When asked what the most important vitamin to promote a healthy immune system is, most people will automatically say vitamin C. Praised for decades for its ability to help fight colds and flus, develop and repair tissue, heal wounds and maintain healthy bones, cartilage and teeth, this powerhouse vitamin takes centre stage in every supplement aisle. If you were told you could take only one supplement for the rest of your life, we can almost guarantee that the majority of people would choose vitamin C. For decades, we have relied on it almost solely to improve our health.
That was until February 2017, when scientists at the University of Queen Mary in London discovered that vitamin D, which was previously thought to have bone and muscle health benefits only, has the ability to protect the body against acute respiratory infections including colds and flus. Health experts across the globe took note, and before long, vitamin D took centre stage in the fight against colds and flus.
Also known as the “sunshine vitamin,” vitamin D is believed to protect the body from respiratory infections by boosting the levels of antimicrobial peptides in the lungs. These peptides are antibiotic-like substances that occur naturally in the body and protect the lungs from infection. This explains why vitamin D has shown an ability to reduce asthma attacks (especially for those whose asthma symptoms are exasperated when they are sick with a cold or flu).
Before these discoveries were made, experts already knew that this vitamin had a lot to offer, most notably when it comes to bones and teeth. Vitamin D works with calcium and phosphorus to build and maintain strong bones. It is also involved in nerve transmission, neuromuscular and immune function, and is a powerful antioxidant. In essence, vitamin D plays a critical role in both immunity and bone strength; getting too little can increase your risk of infections and limit bone development.
This fat-soluble vitamin is present in very few foods. As a result, it is often added to foods like milk, yoghurt, orange juice and margarine, and is widely available in supplement form. Other than oily fish (such as salmon, tuna, and mackerel) and fortified dairy and dairy alternatives, not many foods are high in vitamin D. Small traces are found in egg yolks, liver and cheese, but even if you regularly consume these foods, it is likely that they will not offer enough vitamin D to satisfy the body’s needs. This is why most of our vitamin D intake will come from sun exposure or supplementation.
So how does spending time outdoors increase the body’s vitamin D levels? When sunlight hits our skin, it makes vitamin D from cholesterol. Sound too good to be true? The sun’s UVB rays hit the cholesterol in the skin cells which produces energy for vitamin D synthesis to occur. This means that your body can literally get enough vitamin D simply by spending a little bit of time in the sun every day. Despite exposure to the sun being good for you in terms of getting vitamin D, we also know that it’s dangerous for the skin, making some people hesitant to do it. So how much vitamin D do we actually need?
Your vitamin D Recommended Daily Amount varies by age:
- Infants 0 – 12 months require 400IU (10 micrograms)
- Children and adults require 600IU (15 micrograms)
- Adults 71 years and older require 800IU (20 micrograms)
Vitamin D supplementation is often necessary because it is difficult to meet the requirements from food alone and because sun exposure is not always possible or recommended. In many Northern countries where sunny days are few and far between, it is almost impossible to get the required daily amount of vitamin D from sunshine alone. On the other end of the spectrum, people are also spending less time in the sun to avoid the harmful effects of the sun’s rays on the skin. Between not being able to access sunshine, and not wanting to spend too much time in the sun, the majority of us are not getting enough vitamin D from the sun alone.
In fact, the American Academy of Paediatrics recommends supplementation for many babies and children, not just for adults (see below). This is particularly important for breastfed infants as breastmilk does not, surprisingly, contain enough vitamin D to meet baby’s needs.
How do you know if you should be taking a supplement?
Supplementation is often recommended for the following groups of people who are particularly prone to deficiency:
- Breastfed infants and combination fed infants, because breast milk is not a good source of vitamin D.
- Formula fed infants drinking less than 945ml of vitamin D fortified formula per day.
- Children drinking less than 945ml of vitamin D fortified milk.
- Adolescents who do not get 600 IU (15 micrograms) of vitamin D per day in their diet.
- People with a darker skin tone. Dark skin produces less vitamin D from the sun. Melanin (the pigment that gives skin its colour) lowers the skin’s ability to make vitamin D in response to sunlight. Therefore the more melanin (pigment) in the skin, the less vitamin D it can produce.
- People with fat malabsorptive conditions, such as Crohn’s disease, celiac disease or cystic fibrosis. Vitamin D requires fat for proper absorption, so if the body cannot absorb fats from its diet, it won’t absorb vitamin D.
- Those with limited access to sun exposure, including people who live in northern regions of the world. This may also include people who have access to sunshine, but choose to spend most of their time indoors, or those who work night shifts.
- People who do not consume vitamin D fortified products, such as dairy, due to allergies, intolerance or dietary choice.
