Change is Difficult

How I think about supplements that make health claims.

Dec 27, 2024

“Improves memory!”

“Reduces inflammation and supports brain health!”

It is tempting to believe that we can influence our bodies’ function by supplementing some molecule that is a participant in the biochemical processes, by taking some other compound that is not quite a drug but which claims to do good things with little or no risk, or by undertaking a trending lifestyle/behavior change, a “biohack,” targeted at influencing our physiology. Why not? Many of these strategies are presented with a good simple mechanistic story of how they work. For some, scientific-looking charts about experiments in test tubes, in mice, or even in human research subjects make it even more believable that the intervention will actually have the desired effect. But the truth is that most treatments don’t actually obey the simple story, and if they are properly tested they often prove not to be effective, or safe. Where human physiology is concerned, change can be hard.

If genes and proteins and cells follow predictable laws of physics and chemistry then why is it so difficult to develop effective treatments to control or modulate the way the whole human organism operates? One obstacle is that in mammals, the functioning of our organ systems is generally influenced not by one single control mechanism, but by a set of balanced forces evolved to keep important parameters under tight control within a very narrow range. In physiology, this principle is called homeostasis, and for many of our most important internal conditions, it is incredibly effective.

If someone you care about presents concerns about memory loss, cognitive dysfunction, or other problems of the brain, it will be difficult to ignore the advertisements, media stories, and testimonials from friends recommending a supplement. One of the most common ones sold for brain health, extracted from the leaf of the gingko biloba tree, is often claimed to improve cerebral (brain) blood flow and brain function. Sales of gingko biloba products are reported to be around $10 billion annually.

Blood flow to the brain is obviously important. More than other organs, the brain is quite sensitive to excessive or too little blood flow. Even brief or mild disruptions of the flow can cause problems. We have evolved systems that maintain the rate flow steady in healthy people, even when challenged by major changes in blood pressure. Together the function of these systems is called “autoregulation,” a form of homeostasis. It integrates several different forces acting to constrict or to dilate certain blood vessels in the brain, responding to the metabolic needs of each brain region, to the blood pressure itself, and to the overall state of the autonomic nervous system, the balance of “fight or flight” vs. “rest and digest.” MRI or nuclear functional brain imaging can even show researchers which part of the brain is activated by different aspects of a brain task; blood flow increases in one region when the subject in the scanner reads words, and in another region when the subject hears the words. Overall brain blood flow decreases during deep sleep, and increases on waking.

There are plenty of things that cause your blood pressure to go up or down quite a lot. Dehydration, pain, exercise, and many drugs can increase or decrease the blood pressure, yet the rate of blood flow to the brain stays under control. When cerebral autoregulation is disrupted, for example by traumatic brain injury, the consequences can be devastating. So if gingko biloba salespeople hope their product works and has a meaningful impact on increasing brain blood flow, with only good and no bad consequences, then all of the mechanisms of cerebral autoregulation stand ready to counteract the supplement or to interfere with its results.

If a supplement maker wanted some good-looking older people for their marketing, it would be hard to find a more attractive crowd than the participants in masters athletics! Generally fit-looking and confident in their streamlined outfits, the runners, jumpers, and throwers competing at the national level in my age group (60-64) certainly appear healthier than most of our peers. Many of the youngsters, the 35 year olds, look like they could still run for the Georgia Bulldogs or the Florida Gators. Most remarkable are the 80, 85, 90 year olds and older who show up with strong muscles and a ready-to-compete attitude — sprinting, pole vaulting, and hurdling with joy. At recent masters track and field competitions, another specific supplement marketed for brain health was promoted with their sponsorship on signs around the track and on the racing bibs we pinned to our shirts. A one month supply of this supplement retails for $50-100, with total sales reported to be hundreds of millions of dollars per year. The company has claimed in its marketing that the supplement improves memory, and improves brain function in aging. “Clinically shown” was part of many of their claims. We masters athletes provided thousands of photo impressions of the brand.

A careful examination of the scientific evidence, however, will not uncover any high-quality studies showing the impact of the product on human memory. The Federal Trade Commission sued the maker over their claims. A jury found that the claims were not supported by scientific evidence, and the federal court recently ordered the maker to stop making the unsubstantiated clinical claims.

I believe in your right to try things. But I don’t want to be part of selling you supplements telling important false stories about your health. So when I pinned my number onto my shirt, I folded over the bib to hide the logo of the supplement maker. A couple of my friends noticed; most didn’t. Michael Jordan gets paid billions to wear Nike logos, but as much as I would love to Be Like Mike, not even the fastest masters athletes have endorsement deals. That’s fine, really, but as a physician-scientist who cares about you, I chose not to give away my endorsement for free, especially for a supplement that is all marketing and false claims, and very little substance.

What do you think? How do you decide what product claims to believe? Hit the comments below! These are personal choices, but we can all use some help when it comes to thinking about our own health.