Why vitamin D is vital for your immune system

Vitamin D plays a critical role in your bone health and a deficiency can affect your immune system. A Mediclinic expert explains what you can do to boost your calcium levels and stay healthy this winter.

Vitamin D and bone health: what’s the connection?

Vitamin D is a fat-soluble vitamin also known as calciferol. It plays an essential part in your health, being crucial for bone strength and a good immune system. Patients with vitamin D deficiency may suffer from headaches, fatigue, depressive mood, hair loss, and recurrent infections. “The role of vitamin D in immunity is complex and wonderful. Although it is still being researched, studies have shown that vitamin D can modulate your immune responses by controlling the growth and differentiation of different immune cells, such as T-cells, B-cells, and macrophages [a type of white blood cell],” says Dr Loube de Ridder, a GP at Mediclinic Bloemfontein.

Natural and synthetic sources of vitamin D

Natural sources of vitamin D can be found in certain foods – among them fatty fish, fish oils, eggs, cheese and liver. Dr De Ridder adds that safe sun exposure is also crucial for your body to synthesise vitamin D. This process starts in the skin under the influence of UVB exposure. It’s recommended that you get 5-30 minutes of sun exposure daily. 

Synthetic sources of vitamin D are also widely available, but your doctor must first determine whether you need treatment for a confirmed deficiency or if taking a supplement is a supportive measure. “The US Food and Drug Administration (FDA) says a person needs 20mcg/800IU of vitamin D daily. If for any reason you can’t meet this criterion, it’s advisable to use a daily supplement you can buy off the shelf at a pharmacy. If a patient has a confirmed vitamin D deficiency, their healthcare professional will prescribe vitamin D at the recommended dosage – usually 50 000 IU per week,” says Dr De Ridder.

Seasonal physiological changes

“Your body undergoes changes in winter because you must expend more energy to maintain a normal body temperature. Lower temperatures might make people more susceptible to infections, but the human body is very adaptable, and we can flourish in various climates,” Dr De Ridder says. “What happens outside of the body in winter might be of more importance, and this is an excellent opportunity to bust the myth that cold temperatures cause disease.”

In winter months, you spend more time indoors – sometimes with poor ventilation, which makes the spread of viruses more likely. A virus also becomes more stable in colder temperatures, causing it to stay viable for longer and increasing the prevalence of infections. Even when it’s cold, it’s important to keep exercising outdoors. You get your recommended sun exposure, and it helps with stress management.

Dr De Ridder says it’s vital to maintain a good foundation with a healthy, balanced diet to prevent you from becoming prone to bacterial or viral infections. “We’ve generally been brainwashed over time to focus on dietary restrictions to be at our goal weight. Instead, you should focus on what you can add to improve your health. It’s much more beneficial to focus on a nutrient-dense diet that contains all your vital vitamins and minerals,” she explains.

Another key thing you can do to stay healthy is to have your annual flu vaccine. It decreases the prevalence and severity of influenza infections dramatically and is widely available. The vaccine is safe from six months of age and is particularly recommended for people who are immune compromised. 

To find a GP near you, go to www.mediclinic.co.za.