Vitamin Deficiencies: Are You Getting Enough Vitamins? Part 3: Vitamin D

Sources of Vitamin D

The sun's rays create vitamin D in our body. Although direct sunlight exposure is a good source of vitamin D, many people do not get enough sun due to season change, latitude, or lifestyle. In Canada we get less vitamin D due to our northern latitude, eh. Fair-skinned people might get enough in 5-10 minutes on a sunny day, a few times a week. But cloudy days, the low light of winter, and the use of sunblock all interfere. Older people and those with darker skin tones don’t make as much vitamin D from sun exposure. Experts agree it is better to rely on food and supplements.

There are very few natural foods that contain vitamin D. The best food sources are the flesh of fatty fish (salmon, tuna, mackerel) or fish liver oils. Small amounts of vitamin D are also found in beef liver, cheese, and egg yolks. In Canada, milk is fortified by law with 35–40 IU per 100 mL, as is margarine at ≥530 IU per 100 g.

How much Vitamin D do we need?

The best first step to assess your vitamin D needs is to test 25-hydroxyvitamin D levels. Ideal blood levels should fall between 50-80 ng/mL. For adults up to 5,000 IU daily may be recommended to maintain optimal vitamin D levels.

What does Vitamin D do in our bodies?

• Bone health

• Immune health

• Modulation of cell growth

• Brain health & function

• Neuromuscular function

• Reduction of inflammation

Who is most at risk for vitamin D deficiency?

• Breastfed infants

• Adults 50 years & older

• Limited sun exposure

• People with dark skin

• Overweight, obese or gastric bypass surgery

• Dairy allergy or lactose intolerance

• Inflammatory bowel disease or other conditions causing poor fat absorption.

Deficiency signs & symptoms

Vitamin D deficiency in children causes rickets: thin, brittle and misshapen bones. In adults, deficiency causes the same softening and weakening of the bones, known as osteomalacia. If untreated, osteomalacia leads to osteoporosis.

Bone pain, muscle weakness and intermittent muscular spasms can be symptoms of vitamin D deficiency. However, for many people, the symptoms are subtle. Even without symptoms, too little vitamin D can pose health risks. Low blood levels of the vitamin have been associated with the following:

• Increased risk of death from cardiovascular disease

• Cognitive Impairment in older adults

• Severe asthma in children

• Cancer

There are also links between low vitamin D and MS, diabetes type 2, obesity, depression, and painful menstruation. Vitamin D deficiency is linked with Seasonal Affective Disorder (SAD); large doses of vitamin D may help with mild depression.

Vitamin D testing is available at most Naturopathic Clinics including mine, Island Natural Health.

Do you have a comment, question or a topic for Dr. Callas? If so please contact him