- Preliminary research indicated that vitamin D may reduce the risk of cardiovascular disease and cancer.
- However, there have been a few large, high-quality randomized controlled trials (RCTs) to confirm this.
- The RCT recently examined the effects of vitamin D supplementation in Finland.
- It found no association between vitamin D supplementation and a reduced risk of cardiovascular disease or cancer.
Vitamin D helps the body
Several scientists are setting out to understand how vitamin D deficiency and supplementation can affect disease. according to
Over the past two years,
Two other areas of particular interest are the potential effects of vitamin D on cardiovascular disease and cancer risk. However, few randomized controlled trials have investigated this. These types of studies are the gold standard for determining causal relationships in scientific research.
A recent study appears in American Journal of Clinical Nutrition, goes a long way towards addressing this knowledge gap.
talk with Medical news todayVimal Karani, Professor of Nutritional Genetics and Nutritional Genetics at the University of Reading in the UK, confirmed a gap between the initial research and clinical trial results.
Professor Crane was not involved in the latest study but worked with some of its authors.
He explained that previous large epidemiological studies “have demonstrated a link between vitamin D deficiency and the risk of developing it.” [cardiovascular disease] traits in different ethnic groups.” This suggests that vitamin D supplementation may reduce the risk of cardiovascular disease, he said.
“However, clinical trials have not provided convincing evidence of the blood pressure lowering effect of vitamin D supplementation,” he continued.
Professor Crane said there could be a wide range of reasons for this, including “differences in sample size, duration of supplementation, supplement dose, age of participants, geographic location, sun exposure, and outcome measures.” Further research is needed to replicate findings in Multiple ethnic groups.
To provide more evidence for the relationship between vitamin D and cardiovascular disease and cancer, the researchers behind the current study conducted the Finnish Vitamin D trial.
This occurred between 2012 and 2018, and was double-blind, randomized, and placebo-controlled.
“When we started planning the trial, there was a lot of evidence from observational studies that vitamin D deficiency would be associated with almost all major chronic diseases, such as [cardiovascular disease], cancer, and type 2 diabetes, as well as mortality,” Dr. Jerky Virtanen said in an interview with Medical news today.
Dr. Virtanen is assistant professor of nutrition and public health at the University of Eastern Finland, and co-principal investigator on the study.
“Also, we have shown it among [the] In the eastern Finnish population, a low content of vitamin D in the body has been associated with an increased risk of death and disorders of glucose metabolism. However, these types of studies do not provide evidence of causation.”
At the time, there was little evidence from randomized controlled trials that improved [the] The state of vitamin D in the body with vitamin D supplementation reduces the risk of disease.”
“Therefore, our aim was to start a trial of long-term vitamin D supplementation in Finland, where vitamin D deficiency was highly prevalent due to the long winter, and to investigate whether vitamin D supplementation could reduce the risks of major chronic diseases and death. “
The researchers looked at data from 2,495 people, including male participants 60 or older and female participants who were past menopause and 65 or older. The participants also had no history of cardiovascular disease or cancer.
Participants either took a placebo, vitamin D at a dose of 1,600 international units (IU) each day, or vitamin D at a dose of 3,200 IU each day.
Compared to a placebo, the dose of vitamin D did not reduce the incidence of cardiovascular disease or cancer in this group, the team determined.
One factor that complicated this analysis was that participants tended to have high levels of vitamin D at the start of the study. The authors believe that this stems from the implementation of the policies for fortification of foods with vitamin D in Finland, which began in 2003-2011.
“It is possible that vitamin D supplementation does not provide significant health benefits, especially in populations where vitamin D status is already good at the start of the trial.”
– Dr. Jerky Virtanen
Virtanen explained that the “problem” of most large vitamin D supplement trials was that initial levels of vitamin D were too high in a large portion of the study groups.
“This may reflect the well-known fact that people who participate in these types of studies tend to be more health conscious and more concerned with their health, so they are, on average, healthier than the average population.”
“They may have a better diet and are more likely to take supplements and exercise, all of which are also linked to higher levels of vitamin D in the blood,” he said. MNT.
“Those who would benefit from vitamin D supplementation – that is, those with low blood levels of vitamin D – are a small minority in trials. It is difficult to target this deficient population, because for ethical reasons it would not be possible Screening subjects and only those with low levels of vitamin D accepted into the trial. It would not be ethical to keep part of the study population, the placebo group, deficient. [in] Vitamin D for several years.
