Quebec's fall and winter are well known for their short days and lack of sunlight. Although snow and cold can create picturesque landscapes, they also have a significant impact on our health, particularly on our vitamin D levels. This vitamin, often called "the sunshine vitamin," plays a crucial role in our overall well-being. In this article, we will explore why it is essential to maintain adequate vitamin D levels and why supplementation is particularly important for Quebecers.
What is vitamin D and why do you need it?
Vitamin D is a fat-soluble vitamin that is essential for several bodily functions, including:
- Bone health: Vitamin D helps absorb calcium and phosphorus, two essential minerals for strong bones and teeth. A lack of vitamin D can lead to conditions such as osteoporosis and bone fractures.
- Immune system function: It plays a crucial role in maintaining a robust immune system, helping protect against various infections (colds, flu...), diabetes, cardiovascular disease, and certain cancers.
- Mental health: Adequate vitamin D levels are also linked to better mood and a reduced risk of depression, especially during the winter months.
Why is supplementation important?
In summer, our bodies can produce vitamin D when our skin is exposed to sunlight. However, in Quebec, the fall and winter months are long, and sunlight is scarce. In addition, extreme cold forces us to cover most of our skin, thereby reducing our body's ability to synthesize vitamin D naturally.
How to supplement with vitamin D
Vitamin D supplementation is simple and accessible. Experts generally recommend between 1,000 IU and 2,000 IU of vitamin D per day for adults, but this may vary depending on your age, weight, and specific needs. It is always recommended to consult a healthcare professional before starting supplementation to determine the dose that is best for you, so speak with your pharmacist or doctor if you are wondering how much to take.
Personally, I take 2,000 IU as a supplement every day.
Which foods provide vitamin D?
| Food | Vitamin D (IU/100 g) |
|---|---|
| Cod liver oil | 10,000 IU |
| Cooked wild salmon | 600 - 1000 UI |
| Cooked farmed salmon | 250 - 300 UI |
| Canned tuna | 236 IU |
| Cooked mackerel | 250 - 345 UI |
| Canned sardines | 300 - 400 UI |
| Herring (fresh, marinated, or smoked) | 160 - 680 UI |
| Egg yolk | 20 - 50 UI |
| Vitamin D-fortified milk | 40 - 120 UI |
| Maitake mushrooms (exposed to sunlight) | 562 IU |
| Dried shiitake mushrooms | 100 IU |
| Cooked beef liver | 50 IU |
| Cheddar cheese | 40 IU |
| Butter | 60 IU |
This table gives an idea of the main dietary sources of vitamin D and their approximate content per 100 g serving.
Conclusion
For Quebecers, maintaining adequate vitamin D levels is a challenge, especially during the fall and winter months. Taking vitamin D supplements is an effective way to protect your bone health, strengthen your immune system, and maintain good mental health throughout the year.
I strongly encourage you to take care of your health by ensuring adequate vitamin D levels, especially during Quebec's long cold season.
Danielle, your Zenit nutritionist
References:
Barbarawi, M., Kheiri, B., Zayed, Y., Barbarawi, O., Dhillon, H., Swaid, B., … & Manson, J. E. (2019). Vitamin D supplementation and cardiovascular disease risks in more than 83 000 individuals in 21 randomized clinical trials: a meta-analysis. JAMA cardiology, 4(8), 765-776.
Bolland, M. J., Grey, A., & Avenell, A. (2018). Effects of vitamin D supplementation on musculoskeletal health: a systematic review, meta-analysis, and trial sequential analysis. The lancet Diabetes & endocrinology, 6(11), 847-858.
Canada, H. (2012). Vitamin D and calcium: updated dietary reference intakes.
Chung, M., Lee, J., Terasawa, T., Lau, J., & Trikalinos, T. A. (2011). Vitamin D with or without calcium supplementation for prevention of cancer and fractures: an updated meta-analysis for the US Preventive Services Task Force. Annals of internal medicine, 155(12), 827-838.
Dibaba, D. T. (2019). Effect of vitamin D supplementation on serum lipid profiles: a systematic review and meta-analysis. Nutrition reviews, 77(12), 890-902.
Godel, J. C., Canadian Paediatric Society, & First Nations, Inuit and Métis Health Committee. (2007). Vitamin D supplementation: recommendations for Canadian mothers and infants. Paediatrics & child health, 12(7), 583-589.
Halliday, T. M., Peterson, N. J., Thomas, J. J., Kleppinger, K., Hollis, B. W., & Larson-Meyer, D. E. (2011). Vitamin D status relative to diet, lifestyle, injury, and illness in college athletes. Medicine and science in sports and exercise, 43(2), 335-343.
Larson-Meyer, D. E. (2007). Vegetarian sports nutrition: Food choices and eating plans for fitness and performance. Human Kinetics Publishers.
Larson-Meyer, D. E., & Willis, K. S. (2010). Vitamin D and athletes. Current sports medicine reports, 9(4), 220-226.
Rizzoli, R. (2021). Vitamin D supplementation: upper limit for safety revisited?. Aging clinical and experimental research, 33(1), 19-24.
Zhang, Y., Fang, F., Tang, J., Jia, L., Feng, Y., Xu, P., & Faramand, A. (2019). Association between vitamin D supplementation and mortality: systematic review and meta-analysis. Bmj, 366.