Which blood values should I have checked to age healthily?
Blood sugar, blood fats, and inflammation markers are best supported by the evidence if you want to age healthily. Alzheimer's blood tests are only meaningful when there are genuine memory or thinking problems, and always under the guidance of a specialist.
The studies behind 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. But take note: this is intended only for people who already have memory or thinking problems and are seen at a specialist memory clinic. A European expert group of 22 specialists recommends a step-by-step approach: first blood tests, then additional brain imaging or cerebrospinal fluid testing if needed. This is not a routine check for people without symptoms.
The quality of commercially available Alzheimer's blood tests varies widely. For early detection, a test must correctly identify at least 90% of people who are ill and avoid enough false alarms. If you want to use it to replace a brain scan or cerebrospinal fluid test, the requirements are even stricter. Many tests do not yet meet that bar, making an incorrect result a very real possibility. These tests should therefore only be carried out and interpreted by a specialist.
For cardiometabolic health, there is broader evidence. A study of 1,098 healthy participants showed that the composition of gut bacteria was linked to a wide range of blood values: fasting blood sugar and blood sugar after meals, cholesterol, triglycerides, and inflammation markers. A varied, plant-based diet was associated with both a more favourable gut bacterial profile and better outcomes. These are associations, not proof of cause and effect.
From a practical perspective, the studies support blood sugar, blood fats, and inflammation markers as worthwhile measurements for healthy ageing. Discuss with your GP which set of tests 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. The Alzheimer's claims come from guideline documents and expert consensus. The link between gut bacteria and blood values comes from one study of 1,098 participants in which people were observed over time. No studies combining many results or studies in which people were assigned to groups by chance are available to support a specific screening panel for healthy older adults.
How do you keep your brain healthy as you age?
Combining more physical activity 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, interesting developments to follow rather than actionable advice.
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 blood test for p-tau217 shows promising results as an early signal for Alzheimer's, but is not yet available as a routine test; discuss any concerns about memory or hereditary risk with your doctor.
What do immune cells in your brain do during ageing?
Microglia play an active role in brain ageing through fat build-up and energy shortage, but most of the evidence still comes from animal studies. There are no human treatments yet, so if you have concerns about memory problems, discuss them with your doctor.
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.