Did you know that drinking tea can severely inhibit your body's ability to absorb vitamins and minerals - especially iron?
Lets learn a little more about tea. It can be categorised into three main groups, each of which have very different properties:
- Black tea
- Green tea
- Herbal tea
Black tea - high in tannins and caffeine
- Consists of teas such as English Breakfast, Earl Grey etc - i.e. the common British staple tea such as PG tips, Twinings, Tetley etc.
- Black tea contains the most tannins and caffeine of the tea types.
Green tea - low in tannins and caffeine
- Very popular in Asian countries and increasingly so in Europe and America due to its antioxidant and fat-burning properties.
- Green tea contains little or no tannins and less caffeine than black tea, but contains high amounts of a polyphenol antioxidant called EGCG.
Herbal tea - normally no tannins or caffeine
- Herbal tea isn't really made from tea (which is a specific kind of plant), it is really just an infusion of leaves, seeds, roots or bark, extracted in hot water.
- Varieties include ginger, ginkgo biloba, ginseng, hibiscus, jasmine, rosehip, peppermint, rooibos (red tea), chamomile, and echinacea.
- Herbal teas each normally have their own 'medical' reason for being drunk e.g. peppermint/ginger for digestion and bloating, chamomile for insomnia, rosehip/rooibos are high in vitamin C and antioxidants which are good for your skin and immune system.
The effects of caffeine
Caffeine inhibits Vitamin D receptors within your body, which limits the amount absorbed when you take supplemental forms such as Vitamin D3. Reduced Vitamin D levels affect the absorption and use of calcium in building strong bones. Caffeine is also diuretic which causes you to urinate more frequently, flushing out water-soluble vitamins such as the B-Complex vitamins and Vitamin C. Caffeine significantly reduces the absorption rate of Iron in your intestines - believed to be up to 80%.
Summary: Black tea and Green tea stop efficient absorption of Iron, Vitamin D and B-Complex vitamins.
The effects of tannins
Tannins are a type of polyphenol found in plants, fruits and vegetables and have a bitter taste. They are responsible for the bitter taste in black tea, red wine and unripe fruits, it is this bitterness which is believed to protect plants, fruits and vegetables from being eaten by insects and plant predators.
Tannins don't effect the absorption of vitamins, but they do bind (chelate) to iron and block its absorption into the body from your intestines.
Summary: Black tea stops efficient absorption of Iron.
The effects of EGCG
EGCG has been found to bind to iron in the intestine, preventing its absorption - instead simply being excreted out. Iron is necessary to carry oxygen from the lungs throughout the body and for other cell functions.
Summary: Green tea stops efficient absorption of Iron.
Why is Iron so important in the body?
Most of the Iron in the body is found in the haemoglobin of red blood cells. Iron helps red blood cells deliver oxygen from the lungs to cells all over the body. Once the oxygen is delivered, iron then helps red blood cells carry carbon dioxide waste back to the lungs to be exhaled. Iron also plays a role in many important chemical reactions in the body.
Low levels of Iron result in Iron deficiency anaemia. In people with Iron deficiency anaemia, the red blood cells can't carry enough oxygen to the body because they don't have enough Iron. People with this condition often feel very tired.
Taking vitamin and iron supplements with black and green teas is best avoided and you should wait at least an hour to eat or take any supplements if you are a tea or coffee drinker. Drinking tea and coffee can significantly inhibit the absorption of Iron by your body.
Some herbal teas however, such as rosehip or thyme are high in Vitamin C which actually enhances the absorption of iron.