5 Essential Vitamins: Iron, Zinc, Vitamin A and More

Learn a​bout 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).​​​

Iron – Essential 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: Red 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 likelihood of multi-organ damage
Overdose symptoms: Vomiting and diarrhoea

​​​Iron<span id='ms-rterangeselectionplaceholder-end'></span>


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: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: Diarrhea, 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

Original article at: https://www.healthxchange.sg/food-nutrition/supplements/five-essential-vitamins-iron-zinc-vitamin-a

Photo credit: original website.

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