Which blood values should I have checked to age healthily?
Blood sugar, blood lipids and inflammatory markers are the best-supported measurements if you want to age healthily. Alzheimer's blood tests are only meaningful in the presence of genuine memory or cognitive complaints, and always under the supervision of a specialist.
The studies underpinning this answer cover two things: blood tests for the early detection of Alzheimer's disease, and the relationship between gut bacteria and cardiometabolic blood values. They do not provide a complete screening package, but they do offer concrete starting points.
Blood tests that look for Alzheimer's proteins are promising as a first step. However, note that this is intended only for people who already have memory or cognitive complaints and are referred to a specialised memory clinic. A European expert group of 22 specialists recommends a stepwise pathway: first blood tests, then, if necessary, additional imaging or cerebrospinal fluid investigations. This is not a routine check for people without symptoms.
The quality of commercially available Alzheimer's blood tests varies considerably. For screening purposes, minimum standards of at least 90% sensitivity and 75% specificity apply. If you want to use them to replace a brain scan or cerebrospinal fluid test, you need at least 90% specificity. Many tests do not yet meet that threshold, which means false-positive or false-negative results are a real possibility. These tests should therefore only be carried out and interpreted by a specialist.
For cardiometabolic health there is broader evidence. A study in 1,098 healthy participants showed that the composition of gut bacteria was associated with a wide range of blood values: fasting and post-meal blood sugar, cholesterol, triglycerides and inflammatory markers1. A varied, plant-based dietary pattern was associated with both a more favourable gut microbiome and better outcomes. These are associations, not proof of cause and effect.
In practical terms, the studies support blood sugar, blood lipids and inflammatory markers as meaningful measurements for healthy ageing2,3,1. Discuss with your GP which package suits your situation. Alzheimer's blood tests belong with the specialist, not in a preventive check-up.
All claims are based on 4 controlled sources (PMID 40729527, 38365381, 33432175). The Alzheimer's claims come from guideline documents and expert consensus. The link between gut bacteria and blood values comes from one observational study in 1,098 participants. No randomised studies or multi-study summaries are available that support a specific screening panel for healthy older adults.
What can I do to keep my brain healthy as I age?
Combining more exercise with staying mentally active and eating a diet low in sugar and higher in omega-3 fatty acids currently gives you the best chance of a healthy brain. Spermidine and new insights into how the brain cleans itself are, for now, only interesting to follow.
What does high cholesterol do to your brain as you age?
High cholesterol in middle age likely increases the risk of dementia, but at older ages the relationship is less clear and cholesterol-lowering drugs have not been proven effective for the brain. Stable cholesterol appears wiser than strongly fluctuating values; discuss your risk profile with your doctor if you are concerned.
Why does your memory work less well as you get older?
Memory loss with ageing is a normal biological process with multiple clearly demonstrated causes, but you can slow it down: regular exercise and mental activity have the strongest evidence base.
Can I test my risk of Alzheimer's with a blood test (p-tau217)?
A p-tau217 blood test can help diagnose Alzheimer's with high accuracy within specialised memory care. Ask your doctor which specific test is being used and whether it meets the quality standards, because not every commercial version reaches the recommended threshold.
Do your brains really shrink as you get older?
Your brain does indeed shrink with age, particularly in areas involved in memory and planning. High blood pressure accelerates that process, while exercise and cognitive effort strengthen your brain's compensatory activity.
Can high blood pressure in your 40s cause dementia later in life?
High blood pressure in your forties demonstrably increases your risk of dementia later in life, and early treatment appears to reduce that risk. Get your blood pressure checked and discuss with your GP whether treatment is worthwhile.