Young-Onset Dementia and Vitamin D
Now that the weather is getting warmer my thoughts turn to that most important of nutrients: Vitamin D. From the beginning of April onwards we can make our own vitamin D whenever the weather cooperates and the sun shines! While vitamin D plays a role in the prevention of many chronic diseases, in this issue I focus on the prevention of just one – dementia. Not just in the elderly, but in the growing number of younger adults developing this frightening affliction.
In this issue
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Young-onset dementia and vitamin D
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Vitamin deficiencies during pregnancy
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Recipe: Mid-week main course salad
How young is too young for dementia?
Currently, over half a million Canadians are living with dementia, a number that is projected to double in the next 15 years. Particularly distressing is the fact that while dementia predominantly affects older adults, the condition is not exclusive to the very old.
Young-onset dementia, also known as early-onset dementia, refers to dementia diagnosed between the ages of 30 and 65. While it is less common than dementia in older adults, it still represents a significant and growing portion of cases, with approximately 5% of all dementia cases occurring in individuals under 65 years old.1 To date, a 19-year-old Chinese youth is the youngest person to be identified with dementia.2
Vitamin D and the brain
Why is young-onset dementia increasing? We really don’t fully understand that yet, and multiple factors may be at play. Now a new study suggests low blood levels of vitamin D may be one of those factors.
The UK biobank is a large-scale biomedical research resource containing genetic, life-style and health information and biological samples (blood, urine, etc.) from half a million people in the UK. The new study, published in the journal JAMA Neurology, analyzed data from everyone in the database who initially has no signs of dementia and followed them for an average of 8 years, and found a clear link between low blood levels of vitamin D and increased risk of developing young-onset dementia.3
We often worry that if a parent or near relative had been diagnosed with dementia that we might be genetically predisposed to the same disease, and in this study genetic factors did increase the risk. But in line with many other published studies, genetics accounted for only a tiny proportion of cases. According to Health Canada only 1% of all dementia cases in Canadians can be attributed to genetics.4
Apart from low blood levels of vitamin D, the presence of other health conditions, such as heart disease, diabetes or depression increased the risk of developing young-onset dementia. Many of these factors may be beyond our control. However, making sure we get sufficient vitamin D is something we all should do.
And since vitamin D deficiency is also implicated in the development of conditions like breast and colorectal cancers – two cancers that also appear to be increasing in younger individuals – it makes sense to make sure we maintain healthy blood levels of the sunshine vitamin from an early age.
The all-round benefits of vitamin D
At least 1,000 different genes governing virtually every tissue in the body are now thought to be regulated by 1,25-dihydroxyvitamin D3 (1,25[OH]D), the active form of the vitamin, including those involved in absorption of calcium, immune system functioning and cancer prevention.5
Vitamin D is often referred to as the “sunshine vitamin” because it is synthesized in the skin on exposure to ultraviolet light (UVB), so historically we obtained most of our vitamin D from sun exposure. But the further north we live, the more difficult it is for our skin to manufacture vitamin D. For part of the year the angle of the sun is too oblique and contains too little energy to generate vitamin D. Sunscreen is designed to block UVB and prevent sunburn, so when properly applied it will also lower vitamin D synthesis.
In the winter months at latitudes above 37 degrees north or below 37 degrees south of the equator, the skin can’t make vitamin D from the sun, and if you live in these areas, you are at greater risk of vitamin D deficiency. In Toronto where I currently live, we can only make vitamin D form the beginning of April to the end of September, so unless we take vitamin D supplements, we develop progressively lower blood levels over the winter. Even in summer, work often keeps us indoors. If we cover up for religious or cultural reasons, we also court vitamin D deficiency.
Skin pigmentation is a major risk factor for deficiency as skin pigmentation acts as a natural sunscreen. Compared with light-skinned individuals, very dark-skinned individuals require approximately six times the sun exposure to produce the same amount of vitamin D.6
Practice sun safety
Harnessing the benefits of sunlight while avoiding its potential risks requires careful planning. For most light-skinned individuals, a half-hour in the summer sun in a bathing suit can initiate the release of 50,000 IU (1.25 mg) vitamin D into the circulation within 24 hours of exposure, and about and 8,000–10,000 IU in dark-skinned individuals.7
So, should we increase our sun exposure? Exposing skin to the sun for about 10 to 20 minutes during the summer months is considered safe for most people. But know your skin type: Individuals with fair skin may require less time in the sun compared to those with darker skin. After that, practice sun safety. Wear protective clothing, such as hats, long sleeves and sunglasses, and use sunscreen on exposed skin if staying in the sun for prolonged periods. And never, never, never burn!
