Vitamin D is known as the sunshine vitamin because we make it when ultraviolet light from the sun strikes the skin. This compound behaves like a hormone. Numerous physiological functions depend heavily on it.

People with low levels of vitamin D are more likely to become depressed (Wong, Chin & Ima-Nirwana, Current Drug Targets, Sep. 13, 2017). They are also at greater risk of multiple sclerosis (Spencer, Bell & DeLuca, Journal of Neurology, Neurosurgery, and Psychiatry, Aug. 31, 2017).

Older women are weaker when their levels are low (Iolascon et al, European Journal of Physical and Rehabilitation Medicine, online July 10, 2017). People with insufficient levels of vitamin D also suffer cardiovascular and skeletal complications. In addition, those who get enough of this vitamin fight off infections such as tuberculosis better (McCullough & Lehrer, Journal of Steroid Biochemistry and Molecular Biology, online July 26, 2017). How can you ensure that you have adequate vitamin D?

Sunshine and Cod Liver Oil for Improving Vitamin D:

Q. At the end of last winter, in March, I saw my doctor and learned that my vitamin D tested at 17! I was shocked, as I walk outdoors every day, all year long.

I am a black woman and I live in South Carolina. Without asking anything about my lifestyle, my doc prescribed 50,000 IUs of vitamin D2 every week for three months. I told her I’d follow through, but my plan was to instead resume taking my “favorite” (not!) cod liver oil (CLO). This is something I usually do, but had not done for about a year.

Three months later, after taking CLO daily, followed by a milk chaser, my vitamin D level was 48. My doctor was none the wiser. Of course, three months later meant it was now June and I had had more sunshine on my skin during my daily walks.

I was not happy that my doctor didn’t discuss the implications of my low vitamin D level. I was delighted, though, that my old-fashioned remedy–cod liver oil–worked! Thanks for your wisdom, grandma!

Boosting Vitamin D Levels:

A. According to the Endocrine Society, a 25-hydroxyvitamin D level below 20 indicates deficiency. At 17, you had a right to be alarmed.

Cod Liver Oil:

Old-fashioned cod liver oil contains vitamins D and A. Grandmothers dosed their families with it during the winter, assuming it acted like a tonic. Cod liver oil contains vitamin D3. People apparently assimilate and utilize this form of vitamin D more easily than the vitamin D2 in some supplements (Shieh et al, Journal of Clinical Endocrinology and Metabolism, Aug. 2016).


Walking outdoors with your skin exposed to sunshine will boost vitamin D levels. A person like you with darker skin needs more sun exposure to make enough of the vitamin. Our Guide to Vitamin D Deficiency describes the consequences of low vitamin D levels as well as the pros and cons of your doctor’s prescription.

Related People's Pharmacy Health Guide

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