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When it comes to vitamins and minerals, moderation is key.
Vitamins A, C and E are known as antioxidants that can help prevent cancer. But taking excessive amounts of vitamin C can cause diarrhoea, or worse, kidney stones. Similarly, too much vitamin A can lead to serious health risks, including damage to the liver. This is because the body absorbs some vitamins - such as A and E - and minerals only slowly. Taking more than the daily recommended levels can lead to a steady buildup of these substances in the liver and fatty tissues, which increases the risk of reaching toxic levels.
Water-soluble vitamin C is flushed out of the body when too much is consumed. “Even so,” said Mr Johnathan Diong, pharmacist, Department of Pharmacy, Singapore General Hospital, “it can be harmful in a normal healthy individual when taken at very high doses over a long period.” Vitamins and minerals play different roles in the proper growth and functioning of the body.
Vitamin C, present in fruits and vegetables, is a basic ingredient for beauty and promotes wound healing, Mr Diong said. Someone who doesn’t get enough vitamin C may suffer from bleeding gums and frequent bruising. Vitamins C and E - found in nuts and oils, green leafy and root vegetables - boost the body’s natural antioxidants to help mop up excess free radicals which can hasten ageing and cause cancer.
Calcium and phosphate are crucial for bone formation, while iron is essential for the production of red blood cells. Vitamins and minerals are present naturally in the foods we eat. Thus, eating a balanced meal with a wide variety of fresh meat, grains and vegetables ought to supply the body with all the vitamins and minerals it needs. But long hours at work and the convenience of takeout meals mean more people are not getting their full recommended daily dose of vitamins and minerals. “With our busy work schedules, I wonder how many of us are able to meet the Health Sciences Authority’s recommendation to consume two portions each of fresh fruits and vegetables a day,” said Mr Diong.
In such cases, taking a daily multivitamin can help ensure nutritional requirements are met. A multivitamin tablet contains sufficient vitamins to prevent and correct nutrient deficiency, but does not provide the full daily requirement. For instance, it does not contain sufficient calcium to meet the US recommended daily allowance of 1,000mg of elemental calcium for an average adult. Many people have started to take a variety of vitamins and minerals in the belief that large amounts of supplements can help delay ageing, prevent disease as well as enhance mental or physical abilities.
Although what is consumed may fall below the upper limit of tolerance for that particular mineral or vitamin, problems arise when vitamins and minerals are taken in excess over a long period. As with all good things, moderation is the key to maintaining a strong and healthy body.
 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 |
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