A group of researchers conducted a statistical analysis of one aspect in the global study of the coronavirus disease. Their analysis focused on the strong correlation between vitamin D and COVID-19 mortality. They found that vitamin D might explain why the mortality rate is higher in adults than in children.
The researchers who made further investigation into the link between vitamin D and COVID-19 mortality were from Northwestern University, a private research university in the US. Their findings suggested that the role of vitamin D in immune regulation resulted in the immune-related complications of some patients. The same role might also explain why the mortality rate among children has been low. They published the results on the website medRxiv.
Vitamin D and Sunshine
Due to poor evolutionary design, the human body is flawed in extracting calcium from food sources. At a young age, particularly during infancy, the body can extract as much as 60% of calcium from food. However, that rate begins to shrink as the person grows older. This is one reason why older adults are prone to osteoporosis if their calcium intake was low when they were younger. The maximum absorption rate of calcium in adulthood is about 20% from food sources.
Fortunately, there is a chemical that can increase that absorption rate: vitamin D. In truth, vitamin D is a hormone the skin can produce with the help of sunshine. In many cultures, people are advised to get some morning light for several minutes to let their body get vitamin D. Once the skin is exposed to sunshine, it can produce different variations of vitamin D usable for physiological processes. Any excess will be stored in fat cells.
According to WebMD, an American health website, people who wake up early in the morning can get vitamin D at the most optimal condition. This is because sunshine in the early morning does not hurt the skin. They simply have to spend about 5 to 15 minutes under the sun to let the skin produce vitamin D. Though, people with a dark complexion may have to spend up to 30 minutes under the sun. If done regularly, the body will have enough supply of vitamin D, which can be utilized to improve the extraction of calcium.
The habitual exposure to sunshine in the early hours of the morning can go a long way in terms of health benefits. First, the abundance of vitamin D allows the body to extract more calcium from food sources. Second, the abundance of the hormone prevents the body from borrowing calcium stored in bones. This helps prevent bones from becoming brittle. And third, the abundance of the hormone can assist the immune system in regulating many of its functions, including inflammation.
Vitamin D and COVID-19
At Northwestern University, researchers were inspired by the growing evidence of a link between vitamin D and COVID-19. They examined the data from several countries and discovered that the link exists in some death cases. However, they warned people that even with a strong association, there is no need to stockpile vitamin D supplements, especially if they do not have a deficiency. The mysterious link would be best applicable in medical settings, wherein patients with low vitamin D levels might require supplementation to help fight COVID-19.
"While I think it is important for people to know that vitamin D deficiency might play a role in mortality, we don't need to push vitamin D on everybody. This needs further study, and I hope our work will stimulate interest in this area. The data also may illuminate the mechanism of mortality, which, if proven, could lead to new therapeutic targets," explained Vadim Backman, lead author of the study and professor of biomedical engineering at Northwestern.
The deeper investigation in the correlation was triggered by the lack of explanation from other factors. Some entities hypothesized that the link might be explained by age distributions, testing rates, strains of the novel coronavirus, and even the quality of patient care. But none of those factors convinced the researchers. So, they studied publicly available data in different parts of the globe, which included data from Germany, South Korea, China, Switzerland, Iran, France, Spain, Italy, the US, and the UK.
The most prominent association was between vitamin D and cytokine storm, an inflammatory overreaction of the immune system. They also noted the connection between vitamin D and mortality rates. Because the hormone was in the middle of two outcomes of COVID-19, researchers said that the chemical's position might be where its critical role played out.
As one of the regulators of the immune system, vitamin D can boost the innate immune response to avoid escalating an infection. By preventing an unnecessary escalation, vitamin D will hold off the adaptive immune response for an extended period. This should reduce the odds of an overreacting immune system. This may explain the link to the cytokine storm.
For the link to mortality rates, the low levels of vitamin D may explain both adult and pediatric death cases. Adults, particularly healthy ones, tend to have a stronger immune system compared to older adults, adults with chronic diseases, older children, and infants. But their tough immune system may react wildly to a novel pathogen that has spread to multiple areas. That toughness can kill both the pathogen and the body.
On the other hand, pediatric death cases from COVID-19 remain low across all countries with infection cases. With a premature immune system, pediatric cases rarely report immune-related complications among healthy kids who got infected by the virus. That prematurity prevented their immune system from unleashing massive amounts of inflammatory chemicals into the body. As such, children with COVID-19 will likely suffer from different complications, such as secondary bacterial infection and respiratory failure.
According to the World Health Organization, a specialized agency of the United Nation, Europe remains severely affected by the COVID-19 pandemic. As of May 7, 2020, a total of 1,626,037 cases and 150,238 deaths were reported by affected nations. Within 24 hours, 32,209 new confirmed cases and 2,458 new deaths were verified by these countries. The five European nations with the highest cases were Spain at 220,325, Italy at 214,457, the UK at 201,205, Russia at 177,160, and Germany at 166,091. For death cases, the top five countries were the UK at 30,076, Italy at 29,684, Spain at 25,857, France at 25,769, and Belgium at 8,339.
Due to the implications of this ongoing research, the researchers warn the public of taking vitamin D supplements. Because the hormone is not water-soluble, a person has a higher chance of overdose from vitamin D. Excessive levels of vitamin D can lead to hypercalcemia or calcium buildup in the bloodstream. It can cause frequent urination, vomiting, and weakness. Severe complications from the overdose include bone pain and calcium stones in the kidneys.