I regularly drink tea (and the occasional espresso coffee) and sometimes feel cheated when so much research focuses on coffee. Now we have data from Great Britain showing that black tea is also associated with health benefits.
Here is a picture of my family and me having afternoon tea at the Ritz in London last month:
Today we look at a prospective study of nearly half a million participants in the UK Biobank cohort. Researchers published the study online in the Annals of Internal Medicine.
Tea, health, and longevity
Before we get into the recent tea study, let’s set some definitions. In a recent Medium piece, I talked about lifespan, health span, and longevity.
- Lifespan. The duration of an individual’s existence.
- Healthspan. Healthspan is the period of life spent in good health, free from the chronic diseases and disabilities of aging. Healthspan is a length of chronological time beginning at birth and ending when an individual is no longer in good health or is suffering from diseases or disabilities of aging.
- Longevity. Longevity is a balance of lifespan (living longer) and health span (living better).
British researchers examined nearly 500,000 adults with an average age of 57 years.
Approximately 85 percent of the subjects reported drinking tea, 90 percent reported consuming black tea, and most drank at least two cups daily; most drank two to three cups (29 percent), four to five cups (26 percent), or six to seven cups (12 percent) per day.
Let’s get to the results after a median follow-up of 11.2 years:
Those who drank at least two cups of tea daily had a lower all-cause mortality risk. Adding milk or sugar did not take away the benefit, and the tea’s temperature did not influence the results.
Compared to those with no tea intake, one cup per day tea drinkers had a five percent lower risk of death, a 12 to 13 percent lower risk for those drinking two or seven cups, and about a 10 percent lower risk for those drinking eight or more cups each day.
In addition to lower all-cause mortality risk, tea drinkers also had a lower risk of suffering cardiovascular death, ischemic heart disease, and stroke (compared with individuals who did not drink tea).
Why is tea associated with better health?
We do not know why people who drink tea may live longer. The large study I presented does not prove a causal relationship between tea drinking and better health.
With that important caveat in mind, study author Maki Inoue-Choi, an epidemiologist at the National Cancer Institute, offers that tea is “very rich in bioactive compounds” that reduce stress and inflammation, including polyphenols and flavonoids.
In support of these observations, a 2020 study using the UK Biobank database discovered an association between higher consumption of green and black tea and biomarkers related to cardiometabolic health, including lower cholesterol levels. Tea is also associated with very small decreases in blood pressure.
Should you double up on your tea habit? While the research findings are encouraging, the British study is observational — the evidence is not from an experiment, and the researchers infer results. Perhaps we tea drinkers do better because we put aside soft drinks. I would love to see a randomized trial comparing tea drinking versus no tea drinking.
In addition, the gains associated with tea consumption appear small in magnitude. I am reassured that my tea habit may have health upsides, even though the study offers nothing to make me drink more than I currently do.
Tea — Frequently asked questions (FAQs)
Let’s turn to some frequently asked questions about tea.
- Do all teas come from the same plant? Many define tea as the infusion of the plant camelia sinensis in water. So, in this sense, tea all comes from the same plant.
- How many tea types are there? There are six general groups of tea, including 1) Black tea (red tea in Chinese), a fully oxidized tea. 2) Green tea, a form that is barely oxidized. Green tea undergoes a process to remove excess water. 3) White tea is the least processed type; simply dry the leaves. 4) ) Oolong (blue) tea refers to partially oxidized teas. 5) Yellow tea; and 6) Dark (black in Chinese) tea, ones that are post-fermented (they have good mold growing on them).
年茶 三年药 七年宝 (one-year tea, three years medicine, seven years treasure). Thank you for joining me today. Do you drink tea?