Decaffeinated tea and coffee: unravelling the truth from the myths

It’s standard advice to drink less caffeine during pregnancy, and as part of my process of switching to a pregnancy diet while trying for a baby, I’ve replaced a lot of the caffeinated tea I drink with decaf. I don’t like coffee but I drink a massive quantity of tea – usually four or five huge mugs a day at work, and another at home in the evening. In normal mug terms, that’s probably getting on for seven or eight cups.

Both BBC Health and NHS Choices recommend that pregnant women drink no more than 200mg of caffeine per day. To put this in context, you can drink the following approximate amounts of tea and coffee:

  • 1.5 mugs of filter coffee
  • 2 mugs of instant coffee
  • 2.5 mugs of tea

There are also small amounts of caffeine in chocolate, and if you drink coke or other energy drinks then you need to factor this in too (the websites listed above contain breakdowns of the amount of caffeine in various different drinks).

So clearly my eight mugs of tea per day is way too much.

The answer to this seems really easy – I’ve started drinking a ‘real’ caffeinated tea first thing in the morning, and then switching to decaf for the rest of the day. Decaf tea still contains a little caffeine, but even with my high consumption I’d be well below the recommended 200mg per day (if you drink a lot of coffee you might still need to cut down, even on decaf). I tried a few different decaf teas, and my favourite by a mile was PG Tips – it’s my favourite for caffeinated tea too, and I could hardly tell the difference. I like herbal tea and I’m trying to replace some of my usual tea intake with that – luckily I hate green tea, which contains caffeine, although not so luckily I also don’t like the taste of rooibos, another naturally caffeine free option.

I thought it was all going swimmingly. Then, in my usual panic-stricken way, I started reading round to check that drinking too much decaf tea isn’t a problem in itself. And – oh no – I started finding articles like these:

It turns out there are three main ways of decaffeinating tea – using water, CO2 or this nasty-sounding dichloromethane system. The latter is the cheapest and easiest method and all the major tea manufacturers in the UK use it (according to the Twinings website), although in America it’s used less nowadays. I didn’t really want to spend a fortune sending off for expensive teas from abroad that use one of the other two techniques, so I looked into it further to find out how bad the chemical process really is.

I found a pretty well-balanced article in yes dichloromethane is bad, but the amounts left in tea at the end of the decaffeination process are absolutely miniscule. Lab tests on rats (I’m not generally a fan of animal testing but that’s a story for another time) haven’t shown any negative results even at the rate of 70-80 cups of tea or coffee per day. Most sensible websites seem to back this up, like which says that modern decaffeination using this method leaves traces of the chemical well within safe limits. Unfortunately it’s pretty hard to find any really useful science on this topic as most refers to inhalation of dichloromethane in things like solvents and paint strippers – in which circumstance it’s definitely a bad thing.

I usually find that once I’ve done some research on this kind of topic, I’m confident making a decision one way or another. This one I’m finding a lot harder, because much of the information on the web is very emotively written – the decaffeination process seems to be a topic which evokes a lot of panic and bad science. It’s so hard to get hold of tea made with other methods, but once I’ve finished my current supply of PG decaf I might try to find some that’s not going to bankrupt me – and in the mean time I’ll carry on as I am.

In the long run I’m benefitting my baby-to-be by not drinking caffeine, and I don’t want to give up tea entirely because it’s one of my biggest pleasures! Stopping drinking alcohol, cutting down on oily fish and reducing my caffeine intake were easy decisions because all the science and health advice is in agreement. When it comes to stopping drinking decaf tea, I feel like this is an area in which self-sacrifice for the sake of making my body the healthiest possible place to grow a baby might be misplaced. For now, I’m going to trust that the scientists and manufacturers have got things right and that the limits they’ve imposed for safe consumption really are safe.


How much fish should I eat during pregnancy and conception?

I’m a pescatarian, which means I eat fish but no other kinds of meat, and I would hate to give up eating it. For a start, it’s delicious! But more importantly, it’s really, really good for me, especially as I don’t get protein from other kinds of meat.

Eating more fish is one of the NHS website’s top eight tips on on eating healthily – as well as lean protein, fish contains lots of vitamins and minerals, omega-3 fatty acids and fish oils which help brain and eye development, reduce inflammation and help prevent cardiovascular disease. It’s just a great source of so much good nutrition.

As is so often the case, however, we humans have managed to mess things up by polluting the world around us – in this case we’ve polluted the seas with mercury and other heavy metals, mainly (according to Wikipedia) from coal power stations and chlorine production plants. The Wikipedia page on Mercury in Fish has a comprehensive table on which fish absorb the most mercury – tilefish, swordfish and shark are the worst and luckily they’re not commonly eaten in England. In general oily fish are higher up the table, and white fish are lower (but that’s only a rough guide).

The human body is usually able to eliminate this mercury, but it can be toxic to foetuses, damaging their nervous systems. This is a deeply horrible thought, and when you consider that raw fish such as shellfish are also not recommended as they can cause food poisoning, I imagine most people’s first reaction (and mine too) is to steer miles clear of anything that’s been anywhere near the sea.

We need to be really careful about having that reaction, though, because when I read more about it, omega-3 is really important for a developing baby – according to a 2007 study (summarised in lots of news articles at the time including on the BBC and Guardian websites) it boosts intellect, improves social skills and even benefits eyesight, among lots of other things. Plus, there are all the vitamins, minerals and proteins to consider – all of these are good for nourishing a baby, and we all know that it’s much more effective to get them through diet rather than supplements.

All this conflicting information might seem very confusing, but actually it’s in line with what the usual sources of information on diet during pregnancy recommend – you should carry on eating fish, but in moderation. The brilliantly thorough NHS webpage on fish and shellfish sums this up, and I’m going to paste a big chunk of it here so you have it to hand:

“Eating fish is good for your health and the development of your baby. But pregnant women should avoid some types of fish and limit the amount they eat of some others.

When pregnant, you can reduce your risk of food poisoning by avoiding raw shellfish. Below is advice from the Scientific Advisory Committee on Nutrition and the Committee on Toxicity about eating fish when trying to get pregnant, or when pregnant or breastfeeding:

  • Shark, swordfish and marlin: do not eat these if you are pregnant or trying to get pregnant. All other adults, including breastfeeding women, should eat no more than one portion per week. This is because these fish can contain more mercury than other types of fish, and this can damage a developing baby’s nervous system.
  • Oily fish: if you are trying for a baby, pregnant or breastfeeding, you should have no more than two portions of oily fish a week. A portion is around 140 grams.
  • Canned tuna: if you are trying for a baby or are pregnant, you should have no more than four cans of tuna a week. This is because tuna contains higher levels of mercury than other fish. If you are breastfeeding, there is no limit on how much canned tuna you can eat.

Even though I’m still not pregnant yet (*sob*) I’m trying to get into these good habits now so I’m ready to enjoy a healthy and safe pregnancy diet.