Cancer
April 01, 2019
Figure 1: Preferred Tea Temperature & Esophageal Cancer Risk. Individuals who preferred their tea piping hot had a significantly higher risk of developing esophageal cancer over 10 years.
Tea is a fantastic drink. Unlike soda or juice, tea has no calories, it boosts your metabolism, and may offer other benefits that we're still discovering.
Tea (plain, and multiple varietals) consumption appears to be safe and may be associated with improved CVD health and blood lipids based on large observational studies and meta-analyses. Of note, the evidence is based on tea consumption (sometimes >5 cups/day) without added sugars, sweeteners, or milks and creams (both animal- and plant-based).
However, a new study shows that certain tea preparation techniques and preferences may increase your risk of esophageal cancer.
Researchers followed 50,045 individuals in Iran, a country where people love drinking tea, to see whether tea temperature correlates with esophageal cancer risk.
They found that volunteers who preferred drinking their tea while it was very hot (>140 degrees F) had a significant increase in their risk of developing esophageal cancer over 10 years.
Figure 2: Tea Brewing Time and Esophageal Cancer Risk. Individuals who allowed their tea to brew for longer before drinking it had a significantly lower risk of esophageal cancer. Allowing tea to cool for 5 minutes is best.
A similar relationship was seen for tea brewing time. Volunteers who let their tea sit for longer had a lower risk of esophageal cancer. People who preferred to drink their tea immediately after it's poured had an approximately 50% higher risk of developing esophageal cancer, even after adjusting for age, smoking, diet, alcohol consumption, and education.
Letting tea cool for 5 minutes or more correlated with a near normal, if not lower, risk of esophageal cancer.
Figure 3: Basic Statistics on Esophageal Cancer in the United States. Esophageal Cancers are only 1% of all cancer diagnoses in the United States, according to the SEER database from the National Cancer Institute. However, it tends to be deadlier than other cancers and thus it makes up 2.6% of all cancer deaths.
Of course, this all needs to be put in perspective. Esophageal cancer is one of the rarer cancers in the United States. It only makes up 1% of all cancer in the United States.
However, it tends to be deadlier than other cancers. It has a 5 year survival rate of 19.2% overall, according to the National Cancer Institute. Therefore, it makes up 2.6% of all cancer deaths which is disproportionately higher than its prevalence.
Source: Cancer Stat Facts: Esophageal Cancer
Figure 4: Esophageal Cancer Survival Statistics. Esophageal cancer has a low 5 year survival rate. However, this is highly dependent on when it's diagnosed. Esophageal cancer cases that are diagnosed after it has metastasized and spread to distant organs have a dismally low 5% 5 year survival rate. Meanwhile, diagnosing tumors before they have spread to lymph nodes have a 45% 5 year survival rate.
The overall 5 year survival rate for esophageal cancer has been estimated at 19.2% by the SEER cancer database.
Source: Cancer Stat Facts: Esophageal Cancer
However, this rate depends greatly on when the cancer is diagnosed. If the cancer has metastasized to distant organs and has spread around your body, the prognosis dim. The American Cancer Society estimates a 5% 5 year survival rate.
However, if the cancer is diagnosed before it has spread to the lymph nodes and local tissue, it has a 45% survival rate.
Source: Survival Rates for Esophageal Cancer
This study shows that a very simple tweak in how you prepare your tea can make it even healthier. Just letting it sit for a few more minutes can dramatically reduce your risk of getting a very deadly form of cancer.
Given that the primary variable studied was beverage temperature, this data suggests that individuals who drink very hot coffee may be at a similar risk.
The Working Group found no conclusive evidence for a carcinogenic effect of drinking coffee. However, the experts did find that drinking very hot beverages probably causes cancer of the oesophagus in humans.
Even with this data, we want to note that tea is generally very good for you. In several studies, researchers have found that tea may reduce your odds of diabetes, alongside a weight loss regimen, and can increase calorie burn.
Soda and sugary soft drinks are likely more dangerous than tea overall, even if you prefer your tea steaming hot. A recent study out of Harvard has linked sugary drinks to a significantly higher risk of heart disease and overall mortality. Given that the link between tea and cancer was only found in a relatively rare form of cancer, replacing soda with tea is probably still a good idea.