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Biological Age: A Predictor of Longevity and Healthspan

By Diana Licalzi, MS, RD, July 23, 2021

Rebecca Rusch on healthspan

Thanks to modern technological advancements, the average American lifespan has reached 79—41% higher than it was 100 years ago. But modern life has also resulted in an increase of chronic diseases, which now affect nearly half of all Americans. In other words, a long life doesn't always translate to a higher quality of life. [1-2] In fact, your chronological (AKA calendar) age might not accurately represent your body's internal or biological age at all. 

What is biological age? Biological age is your body’s internal age. It reveals the efficiency at which your body is working and how well it should be working given your chronological age. 

biological age healthspanAs lifespan continues to increase, our healthspan becomes increasingly important. Unlike lifespan, which is simply concerned with chronological age, healthspan encompasses biological, physical, and mental health throughout the aging process. Read about the factors that influence our biological age and the best ways to measure it. 


Chronological age vs. biological age

biological age healthspanYour chronological age measures your age in calendar years or the number of birthdays you've had. But chronological age isn't necessarily the best metric of aging, as our bodies age at different rates—an age of 70, for example, can look incredibly different from one person to the next. A combination of genetics and lifestyle factors, such as diet, exercise, stress, and sleep, all play a role in determining how fast or slow someone ages.

Biological age, on the other hand, can give a more complete understanding of a person's aging process. For example, some individuals may appear fit and independent in their 70s, while others may look frail and need assistance. Your biological age reveals how well your body is working and how well it should be working given your chronological age. 

 

Factors that influence biological age

Scientists continue to make headway in pinpointing the factors and biomarkers most closely linked to biological age and healthspan. Here's what we know so far.

Genetics 

Genetics influence our biological age and healthspan to a degree, but perhaps not as significantly as we've been led to believe. In fact, according to longevity scientist David Sinclar, Ph.D., genes only control approximately 20% of our healthspan, and the rest relies on the individual's lifestyle or environment. However, there are certain variations in genes that can influence age-related traits. And though we can't change our DNA, understanding these genetic predispositions can help influence how we choose to promote longevity in our own lives.

Diet

Leading longevity scientists agree that diet plays an integral role in the rate of aging—our diets can either promote inflammation or keep it at bay. And this is critical, as chronic inflammation is the core of the development of many age-related diseases, something scientists often refer to this as “inflammaging.” For example, the standard American is high in sugars, fats, and processed ingredients (pro-inflammatory) and low in fruits, vegetables, and fiber (anti-inflammatory). This imbalance leads to an accumulation of reactive oxygen species (ROS)—sometimes called "free radicals." A buildup of ROS can cause damage to cells, proteins, and DNA in the body. Over time, this can lead to accelerated aging and the development of many chronic illnesses.  

Furthermore, a plethora of research shows a strong relationship between the type of protein we consume and healthspan. One study examined the relationship between dietary protein, its sources (animal vs. plant-based), and the risk of mortality. After investigating the diets and death rates of over 2,000 participants, the researchers concluded that (1) a higher ratio of animal to plant protein and (2) an overall higher meat intake were both associated with an increased risk of mortality.

Another 2019 study analyzed mortality rates in Seventh-Day Adventists, a population that eats low to moderate amounts of meat. The results indicated that Adventists with the highest intakes of red and processed meat had a greater risk of all-cause mortality and cardiovascular disease (CVD) mortality compared to participants who ate no meat at all.[3] Reducing meat intake and replacing it with more plant-based proteins has been shown to reduce CVD risk (the number one cause of death in the U.S.) and many biomarkers related to it, including cholesterol, triglycerides, and glucose.[4-5] 

Exercise

Staying physically active also helps to maintain a robust immune system, a healthy body weight, and a lower risk of inflammation. Engaging in regular exercise can, therefore, significantly influence our biological age and increase our healthspan. This study showed that running four to five miles each week can lower the risk of death from a heart attack by 40% and all-cause mortality by 45%. 

Exercise also works to improve our biological age on a cellular level. A study published in the Journal of Preventive Medicine showed that individuals who exercise 150 minutes per week (the recommended guidelines in the U.S.) have aging markers nine years younger compared to those who led a sedentary lifestyle. Different forms of exercise can also activate longevity genes, thereby improving our healthspan. High-intensity interval training (HIIT) workouts have been shown to stimulate genes linked to longevity.[6] 

Biomarkers

Biomarkers can indicate the speed at which we age. Research shows that some biomarkers are more strongly correlated with healthspan than others. For example, blood glucose, or blood sugar, is the body's primary source of fuel, and maintaining optimal levels contributes to overall health and longevity. A wealth of peer-reviewed scientific literature suggests that longevity can be predicted by an individual's fasting glucose levels—in fact, one study of more than 5,000 people found that lower glucose levels were correlated with a longer lifespan. Furthermore, it’s well-established that lower cholesterol levels, particularly LDL (“bad”) cholesterol, can be predictive of healthy aging. Other markers such as vitamin D, cortisol, hsCRP (an inflammatory marker) all link to optimal healthspan as well. Blood biomarkers constantly shift in response to our nutrition, fitness, and lifestyle choices and can be improved over time by following personalized recommendations. 

