Other Health Issues

Iron Deficiency Anemia

Anemia is a very common illness affecting people of all ages, with iron deficiency anemia being its commonest variety. Without enough iron, the body cannot produce enough hemoglobin, a substance in red blood cells that transports oxygen to various tissues and organs.

Causes:

  Inadequate iron intake from diet

  Poor absorption. Most of the dietary iron is absorbed in the upper small intestine. Any abnormalities in the gastrointestinal tract (GI tract) can affect iron absorption and cause iron deficiency anemia.

  Blood loss. Iron is lost along blood our body loses from whatever causes. As an example, heavy menstrual flow in women of reproductive age may lead to excessive blood loss. Alternatively, slow but chronic blood loss in the GI tract from long-term use of aspirin and NSAIDs (non-steroidal anti-inflammatory drugs), peptic ulcers, inflammatory conditions of the bowel, piles and polyps, or even cancerous growths can also lead to iron deficiency anemia.

At risk groups:

  Children and adolescents in stages of rapid growth and pregnant women: due to an increased iron requirement and red blood cell production associated with these body changes.

  Women of reproductive age: due to blood loss in menstruation

  Elderly people: due to poor intake and various chronic illnesses.

  Vegetarians. Meat and seafood are rich sources of iron and people who do not eat these foods are prone to develop iron deficiency anemia.

  Frequent blood donors. Iron deficiency related to blood donation tends to be a temporary problem and can be reversed by eating more iron-rich foods.

Symptoms:

Mild cases may have no symptoms but moderate to severe cases may have symptoms such as tiredness, low exercise tolerance, poor appetite, breathlessness, palpitation or chest pain, and dizziness or headache.

Other symptoms include a sore tongue, brittle nails, craving to eat non-food items like paper or ice (pica), and restless legs syndrome which is a sleep disorder.

Health Impacts:

  In its mild form, iron deficiency anemia may go undetected and pose no major health risks. However, severe cases can have the following outcomes.

  Heart problems. Palpitation, as the heart needs to pump harder to make up for the decreased oxygen carrying capacity of the blood. This could ultimately lead to heart failure.

  Problems related to pregnancy. Iron deficiency anemia is more likely to give rise to premature birth and low birth weight in the newborn.

  Growth problems. Iron deficiency anemia can compromise the growth and development of children.

  Lack of iron affects the immune system and increases the risk of illness and infection.

How to prevent:

Eat iron-rich foods. Meat, eggs, seafood, dark green leafy vegetables, dried fruits, beans and peas are rich sources of iron. Of note, the haem iron in meat and seafood is much more easily absorbed by the body. To enhance the absorption of non-haem iron in plant foods, serve food rich in vitamin C, e.g. oranges, lemons, limes, grapefruit, kiwi fruit, tomatoes, broccoli, etc. alongside the iron-rich foods.

Tea and coffee hinder iron absorption. Avoid these drinks 1 to 2 hours after meals.

Treatment:

Treat the underlying causes

Eating an iron rich diet and taking iron supplements are the mainstay of treatment

If you suspect you have iron deficiency anemia, always seek advice from your doctor as it is not something to self-diagnose or treat on your own with over-the-counter iron supplements. In fact, iron tablets can affect the absorption of other nutritional minerals and cause gastrointestinal discomforts, apart from the potential to interact with some medications. In severe cases, excessive intake of iron over time can lead to major organ failures or even death.

The recommended daily requirement of iron is as below:

Age Recommended daily requirements (mg)
Male Female
4-6 10 10
7-10 13 13
11-13 15 18
14-17 16 18
18-49 12 20

Iron-rich food

1.

Meat and seafood

  • Beef, pork, lamb, etc.
  • Oyster, shrimp, clam, etc.

Note: Medical research have revealed that eating too much red meat (beef, pork and lamb, etc.) would increase the risk of colon cancer. World Cancer Research Fund recommended to eat less than 500g red meat (cooked) per week.
2.

Egg, dried beans and its products

  • Egg
  • Soybeans, lentils, red kidney beans, soybean milk film, etc.
3.

Dried fruits

  • Raisins, dried apricots, etc.
4.

Nuts, seeds

  • Cashew nuts, sesame, peanuts, etc.
5.

Vegetables

  • Spinach, wood ear fungus, etc.
6.

Grains

  • Brown rice, oats, etc.
  • Breakfast cereals fortified with iron

 

   
   

Iron content of food

Food Weight Iron (mg) Food Weight Iron (mg)
Beef (round) (cooked) 100 g 2.6 Adzuki beans (cooked) 1 cup*
( 230 g )		 4.6
Pork (loin) (cooked) 100 g 1.2 Lentils (cooked) 1 cup (198g) 6.6
Lamb (leg) (cooked) 100 g 2.2 Cashew nuts 1 oz.
( 28 g )		 1.7
Chicken (thigh) (cooked) 100 g 1.3 Sesame 1 Tbsp
( 9 g )		 1.3
Tuna fish (canned in water) 100 g 1.5 Peanuts 1 oz.
( 28 g )		 1.2
Clams (cooked) 100 g 27.9 Raisins 0.5 cup
( 72 g )		 1.3
Oysters (cooked) 100 g 9.2 Apricots (dried) 0.5 cup
( 65 g )		 1.7
Shrimps (cooked) 100 g 3.0 Date (dried) 100 g 2.3
Egg (boiled) 1 piece
( 50 g )		 0.9 Spinach (cooked) 1 cup
( 180 g )		 6.4
Soybeans (cooked) 1 cup
( 172 g )		 8.8 Wood ear fungus (soaked in water) 100 g 5.5
Red kidney beans (cooked) 1 cup
( 171 g )		 5.0 Brown rice 1 cup
( 195 g )		 1.0
Chickpeas (cooked) 1 cup
(164 g )		 4.7 Oat bran,
breakfast cereals		 0.5 cup
( 40 g )		 1.8
Soybean milk film (dried) 100 g 16.5 Oats (cooked) 1 cup
( 234 g )		 2.1

*1 cup is approximately 240ml


Reference:
1) The Chinese Dietary Reference intakes (2013)
2) Centre for Food Safety Nutrient Information Inquiry System
3) Hong Kong Red Cross blood transfusion service
4) Anaemia: A Public Health Problem Worth Attention. Non-Communicable Diseases Watch, July 2019, chp.dh.hk

(Revised in November 2023)

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