Study: 3-4 cups of coffee a day slows ageing

Moderate daily coffee consumption - up to 3-4 cups a day - may be associated with slower "biological" ageing in people with severe mental illness. This is according to a study published in the journal BMJ Mental Health. In patients who drank this amount of coffee, telomeres (markers of cellular aging) were longer, which roughly corresponds to about "minus 5 years" of biological age compared to those who did not drink coffee.

However, no positive effect was observed when 5 or more cups were consumed - i.e. above the level that international regulators (including the NHS and the US FDA) consider a safe maximum (up to 400mg of caffeine per day).

What are telomeres and why it's important

Telomeres are sections of DNA at the ends of chromosomes that act as 'protective caps' (like the plastic tips on shoelaces). They naturally shorten with age, and this process is considered one of the indicators of cellular aging.

In people with severe mental disorders - psychosis, schizophrenia, bipolar disorder - telomeres, as previous work has shown, often shorten faster than the population average, indicating accelerated biological aging.

How the study was conducted

The study included 436 adult participants in the Norwegian TOP (Thematically Organised Psychosis) project:

• 259 people with schizophrenia;

• 177 people with affective disorders (bipolar disorder, severe depression with psychosis).

Participants were asked:

• how much coffee they usually drink per day;

• whether they smoke and for how long.

They were divided into 4 groups according to the amount of coffee:

1. 0 cups (44 people);

2. 1-2 cups;

3. 3-4 cups (110 people);

4. 5 or more cups per day.

Gender, age, ethnicity, diagnosis and medications taken were also taken into account.

Separately, it was noted that:

• people drinking 5+ cups were on average older;

• patients with schizophrenia generally drank more coffee than patients with affective disorders;

• about 77% of participants were smokers, and it was the 5+ cup group that had the longest smoking history.

What the telomere measurements showed

Telomere length was measured in white blood cells (white blood cells) from blood samples.

Result:

• the differences between groups in telomere length were J-shaped.

• Compared to those who drank no coffee at all, participants who consumed up to 3-4 cups a day had longer telomeres.

• Those who drank 5 or more cups no longer had this relationship.

After statistical adjustments (age, sex, ethnicity, smoking, diagnosis, treatment), it turned out that people who drank about 4 cups of coffee a day had telomere lengths that corresponded to biological age about 5 years younger than non-coffee drinkers.

Important caveats and possible explanations

This is an observational study, therefore:

• it cannot be claimed that coffee directly causes slower ageing;

• there may be other factors that were not taken into account.

The authors also note that they did not have data on:

• type of coffee (espresso, filter, instant, etc.),

• the time of consumption,

• exact levels of caffeine,

• other caffeinated beverages.

Nevertheless, there are plausible biological mechanisms:

• coffee contains antioxidants and anti-inflammatory compounds,

• telomeres are particularly sensitive to oxidative stress and inflammation,

• people with severe mental disorders already have factors that accelerate aging (stress, medications, lifestyle), so moderate coffee consumption could theoretically have a protective effect.

However, exceeding the recommended dose may have the opposite effect:
excessive amounts of caffeine can increase the production of reactive oxygen species and lead to cell damage and telomere shortening.

The authors remind:
international guidelines advise not to exceed 400 mg of caffeine per day, which roughly corresponds to four standard cups of coffee.

What this means in practice

• We are talking about people with severe mental disorders, not the general population.

• The study does not call for starting to drink coffee if there are medical contraindications (cardiovascular disease, sleep disorders, etc.).

• Rather, the data support the idea that moderate coffee consumption (up to 3-4 cups) may not only be safe, but potentially beneficial in terms of biological aging in this patient group.