Vitamin D Might Help Prevent Early-Onset Colon Cancer

Foods rich in vitamin D may help protect younger adults against colon cancer, researchers report.

While colon cancer is decreasing overall, cases among younger adults have been on the rise. The trends dovetail with a decline in vitamin D intake from foods such as fish, mushrooms, eggs and milk.

There is growing evidence of a link between vitamin D and risk of colon cancer death, but little research on whether vitamin D intake is associated with the risk of young-onset (before age 50) colon cancer.

“Because vitamin D deficiency has been steadily increasing over the past few years, we wondered whether this could be contributing to the rising rates” of colon cancer in younger people, said study co-senior author Dr. Kimmie Ng, director of the Young-Onset Colorectal Cancer Center at Dana-Farber Cancer Institute in Boston.

The study found that vitamin D intake of 300 IU per day or more — roughly equivalent to three 8-ounce glasses of milk — was associated with roughly a 50% lower risk of developing young-onset colon cancer.

Higher vitamin D intake were also associated with a lower risk of potentially precancerous colon polyps detected before age 50.

The findings are based on data from more than 94,000 women who were part of a long-term study that began in 1989. They were 25 to 42 years of age when the study began.

The study — recently published online in the journal Gastroenterology — is the first to make the connection between vitamin D levels and risk of young-onset colon cancer, researchers said.

They didn’t find a significant link between vitamin D intake and colon cancer risk after age 50, and they said more study is needed to determine if vitamin D actually provides greater protection against young-onset colon cancer than against it later on.

“Our results further support that vitamin D may be important in younger adults for health and possibly colorectal cancer prevention,” Ng said.

She said it is critical to understand the risk factors associated with young-onset colon cancer so informed decisions about lifestyle and diet can be made and high-risk individuals can receive earlier screening.

The findings could lead to recommendations for higher vitamin D intake as an inexpensive addition to screening tests to prevent colon cancer in adults under 50, researchers said.

Source: HealthDay

Study: Fish Oil, Vitamin D Won’t Prevent Atrial Fibrillation

For people hoping to prevent the heart rhythm disorder known as “a-fib,” new research shows that taking vitamin D or fish oil supplements won’t help.

A-fib, also known as atrial fibrillation, affects more than 33 million people worldwide and is the most common type of abnormal heart rhythm. It can cause symptoms that affect a person’s quality of life, result in blood clots that can cause a stroke, and also lead to heart failure.

For the study, the researchers examined whether taking vitamin D supplements or omega-3 fatty acids found in fish oil might affect different kinds of a-fib, and whether some patients would be more likely to benefit or be harmed by the supplements.

Overall, the results were mostly consistent across the different types of a-fib and patient groups, according to lead author Dr. Christine Albert and colleagues. Albert is chair of the cardiology department at Smidt Heart Institute in Los Angeles.

The study, published March 16 in the Journal of the American Medical Association, follows a presentation by Albert at an American Heart Association conference last year.

“Our recommendation remains the same,” she said in a JAMA Network news release. “We do not support taking fish oil or vitamin D supplements to prevent atrial fibrillation.”

However, “unlike other recent trials that found increased risks of atrial fibrillation with higher-dose omega-3 fatty acid supplements, our study did not find a significantly increased risk of atrial fibrillation with one gram of fish oil per day, which is good news for individuals taking low-dose fish oil for other health conditions,” Albert said.

Her team also found that vitamin D supplements at 2,000 international units per day did not increase a-fib risk.

Source: HealthDay

Study: High-Dose Vitamin D Won’t Prevent Seniors’ Falls

High doses of vitamin D may increase seniors’ risk of falls, rather than reduce it, according to a new study.

Preliminary studies suggested vitamin D may increase muscle strength and improve balance, so Johns Hopkins researchers investigated whether high doses of vitamin D might reduce the risk of falls in people aged 70 and older.

But the investigators found that large doses of vitamin D supplements were no better at preventing falls in this age group than a low dose.

“There’s no benefit of higher doses but several signals of potential harm,” study author Dr. Lawrence Appel said in a Hopkins news release.

“A lot of people think if a little bit is helpful, a lot will be better. But for some vitamins, high-dose supplements pose more risks than benefits. There’s a real possibility that higher doses of vitamin D increase the risk and severity of falls,” said Appel, a professor of medicine with joint appointments in epidemiology, international health and nursing.

