Tag: health

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Unlocking the code of longevity: How your diet might hold the key to a sharper mind

By Divya Vimal

We’ve all grown up hearing about the virtues of eating our greens and maintaining a healthy diet. But what if I told you that beyond just keeping your body in shape, a healthy diet could be your secret weapon against the ravages of aging and even dementia in later life? Yes, that’s right- those veggies might just be your ticket to a sharper mind and a healthier future! A groundbreaking study delved into this intriguing possibility, focusing on whether a healthy diet could slow down the biological clock and reduce the risk of dementia.

The researchers examined information from the Framingham Offspring Cohort, consisting of 1,644 participants aged 60 years and older, and has been under follow-up since 1971. They used algorithms also called epigenetic clocks to measure how quickly participants were aging biologically by assessing the methylation status of the DNA in white blood cells. One such epigenetic clock is DunedinPACE, which was utilized in this study as a predictor of health-span and lifespan. Meanwhile, they assessed diet quality using the Mediterranean Dash Intervention for Neurodegenerative Delay diet (MIND) diet score and tracked the occurrence of dementia and mortality. The MIND diet has been developed for prevention of dementia, combining key principles from two healthy diets (i.e. Mediterranean diet and Dietary Approaches to Stop Hypertension Diet). The MIND diet emphasizes high intake of neuroprotective foods such as fish, green leafy vegetables, berries, and nuts, while minimizing intake of red meat, butter, sweets. The MIND diet is a composite scoring system based on components of the MIND diet. Each component of the diet was scored from zero to one, reflecting the frequency of food consumption. Scores were assessed weekly, and the total MIND diet score, ranging from 0 to 15, was calculated as the sum of the 15 component scores. Higher scores indicated better adherence to the diet over the long term. 

Excitingly, the results revealed a compelling link between diet, aging, and dementia risk. Participants who adhered more closely to the MIND diet enjoyed a slower pace of biological aging (each 1-standard deviation (SD) increase in MIND diet score associated with a 0.20-SD slower DunedinPACE). For each improvement in the MIND diet score, there was a reduction of 34 fewer incident dementia cases per 10,000 people a year, suggesting that a healthier diet could lead to fewer cases of dementia over time- a striking finding! Digging deeper, about 27% of the diet’s impact on dementia risk was attributed to its effect on the aging pace. This suggests that a good diet might protect your mind by keeping your body younger at the cellular level.

Furthermore, a slower pace of biological aging was independently associated with lower risks of both dementia and mortality. This means that not only does a healthy diet potentially safeguard your mind, but it could also help you live longer.

Covariate analysis (statistical method) including factors like socio-economic status, genetics, lifestyle, and health conditions didn’t change the main results. Interestingly, there were no significant differences in how diet affected aging based on sex or APOE4 status (a genetic risk factor for Alzheimer’s). Furthermore, the study revealed that maintaining a healthy diet at different life stages, from mid-life to older age, was associated with slower biological aging, reduced risk of dementia, and lower mortality rates. Alternatively, similar analysis with the Mediterranean Diet Score and the Dietary Guideline Adherence Index mirrored the associations between different measures of diet quality and health outcomes underscoring the well-known health benefits of the Mediterranean diet. These findings collectively underscore the significant impact of diet on aging and health outcomes, emphasizing the importance of maintaining a healthy diet throughout life.

While the study had its limitations, such as a predominantly white cohort and participant recall bias, its implications are profound. It hints at the possibility that by monitoring our biological age, we might gain valuable insights into how to prevent dementia and age-related decline. Furthermore, the study couldn’t differentiate if a healthy diet directly affected organ health, leading to slower aging (egg before the chicken) versus its impact on cellular aging indirectly preserving organ health (chicken before the egg).

In essence, this study highlights the power of diet in preserving both body and mind. It paints a hopeful picture of a future where something as simple as dietary choices could be the key to a longer, healthier life with a more agile mind. 

Original paper

Reviewed by: Aline Thomas and Trang Nguyen

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How many candles on the cake this year?

Every year as we celebrate our birthdays, we mark the addition of a year to our lives. Our birthdays determine our chronological age measured in days, months and years since the day we were born. Biological aging on the other hand is another measure of aging that accounts for the gradual accumulation of cellular and tissue damage that occurs in the body as we grow older. Aging is a natural process and various factors contribute to biological aging, including our chronological age, genetics, lifestyle, nutrition, and physical activity. Research has shown poor nutrition and low physical activity can accelerate biological aging. Accelerated biological aging is marked by increased levels of certain hallmarks of cellular damage, leading to chronic diseases. Poor nutritional habits and sedentary lifestyles have been associated with increased risk of heart diseases, high blood pressure, cholesterol and type 2 diabetes. Additionally, over 60% of the aging population (>65 years) is expected to be affected by more than one chronic disease by 2030. Research has also shown that lifestyle interventions may reduce or delay the progress of biological aging. In this regard, Aline Thomas and colleagues obtained real life data from a large cohort of US adults to study the association between lifestyle behaviors and biological aging using mathematical models. They assessed signs of aging in individuals who engaged in some form of moderate to vigorous physical activity in their leisure time and followed a diet that resembled a mediterranean diet compared to individuals who followed a less-healthy lifestyle. A Mediterranean diet focuses on plant-based foods and healthy fats. It includes vegetables, fruits, whole grains, fish and extra virgin olive oil as a source of healthy fats. The researchers studied diet, exercise, and variations in healthy lifestyle behaviors across different age groups, genders, and body mass indices (BMI).

