Vitamin D is an essential nutrient the body needs for many vital processes. It promotes healthy bones and teeth, regulates insulin levels, benefits the immune system, and supports lung function, cardiovascular health, and brain and nervous system health.⁵ Vitamin D also plays a vital role in protecting against conditions such as heart disease, high blood pressure, diabetes, some types of cancer, multiple sclerosis, and infections and immune system disorders.¹

Vitamin D is also critical for eye health. From improving tear function to reducing the risk of macular degeneration, cataracts, and glaucoma, vitamin D has a positive effect on eyesight in many ways.³

Vitamin D deficiency

Vitamin D deficiency is when there is insufficient vitamin D in the body. This is often due to lack of sunlight exposure, inadequate dietary sources and malabsorption. A lack of vitamin D has been associated with cancer, immune disorders, heart disease, high blood pressure, osteoporosis, bone pain, depression, asthma, multiple sclerosis, and even dementia.

Being deficient in Vitamin D can also have a negative impact on eye health. Vitamin D deficiency has been associated with conditions such as age-related macular degeneration, diabetic retinopathy, uveitis, dry eye syndrome and impaired tear function.³

Vitamin D deficiency is a global problem affecting an estimated 1 billion individuals. Nearly 42% of all adults in the U.S. are vitamin D deficient and some experts believe those numbers could be even higher.¹

There are many influencing factors that may lead to lower vitamin D levels. Below are some of the risk factors for vitamin D deficiency.

Risk factors for vitamin D deficiency:

• Individuals over the age of 65 years
• Insufficient sunlight exposure
• Being overweight or obese
• Diet lacking fish or dairy
• Medication use that alters vitamin D metabolism
• Sedentary lifestyle

Signs and symptoms of vitamin D deficiency may include:¹

• Regular sickness or infection
• Fatigue
• Bone pain
• Muscle weakness, muscle aches or cramps
• Low mood
• Hair loss

Best sources of vitamin D

Getting adequate sunlight is the best way to help the body produce enough vitamin D. Experts suggest getting 10-30 minutes per day, several times a week to maintain healthy blood levels. This time may fluctuate depending on how sensitive your skin is to sunlight.⁹

Certain foods can also be good sources of vitamin D such as:

• Fish: fatty fish, such as salmon, sardines, mackerel, and tuna
• Nuts and seeds: almonds, Brazil nuts, pumpkin seeds and sesame seeds
• Fruits and vegetables: avocado, mushrooms, dark leafy vegetables such as spinach and collard greens
• Egg yolks
• Beef liver
• Dairy: cheese, fortified milk, yogurt
• Fortified cereals and juices

Diagnosing vitamin D deficiency

It may be difficult to determine if you have a vitamin D deficiency. However, if you think you may be deficient, it is important to discuss any concerns or symptoms with your primary care physician who will order the appropriate testing.

References:

1. https://my.clevelandclinic.org/health/articles/15050-vitamin-d–vitamin-d-deficiency
2. https://pubmed.ncbi.nlm.nih.gov/21310306/
3. https://www.aafp.org/afp/2009/1015/p841.html
4. https://www.hopkinsmedicine.org/health/wellness-and-prevention/vitamin-d-and-the-heart
5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3068797/
6. https://www.medicalnewstoday.com/articles/161618#risks
7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3068797/
8. https://www.medicalnewstoday.com/articles/326167#vitamin-d-and-the-sun