This site uses cookies to store information on your computer. Learn more x


Providing perspectives on recent research into vitamins and nutritionals


Can You Predict Vitamin D Status Without a Lab Test?

By Julia Bird

Much has been written about the global epidemic of vitamin D deficiency. Yet, there is still a considerable lack of awareness of vitamin D deficiency in the general population. Perhaps this has something to do with the current range of tests available. Unlike other vitamins, skin synthesis after sun exposure is an important source of vitamin D, therefore the dietary analysis tools that can normally be used to estimate vitamin and mineral intakes are not useful for vitamin D. The current selection of options to measure vitamin D status include:

-          Accurate but slow and expensive blood tests that can be done under the guidance of a doctor and require a venous blood sample, with results available within a few days from when the sample was taken

-          Self-tests that use a minimally invasive blood spot from a finger prick done at home, results available in a few days

-          Rapid tests in systems such as Nanospeed and Cue, that are yet to be fully commercialized but have results available in 10 minutes.

-          Non-validated online tests in atrocious English that estimate vitamin D levels

-          Pressure-pain thresholds on the breast bone or shin bone, which are only weakly correlated with vitamin D levels (see Dresser and colleagues).

Recently, Xu and co-workers looked at vitamin D levels in sub-tropical Hong Kong, China. They were primarily interested in seasonal fluctuations and their effects on vitamin D levels. They included blood samples from 2694 adult and child subjects, and among the children, a diet and lifestyle questionnaire was included to see if elements could be identified that affected vitamin D levels.

The authors found a 5-week delay between peak and trough sunlight intensity and vitamin D levels, that is, vitamin D levels were lowest around 5 weeks after the lowest solar radiation was measured. The results of the questionnaire in children provide results that could be used for a questionnaire to assess likelihood of vitamin D deficiency. While non-modifiable factors such as female sex and being a teenager were associated with lower levels of vitamin D, other modifiable factors were found. Having had a suntan in the past year, consuming fish, consuming milk and cod liver oil intake improved vitamin D status in the simple model, while egg consumption also improved vitamin D status is the adjusted model.

Interestingly, using sunscreen, recent sun exposure, use of a vitamin D or multivitamin supplement, and skin color were not associated with vitamin D levels. The reason for this may be that some of these behaviors lead to other changes in behavior that may counteract the expected effect. For example, people who wear sunscreen block the exposure of their skin to the sun, however people only wear sunscreen if they are going to be outside. The people who don’t wear sunscreen may be more likely to stay inside, where they will also not produce any vitamin D on their skin. Likewise with skin color, people with darker skin produce less vitamin D when exposed to the sun, however as they are also less likely to burn, they may spend more time in the sun.

We have reported on using questionnaires to predict vitamin D status in the past. Questionnaires offer us a low-cost way to predict who is at risk of vitamin D deficiency. Blood tests are better, but have some drawbacks. Personalized nutrition is coming. For now, we have questionnaires.

Main citation:

Cuiling Xu, Ranawaka A. P. M. Perera, Yap-Hang Chan, Vicky J. Fang, Sophia Ng, Dennis K. M. Ip, Andrea May-Sin Kam, Gabriel M. Leung, J. S. Malik Peiris and Benjamin J. Cowling. British Journal of Nutrition. Published online: 08 June 2015.

Supporting citations:

Dresser J, MacIntyre M, Chisholm B, Lawson GE. Is bone tenderness, as measured by manual algometry, associated with vitamin D deficiency? The Journal of the Canadian Chiropractic Association. 2014;58(3):320-327.

Vitamin D Council. New survey highlights the need for increased awareness and knowledge of vitamin D. October 31, 2014.

You are signed in as:
whn May 11, 2017 10:47 AM
Under the snow peak, Zhuo is the lake. "Why? So why do this? I just want to be a mother, want to have a child of their own, but you are not willing to pay, every time you are affixed to the fine do not shoot, God, I hate you! I hate you! You are a ruthless selfish person. "A stunning woman stands in the water naked upper body, while crying while patting the lake, chest full of breasts with the body twist Rhythm of the shaking, emitting a white holy luster. The shore of a Qiu must go back and forth pacing, watching a woman in the water sprinkle soared, heart disgust: "You crazy woman, really want the child to be crazy, two people more comfortable, have children do? "Said the air Xiu Xiu turned away, and ignored the woman's crying. "Trained and trained !!" see her husband and ignore their own to leave alone, the woman heartbroken, crying for a while slowly came to the shore. "Call" Suddenly the lake rises in a bucket-like thick snake tail, snake body up to two scales scales glittering, the woman every step of the chest breast and snake around the swing is really good look, line to the lake only to find this stunning woman Turned out to be the first snake body, upper body naked near ten feet, the snake is more than two feet long, on the shore to drive clouds to the east away. Wanshan ancestors, the top of the Kunlun, jade virtual peak of a Tsing Yi old man sigh: "Oh! And quarreled, and nearly nearly eight thousand eight hundred and thirty back! I was this sister is really hard, married the fool Every day to know what Jiugong gossip, stood such a beautiful wife do not accompany the woman is the need to coax you! You do not have time to accompany her, according to her request to give birth to a child to the companion, but not willing to pay A trace of God, really a stubborn and selfish guy, three days to quarrel, has been quarreling for more than a million years, so when the day is a head ah? "Think of this thing between husband and wife is not easy to intervene , Helplessly shook his head and turned to the hole and walked. Line to the way suddenly paused the body, smile soon as: it seems trouble or come to the door, and want to hide can not hide ah! "Brother!" Midwive came a woman's call, come is just in the lake crying people first snake body stunning woman, the old man has always been feeling that the arrival of those who stopped to wait for. Old man slowly turned the body, asked to smile asked: "Shimei today how free to see my old man? Is not and Fuxi quarreled?" Women down the cloud Jiao Jiao said: "Brother, I am not a special trip to To see you, nor to listen to you say that thousands of times all the way, I just come to you to help find a child's way. "" What is the way to find my child! "Old man at the foot of a staggering," Shimei You still bypass my old bones it! If it was Fuxi know that it is not Grilled my skin. "The old man frightened, hand pendulum and rattle like. Woman's face crimson, snapped: "Brother, where do you want to go! Old right! I just come to you to find a child's magic, not to say that you and that ... ..." "What Old man gas beard Alice, Long said: "chaos beginning to this point, I have lived for three million years, and now alone or alone in vain, you! You actually said that I am not serious "The old man angry big sleeves flushed back, the woman was covered with" Puchi "smile. The original, the chaos opened to the beginning of this also five people, they are Hongjun, Pangu, Nu Wa, Pan Xing, Fu Xi, because Hongjun is the birth of the first world of wisdom, behind a few people more or less Have been educated by Hongjun, so everyone is consistent with the Hongjun respect for the big brother. Later Pangu and the plate Xing two fight for the brother of a war, then that war to play the darkness, broken mountains and rivers, sun and the moon without light, the final panic body into a towering Kunlun will be calm in the abyss, can be described as a lose-lose The Now this world also Hongjun, Nu Wa, Fu Xi three, this old man is Hongjun, the first snake body of the woman is of course Nu Wa. So this Hongjun think not single is immune, Nu Wa is laughing for this
0 Replies » Reply