Most people probably associate tuberculosis with a leaky loft in 20th-century Paris. But as a matter of fact, tuberculosis is not ancient history.
It is estimated that two billion people globally suffer from the disease today. And each year, more than 1.5 million people die from it – mainly on the southern hemisphere in countries like South Africa, Namibia and Mozambique.
But vitamin D can help the immune system fight tuberculosis, a new study recently published in Frontiers in Immunology concludes.
“For the first time, we have shown that vitamin D improves the immune system’s ability to fight the tuberculosis bacterium, Mycobacterium tuberculosis,” says Associate Professor Martin Kongsbak-Wismann from the LEO Foundation Skin Immunology Research Center at the University of Copenhagen.
And we can thank a very special patient for making it possible for the researchers to prove the connection. She was born with a mutation that makes her body incapable of responding to vitamin D. The mutation is seen in very few people, and only around 200 occurrences of the mutation have been reported globally.
“We have compared cells from the female patient with cells from patients who are able to absorb vitamin D, and this revealed a difference between the two. It is easier for the immune cells of patients capable of absorbing vitamin D to fight tuberculosis. In the female patient, vitamin D does not do anything; her body simply does not respond to it,” says Martin Kongsbak-Wismann.
Today, tuberculosis is treated with antibiotics, but in the past many tuberculosis patients were admitted to sanatoriums and made to lie out in the sun. This caused their vitamin D levels to rise. Therefore, researchers have long suspected that vitamin D can help fight tuberculosis, but they did not have direct proof, until now.
What is tuberculosis? It is an infectious disease that mainly affects the lungs. People infected with the bacterium Mycobacterium tuberculosis (Mtb) risk developing tuberculosis. Like the corona virus, Mtb typically spreads through the airways. If a person suffering from active tuberculosis coughs, you may get infected if you inhale particles containing Mtb. The disease is mainly found in sub-Saharan Africa. In countries like Denmark, tuberculosis can be treated with antibiotics. But in countries where people do not have access to high-quality healthcare, the disease can be deadly. Globally, more than 1.5 million people die of the disease every year.
Good idea to give vitamin D to people exposed to infection
Martin Kongsbak-Wismann hopes the study can generate attention to the fact that vitamin D treatment is a useful tool for preventing and treating tuberculosis.
“It might be a good idea to give vitamin D to people highly exposed to infection with tuberculosis, e.g. the populations of specific African countries. Even though we still do not know how different levels of vitamin D affect the risk of infection and the severity of the disease, at least it would not cause any negative side effects,” he says.
However, you can still develop tuberculosis even though you take vitamin D supplements.
“You need to look at it this way: If you are exposed to infection, your immune system will try to fight the Mtb. And vitamin D will strengthen parts of the immune system. But if you have inhaled a lot of Mtb particles or other parts of your immune system do not function properly, you may still develop tuberculosis, even though your vitamin D level is normal. So it is not a ‘wonder drug’, but it is bound to help,” Martin Kongsbak-Wismann concludes.
How does vitamin D strengthen the immune system?
More specifically, the study showed that the female patient produced very few cathelicidins, which is a natural toxin found in the immune cells of the lungs needed to fight tuberculosis.
In most people infected by tuberculosis, tuberculosis bacteria attack the immune cells of the lungs.
The immune cells fight the bacteria by eating them. But the tuberculosis bacterium has developed various evasive mechanisms that reduce the immune cells’ ability to digest and thus to kill the Mtb.
“You could say that the tuberculosis bacterium has developed a way to lull the immune cells to sleep. This enables the disease the hide inside the immune cells, making it invisible to other parts of the immune system,” Martin Kongsbak-Wismann explains.
This is where vitamin D enters the picture. Because vitamin D is able to counteract the soporific effect of the tuberculosis bacteria by making the immune cells produce more of the cathelicidin toxin.
“Cathelicidin is like a microscopic needle that is able to pierce the tuberculosis bacteria. And when it does, it weakens the bacteria’s soporific effect on the immune cells. This restores the immune cells’ ability to kill tuberculosis bacteria,” says Martin Kongsbak-Wismann and adds:
“We were amazed by the effect of vitamin D. In immune cells from healthy control subjects, vitamin D improved the cells’ ability to fight Mtb, whereas in the female patient’s immune cells we saw no response to vitamin D. This shows that vitamin D is key to the immune system’s ability to fight Mtb and prevent tuberculosis.”
Can vitamin D supplements prevent tuberculosis? The short answer is no. Taking vitamin D supplements does not protect you from infection with tuberculosis. And this study does not say whether different levels of vitamin D affect infection and the severity of the disease.
The study does suggest, though, that vitamin D is a part to the immune system’s ability to fight Mtb. Therefore, the researchers behind the study recommend that we follow the Danish Health Authority’s recommendations regarding vitamin D to maintain normal vitamin D levels. The Danish Health Authority recommends a daily vitamin D supplement of 5-10 mg from October to April for adults and children aged five and up, because during this period, the body does not produce vitamin D this far north.
Frontiers in Immunology
Method of Research
Subject of Research
Reduced vitamin D-induced cathelicidin production and killing of Mycobacterium tuberculosis in macrophages from a patient with a non-functional vitamin D receptor: A case report
Article Publication Date
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.