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Don’t overdo vitamins & minerals

Don’t overdo vitamins & minerals
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First Published: Wed, Mar 18 2009. 09 32 PM IST

Updated: Wed, Mar 18 2009. 09 32 PM IST
The discovery over the last couple of centuries of the importance of micronutrients (minerals and vitamins) and the fact that they can be artificially added to the human diet remains a major health care breakthrough.
Of late, however, researchers have discovered that micronutrients in macro doses can make you ill—literally. But the continuing discovery of the glories of micronutrients (see KNOW) means many of us pop over-the-counter (OTC) multivitamins “just to make sure” or hand children multi-fortified glasses of milk, even as researchers say they don’t help most people much after all (see UNLEARN and AVOID).
Ashutosh Shukla, head of the medicine department, Artemis Health Institute, Gurgaon, recalls a 40-year-old, New Delhi-based professional who had been taking two-three vitamin A capsules daily for three months or so, resulting in elevation of liver enzymes, dry skin and brittle hair. It could have been worse (see VITAMIN A). He notes that women worried about bone loss (osteoporosis) sometimes take vitamin D supplements arbitrarily and adds that many overweight people have been found to take multivitamins too often. Says Dr Shukla, “The pills include vitamin B1, thiamine, which has been found to open up your appetite, leading to...weight gain. The RDA of thiamine is only 1.4mg; most multivitamins contain much more.”
The take-home message is actually pretty simple: Supplementation is no substitute for good nutrition. A daily multivitamin and maybe an extra mineral supplement can make you healthier—if you are unable to meet your needs through your diet or belong to certain special categories, namely if you are pregnant or breastfeeding, suffer from certain diseases or disorders, are elderly or newborn or especially athletic.
Too much of some commonly supplemented micronutrients (vitamin A, vitamin D, iron) can even interfere with other medication and nutrients. The bottom line:
• Do not self-diagnose. Leave it to your doctor to prescribe supplements.
• Whenever a new supplement or medicine is prescribed, alert your doctor to all the pills you are already taking to avoid toxic or self-defeating combinations.
• When reporting your diet and medication, mention all supplements and any fortified foods (such as cereals, juices or milk) to make sure your doctor gets the whole picture. However, don’t stop taking one without checking either.
Get your daily dose
Vitamin A
Liver, full-fat dairy products, spinach, broccoli, tomato juice, peppers,
mangoes, dried apricots, carrots, sweet potatoes and pumpkins.
Vitamin D
Oily fish (salmon, sardines, tuna, mackerel, trout), dairy products and eggs. Also exposure to sunlight.
Vitamin E
Broccoli, nuts, soya beans, spinach and eggs.
Vitamin C
Citrus fruits and juices, kiwi fruit, strawberries, blueberries, tomatoes
and peppers.
Vitamin B complex
Vitamin B1: Whole grains, flour and bread and green leafy vegetables
Vitamin B2: Eggs, liver, milk and cheese
Vitamin B3: Protein-rich foods such as meat, liver and peanuts
Vitamin B5: Chicken, eggs and broccoli
Vitamin B6: Fish, chicken and wholegrain cereals
Vitamin B9: Raw fruit as well as yeast and liver
Vitamin B12: Fish, dairy produce, meat and yeast extract
Folate
Leafy green vegetables (such as spinach and turnip greens), fruits (such as citrus fruits and juices), dried beans and peas are all natural sources of folate.
Zinc
Oysters, beef, liver, seafood, poultry, nuts and seeds, whole grains, tofu
and legumes.
Iron
Wholegrain cereals, pulses, fish, turnip greens, watermelons, dried dates and blackcurrants. Non-vegetarian sources include meat, eggs and liver.
Calcium
Dairy products, leafy green vegetables, nuts and seeds (almonds, brazil nuts, sesame seeds), tofu and dried fruit.
*********
CALCIUM
Yes, it’s the stuff holding your skeleton together, but too much can be too hard on your health.
