|Researchers found a connection between excess intake of Vitamin B and hip fracture / Photo Credit: Shutterstock|
B vitamins provide essential benefits to a person's overall bodily function. Most people, especially healthy ones, take them in high doses to increase their effect on energy levels, brain function, and cell metabolism. However, taking B vitamins in a high dosage doesn't necessarily enhance the effect on healthy individuals, meaning it should be taken only when a person has a vitamin B deficiency.
In fact, high doses of certain B vitamins—B6 and B12—can actually pose a more negative effect on the body. A new study suggests healthy women who take too many vitamins B6 and B12 are more likely to experience hip fractures than those who don't. The researchers say the results support previous studies suggesting that vitamin supplements should be taken with caution.
B vitamins and hip fractures
Earlier research found a link between vitamins B6 and B12 to a decreased risk of heart disease, although results were mixed and some studies also associated these vitamins to fractures in older adults.
In the cohort study, the researchers followed 75,846 American women for 21 years and conducted dietary surveys about every four years. They also recorded information on hip fracture incidence among the participants at the beginning of the study as well as data on the women's diet, AFP News reported via Yahoo! News.
The results were published in the journal JAMA Network Open, wherein the researchers concluded that excess intake of vitamins B6 and B12 supplements have been linked to increased risk of hip fracture. AFP News said the highest risk was found in women who took high doses of B6 and B12 together—47 percent higher compared to women who took a low intake of both vitamins.
Data indicated that 2,304 women developed hip fractures during the study and half of them had the fracture before turning 76.
The dosage in the study was at least 3.6 milligrams of B6 and 20 micrograms of B12—much higher than the recommended dietary allowances of 1.5 milligrams of B6 for women beyond 50 and 2.4 micrograms of B12 for women aged 14 and up, as per US dietary guidelines.
Unexpected adverse effects
Lead author Haakon Meyer from the University of Oslo, Norway said many people take supplements even without solid evidence of increased benefits, especially because high-dose vitamin supplements are easily accessible in drug stores and on the internet.
"Our results add to other reports suggesting that high-dose vitamin supplementation can lead to unexpected adverse effects," Meyers told Reuters via email. "Normal intakes of these vitamins, corresponding to recommended dietary allowances, were not associated with increased fracture risk."
However, the authors noted that the study wasn't designed to provide evidence if or how vitamin B6 and B12 intake contributes to risk for hip fractures. Reuters added that the study may not also indicate the outcome for all older American women since the participants were mostly white, insured, and middle-class women.
But the results still highlighted the importance of going through a checkup prior to taking any vitamin supplement, according to Karen Hansen from the University of Wisconsin School of Medicine & Public Health.
"Women should seek their primary care provider’s advice on whether to take a vitamin B supplement," Hansen, who was not involved in the study, told Reuters. "If the provider documents a vitamin deficiency, then a supplement is clearly warranted."
Noting the outcomes of previous studies, the researcher added that the intake of vitamin B6 and B12 "will not improve skeletal health and might even be harmful" without a documented deficiency.
Vitamin B still needed
Meyer said the study is "transferable to Norway" despite American women using more supplements compared to their Norwegian counterparts.
"We suspected this when we re-analyzed data from two major Norwegian studies in 2017," the lead author said, as per web-based medical and health news service Medical Express.
Using the same intervention, the two Norwegian studies also found an increased risk of hip fracture for participants who were given high doses of vitamin B compared to those who were given a placebo supplement. This finding has been confirmed by the recent American study.
|It is important to consult a doctor first before taking any supplements / Photo Credit: Shutterstock|
However, the researchers were quick to point out that vitamin B12 alone doesn't result in increased risk. They said some elderly people actually need extra vitamin B12 supplements—and there is no established evidence that the vitamin would increase the risk of hip fracture.
There is also no clear possible biological explanation for the findings in the recent study. Previous work suggests high concentrations of vitamin B6 may accelerate bone loss by counteracting the balancing effect of estrogens on steroid receptors.
"A recent paradox theory proposes that large doses of pyridoxine, the inactive form of vitamin B6 included in supplements and found in foods, inhibit the [vitamin's] active form pyridoxal phosphate," the researchers explained.
They added that there is also no clear explanation as to how vitamin B12 contributed to increased fracture risk.