Kenya’s hot tea – a possible throat cancer risk, features in 2020 World Cancer Report

By Gatonye Gathura

The photo of a waiter pouring scalding hot tea for customers in Nyaru, a settlement in Elgeyo-Marakwet, Western Kenya is among the cover images on the 2020 Cancer Report launched on Tuesday.

A team of scientists at Tenwek Hospital in Bomet County has been investigating the high rates of food-pipe cancer in the region and suspect that consumption of hot tea is implicated.

The study was first reported in the Standard newspaper and later by KTN News eliciting strong debate in social media.

The paper published in June last year suggested that Kenyans drink the hottest tea ever recorded anywhere else risking possible development of esophageal cancer.

The research reported people in Western Kenya, a region with high rates of throat or food pipe cancer, prefer their tea at temperatures exceeding 72°C, the highest recorded so far.

Published in the Cancer Epidemiology Journal the work compared the temperatures at which Kenyans drink their tea and found it higher than in Tanzania, Brazil, China, Germany, US, Iran, and UK — areas of high throat cancers.

The study, also involving Brown University, US, National Cancer Institute, US, and The Mayo Clinic, US, found preferred temperatures for tea in Kenya was 1.5°C higher than any other studied population.

The researchers had involved 100 adult men and women accompanying patients at Tenwek Hospital.

First, the researchers had asked the study participants how they liked their tea, either “warm”, “hot”, or “very hot” with a majority, 64 percent, saying they like it hot.

Secondly, the temperature of the tea was measured using a digital thermometer, with most participants on average taking their tea at 72.1°C.

While the study reports no association between age and preferred temperature in tea, men were likely to consume hotter beverages than women by more than two degrees.

Low chemical levels

High beverage or food temperatures have been associated with a risk of throat cancer in several parts of the world.

The International Agency for Research on Cancer (IARC) has defined drinking temperatures above 65°C as “very hot” and considered this exposure as probably carcinogenic.

Previously, the hottest beverage temperature reported in any geographic location was from Tanzania, with a mean of 70.6°C.

But of note, the Kenyan study says 12 percent of participants, all men, had started drinking the tea immediately, at the poured temperature of 80°C.”

The good news is that Kenyan tea was found to contain low levels of the chemicals known as polycyclic aromatic hydrocarbons (PAHs) suspected to cause throat cancer.

The team had purchased 11 brands of commercial black Kenyan tea leaves and tested them for 27 PAHs.

All of the PAH levels, the study says, were found to be low in the samples, making it very unlikely that tea consumption is a significant source of PAH exposure in local populations.

Throat cancer is the sixth most common cause of cancer death worldwide with a high distribution in central Asia, Western Kenya and parts of South Africa.

Throat cancer is the most commonly diagnosed cancer at Tenwek Hospital, with over 400 cases diagnosed in 2016.

A striking characteristic of Bomet area, the study said, is the high proportion of cases diagnosed at a young age.

“This finding is particularly striking in the majority Kalenjin population, where nine percent of all cases are below 30 years old and 20 percent are under 40,” said the study.

In 2018, data from the World Health Organisation showed throat cancer to have killed 4,354 Kenyans, overtaking cervical, breast, stomach and prostate cancers.

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