Cornell Expert warns against overdosing vitamins


Every day, millions of people around the world take vitamins and other forms of dietary supplements. While many believe that consuming vitamin supplements will benefit their health, consuming excessive amounts of any given compound could pose significant health risks.

And some of these supplements are sold in extra strength “mega-doses” — tens or hundreds of times the recommended daily amounts — which can increase the risks of taking too much.

“Vitamins or dietary supplements in mega-doses can be harmful to consumers,” said Rui Hai Liu, a professor in the Department of Food Science at Cornell University. Newsweek.

People with deficiencies of certain vitamins or minerals may benefit from taking relatively high doses of a given supplement for a limited period of time, although it is important to consult with a health care provider before implementing any supplementation protocol.

But in general, Liu said, “Don’t take mega-doses of vitamins or dietary supplements.”

Supplements are not intended to replace a healthy and varied diet. And experts like Liu recommend that people get their vitamins and antioxidants from food, not supplements, whenever possible.

Can you take too many vitamins?

Consuming high doses of some single-nutrient supplements or multivitamins can have potentially adverse health effects, depending on what is taken. Compounds that can be particularly problematic when taken in very high doses include vitamins A, D, C and B6.

“There are always possibilities for both acute and long-term adverse effects when supplementing with any substance, including vitamins,” Ginger Hultin, Seattle-based registered dietitian nutritionist, owner of Ginger Hultin Nutrition and author of the e-book Meal Prep for Weight Loss 101 -Told Newsweek.

“It’s important to know that taking any dietary supplement is generally safe when taken in the right doses, for the right reasons. It’s definitely worth working with a professional like a dietitian or primary care physician. remedy that can help you navigate the complexity,” she said. said.

There are two major groups of vitamins: fat-soluble and water-soluble. The body absorbs raw materials, which do not dissolve in water, such as dietary fats, storing them for long periods of time. The fat-soluble vitamins are A, D, E and K.

The latter group, on the other hand, dissolves in water and is readily absorbed by body tissues. The water-soluble vitamins are vitamin C, plus the B vitamins: B1, B2, B3, B5, B6, B7, B9 and B12.

Stock image: a woman holding dietary supplements. Vitamin supplements are generally safe, although some can cause health problems if taken in excess.

The body only uses the vitamins and minerals it needs, so excessive amounts will be excreted or, possibly, pose a risk of toxicity. Because fat-soluble vitamins are stored in the body, their toxic potential is higher because excessive intakes can accumulate more easily over time.

In general, taking large doses of water-soluble vitamins is less likely to cause health problems than taking fat-soluble vitamins because they are not stored. But sometimes taking megadoses of certain water-soluble vitamins can also be problematic.

“Fat-soluble vitamins can certainly become toxic at high levels, but so can water-soluble vitamins,” Hultin said. “A lot of people say, ‘It’s just expensive pee,’ which indicates that high doses of water-soluble vitamins don’t have any real effects on the body, but that’s not true.”

For example, very high doses of water-soluble vitamin C, an antioxidant that plays a role in immune function, can lead to various problems such as diarrhea, nausea, abdominal cramps and other gastrointestinal problems. The recommended daily allowance (RDI) for vitamin C is 90 milligrams for men and 75 milligrams for women, according to the National Institutes of Health.

A selection of dietary supplements
Stock image: A selection of dietary supplements. Supplements should not replace a healthy and varied diet, experts say.

Meanwhile, taking high doses of vitamin B6 over long periods of time can lead to serious health issues, including neurological problems, skin damage, and nausea. The recommended B6 RDI for both men and women is 1.3 milligrams. Research indicates that problems can arise when individuals consume 1-6 grams per day.

When it comes to fat-soluble vitamins, regular consumption of large amounts of vitamin A can lead to a very rare condition known as hypervitaminosis A, the symptoms of which include nausea, vomiting, increased pressure on the brain, abdominal pain, drowsiness and irritability. . In extreme cases, hypervitaminosis A can even lead to coma or death.

“Vitamin A is important for eye health and infant development, but excessive intake during pregnancy can cause birth defects,” Hultin said.

Vitamin D toxicity, known as hypervitaminosis D, is also very rare but potentially dangerous. It is characterized by a buildup of calcium in the blood that can lead to nausea, vomiting, weakness, weight loss, irregular heartbeats, bone pain, organ damage and, in extreme cases, stupor and coma.

“Like any substance, too much of one thing has the potential to cause problems. The same goes for vitamins and minerals,” Hultin said. “I tell my clients the doses adapted to their age, sex and stage of life, not exceeding the recommended daily intake.

“In general, vitamins can be beneficial for your overall health and well-being. Be smart about the brands you choose, and don’t exceed the recommended amount on the label. If you have any questions about vitamins, speak to to your health care provider or registered dietitian nutritionist.”

Is there a health issue that worries you? Let us know via [email protected] We can seek advice from experts and your story could be published on Newsweek.


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