Among the alphabet vitamins, vitamin D ranks high in its importance because it is one of the nutrients with one of the highest rates of deficiency (together with vitamins A and B12), which has significant health implications.
Numerous factors contribute to the rising prevalence of vitamin D deficiencies, including:
- Decreased exposure to ultraviolet (UV) rays due to broad-spectrum sunscreens.
- Less time spent outdoors (50-90% of vitamin D is absorbed through the skin via sunlight).
- Poor absorption due to common digestive issues such as celiac disease, inflammatory bowel disease (IBD), chronic pancreatic insufficiency, and cystic fibrosis, among others.
- Lower dietary vitamin D intakes.
Down on vitamin D
We need adequate vitamin D for optimal bone health, as it regulates calcium absorption, and proper immune function.
This important vitamin also regulates the expression of genes across at least 160 pathways that have a wide variety of biologic functions, and plays an important role in human development in the womb5, 6.
When we don’t get enough vitamin D, we can experience numerous health-related issues. For instance, vitamin D deficiency is associated with rickets in children and osteoporosis in adults, as well as cancer, cardiovascular disease, diabetes, autoimmune diseases, and depression.
Broad health benefits
Emerging research continues to affirm vitamin D’s essential role in human health and continually expands the list of conditions and diseases that are linked to deficiency.
For example, a study published in 2023 that gave 60 000 IU per month of vitamin D3 to half of the 21 302 elderly (aged 60-84) participants in the study (the other half received a placebo) determined that: “Vitamin D supplementation might reduce the incidence of major cardiovascular events”.
This finding was echoed in another 2023 study published in the American Heart Journal, which found taking higher-than-recommended doses of vitamin D for five years reduced the risk of atrial fibrillation in older men and women.
And a meta-analysis published in 2021 in the journal Nature Reviews Endocrinology, affirmed the need to correct severe vitamin D deficiencies, as research reviewed in the analysis showed that “supplementation of individuals with vitamin D deficiency modestly delays age-related bone loss and progression to T2DM, and improves lung function” and that “vitamin D supplementation results in a modest decrease in cancer mortality”.
In relation to vitamin D’s link to reduced cancer risk, researchers from the University of Eastern Finland and Kuopio University Hospital observed fewer cases of melanoma among regular users of vitamin D supplements than among non-users. The findings were published in the journal Melanoma Research.
And there are potential brain benefits, too, as findings from a recent large-scale study11 suggest that taking vitamin D supplements may help ward off dementia.
When 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, the team found that taking vitamin D was associated with living dementia-free for longer, and that the group who took supplements experienced 40% fewer dementia diagnoses.
READ MORE | Smart Nutrition: The Food-Mood Connection
Boosting vitamin D levels
Your body primarily creates vitamin D through direct sun exposure by synthesising cholesterol via the action of sunlight on a form of vitamin D contained in the skin called cholecalciferol (also known as vitamin D3), which is then stored in the body as it is a fat-soluble vitamin.
We also get vitamin D from dietary sources including egg yolks, beef liver, and fatty fish such as tuna, herring, mackerel and salmon, as well as fortified dairy and cereal products.
In supplement form, vitamin D is available in capsule or tablet form, most commonly as vitamin D3 (cholecalciferol). These products aim to increase circulating vitamin D levels.
We also have the option to use a sublingual spray to deliver vitamin D directly into the bloodstream to boost levels as it diffuses through tissues under the tongue, an area rich in blood vessels.
As vitamin D requirements are highly individualised, any recommended supplemental approaches should be determined in consultation with a qualified healthcare practitioner.
Tips to boost vitamin D levels:
- Boost skin to the sun’s ultraviolet rays for a few minutes each day. Optimal durations vary depending on skin type.
- Get this ultraviolet exposure as near to solar noon as possible – generally between 10h00 and 14h00.
- Add more vitamin D-rich foods to your daily diet.
- Supplement with vitamin D3 products if additional support is required.
Author: Pedro van Gaalen
When he’s not writing about sport or health and fitness, Pedro is probably out training for his next marathon or ultra-marathon. He’s worked as a fitness professional and as a marketing and comms expert. He now combines his passions in his role as managing editor at Fitness magazine.