Taking 1,000 or more international units per day (IU/day), equivalent to 25 micrograms/day of vitamin D, was no better than 200 IU/day at preventing falls, according to the study, which was funded by the U.S. National Institute on Aging.

The results were published Dec. 8 in the journal Annals of Internal Medicine.

The researchers also found that vitamin D supplement doses of 2,000 and 4,000 IU/day seemed to increase the risk and severity of falls compared with 1,000 IU/day, a relatively common dose for a pure vitamin D supplement.

Another finding was that serious falls and falls that required hospitalization occurred more often in older people who took 1,000 or more IU/day than in those who took 200 IU/day (about half the typical dose found in multivitamins).

Older folks should talk with their doctors about their fall risk and vitamin D levels in order to determine whether or not to continue taking vitamin D supplements, Appel recommended.

Source: HealthDay

Study Reveals Connection Between Gut Bacteria and Vitamin D Levels

Heather Buschman wrote . . . . . . . . .

Our gut microbiomes — the many bacteria, viruses and other microbes living in our digestive tracts — play important roles in our health and risk for disease in ways that are only beginning to be recognized.

University of California San Diego researchers and collaborators recently demonstrated in older men that the makeup of a person’s gut microbiome is linked to their levels of active vitamin D, a hormone important for bone health and immunity.

The study, published November 26, 2020 in Nature Communications, also revealed a new understanding of vitamin D and how it’s typically measured.

Vitamin D can take several different forms, but standard blood tests detect only one, an inactive precursor that can be stored by the body. To use vitamin D, the body must metabolize the precursor into an active form.

“We were surprised to find that microbiome diversity — the variety of bacteria types in a person’s gut — was closely associated with active vitamin D, but not the precursor form,” said senior author Deborah Kado, MD, director of the Osteoporosis Clinic at UC San Diego Health. “Greater gut microbiome diversity is thought to be associated with better health in general.”

Kado led the study for the National Institute on Aging-funded Osteoporotic Fractures in Men (MrOS) Study Research Group, a large, multi-site effort that started in 2000. She teamed up with Rob Knight, PhD, professor and director of the Center for Microbiome Innovation at UC San Diego, and co-first authors Robert L. Thomas, MD, PhD, fellow in the Division of Endocrinology at UC San Diego School of Medicine, and Serene Lingjing Jiang, graduate student in the Biostatistics Program at Herbert Wertheim School of Public Health and Human Longevity Sciences.

Multiple studies have suggested that people with low vitamin D levels are at higher risk for cancer, heart disease, worse COVID-19 infections and other diseases. Yet the largest randomized clinical trial to date, with more than 25,000 adults, concluded that taking vitamin D supplements has no effect on health outcomes, including heart disease, cancer or even bone health.

“Our study suggests that might be because these studies measured only the precursor form of vitamin D, rather than active hormone,” said Kado, who is also professor at UC San Diego School of Medicine and Herbert Wertheim School of Public Health. “Measures of vitamin D formation and breakdown may be better indicators of underlying health issues, and who might best respond to vitamin D supplementation.”

The team analyzed stool and blood samples contributed by 567 men participating in MrOS. The participants live in six cities around the United States, their mean age was 84 and most reported being in good or excellent health. The researchers used a technique called 16s rRNA sequencing to identify and quantify the types of bacteria in each stool sample based on unique genetic identifiers. They used a method known as LC-MSMS to quantify vitamin D metabolites (the precursor, active hormone and the breakdown product) in each participant’s blood serum.

In addition to discovering a link between active vitamin D and overall microbiome diversity, the researchers also noted that 12 particular types of bacteria appeared more often in the gut microbiomes of men with lots of active vitamin D. Most of those 12 bacteria produce butyrate, a beneficial fatty acid that helps maintain gut lining health.

“Gut microbiomes are really complex and vary a lot from person to person,” Jiang said. “When we do find associations, they aren’t usually as distinct as we found here.”

Because they live in different regions of the U.S., the men in the study are exposed to differing amounts of sunlight, a source of vitamin D. As expected, men who lived in San Diego, California got the most sun, and they also had the most precursor form of vitamin D.

But the team unexpectedly found no correlations between where men lived and their levels of active vitamin D hormone.

“It seems like it doesn’t matter how much vitamin D you get through sunlight or supplementation, nor how much your body can store,” Kado said. “It matters how well your body is able to metabolize that into active vitamin D, and maybe that’s what clinical trials need to measure in order to get a more accurate picture of the vitamin’s role in health.”