Supplementing with vitamin D – how much is enough?
In regions with limited sunlight or during the winter months, it is wise to take vitamin D supplements. But how much is enough? Curiously, the recommended daily intake (RDI) has been officially set in North America at 600 IU regardless of skin type – a trivial amount compared to the amount our ancestors who hunted and gathered, or toiled in the fields would have been acclimatized to making.
What matters most is not so much the amount of vitamin D you take, but the blood level you achieve. This is because the blood level of vitamin D is the best indicator of how much vitamin D is available for use by the body’s tissues and organs. The reference range for blood levels of vitamin D runs from 75 – 250 nmol/L (30 – 100 ng/ml in the USA). After a week’s winter sunshine holiday, vitamin D levels of are likely to be near the top of the current reference range.
Blood levels can vary wildly between individual taking exactly the same amount of vitamin D.8 Below is an illustration of just this phenomenon. You can see with doses of vitamin D from 1000-10,000, blood levels achieved can range from almost zero (extreme deficiency) to the mid-to high end of the reference range.
Garland CF et al. Anticancer Res. 2011 Feb;31(2):607-11
So, there is no one size fits all regarding vitamin D supplementation: The amount of supplements needed varies from one person to another, depending on various factors such as genetics, age, health status, and gut health. Hence the desirability of blood tests.
Optimizing vitamin D intakes
According to Health Canada, anyone over the age of nine can safely take 4000 IU of vitamin D daily, without a blood test or supervision. This may, or may not, ensure your blood levels will be in the therapeutic range. Optimal blood levels are necessary for a multitude of physiological functions, including bone health, immune function, cancer prevention and overall health. For example, studies have shown an 80% decreased risk of breast cancer with blood levels of 150 nmol/L (60 ng/ml) or higher. 9
Therefore, it’s essential to monitor blood levels of vitamin D from time to time. A knowledgeable healthcare professional will help you adjust your supplement doses accordingly to ensure optimal health outcomes. Don’t test blood levels during the summer months, or within 8 weeks of a winter sunshine holiday.
For more information on brain health and vitamin D see my book The Healthy Brain published by HarperCollins Canada
Nutritional deficiencies common in pregnancy
A mother’s vitamin status before she gets pregnant and during the entire pregnancy is extremely important for healthy outcomes – not just for the baby, but also for the mother. Adequate intakes of essential nutrients such as folic acid, iron, calcium, magnesium, omega 3 fats and vitamin D are crucial during this critical period and shortfalls of any of these vital nutrients can lead to serious consequences, such as compromised bone health and impaired immune function.
Multivitamins specially formulated for prenatal use and during pregnancy are widely available and can provide a convenient way to address nutritional gaps. However, a recent research study suggests that some lower dose prenatal multivitamins on the market may be inadequate for preconception and pregnancy. Researchers looked at nutritional intakes in 1,729 women aged 18 to 38 years who were pregnant or planning to become pregnant. Blood levels of multiple essential nutrients were checked, starting in preconception and continuing throughout pregnancy and later during breastfeeding. 10
Although all the women lived in high-income countries (the UK, The Netherlands and Singapore), where access to healthy food and/or nutrient supplements was not an issue, the researchers found that at the start of the study an astonishing 90% of all participants had low or marginal blood levels for one or more vitamin or minerals.
Half the women were given a standard vitamin supplement, and the other half an enhanced vitamin supplement containing additional B-vitamins, vitamin D and zinc. Blood levels of vitamins and minerals were then measured at regular intervals during the pregnancy and for 6 months after delivery.
After one month blood levels of nutrients were substantially higher among participants in the group given the enhanced supplement than those in the control group, and this continued throughout pregnancy. Vitamin D deficiency (blood levels less and 50 nmol/L) during late pregnancy was seen in 35 percent of those given the standard multivitamin and mineral supplement, and in 8.5 percent of those given the enhanced supplement.
For some time now we have known that inadequate nutrition, especially in the last trimester, adversely affects the baby’s brain development, potentially leading to long-term cognitive and developmental issues. And so, supplementing with multivitamins is the standard recommendation during pregnancy and breast feeding.
