You’ve decided that your kid needs vitamins. Maybe you're worried about their nutrition because of picky eating. Or you’re trying to prevent them from bringing home the most recent round of the yuck from school or daycare. Regardless of why you give your kids vitamins, many parents wonder how long until vitamins work and hope for the answer to be “quickly!” of course!

How quickly vitamins work depends on many factors, from the type of vitamin to absorption rates. Let’s explore how long it takes vitamins to work, plus how to optimize your kid’s vitamin absorption with the right dose and smart food choices.  

How Are Vitamins Absorbed By Our Body?

Absorption is how the body changes a vitamin into the good stuff it can use. The digestive system is the key player in vitamin absorption for both adults and children. The gut absorbs vitamins, just like food. After passing through the stomach, the small intestine breaks down a vitamin supplement and the bloodstream absorbs it. 

Factors like solubility (whether the body’s fat or water carries and stores vitamins), the foods your child eats, and gut health impact how your kid’s body absorbs vitamins. 

Quality matters, too. Poor quality vitamins may not contain the right doses or pairings to maximize absorption–which may mean your child is getting too much or too little of the vitamins they need. 

Not all Vitamins Work the Same 

All vitamins are different, so it's tough to nail down a timeline that captures when they work. For example, your child’s body can use water-soluble vitamins, like Vitamin C, right away, especially if they take it with water. But your child’s body absorbs fat-soluble vitamins more slowly since the body carries and stores them differently.

A multivitamin is your best bet to ensure that your kid is receiving the nutrients they need every day. 

So, When Will You Start Seeing Results From Vitamins?

If you have a healthy child who eats a balanced, healthy diet, chances are they won’t feel any different once they start taking a multivitamin. But you can count on vitamins working at the cellular level even if your child says they feel the same. 

Kids who are low in certain nutrients because of picky eating, health conditions, or limited access to healthy foods may feel a big difference within a few days or weeks of taking a vitamin supplement. 

How long it takes for vitamins to work depends on the specific vitamin and how much they’re lacking. Basically, there isn’t a straightforward answer. A lot depends on each kid’s unique needs and circumstances. 

What Can Impact The Effects Of Supplements?

Lots of things impact how supplements, like a multivitamin, work inside the body. These factors include taking too much or too little of a vitamin, taking a vitamin with the right (or wrong) foods, and gut health. 

Dosage and deficiency levels

Make sure your kid takes a vitamin that meets their nutritional needs. For most healthy kids without worrisome eating habits, a children’s multivitamin fits the bill. Be sure to follow dosage instructions. There can be too much of a good thing–with nutrients, too much vitamins A and D and iron can be toxic.  

If you’re concerned about your child’s nutrition and think they may be deficient in a certain nutrient or vitamin, talk to their pediatrician. Your child’s pediatrician can check your child’s overall health and nutritional status and guide your next steps. This might include prescribing a specific dose of vitamins to replenish low levels. The time it takes for a vitamin to work depends on how deficient your kid is before taking it.

Absorption rate

Absorption rates of vitamins vary and depend on bioavailability. Put simply, bioavailability is the amount of the nutrient that your body digests, absorbs, and uses. Your kid’s age and overall health play a role in bioavailability and how long it takes for vitamins to absorb. 

Water vs fat-soluble vitamins

Fat-soluble and water-soluble vitamins work differently in your child’s body.  

Water-soluble vitamins such as B Vitamins and Vitamin C dissolve in water, which makes it easy for your child’s body to absorb and use. This also means they work faster than fat-soluble vitamins.

The small intestine absorbs fat-soluble vitamins, such as Vitamin A, D, E, and K.  There, they hitch a ride with proteins that carry them through the bloodstream before they’re stored in the body. This more complicated process means it takes longer for fat-soluble vitamins to work, compared to their water-soluble friends. 

Nutritional pairing

Vitamins are interconnected. And how long it takes for vitamin supplements to work depends on these connections. 

For example, Vitamin D increases calcium absorption. So if your kid is low on Vitamin D, chances are they aren’t absorbing calcium quickly or effectively. Try enhancing calcium absorption by having your child drink a glass of milk alongside their Vitamin D supplement.

Diet

Supplements aren’t meant to replace a healthy diet. Rather, vitamin supplements and good nutrition go hand in hand. The right foods set the stage for vitamins to work. And certain vitamins and foods make excellent partners.

For example, Vitamin C improves iron absorption. So have your kid eat an orange with their iron supplement, or find an iron supplement that is already paired with vitamin C.

Talk to a pediatric dietitian nutritionist to learn more about jumpstarting vitamins with smart food choices. 

Health problems

Health issues may slow down vitamin absorption. So it may take longer for vitamins to work if your kid has a health condition, especially one that affects the gut–where nutrients get absorbed. 

If your kid has any medical conditions, be sure to talk to their pediatrician about special diets or vitamin supplements they may need to close the nutrient gap.

Which Kids Need Vitamin Supplements?

Let’s face it. Parents are busy and can’t always prepare a well-balanced, home-cooked meal. And that’s ok! 

Giving your child a daily multivitamin can help you feel confident about your child’s health, especially on days when their intake is less than ideal… I’m talking about those chicken nuggets/mac and cheese/frozen pizza days when your parental sanity (perhaps survival!) depends on it. We’ve all been there!

Pediatricians may recommend a daily multivitamin or mineral supplement, especially for:

• Kids who aren't eating regular, well-balanced meals made from fresh, whole foods

• Finicky eaters who simply aren't eating enough

• Kids with chronic medical conditions (be sure to talk with your child's doctor before starting a supplement if your child is on medication)

• Kids eating a lot of fast food, convenience food, and processed food

• Kids on a vegetarian or a vegan diet (they may need an iron supplement), a dairy-free diet (they may need a calcium supplement), or other restricted diet

• Kids who drink a lot of carbonated sodas, which can leach, or pull out, vitamins and minerals from their bodies

What Is the Best Time of Day To Take Vitamins for Maximum Effect?

Since so many factors impact how well and how long it takes vitamins to work, you’re probably trying to figure out the best time of day to give your child their vitamin.

In general, it's best to give your child their multivitamin with a meal and a glass of water. An expertly formulated multivitamin will account for any absorption conflicts. Most experts recommend taking the supplement during breakfast, allowing your little one’s body to absorb and use the nutrients throughout the day.

Now that you know the ins and outs of how long it takes multivitamins to start working (refresher: there’s no easy answer!), I hope you feel more equipped to make the right choice for your family.