Some medications, such as statins, have been shown to protect brain health in scientific studies. Photo / Getty Images
The new shingles vaccine could help prevent cognitive decline, while statins and weight loss drugs may have similar protective effects.
At times, getting older can feel like a never-ending list of health check-ups. Vaccines you’re now eligible for, screenings to arrange, and a firm suggestion from your GP to begin a new course of medication.
We’re often warned about the long-term effects of certain drugs, but there are some midlife jabs or pills which appear to have hidden protective qualities, especially for the brain.
Take shingles vaccines for instance. A new study from Stanford University published in the renowned journal Nature, has discovered that being vaccinated in mid to later life against this painful viral rash prevents one in five new dementia cases over the next seven years, based on the examination of electronic health records.
The findings have caused such a stir that Dr Pascal Geldsetzer, the Stanford epidemiologist behind the study, told The Telegraph that he’s now seeking to raise funds from private foundations and philanthropists to conclusively test whether shingles vaccination can prevent cognitive decline in a clinical trial. “This is what we need to really convince the public health and medical community,” he says.
So why might a shingles jab be protecting the brain, and what are the other midlife immunisations and medications that seem to do the same?
Geldsetzer isn’t the only person to have uncovered evidence that shingles jabs might help shield the brain from dementia. Last year, another study found that the Shingrix vaccine, leads to a 17% reduced risk of dementia compared with older shingles vaccines.
While the benefits appear to be very real, scientists are still attempting to figure out exactly what’s going on. In recent years, suggestions of an infectious origin to Alzheimer’s disease have been steadily gaining traction and Geldsetzer says it’s plausible that the varicella-zoster virus – the virus behind shingles which also causes chickenpox in children and subsequently lies dormant in your nervous system for decades – could be reactivating as our immune systems weaken with age, with damaging consequences for the brain.
“There is suggestive evidence for the role of this virus in both vascular dementia and Alzheimer’s disease,” he says.
Geldsetzer’s research has thrown up an additional finding – the protective effect of shingles vaccination seems to be much greater in women compared with men.
“This could be due to sex differences in the immune response, with women on average having higher antibody responses to vaccination,” Geldsetzer suggests. “But it could also be the way in which dementia develops. We know that both shingles and dementia are more common in women than men.”
Statins are not the most popular of drugs, with people often voicing concerns about developing muscle and joint pain, but a major new study from South Korea has indicated an additional motivation to take them.
Based on health data from more than 570,000 Koreans, it showed that the cholesterol-lowering drugs reduced dementia risk by 13%, even in people with relatively low levels of LDL or “bad” cholesterol.
According to Dr Francesco Tamagnini, a dementia expert at the University of Reading, this may point to an emerging theory which could be linked to many cases of Alzheimer’s disease, the most common form of dementia. Called “the lipid invasion model” of Alzheimer’s, the idea is that the blood-brain barrier, the layer of cells which separate the brain from the circulation, becomes more permeable with age. This may be a consequence of a lifetime’s excessive drinking for example, or repeated head traumas incurred through sport or accidents.
This increased permeability allows LDL cholesterol molecules to pass over from the blood into the brain, instigating cell damage. “The brain has zero tolerance for LDL,” says Tamagnini. “The brain contains a lot of cholesterol, but it’s mainly the high density lipoprotein (HDL) cholesterol particles which are smaller. But if the larger LDL particles get in, that disrupts neuronal function. So this is an idea for why drugs like statins, which reduce the amount of LDL in the blood, will lower risk.”
If you’re a regular Viagra user, it could be doing far more than just boosting your erections. Last summer, a new study revealed that Viagra can increase blood flow in both large and small blood vessels in the brain, as measured through ultrasound and MRI scans, and it appears to lower blood vessel resistance, something which contributes to the development of vascular dementia.
“It could be beneficial through reversing the small blood vessel dysfunction that occurs with age and is the most common cause of vascular dementia,” says Alastair Webb, a NHS consultant neurologist who led the study and a researcher at Imperial College London. “By dilating smaller blood vessels, it could also help to reduce the stress on big blood vessels and reverse their increasing stiffness [with age].”
Erectile dysfunction drugs may even offer wider benefits for other dementias. A major Phase 3 clinical trial called POLARIS-AD is currently testing a drug called AR1001 in patients with early Alzheimer’s disease. Made by a company called AriBio, the drug is currently approved in South Korea for erectile dysfunction.
While blood vessel problems are also thought to be involved in Alzheimer’s disease, Tamagnini says that erectile dysfunction drugs can also increase production of a powerful hormone called nitric oxide.
“This is actually involved in the brain in memory consolidation,” he says. “If I had to bet a pint on why Viagra and these other drugs can lower risk of dementia, I would put it on nitric oxide, and that somehow promotes the formation of new memories.”
Could semaglutide be the wonder drug of the decade? As well as being a potentially game-changing weight loss medication, there are some very real suggestions that semaglutide – marketed as Ozempic for Type 2 diabetes and Wegovy for obesity – could help lower risk of Alzheimer’s disease.
The hype stems from two remarkable studies released last summer. The first found that diabetes patients taking semaglutide had a much lower risk of Alzheimer’s and other forms of dementia compared with those on a different diabetes drug called sitgliptin. The second found that Alzheimer’s patients who received daily injections of liraglutide – a similar drug to semaglutide which also mimics the GLP-1 gut hormone – over the course of a year, had 50% less brain shrinkage than those receiving a placebo.
According to Imperial College London neuroscience professor Paul Edison, the brain-protective effects of semaglutide and other GLP-1 drugs are about more than just weight loss. Edison explains that there are multiple cell types in the brain to which these drugs are capable of binding, and animal studies suggest that they’re capable of removing toxic proteins and stimulating neurons to repair themselves.
“We think it’s quite a neuroprotective drug,” says Edison. “It seems to activate different cascades of enzymes, and that reduces inflammation and eventually increases memory.”
We should soon have even more concrete evidence. Danish pharmaceutical company Novo Nordisk has initiated two Phase 3 studies, called evoke and evoke+, which have been running across 40 countries for more than three years, to see whether semaglutide has a positive effect on early Alzheimer’s disease. Results are expected next year.
It turns out that shingles is not the only vaccine which could make a difference. A study which saw scientists mine health data from more than 130 million individuals in the search for drugs with dementia-protecting qualities, highlighted the BCG vaccine for tuberculosis as a possible way of staving off cognitive decline.
However, Dr Ben Underwood, a researcher in old age psychiatry at the University of Cambridge who authored the study, says that he’s not convinced that there’s a direct line between the tuberculosis bacterium and dementia.
Instead, he suspects that the vaccine, which was first used medically in 1921 and most people are eligible to receive on the NHS, is having a wider immune-boosting effect.
“Maybe there’s a more general effect of vaccination which gears up your immune system and gives you some more protection,” says Underwood.
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