If you want to take your healthspan strategy to the next level, you should arm yourself with the right data. We’re talking about more than the table-stakes data your general practitioner would track. This is about the next level of information on how your body may be aging in different dimensions. Since there are so many things you could potentially track, we set out to identify the 10 longevity biomarkers most frequently cited in lists.
Our search on longevity markers and blood tests turned up quite a few results. We filtered them down to the 15 most reputable sources we found from across the web (including this peer reviewed study: Biomarkers Related to Aging in Human Populations), and we compiled a list of the top 10 most cited longevity markers.
The list is not compiled in any particular order because what is most important to track will vary depending on what we are most interested in learning about.
ALT and AST
Alaninetransaminase (ALT) and aspartate aminotransferase (AST) are liver enzymes involved in amino acid metabolism. When it comes to blood work, these two enzymes serve as indicators of liver function and cell damage. When there is injury or disease in the liver, the body releases these two enzymes, both of which can be detected by a simple blood test. According to sources we found, normal ranges for these enzymes vary based on gender and the lab performing the analysis. Generally, ALT is considered normal if it is ≤45 IU/L in men, and ≤35 IU/L in women; normal AST is normal if it is 8–40 IU/L for men and 6–34 IU/L for women. Values outside of the normal ranges for both enzymes may indicate a problem with your liver. Because our livers are a crucial digestive organ, damage to the liver can affect the way we process nutrients and the way our bodies remove toxins. Additionally, some research suggests that elevated ALT levels are associated with increased risk for liver-related mortality and this study found that evaluated AST may reduce life expectancy by 10 years or more!
Currently, there are no guidelines on how frequently you should have liver functions tests, but if you are experiencing concerning symptoms, have never had a liver function test, or are taking potentially toxic supplements and/or medications, you should have your ALT and AST tested. To have these tests run, ask your doctor about running a liver panel or comprehensive metabolic panel the next time you have blood work done.
Testosterone or Estradiol
Testosterone and estradiol are the primary male and female sex hormones and are responsible for maintain normal function of body systems including the musculoskeletal, cardiovascular, and reproductive systems in men and women. Testosterone and estradiol can be monitored via a blood test. In men, testosterone level is considered normal if it is 300 to 1,000 ng/dL. Normal levels of estradiol in women vary depending on phase of menstruation and/or menopause; generally, levels are normal if they fall between 30-400 pg/mL in premenopausal womenand 0 to 30 pg/mL in postmenopausal women.
Age alters both male and female sex hormones, so it is normal to see your levels gradually decrease as you grow older. In men and women both, a reduction in sex hormones causes physical, physiologic, and emotional changes such as reduced bone and muscle mass and changes to the reproductive system. When levels of sex hormones fall too low, men and women are both at an increased risk for age-related chronic disease like heart disease as well as sarcopenia and osteomalacia/osteoporosis.
There are no guidelines on how frequently you should have your hormone levels tested, but it’s a good idea to test them at regular intervals if you are healthy (e.g., every 1-2 years) or have them tested regularly if you are taking hormone therapy or have a health condition which affects the endocrine system.
High Sensitivity CRP
C-reactive protein (CRP) is an acute-phase protein produced by the liver; its levels rise and fall in the presence of inflammation. CRP can be regularly tested as part of a routine blood test. In healthy adults CRP ranges should be <3 mg/L; elevated levels of CRP are an indicator of inflammation in the body.
Research suggests that CRP levels are an excellent predictor cardiovascular disease, cardiac events, mortality, and comorbidity in both men and women. The correlation of CRP with heart disease occurs along a continuum; this clinical update people with a CRP levels <1 mg/L are at the lowest risk for heart disease and that disease risk increases from there with individuals that have a CRP <3mg/L at the highest risk. Additionally, CRP is also associated with repeat cardiac events. This study showed that elevated CRP accurately predicts the likelihood of repeat cardiac events (e.g., heart attack, stroke) in individuals who already have heart disease.
