Having Low Vitamin D Levels is Risky for Dementia, New Study Finds

Did you know that low Vitamin D levels could also increase the risk of developing dementia?

One of the leading health problems in the UK, especially for older adults is dementia. There are more than 850,000 people who are diagnosed with the disease, and one in 14 people over the age of 65 have dementia. It is also estimated that by 2025, the number of people with dementia in the UK will be more than 1 million.

But there’s a particular vitamin that could prevent you from having dementia and other memory-related diseases? It also starts with the D.

Yes, taking vitamin D on a daily basis reduces the risk of developing dementia, particularly in women, according to one study. 

Researchers discovered that those who took supplements lived free of the disease for a longer period of time, with 40% fewer cases overall. Experts believe having low vitamin D increases the accumulation of amyloid plaques and tau, both of which have been linked to Alzheimer’s disease and dementia.

In this study, scientists from Exeter University and Calgary’s Hotchkiss Brain Institute in Canada examined data from the National Alzheimer’s Coordinating Centre in the United States.

Supplements were taken by approximately 4,600 (37%) of the participants, who had an average age of 71 and were dementia-free at the start of the trial.

During the study, some 2,696 people went on to be diagnosed with dementia over the next 10 years.

Approximately three-quarters (2,017) of them did not take supplements during that time period, while a quarter did (679).

According to the findings published in Alzheimer’s & Dementia, those who reported taking vitamin D supplements had 40% fewer cases of the disease.

Professor Zahinoor Ismail, of the University of Calgary and the University of Exeter, who led the research, said: ‘We know that vitamin D has some effects in the brain that could have implications for reducing dementia, however so far, research has yielded conflicting results.

‘Our findings give key insights into groups who might be specifically targeted for vitamin D supplementation.

‘Overall, we found evidence to suggest that earlier supplementation might be particularly beneficial, before the onset of cognitive decline.’

How does low Vitamin D level affect the brain?

Vitamin D, also known as the “sunshine vitamin,” is produced in our skin when we are exposed to sunlight. And, while vitamin D is well known for promoting bone health and regulating vital calcium levels (hence its inclusion in milk), it does much more.

Scientists have now linked this fat-soluble nutrient’s hormonelike activity to a variety of bodily functions, including brain function.

Vitamin D is a calcium-regulating hormone with numerous functions in many tissues, including the brain. A growing body of evidence suggests that vitamin D may play a role in cognitive function maintenance and that vitamin D deficiency may hasten age-related cognitive decline.

“We know there are receptors for vitamin D throughout the central nervous system and in the hippocampus,” said Robert J. Przybelski, a doctor and research scientist at the University of Wisconsin School of Medicine and Public Health. “We also know vitamin D activates and deactivates enzymes in the brain and the cerebrospinal fluid that are involved in neurotransmitter synthesis and nerve growth.” 

What are the Types of Vitamin D?

Few food contain vitamin D naturally, though some are fortified with the vitamin. Because it is difficult to consume enough vitamin D through food, most people prefer to take a supplement

There are two types of vitamin D supplements: vitamin D2 (“ergocalciferol” or pre-vitamin D) and vitamin D3 (“cholecalciferol”).

Both are naturally occurring forms that are produced in the presence of ultraviolet-B (UVB) rays from the sun, hence the nickname “the sunshine vitamin,” but D2 is produced in plants and fungi and D3 in animals, including humans.

Where can we get Vitamin D?

1. Food Sources

In terms of diet and nutrition, the best sources are the flesh of fatty fish and fish liver oils.

Smaller amounts are found in egg yolks, cheese, and beef liver. Certain mushrooms contain some vitamin D2; in addition some commercially sold mushrooms contain higher amounts of D2 due to intentionally being exposed to high amounts of ultraviolet light.

Many foods and supplements are fortified with vitamin D like dairy products and cereals.

  • Cod liver oil
  • Salmon
  • Swordfish
  • Tuna fish
  • Orange juice fortified with vitamin D
  • Dairy and plant milks fortified with vitamin D
  • Sardines
  • Beef liver
  • Egg yolk
  • Fortified cereals

2. Ultraviolet Light

Vitamin D3 can be formed when a chemical reaction occurs in human skin, when a steroid called 7-dehydrocholesterol is broken down by the sun’s UVB light or so-called “tanning” rays. The amount of the vitamin absorbed can vary widely. The following are conditions that decrease exposure to UVB light and therefore lessen vitamin D absorption:

  • Use of sunscreen; correctly applied sunscreen can reduce vitamin D absorption by more than 90%.
  • Wearing full clothing that covers the skin.
  • Spending limited time outdoors.
  • Darker skin tones due to having higher amounts of the pigment melanin, which acts as a type of natural sunscreen.
  • Older ages when there is a decrease in 7-dehydrocholesterol levels and changes in skin, and a population that is likely to spend more time indoors.

What are the effects of Vitamin D to older people?

Older adults have a greater need for vitamin D due to being at a higher risk for conditions like osteoporosis, cardiovascular disease, and cancer. There are several ways for older adults to supplement vitamin D naturally, but sunshine is one of the best natural sources of vitamin D.

Because the skin of older people is less efficient at converting sunlight into Vitamin D, they are more likely to be deficient and reliant on other sources.

While both sexes benefited from supplements, the effects were greatest in women and people with normal cognition, compared to those who reported signs of mild cognitive impairment – changes in cognition that have been linked to an increased risk of dementia.

Experts believe the greater effects in women may be due to lower levels of oestrogen, which is linked to vitamin D activation, during menopause. This could result in greater effects from taking the vitamin, which is frequently recommended to women due to links to other health benefits such as bone health.