 2016, it changed course, expressing doubts that vinpocetine actually met the definition of a dietary ingredient because it’s chemically synthesized from a plant, not an extract from a botanical source or a metabolite of something found in plants.

While the debate of the legal status of vinpocetine is important, the FDA released something even more important in June of 2019: they issued a warning that it may cause fetal harm or miscarriage based on evidence from the National Institutes of Health’s National Toxicology Program. They suggest that women who are pregnant, or who could potentially get pregnant, avoid any supplement with vinpocetine in it. They are also advising manufacturers to put warning labels on their products.

tl;dr: women who are or can become pregnant should avoid supplements with vinpocetine in it.

Gregory Lopez, MA, PharmD
Editor-in-chief, Nutrition Examination Research Digest

See other articles in Issue #57 (July 2019) of Study Deep Dives.