The truth is that vitamin D deficiency is a major health problem in all age groups all over the world, even in countries where there is plenty of sunshine. (In the past, it was considered that a sunny climate offered enough protection against a deficiency.) But, not even food fortification programmes seem to completely prevent deficiencies. What’s more, many countries (including our own) simply don’t have any data and statistics on the problem.
Why is vitamin D important?
Vitamin D has various functions in the body for people of all ages. But for children it is especially important as it helps the body to absorb and retain calcium and phosphorus, nutrients that are crucial for building healthy bones. A shortage increases the risk of fractures in older children. A severe shortage can lead to a bone-softening disease called rickets, which can result in a child developing bow legs or knock knees, amongst other things.
How would you know if your baby has a shortage?
Most children won’t show symptoms of a deficiency, and the effects may only show years later. Some may experience bone and muscle pains. A shortage of vitamin D can lead to a calcium deficiency which can cause convulsions, especially in small babies.
Testing for a deficiency is not so easy. A blood test can be done to test vitamin D levels in the blood, but it doesn’t show the amount of vitamin D stored in body tissues. It is also not yet completely known what normal vitamin D levels should be, as not all people will develop symptoms of a shortage at the same blood level of Vitamin D. The current guidelines for when to supplement with vitamin D have been developed based on what would be the truth for most individuals.
The role of sunlight
When exposed to UV rays in sunshine the human skin has the amazing capability to manufacture its own vitamin D. Sunlight is the main source of vitamin D for humans, and most people will meet at least some of their vitamin D needs through exposure to sunlight.
The sun is less effective in winter. There will also be less exposure on a cloudy day and in partial shade. UV rays do not penetrate glass, so indoor exposure doesn’t help. People with fair skins are better able to manufacture vitamin D than those with a darker skin colour.
While suncreen blocks UV rays, it also reduces vitamin D production. But, as most people don’t apply enough sunscreen and don’t reapply frequently, some vitamin D production will still take place.
Getting 10-30 minutes of no-sunscreen exposure to sunlight over the middle of the day at least twice a week to the face, arms, legs or back should be enough for most people to maintain their vitamin D levels.
And as you can imagine, this creates a whole different dilemma. Due to the damage in our ozone layer, UV radiation is far more dangerous now than a few decades ago. Sun exposure is one of the biggest causes of skin cancer. For this reason, we can no longer advise no-sunscreen outdoor time.
What about vitamin D in food?
Very few foods naturally contain vitamin D. The best sources are oily fish (like salmon and mackerel) and fish liver oils, but these are not consumed frequently by most South Africans. Small amounts of vitamin D can, however, be found in beef liver, eggs and cheese.
Some foods are also fortified with nutrients to help provide for the needs of the majority of the population. Unfortunately, this vitamin D is not always well-absorbed into the body.
The controversy around supplementing
As for all other nutrients, a Recommended Daily Allowance (RDA) has been set for vitamin D by the Food and Nutrition Board. The RDA of a nutrient is the average amount needed in a day to fulfil the needs of nearly all healthy people.
In the case of vitamin D, the RDA has been set for people living in areas with minimal sun exposure. This makes sense as much of the research on this topic comes from countries where the sun shines a lot less than in South Africa. For many years it has been taught that supplementation in a country such as ours is unnecessary. Vitamin D deficiency has never been a big focus of healthcare in our country.
But lifestyle changes over the last few decades have changed this. Many people are indoors far more than outdoors. This includes children, who often spend significant amounts of time indoors in front of the television or on a phone or tablet. And because of the risk of skin cancer, you are also advised not not expose yourself (or your baby) to UV rays over the warmest time of the day without wearing sunscreen.
Vitamin D supplements
The American Academy of Paediatrics recommends a daily intake of 400 IU (international units) of vitamin D in babies, starting soon after birth and continuing throughout childhood.
It is true that breastmilk is low in vitamin D, even if mom is taking a vitamin D supplement. For this reason, all exclusive and partially breastfed babies should receive supplements. Don’t forget that breastmilk contains loads of other ingredients not included in formula milk, and most of these cannot be replaced with a supplement. Your breast milk remains by far the superior option for your baby.
If a baby is formula fed exclusively and drinks at least 1 litre of formula a day he should reach the 400IU needed as vitamin D is added into most formulas. Supplementation can start later on when he weans onto cow’s milk.
Vitamin D supplements can be found in a liquid form for babies and as chewable tablets for older children. Choose a supplement that contains vitamin D3 or activated vitamin D, otherwise it won’t be effective.
Christine Klynhans is a nursing sister and South African Certified Lactation Consultant (SACLC). She currently works at Parentwood Baby and Family Wellness Centre in Pretoria as a well-baby clinic sister and antenatal teacher. She also has a breastfeeding practice and a Breast Pump Demo Centre. She is passionate about supporting parents on the journey of pregnancy, breastfeeding and the early childhood years. Learn more about Christine Klynhans.