Blood biomarkers to track longevity

Blood biomarkers to track longevity

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Until recently, blood tests have mainly been used to assess whether anything is seriously wrong with your health.

Now however, private at-home blood testing is widely available in most countries, with the aim of prevention, progress tracking, and health optimization, rather than simply diagnosing illness.

In this article, we'll examine which specific blood biomarkers are most closely linked to age-related decline and how you can track your progress as you implement new lifestyle changes or supplement regimes. We’ll also look at the healthy ranges for each biomarker, along with the optimal ranges you should be aiming for if you’re looking to maximise your health and longevity.

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Biomarkers for assessing metabolism

Glucose is very tightly regulated within the body and is a good indicator of metabolic function. The amount of glucose in the bloodstream is controlled through the release of the hormone insulin, but this delicately balanced mechanism can become disrupted as we age.

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Diabetes develops when your body becomes desensitised to insulin, meaning that when it is released, it no longer has the effect of bringing down glucose levels. Even slightly elevated glucose levels put you at a much higher risk of cardiovascular disease, cognitive decline, and other age-related diseases, so it’s important to not just prevent diabetes but avoid prediabetes and detect changes early ^{[1, 2]}. It is also no coincidence that many medications and interventions linked to lifespan extension, including metformin, insulin, and intermittent fasting, primarily affect glucose control ^{[3, 4]}.

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Fasting blood glucose

Measuring your fasting blood glucose levels is a simple and effective way to assess glucose metabolism. The range of fasting blood glucose levels for a non-diabetic are shown below.

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• >125 mg/dL (>7 mmol/L) = High
• 100–125 mg/dL (5.6–7.0 mmol/L) = Borderline high
• 65–99 mg/dL (3.6–5.5 mmol/L) = Healthy 
• 65–80 mg/dL (3.6–4.4 mmol/L) = Optimal
• 50–64 mg/dL (2.8–3.6 mmol/L) = Borderline low
• <50 mg/dL (<2.8 mmol/L) = Low

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HbA1c

HbA1c levels allow you to judge how well your glucose levels have been controlled over the past 2-3 months. It is a measure of what percentage of the haemoglobin in your red blood cells are bound to glucose molecules. Because the average lifespan of a red blood cell is 3 months, measuring HbA1c gives historical insight and is often seen as a superior method for assessing glucose metabolism than fasting glucose level ^[5]. Reference values for HbA1c are shown below.

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• >6.5% = High
• 5.7–6.5% = Borderline high
• 3.0–5.7% = Healthy
• 5.0–5.5% = Optimal
• <3% = Low

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Albumin

Albumin is the most abundant protein found in our blood and plays a crucial role transporting compounds around our body, as well as helping to control blood pressure and pH. Albumin levels decrease with age and low concentrations are associated with reduced muscle mass death in older adults ^[6]. Even small decreases or increases within the healthy range indicate a greatly increased risk of cardiovascular disease, as shown by the graph below ^[7].

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Ensuring that your albumin levels are within the optimal range and remaining relatively stable is therefore a great way to judge your longevity. Healthy and optimal levels of serum albumin are shown below ^[8].

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• 34–54 g/L = Healthy
• 45–50 g/L = Optimal

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Cholesterol and triglycerides

Cholesterol is a type of lipid (or fat) that is produced by every cell in our body and is crucial for energy production and transport. There are two main types: LDL-C and HDL-C (low- and high-density lipoprotein cholesterol). Broadly speaking, high levels of LDL are unhealthy, whereas high amounts of HDL are necessary for good health. As with glucose, our body’s ability to maintain healthy amounts of cholesterol declines with age, so keeping track of the levels in your blood provides a valuable insight into how you are aging.

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LDL-C

Levels of LDL-C naturally increase with age and high concentrations are associated with increased risk of cardiovascular disease, dementia, and death ^{[9, 10]}. It’s therefore crucial that you maintain low levels if you’re looking to extend your healthy lifespan. Reference values for LDL blood concentrations are as follows ^[11]:

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• >160 mg/dL (>8.9 mmol/L) = High
• 130–159 mg/dL (7.2–8.8 mmol/L) = Borderline high
• 100–129 mg/dL (5.6–7.2 mmol/L) = Healthy
• <100 mg/dL (<5.6 mmol/L) = Optimal

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Triglyceride:HDL-C ratio

HDL-C levels on their own can be useful, but they are more informative if they’re compared to the amount of triglycerides (another type of blood fat) present in your bloodstream. An elevated triglyceride:HDL-C ratio is one of the most reliable indicators of future cardiovascular disease ^[12], so it’s worthwhile keeping it low! Reference ratios are shown below.

