Reasons to Test Vitamin D Levels

The Powerful Health Benefits of Vitamin D

Vitamin D plays a vital role in overall health, with wide-ranging effects throughout the body. Emerging research continues to expand our understanding of this essential nutrient and why it is important to know when we have a deficiency.

• Immunity and Flu Prevention. Vitamin D helps reduce the risk of infections and inflammation, particularly during the fall and winter flu season. It has been shown to lower the risk of influenza and related complications. In fact, the Canadian government has recommended increased vitamin D intake as part of its strategy to prevent seasonal flu and H1N1 swine flu.
• Mood and Mental Health. Low levels of vitamin D are linked to an increased risk of depression, including seasonal affective disorder (SAD), a type of winter depression influenced by lack of sunlight. Sun exposure, which stimulates vitamin D production in the skin, is known to help lift mood.
• Muscle and Pain Relief. Vitamin D supports healthy calcium levels in the blood, which in turn helps muscles relax and function properly. Low levels of vitamin D can contribute to chronic muscle pain and cramping, including menstrual cramps.
• Cancer Prevention. Research has found that low vitamin D levels are associated with a higher risk of several cancers. Vitamin D supports normal cell growth and communication, helping prevent the uncontrolled cell division that leads to tumors.
• Heart Health. Vitamin D plays a role in protecting the lining of blood vessels, which may reduce the risk of cardiovascular disease, heart attack, stroke, and atherosclerosis.
• Type-1 Diabetes Risk. Adequate vitamin D levels may reduce the risk of developing type-1 diabetes by up to 80%. Studies show that individuals with diabetes often have low levels of vitamin D.
• Autoimmune Disease. Vitamin D helps regulate immune function and may lower the risk of autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, lupus, inflammatory bowel disease, and Hashimoto’s thyroiditis. Supplementation has been shown to reduce the risk of multiple sclerosis by as much as 40%.
• Bone Health and Osteoporosis. Vitamin D is crucial for calcium absorption and bone formation. Without enough vitamin D, bones can become weak and brittle, increasing the risk of fractures and osteoporosis in both men and women as they age.

Why Most People Are Deficient

While the body can produce vitamin D through sun exposure, modern life makes it hard to get enough. Factors like limited outdoor time, clothing coverage, sunscreen use, and darker skin pigmentation reduce vitamin D production. Aging skin also produces significantly less vitamin D, synthesizing up to 75% less than younger skin.

Vitamin D To-Do List

• Check vitamin D levels: Ask the doctor for a blood test to measure 25-OH vitamin D (vitamin D3). Optimal levels for health are generally in the range of 55–80 nmol/L—higher than older “normal” reference ranges.

• Get safe sun exposure: Aim for 20–30 minutes of sunlight on bare skin (without sunscreen) in the morning or late afternoon. Use sunscreen during peak midday hours; sunscreen is important.

• Eat vitamin D–rich foods: Cold-water fish like wild salmon, sardines, cod, and cod liver oil contain vitamin D, though it’s hard to get enough through food alone.

• Supplement wisely: Choose vitamin D3 (cholecalciferol), the biologically active form, over vitamin D2. Work with a knowledgeable healthcare provider to determine the right dose for your individual needs, and monitor calcium, phosphorus, and parathyroid hormone levels as needed.

Vitamin D is essential for lifelong health. Whether through sun, food, or supplements, make sure vitamin D levels are adequate all year long—and always do so under the guidance of a healthcare professional.