Iron deficiency is one of the most common nutrient shortfalls in the UK, particularly among women and teenage girls. Now new research has uncovered another group of people that are at risk, fitness and exercise enthusiasts.
The study that will be publicised in Network Health Dietitians shows how the body uses this important micronutrient and explores how easily iron deficiency can erode stamina and sporting performance.
It reveals that just over a third of female athletes have such low levels of ferritin (a marker of iron stores) that they may be at a high risk of clinical anaemia. Three out of five female athletes are ‘depleted’ in iron which means their ferritin levels are low enough to be at the first stage of developing deficiency. In general, having a low iron status, indicated by low ferritin or transferritin levels in the blood, increases the risk of iron deficiency, which may lead to other problems such as tiredness, hair loss and shortness of breath.
Lead author, dietitian and member of the Meat Advisory Panel Dr Carrie Ruxton, says: “It’s seems that many fitness regimes are missing a vital ingredient — iron — and all the evidence confirms that without healthy iron levels it is unlikely that any athlete will achieve their full potential.
“While the studies focus on elite athletes, our research suggests that lack of iron is probably affecting the performance and potential of thousands of everyday exercise enthusiasts. At a minimum, athletes should ensure their diets contain at least the Reference Nutrient Intake for iron.
“The simplest way to achieve this is to eat red meat because the haem iron in meat is much more available to the body and readily absorbed compared with the non-haem iron which comes from fortified foods and plant foods.”
In simple terms, it comes down to the balance between the oxygen demands of muscle being pushed to the limit, and the ability of our cardiovascular system to absorb and transport the oxygen needed to perform to the best of ones ability. Scientists and serious sportsmen and women know this as the equation VO2max — the gold-standard measure of cardio respiratory endurance and aerobic fitness.
Rin Cobb, co-author and clinical and sports performance dietitian adds: “A key goal for athletes to be able to perform to the best of their ability is to increase their VO2max score, but this is unlikely to be achieved without optimal iron levels because iron is essential for the production of haemoglobin, the body’s oxygen transport system.
“VO2 max is one of the key factors that determines exercise performance but this can be adversely affected by low iron status as it limits oxygen carrying capacity of the blood. You don’t have to be clinically iron deficient to experience this as low iron stores – found in up to 60% of female athletes – can also negatively impact on the transportation of oxygen, resulting in athletes no being able to perform to their best”.
The findings of the study are particularly important for new mothers who are exercising. Dr Carrie Ruxton explains: “We know that iron deficiency is common in women of child-bearing age while pregnancy and breastfeeding place huge demands on a woman’s iron stores. But now there is such intense pressure to shed baby-weight quickly that its becoming increasing popular for new mums to rush back to their work-out routines within days of giving birth and this can only add to the gap between iron requirements and intakes.”
Having a chronically low iron status increases the risk of iron deficiency, which may lead to problems such as tiredness, hair loss and shortness of breath.
Top meal tips for healthy iron intake:
- Eat foods rich in haem iron, such as red meat four to five times a week (up to 500g a week cooked weight)
- Drink fruit juice while intaking your red meat meal to help boost iron absorption
- Have green leafy vegetables with your red meat dish to enjoy an iron rich meal
Top tips for active individuals:
- Women who work-out a lot should ensure they have a sufficient intake of dietary iron and have their iron status checked regularly
- Ferritin levels below 35mg/L should be corrected to prevent full-blown anaemia
- Ensure you eat up to the weekly guideline of 500g of cooked red meat
Some more surprises from the study:
- Every day we absorb roughly the same amount of iron as we shed in dead skin
- On average 10-30% of the iron we eat is actually absorbed with haem iron around three times better absorbed than the iron found in plant foods or fortified products
- Inflammation and infection can have a negative effect on iron levels
- Low iron can lead to cognitive dysfunction, poor temperature control and weakened immunity
Source: Functional Sports Nutrition