Sleep

Sleep is extremely important for our overall health, and this includes our healthspan—consistent sleep deprivation may potentially increase the production of pro-inflammatory cytokines (markers of inflammation). What’s more, this systematic review found that sleeping for less than six hours a night is associated with a 12% increased risk of mortality.



Ways to measure biological age

There are several proposed ways of measuring biological age, three of which we will discuss here. Telomere length, epigenetic clocks, and biomarker predictors uniquely measure our internal age but are alike in their ability to be influenced by lifestyle factors. 

Telomeres and healthy aging

Telomere length

Research demonstrates a strong relationship between telomere length and aging. Telomeres, the structures at the end of chromosomes, tend to decrease with age—shorter telomeres are associated with lower survival and higher incidence of disease, and vice versa. However, dietary and lifestyle factors can impact their rate of attrition. Individuals with healthier diets and who exercise more tend to have longer telomeres compared to those with chronic diseases and who lead more sedentary lifestyles.[7-8]

There are several ways to measure telomere length (and, therefore, biological age) but all vary in their accuracy. The terminal restriction fragment (TRF) is the oldest approach to measure telomeres and remains the “gold standard” in research settings, but it is not commercially available. The “flow-FISH” (flow cytometry and fluorescence in situ hybridization) analysis has been used in clinical settings to measure telomere length but only in certain patients. Some companies now offer ways to measure telomeres through a method called quantitative polymerase chain reaction (qPCR), though variability in its accuracy and the lack of actionable information it provides has prompted some criticism.[9] 

Epigenetic clocks

The field of epigenetics examines the ways that our behaviors and environment impact how our genes work. One type of epigenetics called DNA methylation can cause genes to "turn off" by adding certain chemical groups to DNA, thereby blocking proteins responsible for reading a gene. Our environment, lifestyle, diet, and the general aging process can all impact DNA methylation, and epigenetic clocks are tools to measure this (thereby measuring biological age).[10] One of the most popular and more accurate clocks is based on the Horvath calculator—an algorithm developed by Dr. Steve Horvath that predicts biological age based on DNA methylation. Longevity focused companies have now started to commercialize the Horvath’s Clock to offer epigenetic age prediction tests to consumers.

Biomarker predictors 

InsideTracker’s InnerAge model relies on biomarkers and personalized data to estimate a biological age. InsideTracker’s team of data scientists identified biomarkers most strongly related to aging and combined these insights with machine learning to design a model that calculates InnerAge and the steps needed to lower it. The list of biomarkers ranges from those related to cardiovascular health like glucose and LDL (‘bad’) cholesterol to those focused on liver function like GGT. The list also includes biomarkers related to inflammation, immunity, blood oxygen saturation, and BMI, to name a few. 


InnerAge also guides you through an action plan to biohack your biological age and healthspan. This action plan combines peer-reviewed science with your blood data to deliver ultra-personalized nutrition and lifestyle recommendations. These recommendations target (1) general factors that significantly impact longevity, and (2) specific biomarkers (e.g., glucose, cholesterol) most strongly correlated with aging. To learn more about InnerAge, click here


A summary of biological age and healthspan

  • Healthspan focuses on the preservation of our biological, physical, and mental health as we age, and not just the length of time we are alive.
  • Your biological age reveals how well your body is working and how well it should be working given your chronological age. 
  • Several factors influence our biological age, including genetics, diet, exercise, biomarkers, and sleep.
  • There are several proposed ways of measuring biological aging, including telomere length, epigenetic clocks, and InnerAge. 
  • InsideTracker’s InnerAge model relies on biomarkers and personalized data to deliver a biological age.
  • InnerAge also provides an action plan to biohack your biological age and healthspan, combining peer-reviewed science with your blood data to deliver ultra-personalized nutrition and lifestyle recommendations.  



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Diana Licalzi, MS, RD 
  • Diana is a Content Strategist and Team Nutritionist at InsideTracker. As a Registered Dietitian and self-proclaimed "biohacker," Diana enjoys researching and testing the latest trends and technology in the field of nutrition and aging. You'll often find Diana , completing a 24-hour fast, conducting self experiments, or uncovering strategies to increase longevity. Follow her on Instagram at @dietitian.diana.

References

[1] https://www.cdc.gov/nchs/hus/contents2018.htm?search=Life_expectancy,

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5876976

[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6470727/

[4] https://pubmed.ncbi.nlm.nih.gov/26853923/

[5] https://pubmed.ncbi.nlm.nih.gov/29618018/

[6] https://www.cell.com/cell-metabolism/fulltext/S1550-4131(17)30099-2

[7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3370421/

[8] https://www.sciencedirect.com/science/article/abs/pii/S0091743517301470

[9] https://www.hopkinsmedicine.org/news/newsroom/news-releases/accurate-telomere-length-test-influences-treatment-decisions-for-certain-diseases

[10] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3752894/