- People who follow a vegan diet, as vitamin D is naturally found in animal products and manually added to dairy products.
How to ensure your family is getting enough vitamin D
To ensure your baby or child is getting enough vitamin D, reference the above guidelines and talk to your physician about what is right for your child. Every adult, child and baby’s body has its own unique needs, and while we can follow general guidelines, health advice is not one-size-fits-all.
The American Academy of Paediatrics recommends that breastfed infants, and combination fed (breast milk and formula) infants should be supplemented with 400 IU of vitamin D per day beginning soon after birth.
Formula fed infants and older children (who drink less than 945ml of vitamin D fortified infant formula or milk per day) should be supplemented with 400 IU of vitamin D per day.
Breastfed and bottle fed infants should be given a vitamin D supplement in liquid form. To determine exactly how much your baby needs, talk to your healthcare provider at your baby’s next check-up appointment.
Adolescents who do not get 600 IU in their diet should be supplemented with 600 IU per day.
Most parents will not know whether or not their baby or child is getting enough vitamin D for their age, so it’s best to discuss this with a trusted healthcare professional.
Include food sources that contain vitamin D in your baby or toddler’s diet.You can find naturally occurring vitamin D in oily fish (trout, salmon and sardines), egg yolks, and shitake mushrooms. Many other foods are fortified with vitamin D during processing, including some yoghurt, cow’s milk, and dairy alternatives such as soy, almond, and rice milks, and even orange juice. Check the labels on your milk and milk alternatives, orange juice, yoghurt and cereals for information on added vitamin D. If vitamin D has been added, it will be stated on the label. Take note that fruit juice is not recommended for babies under 1 year of age, and only 118ml total per day is recommended for toddlers. Babies under 1 year of age should also not drink cow’s milk.
How would you know if you have a vitamin D deficiency?
If you or your children spend most of your time indoors, do not consume much fish or dairy or always wear sunscreen when going outside, you may be at risk of developing a vitamin D deficiency. The symptoms of this deficiency are subtle and are not exclusive to having a lack of vitamin D. This makes it very difficult to self-diagnose, and the only way to know for certain is to have your vitamin D levels tested by a doctor. Signs to look out for include:
Getting sick with colds, flus, bronchitis or pneumonia often.
Chronic fatigue or feeling tired for no particular reason.
Pain in your muscles, bones or lower back.
Depression and seasonal depression.
Slow or impaired healing of wounds.
As you can see from the list above, there are no definitive symptoms to look out for. However, if you experience any of these common signs, it would be good to mention it to your doctor, who will likely run some tests to find out if they are a sign of a vitamin D deficiency, or perhaps of another health condition.
Because vitamin D is essential for the development of healthy bones and teeth, a lack of vitamin D is particularly dangerous for children. Very low vitamin D levels can lead to soft bones, causing rickets. Rickets occur when children are growing. If a child has soft bones, the bones can bend while growing, which results in knock knees or bow legs. A vitamin D deficiency in childhood is also linked to brittle bones and frequent fractures, and osteoporosis in later life. That is why it is essential to nip a deficiency in the bud before it causes long-term health problems.
Children also need vitamin D for the formation of strong and healthy teeth. This is particularly important in the early years when the body starts to produce milk teeth / baby teeth, and prepare its permanent teeth / adult teeth. These begin to develop in the jaw at birth and continue to develop after the child is born.
The good news is that once a vitamin D deficiency is detected, it is usually easy to correct with good quality supplements, and when treated early enough, it will not lead to long-term health problems.
Is there such a thing as too much vitamin D?
You cannot overdose on vitamin D that you get naturally from spending time in the sun. You can, however, suffer burns and more serious skin damage from spending a lot of time outside, so be sure to protect yourself from the sun’s UV rays. This means wearing a hat, sunglasses and SPF, and avoid extended time outdoors during peak hours (between 11am and 2pm).
Taking too much vitamin C in the form of supplements, over a prolonged period of time, may lead to a build-up of calcium in the body. This is known as hypercalcaemia, which can weaken the bones and damage the kidneys and the heart. If you or your child have a medical condition, do not take vitamin D supplements without consulting your doctor first.
Although vitamin D is one of the most important vitamins the body needs, it is often overlooked in the supplement aisle. While most parents are diligent about ensuring their child eats enough fresh fruit and vegetables, and gets enough calcium, vitamin D is sometimes overlooked, simply because it is not as well-known as other vitamins. Ensuring your child gets enough vitamin D will help protect them from colds and flus, build strong bones and healthy teeth and help limit the effects of asthma. If you are worried about your or your children’s vitamin D intake, talk to your GP or healthcare practitioner about supplementation. They will be able to determine whether or not supplements are necessary, and if so, how much you should be taking to suit your body’s unique needs.