“We often find in medicine that more is not necessarily better,” Thomas added. “So in this case, maybe it’s not how much vitamin D you supplement with, but how you encourage your body to use it.”

Kado pointed out that the study relied on a single snapshot in time of the microbes and vitamin D found in participants’ blood and stool, and those factors can fluctuate over time depending on a person’s environment, diet, sleep habits, medications and more. According to the team, more studies are needed to better understand the part bacteria play in vitamin D metabolism, and to determine whether intervening at the microbiome level could be used to augment current treatments to improve bone and possibly other health outcomes.

Source: UC San Diego

Vitamin D Levels During Pregnancy Linked with Child IQ

Kathryn Mueller wrote . . . . . . . . .

Vitamin D is a critical nutrient and has many important functions in the body. A mother’s vitamin D supply is passed to her baby in utero and helps regulate processes including brain development. A study published today in The Journal of Nutrition showed that mothers’ vitamin D levels during pregnancy were associated with their children’s IQ, suggesting that higher vitamin D levels in pregnancy may lead to greater childhood IQ scores. The study also identified significantly lower levels of vitamin D levels among Black pregnant women.

Melissa Melough, the lead author of the study and research scientist in the Department of Child Health, Behavior, and Development at Seattle Children’s Research Institute, says vitamin D deficiency is common among the general population as well as pregnant women, but notes that Black women are at greater risk. Melough says she hopes the study will help health care providers address disparities among women of color and those who are at higher risk for vitamin D deficiency.

“Melanin pigment protects the skin against sun damage, but by blocking UV rays, melanin also reduces vitamin D production in the skin. Because of this, we weren’t surprised to see high rates of vitamin D deficiency among Black pregnant women in our study. Even though many pregnant women take a prenatal vitamin, this may not correct an existing vitamin D deficiency,” Melough said. “I hope our work brings greater awareness to this problem, shows the long-lasting implications of prenatal vitamin D for the child and their neurocognitive development, and highlights that there are certain groups providers should be paying closer attention to. Wide-spread testing of vitamin D levels is not generally recommended, but I think health care providers should be looking out for those who are at higher risk, including Black women.”

Addressing disparities

According to Melough, as many as 80% of Black pregnant women in the U.S. may be deficient in vitamin D. Of the women who participated in the study, approximately 46% of the mothers were deficient in vitamin D during their pregnancy, and vitamin D levels were lower among Black women compared to White women.

Melough and her co-authors used data from a cohort in Tennessee called the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) study. CANDLE researchers recruited pregnant women to join the study starting in 2006 and collected information over time about their children’s health and development.

After controlling for several other factors related to IQ, higher vitamin D levels in pregnancy were associated with higher IQ in children ages 4 to 6 years old. Although observational studies like this one cannot prove causation, Melough believes her findings have important implications and warrant further research.

Vitamin D deficiency

“Vitamin D deficiency is quite prevalent,” Melough said. “The good news is there is a relatively easy solution. It can be difficult to get adequate vitamin D through diet, and not everyone can make up for this gap through sun exposure, so a good solution is to take a supplement.”

The recommended daily intake of vitamin D is 600 international units (IU). On average, Americans consume less than 200 IU in their diet, and so if people aren’t making up that gap through sun exposure or supplementation, Melough says people will probably become deficient. Foods that contain higher levels of vitamin D include fatty fish, eggs and fortified sources like cow’s milk and breakfast cereals. However, Melough notes that vitamin D is one of the most difficult nutrients to get in adequate amounts from our diets.

Additional research is needed to determine the optimal levels of vitamin D in pregnancy, but Melough hopes this study will help to develop nutritional recommendations for pregnant women. Especially among Black women and those at high risk for vitamin D deficiency, nutritional supplementation and screening may be an impactful strategy for reducing health disparities.

Key takeaways

Melough says there are three key takeaways from the study:

  • Vitamin D deficiency is common during pregnancy, and Black women are at greater risk because melanin pigment in the skin reduces production of vitamin D
  • Higher vitamin D levels among mothers during pregnancy may promote brain development and lead to higher childhood IQ scores
  • Screening and nutritional supplementation may correct vitamin D deficiency for those at high risk and promote cognitive function in offspring

“I want people to know that it’s a common problem and can affect children’s development,” Melough said. “Vitamin D deficiency can occur even if you eat a healthy diet. Sometimes it’s related to our lifestyles, skin pigmentation or other factors outside of our control.”

Source: Seattle Children’s