Dr. Thomas and colleagues combined data collected over a period of 20 years from 1999-2018 for their study. The study included 42,625 participants between the ages of 20-85 and assessed the adherence to the Mediterranean diet and an exercise regimen using a point based system. Inclusion of fruits and vegetables, legumes, cereals, fish and a ratio of mono-unsaturated to saturated fats were each awarded one point. A healthy Mediterranean diet also includes a mild-moderate amount of alcohol, which is 0-1 glass for women and 0-2 glasses for men. So, a point was given if a mild-moderate amount of alcohol was consumed. Dairy products and meat are not part of the Mediterranean diet. If participants had consumed these foods but had consumed it less than a specific amount, they were still awarded a point. The points were totaled and found to be between 0 and 9. Higher scores meant a higher adherence to the Mediterranean diet. Leisure time physical activity (LTPA) describes any physical activity performed during participants free disposable time. The researchers assessed LTPA based on the frequency, duration and intensity to calculate points / scores for each activity. They categorized the activity levels based on the scores per week into four groups ranging from – sedentary (0 points), low (<500 points), moderate (500-1000 points) and high (>1000 points). Biological age was calculated using an algorithm called PhenoAge. The algorithm calculates biological age based on chronological age and 8 biomarkers obtained from blood samples.

The study included individuals across different races, socio-economic backgrounds, marital statuses, income to poverty ratios, and with various lifestyle-related factors (e.g., smoking, BMI category, total energy intake), making it a representative population of US adults. The researchers found very interesting observations relating to diet and exercise. They discovered that adherence to a relatively healthy diet and engagement in  physical activity were independently associated with a lower biological age. Participants with a healthy diet and some level of activity were on average 1 biological year younger than the participants with the least healthy diet and sedentary lifestyle. Another very interesting finding was that individuals who had a less healthy diet but who were active even at a low level showed delayed biological aging. However, delayed biological aging was not found in participants with a healthy diet and a sedentary lifestyle, suggesting that moderate physical activity is a key component of healthy biological aging.

The findings of this study reiterates the need for better lifestyle choices across all strata of the population as the results were consistent regardless of age, sex and BMI category. A nutritious diet and moderately active lifestyle can have a positive impact on health, aging and quality of life. Getting older is inevitable, but you may be one year younger with a healthy diet and an exercise routine.

Reviewed by: Trang Nguyen, Giulia Mezzadri, Erin Cullen, Maaike Schilperoort 

 

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The Importance of Consistent Sleep for Memory Retrieval at the Neural Level

Sleep helps us remember the details of past events more clearly. When we sleep, neural mechanisms facilitate the consolidation of memories formed during the waking day. Specifically, memories are temporarily stored in a brain structure called the hippocampus. During the consolidation process, memories are replayed and integrated into long-term storage centers in the neocortex of the brain. Poor sleep impairs sleep-based memory consolidation and memory retrieval. In other words, when our sleep is fragmented, our memory is less clear. 

One way to assess the clarity of a memory is to measure neural similarity, or the overlap between patterns of neural activity.  My colleagues and I presented participants with a series of word pairs to remember while we recorded their neural activity using electroencephalography. We used this task to measure neural activity when participants studied (i.e., encoded) and were tested on (i.e., retrieved) the word pairs. The overlap between their neural patterns for a given word pair at study and test is an index of neural similarity.

Interestingly, we found that sleep quality was associated with neural activity for word pairs that were paired differently. When people had more consistent sleep quality from night-to-night (measured with wrist-worn monitors), they had greater neural similarity when they correctly rejected word pairs that were paired differently. For example, if they saw the pair “wing – clock” during the study period and correctly identified “fork – clock” as a different pairing at test, they demonstrated higher neural similarity. 

There were several strengths of the study. We used an objective measure of sleep quality — wrist-worn monitors. We also measured sleep quality for seven nights, which allows for assessing night-to-night sleep variations. Our participants were racially and ethnically diverse people across the adult lifespan. However, our study was limited by its small, convenience-based sample of participants (74 people) and cross-sectional design. We cannot determine if poorer sleep causes lower neural similarity with this data. 

Taken together, our study suggests that memory integrity, or the ability to clearly remember the details of past events, may be linked with consistent sleep patterns. Thus, in addition to sleeping for enough time, sleep consistency also contributes to better memory retrieval. 

Edited by: Trang Nguyen, Pei-Yin Shih

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