A new study in BMJ Mental Health suggests that drinking 3–4 cups of coffee a day may help slow biological aging, at least in people with serious mental illness.

Participants who drank this amount had longer telomeres, the DNA “caps” that shorten with age. The difference was roughly equivalent to being five biological years younger than non-coffee drinkers.

Importantly, this benefit did not extend to those drinking 5+ cups, matching the upper limit recommended by the FDA and NHS.

Why Telomeres Matter

Telomeres protect chromosomes from damage, much like the tips on shoelaces.

They naturally shorten with age, but the process often accelerates in conditions like schizophrenia, bipolar disorder, and psychotic depression.

Because telomere length responds to lifestyle factors, researchers examined whether moderate coffee intake might offer some protection.

In this study, researchers analyzed 436 adults from the Norwegian TOP Study:

• 259 with schizophrenia
• 177 with affective disorders

Participants were grouped by coffee intake (none, 1–2 cups, 3–4 cups, or 5+ cups). Smoking, common in this population, was also considered, since it affects caffeine metabolism.

What the Study Found

Researchers measured telomere length from blood samples and found a J-shaped pattern:

• 3–4 cups/day → longest telomeres
• None → shorter telomeres
• 5+ cups/day → no benefit

After adjusting for key factors, moderate drinkers’ telomere lengths resembled those of people five years younger.

Possible Biological Reasons

While observational, the study points to likely mechanisms. Coffee contains antioxidants and anti-inflammatory compounds that may help reduce oxidative stress,  a major driver of telomere shortening. The authors note that telomeres are especially sensitive to these stressors, which may explain the association.

Coffee Is Popular, But More Isn’t Better

Coffee is widely consumed (over 10 billion kilos globally per year), but exceeding 400 mg of caffeine/day may actually increase oxidative stress and contribute to telomere shortening. Moderation appears key.

Although the study focused on individuals with psychiatric conditions, the findings align with broader research suggesting that moderate coffee intake can support aspects of long-term health.

As always, factors like caffeine sensitivity, sleep quality, medications, and adrenal health matter. If you’re wondering what level of coffee intake is healthiest for you, Dr. Wiggy and our team can help guide you.