Vitamin D is present in most people's bodies at a healthy level. The compound's purported ability to combat anything from cancer to depression has been greatly exaggerated, according to recent studies, Scientific American reports.
There was a time when vitamin D seemed to be a genuine miracle cure-all. A century ago, it was acknowledged as a treatment for rickets, a disorder affecting children that results in brittle and misshapen bones. Cancer, heart disease, dementia, depression, diabetes, autoimmune diseases, fractures, respiratory infections, and Parkinson's disease were all linked to low vitamin D levels, according to a mountain of research that started piling up in the early 2000s. Increasing our intake of this basic vitamin—which our bodies produce when exposed to sunlight and which we may supplement—was rationally believed to have the power to heal nearly every illness.
The Vitamin D Cure has been the title of at least two publications, and there are many more with terms like "revolution" and "miracle" in their names. The idea that our vitamin intake was inadequate was also becoming more of a worry. Diane Sawyer, a reporter for Good Morning America, started the piece by saying that 100 million Americans were lacking something. She was joined by Dr. Oz, who informed his audience that a simple blood test may reveal their vitamin D status. Sunlight, he explained, is the vitamin's finest source. He also suggested taking pills or cod liver oil in case that wasn't enough.
Endocrinologist and epidemiologist JoAnn Manson of Harvard Medical School was a principal investigator on several of the largest vitamin D trials that have ever been conducted. She claims that many celebrities and vitamin firms had high hopes that vitamin D may be a miracle drug. Both the number of people tested for vitamin D and the sales of pills containing it skyrocketed.
Afterwards, everything snapped. Despite the fact that vitamin D deficiency has been associated with a host of health issues in several studies, the miraculous supplement was a resounding failure when used to either prevent or cure these disorders. It started to seem like a pipe dream that our lives would improve if we all took more vitamin D. It also fell apart the notion that vitamin D insufficiency was common. It became clear that preconceived conceptions about what defines a deficit were seriously flawed. The majority of the population was already consuming an adequate amount of the vitamin, according to the national population sample.
It's undeniable that vitamin D is crucial to good health. It aids in the absorption and retention of calcium and phosphorus, two minerals essential for bone formation. Supplements may not be necessary for the majority of individuals, yet there are a few exceptions to this rule. These include breastfed infants and those with certain medical conditions.
Vitamin D's meteoric rise to miracle status and subsequent fall to Earth provides a cautionary tale about the winding road to scientific enlightenment. Additionally, it serves as a reminder to approach scientific findings with a sense of modesty. In the end, everything boils down to how knowledge is refined through time and how science is inherently self-correcting.
Sunlight was the primary source of vitamin D for the majority of human history. It turns out that, similar to plants, people may use a process called photosynthesis to convert UV light into something our bodies require.
Hit by the powerful ultraviolet B (UVB) rays, a chemical in your skin known as a sterol is transformed into a precursor to vitamin D. Further processing transforms this molecule into a vitamin form that enhances mineralization of bones and boosts intestinal calcium absorption. Vitamin D appears to have anti-inflammatory and immune system enhancing properties as well. One way it accomplishes these goals is by reducing the accumulation of proinflammatory cells and affecting the synthesis of inflammatory chemicals. Scientists are trying to figure out if vitamin D might help COVID patients avoid potentially fatal inflammatory responses.
During the Industrial Revolution, when smog and smoke made it harder for humans to make vitamin D, rickets grew more common as children spent more time in the shade of densely populated cities and less time outside. Researchers had shown regional variations in rickets occurrence by the late 1800s, suggesting a potential connection to sunshine.
The naming of vitamin D-rich cod liver oil was done by scientist Elmer McCollum of Johns Hopkins University in the 1920s. In 1928, the biosynthesis of vitamin D from sunshine was demonstrated by German chemist Adolf Otto Reinhold Windaus, who was awarded the Nobel Prize in Chemistry. As soon as this mysterious molecule was referred to as a vitamin, it took on an air of benignancy. Originating from the Latin words "vita" (meaning "life") and "amine" (meaning "building blocks of life, amino acids"), the Polish scientist Casimir Funk first used the term "vitamin" in his work. According to Catherine Price, author of Vitamania: How Vitamins Revolutionised the Way We Think about Food, the phrase had "an aura of safety and health" associated with it.
When Harry Steenbock, a former student of McCollum's at the University of Wisconsin–Madison, found that he could make vitamin D in rats and their food by exposing them to ultraviolet light, the practice of adding vitamin D to food began. Sterol molecules, which can be found in the cells of animals, plants, and fungi, undergo a conversion process when the rays reach them. As an example, the vitamin D content of chicken meat and egg yolks can be increased by subjecting them to ultraviolet B radiation. Irradiated lanolin, a fat extracted from sheep's wool, is the primary source of vitamin D in contemporary dietary supplements. The addition of irradiation fat extract to milk or irradiated feed increased D levels in dairy cows, according to Steenbock. Many people get their vitamin D from fortified milk and other dairy products, which also include the vitamin in a form derived from lanolin.
Joseph Schlitz Brewing Company's "Sunshine Vitamin D" beer was first produced in 1936. Beer has health benefits, but "SCHLITZ, with SUNSHINE Vitamin D, is extra good for you!" the commercials announced. Enjoy good health with every sip. Corona Sunbrew, a nonalcoholic beer enhanced with vitamin D, was launched in 2022 by the Corona beer brand. If that sounds dated, think about it.
