Continued from previous page.

Mr Johnathan Diong, Senior Pha​rmacist from the Department of Pharmacy at Singapore General​ Hospital (SGH), a member of the SingHealth​ group, shares five essential vitamins and why they are good for you.

Iron – Es​sential for boostin​g 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: Re​d m​eat 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 like​liho​od 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 A<span id='ms-rterangeselectionplaceholder-end'></span>

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

Vitamin C

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
F​ood 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​.​

Ref: U11​

Check out our other articles on vitamins:

Vitamin A: Benefits and Best Food Sources

Vitamin B: Why Your Body Needs It

Vitamin B: Signs of Deficiency

Vitamin C: Benefits and Top Food Sources

Vitamin D: Food Sources, Supplements and Side Effects

Antioxidants: How It Helps the Body

Antioxidants and Cancer Prevention