Vitamin C & D3 for Kids - Ask a Nutritionist

November 2, 2023

Vitamins are a great way to boost immunity, not only for kids but for everyone. As the weather gets colder and exposure to germs and bugs get higher it's important to keep our immune systems strong. Tune into this week's Ask a Nutritionist with Teresa to learn all about vitamins and more for immune health.

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Welcome to the “Ask a Nutritionist” podcast, brought to you by Nutritional Weight and Wellness. We are thrilled to have you join us today as we discuss the connection between what you eat and how you feel, and share practical real life solutions for healthier living through balanced nutrition. Now let's get started.

TERESA: Welcome to Dishing Up Nutrition's midweek segment called “Ask a Nutritionist”. I am Teresa Wagner, a Registered and Licensed Dietitian. On today's show, brought to you by Nutritional Weight and Wellness. I will be answering questions that we have received from one of our Dishing Up Nutrition listeners.

Today's question is, “How much vitamin C and vitamin D3 can I give my kids? They're four and seven years old; to help boost their immunity during cold and flu season?” So I think this is a great question. At this time of year, I think many of us are looking for ways to boost our immune system, and we as parents are especially concerned about our children, whether they are in daycare or in school where exposure is higher. Because we as parents know that when our kids get sick, not only do they not feel well and we don't want that for them, but they also are likely to miss school. And if they're a missing school, we ourselves are more likely to get sick and may have to miss work, or it just makes taking care of our families just all the more difficult.

So let's start this question with answering the question about supplementation and then move on to low cost or no cost ideas to help improve the health of our children's immune system. And you don't need to be a child or have children for these tips. They are beneficial for anyone looking to boost their immune system.

Vitamin C dosing recommendations

Let's start with vitamin C supplementation. The RDA or the recommended daily allowances for four to eight year olds, which would cover the two children she was talking about, is 25 milligrams per day. For nine to 13 year olds, it's 45, and for 14 to 18 year olds it's 75 milligrams. When we're talking about the RDA though, the recommended daily allowances that are set up by the governing bodies, we need to understand that these levels are set at the lowest dose to prevent disease.

In the case of vitamin C, the disease of concern is scurvy. This is not the optimal level of vitamin C for your children or the nutrients that the RDA has set for. These are not the optimal levels. These are just the bare minimum. So when you look at supplements for children and it says it's over 100% of the RDA, it's no wonder we as parents get a little nervous that we might be poisoning our kids with vitamins.

But when we know the why's behind the RDA, it's not so scary anymore. With younger children, you can supplement with ranges between 200 to 350 milligrams of vitamin C, as are the levels in the multivitamins that we offer for kids on our Nutrikey website. Depending on the age of the child, this will be anywhere from close to 400% to almost 2000% of the RDA. Like I said, those percentages can sound kind of scary if you don't know what those levels are based on.

And certainly if you are uncomfortable, you are welcome to use half doses if you're not comfortable with those levels. As the body weight of the child goes up, so does the amount of the nutrients required. So we can adjust recommendations based off of weight rather than age, just like your pediatrician does dosing for medications based on weight, not age. If your child is a peanut, then look at the lower amount on the supplement recommendation. And if they're getting closer to an adult body weight, then we adjust up.

Vitamin D dosing guidelines for children

Speaking of dosing off of weight and not age, when trying to figure out the proper amount of vitamin D for children, that's exactly how we do it. For vitamin D, we recommend 1000 IUs per 25 pounds body weight. So if your child is 50 pounds, that would be 2,000 IUs. Once your child hits 125 pounds, a weight that would be considered an adult body weight, they would be at the recommended adult vitamin D amount that we often give for adults, which is 5,000 IUs per day. The RDA for vitamin D is set at a level to prevent rickets in children. It is not set at the optimal dose for immune function in children.

Other immune supportive supplement considerations

Another couple of ideas to think about for supplements for children is cod liver oil and probiotics. Cod liver oil can be a great option. One teaspoon for young children provides omega’s and some vitamin A, which are both great for immune health. Most of our kids are not getting enough omega-3’s from their foods, 'cause many kids don't like to eat fish, which is one of the best sources of omega-3’s. There is a small amount of vitamin D in cod liver oil, but I would still recommend taking additional vitamin D if you choose to go with cod liver oil.

As far as probiotics, they may be something you want to consider, especially if your children have ever been on an antibiotic. A quarter of a teaspoon of our Bifido Powder taken one to two times per day, just mix it with water or you can put it in foods they would dissolve easily in like maybe yogurt or applesauce. An unsweetened applesauce would be a way that you could give that probiotic to your children.

For specific supplements, I invite you to check out the children's tab on the Nutikey website. It's There are links to three different children's multivitamins, the probiotic powder I recommend and the cod liver oil. Vitamin D is not on the children's page, but it is on the website so you can just search for vitamin D. And the form that I find easiest to give to children is the liquid form vitamin D 1,000. Just one drop provides a thousand IU’s. So it's very easy to titrate for your child based on their weight.