Yet, beer is not a nutritious beverage. "The natural, evolutionarily appropriate way to get vitamin D is through synthesis in your skin," explains Anastassios Pittas, chief of the division of endocrinology, diabetes and metabolism at Tufts Medical Centre. However, a sunburn is not necessary for that. It turns out that getting enough vitamin D from the sun doesn't require intense exposure. Between April and October, a person in Boston with 25% exposed skin would require three to eight minutes of sunlight daily, according to a research conducted in 2010. Naturally, at some latitudes, even this amount of sunshine can be hard to get by during the winter.
Your body can handle this kind of variance, thankfully. Vitamin D is stored by your liver and adipose tissue for when you need it, according to Pittas. That being said, a large dose may not be required daily. If you don't get much vitamin D from the sun over the winter, Pittas explains, you may still have enough circulating from your liver to keep your calcium and phosphorus levels appropriate because your vitamin D cache usually lasts approximately 10 to 12 weeks. He believes that a winter dip is normal, but that it should only be cause for concern if your vitamin D levels are already dangerously low.
When research revealed that vitamin D supplementation may reduce the risk of several diseases and disorders, including diabetes, cancer, heart disease, and cancer, interest in increasing one's vitamin D intake skyrocketed.
An issue with this evidence is that it is primarily derived from observational studies, which, according to Manson, cannot demonstrate cause and effect and may lead to deceptive conclusions. These research evaluated vitamin D status across individuals with and without a specific ailment or sought to establish connections between vitamin D levels and a specific health issue. For example, a 2008 branch of the Framingham Heart Study tracked about 1,700 individuals who did not have a history of cardiovascular illness for approximately five years. Those individuals were shown to have a higher risk of developing heart disease in those who had low vitamin D levels. Vitamin D was the subject of much speculation and enthusiasm as a result of the findings, according to Manson.
It seems that D levels were also associated with diabetes. In 2010, researchers in Tromsø, Norway, tracked about 6,100 individuals for 11 years. Before their body mass was included, there was an inverse link between their vitamin D blood levels and the incidence of type 2 diabetes. In other words, higher D levels were associated with fewer incidences of diabetes. Similarly, the highest D-level participants had the lowest five-year chance of acquiring diabetes, according to a 2011 study of almost 6,500 persons in Australia.
The main problem with these observational studies is that they can only show that vitamin D and diseases occur together; they cannot establish a cause-and-effect relationship, or even if one does exist, they cannot say which way it may go. The correlation between a person's wealth and their car's price is strong, but it doesn't imply that purchasing a high-priced car will magically increase your fortune.
The problem won't be solved just because there is an association, according to Dr. Leila Kahwati, associate director of the Research Triangle Institute-University of North Carolina Evidence-based Practice Centre. Additional variables may be involved. Vitamin D supplement users may be more health-conscious and take more precautions to avoid illness, whereas those with preexisting conditions are likely to limit their time in the sun to avoid further depletion of their vitamin D stores.
The most persuasive form of medical evidence, according to Dr. Jodi Segal of Johns Hopkins University's School of Public Health's Centre for Health Services and Outcomes Research, is a randomised controlled trial, in which a group of people are recruited and then given either a real treatment or a placebo. It is considerably more probable that the intervention, and not some other variable, is responsible for any differences between the study and placebo groups when the design is randomised.
Manson and her colleagues began VITAL, the biggest and most comprehensive randomised vitamin D experiment in the world, in 2009. Approximately 26,000 persons in good health were monitored for an average of 5.3 years in this randomised controlled trial of vitamin D supplementation (2,000 IU) vs a placebo. Twenty percent of the volunteers were Black, and the gender distribution was nearly evenly between the sexes. The primary goal of the research was to determine if taking vitamin D supplements reduced the risk of cancer and cardiovascular disease.
It was shocking to hear the results. Among the many unanticipated effects of vitamin D that the trial failed to find was any improvement in cancer or heart disease rates, as well as in cognitive function, atrial fibrillation, body composition, migraine frequency, stroke outcomes, age-related macular degeneration, knee pain, or the risk of bone fractures. Manson claims that several individuals were "really surprised" by the discovery of fractures.
Extra vitamin D also failed to reduce the risk of diabetes. The 2019 New England Journal of Medicine trial, which Pittas and colleagues conducted, randomly assigned over 2,400 individuals at risk for diabetes to take either 4,000 IU of vitamin D or a placebo on a daily basis. Approximately the same amount of individuals in both groups eventually became ill after 2.5 years.
Participants in the Vitamin D Assessment Study (ViDA) ranged in age from 50 to 84 and were randomly assigned to receive either a placebo or a monthly dosage of 200,000 IU of vitamin D, which is significantly greater than the recommended daily amount. In terms of cardiovascular disease, acute respiratory infections, non-spinal fractures, falls, and all types of cancer, the study indicated that levels had no impact. Vitamin D supplementation was not associated with a lower risk of death or invasive malignancy in other studies. Endocrinologist Clifford Rosen of the Maine Medicine Center's Research Institute states that by 2020 or so, these and other findings from VITAL have contributed to a rising level of scepticism regarding vitamin D. /BGNES
