Nutrition myth busting: Photo of pink and white boxing gloves against a polished concrete background.

Something I take seriously, whether I’m talking one-on-one with a clients, writing a newspaper article, or writing a post or this blog, is myth-busting. There is a lot of misinformation (read: myths) about nutrition and health out there, and there’s a lot of information that’s presented in the type of science-speak that sounds totally legit unless you happen to have training in the sciences or at least have a reliable source to say, “OK, hold the phone, here!”

I hope I’m one of those sources.

I want my clients and readers to be safe. I don’t want you to be spending your time and money chasing magic bullets that aren’t so magic after all. I want you all to be informed consumers of not just information, but of foods, supplements, or practices/protocols (for lack of a better word).

I take nutrition myth-busting seriously. Photo is of a white coffee mug with black lettering that says "What good shall I do this day?"
Interpreting what science actually says

Last week, I wrote an article for The Washington Post on supplements that purport to boost levels of NAD (also known as NAD+ and NADH in the body). In case the article is behind a pay wall for you (depends on how many WaPo articles you’ve already read for free), I’ll give you a thumbnail sketch:

  • It’s well established that NAD levels drop in the body as we age, in part because we produce less of it, and in part because our body’s demand for it increases. So we’re making less, and using more.
  • It’s also well established that lower NAD levels play a role in the increased risk of developing chronic diseases that comes with age.
  • The intriguing idea is that increasing NAD levels by supplementing with “NAD precursors” will reduce chronic disease risk, essentially leading to healthier aging, and possibly greater longevity. The two main NAD precursors being studied are NR and NMN.
  • Both NR and NMN have had promising results in MOUSE studies, but NR has been somewhat disappointing in human studies. Results of a randomized clinical trial on NMN will be released next year (I interviewed the researcher, and he couldn’t tell me much pending publication, but he hinted that the results are promising). In humans, NR has been able to increase NAD levels, but there is so far no evidence that this is improving health.
  • I ended the article with the bottom line advice that people can take NAD-boosting supplements if they want (hey, we’re all adults), but be aware that there is no human evidence at this time that forcing NAD levels up will reverse the effects of naturally falling NAD levels. In other words, it’s your money, but I myself will wait to see what future research turns up.
I take nutrition myth-busting seriously. Photo is a blurry image of a woman with her fist extended towards the camera (in focus), with a gold ring that says "I am bad ass."
A little reminder that I can’t make everyone happy

Well, my article displeased one of the companies producing NAD-boosting supplements, and their PR rep reached out and asked me to chance a bunch of information in the article (this did not happen, because my article is accurate).

The rep sent me a multi-point email, and I sent an email back, responding to each point. I was actually astonished at some of their arguments, because they perfectly illustrated why I wrote this article. I’m including edited version of our “email discussion” below (I edited out anything that identifies the company or its product, as well as some other extraneous wording). I think this offers an excellent example of some of the “science-speak” that can lead everyday people to think that the science behind a food, a supplement, a drug or an idea is more robust than it really is. I’ve added emphasis on key statements, and added some extra notes for clarity where appropriate.

Nutrition myth busting. Overhead photo of two open laptops, back-to-back, along with a rustic blue plate with some heart-shaped cookies and a long handled-spoon, and an open hard-bound notebook.
The conversation…of sorts

The Rep: We don’t know if increasing NAD+ levels will impact the human aging process but clinical research certainly hasn’t demonstrated that it won’t. Currently, [company] has four ongoing clinical trials to evaluate [the product’s] effects.

Me: The burden of proof rests on whether something WILL work, not that it WON’T. It’s fantastic that clinical research is ongoing, and I look forward to seeing what comes of it, but the current state of the science is the state of the science, and there are many examples of supplements or other therapies that look promising, only to not pan out. 

The Rep: Our website states that [product] is designed to increase NAD+ levels…which supports cellular health. We do not claim that [product] promises longevity or healthy longevity.

Me: While your site does not make blatant claims that NAD-boosting supplements promise health and healthy longevity (unlike some other sites), anyone reading the marketing copy on [company’s] website would come away with the clear impression that it fights aging and improves health, ergo longevity and healthy longevity.

