We need an evidence-based approach to longevity and healthspan

Dr Brad Stanfield believes SGLT2 inhibitors will be first longevity drugs prescribed by clinicians.

As a practising medical doctor with a passion for longevity, Dr Brad Stanfield is perhaps best-known for his popular YouTube channel, where he discusses healthspan-related topics ranging from supplements to fasting. Over the past two years, the New Zealand-based clinician has spoken out on several subjects that he feels strongly about – including his concerns about the antioxidant resveratrol, much-hyped for its potential longevity benefits.

Longevity.Technology: While we regularly speak to the researchers and companies involved in the field of longevity science, we don’t hear as often from the clinicians and doctors who will ultimately prescribe longevity interventions to patients. We caught up with Stanfield to learn more about the aspects of longevity that excite him… and which ones don’t.

While at medical school, Stanfield came across other doctors who were interested in longevity, and this sparked his initial interest in the field. But it was Dr David Sinclair’s appearance on the Joe Rogan podcast that inspired him to start his own YouTube channel.

“It sounded like medicine was on the cusp of having all of these amazing treatments to hopefully slow down and even reverse aging,” says Stanfield. “I wanted to start my own channel because there were so many people talking about health and supplements, but I noticed a lot of them were extrapolating cell or mouse data. They weren’t focusing on what the human clinical evidence shows and trying to take a critical approach to the research instead of just headline grabbing.”

Addressing the need for human clinical data in longevity is the primary focus of Stanfield’s channel – what can people do and change today to improve their healthspan.

“When I first started my channel, there was a lot of hype around different supplements and molecules and whatnot,” he says. “But today it feels like there’s more healthy scepticism in this field, and I think people are focusing on what truly matters, such as diet, exercise, and sleep. People are now starting to realise that it’s the basics and the foundation that they need to do for their health, and I think that’s a positive thing.”

Supplements need more human evidence

On Stanfield’s channel, supplements are a key focus. While he himself takes several supplements (nicotinamide riboside, sulforaphane, fisetin and others) Stanfield believes that, although they are “interesting”, they don’t yet have a significant part to play in improving our longevity.

“People don’t like it when I say this, but, at the moment, supplements are probably only a 1% gain,” he says. “All of the other stuff is where the real longevity benefits are – diet, exercise, sleep, meditation – all those things come first, and then it’s about basic biomarkers, like a simple blood panel, cancer screening and so on.

“If someone is doing the right diet, exercise, sleep, they’ve got a purpose in life, they’ve got a good social network, and they’re doing okay financially, those are the things that will extend healthspan now.”

As someone on the clinical front line, Stanfield doesn’t believe that most medical doctors would consider prescribing or recommending longevity supplements to patients. There just isn’t enough evidence of their effect in humans (yet).

“In New Zealand, for example, there is a big push for preventative medicine, so we are encouraged as GPs to be as proactive as we can,” he says. “Our clinical guidelines get updated and changed all the time – it’s a good, robust way for high-quality research to come through and be acted upon. We go to conferences and listen to the specialists in the fields about new medications that are coming through.

“But most of the interventions that are talked about in the longevity field have limited human data. And the human data that is out there is often from underpowered trials that haven’t necessarily been run in a robust manner. That’s why a lot of longevity supplements aren’t often talked about by medical doctors.”.

This healthy scepticism is what led Stanfield to look deeper into the evidence supporting the longevity benefit of resveratrol, which has put him at odds with leaders in the field, including David Sinclair, who has long championed resveratrol’s benefits.

“The hope was that there was going to be treatment options based around resveratrol, that could hopefully extend healthspan and even lifespan,” says Stanfield. “A lot of money was poured into this research but, unfortunately, it didn’t pan out. There’s no evidence that resveratrol improves healthspan or lifespan – there’s no human data showing any benefit.”

SGLT2 inhibitors will be first longevity drugs

Despite his views on supplements, Stanfield believes that there are systems in place to allow longevity interventions to end up in clinical use, especially the Interventions Testing Program run by the US National Institute on Aging. He cites results seen in SGLT2 inhibitor Canagliflozin as an example.

“The Interventions Testing Program reported a median 14% lifespan extension in male mice with this medication,” says Stanfield. “That’s very interesting, but needs more work, and that work is being done in the clinical field.”

SGLT2 inhibitors are already being used to treat Type 2 diabetes, but Stanfield says clinical work is now indicating that these medications could also have an impact in heart failure, chronic kidney disease and weight loss.

“In terms of a so-called longevity medication, I think that SGLT2 inhibitors will be the first ones that will be prescribed and made widely available. That’s because they appear to provide significant protective effects for the kidneys. Our kidney function starts to decline from around the age of 30, so if we can use SGLT2 inhibitors to slow down or prevent that decline, that would be a powerful intervention. Of course, we’re waiting on the human data to come through, but there is a robust way of these things getting through to people.”

Stanfield is also optimistic about several other molecules studied by the ITP, including rapamycin, 17α-Estradiol, and NAD precursors, all of which have shown positive results in the program.

“There are quite a lot of things that are coming through that are very interesting, and that I’m excited to follow,” he says. “There’s a lot going on, and that’s why I still create videos because it still excites me.”

“Maybe in the future, there’s going to be something that can reverse that age, maybe not. But even if we can get a 10% or 20% improvement in healthspan, that would be massive, not only for people’s lives, but economically as well.”.

Photograph: Dr Brad Stanfield