The trouble with too much:Overly high calcium intake can result in hypercalcaemia (elevated levels of calcium in the blood), impaired kidney function, a tendency towards kidney stone formation and decreased absorption of other minerals. People who are immobilized (say, because of a fracture) should be especially careful as they may be at increased risk of kidney stone formation.
At loggerheads with:Certain heart medicines, thiazide diuretics, glucocorticoids and aluminium or magnesium-containing antacids. It also impedes the absorption of synthetic thyroid hormone replacements.
Good to know: The body can only absorb a limited portion of the ingested calcium at a given time. If your doctor does suggest a supplement, it is better to spread your doses across the day (up to 500mg each time) along with meals to ensure better absorption. Drink water with it to avoid constipation. Also note that a calcium citrate supplement is better absorbed and digested by the body than other forms.
VITAMIN A
It’s actually not easy to be deficient in vitamin A with a reasonably balanced diet. Healthy adults usually have a reserve of vitamin A stored in their livers and are not at risk of deficiency, even if they have less fat in their diets temporarily. Problems, even in young children, are usually seen in those living near or below the poverty line, with inadequate health care and immunizations. On the other hand, toxicity can be quite painful and the effects long-drawn.
The trouble with too much:Large amounts of vitamin A are clearly toxic and may cause hair loss, joint pain, nausea, bone and muscle soreness, dry and flaky skin, rashes, enlarged liver and spleen and cessation of menstruation.
Good to know: Vitamin A needs fat in order to be absorbed properly. Taking vitamin A supplements with fatty foods (say, with milk rather than water) helps absorption.
VITAMIN C
While an essential nutrient, vitamin C is also one of the easiest things to get from your diet: Just eat enough fruits and vegetables (a serving each of five kinds). It isn’t likely to be directly toxic, but an excess can exacerbate certain health problems.
The trouble with too much: Gout patients could end up having greater problems with uric acid build-up in the presence of excess vitamin C. Those with sickle-cell anaemia have more fragile red blood cells which vitamin C can break apart, so people with this inherited condition should not consume it in large doses.
Chewable vitamin C tablets can erode tooth enamel if taken on a regular basis. Vitamin C can also interfere with glucose tests since these two compounds have similar chemical structures. Large amounts of vitamin C can also cover up the presence of blood in the stool, distorting the results of tests designed to detect colon cancer.
Good to know:Because vitamin C is better absorbed in the presence of flavonoids, many supplement manufacturers also add flavonoids to their formulas.
IRON
You can’t really breathe without it, since it is iron that lets the haemoglobin (the red pigment) in your blood bring oxygen from your lungs to all your cells.
A recent report on food insecurity in rural India by the MS Swaminathan Research Foundation and the UN’s World Food Programme noted an increase in the prevalence of anaemia in the country. But anyone on a reasonably healthy diet should have no reason to worry...or supplement the diet.
The trouble with too much:Iron overload is a condition in which excess iron builds up in the blood and is stored in organs such as the liver and heart. It is associated with several genetic diseases, including haemochromatosis (sufferers absorb iron a little too efficiently, resulting in organ damage such as cirrhosis of the liver and heart failure) and blood disorders that require frequent blood transfusions, but excessive supplementation could result in similar toxicity.
At loggerheads with:Some cholesterol and BP lowering medications, ACE inhibitors, tetracyclines, birth control and thyroid replacement hormones. For this reason, it is best to take iron supplements at least 2 hours before or after medication.
Good to know: Iron supplements are best absorbed on an empty stomach (better for thwarting interference with other nutrients or medication). However, it leads to stomach upsets for some. If this is the case, take it with food, or half an hour after a meal.
ZINC
Essential for healing and immunity, growth and reproductive health, zinc is not a nutrient whose deficiency is very common, though marginal deficiencies are not easily noticed either, since they may be expressed as low immunity and fatigue. It is also used in cold lozenges. This, however, doesn’t imply that taking lots will cure every cold and guarantee fatigue-free days for all! An excess can be distinctly unpleasant, which is why zinc supplements (typically zinc sulphate) should be prescribed only when there is good evidence of deficiency.
