Vitamin D: Your Brain’s Ally against Alzheimer’s and Dementia

Few people realise that vitamin D acts more like a brain fat than a vitamin – and your risk of cognitive decline can soar by up to 19 times if your levels are low. Often known as the sunshine vitamin, it is in fact a vital brain nutrient: helping neurons communicate, calming inflammation and defending against oxidative stress – all crucial for protecting memory, mood and long-term cognitive health. This highlights the important connection between vitamin D and dementia.

When vitamin D levels drop, the effects on the brain are striking.

Studies show that people with low vitamin D are far more likely to experience cognitive decline and dementia, while those with optimal levels have up to four times lower risk of developing Alzheimer’s disease. In older adults, falling vitamin D often mirrors worsening memory – yet the simple act of supplementing can reduce risk by a third.

Vitamin D and Dementia

Low vitamin D levels are significantly linked to a higher risk of dementia and cognitive decline. One notable study carried out in France highlights an astonishing finding: older women with vitamin D deficiency were approximately 19 times more likely to develop dementia within seven years compared to those without vitamin D deficiency. This research backs up several previous studies, including one that tracked 1,658 elderly adults for over five and a half years, concluding:

“Vitamin D deficiency is associated with a substantially increased risk of all-cause dementia and Alzheimer’s disease.”

Understanding the Impact of Vitamin D on Overall Health

The impact of Vitamin D deficiency is a significant one, with links to not only dementia but also conditions such as osteoporosis, cardiovascular disease, cancer, stroke, diabetes, schizophrenia, psychosis, and autism , as well as behavioural problems in adolescents and children with ADHD.

How to Sustain Optimal Vitamin D Levels

Of course, we can get vitamin D from our diet: oily fish, including salmon, mackerel, sardines, egg yolks, red meat, and liver, are all excellent sources. However, our bodies struggle to produce and maintain optimal vitamin D levels as we age, even with a good diet. 

Our reliance on the sun, our natural provider of Vitamin D, is also compromised, especially in the Northern Hemisphere, as we begin to emerge from the long winter months and not, as yet, fully into the bright embrace of summer. It’s no wonder that our bodies are left vulnerable to notable decreases in vitamin D.  

What Exactly is Vitamin D Deficiency?

Deficiency is defined as serum 25(OH)D concentrations of less than 50 nmol/L. Our vitamin D expert, Dr William Grant, says:

“All the evidence regarding cardio-metabolic diseases, cancer, diabetes, infectious diseases, and pregnancy outcomes shows that you need a blood level of vitamin D above 75 nmol/L to be healthy, and the same is proving true for the brain.” 

This optimal level is impossible to achieve without supplementation in the winter. I recommend every adult and teenager supplements themselves with at least 1000 to 3000iu per day from October to March in line with a recent review by 35 vitamin D researchers. The degree of obesity, darker skin colour and living further North increases need.

Supplementation: a Shield Against Risk?

According to recent research, turning to vitamin D supplements could reduce the risk of dementia.   Researchers at the University of Calgary’s Hotchkiss Brain Institute in Canada and the University of Exeter in the UK explored the relationship between vitamin D supplementation and dementia in 12,388 participants with a mean age of 71.  They were dementia-free when they signed up. Of the group, 37 percent (4,637) took vitamin D supplements. In the study, the team found that taking vitamin D was associated with living dementia-free for longer, and they also found 40 percent fewer dementia diagnoses in the group who took supplements.

How to Boost your vitamin D naturally.

• Spend 15–20 minutes outdoors daily if you are in summer or live near the equator (without sunscreen on arms or legs, when the sun is high). Avoid peak sun times.
• Eat oily fish twice a week – salmon, mackerel, sardines or trout.
• Add egg yolks, mushrooms, and fortified dairy alternatives to your meals.
• Supplement between 1,000–3,000 iu daily from October to March (and year-round if you have darker skin or live in northern latitudes). Find out more about supplements here