This study suggests that women planning to get pregnant should seek out a product that contains higher levels of B-vitamins and add additional vitamin D. Other studies have shown that 4000 IU of vitamin D is safe during pregnancy and significantly reduces the risk of complications of pregnancy including primary Cesarean section. 11
If possible, consult with a knowledgeable health care practitioner about the use of other supplements during pregnancy.
More information on optimal diet and supplements during pregnancy can be found in my book The Healthy Brain (HarperCollins Canada 2017)
Steak (or Chicken) Salad with Balsamic Vinaigrette:
Use leftover protein for a tasty and filling midweek dinner that’s quick and easy to prepare. Serves 4. Provides 3-4 servings of vegetable and 30g of protein per serving.
Ingredients:
- 12 oz. leftover steak, turkey or chicken, sliced
- 8 oz. mixed salad greens (lettuce, spinach, arugula) – about 8 cups
- 1 cup lightly cooked sweet corn kernels (frozen)
- 1 large avocado, sliced
- 1 cup of sliced, bottled roasted red pepper
- 8 oz. cherry tomatoes, halved
- 1 medium red or sweet white onion, finely sliced
For the Balsamic Vinaigrette:
- 1/4 cup white balsamic vinegar
- 1/3 cup extra virgin olive oil
- 1 clove garlic, minced
- 1 tablespoon Dijon mustard
- Salt and pepper to taste
Instructions:
- In a large bowl, combine the mixed salad greens, sweet corn, avocado slices, roasted red peppers, cherry tomatoes, and finely sliced red onion
- In a small bowl, whisk together balsamic vinegar, olive oil, minced garlic, Dijon mustard, salt, and pepper. Adjust the seasoning to your taste.
- Drizzle the balsamic vinaigrette over the salad. Toss gently to coat all the ingredients evenly.
- Arrange the leftover steak or chicken slices on top of the salad.
Feel free to make this dressing your own by adding other favorite ingredients or herbs, and adjusting the dressing ratios to suit your palate. I like to use white balsamic vinegar, as it is lighter than regular balsamic vinegar and has a natural sweetness. But apple cider or white wine vinegar will work just as well.
Bon appétit!
References
[1]. Young-onset dementia diagnosis, management and care: a narrative review Loi SM, Cations M, Velakoulis D. Med J Aust. 2023 Mar 6;218(4):182-189
[2]. https://www.psychiatrist.com/news/a-19-year-old-is-youngest-ever-to-be-diagnosed-with-alzheimers/
[3]. Risk Factors for Young-Onset Dementia in the UK Biobank. Hendriks S et al. JAMA Neurol. 2024 Feb 1;81(2):134-142
[5]. Benefits of sunlight: a bright spot for human health. Mead MN. Environ Health Perspect. 2008 Apr;116(4):A160-7.
[6]. Vitamin D and skin physiology: a D-lightful story. Holick MF, Chen TC, Lu Z, et al. J Bone Miner Res 2007;22 Suppl 2:V28–33.
[7]. Benefits of sunlight: a bright spot for human health. Mead MN. Environ Health Perspect. 2008 Apr;116(4):A160-7
[8]. Vitamin D supplement doses and serum 25-hydroxyvitamin D in the range associated with cancer prevention. Garland CF, French CB, Baggerly LL, Heaney RP. Anticancer Res. 2011 Feb;31(2):607-11
[9]. Breast Cancer Risk Markedly Lower with Serum 25-Hydroxyvitamin D Concentrations ≥60 vs <20 Ng/Ml (150 vs 50 Nmol/L): Pooled Analysis of Two Randomized Trials and a Prospective Cohort. McDonnell, S.L. et al. PLoS ONE 2018, 13, e0199265.
[10]. Maternal B-vitamin and vitamin D status before, during, and after pregnancy and the influence of supplementation preconception and during pregnancy: Prespecified secondary analysis of the NiPPeR double-blind randomized controlled trial. Godfrey KM et al.PLoS Med. 2023 Dec 5;20(12):e1004260.
[11]. Vitamin D supplementation during pregnancy: double-blind, randomized clinical trial of safety and effectiveness. Hollis BW et al. J Bone Miner Res. 2011 Oct;26(10):2341-57