【Coronavirus Update】Chlorine & Our Microbiome

by Denise Tam, Holistic Nutritionist

In light of the Coronavirus (COVID-19) and its continual spread throughout our city and the globe,  the Water Supplies Department had increased the amount of residual chlorine from 1 milligram per litre of drinking water to 1.2mg/l, to ensure hygiene and cleanliness in our drinking water [SCMP].

Secretary for Development Michale Wong said, “After increasing the amount of residual chlorine, it is still lower than the World Health Organisation’s suggestion of equal to or lower than 5mg/l [of drinking water] … it is suitable for safe drinking.”

Since the 20th century, chlorine has been used as a common drinking water disinfectant to ensure our tap water is safe for drinking. Chlorine is effective in eliminating harmful microbes and to prevent bacterial growth and the governing authorities have deemed them safe. However they are only looking at chlorine and not the by-products that come out of the reaction to water and other compounds.

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Chlorinated Water and Cancer

Chlorine on its own is already dangerous, but in water, it reacts to organic compounds that create chlorine byproducts (DPB’s) like trihalomethanes (THM) and haloacetic acids (HAA’s). These disinfectant by products (DPB’s) are more harmful than chlorine itself and more harmful than any of the other substances in the water like fluoride, antibiotics etc. THM’s enter in our bodies and turn into free radicals which can cause damage to our cells and DNA. In fact, researchers have linked chlorine in drinking water and the DBP’s to increased likelihood of developing cancers – especially bladder, colorectal, rectal and breast cancer. 

In fact Scientific American reported that  “A recent study conducted in Hartford, Connecticut found that women with breast cancer have 50-60 percent higher levels of organochlorines (chlorine by-products) in their breast tissue than cancer-free women.”

Chlorinated Water and Microbiome Change 

What’s further found while doing the study on colorectal cancer and chlorinated drinking water is that the beneficial bacteria that is correlated to colon cancer decreased with the presence of chlorinated tap water. The human microbiome houses 10 times the number of bacteria than our own cells. This means diversity in these healthy bacteria are crucial for our health and survival.

We know that around 70% of our immune cells live within our gut. So a healthy gut, means a strong immune system. The variety of probiotic strains is very important as demonstrated in the study with colon cancer, specific strains have specific purposes. Another popular study comparing the immune system of kids growing up in the city and kids growing up on the farm found that kids growing up on the farm had stronger immune systems because they were exposed to more types of bacteria, from the different animals, to the plants, to the dirt. We all need a little bacteria in our system, but we need the right bacteria and we need variety.  This is why I choose Udo’s Probiotics that uses probiotics that have been researched to survive stomach acid and uses human adapted strains that span across several variety of strains. 

How to Filter out Chlorine?

As always, we want to eliminate the source of the problem, in this case, chlorine in our tap waters. We need the chlorine to keep the unwanted bacteria and pathogens out, but we also don’t want to be drinking the chlorine. This is where I would recommend a very good water filter that can filter out chlorine and other substances found in our water. Boiling water can be an easy way to eliminate the chlorine though it will still leave you with other substances like heavy metals. 
Beyond drinking water, we can even breathe in THM and HAA’s when we take a shower, do the dishes or wash our vegetables. You can choose to get a filter for your showerhead and do wash your vegetables and do your dishes with only filtered water, but the practicality of all this is low.

In short, there’s no easy way to eliminate our contact with chlorinated tap water completely but we can do our best and also remember to do periodic detoxes and make sure our gut flora is well fed with probiotics. Particularly in this time of a potential pandemic with the Coronavirus (COVID-19), we need to be taking all precautions to keep our immune system healthy and strong. 



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