It’s Healthy Back to School Week.  All week I will be breaking down ways to keep your family healthy as you head back to school. Along the way, let’s bust some urban myths — and likely save you some money!

There is no end to vitamins being marketed in shops and online that make claims to boost immunity or keep you healthy. We’ve talked alot on this blog about unnecessary supplements. Let’s focus on two of the most common:  Vitamin C and D.  What should a smart parent or savvy shopper know?

Vitamin C

Okay, exactly what is it and why do we need it?  Adequate Vitamin C is essential for a healthy immune system, as well as other aspects of health.  (Ever read about scurvy?  The disease was famous for affecting 18th century sailors who developed bleeding gums, loose teeth, and easy bruising after weeks at sea without fresh fruits or vegetables.)  In modern times, scurvy is rare – and for good reason:  Vitamin C is easily absorbed in a healthy diet.

So, if deficiency isn’t that common, why is everyone selling it to me?   It actually comes down to a man named Linus Pauling.  Pauling was a brilliant man and a Nobel Prize Laureate.   While he was a brilliant chemist, he was duped by someone (who happened to have patents on Vitamin C preparations)  into believing that Vitamin C was, literally, the elixir of life.   At the end of his life, he was taking up to 18,000mg a year and published a book called Vitamin C and the Common Cold. It’s worth noting that although he was an accomplished scientist, he forgot the first rule of science and that is evidence. Despite no evidence – and criticism from medical doctors – he continued to promote Vitamin C as a cure for everything, even AIDS.   He never did any studies nor had he any evidence to back up his ideas or claims.  In fact, 20+ studies done since the 1970’s on Vitamin C, “immune boosting”, and the common cold have shown it has no effect.  The myth is so persistent, that during Covid in 2020, there were even trials to treat critical Covid patients with extra Vitamin C (spoiler:  didn’t work).

If you are worried about getting enough Vitamin C, the easiest way to get it is by increasing fruit and vegetable intake.  Frozen fruits and vegetables are equally good. In fact, your body absorbs vitamins better from real food than it does from prepared supplements.

So, what happens if you take Vitamin C you don’t need?  Mostly, it just becomes expensive pee.  At very high excessive doses, it causes flatulence and diarrhoea.

TL:DR: Adequate Vitamin C is found in the diet, and is important for health but extra won’t do anything, and certainly doesn’t “boost your immune system” or treat the common cold.

Vitamin D 

Adequate Vitamin D is essential not just for a healthy immune system, but also for bone health!  Unlike Vitamin C, deficiencies are more common because Vitamin D is the “sunshine vitamin” — there’s often not enough in our diets – even with oily fish and eggs and fortified foods (like milk that has had Vitamin D added).   So, how much do you need? 

• Infants under age 12 months need 5µg Vitamin D per day (even if they are breastfed or you took Vitamin D during pregnancy!).  The exception is infants who are taking more than 300mL per day of fortified formula. Read more

• Children aged 1-4 need 5µg per day.  This should be between Halloween and St. Patrick’s Day.  For this age group, choose a liquid or drop since tablets and chewables are choking risks.

• For healthy children (aged 5–11 years) with fair skin who get sunlight exposure during summer:  a daily vitamin D supplement containing 10 µg (400 international units (IU)) should be taken between end of October to March.  However, for those of darker-skinned ethnicity a daily vitamin D supplement containing 10 µg (400 IU) taken throughout the full year is expected to meet their requirements.

•  For healthy teenagers and adults (aged 12–65 years) with fair skin who get sunlight exposure during summer: a daily vitamin D supplement containing 15 µg (600 IU) should be taken from end of October to March).

• For those of darker-skinned ethnicity and for individuals of all ethnic groups who are pregnant, a daily vitamin D supplement containing 15 µg (600 IU) taken throughout the year.

• Always forgetting to take the Vitamin D?

  If you are always forgetting to give those infant drops or take the Vitamin D, make it part of your daily routine. Try this: Keep the Vitamin supplement in a kitchen cupboard, but out of reach of little hands. Set a phone, Alexa or other digital reminder to remind you to take them/give them at breakfast time/morning feed or bottle for infants every day. For children over 4, a tasty gummy vitamin is an incentive for them to start reminding you after a few days.

What else to know about Vitamin D?

• Vitamin D supplement of 10 µg for children and 15 µg for teenagers and adults in Ireland is considered safe.

• Excess Vitamin D beyond this amount is unnecessary and does not “boost the immune system”

• Read the label or ask your registered pharmacist for help selecting a supplement.  Not all multivitamin preparations have adequate Vitamin D! Many multivitamins have lots of stuff you really don’t need – but not enough of what you really do need!

• Unlike with Vitamin C (your body just gets rid of the excess) you can get too much Vitamin D!  Excess levels don’t boost your immune system which can cause changes to your body’s calcium levels and cause health problems!  While serious problems are rare, doses higher than 2000 µg can cause problems.  There is no reason to take more than 800µg/day, and doses over 1000µg (unless prescribed by an IMC registered doctor) should be avoided.

• Read More:  Current Update Recommendations on Vitamin D

If you are concerned that your child has a vitamin deficiency or has a health condition, start by talking to your PHN, GP or  a dietitian with INDI and CORU registration (the recognised qualifications to give dietary or nutritional advice to children in Ireland). Note:  not all “nutritionists” are dietitians, and always check professional qualifications before seeking advice on your child’s diet.