A tan does not equal vitamin D

14. May 2008 William Davis (8)
The sun is getting stronger and the days are getting longer, even here in Wisconsin.

Some people are coming to the office with nice tans obtained by sunning themselves for several hours. Others have come back from winter getaways to Florida, Arizona, or the tropics, also sporting nice, dark tans.

Several people, in fact, were so confident that sunning themselves provided sufficient vitamin D that they reduced their usual dose. Some even stopped their vitamin D altogether.

But, when blood levels of 25(OH) vitamin D were checked, they were virtually all low, sometimes as low as <20 ng/ml. Yet all had nice tans.

Why does this happen? Why would people with dark tans remain deficient in vitamin D?

One big factor is age: Anyone over 40 years old is fooling themselves if they think that a tan ensures raising vitamin D levels to a desirable range. Also, the more you tan, the more melanin skin pigment accumulates, and the more vitamin D activation in the skin is blocked.

Weight is another factor: Heavier people need more vitamin D, sometimes three- or four-fold more than slender people.

Why does aging result in inefficient skin activation of vitamin D? It seems that, once we are beyond our reproductively useful years, this ticking clock of aging gets triggered. The older we get, the less activation of vitamin D occurs in our skin, the less of the youth-maintaining, disease-preventing benefits of vitamin D we obtain with sun exposure.

The message: Don't rely on a tan to gauge the adequacy of vitamin D. Maybe that works when you're 16 years old, but not at age 50 or 60. There's only one way to know your vitamin D status: a blood level of 25(OH) vitamin D.


Copyright 2008 William Davis, MD
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Comments (8) -

  • Anonymous

    5/14/2008 10:03:00 AM |

    It's all about UVB exposure and amount of pigment and cholesterol in the skin.

  • ethyl d

    5/14/2008 4:36:00 PM |

    Just to clarify, I assume therefore, that, even if sunshine exposure does not guarantee adequate vitamin D levels as one ages, dietary vitamin D through D-rich foods or gel capsules do?

  • Ross

    5/14/2008 5:23:00 PM |

    Still another factor is that tanning lotions and sunscreens selectively block UVB rays, which are the higher-energy rays our bodies need to synthesize Vitamin D.  The lower-energy UVA rays that cause tanning but don't help with Vitamin D are permitted through in much higher quantities by all sunscreen chemistries.

    Like many things in this world, when we humans interfere with the natural, we tend to screw it up.  Just like we're better off with whole milk, whole eggs, whole meats (leave the skin on the chicken, it's the best part!), etc.  We also benefit most from the whole spectrum of sunlight.  Not so much that we burn, but definitely not filtered of the best and most useful components.

    If you want a tan to count towards your Vitamin D, repeatedly get outside for short periods of time without sunscreen.  I'd still recommend a supplement, since your body has all sorts of ways to manage too much, and very few ways to manage not enough.

  • Anonymous

    5/14/2008 11:32:00 PM |

    Dr. Davis, thank you for reminding us of the importance of vitamin D supplementation.   When addressing vit. D supplementation, please, we need to keep on stressing that it needs to be D3 in GEL CAPS.   There are lots of people who are hearing the vit D supplementation message, run to the drugstore and buy D tablets (often 1000 IU D2).  Their doctors and pharmacists are saying they are doing the right thing.  But from what I understand it is rather useless.  Oil based D3 in the right, larger, quantity, is what matters, because that is what the digestive system can absorb.

    Could you provide a medical research reference that clearly shows why D3 in gel caps is the only way to go?  I would like to print lots of copies to give to my friends, parents, etc....

  • Anonymous

    5/16/2008 1:11:00 PM |

    A test comparing D2 to D3:

    http://www.nutraingredients.com/news/ng.asp?id=82331

  • Anna

    5/16/2008 6:50:00 PM |

    Check out the Vitamin D Council for a wealth of research on Vit D supplementation:  http://www.vitamindcouncil.org/

    I was so impressed with this non-profit's work that I added them to my list of charitable causes.

  • Anne

    6/9/2008 7:56:00 PM |

    Dear Dr Davis,

    I just got back from my holidays in France and am catching up with your blogs. This one interested me. I just received the results of my vitamin D test taken before I went away, the 25(OH)vitamin D3 test, and my levels are 384 nmol/L (153 ng/ml) which I understand is much, much too high.

    I am mystified at this result as I live in the UK where there isn't usually much sun and I don't sunbathe anyway and I've been taking 4,000iu D3 only since January. Obviously I am stopping the supplements right away but am very concerned.

