TEH tarik is practically a national treasure in Malaysia. Whether it's at the mamak for breakfast, during a mid-morning break or after dinner, that creamy, sweet cup of pulled tea is a comfort beverage for millions.
But you might have heard warnings from health-conscious friends or relatives that drinking too much tea can give you kidney stones because of the oxalate content.
With some Malaysians easily downing three to four cups a day, should teh tarik lovers be worried about their kidneys?
Verdict:
FALSE (with important context)
No, you're unlikely to get kidney stones from drinking teh tarik, even if you consume it regularly, according to multiple scientific studies. However, the relationship between tea and kidney stones is more nuanced than a simple yes or no answer.
Let's start with the concern: tea does contain oxalate, a compound that can contribute to calcium oxalate stones, which are the most common type of kidney stone.
Black tea contains approximately 86mg of oxalate per 1.5 litres, according to a study published in the journal Nutrients.
However, here's the surprising part: multiple peer-reviewed studies have found that tea consumption does not significantly increase kidney stone risk and may actually help prevent them.
A study published in PMC that examined 273 patients with calcium kidney stones found that daily green tea drinkers showed no difference in stone risk factors such as urine oxalate, calcium, urate, citrate and pH compared to non-drinkers. The study concluded that regular green tea intake is not a risk factor for oxalate-dependent stones.
Research on black tea yielded similar results. A study published in Nutrients involving 10 healthy men found that consuming 1.5 litres of black tea per day containing 86mg of oxalate did not significantly alter 24-hour urinary oxalate excretion. More importantly, urinary citrate, an important inhibitor of calcium stone formation, increased significantly.
Another study examining oxalate bioavailability from black tea found that tea-derived oxalate is of very low bioavailability, with only 2.4% of oxalate from tea being absorbed by the body. The researchers concluded that "at the present time, there is little overall support for the recommendation that kidney stone formers limit their intake of black tea".
A large analysis of over 194,000 participants found an inverse relationship between daily intake of tea and the risk of new kidney stone formation. The more cups of tea consumed per day and per week, the greater the protective benefit.
A case-control study involving Chinese adults published in Frontiers in Nutrition found that increased tea consumption was associated with a lower risk of kidney stones. Participants who drank seven or more cups of tea per day had a 27% lower risk compared to non-tea consumers.
So why doesn't the oxalate in tea cause kidney stones?
Several factors explain this. First, the oxalate in tea appears to be poorly absorbed by the body. Components in tea may actually inhibit oxalate absorption in the intestines.
Second, tea contains beneficial compounds, particularly catechins in green tea and polyphenols in black tea, that have been shown to inhibit the formation of calcium oxalate crystals. These antioxidant compounds may help prevent stones from forming.
Third, the fluid intake from drinking tea itself is protective. Staying hydrated is one of the most important factors in preventing kidney stones, and tea contributes to your daily fluid intake.
The US National Kidney Foundation (NKF) lists tea among protective factors for kidney stone prevention, alongside water, coffee, a DASH-style (Dietary Approaches to Stop Hypertension) diet and adequate calcium intake.
The NKF notes that while oxalate is naturally found in many foods including tea, a strict low-oxalate diet is not usually the best approach to prevent stones.
In fact, the foundation advises that people who eat more plant foods, including those containing oxalate, tend to have fewer kidney stones because these are packed with calcium oxalate stone inhibitors like potassium, magnesium, phytic acid and fibre.
However, there are important caveats to consider.
If you're someone who already has calcium oxalate stones and have been found through 24-hour urine testing to have high urinary oxalate levels despite adequate calcium intake, your doctor or dietitian may advise limiting very high oxalate foods.
In such cases, moderation with tea consumption might be recommended alongside other dietary changes.
Additionally, the type of tea matters. Instant teas, particularly those that are sweetened, may pose different risks. The NKF specifically mentions that sweetened iced tea should be avoided, likely due to the combination of added sugar and concentrated tea.
It's also worth noting that kidney stone prevention isn't just about oxalate. In fact, research shows that diet-related kidney stones are most commonly caused by too much salt, added sugar, meat and not enough water, calcium or fruits and vegetables, rather than from eating too many oxalate-containing plant foods.
For Malaysian teh tarik lovers specifically, the milk in the drink may actually provide additional protection.
The calcium in milk can bind to oxalate in the digestive tract before it reaches the kidneys, potentially reducing oxalate absorption.
So should you worry about your daily teh tarik habit? Probably not, unless you've been specifically advised by a doctor to limit oxalate due to confirmed high urinary oxalate levels and recurrent kidney stones.
The real kidney stone prevention strategies that matter most are staying hydrated, limiting salt and sugar intake, eating adequate calcium, avoiding excessive animal protein and maintaining a balanced diet rich in fruits and vegetables.
Your teh tarik isn't the enemy. In fact, it might even be helping.
References:
1. https://pmc.ncbi.nlm.nih.gov/
2. https://pmc.ncbi.nlm.nih.gov/
3. https://pubmed.ncbi.nlm.nih.
4. https://www.sciencedirect.com/
5. https://www.frontiersin.org/
6. https://www.kidney.org/kidney-
7. https://www.kidney.org/kidney-
8. https://www.kidney.org/kidney-
9. https://www.jrnjournal.org/
