Have you ever considered how an innocent cup of black tea might be contributing to your fatigue?
Low level anaemia is very common and the symptoms of tiredness and fatigue are familiar to many so making the best use of the iron in our diets is important.
Several food compounds can interfere with the absorption of iron in our diets such as phytates which are interestingly found in many foods that provide a source of iron, and tannins which negatively affect iron absorption.
Tannins are a substance found in several plants and are known to be particularly concentrated in black tea. A number of studies (1-3) have shown that tannins bind to iron in the digestive tract preventing its absorption. This reaction happens to the non-animal forms of iron in our diet – the type we generally eat more of. These studies show that by having a cup of tea with your meal, or shortly before or after your meal, you can lose up to 60% of the available iron in that meal. For a nation of tea drinkers, with more people preferring a vegetarian or vegan diet, this is an important consideration.
So whilst tea has some really excellent antioxidant heart protective qualities it should be taken in moderation away from your main meals. A good practice, endorsed by recent results from a controlled clinical study (4) published in The American Society for Nutrition, is to leave an hour prior to and after your main meal, before having a cup of tea. If you feel you need something warm following a meal, consider switching to a glass of warm water and with a squeeze of lemon, this could actually improve your iron absorption, read on.
Iron from food takes two forms, haem iron that comes from meat and animal products, and non-haem iron that comes mainly from leafy green vegetables, beans, nuts, seeds and fruit. Generally we eat more non haem iron in our diets but this form is not as readily absorbable in our digestive tract than animal forms of iron. Non-haem iron requires an acidic environment to become what is called bioavailable and absorbable. Making and adding a simple fresh lemon juice dressing to your meal works well to help absorb your full quota of this precious mineral.
Lean steak, mussels, liver and liver pate, salmon, eggs, prawns, tuna and chicken are all good sources of haem iron and good sources of non-animal, non-haem iron, include figs, apricots, almonds, sesame seeds (humus), sunflower seeds, broccoli and spinach.
Iron supplements include differing forms of iron. Ferrous iron is one of the more gentle forms and easily absorbed into the small intestine. Ferrous fumarate has the best absorptive qualities over other forms such as sulphate or gluconate, this is an important aspect as less can be used to better effect, and when iron is known to be oxidative by nature this is an important consideration.
Supporting vitamins important to iron metabolism include vitamin C which enhances the absorption of iron, vitamin B12 (methylcobalamin) and folate which supports the growth and development of red blood cells. Those that may be low in B12 from a vegan diet could benefit from a vegan B12 supplement which would help the body use its supply of iron.
Lactobacillus probiotics also support the gut environment, increasing the availability of iron absorption through their effect at reducing compounds found in tannins.
Some common health problems are related to iron deficiency anaemia such as reduced digestive function shown through the symptoms of changes in the gastric bacterial environment, where gas and bloating occurs after eating. In this situation low levels of the normally abundant friendly lactic acid organisms within our gut can have an effect on iron absorption, this often occurs after taking antibiotics. Also deficiencies in other nutrients which, when low, reduce our red blood cell health and capacity to carry iron. There is also the possibility of inflammatory conditions within the digestive tract from conditions such as IBS, Crohn's, Colitis and Coeliac disease.
If you would like help selecting the right iron supplement or want to get to the bottom of digestive problems that may be affecting your iron absorption please contact Henley Nutrition.
This blog was written by Christine Lewis, Nutritionist and Naturopath at Henley Nutrition, November 2020.
(1) Brune, M. Rossander, L. Hallberg, L. (1989) Iron absorption and phenolic compounds: importance of different phenolic structures. | Semantic Scholar
(2) Disler, P. et al., (1975) The effect of tea consumption on iron absorption. BMJ. 193.full.pdf (bmj.com)
(4) Salma, F. A. et al (2017) A 1-h time interval between a meal containing iron and consumption of tea attenuates the inhibitory effects on iron absorption: a controlled trial in a cohort of healthy UK women using a stable iron isotope - PubMed (nih.gov)