Vitamins and supplements : How much is too much

Changing food habits, rising consumption of convenience and processed foods, and lifestyle factors as well as practices like stress, smoking, alcohol consumption, etc, seriously impact the nutrition in our diet, creating a nutritive imbalance and/or affecting the absorption of many vital nutrients and vitamins in our body.

Many people are turning to vitamin supplements to overcome these deficiencies — sometimes perceived, usually without medical advice or awareness about the actual requirement and proper dosage. “A normal healthy diet is able to meet the body’s nutritional requirements,” says Dr Vishal Sharma, gastroenterologist, PGIMER, Chandigarh. However, there are certain situations when the body is not able to absorb nutrients from the diet.

Appetite and nutrient absorption decreases after 50, or during pregnancy and lactation, diabetes, cancer, pancreatic disorders and liver diseases. Bone density also decreases with age, so calcium and vitamin D requirement is more as you age. Those who are vegan or follow fad or restrictive diets will also have nutritional imbalance and need supplementation, adds Dr Sharma.

Noida-based Dr Sushrut Singh, gastroenterology specialist at Fortis, says diabetics who take Metformin run the risk of vitamin B12 deficiency, particularly if they are vegetarians.

Doctors prescribe supplements only if there’s any deficiency, that too for a limited time. “Problems arise when people take supplements without medical guidance or continue taking these beyond the prescribed time,” says Dr Pawan Rawal, gastroenterologist, Artemis Hospitals, Gurugram.

Nearly 80 per cent Indians are deficient in vitamin D, with those below 25 most affected. “Vitamin D toxicity has increased after its test has become part of lab packages. I have come across many cases of overdose, where people were taking vitamin D injections/shots/supplements without prescription or taking it for years even though the doctor had prescribed it for a few months. Extreme cases required hospital admission and dialysis as vitamin D toxicity causes hypercalcemia (very high levels of calcium in blood), which can cause kidney failure and/or sudden cardiac arrest,” says Dr Ajay Agarwal, director, internal medicine, Fortis, Noida.

Vitamins are of two types — water soluble (all B vitamins and vitamin C) and fat soluble (vitamins A, D, E and K). In case of minor excess, water soluble ones are excreted through urine. The problem of over-dosage can arise in case of fat-soluble vitamins as these get deposited in the fatty tissues of the body, says Dr Seema Dhir, internal medicine specialist, Artemis Hospitals, Gurugram.

Diet-based nutrition is the safest as chances of overdose of any vitamin or mineral through natural sources are remote, says Mohali-based nutritionist Neelu Malhotra. “Targeted supplements sometimes may not be tolerated as well as natural ones, which are absorbed better by the body. Multivitamins can also interfere with other medications and/or with the absorption of other nutrients. Iron supplements when taken even by anaemics usually cause digestive issues,” she adds. Pregnant women should only take supplements and dosage as medically advised because an over-dose of some vitamins, such as vitamin A, can affect embryo development.

Experts agree that there is no data to suggest any benefits of taking multivitamins, particularly if there’s no deficiency. Even when prescribed, they suggest taking only for the recommended period. However, those who still feel compelled, they advise taking supplements for a short period with long breaks in between. But the bottomline remains a healthy and balanced diet.

Vitamin A

Overdose symptoms Nausea, abdominal pain, dry skin, eyes, cracked lips. Extreme case: Increased intracranial pressure, coma, death

Sources Liver, whole milk, butter, yellow, green, red fruits & vegetables.

Recommended daily allowance (RDA) 700-900 mcg

Upper limit 3000 mcg

Vitamins B

Overdose symptoms Skin rash, insomnia, gastrointestinal issues, numbness, hypertension or hypotension

Sources Lean meat, fish, egg, cereals, green vegetables, pulses, liver

RDA Vitamin B1, B2, B6 (1.2 mg), B3 (16 mg), B7 (30 mcg), B9/folate (400 mcg)

Vitamin B12

Overdose symptoms Vomiting, diarrhoea, fatigue, tingling sensation in hands and feet

Sources Meat, fish, egg, milk and dairy foods

RDA 2.4 mcg

Upper limit Not established

Vitamin C

Overdose symptoms Nausea, diarrhoea, stomach cramps. Extreme case: Kidney stones

Sources Citrus fruits, strawberries, capsicum, cabbage, tomatoes, potatoes with skin

RDA 90 mg

Upper limit 2000 mg

Vitamin D

Overdose symptoms Vomiting, fatigue, frequent urination, bone pain. Extreme case: Kidney problems, cardiac arrest

Sources Milk, oily fish, egg yolk, exposure to sunlight

RDA 600 IU (international units)

Upper limit 4000 IU

Vitamin E

Overdose symptoms Muscle weakness, fatigue, nausea, diarrhoea. Extreme case: Blood thinning, internal bleeding

Sources Vegetables, cereals, egg, vegetable oils like soya oil, nuts

RDA 33 IU

Upper limit 1100 IU

Iron

Overdose symptoms Black (possibly bloody) stools, diarrhoea, liver damage (may occur several days after the ingestion), metallic taste in mouth, vomiting blood

Sources Red meat, seafood, liver, whole grains, seeds, legumes, beans, leafy greens

RDA 19 mg (men), 29 mg (women)

Upper limit 40-45 mg

Calcium

Overdose symptoms Vomiting, constipation, confusion, lethargy, weak bones and pain, kidney stones. Extreme case: Palpitations, fainting, cardiac arrhythmia (irregular heartbeat)

Sources Milk and dairy foods, green leafy vegetables, fortified cereals and foods

RDA 1000 mg

Upper limit 2500 mg

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