Whole-Blood NAD Tied to Heart Disease, Not Age, in 1,068 Adults

NAD sits at the center of cellular energy handling and metabolism. Animal work found age-related declines in muscle, brain and skin tissue. That work helped fuel interest in boosters such as nicotinamide mononucleotide and nicotinamide riboside, sold with healthy-aging claims. Human blood evidence had been mixed. The Vilnius team tested a broad claim in a big sample. Its result is narrower than a claim that NAD never falls: it says whole-blood NAD did not fall with age in healthy adults. The authors note the result challenges the prevailing narrative that NAD declines with age and needs restoration. But they do not measure supplements. The paper also does not replace animal tissue findings; it adds human blood data. The gap between blood and tissue remains central. [1]

The authors explicitly state that causality was not established. It remains unclear whether lower NAD contributes to cardiovascular disease, results from the disease itself or reflects other underlying factors. Those three possibilities are different, and the data cannot choose among them. The study also does not show that raising NAD through supplements can prevent or treat cardiovascular disease or hypertension. A lower level in people with disease is not proof that restoring the level helps. The paper presents the heart link as a question for further work, not as a treatment pathway. It reports no intervention and no trial of NAD boosters. That limit applies even to the clearest hypertension finding. Without temporal or experimental evidence, direction and mechanism stay open. The reported data cannot say which came first. [1]

A commentary alongside the paper, by Stephen Gardell and Joseph Baur, flags the limits of treating blood NAD as a proxy for NAD in muscle or brain. Red blood cells carry most of the NAD measured in whole blood, and their metabolism differs from other cell types. Because red blood cells supply most of the signal, a whole-blood figure cannot be read directly as an organ-level measurement. The Vilnius authors acknowledge that whole-blood readings do not necessarily mirror concentrations in individual tissues. That caveat matters because much of the longevity case rests on tissue studies, including animal findings in skeletal muscle, brain and skin. A blood result cannot simply be projected onto organs. Still, the authors argue that a blood marker need not reproduce tissue measurements to be useful. Many clinical markers work through accessible blood samples rather than biopsies or specialized imaging. The debate is about what whole-blood NAD represents, not whether the molecule matters. [1]

The authors' defense of blood testing is practical. Direct tissue measurement can require invasive biopsies or specialized imaging; blood draws are easier to scale. That makes large monitoring studies possible. But accessibility is not validation. The paper does not show that whole-blood NAD is an established clinical test. It shows a statistical association in one large sample. The commentary and the authors' response leave a gap between a promising marker and a usable one. A useful test would need to predict something meaningful, be interpretable across people and hold up in further studies. The current paper lays groundwork for those questions. It does not answer them. The result is best read as a signal for research, not a label for patients. That distinction should guide coverage and marketing alike. [1]

NAD boosters are promoted as a way to counter age-related NAD loss and support healthy aging. The study found no evidence of a blanket whole-blood NAD decline among healthy adults. That weakens a simple marketing rationale based on universal depletion. It does not establish that supplements have clinical benefits. The paper reports no trial of NAD-boosting supplements and no outcome data on prevention or treatment. The authors also state that the study does not demonstrate that increasing NAD can prevent or treat cardiovascular disease or hypertension. Two questions should be kept separate: whether healthy adults have a general blood deficit, and whether raising NAD changes disease outcomes. The paper addresses the first more directly than the second. It complicates the story without supplying a replacement treatment claim. Anyone reading supplement claims should note that the study reports associations, not outcomes from supplementation. [1]

The team names two follow-up tasks: determine whether whole-blood NAD measurements can help predict cardiovascular risk, and investigate the biological mechanisms behind the NAD-cardiovascular association. Those are future questions, not findings. The authors frame prediction and mechanism as next steps; the source does not report that either has been achieved. Whether prediction will hold is open. Whether mechanisms will explain the link is open. Follow-up work would also need to clarify how blood NAD relates to tissue NAD. Other questions include whether the pattern holds in different samples and in designs that track people over time. The source report does not describe an intervention trial. It cannot show what happens when NAD is changed. A scenario worth watching is a longitudinal study that measures NAD before and after cardiovascular events. Another is mechanistic work on hypertension. Neither is established here, and neither should be reported as a likely outcome. [1]

The study's main contribution is to move cardiovascular health into the frame when whole-blood NAD is interpreted. Its main caution is equally important: a blood association is not a treatment, and a group pattern is not a diagnosis. The authors present the heart link as a potentially important question, not a settled clinical finding. Whether whole-blood NAD becomes more than a research signal depends on prediction studies, mechanism work and clearer tissue comparisons. For now, the evidence supports a narrower statement: in this sample, whole-blood NAD did not fall with age in healthy adults, and lower levels were tied to cardiovascular disease, especially hypertension. Cause, clinical use and supplement benefit remain unresolved. Those limits should travel with every headline. [1]

Sources

Medical Xpress

Prepared with AI assistance from the cited sources.