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• >6 = High
• <4 = Healthy
• <1 = Optimal

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Triglycerides

Looking just at triglycerides is also useful for judging your health and longevity, as low levels have been shown to greatly reduce the risk of heart disease, cardiovascular disease, diabetes, and death ^[13-16]. You can see what values to aim for below ^[11].

• >200 mg/dL (>11.1 mmol/L) = High
• 150–199 mg/dL (8.3–11.1 mmol/L) = Borderline high
• <150 mg/dL (<8.3 mmol/L) = Healthy
• <90 mg/dL (<5.0 mmol/L) = Optimal

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C-reactive protein

Chronic inflammation is recognised as one of the major causes of age-related decline and disease. The concentration of circulating C-reactive protein (CRP) is directly correlated with inflammation levels, making it a great marker for assessing overall inflammation and, by extension, determining how well placed for a long and healthy life you are. Low CRP is associated with better physical and cognitive function and healthier aging overall ^[17]. High levels are linked to a greatly increased risk of cardiovascular disease, as well as diabetes, kidney disease, Alzheimer’s, Parkinson’s disease, and mortality (as shown in the graphs below ^[18]).

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A standard CRP test is only sensitive enough to detect whether there are dangerously high amounts of CRP present (>10 mg/L). To benchmark and track your longevity, it is valuable to use a high-sensitivity CRP (hsCRP) test which provides far greater accuracy at lower levels (0.5–10 mg/L) and so allows you to detect low-level inflammation that may hint at problems to come in the future.

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For a standard CRP test: <10 mg/L = Healthy

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For hsCRP:

• <3 mg/L = Healthy‍
• <1 mg/L = Optimal ^[19]

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Conclusion

If you are taking steps towards extending your healthy lifespan through diet, lifestyle changes, or supplements, tracking your progress is incredibly important. It helps with motivation, and allows you to develop personalized routines linked to tangible benefits. Without tests to benchmark your progress, it’s hard to know which aspects of your routine are working for you and which are a waste of time or money, and that’s where blood biomarker testing can help. 

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Gone are the days where blood tests were only ordered by a doctor in response to a problem. Modern medicine is all about prevention, which means maintaining optimal levels rather than just acceptable ones. 

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References

1. Diabetes and Altered Glucose Metabolism with Aging - PMC 
2. Age-related Changes in Glucose Metabolism, Hyperglycemia, and Cardiovascular Risk - PMC
3. Berberine, a Herbal Metabolite in the Metabolic Syndrome: The Risk Factors, Course, and Consequences of the Disease - PMC 
4. Intermittent Fasting and Metabolic Health - PMC 
5. Aging is associated with increased HbA1c levels, independently of glucose levels and insulin resistance, and also with decreased HbA1c diagnostic specificity
6. Lower serum albumin concentration and change in muscle mass: the Health, Aging and Body Composition Study
7. Change of Serum Albumin and Risk of Cardiovascular Disease and All-Cause Mortality: Longitudinal Aging Study Amsterdam 
8. Commonly used clinical chemistry tests as mortality predictors: Results from two large cohort studies
9. ​​Low‐density lipoprotein cholesterol and lifespan: A Mendelian randomization study - Daghlas - 2021 - British Journal of Clinical Pharmacology - Wiley Online Library
10. Blood cholesterol and risk of dementia in more than 1·8 million people over two decades: a retrospective cohort study - The Lancet Healthy Longevity
11. 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol
12. Identifying cardiovascular disease risk and outcome: use of the plasma triglyceride/high-density lipoprotein cholesterol concentration ratio versus metabolic syndrome criteria
13. Influence of serum triglyceride levels on the risk for myocardial infarction in 12,510 middle aged males: interaction with serum cholesterol
14. Effects of blood triglycerides on cardiovascular and all-cause mortality: a systematic review and meta-analysis of 61 prospective studies
15.  Changes in Triglyceride Levels Over Time and Risk of Type 2 Diabetes in Young Men - PMC
16. Low nonfasting triglycerides and reduced all-cause mortality: a mendelian randomization study
17. C‐reactive protein and ageing - Tang - 2017 - Clinical and Experimental Pharmacology and Physiology 
18. Interleukin-6 and C-reactive protein, successful aging, and mortality: the PolSenior study 
19. Optimizing Biological Age: C-Reactive Protein (hs-CRP) | Michael Lustgarten

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