5 Essential Vitamins: Iron, Zinc, Vitamin A and More
Learn about the 5 essential vitamins and the symptoms of overdosing on them from Mr Johnathan Diong, Senior Pharmacist from the Department of Pharmacy at Singapore General Hospital (SGH).
and minerals are naturally present in the food we eat.
Continued from previous page.
Mr Johnathan Diong, Senior Pharmacist at the
Department of Pharmacy at
Singapore General Hospital (SGH), a member of the
SingHealth group, shares 5 essential vitamins and why they are good for you.
Iron – Essential for boosting the body’s immune system and an important component of many enzymes. Also functions as an antioxidant
US RDA: 8mg (men), 18mg (women)
Food sources: Red meat such as beef, oysters, shrimp, tuna, lentils, kidney beans and cashew nuts
Excessive intake: Slight excess causes constipation. Higher excesses may result in gastric mucosal ulceration, and increase the likelihood of multi-organ damage
Overdose symptoms: Vomiting and diarrhoea
Zinc – Essential for boosting the body’s immune system and an important component of many enzymes. Also functions as an antioxidant
US RDA: 11mg (men), 8mg (women)
Food sources: Red meat such as beef, oysters, milk, baked beans and chickpeas
Excessive intake: May result in copper deficiency
Overdose symptoms: Nausea and vomiting
Vitamin A - Essential for healthy skin, retina and mucous membranes
US RDA: 700mcg (men), 900mcg (women)
Food sources: Yellow and orange vegetables like carrots and pumpkins, spinach, sweet potatoes and cod liver oil.
Excessive intake: May be harmful to skin and bones, causing weakness and brittleness
Overdose symptoms: Tiredness, decreased appetite, vomiting, joint soreness, drying and cracking of lips and skin, hair loss and yellowing of the skin
Vitamin C - Helps form strong collagen fibres which are essential for the strength and integrity of connective tissue, bones, tendons and ligaments. Also acts as an antioxidant
US RDA: 90mg (men), 75mg (women)
Food sources: Fruits such as oranges, grapefruits and strawberries, vegetables like broccoli and tomatoes
Excessive intake: Increases the likelihood of calcium oxalate kidney stones and can deplete the body of copper, another essential nutrient
Overdose symptoms: Diarrhoea, stomach cramps and nausea
Calcium – Crucial for maintaining a normal heartbeat and for normal functioning of nerves and muscles. Acts as a building block for bones
US RDA: 1,000mg
Food sources: Dairy products such as milk, cheese and yoghurt, vegetables like broccoli and Chinese cabbage
Excessive intake: May impair kidney function and decrease absorption of other minerals
Overdose symptoms: Nausea, vomiting, loss of appetite and increased urination
See previous page to find out
why vitamins should be taken in moderation.