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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

What are vitamin D levels in sunny southern California?

What are vitamin D levels in sunny southern California? Los Angeles, at 34 degrees latitude, is surely a haven for vitamin D sufficiency. Or is it?

Dr Elaine Kaptein and colleagues of the University of Southern California Medical Center recently studied 3,276 inner city patients from LA.

Kaptein EM, Yi SS, Endres DB, Kaptein JS, Chan LS. Vitamin D Deficiency in Urban Indigent Patients in Southern California. Endocr Pract. 2013 Jan 21:1-28.

Using Quest Diagnostic commercial lab [which uses Liquid Chromatography – Tandem Mass Spectrometry (LCMS/ MS)] they found that 6.5% of people had severe vitamin D deficiency [25(OH) D <10 ng/mL]. They found it in 5% of Hispanics, 7% of Asians, 9% of Whites, and 15% of African Americans.

Prevalence of 25(OH) D <20 ng/mL was 35% overall, 34% in Hispanics, 32% in Asians, 33% in Whites, and 49% in African Americans. While the authors failed to state what percentage of people were above 30 ng/ml, a figure in the paper looked to only show about 35% above the threshold. Only about 5% of the population appeared to have natural levels, which are greater than 40 ng/ml.

Vitamin D status in indigenous populations: Part 1. Posted on August 27, 2012 by John Cannell, MD

New study: Vitamin D levels of the Maasai and Hadzabe of Africa. Posted on January 25, 2012 by John Cannell, MD

The southern California researchers found significant risk factors for deficiency, many of which are well-known risk factors. This included:

  • being in the hospital
  • being African American
  • having your blood tested in winter months(although  not much seasonal variation was found)

The significant relative risks for diseases in severe vitamin D deficiency [25(OH) D <10 ng/mL] were 1.5 for diabetes mellitus, 2.2 for chronic kidney disease, 2.1 for any cardiac disease, and 1.7 for liver diseases.

The authors stated that,

“Obviously, fortified foods and 25(OH) D supplements were inadequate in most of our patients.”

They added,

“Since 25(OH) D deficiency has the potential to contribute to morbidity, this problem should be suspected, diagnosed, and adequately treated to improve the health status in this at risk population.”


  About: John Cannell, MD

Dr. John Cannell is founder of the Vitamin D Council. He has written many peer-reviewed papers on vitamin D and speaks frequently across the United States on the subject. Dr. Cannell holds an M.D. and has served the medical field as a general practitioner, emergency physician, and psychiatrist.
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6 Responses to What are vitamin D levels in sunny southern California?

  1. Rita and Misty says:

    Thanks, Dr. Cannell, for an excellent post…it serves as a reminder regarding the fallacy many individuals have regarding southern locations and vitamin d sufficiency.

    This just is not true!

    We in the Vitamin D community know that because of our indoor lifestyles, Vitamin D deficiency is at epidemic proportions in the United States…actually worldwide.

    And, of course, it is worse among those with darker skin pigmentation, as melanin factors greatly into Vitamin D production.

    The sunlight needs for people with darker skin pigmentation, living at higher latitudes, are immense and are not being met. A lighter pigmented person standing in full sun can produce a day’s bodily requirement of Vitamin D in about 15 minutes. In stark contrast, a person with darker skin pigmentation, standing in the same spot, will need approximately 6 times more sun exposure to produce the same amount of vitamin D.

    According to reports by the United States Center for Disease Control and Prevention, African American suffer greatly from chronic diseases such as cancer, heart disease, fibromyalgia, lupus, and obesity which can be effectively controlled or prevented with adequate vitamin D supplementation.

    Unfortunately, many African Americans do not know about the health enhancing properties of vitamin D so their health continues to deteriorate.

    Despite the alarming health situation for Blacks, conventional medical practitioners do not seem to be informing Black people that they may need to take at least 5,000 IU of vitamin D3, in supplement form, every day; and that Black children should also be given adequate amounts of vitamin D3 on a daily basis, because food and drinks do not supply adequate amounts of vitamin D. Instead, all of us continue to be overloaded with prescription medications that treat the symptoms of illnesses while the causative factors are left unaddressed.

    This is an issue of great concern to me, and I would be willing to further discuss it with members of our Vitamin D community. Feel free to reach out to me at : umileritac@aol.com.

    To Sunny Days,


  2. Rebecca Oshiro says:

    4 years ago while living in Escondido, CA my husband, father, mother and I all had our vitamin D level tested. Our results were 17, 16, 27, and 22 respectively. So much for living in sunny So Cal!

  3. Brant Cebulla says:

    We’re in San Luis Obispo, CA, which some lump into Southern California. At 35 degrees North, there are very few minutes in which our shadows are shorter than us during the winter days. So even beach goers have a hard time adequately getting their vitamin D from the sun in the winter.

    And like most Americans, even during the summer, we’re in the office at high-noon, not out in the sun. Sounds hypocritical, but it’s the nature of the 21st century. No matter where you live, you have to be in tune with your vitamin D nutrition.

  4. Rita and Misty says:

    Certainly agreed, Brant…no matter where you live, it’s difficult to rely solely on sun exposure to adequately meet your Vitamin D requirements….

    It’s a fallacy…plain and simple….

    Now, let’s stop and think about how much more difficult it is for those with darker skin pigmentation….

    Relying solely on the sun for Vitamin D is simply a mistake…for everyone…and especially for those with darker skin levels….

  5. clubtan says:

    Sun beds offer a great alternative for those who find themselves indoors when the Sun is high in the sky. The benefits of sun exposure reach farther than just vitamin D, especially in winter.

  6. ekaptein@usc.edu says:

    Light skinned people in sunny climates wear hats and clothing as well as susnscreen with CPF 15 or higher. The concern for skin cancer and premature aging of the skin with UV exposure is high. Also the indoor life style of the majority of the working people as well as those with chronic illnesses is a major factor. So, Southern California, like most sunny climates, most likely has a large proportion of their population with vitamin D deficiency which should be diagnosed and corrected.