MNT Speak with Professor Sean Strain, Dr Emir McSorley and Dr Pamela Magee from the Center for Nutrition Innovation for Food and Health at the University of Ulster in Northern Ireland.
They explained that despite low levels of recruitment — the study authors had hoped to recruit 30,000 participants — the results showed some signs that vitamin D had health benefits.
“Although recruitment was challenging and did not meet expectations, there was some indication that the investigated group had a lower proportion of both [cardiovascular disease] and cancer, compared to national statistics, which would have been collected prior to the division.”
“This may indicate that improvements in vitamin D status at the national level have benefits to the general health of the population in addition to known effects for bone and muscle health. Because of the low numbers assigned, the group may not be representative at the national level, and caution should be exercised,” the scientists said. when interpreting these results.
According to Professor Crane: “The unique feature of this RCT was the use of two different doses of vitamin D to see the effect of dose response over a 5-year period. Despite the higher doses, the study failed to see any effect of supplementation on reducing the incidence of [cardiovascular disease] and cancer. “
“The results have significant public health implications,” Professor Karani continued. However, the results cannot be generalized to other populations, given that [the] Finland has a population of
Dr. Virtanen said that while there is some evidence for broader health benefits from vitamin D supplementation, there are also conflicting results.
At the moment, there is no consensus [about] What would be the optimal intake of vitamin D and [whether it is] The same for all health outcomes and for all people. For example, there is
Although there is no evidence yet that vitamin D supplementation can prevent [SARS-CoV-2] infection, it is well documented that those, especially with the severe form of COVID-19, have low levels of vitamin D in their blood.”
“It is also possible that this is a result of [SARS-CoV-2] Infection rather than the cause, because acute infection is known to lead to low levels of vitamin D in the blood, and many COVID-19 patients are overweight or obese or have a chronic disease such as type 2 diabetes, all of which are linked to low serum levels. Vitamin D, explained Dr. Virtanen.
Professor Strain, Dr. Maxorley and Dr. Magee have highlighted the role that vitamin D may play in a healthy immune system.
“There is strong evidence recently that vitamin D supports your immune system, and given the global pandemic, it appears that people with vitamin D do not have as severe a response to COVID-19 as those who are deficient – and most importantly, recover faster.”
Vitamin D plays a key role in the health of the musculoskeletal system. Vitamin D can be obtained from sunlight and food sources. However, vitamin D supplementation may be required to meet the recommended dietary intake – 600 IU per day in the US for those ages 1 to 70, and 800 IU per day for those over 70 – in order to maintain sufficient standing.”
Supplementation may be particularly relevant in populations residing in northern latitudes, where vitamin D cannot be synthesized from sunlight during the winter months, and in populations who spend little time outdoors and/or obtain limited amounts of vitamin D from sources food.”
The scientists said, “It is very difficult to get vitamin D from eating food alone, unless that food is fortified with vitamin D.” Moreover, people with diseases that affect vitamin D absorption may need supplementation. Vitamin D).
Professor Strain, Dr. Maxorley, and Dr. Magee suggested that the research could be further developed by studying a population with low levels of vitamin D.
“This research should be conducted in an appropriate population, many of whom have low vitamin D levels and therefore could benefit from vitamin D supplementation.”
“It will be important to explore whether vitamin D supplementation can reduce the incidence of [cardiovascular disease] and cancers, as that would make a strong case for obligating vitamin D or promoting fortified foods in the population.”
“There is some sensational evidence that Finnish nationality [vitamin D] The immunization program has benefits by reducing the incidence of [cardiovascular disease] and cancers, as well as the expected beneficial effects on bone health.”
“Another very important area that needs further exploration is the link between adequate vitamin D status and a fully functioning immune system, especially in light of the current COVID-19 pandemic.”
As Professor Crane notes, “Conducting a similar randomized controlled trial with a longer duration of vitamin D supplementation is strongly warranted in ethnically diverse populations to see if the results of the current study can be generalized.”
Doctor. Virtanen said MNT His current focus is on further analysis of the results of the Finnish vitamin D trial.
“At the moment, we have no plans to start another trial of vitamin D, but of course we will publish many other results from the Finnish vitamin D trial, for example the effects [on] arrhythmia, infections, type 2 diabetes, falls and fractures, pain, [and] Mood changes.”