Symptoms of Vitamin Overdose in Children

Since you want your picky-eating toddler to get all the nutrition his growing body needs, you may consider giving him a daily multivitamin. But be cautious of the risk of your little one ingesting too much, which may cause a vitamin overdose with symptoms similar to those of food poisoning.

Children need to eat foods rich in essential vitamins and minerals in order to keep their bodies functioning properly. The American Academy of Pediatrics doesn't recommend multivitamins for healthy children who eat a varied diet. Although it's always best to get nutrients from foods, what should you do if your child isn't a vegetable-loving, cooperative eater?

Children who don't get enough vitamins and minerals from their diet, or who have certain medical conditions, might benefit from a single-nutrient or a multivitamin-mineral supplement. Although most multivitamins are safe if taken in the recommended dosage, they are drugs nonetheless, and overdose in small children is always a concern.

About 4.600 children are treated in emergency rooms every year due to accidental supplement overdose, according to the National Institutes of Health. This can happen from intake of both too many children's multivitamins or from overdose from eating adult supplements that children mistake for candy. Because children are not fully developed, they respond differently than do adults to certain vitamins, and toxicity can be serious.

Many children's vitamin-mineral supplements are sold as chewable tablets or gummies, a convenient form that your kids can take if they have trouble swallowing pills.

Over-the-counter supplements for children are generally safe when taken according to directions. However, if the supplements are not kept out of reach, children may be tempted by the sweet-flavored, colorful, chewable "treats" — and subsequently eat enough to result in vitamin poisoning, known as ‌hypervitaminosis‌. Initial mild symptoms of consuming too much vitamins can include:

• Nausea
• Rashes
• Headache
• Diarrhea
• Stomach cramps

Many minerals in supplements, whether formulated for children or adults, can be toxic in large amounts, but the most serious risk comes from iron or calcium.

Consuming adult iron pills is a leading cause of poisoning in young children, so it's important to make sure to keep iron-containing supplements and medications out of the reach of children.

According to the University of Chicago, most iron overdoses in children occur from accidental ingestion of ‌prenatal vitamins or multivitamins‌ containing ferrous sulfates. Because many of these adult-strength tablets are coated and colored, they appeal to kids.

The National Institutes of Health (NIH) has established a daily amount of iron needed to safely meet nutrient requirements for good health. If your child consumes more than these amounts, serious toxic symptoms could result. For children, recommendations are:

• Birth to 6 months: 0.27 milligrams
• Ages 7 to 12 months: 11 milligrams
• Ages 1 to 3 years: 7 milligrams
• Ages 4 to 8 years: 10 milligrams
• Ages 9 to 13 years: 8 milligrams

Tolerable Upper Intake Levels have also been set by the NIH. The amount for infants and children, from birth to 13 years, is 40 milligrams. This is the ‌maximum‌ amount of iron from foods and supplements based on the association of iron with gastrointestinal side effects.

Many common adult iron preparations contain as much as 65 milligrams of elemental iron, which is more than the recommended upper level for children, the NIH reports. Because of their small size, kids can quickly reach a toxic dose from swallowing adult or prenatal multivitamins.

Too much iron is corrosive to the tissues lining the gastrointestinal tract, such as the stomach and intestines. As a cellular toxin, iron can also damage cells that make up the tissues of organs such as the liver. Iron poisoning can cause symptoms such as:

• Nausea
• Vomiting
• Abdominal pain
• Diarrhea
• Bleeding

These symptoms may quickly cause excessive fluid and blood loss, which could result in seizures, coma, multiple organ failure and death.

If your toddler has eaten too many gummy vitamins made for children, there may a danger from a vitamin overdose, but it likely ‌won't‌ be from iron toxicity. Manufacturers of chewable children's vitamins do not generally add iron to gummy vitamins, perhaps due to the danger of iron overdose.

It's possible for your toddler to overdose on calcium from adult-strength dietary supplements or antacids. For example, Tums contain ‌calcium carbonate‌, which can cause toxicity in high amounts. Tums look like candy to kids, so the potential of getting sick from eating too many is a concern.

Average daily recommendations for the amount of calcium that children need depends on their age. According to the National Institutes of Health, the amounts for calcium are:

• Birth to 6 months: 200 milligrams
• Ages 7 to 12 months: 260 milligrams
• Ages 1 to 3 years: 700 milligrams
• Ages 4 to 8 years: 1,000 milligrams
• Ages 9 to 13 years: 1,300 milligrams

Any amount of calcium ingested above these recommendations may interfere with your child's ability to absorb iron and zinc. Other symptoms of a calcium overdose include:

• Abdominal pain
• Bone pain
• Coma
• Confusion
• Constipation
• Depression
• Diarrhea
• Headache
• Irregular heartbeat
• Loss of appetite
• Muscle twitching
• Nausea, vomiting
• Excessive thirst

Most water-soluble vitamins included in children's multivitamins do not generally pose a risk because excess amounts are excreted from the body with urine. Fat-soluble vitamins in supplements given over time have a greater potential to be damaging, because excess amounts are stored in the liver and fatty cells.

Too much vitamin D is especially harmful to infants and small children. The combination of fortified foods or formula plus vitamin D drops may account for higher than normal levels of vitamin D accumulating in the liver. Symptoms of vitamin D toxicity include:

• Excess calcium in the blood
• Nausea and vomiting
• Slowed mental and physical growth

Vitamin A is important to the health of your child's skin and eyes. However, excessive vitamin A intake from supplements and certain medicines can cause symptoms such as:

• Dizziness
• Nausea
• Headaches
• Vertigo
• Blurry vision
• Coma

Selenium is usually a component in multivitamins because children need it for proper thyroid function and protection against infection. Selenium toxicity can cause symptoms of:

• Hair and nail brittleness
• Hair loss
• Gastrointestinal disturbances
• Skin rashes
• Garlic breath odor
• Fatigue
• Irritability
• Neurologic disorders

Of the B vitamins, niacin may cause the most harm if ingested long-term by a small child. Niacin is often found in multivitamin supplements or B-complex vitamins. According to Linus Pauling Institute, too much niacin can result in symptoms of:

• Flushing — skin on the face, arms and chest turn red
• Severely itchy skin
• Skin rash
• Headaches
• Abdominal pain
• Nausea and vomiting
• Yellowing of the skin
• Blurred vision

If sudden symptoms occur in your child and you suspect she consumed something of concern, including more than one multivitamin, immediately contact poison control or call 911. Do not induce vomiting unless you are directed to do so. If you are advised to get your child to the emergency room, take the supplement container with you to the hospital.

Early medical treatment is important for recovery, especially with iron and calcium overdoses.