The trouble with too much: Zinc toxicity can occur in both acute and chronic forms. Acute adverse effects of high zinc intake include nausea, vomiting, loss of appetite, abdominal cramps, diarrhoea and headaches. Excess zinc disrupts iron metabolism and may also decrease magnesium and calcium intake, compromise immunity and reduce levels of HDL (high-density lipids or “good cholesterol”).
At loggerheads with: The quinolone and tetracycline groups of antibiotics, which interact with zinc in the gastrointestinal tract, inhibiting the absorption of both zinc and the antibiotic. Zinc can also reduce the absorption and action of penicillamine, a drug used to treat rheumatoid arthritis.
Good to know: Zinc supplements are best taken before bedtime and at least 8 hours after any iron supplement. If you are taking them with antibiotics, taking the antibiotic at least 2 hours before or 4–6 hours after taking a zinc supplement minimizes the clash.
FOLATE
Pregnant women, new mothers, and young babies need extra folate so check with the doctor about a supplement. But this is another mineral whose deficiency is unlikely with a normal diet. Thankfully, toxicity is unlikely too as this water-soluble vitamin is readily excreted in urine; but there are good reasons for caution.
At loggerheads with: Vitamin B12, in that an excess of folic acid can trigger symptoms of vitamin B12 deficiency and, in turn, permanent nerve damage can occur if the deficiency is not treated. So, especially if you are 50 or older, ask your physician to check your B12 status before you take a supplement that contains folic acid. If you are taking a supplement containing folic acid, read the label to make sure it also contains B12 to make up for the antagonism.
Good to know: Taking folic acid along with vitamin B12 may increase the risk of vitamin B12 deficiency. Caution is advised when taking these vitamins together.
CONNECT
KNOW
Recent research from Johns Hopkins University suggests vitamin D decreases your likelihood of dying: Deficiency increases your risk of death by 26%, while vitamin D decreases mortality rate from almost every type of cancer, including breast, colon and prostate. Research also suggests that it helps prevent diabetes, kidney and cardiovascular diseases. People deficient in vitamin D may experience muscle pain or aches. The sun helps you produce vitamin D. To increase your dietary intake, eat salmon and tuna, fortified cereals, nuts, orange juice and dairy products.
©2009/THE NEW YORK TIMES
UNLEARN
Many postmenopausal women take multivitamins in the belief that these help prevent cardiovascular disease or cancer, but a new study has found they do neither (previous studies had mixed results). The findings were published in February in ‘The Archives of Internal Medicine’. Researchers followed 68,132 women for eight years on average to track the health effects of multivitamins. After controlling for age, physical activity, family history of cancer and other factors, they found the supplements had no effect on the risk of breast, colorectal, endometrial, lung or ovarian cancer, heart attacks, strokes, blood clots or mortality. Lead author Marian L. Neuhouser, a nutritional epidemiologist at the Fred Hutchinson Cancer Research Center in Seattle, US, says, “Buying more fruits and vegetables might be a better choice.”
©2009/THE NEW YORK TIMES
AVOID
About a third of children in the US between two and 17 years take a multivitamin (or other vitamin or mineral supplement) —but many do not need it, said a study published in February. Yet children who may benefit most from supplements, including those with poor health or diet, may be the least likely to take them, researchers said in the ‘Archives of Pediatric & Adolescent Medicine’. Ulfat Shaikh of the University of California Davis School of Medicine, the lead author, says many children taking supplements receive adequate nutrition from the foods they eat.
Reuters
Experts: Nalin Nag, consultant, internal medicine, Indraprastha Apollo Hospitals, New Delhi; Jyothi Prasad, chief dietician, Manipal Hospital, Bangalore; Ashutosh Shukla, head of the medicine department, Artemis Health Institute, Gurgaon
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First Published: Wed, Mar 18 2009. 09 32 PM IST