If you're in one of the groups below AND your blood test results show low ferritin, low serum iron, low transferrin saturation, low haemoglobin (not necessarily all of those at once), then you need to be aware of possible IRON DEFICIENCY.
Women - menstruation, pregnancy, and lactation
Teenage females - menstruation, poor dietary choices, rapid growth
Infants - high iron requirements
Athletes - iron loss in sweat and urine
Vegetarians and Vegans - low iron intake from food (exacerbated by menstruation in female vegetarians/vegans)
Elderly - poor diet, reduced gut function, blood loss associated with haemorrhoids, bleeding ulcer etc
Besides the lab results, you will usually feel pretty crap ...
Tired, dizzy, lightheaded, headaches
Lowered immune function so you're more prone to infections
Brain fog, poor concentration, irritability
Slowed growth and development in infants, poor appetite
Rapid or irregular heartbeat (these can be associated with other conditions, so please consult your GP)
Premature births and low birth weight babies.
What can you do?
Well, if you're not a veggo then eat more red meat, pork, poultry, seafood but non-animal eaters can benefit from legumes (esp chickpeas and black eyed peas), tofu, tempeh, seeds (esp pumpkin, sesame, hemp, and flaxseeds, nuts (esp almonds, cashews, pine nuts and macadamias) and iron-fortified foods.
Supplements are an option but I recommend 6 monthly blood tests as you may not need to continue supplementing if your levels return to normal (keep in mind some conditions are better treated with high of end normal readings of iron such as in Restless Leg Syndrome).
Please be aware that some forms of iron are either not well absorbed or not well tolerated (or both). I never recommend ferrous sulphate (eg Ferro-Grad, the one most people are advised to take), as up to 70% of people report gut side effects such as constipation, nausea, or diarrhoea.
Iron biglycinate is my preferred organic form of iron as it is well tolerated and in a randomised trial reported in the Journal of Perinatal Med (2014), 25 mg of iron biglycinate was as effective as 50mg of ferrous sulphate.
So if you're feeling very fatigued, fighting infections more often, feeling foggy in the head, and are in a risk group, then check your levels with a blood test, see if there are more foods you can include in your diet, and consider an iron supplement that is in the biglycinate form.