The Rep: [information about product] is central to our hypothesis that [product] may have the potential to support long-term health. Our study demonstrated that NAD+ levels increased [by amount]. Since we claim that [product] is designed to increase NAD+ levels, this was an important first step in demonstrating its efficacy. Again, the trial showed that [product] is effective at increasing NAD+ levels in humans and was conducted as any pharmaceutical trial would be—double-blind, randomized, and placebo-controlled.

Me: Again, it’s wonderful that you are able to demonstrate efficacy with some intermediate endpoints, but most consumers don’t care (or shouldn’t care) about simply increasing NAD+ levels…they care if raising NAD+ levels will result in hard clinical endpoints, such as risk of chronic disease. You also said, “central to our hypothesis that [product] may have the potential to support long-term health.” A hypothesis is not evidence; it is a starting point for conducting research and gathering evidence. No one should make health decisions based on a hypothesis—a hypothesis is a question, not an answer.

The Rep: “Because they are dietary supplements, not pharmaceutical drugs, they’re not subject to oversight by the Food and Drug Administration, and their manufacturers do not have to prove safety and efficacy.” This is untrue—while there is no FDA approval for dietary supplements, that does not mean that the industry is unregulated. The FDA issues guidance that dietary supplement manufacturers must follow, and the responsibility of adhering to the guidance falls on the manufacturers. Furthermore, [company] clinically tests its products for safety and efficacy. Every lot of [product] is third party tested for purity and quality. [Product] is NSF Certified for Sport, which means that NSF International tests every lot of [product] to confirm its purity and quality. 

Image of the official seals of supplement 3rd party testing: NSF, USP and Consumer Labs

[Note from me: I do recommend looking for seals from third-party testers. The three best are NSF, USP and Consumer Labs, and their official seals are in the image above. However, these labs test supplements to make sure they contain only the ingredients on the label, at the stated doses/potency, not that they work for any specified purpose. The NSF Certified for Sport program makes sure tested supplements don’t contain substances like steroids and pharmaceutical drugs.]

Me: Placing responsibility on manufacturers to self-regulate is not the same thing as being regulated. Conflating the two is a tiresome and overused argument, particularly because most consumers think supplements are regulated by the FDA and that any claims on the label have been approved by the FDA. While some supplement companies are absolutely responsible, others are not. And even if this article was about [company] specifically, which it is not, purity and quality are not measures of efficacy in achieving desired health outcomes.

Nutrition myth busting can be hard work. Photo of a woman laying in bed under a white comforter, holding a pair of eyeglasses, with her face mostly covered by a pillow.
Now, let’s sum this all up

The photo above is how I feel some mornings after I’ve written an article that butts heads with people’s beliefs about a food, as supplement, or an idea.

I work hard to not just breeze through the research literature picking up a study here and there, but to really dive in and make sense of what the overall research is saying, and what the consensus (or lack of consensus) is for now, knowing that on certain topics, that consensus might change as more research is done. That’s how it’s done—it’s not flip-flopping, it’s “This is what we know RIGHT NOW, and there’s stuff we don’t know, and when we discover answers to our open questions, that might change what we know at the moment. It might yield the answers we are anticipating, but it might yield totally different answers.”

Science might seem black and white, and some aspects of it absolutely are, but other aspects of it—especially in nutrition science, it seems—are very much in the gray. And that may be frustrating, but really, it’s OK. Make the best decisions for yourself that you can, and remember that lack of proof that something works is NOT the same thing as “Well, there’s no proof that it DOESN’T work.”


Carrie Dennett, MPH, RDN, is a Pacific Northwest-based registered dietitian nutritionist, freelance writer, intuitive eating counselor, author, and speaker. Her superpowers include busting nutrition myths and empowering women to feel better in their bodies and make food choices that support pleasure, nutrition and health. This post is for informational purposes only and does not constitute individualized nutrition or medical advice.

Seeking 1-on-1 nutrition counseling? Carrie offers a 6-month Food & Body program (intuitive eating, body image, mindfulness, self-compassion) and a 4-month IBS management program (low-FODMAP diet coaching with an emphasis on increasing food freedom). Visit the links to learn more and book a free intro call to see if the program is a good fit, and if we’re a good fit!

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