Every now and then, my teenage boys acknowledge my nutrition education, admit that I might actually know something they don’t and ask me for advice. This week, they were complaining of being utterly exhausted, beaten up by the hours of forceful football practice. They found themselves doubting they possessed enough energy to finish all of that evening’s studying, let alone hit repeat the next day. Four tips for losing weight, from adding vitamin B and omega 3 fats to your diet, to slower eating Of course, there is no elixir that I can whip up to magically give them a second wind or make them feel as refreshed as after a good night’s sleep. I might offer my children natural remedies they often think are wacky, but I am no witch doctor. I did suggest that they make certain they eat well during these long, tiring days and nights. I hinted that perhaps their choice to sleepwalk through breakfast, talk to their friends through lunch and rush through dinner might leave them without all of the nutrients – especially iron – that they need. Why iron? Iron equals energy. Iron’s main job is to help carry oxygen from the lungs to every cell in the body. Beware those sexy diet quick fixes, moderation is the way to go – how to achieve it, and five obstacles to success When you do not get enough oxygen to your cells, you are left feeling exhausted and weak. Iron deficiency is the most common nutritional deficiency worldwide, according to the World Health Organisation. It is the only nutrient deficiency which is also prevalent in industrialised countries. This is a significant public health concern in that even a mild iron deficiency can impair our lifestyle. Even if my guys are not actually iron deficient, giving their cells a little more oxygen certainly cannot hurt. Think about it: getting oxygen to our brains, muscles and heart surely sounds like it would help energise each of these body parts. In fact, if our cells do not get the oxygen they require, they start dying. Makes you want to breathe deeply, doesn’t it? The oxygen level in the brain greatly affects cognitive output; if the brain isn’t getting enough oxygen, it certainly isn’t going to be as sharp as it could. In fact, the brain uses 20 per cent of all the oxygen in the body, so iron’s job is vital. Athletic performance is also affected when we do not get enough iron, as muscles, too, require oxygen. Immune function and the ability to ward off colds are also affected when a body doesn’t have enough iron. Some juices sold in Hong Kong contain toxins found in decaying fruits, tests show Iron is integral to many enzyme functions, helping us digest foods and absorb nutrients. When we are able to access all of the protein, fats and carbohydrates from our meals, we have more energy and are healthier. Iron helps balance hormone levels, essential for any teenager. Iron also helps regulate metabolism and creates healthy skin, nails and hair. Although low iron can contribute to bruising, I am going to stick to the assumption that the bruises on my boys’ bodies are the result of too many tackles and not a lack of spinach. Kids and adults who drink caffeine may be depleting their bodies of iron. Caffeine inhibits iron absorption, making it hard for the essential mineral to get to our cells to work its magic. Digestive distress can also inhibit the absorption of iron. Excess exercise can damage red blood cells, the cells that carry the oxygen throughout our bodies, so the body may need even more iron when exercising to the extreme. Vegan dogs and cats in Hong Kong – how diet lowers pets’ carbon footprint and improves their health, according to owners Women need more dietary iron than men because they lose some through blood loss during menstruation. And anyone sticking to a vegetarian or vegan diet should focus on iron intake because vegetarian sources of iron are absorbed into the body differently. Heme iron, found in animal foods such as meat, poultry, fish, clams and eggs, is two to three times as usable as the non-heme iron found in plant foods such as beans, leafy green vegetables and nuts. If you are a vegetarian, the optimal way to get your iron is to combine leafy greens, beans and a food with vitamin C such as tomatoes or citrus. Vitamin C aids in all iron absorption. The recommended daily amount of iron is: Children aged four to eight: 10 mg. (This age group requires more iron than older children because of their rapid growth.) Children aged nine to 13 – 8mg. Boys aged 14 to19 – 11mg. Girls aged 14 to 19 – 15mg. Women aged 19 to 50 – 18mg. Men aged 19 to 50 – 8mg. If you want to boost your energy, make sure your meals look something like this: Breakfast : three scrambled eggs with whole grain toast and a cup of berries. Lunch : a bowl of meat-and-bean chilli with sliced avocado. Dinner : chicken, rice and sauté spinach. Taking an iron supplement is not ideal without a doctor’s supervision, as too much iron can be as dangerous as too little. Casey Seidenberg is co-founder of Nourish Schools, a Washington-based nutrition education company, and co-author of The Super Food Cards , a collection of healthy recipes and advice.