Судлаачид дунд эргэм насанд D аминдэмийн хэмжээ хэвийн байх нь тархинд Альцгеймерийн өвчний шинж тэмдэг болох хортой уургийн хуримтлал үүсэхийг бууруулж болохыг илрүүлжээ.
Neurology Open Access сэтгүүлд нийтлэгдсэн шинэ судалгаагаар дунд эргэм насны хүмүүсийн D аминдэмийн түвшин ирээдүйн тархины эрүүл мэндэд чухал нөлөөтэй байж болохыг тогтоосон байна. University of Galway-ийн мэдрэлийн эмч Эмер МакГрат болон түүний баг АНУ-ын Framingham Heart Study судалгааны 793 оролцогчийн мэдээлэлд дүн шинжилгээ хийжээ. Оролцогчдын дундаж нас нь 39 байсан бөгөөд тэдний цусан дахь D аминдэмийн хэмжээг эхний шатанд шинжилж, 16 жилийн дараа тархины PET шинжилгээгээр Альцгеймерийн өвчний үед хуримтлагддаг “тау” уургийн илрэлийг хянасан байна.
Судалгааны үр дүнгээр дунд эргэм насандаа D аминдэмийн түвшин өндөр байсан хүмүүс 16 жилийн дараа тархинд тау уургийн хуримтлал багатай байжээ. Гэсэн хэдий ч судалгаа нь ажиглалтын шинж чанартай тул D аминдэм нь тау уургийн үүсэлтийг шууд бууруулсан гэж батлах боломжгүй юм. Мөн амилоид бета уургийн хувьд ямар нэгэн холбоо хамаарал илрээгүй байна.
Өмнө нь 70-аас дээш насны хүмүүст хийсэн судалгаагаар D аминдэмийн нэмэлт бүтээгдэхүүн нь тау уургийн хуримтлалд нөлөөлөөгүй болох нь тогтоогдсон. Судлаачид залуу болон дунд эргэм насны хүмүүст өвчин үүсэхээс өмнө илүү их боломж байгаа тул D аминдэмийн нэмэлт нь урьдчилан сэргийлэх нөлөөтэй байж болохыг үгүйсгээгүй юм. Энэхүү таамаглалыг батлахын тулд ирээдүйд эмнэлзүйн туршилтуудыг хийх шаардлагатай гэж үзэж байна.
Дэлгэрэнгүйг эх сурвалжаас харах
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The benefits of vitamin D are many, with research suggesting it plays an important role in several facets of our health, from boosting our immunity to helping us counter harmful diseases.
As long as we don’t have too much of it, vitamin D is an essential part of a healthy body. But there’s still a lot we don’t know about just how far its goodness extends.
In recent years, numerous studies have demonstrated that low levels of vitamin D in older adults are associated with increased risk of cognitive impairment and clinical dementia.
What has remained unclear, though, is whether vitamin D levels might protect the brain in midlife, and if middle-aged adults with healthy vitamin D levels might stand a better chance of avoiding conditions like Alzheimer’s disease as they age.
In a study published in Neurology Open Access this year, we got an answer, with researchers finding that healthy vitamin D levels in midlife are linked to reduced levels of toxic tau protein deposits – a known Alzheimer’s biomarker – when people grow older.
“Vitamin D in mid-life could be an important factor to protect future brain health,” says neurologist and senior author Emer McGrath from the University of Galway in Ireland.
“While previous research has linked low vitamin D in adults over 70 with an increased risk of dementia, this study is among the first to look at younger adults at mid-life, around the average age of 39.”
In the study, researchers analyzed a segment of participants from the US-based Framingham Heart Study, looking at a sample of 793 men and women, none of whom had dementia.
When the participants were 39 years of age on average, they had their vitamin D levels analyzed from a blood test.
About 16 years later, around 430 of the same group participated in brain positron emission tomography (PET) scans, assessing them for signs of tau or amyloid beta, protein clumps long implicated in Alzheimer’s disease.
While no correlation was found for amyloid beta in the Framingham cohort, analysis showed participants with higher levels of vitamin D at the outset of the experiment tended to show lower tau deposits at the 16-year follow-up – a discovery the researchers claim to be a first.
“To the best of our knowledge, there have been no previous studies evaluating an association between serum vitamin D and neuroimaging markers of preclinical dementia,” the authors write in their paper.
“Notably, our study included individuals in early midlife, when there is greater opportunity for risk modification.”
Due to the observational nature of the study, we can’t say for sure that higher vitamin D levels at middle age somehow reduced the formation of harmful tau proteins.
But the results suggest it’s certainly a possibility – and it’s something researchers could test for in future experiments.
“While these findings are very interesting, they only demonstrate an association between vitamin D and early signs of dementia in the brain,” McGrath says.
“Further studies, for example, a clinical trial, will be required to determine if vitamin D supplements could prevent dementia.”
Previous research looking at the effects of vitamin D supplementation on tau levels found no effect based on a one-year nutritional intervention.
Related: New ‘Unifying Theory’ May Explain How Alzheimer’s Emerges in The Brain
But it’s worth noting that French trial involved adults aged 70 years or older, and with self-reported memory complaints.
It’s possible, McGrath and her colleagues think, that the same kind of intervention could have a protective effect on significantly younger people in midlife, before either harmful tau pathology or Alzheimer’s symptoms have had a chance to emerge.
“Supplementation with higher doses of vitamin D, and/or over longer periods of time in younger, cognitively healthy individuals may be beneficial, as the window of opportunity for disease modification is greater,” the team explains.
“However, this will require formal testing in clinical trials.”
The findings are reported in Neurology Open Access.
This article was fact-checked by Clare Watson and edited by Clare Watson. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.