    Anne

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15. January 2011 William Davis (13)
Jeanne enjoyed her Christmas holidays. She especially liked sharing the cookies she made for her grandchildren, sneaking 2 or 3 every day over a couple of weeks. On top of this, she enjoyed the Christmas candy, egg nog, leftover stuffing and cranberry sauce, topped off with a night of nutritional debauchery on New Year's Eve.

Lipid panel in October:

Total cholesterol 146 mg/dl
LDL cholesterol 72 mg/dl
HDL cholesterol 64 mg/dl
Triglycerides 49 mg/dl

Lipid panel in early January:

Total cholesterol 229 mg/dl
LDL cholesterol 141 mg/dl
HDL cholesterol 59 mg/dl
Triglycerides 147 mg/dl


I call the holidays The Annual Wheat and Sugar Frenzy. It's the carbohydrates, especially those from products made of wheat and sucrose, that caused the marked shifts in Jeanne's lipid patterns. Let's take each parameter apart:

--Triglycerides go up due to de novo lipogenesis, liver conversion of carbohydrates into triglycerides. Triglycerides enter the bloodstream as VLDL particles which, in turn, interact with LDL and HDL.

--LDL goes up because carbohydrate exposure increases VLDL, followed by conversion to LDL. The triglyceride-rich LDL created is converted to small LDL particles. Had we measured small LDL changes in Jeanne, we likely would have measured something like an increase (by NMR) from 800 nmol/L to 1600 nmol/L, a carbohydrate effect.

--The increased VLDL also makes HDL triglyceride-rich, cause more rapid degradation of HDL particles. (It also makes them smaller, like LDL.) Given sufficient time (a few more months), HDL would drop into the 40's.

--Total cholesterol changes reflect the composite of the above numbers. (Total cholesterol = LDL cholesterol + HDL cholesterol + Trig/5) (Note that, as HDL drops, so will total cholesterol; that's why this value is worthless and should be ignored.)

So don't be surprised by the above distortions after a period of carbohydrate indulgence. Although your unwitting primary care doc will see such changes as opportunity for Lipitor, it is nothing more than the cascade of effects from a carbohydrate-driven distortion of lipoproteins.
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Comments (13) -

  • Michaelf

    1/15/2011 2:59:27 PM |

    Why so many lipid panels?

    Doesn't cholesterol naturally ebb and flow?  Or does it only ebb and flow when we feed it?

    For my taste the second panel is better, other than the HDL.  I'd say she did a good job getting her Cholesterol up over the holidays....

    One of the highlighted lines in my Taubes book is the piece about the lower the cholesterol the higher the incidence of cancer.  Correlation I know but wasnt all the science about cholesterol a well choreographed dance around correlation.

    My father was a cancer patient and a heart patient.  He "naturally" had cholesterol in the 150-160 range and was sick his whole life.  

    IMHO that womans cholesterol is doing what it does to save her life.  Rising to wrangle up the garbage she's dumping down her throat.  

    My fathers never rose to combat the garbage he was dumping down his throat.  What are your thoughts on that?

    If this stuff happens as you say, a fairly simple pattern, then why the differences?

  • Brent

    1/15/2011 3:22:09 PM |

    Dr. Davis - This is off topic for this particular post, but I want to suggest the next blog post for you.  

    First, cudos for keeping this blog informational only, without a hint of commercialism in in.  However, I and perhaps others who read it have seriously considered contacting your office for an appointment to become patients, even though we live in other parts of the country.

    Would you consider posting a topic on the blog of how this could work?  My thoughts are to have necessary tests done in advance of a visit, so that things which normally take 2-3 visits could be accomplished in one. Is a list of these things something that could be determined by a phone interview with your office staff when the appointment is being made?  Can your office arrange for heart scans to be done in Milwaukee in the AM for a PM appointment with you?

    Important question: Is a heart scan at a closer facility (Still 3 hours away) & track your plaque membership (not yet done because I've not had a scan yet) just as good as a visit to your office once a year or would I get additional benefits becoming a patient? i.e., can you rely on scan scoring done by others if I wanted your opinion on the results?

  • Lori Miller

    1/15/2011 4:38:56 PM |

    Two other things all those carbs will do to susceptible people is give them bloating and acid reflux. The posts on that subject have been my two most popular over the past month.

    Re: cholesterol, mine is 140. The total didn't change much when I cut way back on the carbs, but the ratio of HDL:LDL improved. If I'm sick or riddled with cancer, I'm afraid it's escaped my notice. My liver must be making all I need.