How to eat to promote a strong immune system

So now let's talk about some general lifestyle practices to promote a strong immune system. I'll focus on addressing this for youth, but all these ideas pertain to adults as well. So let's start with the nutrition piece. After all, the show is Dishing Up Nutrition. To support the immune system, it is important to have a solid food foundation. That foundation is built from proteins, fats, and carbohydrates.

Of course not all proteins, fats and carbohydrates are created equal. What I'm talking about are real food nutrients; proteins from animal sources such as beef, chicken, turkey, fish, seafood, dairy products, carbohydrates from mostly fruit and vegetable sources and healthy fats that are derived from naturally fatty sources. Think olives and olive oil, avocados, avocado oil, coconut and coconut oil, butter, raw or dry roasted nuts and seeds. Nature made these foods fatty, not a refining process from a food manufacturing plant like seed oils or converting carbohydrate based foods into a fat like vegetable oil, corn oil, soybean oil or canola oil.

These macronutrients: proteins, fats and carbs support immune health in different but important ways. Proteins are made of amino acids. These amino acids turn key players on in your immune system: T cells, B cells and antibodies. They turn them into germ fighters that spot and kill pathogens that enter your body before they can start an infection. Carbohydrates such as vegetables, beans, legumes, and fruits are high in vitamins like the vitamin C that we talked about. They're high in minerals and antioxidants, which are key to a healthy immune system. They also contain fiber. And fiber is the food for the bacteria in our microbiome. It's thought that 70 or more percent of our immune system is housed in our gut. So supporting the good bacteria of the microbiome is important.

Healthy fats are an energy source for the immune cells and provide the structure for the cells, immune cells included. They make up the membrane that encapsulates the cell. This membrane influences the behavior of the proteins involved in the immune function and activation. That fatty membrane works like a gatekeeper helping to control what gets in and goes out of the cells.

So as you can see, each macronutrient is important for immune health and should be included as a part of an immune supporting food plan. As you're looking at what you and your children are eating, evaluate if you're getting the basic nutrients your body needs to support the immune system. Are they, are you eating a protein, a vegetable, a fruit, and healthy fats at meals? What about at snacks?

Sugar dampens the immune system

In mentioning snacks, I would be remiss if I didn't mention sugar: sugar from juice, soda or any sweetened beverage, sugar from candy baked goods or any other food that's high in sugar dampens the immune system. It lowers the ability to fight off viruses and infections, having spikes in blood sugars, which unfortunately happens all too often in children and adults because of how we've been accustomed to eating. What we are accustomed to doesn't seem like it might have that much sugar.

But yes, that 16 to 20 ounce bottle of soda is enough to dampen your immune system and that dampening is thought to last about five hours. For some, this can be happening all day based off of the foods and beverages that we are choosing to eat and drink. For kids, maybe it's not soda, but maybe it's juice. Juice has just as much sugar ounce per ounce as soda does. So keep in mind that kids based on height and weight cannot handle the same amount of sugar as an adult. So having soda or juice while not healthy for an adult is even worse for a child.

Sleep supports immunity

Other lifestyle factors to consider for robust immune health: sleep. Toddlers and preschool aged children need between 10 and 14 hours, and this includes time spent sleeping during naps. Six to 12 year olds need nine to 12 hours. Teens need eight to 10 hours. Sleep plays a critical role in immune health, and one of the best things we can do to support our children's immune system is to structure our lives to allow them to get the sleep that they need. This includes removing all screens from bedrooms.

Exercise supports immune function

Another lifestyle factor to consider is exercise. Kids do not need structured workouts, but they should be active for at least an hour every single day, preferably outdoors. This helps on multiple fronts. Being physically active in and of itself supports immune function. Getting outside in the fresh air is important because one of the reasons we get sick in the winter is because we are spending more time indoors breathing the air that everybody else is breathing. So getting outdoors and getting some fresh air is important for immune health.

And another front that this is helpful on is if kids are outdoors, they're more likely to get dirty. Getting dirty supports the immune system. The dirt outside is full of friendly microorganisms that can train the immune system and build a resilient immune system. Overuse of hand sanitizers, antibacterial soaps, and chlorine-based cleaners, while can be appropriate in certain circumstances, should not be our daily regular mode of cleaning. Plain soap and water is much better for the immune system. In talking about exposure to bacteria, it is interesting to know that kids with pets or kids who live on farms or have some sort of regular exposure to animals have a more diverse microbiome, which we know is immune system supportive.

The importance of staying properly hydrated

Lastly, just like adults, kids need to stay properly hydrated. When we are dehydrated, we are susceptible to germs. And for kids like adults, we can use that half their body weight in ounces of water for proper hydration. So if your child weighs 75 pounds, 35 ounces of water would be the appropriate amount for that child.

Well, that's it for now. Thank you so much for listening to Dishing Up Nutrition’s “Ask a Nutritionist”. If you have a nutrition question that you would like us to answer, join us on our private Dishing Up Nutrition Facebook page and leave your questions there. We look forward to hearing from you.

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