Study assesses dietary requirements for vitamin D in the winter
Posted on 8 December 2008
Last week one of my blogs focused on a recent study which explored the relationship between vitamin D levels and risk of cardiovascular disease. This issue is timely for those of us who are in our winters, and who may therefore be running short on sunlight and vitamin D. This issue is perhaps even more timely when one considers that a study just out (published in the December edition of the American Journal of Clinical Nutrition) has found some evidence that vitamin D levels are on a bit of a downward trend in American men [1]. This study is accompanied by an editorial which points out that if this research reflects reality, then we have cause for concern [2]. The editorial points our attention to the fact that vitamin D affects a multitude of systems and processes in the body including bone health, cardiovascular disease and cancer risk, as well functions that relate to immune, pancreatic, muscle and brain function.
One question we might ask is what level of vitamin D is required to ensure optimal health, particularly in the winter when sunlight is highly unlikely to meet our needs in this respect. The issue was addressed by the authors of the study I covered last week, and they quoted research suggesting that 1000-2000 IU is required for many individuals to meet their vitamin D requirements. As it happens, December
Published December 8, 2008 . Filed under: Uncategorized
Wm Davis, MD, who tests a lot of people for D says that the tablets don’t raise your blood level, only the gel caps do. He writes the HeartScan blog and is a cardiologist.
December 8, 2008 @ 6:10 pm
My 10 you son needed to have some blood drawn for another reason a few weeks ago, so I asked that his Vit D levels get checked too. I was eager to see, because since school started in late August, he gets far less time outside in prime Vit D sunlight hours) so he’s been taking Vit D3 of about 3,000iU per day, per the Vitamin D Council’s recommendation of 1,000 iU per 25 pounds of body weight in winter.
My son’s level was 72, so I was happy to see his levels are great and that the Vit D3 supplementing wasn’t too much. We live in So Cal, so he does get perhaps more sun than others do in winter, but even so, school and time at home indoors, plus cooler weather clothing during the shorter prime D times still limit Vit D3 production from sunlight. I’ll back off the supplements in the spring when his sunlight exposure increases.
He also didn’t catch “the cold that turned into a lingering, awful cough” that spread around the school population last month, creating lost of empty desks in the classrooms. Then again, he also consumes little immune-suppressing sugar.
December 8, 2008 @ 10:41 pm
Hi Dr. Briffa. How was the Vitamin D administered? Thanks.
December 8, 2008 @ 10:44 pm
Dave
The D3 was administered in capsule form (produced by Banner Pharmacaps in the Netherlands).
December 8, 2008 @ 10:54 pm
Did they happen to mention if it was powdered or in an oil base?
December 8, 2008 @ 11:06 pm
‘fraid not.
December 8, 2008 @ 11:17 pm
The optimal lab value of 25-hyroxyvitamin D at Kingston-upon-Thames NHS hospital is from 75 to 200 nmol/L. I take 2,000ius of D3 (a gel cap) per day and my levels vary between 155 nmol/L and 200 nmol/L – my endocrinologist checks it regularly.
Anne
December 9, 2008 @ 2:07 am
Hi Dr Briffa
Do you think it is a good idea for people with Hypoparathyroidism to take a high dose D3 as well as alfacalcidol/calcitriol ? There are currently opposing schools of thought on this.
Thanks
December 12, 2008 @ 2:33 pm
Was it here I read that as soon as your shadow is longer than your body, you will be getting no appreciable Vitamin D production via the UVB rays?
December 12, 2008 @ 9:25 pm
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March 12, 2010 @ 12:17 am