  • Anna

    1/15/2011 5:16:45 PM |

    I don't miss the cookies, overly sweet eggnog, and Christmas candy at all, since I revised my diet in early 2004.  I don't gain holiday weight anymore; in fact, some years I lose a couple pounds between Thanksgiving and New Years.

    When I celebrate during the holidays with food, I do indulge (if you can call it, that because my indulgences tend to be nutrient-dense and very satisfying, too) with rich paté, lovely artisan cheeses, fish roe (caviar) and deviled eggs, fresh veggie slices, and bacon-wrapped scallops and shrimp, etc.  I make egg nog that isn't nearly so sweet as well as super easy homemade truffles with very dark chocolate, which has just a small amount of sugar.

  • revelo

    1/15/2011 5:21:24 PM |

    I eat a high carb diet (60% typically, lots of oats, beans, potatoes) and just got back my first test result:

    Cholesterol, Total   152
    Triglycerides         39
    HDL Cholesterol       70
    VLDL Cholesterol calc  8
    LDL Cholesterol calc  74

    I'm lean (16% body fat according to my electronic scale, 12% according to a formula I found on the internet) and get plenty of moderate exercise (yoga and walking). So it appears all those carbs are NOT turning to Triglycerides in me.

    Rather, when I eat carbs, the glucose goes into the muscles. After I finish my last meal for for the day, the body gradually burns off this stored glucose so that the muscles are mostly depleted by the next morning, when I break my nightly fast. Isn't this how the body is supposed to work? I have to disagree with this notion that the muscles can only store a couple of hundred grams of glucose. I think that amount of glucose that can be stored increases in lean people who exercise and routinely eat large amounts of carbs.

  • Michaelfgu

    1/15/2011 5:33:52 PM |

    Brent, You have been reading my mind! Yes, Dr Davis please tell us how best this could best be accomplished as per Brent's comment!

  • Might-o'chondri-AL

    1/15/2011 7:05:52 PM |

    Bit over simplified; unless holiday indulgences (prior to patient's Jan. lab test) were made rich tasting without using any fat &/or cholesterol content
    (and wasn't over eating, nor lazing around).

    Clinic patients are presumably often already suffering with metabolic syndrome. An absolute admonishment is going to become rote patient visit after patient visit.

    Is a prevention strategy for everyone, or just the sedentary and geneticly pre-disposed? One's adult health may be doing well with a contrary diet. By middle age Doc's restrictions might be a pre-emptive strategy for countering metabolic changes to come.

  • shutchings

    1/15/2011 8:26:23 PM |

    So if Jeanne returns to restricting sugar and flour from her diet in January, her profile improves.  Did she leave lasting damage?  Is the risk only that disease will develop during her holiday relapse?

  • Dr. William Davis

    1/15/2011 10:26:20 PM |

    Anna--

    I love the gourmet-bent you've taken with your diet. That's a great direction to go.


    Brent and Michael--

    You can call my office at 414-456-1123 to arrange an out-of-town visit. Alternatively, call the same number to arrange a video teleconference to review lipoproteins or your coronary prevention program. (Video teleconference is not covered by insurance, however.)

  • Anonymous

    1/15/2011 10:54:00 PM |

    I treat so much cholesterol in my patients with bio-identical hormone therapy in addition to nutritional biochemistry / blood test to help rebuild the adrenals and help the body convert the excess cholesterol into the LDL and then into the next hormone called pregnenolone. Most people who have high cholesterol have silent adrenal dysfunctions/ burn out / PTSD whereby the cholesterol does'nt convert into the next hormone.
    Most MD's won't look to check the adrenal and sex hormones in conjunction with and cholesterol test.
    What an oversight eh !

  • Marc

    1/16/2011 7:57:03 PM |

    I used to have very lows trigs (35-45 range), I start eating high fat low carb & 6 month later my trig went up to 79.

    Carbs = elevated trigs??
    Not for me.

      My lowest trigs were in my vegetarian days eating whole wheat, oats, beans etc...when I started upping the fats & meat my trigs went up (even when cutting down wheat, which I dont eat it anymore)

    Could you provide an answer to this mr Davis?

  • Sophie

    1/24/2011 10:49:24 AM |

    I agree that holidays is a season to increase weight gain. Uncontrollable eating can risk our health. There is no any guarantee how long can our body take the cholesterol we're feeding. So proper self-discipline is needed. Low carbohydrate diet is the best diet for those who want to lose weight especially for diabetic people.

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