Individuals who have heart disease should have their CRP monitored on a continuous basis (e.g., every 3-6 months). There are no guidelines in place for healthy individuals, but if you’d like to monitor your CRP level, ask your doctor about adding a CRP or hsCRP test to your next round of labs.
Albumin is a water-soluble protein commonly found in blood plasma. It acts as a transport molecule and helps to maintain oncotic pressure (a type of osmotic pressure) in the blood vessels. Albumin can serve as a marker of inflammation and is commonly included in routine blood tests. Normal levels of albumin fall between 3.5 to 5.5 g/dL and deviation on either side of the range can indicate possible health problems like dehydration, chronic diseases, or malnutrition. Research suggests that albumin is associated with heart disease, cognitive and functional decline, and mortality.
Individuals with type 1 or type 2 diabetes may be given routine microalbumin tests once a year by their doctor. If you have liver disease or other concerning symptoms like weight loss or swelling in the lower extremity, your doctor may also order an albumin test. For otherwise healthy individuals, you can ask for a CBC with differential to have the serum albumin test included the next time you have blood work done.
Vitamin D is a fat-soluble vitamin required for calcium absorption, as well as other body processes including those related to immune function, cell growth, neuromuscular function, and glucose metabolism. We obtain vitamin D either through our diet or by exposure to sunlight, although vitamin D deficiency is becoming more common among adults because we spend much more time indoors now than we did in the past. Normal levels of vitamin D range between 20-50 mg/mL. When levels fall below normal, you are at increased risk for health issues. For example, this meta-analysis found that low levels of vitamin D are associated with increased risk of CVD. Other studies have shown that vitamin D can prevent respiratory infections and lower the risk of cancer in children.
In healthy individuals, there are no guidelines for vitamin D testing. If you’d like a vitamin D test, ask your doctor to add it to your next round of blood work. If you’ve been diagnosed with a vitamin D deficiency, routine monitoring is required at least every 3 months to assess your progress and bring your levels back up to the normal range.
Glycated hemoglobin is a type of blood protein bound to a sugar molecule. As a lab test, HbA1C provides an estimate of your average blood sugar over the past 3 months; this can prove a useful tool in diagnosing and managing diabetes and most often used in that context. HbA1C is considered normal if it is between 4-5.6; a HbA1C of 184.108.40.206 is considered prediabetic, and a HbA1C <6.5 is considered diabetic.
A large proportion of research points to HbA1C as being linked with diabetes which is why it is used in diabetes care settings. However, HbA1C has also been associated with cognitive function; this study showed that A1C above 6.3 were associated with decreases in brain connectivity and cognitive function.
In healthy individuals, there are no guidelines for frequency of A1C testing, although HbA1C is a normal part of a metabolic blood panel and should be included in your next CBC with differential whether or not you have diabetes.
A lipid panel is the easiest way to garner information about your cholesterol levels and ratios. There is a long-established link between dietary fat intake, serum cholesterol and heart disease, so routine screening is necessary to prevent CVD and its comorbidities. Normal ranges for a lipid panel depend on what it is being measured and included. For reference, typical parameters and values found on your lipid panel includes:
- Total Cholesterol (TC) <200mg/dL
- Non-HDL <130mg/dL
- HDL men:>40mg/dL, women: >50mg/dL
- LDL <100mg/dL
- Triglycerides (TG) <150mg/dL
Additionally your lipid panel may contain information regarding:
- VLDL 2-30mg/dL
- TC: HDL <5.1
- TG: HDL <2
While cholesterol is necessary for synthesizing bile acids, making hormones, transporting lipid molecules in the blood, and energy, with the exception of HDL, an excess of blood lipids has continually been associated with heart disease and CVD mortality. For example, an elevated TG:HDL ratio (<2) is predictive of all-cause mortality, heart disease, and stroke. This study showed that the TG:HDL ratio is as good a predictor of heart disease and premature death as metabolic syndrome. Additionally, this study showed that high TC and LDL are associated with an increased risk for heart disease in older people.
Guidelines suggest lipid screening begin at age 20 and continue at least every 5 years. If you have a history of high cholesterol, heart disease, diabetes, or other chronic diseases, it is likely that your doctor will run a lipid panel more frequently.
