We all know heart health matters - but what if the same habits that keep your heart strong could also protect your brain? A new study reveals a link between cardiovascular health and lower levels of neurofilament light (NfL), a key biomarker of brain cell damage for Huntington’s disease (HD) research. So what does this mean for people with HD? Let’s dig into what HD families can take away from this new study that shows what’s good for your heart, is also good for your brain.

Heart Health and Brain Biomarkers

This study focused on the American Heart Association’s Life’s Simple 7, a set of lifestyle and health factors that promote heart health. The researchers aimed to determine whether people who follow these guidelines also show biological signs of better brain health.

The Life’s Simple 7 factors include:

• Eating a healthy diet
• Engaging in regular exercise
• Maintaining a normal body mass index (BMI)
• Not smoking
• Managing blood pressure
• Controlling cholesterol levels
• Regulating blood sugar levels

The researchers analyzed data from the Chicago Health and Aging Project (CHAP), a long-term study tracking the health of older Black and White adults from 1993 to 2012. A 19 year study provides a stellar dataset! Specifically, they focused on more than 1,000 participants aged 65 and older to see if those who scored higher on cardiovascular health also showed healthier brain biomarkers.

To assess brain health, the researchers looked at two important blood-based biomarkers, neurofilament light, or NfL, and total tau, or t-tau.

NfL as a Key Brain Biomarker

NfL is a protein that is released when nerve cells are damaged. So, higher levels suggest there is more neuronal damage. In neurodegenerative diseases like HD, as symptoms progress and brain cells are lost to the disease, levels of NfL rise. Because of this, NfL is used as a biomarker in many brain diseases and is gaining a lot of traction in HD research as more studies suggest that it’s strongly connected to the progression and severity of disease.

Perhaps most importantly, some of the newest research around NfL suggests that changes in the level of this protein can be detected before symptoms even start, making it an incredibly sensitive, and valuable, tool for tracking not only disease progression, but also the effectiveness of drugs. That last part is critical as the field moves toward testing drugs earlier, in groups of people before they even start showing signs and symptoms of HD.

So what happened in this new study when they looked at NfL levels in people with higher and lower cardiovascular health as they aged? The study’s findings were quite striking.

“Participants with higher cardiovascular health scores had lower NfL levels, suggesting that they had less neuronal damage. And we’re not talking just slightly, the numbers were incredibly impressive! ”

Connecting Heart and Brain Health

Participants with higher cardiovascular health scores had lower NfL levels, suggesting that they had less neuronal damage. And we’re not talking just slightly, the numbers were incredibly impressive!

For every 1-point increase in cardiovascular health score, participants had 3.5% lower NfL levels. Those with the highest heart health scores had nearly 19% lower NfL levels than those with the lowest scores. In other words, better heart health seemed to be linked to healthier brain cells!

These results suggest that actively working on your heart health, whether it’s through diet changes, incorporating more exercise, or effectively managing risk factors like blood pressure, could have a tangible impact on reducing a key marker of damage to your brain cells. So taking care of your heart could get you a brain benefit as a side effect.

The Long-Term Impact

The researchers didn’t just look at one snapshot in time. They followed over 800 of the study’s participants for a decade to see how NfL levels changed over time. What they found was that NfL levels naturally increased with age in all participants. However, those with better cardiovascular health had a slower rate of increase.

The effect of improved cardiovascular health was compelling - participants with low cardiovascular health scores saw an annual increase of 7.1% in NfL, while those with high scores had a lower increase of 5.2% per year. Over a 10 year timeframe, that really adds up!

The take home message here is that maintaining good cardiovascular health through heart-healthy habits over the long term could actually help slow down brain aging over time.

What About T-Tau?

This study also looked at another biomarker from people’s blood - total tau, or t-tau. T-tau is a protein that has increased levels in neurodegenerative diseases, particularly Alzheimer’s.

Interestingly, the study did not find a significant link between cardiovascular health and t-tau levels. This suggests that while heart health may play a role in reducing neuronal damage (as measured by NfL), it may not directly impact the processes that lead to tau-related neurodegeneration.

Why Are NfL and T-Tau Different?

While this study can’t say for sure why heart health plays a role in NfL levels as people age, but not t-tau levels, they did offer some possible explanations.

One thought is that NfL might be more directly influenced by vascular factors, things like blood flow and the health of blood vessels in the brain. Since the health of blood vessels, including those that run through our brain, are directly impacted by cardiovascular health, this could explain differences in NfL levels. Less healthy brain blood vessels could create a less supportive environment for our neurons, causing them damage.

However t-tau is thought to be more closely related to the actual clumping of tau proteins and the formation of neurofibrillary tangles, which are a hallmark of Alzheimer’s and other tau-related diseases, but not general brain health like NfL. So it could be that the biological pathways affected by cardiovascular health don’t have a major effect on driving tau protein accumulation.

It does seem clear though that the relationship between heart health and brain health is complex, and there are probably different biological processes at play.

“These results suggest that actively working on your heart health, whether it’s through diet changes, incorporating more exercise, or effectively managing risk factors like blood pressure, could have a tangible impact on reducing a key marker of damage to your brain cells. ”

The Effect Across Different Groups

The researchers also explored whether these connections varied across different populations. They found that the link between better cardiovascular health and lower NfL levels was seen in both men and women and across both Black and White participants. So sex and ethnic background didn’t seem to influence the association between heart and brain health.

Another group they specifically looked at was people who carry the APOE4 gene, which is a well-known genetic risk factor for Alzheimer’s disease. In this group, they found an even stronger association between better cardiovascular health and lower NfL levels. This could be an important finding for people who know they have this genetic predisposition.

A possible interpretation here is that people who are already at a higher risk for Alzheimer’s might see an even bigger benefit from taking care of their heart. While it’s tempting to speculate the same may be true for HD because of some similar mechanisms shared by the two diseases, the effect in HD wasn’t specifically examined in this study.

When they looked at people who already had some form of cardiovascular disease at the start of the study, the connection was less clear. They think this means that the largest benefit in brain health, as measured by NfL, may be gained before heart problems arise, meaning the biggest benefits might come from prevention and long-term healthy heart habits rather than treatment.

The Big Picture: Happy Heart, Happy Head

The study highlights that maintaining good cardiovascular health might help protect against brain aging and neurodegeneration. This adds to growing evidence that heart-healthy habits can be a powerful tool for reducing dementia risk.

The findings from this new study could be relevant for HD families, since we know that NfL levels rise as the disease progresses. When it comes to changes in NfL because of brain cell breakdown, many researchers think if we can hold NfL levels in check, that could suggest we’re stabilizing the progression of HD. Many groups are working toward a pharmaceutical approach to control NfL levels. This new research adds to that, suggesting that heart-healthy habits could help maintain general brain health.

While the relationship between heart and brain health is complex, this research supports a compelling idea: taking care of your heart could be one of the best ways to take care of your brain. So next time you hit the gym or choose a salad over fries, remember - your brain is probably benefiting too!

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