Until December 21, the days will continue to get shorter. The light will be limited and far from adequate to produce Vitamin D, even in those who manage to expose their skin to the sunniest parts of the day.

According to a Statistics Canada report called Vitamin D Blood Levels of Canadians, 40 per cent of the population experiences Vitamin D deficiency in the winter.

In the long, dark winters of the Yukon, that number can be expected to be higher.

Vitamin D plays a number of important roles in our health. It is essential for the development and maintenance of healthy teeth and bones. Vitamin D deficiencies have been connected to a variety of chronic conditions including osteoporosis, cancer, cardiovascular disease, and multiple sclerosis.

Recent studies have now also added Alzheimer’s disease and dementia to the growing list of conditions that may result from a deficiency of this important vitamin.

What is Vitamin D?

Vitamin D isn’t actually a single vitamin, but rather several related fat-soluble cholesterol-like vitamin variants. Fully active Vitamin D is manufactured with the participation of a number of organs and processes throughout the whole body. The skin, bloodstream, liver, and kidneys all contribute.

The whole process begins when sunlight interacts with a form of cholesterol in the skin to create cholecalciferol. This is then converted in the body to active forms of Vitamin D.

When Vitamin D is ingested, it is absorbed through the intestinal walls and is transported to the liver for storage and use throughout the body.

The Dementia Connection

An international group of researchers followed 1,658 healthy participants aged 65 and older for almost six years as part of a study for the American Academy of Neurology. .. At the end of the research period, lead researcher Dr. David Llewellyn and his team found that 171 of the participants had developed dementia, most in the form of Alzheimer’s disease.

Participants with mild Vitamin D deficiency had a 53 per cent increased risk of developing dementia and a 69 per cent greater risk of developing Alzheimer’s disease. More concerning was that those with a severe deficiency were more than twice as likely to develop the cognitive conditions as those who had adequate levels of Vitamin D.

Getting Vitamin D

Living in the North, there is no real way in the winter – save a trip to Mexico – to get Vitamin D from sun exposure alone. Rising no more than 30 degrees over the horizon, we will never have the type of light that allows for natural Vitamin D production.

While there aren’t many food sources that are high in Vitamin D, there are a few that can be added to your diet: egg yolks, cod liver oil, butter, and oily fish, such as sardines, mackerel, salmon, and herring.

There are a number of supplements available for Vitamin D. While a supplement may be needed to counter deficiency in the long dark months of winter, exercise some caution and common sense. As a fat-soluble vitamin, toxicity is possible from overdosing and can result in diarrhea, excessive thirst, nausea, weakness, and headaches. Long-term ingestion of excessive doses can also cause problems with the calcification and hardening of tissues.

Having your Vitamin D levels tested annually can help determine your needs and the efficacy of your chosen approach to counter deficiency.

With populations in Canada aging, the prevalence of Alzheimer’s disease and dementia are expected to rise. Understanding that there may be a link with Vitamin D deficiency offers a risk factor that doctors and aging populations can manage. While more research is needed, the studies to date offer a solid starting point.