CBC with Differential
A complete blood count (CBC) is a test that examines various types of blood cells and ratios and is generally regarded as a good test to generate a baseline for your overall health. CBC’s are not definitive but can be helpful in screening for and diagnosing conditions like anemia or for detecting the presence of infections. A typical CBC will include the following parameters and value ranges:
- Red blood cell count (RBC) men: 4.35-5.65 trillion cells/L, women:3.92-5.13 trillion cells/L
- Hemoglobin men: 13.2-16.6 grams/dL, women: 11.6-15 grams/dL
- Hematocrit men: 38.3-48.6%, women: 35.5-44.9%
- White blood cell count (WBC) 3.4-9.6 billion cells/L
- Platelet count men: 135-317 billion/L, women: 157-371 billion/L
Additionally, your CBC may contain information regarding:
- RBC indices (e.g., MCV, MCH, MCHC)
- RBC distribution width (RDW)
- WBC differential (counts of neutrophils, lymphocytes, monocytes, eosinophils, and basophils)
- Mean platelet volume (MPV)
- Platelet distribution width (PDW)
A CBC is a good test to pair with others get a more complete picture of your health, but some research has suggested that CBC parameters may be predictive on their own. For example, we found this study which showed that elevated WBCs are associated with diminished survival especially when it comes to CVD mortality.
CBCs are typically run at your doctor’s discretion and have no definitive guidelines for their frequency. We recommend having a CBC anytime you have unexplained symptoms or when you go for routine cholesterol checks.
Cortisol is a glucocorticoid—a steroid hormone primarily employed by the hypothalamic-pituitary-adrenal axis during the acute stress response. Because of this, cortisol is often referred to as the stress hormone. In healthy individuals, cortisol levels are diurnal and fluctuate throughout the day, usually peaking in the morning and waning as the day progresses. In addition to stress, cortisol plays a role in blood glucose control, nutrient metabolism, immunity, and skeletal development. Normal ranges for cortisol depend on the type of test that is run (i.e., blood, saliva, urine) and what time it was performed. Generally, serum cortisol is considered normal if it is 5-23 mcg/dL for a morning sample or 3-13mcg/dL for an afternoon sample.
As we age, changes in the composition of the adrenal glands (which produce cortisol) decreases production of hormones, although blood levels stay relatively stable. Research suggests that long-term exposure to cortisol can decrease immune function, reduce cognitive function and memory, alter metabolism, increase the risk of fractures, and set the stage for age-related disease.
Cortisol is not part of routine blood screenings in healthy individuals and thus has no frequency guidelines. To have a cortisol test, ask your doctor about adding it to your next round of blood work. You can also have cortisol tested individually with a saliva or urine test.
Insulin-like growth factor 1 (IGF-1) is a peptide hormone that plays a role in cell growth and metabolism, such as signaling to cells that the body has sufficient nutrients for proliferation and preventing apoptosis from occurring. Normal IGF-1 levels vary by age. Based on what we read, the minimal normal value for individuals age 21-30 is 85ng/mL, 60-70ng/mL for adults age 31-60, and 50-60ng/mL for adults 60+. For more specific ranges, check out this link.
As IGF-1 is related to cell growth, chronically high levels depending on the age group) have long been suspected as being detrimental to long-term survival. In animal models, lower levels of IGF-1 are associated with increased lifespan. In humans, higher than normal IGF-1 is associated with increased cancer risk and increased mortality.
There is no frequency of testing guidelines for IGF-1 and it is not routinely tested for by doctors. To check your levels, ask your doctor to add an IGF-1 test to your next blood draw.
In combing through the list we found, the above tests were the most frequently mentioned and you may find that some, most, or all of them help you gain a clearer picture of how well your longevity protocol is actually working. While most of the tests have no frequency of testing guidelines unless you have a chronic illness, you can address a specific concern by asking your doctor to order a single test, but to get the most out of your blood work, we recommend combining tests so that you get a complete picture.
Are you tracking any of these markers? Let us know about you experience: firstname.lastname@example.org
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