The low down… We are now understanding that what was established as the recommended
daily allowance (RDA) for vitamin D was GROSSLY underestimated decades ago due to a
statistical error. If you have been taking the recommended daily dose in your multi-vitamin,
it likely has NOT been enough!
The RDA is 400 IU/day Most multi-vitamins have about 400 IU of vitamin D. (We have always
recommended more.) For years at Crossroads Chiropractic we have used the rule of thumb to
supplement 35 IU’s of Vitamin D per pound of body weight. That leaves most adults in the
3500-7000 IU per day range. (Much closer to the corrected analysis of the data used by the
institute of Medicine that found it took 8895 IU/day for 97.5% of individuals to achieve the
correct values of Vitamin D.)
Vitamin D is important for bone health, but also YOUR IMMUNE SYSTEM! People who are low
on their levels of vitamin D are more sick and take longer to recover from colds and flus. We
saw this with worse COVID outcomes during the pandemic for those with low vitamin D levels.
It is February… we have been away from good sun exposure to make our Vitamin D for
months now, if you’re not supplementing yet, you’re very late to the party!
The role of vitamin D in innate and adaptive immunity is critical. A statistical error in the estimation of
the recommended dietary allowance (RDA) for vitamin D was recently discovered; in a correct analysis
of the data used by the Institute of Medicine, it was found that 8895 IU/d was needed for 97.5% of
individuals to achieve values ≥50 nmol/L. Another study confirmed that 6201 IU/d was needed to
achieve 75 nmol/L and 9122 IU/d was needed to reach 100 nmol/L. The largest meta-analysis ever
conducted of studies published between 1966 and 2013 showed that 25-hydroxyvitamin D levels <75
nmol/L may be too low for safety and associated with higher all-cause mortality, demolishing the
previously presumed U-shape curve of mortality associated with vitamin D levels. Since all-disease
mortality is reduced to 1.0 with serum vitamin D levels ≥100 nmol/L, we call public health authorities to
consider designating as the RDA at least three-fourths of the levels proposed by the Endocrine Society
Expert Committee as safe upper tolerable daily intake doses. This could lead to a recommendation of
1000 IU for children <1 year on enriched formula and 1500 IU for breastfed children older than 6
months, 3000 IU for children >1 year of age, and around 8000 IU for young adults and thereafter.
Actions are urgently needed to protect the global population from vitamin D deficiency.
J Prev Med Public Health. 2017 May 10;50(4):278–281. doi: 10.3961/jpmph.16.111
Pregnant or know someone who is? Read on…
Reduction in Childhood Asthma When Mom
Takes “extra” Vitamin D while Pregnant
Quoted from the research:
“These results demonstrate a statistically significant reduction in asthma among offspring aged 3 and 6 years
when comparing vitamin D supplementation (4400 IU/d) to the standard prenatal multivitamin with vitamin D
(400 IU/d).”
“Furthermore, these post hoc analyses found that vitamin D supplementation led to a decrease in total serum
IgE levels and improved lung function in children compared to those whose mothers received a placebo
alongside the standard prenatal multivitamin with vitamin D.”
“It is now known that vitamin D has a myriad of nonbone effects that are important for overall health. Vitamin
D has been found to exert profound effects on immune function, capable of modulating both the innate and
adaptive immune responses. Moreover, vitamin D plays a critical role in the maintenance and completion of a
healthy human pregnancy. During pregnancy, vitamin D helps in modulating the maternal immune system to
reduce inflammation and prevent rejection of the fetus and enhance placental functioning and fetal
organogenesis.”
“We would recommend that all pregnant women consider a daily intake of at least 4400 IU vitamin D3
throughout their pregnancy, starting at the time of conception. It is worth noting that our detailed monitoring
of potential adverse events found no attributable adverse events to vitamin D at this dose, during both 3-year
and 6-year follow up intervals, for both mother and child.”
Weiss et al. (2023) Prenatal Vitamin D Supplementation to Prevent Childhood Asthma: 15-year Results from the Vitamin D Antenatal
Asthma Reduction Trial (VDAART). Journal of Allergy and Clinical Immunology Vol 153, No 2